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US3287119A - Process for the sensitization of photoconductors - Google Patents

Process for the sensitization of photoconductors Download PDF

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US3287119A
US3287119A US426358A US42635865A US3287119A US 3287119 A US3287119 A US 3287119A US 426358 A US426358 A US 426358A US 42635865 A US42635865 A US 42635865A US 3287119 A US3287119 A US 3287119A
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parts
weight
acid
photoconductor
electron
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Hoegl Helmut
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Azoplate Corp
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Azoplate Corp
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/02—Charge-receiving layers
    • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
    • G03G5/06—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being organic
    • G03G5/0622—Heterocyclic compounds
    • G03G5/0624—Heterocyclic compounds containing one hetero ring
    • G03G5/0627—Heterocyclic compounds containing one hetero ring being five-membered
    • G03G5/0629—Heterocyclic compounds containing one hetero ring being five-membered containing one hetero atom
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
    • Y10S430/001—Electric or magnetic imagery, e.g., xerography, electrography, magnetography, etc. Process, composition, or product
    • Y10S430/10—Donor-acceptor complex photoconductor

Definitions

  • Electrophotographic material normally consists of a support on which there is a photoconductive substance, this coating being provided in the absence of light with an electrostatic charge. Then, the material is exposed to light behind a master, or an episcopic image is projected thereon, so that an electrostatic image is formed which corresponds to the master. This image is developed by being briefly contacted with a resin powder, whereupon a visible image is formed which is fixed by heating or by the action of solvents. In this way, an image of the master which is resistant to abrasion is obtained electrophotographically.
  • the absorption maxima of the organic photoconductors are mostly in the ultra-violet region of the spectrum.
  • The-addition of these dyestuft' sensitizers achieves the result that the photoconductors become sensitive to visible light.
  • the dyestuflf sensitizers cause a displacement of the available sensitivity from the ultraviolet region to the visible region.
  • the sensitivity to visible light at first increases rapidly, but further additions give an increase in sensitivity which is much less than would be expected, and still further additions finally give no appreciable increase in sensitivity.
  • the dyestulf sensitizers have the disadvantage that they color the coating considerably.
  • the maximum achievable increase in sensitivity can seldom be utilized because then the photoconductor coatings have an intensity of color that is undesirable.
  • Colorless or practically colorless photoconductor coatings are desired, since colored material can be employed only in special cases. If additions of dyestuff sensitizers are such as not to adversely afiect the coloring of the coating for practical purposes, the sensitizing effect often does not meet the demands of general usage. Further, the dyestutf sensitizers have the disadvantage that they bleach out relatively quickly so that their sensitizing action tends to be lost during the storage of the electrophotographic material.
  • a process for the sensitization of photoconductor coatings has now been found in which organic substances, containing polarizing residues and being capable of serving as electron-acceptors in a molecule complex, having low molecular weight, i.e. being non-resinous, being colorless or of pale color and having a melting point above room temperature, are added to the photoconductor coatings.
  • Substances which are primarily of interest as photoconductor coatings in accordance with the present process are those which can serve as electron donors in molecule complexes of the donor/acceptor type (known as Er-complex) and contain at least one aromatic or heterocyclic ring, which may be substituted.
  • Such photoconductors include aromatic hydrocarbons such as naphthalene, anthracene, benzanthrene, chrysene, p-diphenylbenzene, diphenyl anthracene, p-terphenyl, p-quaterphenyl, sexiphenyl; heterocycles such as N-alkyl carbazole, thiodiphenylamine, oxadiazoles, e.g., 2,5-bis-(p-amiuophenyl)-l,3,4-oxadiazole and its N-alkyl and N-acyl derivatives; triazoles such as 2,5 bis-(p-aminophenyl)- l,3 ,4-triazole and its N-alkyl and N-acyl derivatives; imidazolones and imidazolthiones, e.g., 1,3,4,5-tetraphenyl-imidazolone-Z and 1,3,4,5-te
  • 1,3,5-triphenyl-pyrazoline 1,3,5-triphenyl-pyrazoline; hydrated imidazoles, e.g., 1,3-diphenyl-tetrahydroimidazole; oxazole derivates such as 2,5-diphenyloxazole-2- p-dimethylamino-4,S-diphenyloxazole; thiazole derivatives such as 2-p-dia1kylaminophenyLmethyl-benzthiazole; as also thefollowing:
  • Molecule complexes are defined in H. A. Staabs Einbowung in die theoretician organische' Chemie (Introduction to Theoretical Organic Chemistry), Verlag Chemie, 1959, pp. 694-707, and by L. I. Andrews, Chemical Review, vol. 54, 1954, pp. 713-777.
  • the donor/ acceptor complex (r-complexes) and charge-transfer complexes which are formed from an electron-acceptor and an electron-donor are included.
  • the photoconductors are the electrondonors and the substances here called activatorsto dis tinguish them from the dyestutf sensitizers-are the electron-acceptors.
  • the electron-donors have a low ionization energy and have a tendency to give up electrons. They are bases in the sense of the definition of acids and bases given by G. N. Lewis (H. A. Staab, as above, p. 600).
  • the electron-donors primarily concerned in the present case are the photoconductors described above. These photoconductors consist of aromatic or heterocyclic systems containing a plurality of fused rings, or, alter natively, single rings having substituents which facilitate further electrophilic substitution of the aromatic ring, socalled electron-repellent substituents, as described by L. F. and M. F ieser, Lehrbuch der organischen Ohemie” (Textbook of Organic Chemist y) Verlag Chemie, 1954, p.
  • saturated groups e.g., alkyl groups such as methyl, ethyl, and propyl; alkoxy groups such as methoxy, ethoxy and propoxy; carbalkoxy groups such as carbmethoxy, carbethoxy and carbpropoxy; hydroxyl groups, amino groups and dialkylamino groups such as dimethylamino, diethylamino and dipropylamino.
  • the activators in accordance with the invention are compounds with a high electron-aflinity and have a tendency to take up electrons. They are acids in the sense of Lewis definition. Such properties are possessed by substances having strongly polarizing residues or groupings such as cyano and nitro groups, halogens such as fluorine, chlorine, bromine and iodine; ketone groups, ester groups, acid anhydride groups, acid groups such as, carboxyl groups or the quinone grouping. Strongly polarizing electron-attracting groups of this type are described by L. F. and M. Fieser in the Lehrbuch der organischen Chemie, Verlag Chemie, 1954, p, 651, Table I.
  • these substances with amelting point above room temperature (25 C.) are preferable, i.e. solid substances, because these impart a particularly long shelf life to the photoconductive coatings as a result of their low vapor pressure.
  • Substances which are rather deeply colored such as quinones can be used, but those that are colorless or only weak in color are preferable.
  • Their absorption maximum should preferably be in the ultra-violet region of the spectrum, i.e. below 4,500 A.
  • the activator substances in accordance with the present process should be of lower molecular weight, i.e. between about 50 and 5000, preferably between about 100 and 1000, because with activators of lower molecular weight it is possible for reproducible results to be obtained insofar as sensitivity is concerned.
  • the sensitivity remains constant over rather long periods, since substances of lower molecular weight, unlike those of high molecular weight, undergo hardly any change during storage.
  • 2-bromo-5-nitro-benzoic acid o-Chloronltrobenzene. 2-brom0benz0ic acid Chloracetophenone. Z-chloro-toluene-t-sulphonic acid.-- 2-chlorocinnamic acid. Chloromaleic anhydride 9-chloroacridine 2-chloro-4-nitro-1-benzoic acid. B-chloroacridine 2-chloro-5-nitro-1-benzoic acid. 6-c%0rt;gltrobenzene-5-sulpho- 3chloro-6-nitro-1-benzcic acid.
  • Thymcquinone -2,5,7,IO-tetrachloropyrenequlnone Thymcquinone -2,5,7,IO-tetrachloropyrenequlnone.
  • photoconductive coating containing at least one photoconductor and at least one solid, non-resinous, substani tially colorless, electron-acceptor should contain the photoconductor and electron-acceptor in proportions ranging from substantially less than, equal amounts to a substantial excess of the photoconductor with respect to the: 1 electron-acceptor.
  • the optimum of the proportions 1 varies somewhat according to the substance used. Generally, minor amounts are used, i.e. from about 0.1 to. about 300 moles, preferably from about 1 to about150 conductor and at least one solid, non-resinous, substan-.
  • ceptor in proportions ranging from substantially less than equal amounts to a substantial excess of the electronacceptor with respect to the photoconductor.
  • Theseproportions in which minor amounts of the photocon-v ductor are added to the activator vary according to the substance used; however, in general, amounts from about 0.1 to about 300 moles, preferably from about 1 to about 50 moles photoconductor per 1000 moles activator are used. In some cases, it is also possible to use more 1 than 300 moles photoconductor or activator per .1000 moles activator or photoconductor, respectively, butby exceeding the above range the dark decay of the mixture usually increases, and in such cases coatings made 1 therefrom are inferior.
  • tors such as naphthalene, whose initial sensitivity is very slight, to be given adequate sensitivity for the production of satisfactory images by electrophotographic processes.
  • photoconductive mixtures are obtained which have photoconductivity much higher, than could be expected from the amount of the photoconducfor added to the activator.
  • photoconductivity may be obtained by the addition of dyestuff sensitizers in the same amounts as in the photoconductor-activator mixtures in which the photoconductor, is present in a major amount.
  • the coatings are treated in other respects in accordance with the known processes of electrophotography, i.e. the photoconductor substances are used in the form of thin, coherent homogeneous coatings on a supporting material.
  • the materials used as supports are primarily metals, such as aluminum, zinc, and copper; cellulose products, such as paper and cellulose hydrate; plastics, such as polyvinyl alcohol, polyamides, and polyurethanes.
  • plastics such as cellulose acetate and cellulose butyrate, especially in a partially saponified form, polyesters, polycarbonates, and polyolefins, if they are covered with an electroconductive layer or if they are converted into materials which have the above-mentioned specific conductivity, e.
  • materials are suitable the specific resistance of which is less than ohm-cm, preferably less than 10 ohm-cm.
  • paper is used as the supporting material, it is preferably pretreated against the penetration of coating solutions, e.g., it can be treated with a solution of methyl cellulose or polyvinyl alcohol in water or with a solution of an interpolymer of acrylic acid methyl ester and acrylonitrile in a mixture of acetone and methylethyl ketone, or with solutions of polyamides in aqueous alcohols or with dispersions of such substances.
  • coating solutions e.g., it can be treated with a solution of methyl cellulose or polyvinyl alcohol in water or with a solution of an interpolymer of acrylic acid methyl ester and acrylonitrile in a mixture of acetone and methylethyl ketone, or with solutions of polyamides in aqueous alcohols or with dispersions of such substances.
