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WO1997004363A1 - Toners liquides a orientateur de charge complexe de zirconium et d'aluminium - Google Patents

Toners liquides a orientateur de charge complexe de zirconium et d'aluminium Download PDF

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Publication number
WO1997004363A1
WO1997004363A1 PCT/US1996/008372 US9608372W WO9704363A1 WO 1997004363 A1 WO1997004363 A1 WO 1997004363A1 US 9608372 W US9608372 W US 9608372W WO 9704363 A1 WO9704363 A1 WO 9704363A1
Authority
WO
WIPO (PCT)
Prior art keywords
zirconium
aluminum
soap
charge director
toner
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1996/008372
Other languages
English (en)
Inventor
Mohammed A. Elmasry
Kevin M. Kidnie
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
3M Co
Original Assignee
Minnesota Mining and Manufacturing Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Minnesota Mining and Manufacturing Co filed Critical Minnesota Mining and Manufacturing Co
Publication of WO1997004363A1 publication Critical patent/WO1997004363A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/12—Developers with toner particles in liquid developer mixtures
    • G03G9/135—Developers with toner particles in liquid developer mixtures characterised by stabiliser or charge-controlling agents
    • G03G9/1355—Ionic, organic compounds
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/12—Developers with toner particles in liquid developer mixtures
    • G03G9/135—Developers with toner particles in liquid developer mixtures characterised by stabiliser or charge-controlling agents