  • the photoconductive compounds are preferably dissolved in organic solvents such as benzene, acetone, methylene chloride or ethyleneglycol monomethylether or other organic solvents or in mixtures of such solvents, and resins and the activators-and possibly also the dyestufi sensitizers-are advantageously added thereto.
  • organic solvents such as benzene, acetone, methylene chloride or ethyleneglycol monomethylether or other organic solvents or in mixtures of such solvents, and resins and the activators-and possibly also the dyestufi sensitizers-are advantageously added thereto.
  • organic solvents such as benzene, acetone, methylene chloride or ethyleneglycol monomethylether or other organic solvents or in mixtures of such solvents
  • resins and the activators-and possibly also the dyestufi sensitizers-are advantageously added thereto are coated upon the supporting material in the normal manner, e.g., by immersion processes, painting or roller application
  • a number of the compounds in question can be applied together to the supporting material or the compounds can be applied in association with other photoconductive sub stances.
  • Resins primarily of interest as additions to the photoconductor coatings include natural resins such as balsam resins, colophony and shellac, synthetic resins such as coumarone resins and indene resins, processed natural substances such as cellulose ethers; polymers such as vinyl polymers, e.g. polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl acetals, polyvinyl alcohol, polyvinyl ethers, polyacrylic and polymethacrylic acid esters, isobutylene and chlorinated rubber.
  • natural resins such as balsam resins, colophony and shellac
  • synthetic resins such as coumarone resins and indene resins
  • processed natural substances such as cellulose ethers
  • polymers such as vinyl polymers, e.g. polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl acetals, polyvin
  • the proportion of resin to photoconductor substance can vary very greatly. Mixtures of from two parts of resin and one part of photoconductor substance to two parts of photoconductor substance and one part of resin are .to be preferred. Mixtures of the two substances in equal parts by weight are particularly favorable.
  • dyestufi sensitizers can be used in addition to the activators. Even very small additions of sensitizer, e.g., less than 0.01 percent, give good results. In general, however, 0.01 to 5 percent, and preferably 0.1 to 3 percent of dyestufi sensitizer is added to the photoconductor coatings. The addition of larger quantities is possible but in general is not accompanied by any considerable increase in sensitivity.
  • dyestufi sensitizers which may be used with good results, and some with very good results. They are taken from Schultz Farbstofitabellen (7th edition, 1931, 1st vol.):
  • Triarylmet-hane dyestuffs such as Brilliant Green (No. 760, p. 314), Victoria Blue B (No. 822, p. 347 Methyl Violet (No. 783, p. 327), Crystal Violet (No. 785, p. 329), Acid Violet 6B (No. 831, p. 351); xanthcne dyestufis, namely rhodamines, such as Rhod-amine B (No. 864, p. 365), Rhodamine 66 (No. 866, p. 366),Rhodamine G Extra (No. 865, p. 366), Sulphorhodamine B (No. 863, p.
  • Eosin G No. 870, p. 368
  • FEDG Fast Acid Eosin G
  • phthaleins such as Eosin S (No. 883, p. 375), Eosin A (No. 881, p. 374), Erythrosin (No. 886, p. 376), Phloxin (No. 890, p. 378), Bengal Rose (No. 889, p.. 378), and Fluorescein (No. 880, p. 373); thiazine dyestufis such as Methylene Blue (No. 1038, p. 449); acridine dyestuffs such as Acridine Yellow (No. 901, p. 383), Acridine Orange (No.
  • quinoline dyestuffs such as Pinacyanol (No. 924, p. 396) and Cryptocyanine '(No. 927,. p; 397 cyanine dyestuffs, e.g., Cyanine (No. 921, p. 394) and chlorophyll.
  • the photoconductive coating is charged by means of, for example, a corona discharge with a charging apparatus maintained at 6000-7000 volts-
  • the electro-copying material is then exposed to light in contact with a master.
  • an episcopic or diascopic image is projected thereon.
  • An electrostatic image correspending to the master is thus produced on thematerial.
  • This invisible image is developed by contact with adeveloper consisting of carrier and toner.
  • the carriers used may be, for example, tiny glass balls, iron powder or tiny plastic balls.
  • the toner consists of a resin-carbon black mixture or a pigmented resin.
  • the toner is used in a grain size of 1 to
  • the developer may also consist of a resin or pigment suspended in a non-conductive liquid in which resins may be dissolved.
  • the image that is made visible by development is then fixed, e.g., by heating with an infra-red radiator to 100-170 0., preferably -150 C. or by treatment with solvents such as trichloroethylene, carbon tetrachloride or ethyl alcohol, or steam. Images corresponding to the master characterized by good contrast effect are obtained.
  • the electrophotographic images can also be used as masters for the plrl'oduction of further copies on any type of light-sensitive s eets.
  • reflex images can be produced also.
  • the application of the activators in accordance with the present process is not restricted to electrophotographic coatings, but can extend to other devices containing photoconductors, e.g., photoelectric cells, photoresistances, sensing heads or camera tubes and electroluminescent apparatus.
  • EXAMPLE 1 A solution containing 26 parts by weight of polyvinyl acetate (e.g., Mowilith 50), 25.6 parts by weight of naphthalene, 0.0415 part by weight of 2,3,7-trinitrofluorenone and 800 parts by volume of toluene is apnliedby means of a coating device to an aluminum foil. After the coating has dried, direct images are produced thereon by the electrophotographic process in the following manner: the coated foil is given a negative electric charge by corona discharge, exposed behind a master to the light of a high-pressure mercury vapor lamp watts, at a distance of 30 cm.) for about 10 seconds and then dusted over with a developer.
  • polyvinyl acetate e.g., Mowilith 50
  • naphthalene e.g., naphthalene
  • 2,3,7-trinitrofluorenone e.g., 2,3,7-trinitrofluorenone
  • the developer consists of tiny glass balls and a mixture of resin and carbon black which has been melted together.
  • a developer of this sort consists of, e.g., 100 parts by weight of tiny glass balls (grain size: 100-400,11. approx.) and a toner (grain size: 20-50 approx.).
  • the toner is prepared by melting together'30 parts by weight of Polystyrol LG, 30 parts by weight of modified maleic acid resin (Beckacite K 105) and 3 parts by weight of Peerless Black Russ 552.
  • the melt 8 7 EXAMPLE 5 A solution of 26 parts by weight of polyvinyl acetate,:
  • EXAMPLE 4 A solution'containing 18 parts by weight of polyvinyl acetate, 18.2 parts by weight of 2,4-bis-(4'-diethylamino phenyl)-1,3,4-triazole and 0.130 part by weight of tetrachlorophthalic anhydride to 500 parts by volume of toluene is applied to an aluminum foil and further procedure is as described in Example 1. The exposure time with a l-watt incandescent lamp is 2 seconds.
  • EXAMPLE 7 A solution containing 26 parts by weight of polyvinyl A solution of 26 parts by weight of polyvinyl acetate, acetate, 24.4 parts by weight of o-dianisidine and 0.0256 17.8 parts by weight of anthracene and 0.3357 part by part by weight of dibromomaleicanhydride in 800 parts weight of hexabromonaphthalic anhydride in 800 parts by volume of toluene is applied to an aluminum foil and by volume of toluene is applied to aluminum and further the material is further processed as described in Examprocedure is, as described in Example 1. With a 125-watt ple 1. The exposure time (125-watt high-pressure merhigh-pressure mercury vapor lamp, the exposure time is cury vapor lamp) is 2 seconds. Without the dibromo- 4 seconds. maleic anhydride addition, it is 10 seconds.
  • the polyvinyl acetate used was the product commercially available under the registered trademark Mowilith C.
  • the maleic acid resin used was the product commercially available under the designation Alrosat.
  • Table B shows further examples of various photoconductors which were activated,.and the reduction in exposure time caused by the activators:
  • naphthalene- 26 21.6 1,5-diethoxynaphthalene.
  • the increase in sensibility obtained by the addition of activating substances may be taken from. a comparison of the degrees of blackening obtained with the activated photoconductive layer and with the unactivated photoconductive layer, under the same customary step wedge (e.g. Kodak No. 2 density strip with color patches).
  • EXAMPLE 8 A solution containing 20 parts by weight of afterchlorinated'polyvinyl chloride with a content of chlorine from 61.7 to 62.3 percent and K-value from 59 to 62, 18.01 parts by weight of 2,4,5,7-tetranitrofluorenone and 0.216 part by weight of 1,5-diethoxynaphthalene dissolved in a mixture of 450 parts by volume toluene and parts by volume butanone is applied to an aluminum foil. The subsequent procedure is that described in Example 1. The exposure time, with a 100 watt incandescent lamp at a distance of 30 centimeters is 2 seconds.
  • the exposure time is about 40 seconds.
  • EXAMPLE 9 A solution of 12 parts by Weight of chlorinated rubber (Pergut 8-40), 5.04 parts by weight of 1,3-dinitrobenzone and 0.106 part by weight of anthracene in 150 parts by volume of toluene is applied to a paper foil and the material is further processed as described in Example 1.
  • the exposure time 125 watt high pressure mercury vapor lamp
  • the exposure time is 20 seconds. Without the anthracene addition, even after an exposure time of 80 seconds, only traces of animage were obtained. This means that the exposed parts of the coating were not discharged and therefore still attracted developer.
  • the exposure time is about 10 sec-.
  • EXAMPLE 12 To a solution containing 28.6 parts by weight of tetral chlorophthalic acid anhydride and 20 parts by weight of afterchlorinated polyvinyl chloride in a mixture of 150 parts by volume of butanone and 450 parts by volume 1 of toluene, X parts by weight of photoconductor and Y parts by weight of dyestuft sensitizer are added. In the following table, the amounts; of, the hotoconductor and sensitizer are given together with the corresponding exposure times. It is advantageous to dissolve the dyestuff sensitizer in a .small amount of ethyleneglycol monomethyl ether before adding it to the solution. The latter is applied to a paper base material and further processed as described in Example 1. The light source used throughout was a 125-watt high pressure mercury vapor lamp and the distance between this lamp and the mate-.
  • rial exposed was about 30 centimeters.
  • Rhodamine B extra..-" 1-2 0.025 Basischreinblau 3 G 2 0.015 Brillantgreen extra 3 0.015 Kristallviolet 2 0.015 Methylenb1ue 0. 5 y vinylcarbazole 0.30 Rhodamine B extr 9 Do None 20 EXAMPLE 10 A solution containing 20 parts by weight of the afterchlorinated polyvinyl chloride mentioned in Example 8, 21.02 parts by weight of benzile and 0370 part by weight of benzidine in a mixture of 450 parts by volume of toluene and 150 parts by volume of butanone is applied to an aluminum foil and the material is further processed as described in Example 1. The exposure time (125 watt high pressure mercury vapor lamp at a distance of 30 centimeters) is 10 seconds. Without the addition of the benzidine activator, even after an exposure time of 4 minutes, no electrophotographic image could be obtained.
  • the exposure time 125 watt high pressure mercury vapor lamp at a distance of 30 centimeters
  • Exposure time Photoconductors (parts by weight): (seconds) 2,2'-dinaphthylamine (0.540) 20 2,5-bis-(4'-diethylamino-phenyl) 1,3,4 oxdiazole (0.730) 5 Poly-N-vinylcarbazole (0.390) 30 EXAMPLE 11 A solution containing 6.2 parts by weight of afterchlorinated polyvinyl chloride, 3.94 parts by weight of 1,5-dichloronaphthalene and 0.145 part by weight of 2,5-bis- (4'-diethylaminophenyl)-1,3,4-oxdiazole in a mixture of 135 parts by volume of toluene and 45 parts by volume of butanone is applied to a paper base and is further processed as described in Example 1.
  • the exposure time (125 watt high pressure mercury vapor lamp at a distance of 30 centimeters) is 10 seconds. Without the addition of the oxdiazole compound, even after an exposure time of 40 seconds, no image could be obtained.
  • the oxdiazole compound is replaced by 0.120 part by weight of EXAMPLE 13 A solution is prepared, containing 57.2 parts by weight:
  • Example 1 In the following table, the added photoconductors are indicated, and the corresponding exposure- As the light source, a -watt high times are given. pressure mercury vapor lamp in a distance of about 30 centimeters from the exposed material was used in all instances.
  • EXAMPLE 15 29.62 parts by weight of phthalic acid anhydride and 33 parts by weight of afterchlorinated polyvinyl chloride are dissolved in 670 parts by volume of toluene and 330 parts by volume of butanone. To 50 parts by volume of the resulting stock solution, one of the photoconductors listed in the following table is added; these coating solutions are applied to an aluminum foil, and further processed as described in Example 1. The light source and the distance of the light source were the same as in Example 13.
  • Exposure time Photoconductor (parts by weight): (seconds) None 1 60 N-ethylcarbazole (0.10) 5 Anthracene (0.09) Chrysene (0.114) Pyrene (0.10) 10 2,2'-dinaphthylamine (0.134) 10 2,3,5-triphenylpyr1'ole (0.153) 10 N0 image obtained.
  • EXAMPLE 16 p 49.2 parts by weight of chloranil and 56 parts by weight of afterchlorinated polyvinyl chloride are dissolved in a mixture of 1170 parts by volume of toluene and parts by volume of butanone. The resulting solution is filled up to 2000 parts by volume with chlorobenzene. To 100 parts by volume of this stock solution, one of the photoconductors listed in the following table is added; the coating solution is applied to an aluminum foil and further processed as described in Example 1. The light source and the distance of the light source were the same as in Example 13.
  • Exposure time Photoconductor (parts by weight): (seconds) None 180 Naphthalene (0.064) ca. 20 Hydroquinonedimethyl ether (0.070) 30 N-ethylcarbazole (0.097) 10 Anthracene (0.090) 5 Chrysene (0.114) 15 Pyrene (0.10) -1 10 o-Dianisidine (0.122) 5 2,6-dimethyl-naphthalene (0.078) 0 Hexamethylbenzene (0.081) 2,2'-dinaphthylamine (0.134) 1-2 2,5-bis-(4'-diethylaminophenyl)-1,3,4-oxdiazole (0.182) 1 2,3,5-triphenylpyrrole (0.153) 4 EXAMPLE 17 10.6 parts by weight of 2-acetyl fluorene and 12 parts by weight of afterchlorinated polyvinyl chloride are dissolved in parts of toluene and sufficient butanol to
  • Exposure time Photoconductor (parts by weight): (seconds) None 1 180 o-Dianisidine (0.120) 30 2,5-bis-(4' diethylaminophenyl) -1,3,4-oxdiazole 1 No image obtained,
  • EXAMPLE 18 44 parts by weight of 9 acetyl-anthracene and 48 parts by weight of afterchlorinatcd polyvinyl chloride are dissolved in 700 parts by volume of solution. To 50 parts by volume of the resulting stock solution, one of the photoconductors of the following table is added. This solu-. tion is applied to an aluminum foil and further proc essed as described in Example 1. The light source and the distance thereof was the same as in Example 13.
  • Exposure time Photoconductor (parts by weight): (seconds) None 1 180 Hydroquinonedimethyl ether (0.069) 30 N-ethyl carbazole (0.097) 60 Anthracene (0.089) 60 Hexamethylbenzene (0.081) 30 1 Image with heavy background.
  • EXAMPLE 19 46.2 parts by weight of pyrene-3-aldehyde and 50 parts by weight of afterchlorinated polyvinyl chloride are dissolved in 670 parts by volume of toluene and sufficient butanol to make up 1000 parts by volume of solution. To 50 parts by volume of the resulting stock solution one of the photoconductors of the following table is added. The solution is applied to an aluminum foil and further processed as described in Example 1. The light source 15 and the distance of the light source were the same as in Example 13.
  • Exposure time Photoconductor (parts by weight): (seconds) None 30 Naphthalene (0.064) 20 Hydroquinonedimethyl ether (0.070) 20. N-ethylcarbazole (0.10) 10 Anthracene (0.090) 2O Chrysene (0.114) 20 Pyrene (0.10) 20 Hexamethylbenzene (0.080) 20 2,2'-dinaphthylamine (0.135) 15 2,5-bis-(4'-diethylaminophenyl)-l,3,4-oxdiazole 2,3,5-triphenylpyrrole (0.150) 20 EXAMPLE 20 13.1 parts by weight of 1,4,5-trinitronaphthalene and 15 parts by weight of afterehlorinated polyvinyl chloride were dissolved in 180 parts by volume of toluene and sufiicient butanone to make up 250 parts by volume. To 50 parts of the resulting stock solution, one of the photoconductors of the following table is
  • Exposure time Photoconductor (parts by weight): (seconds) None 1 180 N-ethylcarbazole (0.10) 30 Anthracene (0.09) 30 o-Dianisidine (0.12) 2,5-bis-(4-diethylaminophenyl)-1,3,4-oxdiazole 1 Image with heavy background.
  • a sensitized photoconductive layer comprising at least one solid, non-resinous, substantially colorless electron-acceptor, and a compound having the formula in which R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; the layer contain-ing the photoconductor and the electron-acceptor in proportions ranging from substantially less than equal amounts to a substantial excess of the photoconductor with respect to the electron-acceptor and from substantially less than equal amounts to a substantial excess of the electron-acceptor with respect to the photoconductor,
  • a sensitized photoconductive layer comprising at least one solid, non-resinous, substantially colorless electron-acceptor, and a compound having the formula I in which R and R are fused ring ortho-arylene groups,
  • R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from a'bout 0.1 to about 300 moles of the electron-acceptor per 1000 moles of photoconductor.
  • a sensitized photoconductive layer comprising, at least
  • At least one solid, non-resinous, substantially colorless electron-acceptor and a compound having the formula in which R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 0.1 to about 300 moles of the photoconductor per 1000 moles of the electron-acceptor.
  • a sensitized photoconductive layer comprising at least one solid, non-resinous, substantially colorless electron-acceptor, and a compound having the formula in which R and R are fused ring ortho-arylene groups,
  • R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 1 to about 50 moles of the electronacceptor per 1000 moles of the photoconductor.
  • a sensitized photoconductive layer comprising at least one solid, non-resinous, substantially colorless electron-acceptor, and a compound having the formula in which R and R are fused ring ortho-arylene groups,
  • R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 1 to about 50 moles of the photo-.
  • a layer according to claim 1 in which the electronacceptor is 2,4,7-trinitrofluorenone.
  • a photographic reproduction process which comprises exposing .an electrostatically charged, supported, photoconductive insulating layer to light under a master and developing the resulting image with an electroscopic material, the photoconductive layer comprising at least one solid, non-resinous, substantially colorless electronacceptor and a compound having the formula in which R and R are fused ring 'ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl.
  • a photographic reproduction process which comprises exposing an electrostatically charged, supported, photoconductive insulating layer to light under a master and developing the resulting image with an electroscopic material, the photoconductive layer comprising at least one solid, non-resinous, substantially colorless electronacceptor and a compound having the formula in which R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; the layer containing the photoconductor and the electron-acceptor in proportions ranging from substantially less than equal amounts to a substantial excess of the photoconductor with respect to the electron-acceptor and from substantially less than equal amounts to a substantial excess of the elect-romacceptor with respect to the photoconductor.
  • a photographic reproduction process which comprises exposing an electrostatical'ly charged, supported, photoconductive insulating layer to light under a master and developing the resulting image with an electroscopic material, the photoconductive layer comprising at least one solid, non-resinous, substantially colorless electronacceptor and a compound having the formula in which 'R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 0.1 to about 300 moles of the electronacceptor per 1000 moles of photoconductor.
  • a photographic reproduction process which comprises exposing an electrostatically charged, supported, photoconductive insulating layer to light under a master and developing the resulting image with an electroscopic material, the photoconductive layer comprising at least one solid, nonresinous, substantially colorless electronacceptor and a compound having the formula in which R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 0.1 to about 300 moles of the photocond-uctor per 1000 moles of the electron-acceptor.
  • a photographic reproduction process which comprises exposing an electrostatical'ly charged, supported, photoconductive insulating layer to light under a master and developing the resulting image with an electroscopic material, the photoconductive layer comprising at least one solid, nonresinous, substantially colorless electronacceptor and a compound having the formula in which R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 1 to about 50 moles of the electronacceptor per 1000 moles of the photoconductor.
  • a photo-graphic reproduction process which comprises exposing an electrostatically charged, supported, photoconductive insulating layer to light under a master and developing the resulting image with an electroscopic material, the photoconductive layer comprising at least one solid, non-resinous, substantially colorless electronacceptor and a compound having the formula in which R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 1 to about 50 moles of the photoconductor per 1000 moles of the electron-acceptor.

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Description

United States Patent 3,287,119 PROCESS FOR THE SENSITIZATION 0F PHOTOCONDUCTORS Helmut Hoegl, Geneva, Switzerland, assignor, by mesne assignments, to Azoplate Corporation, Murray Hill NJ.
No Di'awing. Original application July 24, 1961, Ser. No. 125,984. Divided and this application Jan. 18, 1965, Ser. No. 426,358 Claims priority, application Germany, May 29, 1959,
K 37,853; July 28, 1960, K 41,311 30 Claims. (Cl. 96-1.5)
This application is a division of copending application Serial No. 125,984, filed July 24, 1961, now abandoned,
which, in turn, is a continuation-in-part of application Serial No. 30,752, filed May 23, '1960, and also now abandoned.