Definitions

  • This invention relates liquid toners useful in electrophotography.
  • the invention relates especially to charge directors used in liquid toners.
  • Electrography In electrography and electrophotography a toner is deposited on a charged surface, typically an imagewise charged surface. Electrography generally comprises placing a charge onto selected areas of a dielectric medium with an electrostatic writing stylus or its equivalent to form a charge image, applying toner to the charge image, and fixing the toned image.
  • Electrophotography forms the technical basis for various well known imaging processes, including photocopying and laser printing.
  • a general discussion of color electrophotography is presented in "Electrophotography,” by R. M. Schaffert, Focal Press, London & New York, 1975, pp. 178-190.
  • the basic electrophotographic process involves placing a uniform electrostatic charge on a photoreceptor element, imagewise exposing the photoreceptor element to light thereby dissipating the charge in the exposed areas, developing the resulting electrostatic latent image with a toner, and transferring the toner image from the photoreceptor element to a final substrate, such as paper, either by direct transfer or via an intermediate transfer material.
  • Liquid toners typically comprise toner particles, which usually comprise a polymeric binder and either a pigment or a dye, dispersed in a high resistivity carrier liquid, e.g., IO 9 ohm.cm or more.
  • the liquid toners preferably further include an additive (referred to in this document as a "charge director") for enhancing the charge carried by the toner particles.
  • Each pigment or dye possesses different charge characteristics and the charge directors may function to bring about greater uniformity in the charge characteristics ofthe toner particles. These charge directors frequently may also serve to stabilize the dispersion ofthe toner particles in the carrier liquid.
  • the charge directors associate with the colorant particles by some mechanism, such as complexing, covalent or ionic bonding, adso ⁇ tion on the surface ofthe particles, etc.
  • a variety of materials can be used as charge directors. Illustrative of known charge directors would be the polyoxyethylated alkyl surfactants such as polyoxyethylated alkylamine, polyoxyethylene palmitate, polyoxyethylene stearate, etc.
  • Other useful materials are magnesium and heavier metal soaps of fatty and aromatic acids as described in Beyer, U.S. Pat. No.
  • Useful metal soaps include cobalt naphthenate, magnesium naphthenate and manganese naphthenate, zinc resinate, calcium naphthenate, zinc linoleate, aluminum resinate, isopropyltitanium stearate, aluminum stearate, and others, many of which are also described in U.S. Pat. No. 3,259,581.
  • the amount of such materials used is less than about 2 percent by weight based on the weight of toner.
  • the resinous binder per se can function as the charge control agents, as can the colorant.
  • U.S. Pat. Nos. 4,547,449 and 4,606,989 advance the idea that the level of free charge within the liquid toner as a function ofthe mass of toner particles is important to the efficiency ofthe developing process.
  • the aging ofthe toner was measured by the charge present and related it generally to the zeta potential ofthe individual particles.
  • U.S. Pat. 4,925,766 and 4, 978,598 used polymers having groups capable of forming covalent links with the metal soaps to reduce the amount of free charge directors in the carrier liquid.
  • toner replenishers which are more concentrated dispersions of toner particles in carrier liquid than are toner starter dispersions, must have a different formulation with regard to the amount of charge director than do toner starter dispersions.
  • the present invention provides a novel charge director which is a high molecular weight viscous complex of an aluminum soap and a zirconium soap.
  • the aluminum soap if used alone, is insoluble in the carrier liquid.
  • the resulting complex is fully soluble in aliphatic hydrocarbon liquids, which are frequently used as carrier liquids.
  • This Zirconium/ Aluminum complex associates closely with toner particles and displays very little migration into the carrier liquid.
  • a first embodiment this invention is a charge director which comprises a complex of a zirconium soap and an aluminum soap.
  • This charge director complex has a viscosity of 10-200 cP, preferably 50-100 cP, more preferable 70-90 cP, at a total % solids of 10-15% in a hydrocarbon carrier liquid as measured on a Brookfield Digital Viscometer.
  • the charge director complex may be formed by combining aluminum and zirconium soaps in a nonpolar solvent and heating gradually while stirring.
  • this invention is a liquid toner comprising a dispersion of toner particles with associated Aluminum/Zirconium complex charge director in a carrier liquid. These liquid toners can be used as either toner starter dispersions or toner replenisher solutions because ofthe very low migration of charge director into the carrier liquid.
  • the Aluminum/Zirconium charge director complex of this invention is the reaction product of an aluminum soap which is insoluble in a nonpolar solvent and a zirconium soap.
  • Aluminum soaps useful in this invention may be represented by the general formula Al +3 (OOCR) n X " 3 . n , wherein n is an integer from 1 to 3, preferably 2 or 3, most preferably 3; R is an alkyl group, an alkylene group, or an arylalkyl group of 2 to 30 carbon atoms, preferably 4 to 20 carbon atoms, and X is a monovalent anion.
  • aluminum soaps include, but are not limited to, aluminum palmitates, aluminum stearates, aluminum oleates, aluminum laurates, aluminum octanoates, aluminum hexanoates (e.g. 2-ethyl hexanoate), aluminum decanoates, etc.
  • Aluminum stearates are prefened.
  • X " are OH “ , Cl “ , Br ' , I " , and OR " , where R is as defined above. Hydroxy (OH " ) is the preferred monovalent anion, X.
  • the zirconium soaps useful for the formation ofthe Aluminum/Zirconium charge director complex may be represented by the following formula:
  • Zr(OOCR') m Y " 4 - m wherein m is an integer from 1 to 4, preferably 3 to 4, most preferably 4; R' is an alkyl group, an alkylene group, or an arylalkyl group of 2 to 30 carbon atoms, preferably 4 to 20 carbon atoms, and Y is a monovalent anion.
  • Y is OH “ , OH “ , Cl “ , Br “ , T, and OR' " , where R 1 is as defined above. Hydroxy (OH “ ) is the preferred monovalent anion, Y.
  • zirconium soaps are very sensitive to moisture, they may alternatively be found in the zirconyl soap state which is represented by the formula: (OOCR') 2 .
  • zirconium soaps include, but are not limited to, zirconium palmitates, zirconium stearates, zirconium oleates, zirconium laurates, zirconium octanoates, zirconium hexanoates (e.g. 2-ethyl hexanoate), zirconium decanoates, etc.
  • many ofthe above described soaps are frequently found in associated states which have complex structures that are not easily definable.
  • the charge director complex of this invention may be formed by combining the aluminum and zirconium soaps in a nonpolar solvent and heating gradually to about 80 to 95 °C while stirring.
  • the nonpolar solvent may be an aliphatic or an aromatic hydrocarbon. Examples of suitable aliphatic hydrocarbons include hexane, cyclohexane, iso-octane, heptane, and isododecane, and commercially available mixtures such as IsoparsTM G, H, K, and L (from Exxon Corp.).
  • the complex is a highly viscous material which is soluble in the carrier liquids commonly used in liquid toners. While not wishing to be bound to any theory, the Inventors believe that the Zr/Al complexes are structures that have metal-OH-metal type repeating units. In addition, the high viscosity ofthe complexes may indicate some cross-linking between organic chains.
  • the complex preferably has an zirconium/aluminum weight ratio in the range of 5: 1 to 100: 1, more preferably 10: 1 to 40: 1.