Electrophotographic material normally consists of a support on which there is a photoconductive substance, this coating being provided in the absence of light with an electrostatic charge. Then, the material is exposed to light behind a master, or an episcopic image is projected thereon, so that an electrostatic image is formed which corresponds to the master. This image is developed by being briefly contacted with a resin powder, whereupon a visible image is formed which is fixed by heating or by the action of solvents. In this way, an image of the master which is resistant to abrasion is obtained electrophotographically.
In the electrophotographic process as described an increase in the sensitivity of the photoconductive coatings has already been attempted by the addition of organic dyestuflfs, e.g. triphenylmethane, xanthene, phthalein, thiazine and acridine dyestufis, to the photoconductors.
The absorption maxima of the organic photoconductors are mostly in the ultra-violet region of the spectrum. The-addition of these dyestuft' sensitizers achieves the result that the photoconductors become sensitive to visible light. Generally, the dyestuflf sensitizers cause a displacement of the available sensitivity from the ultraviolet region to the visible region. With increased addition of dyestuif sensitizer, the sensitivity to visible light at first increases rapidly, but further additions give an increase in sensitivity which is much less than would be expected, and still further additions finally give no appreciable increase in sensitivity. The dyestulf sensitizers have the disadvantage that they color the coating considerably. In practice, the maximum achievable increase in sensitivity can seldom be utilized because then the photoconductor coatings have an intensity of color that is undesirable. Colorless or practically colorless photoconductor coatings are desired, since colored material can be employed only in special cases. If additions of dyestuff sensitizers are such as not to adversely afiect the coloring of the coating for practical purposes, the sensitizing effect often does not meet the demands of general usage. Further, the dyestutf sensitizers have the disadvantage that they bleach out relatively quickly so that their sensitizing action tends to be lost during the storage of the electrophotographic material.
A process for the sensitization of photoconductor coatings has now been found in which organic substances, containing polarizing residues and being capable of serving as electron-acceptors in a molecule complex, having low molecular weight, i.e. being non-resinous, being colorless or of pale color and having a melting point above room temperature, are added to the photoconductor coatings.
Substances which are primarily of interest as photoconductor coatings in accordance with the present process are those which can serve as electron donors in molecule complexes of the donor/acceptor type (known as Er-complex) and contain at least one aromatic or heterocyclic ring, which may be substituted. Such photoconductors include aromatic hydrocarbons such as naphthalene, anthracene, benzanthrene, chrysene, p-diphenylbenzene, diphenyl anthracene, p-terphenyl, p-quaterphenyl, sexiphenyl; heterocycles such as N-alkyl carbazole, thiodiphenylamine, oxadiazoles, e.g., 2,5-bis-(p-amiuophenyl)-l,3,4-oxadiazole and its N-alkyl and N-acyl derivatives; triazoles such as 2,5 bis-(p-aminophenyl)- l,3 ,4-triazole and its N-alkyl and N-acyl derivatives; imidazolones and imidazolthiones, e.g., 1,3,4,5-tetraphenyl-imidazolone-Z and 1,3,4,5-tetraphenyl-imidazoltlnone-Z; N-aryl-pyrazolines, e.g. 1,3,5-triphenyl-pyrazoline; hydrated imidazoles, e.g., 1,3-diphenyl-tetrahydroimidazole; oxazole derivates such as 2,5-diphenyloxazole-2- p-dimethylamino-4,S-diphenyloxazole; thiazole derivatives such as 2-p-dia1kylaminophenyLmethyl-benzthiazole; as also thefollowing:
Oxazoles and imidazoles described in German patent application K 35,586 Iva/57b, filed Aug. 22, '1958. Acylhydrazones described in German patent application K 36,517 Iva/57b, filed Dec. 19, 1958. 2,2,4-triazines described in Germanpatent application K 36,651 Iva/57b, filed Ian. 7, 1959.
Metal compounds of mercapto-benzthiazole, mercaptobenzoxazole and mercapto-benzimidazole described in German patent application K 37,508 IVa/57b, filed Apr. 18, 1959.
Imidazoles described in German patent application K 37,435 Iva/57b, filed Apr. 9, 1959. Triphenylamines described in German patent application K 37,436 Iva/57b, filed Apr. 9, 1959.
Furans, thiophenes and pyrroles described in German patent application K 37,423 IV a/ 57b, filed Apr. 8, 1959;
Amino compounds with multinuclear heterocyclic and multinuclear aromatic ring system described in Ger- 111198511; patent application K 37,437 IVa/57b, filed Apr. 9,
Azomethines described in German patent application K 29,270 IVa/57b, filed July 4, 1956.
Molecule complexes are defined in H. A. Staabs Einfuhrung in die theoretische organische' Chemie (Introduction to Theoretical Organic Chemistry), Verlag Chemie, 1959, pp. 694-707, and by L. I. Andrews, Chemical Review, vol. 54, 1954, pp. 713-777. In particular, the donor/ acceptor complex (r-complexes) and charge-transfer complexes which are formed from an electron-acceptor and an electron-donor are included. In the present case, the photoconductors are the electrondonors and the substances here called activatorsto dis tinguish them from the dyestutf sensitizers-are the electron-acceptors. The electron-donors have a low ionization energy and have a tendency to give up electrons. They are bases in the sense of the definition of acids and bases given by G. N. Lewis (H. A. Staab, as above, p. 600). The electron-donors primarily concerned in the present case are the photoconductors described above. These photoconductors consist of aromatic or heterocyclic systems containing a plurality of fused rings, or, alter natively, single rings having substituents which facilitate further electrophilic substitution of the aromatic ring, socalled electron-repellent substituents, as described by L. F. and M. F ieser, Lehrbuch der organischen Ohemie" (Textbook of Organic Chemist y) Verlag Chemie, 1954, p. 651, Table I. These are, in particular, saturated groups, e.g., alkyl groups such as methyl, ethyl, and propyl; alkoxy groups such as methoxy, ethoxy and propoxy; carbalkoxy groups such as carbmethoxy, carbethoxy and carbpropoxy; hydroxyl groups, amino groups and dialkylamino groups such as dimethylamino, diethylamino and dipropylamino.
The activators in accordance with the invention, which are electron-acceptors, are compounds with a high electron-aflinity and have a tendency to take up electrons. They are acids in the sense of Lewis definition. Such properties are possessed by substances having strongly polarizing residues or groupings such as cyano and nitro groups, halogens such as fluorine, chlorine, bromine and iodine; ketone groups, ester groups, acid anhydride groups, acid groups such as, carboxyl groups or the quinone grouping. Strongly polarizing electron-attracting groups of this type are described by L. F. and M. Fieser in the Lehrbuch der organischen Chemie, Verlag Chemie, 1954, p, 651, Table I. .Of these substances with amelting point above room temperature (25 C.) are preferable, i.e. solid substances, because these impart a particularly long shelf life to the photoconductive coatings as a result of their low vapor pressure. Substances which are rather deeply colored such as quinones can be used, but those that are colorless or only weak in color are preferable. Their absorption maximum should preferably be in the ultra-violet region of the spectrum, i.e. below 4,500 A. Further, the activator substances in accordance with the present process should be of lower molecular weight, i.e. between about 50 and 5000, preferably between about 100 and 1000, because with activators of lower molecular weight it is possible for reproducible results to be obtained insofar as sensitivity is concerned. Also, the sensitivity remains constant over rather long periods, since substances of lower molecular weight, unlike those of high molecular weight, undergo hardly any change during storage. The following are examples of such substances:
2-bromo-5-nitro-benzoic acid o-Chloronltrobenzene. 2-brom0benz0ic acid Chloracetophenone. Z-chloro-toluene-t-sulphonic acid.-- 2-chlorocinnamic acid. Chloromaleic anhydride 9-chloroacridine 2-chloro-4-nitro-1-benzoic acid. B-chloroacridine 2-chloro-5-nitro-1-benzoic acid. 6-c%0rt;gltrobenzene-5-sulpho- 3chloro-6-nitro-1-benzcic acid.
or e. 1 i-chloro-ii-nitro-l-benzoic acid-.-- Mucochloric acid. 4-chloro-2-hydroxy-benzoic'aci Mucobromic acid. kchloro-l-phenol-Zt-sulphonic aci Styrenedibromide. 2-chloro-3-nitro-1-t0luene-5-sul- Tetrabromo xylene.
phonic acid. 4-cizlorq3-niigo-benzene-phos- B-Trichlorolactic acid nitrile.
p omc ac Dibromosuccinic acids. Tripheuylchloromethane. 2 4-dichlorobenz0ic acid.-. Tetrachlorophthalic acid. Dibromomaleic anhydride Tetrabromophthalic acid. 9,10-dibromoanthracene Tetraiodophthalic acid. 1,5-dichloronaphthalene-.- Tetrachlorophthalic anhydride. 1,3-dichloronaphthalene Tetrabrornophthalic anhydride. 2,4-dinitro-l-chloronaphthalene--- Tetraiodophthalic anhydride. 3,4-dieh1oro-nitrobenzene Tetzl actilcrophthalic acid monoe y es er. 2,4-dich1oro-benzisatin Tetrabromophthalic acid monoethylester. 2,6-dichloro-benzaldehyde Tetraiodophthalic acid monoethyiester. Hexabromonaphthalle anhydride Iodoiorm. bz-l-cyano-benzanthrone Fumaric acid dinitrile. Cyan acetic acid Tetracyanethylene. acyanocinnamic acid s-Tricyano-benzene. 1,5-dicyanonaphthalenc 3,5dinitrobcnzoic acid 2,4-dinitro-l-chloronaphthalene. 3,5-dinitrosalicylic acid 1,4-dinitro-naphthalcne. 2,4-dinitro-1-benzoic acid 1,5-dinitro-naphthalcne. 2,4-dinitro-1-t01uene-6sulionic acid- 1,8-dinitronaphthalcne. 2,6-rlia1itro-1-phenol-4-sulphonic 2-nitrcbenzoic acid.
ac 1,3-dinitro-benzene 3-nitrobenzoic acid.
' 4-nitrobenzoic acid.
3-nitro-4-ethoxy-benzoic acid. 3-nitro-2-cresol-5-sulphonic acid.
6-nitro4-methy1-l-phenoi-2-su1- B-nitrobarbituric acid.
phonic acid. Z-nitrobenzenesul hinic acid 4-nitro-acenaphthene. 3-nitro-2-hydroxy -1-benzoic acid 4-nitro-benzaldehyde. 2-nitro-1-phen0l-4-sulphonic acid 4-nltro-phenol. a-nitro-N-butyl-carbazole Picryl chloride. 4-nitrobiphenyl 2,4,7-trinitro-fluorenone. Tetranitrofluorenone s-Trinitro-benzene. 2,4,6-trinitro-anisole- Anthraquinona; l-chloro-Z-methyl-anthraquinone. Anthraquinone-Zcarboxylic acid--- Duroquinone. Anthraquinone-2-a1dehyde 2,6-dichloroquinone. antliiliiaiquinoneisulphonic acid 1,5-diphenoxy-anthraquinone.
an e. Anthgaquinone-ZJ-disulphonic 2,7-dinltr0-anthraquinone.
Anthraquinone-2,7-disulphonic 1,5-dich1oro-anthraquinone.
acid bis-anilide. Anthraquinone-Z-sulphonic acid 1,4-dimethyl-anthraquinone. i
dimethylamide. Acenaphthenequinone 2,5-dichloro-benzoquinonc.
Anthraquinone-2-sulphonic acid methylarnide.
Acenaphthenequinone dichloride- Benzoquinone-l l-methyli-chloro-anthraquinoue.
knitro-l-phenol-iasulphonic acid. Picric acid.
1,2-benzanthraquinone Z-methylanthraquinone.
Bromanil Naphthoquinone-LZ.
1-chloro-4-nitro-anthraquinone- Naphth0qu1none-1,4.
Chloranil Pentacenequmone.
l-chlor-anthraquinone Tetracene-7,12-qumone.
Chrysenequinone. 1,4-toluquinone.
Thymcquinone -2,5,7,IO-tetrachloropyrenequlnone.
2,3-dichloro-naphthoquinone-1,4.
1,5-dich1oro-anthraquinone.
The quantity of the solid, non-resinous, substantially colorless electron-acceptors (activators) which is; best incorporated in the photoconductive coating to be sensitized is easily established by simple experiments. The
photoconductive coating containing at least one photoconductor and at least one solid, non-resinous, substani tially colorless, electron-acceptor, should contain the photoconductor and electron-acceptor in proportions ranging from substantially less than, equal amounts to a substantial excess of the photoconductor with respect to the: 1 electron-acceptor. The optimum of the proportions 1 varies somewhat according to the substance used. Generally, minor amounts are used, i.e. from about 0.1 to. about 300 moles, preferably from about 1 to about150 conductor and at least one solid, non-resinous, substan-.
tially colorless electron-acceptor, it isalso very useful to. have present the photoconductor and the electron-ac-.
ceptor in proportions ranging from substantially less than equal amounts to a substantial excess of the electronacceptor with respect to the photoconductor. Theseproportions in which minor amounts of the photocon-v ductor are added to the activator vary according to the substance used; however, in general, amounts from about 0.1 to about 300 moles, preferably from about 1 to about 50 moles photoconductor per 1000 moles activator are used. In some cases, it is also possible to use more 1 than 300 moles photoconductor or activator per .1000 moles activator or photoconductor, respectively, butby exceeding the above range the dark decay of the mixture usually increases, and in such cases coatings made 1 therefrom are inferior.
tors such as naphthalene, whose initial sensitivity is very slight, to be given adequate sensitivity for the production of satisfactory images by electrophotographic processes.
Furthermore, by addition of minor amounts of photoconductors to activators, photoconductive mixtures are obtained which have photoconductivity much higher, than could be expected from the amount of the photoconducfor added to the activator. photoconductivity may be obtained by the addition of dyestuff sensitizers in the same amounts as in the photoconductor-activator mixtures in which the photoconductor, is present in a major amount.
moles of electron-acceptor per- 1000 moles of photoconi ductor. Alternatively, it has also been found that in the photoconductive coatings containing at least one photo- Mixtures of several photoconductors and activator sub 1 stances may also be used. Moreover, in addition to these sensitivity, particularly in the ultra-violet region, and,
to visible light by a very small addition of dyestufi,
A further increase in the The coatings are treated in other respects in accordance with the known processes of electrophotography, i.e. the photoconductor substances are used in the form of thin, coherent homogeneous coatings on a supporting material. The materials used as supports are primarily metals, such as aluminum, zinc, and copper; cellulose products, such as paper and cellulose hydrate; plastics, such as polyvinyl alcohol, polyamides, and polyurethanes. Other plastics, such as cellulose acetate and cellulose butyrate, especially in a partially saponified form, polyesters, polycarbonates, and polyolefins, if they are covered with an electroconductive layer or if they are converted into materials which have the above-mentioned specific conductivity, e. g. by chemical treatment or by introduction of materials which render them electrically conductive, can also be used, as well as glass plates. In general, materials are suitable the specific resistance of which is less than ohm-cm, preferably less than 10 ohm-cm.
If paper is used as the supporting material, it is preferably pretreated against the penetration of coating solutions, e.g., it can be treated with a solution of methyl cellulose or polyvinyl alcohol in water or with a solution of an interpolymer of acrylic acid methyl ester and acrylonitrile in a mixture of acetone and methylethyl ketone, or with solutions of polyamides in aqueous alcohols or with dispersions of such substances.
For the preparation of the electrophotographic material, the photoconductive compounds are preferably dissolved in organic solvents such as benzene, acetone, methylene chloride or ethyleneglycol monomethylether or other organic solvents or in mixtures of such solvents, and resins and the activators-and possibly also the dyestufi sensitizers-are advantageously added thereto. These solutions are coated upon the supporting material in the normal manner, e.g., by immersion processes, painting or roller application or by spraying. The material is then heated so that the solvent will be removed.
A number of the compounds in question can be applied together to the supporting material or the compounds can be applied in association with other photoconductive sub stances.
Further, it is often advantageous for the photoconductor substances to be applied to the supporting material in association with one or more binders, e.g., resins. Resins primarily of interest as additions to the photoconductor coatings include natural resins such as balsam resins, colophony and shellac, synthetic resins such as coumarone resins and indene resins, processed natural substances such as cellulose ethers; polymers such as vinyl polymers, e.g. polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl acetals, polyvinyl alcohol, polyvinyl ethers, polyacrylic and polymethacrylic acid esters, isobutylene and chlorinated rubber.
If the photoconductive compounds in accordance with the invention are used in association with the resins described above, the proportion of resin to photoconductor substance can vary very greatly. Mixtures of from two parts of resin and one part of photoconductor substance to two parts of photoconductor substance and one part of resin are .to be preferred. Mixtures of the two substances in equal parts by weight are particularly favorable.
For the displacement of sensitivity from the ultra-violet to the visible range of the spectrum, dyestufi sensitizers can be used in addition to the activators. Even very small additions of sensitizer, e.g., less than 0.01 percent, give good results. In general, however, 0.01 to 5 percent, and preferably 0.1 to 3 percent of dyestufi sensitizer is added to the photoconductor coatings. The addition of larger quantities is possible but in general is not accompanied by any considerable increase in sensitivity.
Some examples are given below of dyestufi sensitizers which may be used with good results, and some with very good results. They are taken from Schultz Farbstofitabellen (7th edition, 1931, 1st vol.):
Triarylmet-hane dyestuffs such as Brilliant Green (No. 760, p. 314), Victoria Blue B (No. 822, p. 347 Methyl Violet (No. 783, p. 327), Crystal Violet (No. 785, p. 329), Acid Violet 6B (No. 831, p. 351); xanthcne dyestufis, namely rhodamines, such as Rhod-amine B (No. 864, p. 365), Rhodamine 66 (No. 866, p. 366),Rhodamine G Extra (No. 865, p. 366), Sulphorhodamine B (No. 863, p. 364) and Fast Acid Eosin G (No. 870, p. 368), as also phthaleins such as Eosin S (No. 883, p. 375), Eosin A (No. 881, p. 374), Erythrosin (No. 886, p. 376), Phloxin (No. 890, p. 378), Bengal Rose (No. 889, p.. 378), and Fluorescein (No. 880, p. 373); thiazine dyestufis such as Methylene Blue (No. 1038, p. 449); acridine dyestuffs such as Acridine Yellow (No. 901, p. 383), Acridine Orange (No. 908, p. 387) and Trypaflavine (No. 906, -p. 386); quinoline dyestuffs such as Pinacyanol (No. 924, p. 396) and Cryptocyanine '(No. 927,. p; 397 cyanine dyestuffs, e.g., Cyanine (No. 921, p. 394) and chlorophyll.
For the production of copies with the electrocopying material, the photoconductive coating is charged by means of, for example, a corona discharge with a charging apparatus maintained at 6000-7000 volts- The electro-copying material is then exposed to light in contact with a master. Alternatively, an episcopic or diascopic image is projected thereon. An electrostatic image correspending to the master is thus produced on thematerial. This invisible image is developed by contact with adeveloper consisting of carrier and toner. The carriers used may be, for example, tiny glass balls, iron powder or tiny plastic balls. The toner consists of a resin-carbon black mixture or a pigmented resin. The toner is used in a grain size of 1 to The developer may also consist of a resin or pigment suspended in a non-conductive liquid in which resins may be dissolved. The image that is made visible by development is then fixed, e.g., by heating with an infra-red radiator to 100-170 0., preferably -150 C. or by treatment with solvents such as trichloroethylene, carbon tetrachloride or ethyl alcohol, or steam. Images corresponding to the master characterized by good contrast effect are obtained.
If transparent supporting material is used, the electrophotographic images can also be used as masters for the plrl'oduction of further copies on any type of light-sensitive s eets.
If translucent supports are used for photoconductive layers such as are provided by the invention, reflex images can be produced also.
The application of the activators in accordance with the present process is not restricted to electrophotographic coatings, but can extend to other devices containing photoconductors, e.g., photoelectric cells, photoresistances, sensing heads or camera tubes and electroluminescent apparatus.
The invention will be further illustrated by reference to the following specific examples:
EXAMPLE 1 A solution containing 26 parts by weight of polyvinyl acetate (e.g., Mowilith 50), 25.6 parts by weight of naphthalene, 0.0415 part by weight of 2,3,7-trinitrofluorenone and 800 parts by volume of toluene is apnliedby means of a coating device to an aluminum foil. After the coating has dried, direct images are produced thereon by the electrophotographic process in the following manner: the coated foil is given a negative electric charge by corona discharge, exposed behind a master to the light of a high-pressure mercury vapor lamp watts, at a distance of 30 cm.) for about 10 seconds and then dusted over with a developer.
The developer consists of tiny glass balls and a mixture of resin and carbon black which has been melted together.
and then finely divided. A developer of this sort consists of, e.g., 100 parts by weight of tiny glass balls (grain size: 100-400,11. approx.) and a toner (grain size: 20-50 approx.). The toner is prepared by melting together'30 parts by weight of Polystyrol LG, 30 parts by weight of modified maleic acid resin (Beckacite K 105) and 3 parts by weight of Peerless Black Russ 552. The melt 8 7 EXAMPLE 5 A solution of 26 parts by weight of polyvinyl acetate,:
21.6 parts by weight of1,5-diethoxynaphthalene and 0.258 part by weight of 1,2-benzanthraquinone in 800 Without the hexabromonaphthalic anhydride addition, an exposure of as much as 30 seconds gives an image which contains background.