  • the Aluminum/Zirconium charge director complex may advantageously be used in liquid toners which comprise a dispersion of toner particles in carrier liquid.
  • the charge director complex associates with the toner particles and does not show significant migration into the carrier liquid.
  • the toner particles comprise a colorant in a resin or polymeric binder.
  • the carrier liquids used for the liquid toners of this invention may be any known carrier liquid.
  • the carrier liquid is preferably chosen from non-polar liquids, more preferably hydrocarbons, which have a resistivity of at least 10 11 ohm-cm and preferably at least 10 13 ohm-cm, a dielectric constant less than 3.5 and a boiling point in the range 140°C to 220°C.
  • Aliphatic hydrocarbons such as hexane, cyclohexane, iso-octane, heptane, and isododecane, and commercially available mixtures such as IsoparsTM G, H, K, and L (from Exxon Corp.) are suitable.
  • toner particles which comprise a polymeric binder and a colorant. Any binder known for use in toner particles for liquid toners may be used.
  • organosols (sometimes described as amphipathic particles) are preferred. Such organosols are complex molecules having at least one type of polymeric moiety which is solvated by the carrier liquid and at least one type of polymeric moiety which is non-solvated by the carrier liquid. Such organosols are described in U.S. Pat. Nos. 3,753,760; 3,900,412, and 3,991,226.
  • the binder systems disclosed in U.S. Pat. Nos. 4,925,766 and 4,988,602 are preferred.
  • colorants a wide range of pigments and dyes may be used. The only criteria is that they be insoluble in the carrier liquid and be capable of being dispersed to a particle size below about a micrometer in diameter.
  • Suitable pigments include any one ofthe many now known to the art in connection with liquid electrostatographic developers. As is well known, these pigments essentially constitute very fine solid particles having a size in the submicron range and which are opaque en masse. They are insoluble in the liquid system. Any pigments known in the art for use in toners may be used in the toner particles of this invention.
  • Such pigments include but are not limited to phthalocyanines, such as copper phthalocyanine; carbon black; nigrosine dye; Aniline Blue; Chrome Yellow; Dupont Oil Red (from DuPont); Monoline Yellow; Sunfast Blue, Sun Yellow, Sun Red and other pigments available from Sun Chemical Co.; Harmon Quindo Red; Regal 300; Fluorol Yellow 088, Fluorol Green Gold 084, Lumogen Yellow S 0790, Ultramarine Blue, Ultramarine Violet, Ferric Ferrocyanide, and other pigments available from BASF; Malachite Green Oxalate; lamp black; Rose Bengal; Malastral Red; magnetic pigments such as magnetite, ferrites, such as barium ferrite and manganese ferrite, hematite, etc.
  • phthalocyanines such as copper phthalocyanine; carbon black; nigrosine dye; Aniline Blue; Chrome Yellow; Dupont Oil Red (from DuPont); Monoline Yellow; Sunfast Blue, Sun Yellow, Sun Red and other pigments available from Sun Chemical Co.;
  • the pigments are not reactive with the polymeric binder. If dyes are used as colorants they may be incorporated into the polymeric binder as a moiety ofthe organosol molecule or may be a separate molecule which is incorporated into the toner particle by second order or surface adsorption forces. Exemplary ofthe many suitable dyes held to the toner particle by second order or surface adsorption forces are CL Disperse Orange 26, C Disperse Yellow 57, C Disperse Blue 77, CJ. Disperse Blue 73, CJ. Disperse Brown 2, CI. Violet 27, C Basic Blue 35, CI. Basic Violet 15, CL Basic Red 26, CJ. Basic Blue 38, CI. Basic Orange 30, CL Basic Red 24.
  • Exemplary ofthe many suitable dyes which may bond to the polymeric binder and form chromophoric moieties are CL Acid Blue 7, CI. Acid Blue 104, CI. Acid Brown 14, CJ. Acid Yellow 63, CI. Black 26A, CI. Solvent Red 41, CL Solvent Violet 9, CL Solvent Brown 12, CL Solvent Blue 4, CL Solvent Blue 6, CL Solvent Blue 2, CL Solvent Yellow 34, CJ. Solvent Green 1, and CL Solvent Red 49.
  • the liquid toners of this invention preferably have conductivities in the range of 5 to 500 pmho/cm. Preferably, at least 40%, and more preferably at least 80%, ofthe charge is situated on the toner particles.
  • the charge director complex of this invention is highly effective in keeping the charge associated with the toner particles and preventing migration ofthe charge into the carrier liquid. In fact, the charge director complex of this invention is so effective, that there is no need for distinct formulations for starter and replenisher toner solutions. The invention is further illustrated by the following Examples. EXAMPLES
  • a mixture of 90 g of Zirconium Nuxtra 12 (zirconium 2-ethylhexanoate, 12% Zr from Hulls America Inc.), 10 g of Aluminum tristearate, and 262.5 g of Isopar GTM was heated gradually to 95°C while stirring. When the temperature reached 70°C the Aluminum tristearate, which alone is insoluble in IsoparTM G, began to dissolve and the viscosity ofthe reaction mixture increased. The temperature was held at 95°C for about one hour until a homogeneous solution was attained. The solution was then cooled to room temperature. The resulting product did not exhibit any color and appeared clear. The resulting charge director complex had an Zirconium/ Aluminum weight ratio of 23.3: 1.
  • Example 2 The process of example 1 was repeated but this time 85 g of Zirconium
  • Example 3 The process of example 1 was repeated but this time 75 g of Zirconium
  • Comparative Example 4 was prepared from the following:
  • This toner had weight ratios (solids/solids) of:
  • Comparative Example 5 was prepared from the following:
  • Organosol pigment 4 : 1 charge director: organosol 0.125:1
  • Comparative Example 6 Comparative Example 6 was prepared from the following:
  • Example 7 was prepared from the following:
  • This toner was used as a starter and a replenisher for imaging on a 3M Digital MatchprintTM Proofer.
  • the starter developer concentration was adjusted to 0.4% solids and the replenisher concentration was at 12% solids.
  • the starter developer was cycled to produce 100 images while replenishing at a rate of 1.2 grams/image.
  • the quality ofthe image obtained from the first cycle was comparable to the quality ofthe image ofthe last cycle.
  • the cycled developer maintained its charge per transmission optical density and conductivity throughout 100 cycles.
  • Example 8 was prepared from the following:
  • This toner had weight ratios (solids/solids) of:
  • Example 9 was prepared from the following:
  • This toner had weight ratios (solids/solids) of:
  • Example 10 was prepared from the following:
  • This toner had weight ratios (solids/solids) of:
  • the Liquid toners prepared above were tested using a Keithley Digital Electrometer Model 616 and a TREK Power Supply Model 601 A-2 hooked to parallel conductive plates (PCP).
  • the liquid toner was poured into a beaker containing the PCP so that toner is between the PCP.
  • One ofthe conductive plates was transparent and attached to the negative electrode, the other was attached to the positive electrode.
  • the toner was allowed to deposit for one second under about 1000 V/0.2 cm onto the transparent plate.
  • the plate was dried and the transmission optical density was measured using a Gretag 182 Transmission Densitometer. The charge was determined from the integrated i (current) vs t (time) curve.
  • the conductivity was determined from the extrapolated current at 0 seconds time.
  • the toners having the inventive charge directors show higher transmission optical density than do toners having commercial charge directors. Images formed with toners having the inventive charge director also were substantially free of tailing artifacts and had high resolution of fine details.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Liquid Developers In Electrophotography (AREA)
  • Developing Agents For Electrophotography (AREA)