EXAMPLE 4 A solution'containing 18 parts by weight of polyvinyl acetate, 18.2 parts by weight of 2,4-bis-(4'-diethylamino phenyl)-1,3,4-triazole and 0.130 part by weight of tetrachlorophthalic anhydride to 500 parts by volume of toluene is applied to an aluminum foil and further procedure is as described in Example 1. The exposure time with a l-watt incandescent lamp is 2 seconds.
Without the tetrachlorophthalic anhydride addition, the image obtained after an exposure of 1 minute is not free of background.
Explanations on Table A is then ground and screened. The finely divided resin adparts by volume of toluene is applied to paperand the hares t0 the Pa of f t not struck by during material is further processed as described in Example 1. i exposur? i a Posmve Lmage of the master ecomes The exposure time (125-watt high-pressure mercury vapor visible. It is shghtly heated and thereby fixed. lamp) is 20 seconds If. not to h g i Without the 1,2-benzanthraqninone addition, the copy descl'lbed above, even an f": 0 two es W1 still has considerable background after an exposure of 80 not produce an electrophotographic image. Seconds EXAMPLE 2 EXAMPLE 6 p 26 parts by weight of polyvinyl acetate 166 parts by 26 parts by weight of polyvinyl acetate, 17.0 parts weight of fluorene and 0.3602 part by weight of tetranitroby welaht 0f Pllfillanthmne d 9- P y Welght 0f fluorenone are dissolved in 800 parts byvolume of toluchlofaflll are (1185011160 g t er 1n 300 parts -by volume ene. This solution is applied to an aluminum foil and of toluene- 5011111011 18 PP t0 P Y further procedure is as described in Example Exporoughened aluminum foil and then the material ls fursum time if a 125 watt higbpressure mercury Vapor lamp ther processed as described In Example 1. If the mate-- is used, is 10 sticonds. t rial is exposed to a 125-watt high-pressure mercury vapor Without the'tetranitrofiuorenone addition, the images lamp, an exposureffi 9 seconds Elves an Image free of obtained even after an exposure of two minutes are not backgrqund e f Whereas wlthout the free of bakgmund, Le the expose-d parts are not f ll chloraml addition there is heavy background even after discharged and'therefore retain a certain amount of dean exposure of one mmute-t veloper. EXAMPLE 7 EXAMPLE 3 A solution containing 26 parts by weight of polyvinyl A solution of 26 parts by weight of polyvinyl acetate, acetate, 24.4 parts by weight of o-dianisidine and 0.0256 17.8 parts by weight of anthracene and 0.3357 part by part by weight of dibromomaleicanhydride in 800 parts weight of hexabromonaphthalic anhydride in 800 parts by volume of toluene is applied to an aluminum foil and by volume of toluene is applied to aluminum and further the material is further processed as described in Examprocedure is, as described in Example 1. With a 125-watt ple 1. The exposure time (125-watt high-pressure merhigh-pressure mercury vapor lamp, the exposure time is cury vapor lamp) is 2 seconds. Without the dibromo- 4 seconds. maleic anhydride addition, it is 10 seconds.
TABLE A No. A B C D E 1 P1ln1 tt,10 t(1 8 12 2 "if; y ace 8 par 5 8 Anthraqulnone, 0.08 30 52:? (ca) 3 8 Anthraqulnone, 0.17 20 see. (b). 4 8 Anthmquinone, 0 25 20 see. (b). 8 0.001 sec. (b). s 0. 005 60sec. (b). 7 8 0.010 60sec. (b). 8 8 0.030 90sec. (b). 8 0.050 90 see. (b). 8 Anthraquinone, 0.17 0. 001 20 see. (b). n g dn 0.010 20sec. (b). g dn 0.50 20sec. (b). 13--- 8 240 sec. (8). 14 8 Anthraqulnone, 0.25 180 sec. (3). Cyclized rubber, 10 parts (2). 8 240 see. (a). (ln 8 Anthraquinone, 0.25 30 see. (a). Alter-chlorinated polyvinylchloride, 7parts (3)- 8 10 see. (a). Polyvinylchloride, alterchlorinated, 7parts (3). 8 Anthraquinone, 0.25 part 3 see. Maleic acid resin, 10 parts (4) 8 240 sec. (a). do 8 Anthraquinone, 0.25 part 60 see. (a) Chlorinated rubber, 10 parts (5) 8 20 see. (a). d 8 Anthraquinone, 0.25 part 10 see. (a). Chlorinated rubber, 10 parts (6) 8 20 see. (a). dn 8 Anthraquinone, 0.25 10sec. (9,), dn 8 Libenzanthraquinone, 0.31 part 1-1.5 see. (3). (ln 8 Hexabromouaphthahc anhydride, 0.80 part- 11.5 see. (a). dn 8 2, t,5,7-tetramtrofiuorenone, 0.43 part 1.5 see. (a). 8 Dlbromomalelc anhydride, 0.30 part; 4-6 see. (a). rln 8 Nitrogterephthalic acid-dimcthylester, 0.28 6-8 see. (a).
par 3() rln 8 Tetracyano ethylene, 0.15 part 4-6 see. (a). 31 dn 8 1,3,5-trlnltrobenzene, 0.25 part 1.5-2 see. (a).
Column A: Quantity and kind of binder used. In all cases, the quantities stated were dissolved in 200 parts by volume of toluene.
Column B: Quantity of the photoconductor.
damine B extra).
Column E: Time of exposure, using:
(a) a 250 watt photographic lamp (Philips Photocrescenta Column D: Quantity of dyestufi sensitizer used (Rho- (b) a customary watt incandescent lamp.
In all The tests were carried through under the same experimental conditions, with the exception of the variations stated in the table.
(1) The polyvinyl acetate used was the product commercially available under the registered trademark Mowilith C.
(2) The cyclized rubber usedwas the product commercially available under the registered trademark "Pliolite S-SD.
(3) The afterchlorinated polyvinylchloride used was the product commercially available under the registered trademark Rhenofiex.
(4) The maleic acid resin used was the product commercially available under the designation Alrosat.
(5) The chlorinated rubber used in Table A, col. A, under N0. 21 (5 was the product commercially available under the registered trademark Parlon S-5 cps.
(6) The chlorinated rubber used in Table A, col. A, under N0. 23 (6) was a product commercially available under the registered trademark Pergut 8-40.
The following Table B shows further examples of various photoconductors which were activated,.and the reduction in exposure time caused by the activators:
TABLE B A B C 26 Chloranil Hexabromonaphthalie anhydride 2,4,5,7-t etranitr0fiuorenone Hediagromonaphthalic anhy- 1 e. 2,4,5,7-tetrauitrofluorenone 1,5-dinitr0naphthalene l,4-benzoquinoue Ohloraml 3,5-dinitrosalicylic 301d--. Dibromomaleic anhydride Tetrachlorophthalic anhydride Hexabromonaphthalic anhydride- Picrylehloride 2,4.5,7-tetranitrofluorenone- Chloranil 13.6 hydroquinonedimethylether.
m: PST;
25.6 naphthalene- 26 21.6 1,5-diethoxynaphthalene.
15.4 acenaphthene Dibromomaleic auhydride Hexabromonaphthalic an.hydride Picrylchloride 15.2 acenaphthylene- Hexabrornonaphthalrc anhydride. 2,4,5,7-tetranitrofluorenone Chloranil 1,2-benzanthraquinone- Tetrachlorophthalic anh Picrylchloride 15.4 dlphenyl Chloranll 1 ,2-benzanthraquino Tetrachlorophthalic anh Hexabromonaphthalic anhydrid Picrylchloride Chloranil 24.4 o-dianisidiue 16.6 finorene 1,2-benzanthraquinone Hexabrornonaphthalie anhydride- Plcrylchlon'de 3,5dinitrosalicylic aeid 1,2-benzanthraquin0ne Dibromorualeic anhydride Tetrachlorophthalic auhydride 2,4,5,7-tetranitrofluorenoue Benzoquinone 17.8 anthracene 22.8 chrysene 52 Tetrachlorophthalic anhydride Hexabromonaphthalic auhydride Picrylchloride 2,4,5,7-tetrar1itrofluorenone Benzoqntuone- Chloranil 2,4,5,7-tetranitrofluorenone lA-benzoquinoue Chloranil 3,5-dinitrosalicylie aeid 1.2-benzanthraquinone Dibromornaleie acid anhydri Tetraehlorophthalic anhydride-- Hexabromonaphthalic anhydride Picrylchloride 2,4,5,7-tetranitrofiuorenone 1,2-benzanthraquinone Dibrornomaleic anhydride. 'Ietrachlorophthalic anhydride Hexabromouaphthalic anhydride Picrylchloride 2,4,5,7-tetranltrofiuoreno 16.9 diphenylamlne 26.9 2,2 -dinaphthylamine.
17.8 phenanthrene TABLE B-C0ntinued 19.3 Z-phenyl-indole 26 16.7 carbazole 19.9 thiodiphenylamine--- 25.48 2,4-bis-(4-diethylaminophenyl)-1,3,4- oxadiazole.
18.2 2,4-bis-(4'-diethylaminophenyl)-l,3,+ triazole.
Explanations on Table B The table describes a series of experiments carried through for improving the photoconductivity of organic substances by adding activators.
In Column A the quantity and nature of the substance used is stated. The substances marked with a yielded no electrophotographic images even after an exposure time of several minutes. 7
In Column B the quantity of the binder used is stated. In all of the cases, polyvinyl acetate having a K-value of 50 was used. Binder, photoconductive substance, and activator were dissolved in toluene, coated onto an aluminum foil, and dried.
In Column C the substance used as activator is stated. In all of the cases 1 mol of the activator stated under C was used per moles of the substance stated under A.
In Column D the reduced time of exposure is stated which is required to produce images equal in quality to those produced without the addition of an activator. In those cases where a prolonged exposure of the photoconductor yielded not even a weak image (marked with a the calculation of the reduced time of exposure was based on the longest exposure used for the unactivated photoconductor substance.
- Alternatively, the increase in sensibility obtained by the addition of activating substances may be taken from. a comparison of the degrees of blackening obtained with the activated photoconductive layer and with the unactivated photoconductive layer, under the same customary step wedge (e.g. Kodak No. 2 density strip with color patches).
EXAMPLE 8 A solution containing 20 parts by weight of afterchlorinated'polyvinyl chloride with a content of chlorine from 61.7 to 62.3 percent and K-value from 59 to 62, 18.01 parts by weight of 2,4,5,7-tetranitrofluorenone and 0.216 part by weight of 1,5-diethoxynaphthalene dissolved in a mixture of 450 parts by volume toluene and parts by volume butanone is applied to an aluminum foil. The subsequent procedure is that described in Example 1. The exposure time, with a 100 watt incandescent lamp at a distance of 30 centimeters is 2 seconds.
Without the addition of 1,5-diethoxynaphthalene the exposure time is about 40 seconds.
1 1 In the following table, the exposure times are given, which were obtained when using other hotoconductors instead of the 1,5-diethoxynaphthalene. I Exposure time;
EXAMPLE 9 A solution of 12 parts by Weight of chlorinated rubber (Pergut 8-40), 5.04 parts by weight of 1,3-dinitrobenzone and 0.106 part by weight of anthracene in 150 parts by volume of toluene is applied to a paper foil and the material is further processed as described in Example 1. The exposure time (125 watt high pressure mercury vapor lamp) is 20 seconds. Without the anthracene addition, even after an exposure time of 80 seconds, only traces of animage were obtained. This means that the exposed parts of the coating were not discharged and therefore still attracted developer.
In the following table the exposure times are given, which were obtained, when using other photoconductors instead of the 1,3-dinitrobenzene.
Exposure time (seconds) Photoconductors (parts by weight):
2,2'-dinaphthylamine (0.180)
2,2'-dinaphthylamine, the exposure time is about 10 sec-.
onds.
EXAMPLE 12 To a solution containing 28.6 parts by weight of tetral chlorophthalic acid anhydride and 20 parts by weight of afterchlorinated polyvinyl chloride in a mixture of 150 parts by volume of butanone and 450 parts by volume 1 of toluene, X parts by weight of photoconductor and Y parts by weight of dyestuft sensitizer are added. In the following table, the amounts; of, the hotoconductor and sensitizer are given together with the corresponding exposure times. It is advantageous to dissolve the dyestuff sensitizer in a .small amount of ethyleneglycol monomethyl ether before adding it to the solution. The latter is applied to a paper base material and further processed as described in Example 1. The light source used throughout was a 125-watt high pressure mercury vapor lamp and the distance between this lamp and the mate-.
rial exposed was about 30 centimeters.
Photoconductor X parts Dyestufi sensitizer Y Exposure by weight Parts by weight ime (Seconds) None None ca. 200 0.39 N-ethylcarbazo1e -do 9 Do 0.30 Rhodamine B extra 2-3 0.54 2,2-dinaphthylamine None 4-5 Do 0.30 Rhodamine B extra 2 0.73 2,5-bis-(4'-diethylamino- None -1 4 phenyl)-1,3,4-oxdiazole.
Do 0.30 Rhodamine B extra..-" 1-2 0.025 Basischreinblau 3 G 2 0.015 Brillantgreen extra 3 0.015 Kristallviolet 2 0.015 Methylenb1ue 0. 5 y vinylcarbazole 0.30 Rhodamine B extr 9 Do None 20 EXAMPLE 10 A solution containing 20 parts by weight of the afterchlorinated polyvinyl chloride mentioned in Example 8, 21.02 parts by weight of benzile and 0370 part by weight of benzidine in a mixture of 450 parts by volume of toluene and 150 parts by volume of butanone is applied to an aluminum foil and the material is further processed as described in Example 1. The exposure time (125 watt high pressure mercury vapor lamp at a distance of 30 centimeters) is 10 seconds. Without the addition of the benzidine activator, even after an exposure time of 4 minutes, no electrophotographic image could be obtained.
In the following table, the exposure times are given which were obtained when using hotoconductors other than benzidine.
Exposure time Photoconductors (parts by weight): (seconds) 2,2'-dinaphthylamine (0.540) 20 2,5-bis-(4'-diethylamino-phenyl) 1,3,4 oxdiazole (0.730) 5 Poly-N-vinylcarbazole (0.390) 30 EXAMPLE 11 A solution containing 6.2 parts by weight of afterchlorinated polyvinyl chloride, 3.94 parts by weight of 1,5-dichloronaphthalene and 0.145 part by weight of 2,5-bis- (4'-diethylaminophenyl)-1,3,4-oxdiazole in a mixture of 135 parts by volume of toluene and 45 parts by volume of butanone is applied to a paper base and is further processed as described in Example 1. The exposure time (125 watt high pressure mercury vapor lamp at a distance of 30 centimeters) is 10 seconds. Without the addition of the oxdiazole compound, even after an exposure time of 40 seconds, no image could be obtained. When the oxdiazole compound is replaced by 0.120 part by weight of EXAMPLE 13 A solution is prepared, containing 57.2 parts by weight:
of tetrachlorophthalic acid anhydride and 65 parts by weight of afterchlorinated polyvinyl chloride in 700 parts by volume toluene and sufficient butanone is added to make up 1000 parts by volume. To 50 parts by volume of the resulting stock solution, one of the photoconductors listed below is added, and the solution isapplied to an aluminum foil and further processed as describedin.
Example 1. In the following table, the added photoconductors are indicated, and the corresponding exposure- As the light source, a -watt high times are given. pressure mercury vapor lamp in a distance of about 30 centimeters from the exposed material was used in all instances.
Exposure time 1 Image with heavy background,
13 Photoconductor (parts by Weight) Exposure time Continued (seconds) Phenanthrene (0.089) 60 Phenoxathin (0.100) 10 Stilbene (0.090) 30 2,3,5-triphenylpyrrole (0.153) 10 1,1'-dinaphthylamine (0.134) 30 1,2'-dinaphthylamine (0.134) 30 4'-tolyl-1-naphthylamine (0.116) 60 Z-phenylindole (0.096) 60 Acenaphthene (0.077) 60 Diphenyl (0.077) 120 N-methyldiphenylarnine (0.091) 30 4-hydroxy-diphenylamine (0.092) 30 Phlorglucinediethyl ether (0.091) 120 EXAMPLE 14 57.2 parts by weight of tetrachlorophthalic acid anhydride and 65 parts by weight of polyvinyl acetate are dissolved in sufiicient toluene to make up 1000 parts by volume. To 50 parts by volume of this stock solution, one of the photoconductors listed below is added and the coating solution is applied to an aluminum foil and further processed as described in Example 1. The light source and the distance of the light source from the exposed material were the same as in the foregoing example.
Exposure time (seconds) EXAMPLE 15 29.62 parts by weight of phthalic acid anhydride and 33 parts by weight of afterchlorinated polyvinyl chloride are dissolved in 670 parts by volume of toluene and 330 parts by volume of butanone. To 50 parts by volume of the resulting stock solution, one of the photoconductors listed in the following table is added; these coating solutions are applied to an aluminum foil, and further processed as described in Example 1. The light source and the distance of the light source were the same as in Example 13.
Exposure time Photoconductor (parts by weight): (seconds) None 1 60 N-ethylcarbazole (0.10) 5 Anthracene (0.09) Chrysene (0.114) Pyrene (0.10) 10 2,2'-dinaphthylamine (0.134) 10 2,3,5-triphenylpyr1'ole (0.153) 10 N0 image obtained.
EXAMPLE 16 p 49.2 parts by weight of chloranil and 56 parts by weight of afterchlorinated polyvinyl chloride are dissolved in a mixture of 1170 parts by volume of toluene and parts by volume of butanone. The resulting solution is filled up to 2000 parts by volume with chlorobenzene. To 100 parts by volume of this stock solution, one of the photoconductors listed in the following table is added; the coating solution is applied to an aluminum foil and further processed as described in Example 1. The light source and the distance of the light source were the same as in Example 13.
Exposure time Photoconductor (parts by weight): (seconds) None 180 Naphthalene (0.064) ca. 20 Hydroquinonedimethyl ether (0.070) 30 N-ethylcarbazole (0.097) 10 Anthracene (0.090) 5 Chrysene (0.114) 15 Pyrene (0.10) -1 10 o-Dianisidine (0.122) 5 2,6-dimethyl-naphthalene (0.078) 0 Hexamethylbenzene (0.081) 2,2'-dinaphthylamine (0.134) 1-2 2,5-bis-(4'-diethylaminophenyl)-1,3,4-oxdiazole (0.182) 1 2,3,5-triphenylpyrrole (0.153) 4 EXAMPLE 17 10.6 parts by weight of 2-acetyl fluorene and 12 parts by weight of afterchlorinated polyvinyl chloride are dissolved in parts of toluene and sufficient butanol to make up 250 parts by volume of solution. To 50 parts by volume of this stock solution, one of the photoconductors of the following table is added. The solution is applied to an aluminum foil and further processed as described in Example 1. The light source and the distance of the light source were the same as in Example 13.
Exposure time Photoconductor (parts by weight): (seconds) None 1 180 o-Dianisidine (0.120) 30 2,5-bis-(4' diethylaminophenyl) -1,3,4-oxdiazole 1 No image obtained,
EXAMPLE 18 44 parts by weight of 9 acetyl-anthracene and 48 parts by weight of afterchlorinatcd polyvinyl chloride are dissolved in 700 parts by volume of solution. To 50 parts by volume of the resulting stock solution, one of the photoconductors of the following table is added. This solu-. tion is applied to an aluminum foil and further proc essed as described in Example 1. The light source and the distance thereof was the same as in Example 13.
Exposure time Photoconductor (parts by weight): (seconds) None 1 180 Hydroquinonedimethyl ether (0.069) 30 N-ethyl carbazole (0.097) 60 Anthracene (0.089) 60 Hexamethylbenzene (0.081) 30 1 Image with heavy background.
EXAMPLE 19 46.2 parts by weight of pyrene-3-aldehyde and 50 parts by weight of afterchlorinated polyvinyl chloride are dissolved in 670 parts by volume of toluene and sufficient butanol to make up 1000 parts by volume of solution. To 50 parts by volume of the resulting stock solution one of the photoconductors of the following table is added. The solution is applied to an aluminum foil and further processed as described in Example 1. The light source 15 and the distance of the light source were the same as in Example 13.
Exposure time Photoconductor (parts by weight): (seconds) None 30 Naphthalene (0.064) 20 Hydroquinonedimethyl ether (0.070) 20. N-ethylcarbazole (0.10) 10 Anthracene (0.090) 2O Chrysene (0.114) 20 Pyrene (0.10) 20 Hexamethylbenzene (0.080) 20 2,2'-dinaphthylamine (0.135) 15 2,5-bis-(4'-diethylaminophenyl)-l,3,4-oxdiazole 2,3,5-triphenylpyrrole (0.150) 20 EXAMPLE 20 13.1 parts by weight of 1,4,5-trinitronaphthalene and 15 parts by weight of afterehlorinated polyvinyl chloride were dissolved in 180 parts by volume of toluene and sufiicient butanone to make up 250 parts by volume. To 50 parts of the resulting stock solution, one of the photoconductors of the following table is added in the amount indicated. This solution is applied to an aluminum foil and further processed as described in Example 1. The light source and the distance thereof were the same as in Example 13.