Abstract

La présente invention a pour objet un orientateur de charge de type nouveau, consistant en un complexe visqueux à poids moléculaire élevé composé d'un savon d'aluminium et d'un savon de zirconium. Ledit complexe associe étroitement des particules de toners et présente une migration très faible dans le liquide porteur de toners.
PCT/US1996/008372 1995-07-21 1996-06-03 Toners liquides a orientateur de charge complexe de zirconium et d'aluminium Ceased WO1997004363A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US50537995A 1995-07-21 1995-07-21
US08/505,379 1995-07-21

Publications (1)

Publication Number Publication Date
WO1997004363A1 true WO1997004363A1 (fr) 1997-02-06

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005040935A1 (fr) * 2003-10-26 2005-05-06 Hewlett-Packard Development Company, L.P. Procede de production de developpateur liquide

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US498860A (en) * 1893-06-06 Column
US5306590A (en) * 1991-12-23 1994-04-26 Xerox Corporation High solids liquid developer containing carboxyl terminated polyester toner resin
US5364726A (en) * 1990-03-30 1994-11-15 Xerox Corporation Liquid developers having curable liquid vehicles
US5378574A (en) * 1988-08-17 1995-01-03 Xerox Corporation Inks and liquid developers containing colored silica particles

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US498860A (en) * 1893-06-06 Column
US5378574A (en) * 1988-08-17 1995-01-03 Xerox Corporation Inks and liquid developers containing colored silica particles
US5364726A (en) * 1990-03-30 1994-11-15 Xerox Corporation Liquid developers having curable liquid vehicles
US5306590A (en) * 1991-12-23 1994-04-26 Xerox Corporation High solids liquid developer containing carboxyl terminated polyester toner resin

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005040935A1 (fr) * 2003-10-26 2005-05-06 Hewlett-Packard Development Company, L.P. Procede de production de developpateur liquide

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