Exposure time Photoconductor (parts by weight): (seconds) None 1 180 N-ethylcarbazole (0.10) 30 Anthracene (0.09) 30 o-Dianisidine (0.12) 2,5-bis-(4-diethylaminophenyl)-1,3,4-oxdiazole 1 Image with heavy background.
It will be obvious to those skilled in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.
What is claimed is:
1. A sensitized photoconductive layer comprising at least one solid, non-resinous, substantially colorless electron-acceptor, and a compound having the formula in which R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; the layer contain-ing the photoconductor and the electron-acceptor in proportions ranging from substantially less than equal amounts to a substantial excess of the photoconductor with respect to the electron-acceptor and from substantially less than equal amounts to a substantial excess of the electron-acceptor with respect to the photoconductor,
16* =3. A sensitized photoconductive layer comprising at least one solid, non-resinous, substantially colorless electron-acceptor, and a compound having the formula I in which R and R are fused ring ortho-arylene groups,
at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from a'bout 0.1 to about 300 moles of the electron-acceptor per 1000 moles of photoconductor.
4. A sensitized photoconductive layer comprising, at
least one solid, non-resinous, substantially colorless electron-acceptor, and a compound having the formula in which R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 0.1 to about 300 moles of the photoconductor per 1000 moles of the electron-acceptor.
5. A sensitized photoconductive layer comprising at least one solid, non-resinous, substantially colorless electron-acceptor, and a compound having the formula in which R and R are fused ring ortho-arylene groups,
at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 1 to about 50 moles of the electronacceptor per 1000 moles of the photoconductor.
6. A sensitized photoconductive layer comprising at least one solid, non-resinous, substantially colorless electron-acceptor, and a compound having the formula in which R and R are fused ring ortho-arylene groups,
at least one of the rings having 'a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 1 to about 50 moles of the photo-.
conductor per 1000 moles of the electron-acceptor.
7. A layer according to claim 1 in which the electronacceptor is 2,4,7-trinitrofluorenone.
8. A layer according to claim 1 in which the elcctronacceptor is tetranitrofluorenone.
9. A layer according to claim 1 in which the electronacceptor is heXabromona-phthalic anhydride.
10. A layer, according to claim 1 in which the electronacceptor is tetrachlorophthalic anhydride.
11. A layer according to claim 1 in which the electronacceptor is 1,2-benzanthraquinone.
12. A layer according to claim 1 in which the electronacceptor is chloranil.
13. A layer according to claim 1 in which the electronacceptor is dibromomaleic anhydride.
14. A layer according to claim '1 including a resin.-
15. A layer according to claim 1 including adyestutf sensitizer.
16. A photographic reproduction process which comprises exposing .an electrostatically charged, supported, photoconductive insulating layer to light under a master and developing the resulting image with an electroscopic material, the photoconductive layer comprising at least one solid, non-resinous, substantially colorless electronacceptor and a compound having the formula in which R and R are fused ring 'ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl.
17. A photographic reproduction process which comprises exposing an electrostatically charged, supported, photoconductive insulating layer to light under a master and developing the resulting image with an electroscopic material, the photoconductive layer comprising at least one solid, non-resinous, substantially colorless electronacceptor and a compound having the formula in which R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; the layer containing the photoconductor and the electron-acceptor in proportions ranging from substantially less than equal amounts to a substantial excess of the photoconductor with respect to the electron-acceptor and from substantially less than equal amounts to a substantial excess of the elect-romacceptor with respect to the photoconductor.
18. A photographic reproduction process which comprises exposing an electrostatical'ly charged, supported, photoconductive insulating layer to light under a master and developing the resulting image with an electroscopic material, the photoconductive layer comprising at least one solid, non-resinous, substantially colorless electronacceptor and a compound having the formula in which 'R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 0.1 to about 300 moles of the electronacceptor per 1000 moles of photoconductor.
19. A photographic reproduction process which comprises exposing an electrostatically charged, supported, photoconductive insulating layer to light under a master and developing the resulting image with an electroscopic material, the photoconductive layer comprising at least one solid, nonresinous, substantially colorless electronacceptor and a compound having the formula in which R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 0.1 to about 300 moles of the photocond-uctor per 1000 moles of the electron-acceptor.
20. A photographic reproduction process which comprises exposing an electrostatical'ly charged, supported, photoconductive insulating layer to light under a master and developing the resulting image with an electroscopic material, the photoconductive layer comprising at least one solid, nonresinous, substantially colorless electronacceptor and a compound having the formula in which R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 1 to about 50 moles of the electronacceptor per 1000 moles of the photoconductor.
21. A photo-graphic reproduction process which comprises exposing an electrostatically charged, supported, photoconductive insulating layer to light under a master and developing the resulting image with an electroscopic material, the photoconductive layer comprising at least one solid, non-resinous, substantially colorless electronacceptor and a compound having the formula in which R and R are fused ring ortho-arylene groups, at least one of the rings having a primary amine group attached thereto, and R is selected from the group consisting of hydrogen and lower alkyl; in proportions ranging from about 1 to about 50 moles of the photoconductor per 1000 moles of the electron-acceptor.
22. A process according to claim 16 in which the electron-acceptor is 2,4,7 -trinitrofluorenone.
23. A process according to claim 16 in which the electron-acceptor is tetranitrofluorenone.
24. A process according to claim 16 in which the electron-acceptor is hexa'b-romonaphthalic anhydride.
25. A process according to claim 16 in which the electron-acceptor is tetrachlorophthalic anhydride.
26. A process according to claim 16 in which the electron-acceptor is 1,2-benzanthraquinone.
27. A process according to claim 16 in which the electron-acceptor is chloranil.
28. A process according to claim 16 in which the electron-acceptor is dibromomaleic anyhdride.
29. A process according to claim 16 in which the layer includes a resin.
30. A process according to claim 16 in which the layer includes a dyestuff sensitizer.
References Cited by the Examiner UNITED STATES PATENTS 3,037,861 6/1962 Hoegl et al. 961 3,113,022 12/1963 Cassiers et a1. 961 3,155,503 11/1964 Cassiers et a1. 961 3,206,306 9/1965 Neuge'bauer et al. 961
OTHER REFERENCES Andrews, Chemical Reviews, 54: 713-777, October 1954.
Czekal'la et al.: Chemical Abstracts 52: 4317b (1957).
Schneider and Compton et al.: Journal of Chemical Physics, vol. 25: 358, 1075-1076 1956.
NORMAN G. TORCHIN, Primary Examiner.
C. E. VAN HORN, Assistant Examiner.

Claims (1)

1. A SENSITIZED PHOTOCONDUCTIVE LAYER COMPRISING AT LEAST ONE SOLID, NON-RESINOUS, SUBSTANTIALLY COLORLESS ELECTRON-ACCEPTOR, AND A COMPOUND HAVING THE FORMULA
US426358A 1961-07-24 1965-01-18 Process for the sensitization of photoconductors Expired - Lifetime US3287119A (en)

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3871880A (en) * 1972-12-01 1975-03-18 Pitney Bowes Inc Organic photoconductor for electrophotography
US3915701A (en) * 1972-12-01 1975-10-28 Pitney Bowes Inc Organic photoconductor for electrophotography
US4069046A (en) * 1971-02-19 1978-01-17 Xerox Corporation Polymerized vinyl carbazoles sensitized by nitro-substituted 9-dicyanomethylene fluorenes
USRE29554E (en) * 1969-06-05 1978-02-28 Addressograph-Multigraph Corporation Organic photoconductive members comprising dicyanomethylene substituted fluorene sensitizers
US4111850A (en) * 1977-02-16 1978-09-05 Amp Incorporated Organic photoconductors and methods
US4302521A (en) * 1979-07-16 1981-11-24 Konishiroku Photo Industry Co., Ltd. Photosensitive element for electrophotography
US4389477A (en) * 1980-04-22 1983-06-21 Fuji Photo Film Co., Ltd. Photoconductive composition sensitized by a thiobarbituric acid derivative
US4413046A (en) * 1981-04-06 1983-11-01 Mita Industrial Co., Ltd. Disazo photoconductor with nitrophthalic anhydride sensitizer
US4415641A (en) * 1981-03-11 1983-11-15 Konishiroku Photo Industry Co., Ltd. Electrophotographic light-sensitive element
US4419429A (en) * 1981-02-09 1983-12-06 Mita Industrial Co., Ltd. Sensitized electrophotographic photosensitive composition

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3037861A (en) * 1957-09-07 1962-06-05 Kalle Ag Electrophotographic reproduction material
US3113022A (en) * 1959-02-26 1963-12-03 Gevaert Photo Prod Nv Electrophotographic process
US3155503A (en) * 1959-02-26 1964-11-03 Gevaert Photo Prod Nv Electrophotographic material
US3206306A (en) * 1959-04-09 1965-09-14 Azoplate Corp Material for electrophotographic purposes

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3037861A (en) * 1957-09-07 1962-06-05 Kalle Ag Electrophotographic reproduction material
US3113022A (en) * 1959-02-26 1963-12-03 Gevaert Photo Prod Nv Electrophotographic process
US3155503A (en) * 1959-02-26 1964-11-03 Gevaert Photo Prod Nv Electrophotographic material
US3206306A (en) * 1959-04-09 1965-09-14 Azoplate Corp Material for electrophotographic purposes

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE29554E (en) * 1969-06-05 1978-02-28 Addressograph-Multigraph Corporation Organic photoconductive members comprising dicyanomethylene substituted fluorene sensitizers
US4069046A (en) * 1971-02-19 1978-01-17 Xerox Corporation Polymerized vinyl carbazoles sensitized by nitro-substituted 9-dicyanomethylene fluorenes
US3871880A (en) * 1972-12-01 1975-03-18 Pitney Bowes Inc Organic photoconductor for electrophotography
US3915701A (en) * 1972-12-01 1975-10-28 Pitney Bowes Inc Organic photoconductor for electrophotography
US4111850A (en) * 1977-02-16 1978-09-05 Amp Incorporated Organic photoconductors and methods
US4302521A (en) * 1979-07-16 1981-11-24 Konishiroku Photo Industry Co., Ltd. Photosensitive element for electrophotography
US4389477A (en) * 1980-04-22 1983-06-21 Fuji Photo Film Co., Ltd. Photoconductive composition sensitized by a thiobarbituric acid derivative
US4419429A (en) * 1981-02-09 1983-12-06 Mita Industrial Co., Ltd. Sensitized electrophotographic photosensitive composition
US4415641A (en) * 1981-03-11 1983-11-15 Konishiroku Photo Industry Co., Ltd. Electrophotographic light-sensitive element
US4413046A (en) * 1981-04-06 1983-11-01 Mita Industrial Co., Ltd. Disazo photoconductor with nitrophthalic anhydride sensitizer

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