US3788203A

US3788203A - Justification apparatus

Info

Publication number: US3788203A
Application number: US00301381A
Authority: US
Inventors: W Rhodes
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1972-10-27
Filing date: 1972-10-27
Publication date: 1974-01-29
Anticipated expiration: 1991-01-29

Abstract

A method for justifying a line of type from existing typographic material and a character generator is disclosed. An electrostatic charge pattern corresponding to at least a part of the image to be printed is formed. The image is developed and justification calculated. During the transferring process, the image-bearing member is selectively disengaged and re-engaged with the transfer member according to predetermined values to obtain the effect of justifying the line. This process is applicable to generally any form of imaging involving a transferable image or character.

Description

United States Patent 1191 Rhodes 1 Jan. 29, 1974 JUSTIFICATION APPARATUS [75] Inventor: Warren L. Rhodes, Rochester, NY.

[73] Assignee: Xerox Corporation, Stamford,

Conn.

[22 Filed: Oct. 27, 1972 21 Appl. No.: 301,381

Related U.S. Application Data [62] Division of Ser. No. 115,299, Feb. 16, 1971.

[52] U.S. Cl 95/45, 355/3, 355/17 [51] Int. Cl B4lb 23/00 [58] Field of Search 95/45; 355/3, 17

[56] References Cited UNITED STATES PATENTS 2,207,266 7/1940 Ogden 95/45 .1

Primary Examiner-John M. Horan Attorney, Agent, or FirmJames J. Ralabate et al.

[ ABSTRACT A method for justifying a line of type from existing typographic material and a character generator is disclosed. An electrostatic charge pattern corresponding to at least a part of the image to be printed is formed. The image is developed and justification calculated. During the transferring process, the image-bearing member is selectively disengaged and re-engaged with the transfer member according to predetermined values to obtain the effect of justifying the line. This process is applicable to generally any form of imaging involving a transferable image or character.

6 Claims, 2 Drawing Figures PMENTED 3 788 203 SHEET 1 0F 2 FIG. I

PATENTED 3, 788,203

SHEET 2 [1F 2 FIG. 2

JUSTIFICATION APPARATUS This is a division, of application Ser. No. 115,299, filed Feb. 16, 1971.

BACKGROUND OF THE INVENTION This invention relates to the printing arts and more specifically to a technique for justifying the text of reproducible copy.

In modern photographic typesetting an entire line of type must be keyboarded before any character images are produced. The justification must be calculated and the characters recorded one by one, moving the photosensitive receiver to the correct position for each character. In this mode of operation errors cannot be detected until the justification has been completed and the photosensitive member exposed and developed.

It is common practice to make all lines of type the same length. The process of making each line the same length is called justification or justifying the line. This is accomplished by adding more space between words or letters or decreasing the space to make room for another word or syllable in the line. Justification not only takes time but also in photographic typesetting or other cold type composition, justification can only be accomplished after a line has been keyboarded. Only rarely in composition does a line come exactly to full measure at the end of a word or sentence. Most likely the final word falls short of the line or it is too long for the space remaining in the line. In the former case, extra space must be placed between words and occasionally within words in the latter case space between words must be reduced or the last word must be hyphenated and continued on the following line. Proper spacing is the most important factor in the composition.

Various techniques are utilized for justifying type. Computers have been used to determine where the lines should end and put extra space between the words whenever necessary to make the right margin straight, that is, to justify the text. Although effective, this approach obviously introduces highly complex machinery in order to achieve the effect desired. Other approaches have been utilized such as second pass typesetting, i.e. keyboarding each line twice and calculating the justification after the first keyboarding, however, this approach is not without its disadvantages. For example, the two passes require extra time and errors which occur in the second pass cannot be detected before the final hard copy is made.

It is, therefore, an object of this invention to provide a method for justifying type which will overcome the above-noted disadvantages.

Still a further object of this invention is to provide a simple straightforward technique for justifying type.

Yet, still a further object of this invention is to provide a method for justification utilizing electrophotographic concepts.

Another obect of this invention is to provide a novel justifying xerographic typesetter.

The foregoing objects and others are accomplished in accordance with the present invention, generally speaking, by providing a method of producing a transferable image representing the character or groups of characters (line print) to be printed. For example, an electrostatic charge pattern corresponding to line copy to be reproduced is formed on the surface of a support member. The electrostatic latent image of the copy to be reproduced is made visible by dusting the image areas with toner particles. The words in the line are formed in this manner and justification calculated. The toner particles representing the various images formed are transferred to the surface of a copy sheet. Justification of each line is realized based upon the precalculated values, by separating, when necessary, the image support member from the transfer sheet and moving one with respect to the other the desired amount to produce the effect ofjustifying the line. The space may be adjusted between letters in the words or between the words themselves.

The invention is further illustrated in the accompanying drawings wherein:

FIG. 1 represents a side view of a xerographic apparatus capable of justifying lines which have already been formed but not justified; and

FIG. 2 represents an isometric view of a xerographic character generator with image display capability.

Referring now to FIG. 1 there is seen a justifying xerographic typesetter in the form of a cylindrical drum identified as 1 comprising a conductive support substrate 2 and a photoconductive insulating layer 3. The drum, when in operation, is generally rotated at a uniform velocity in the direction indicated by the arrow so portions of the drum periphery pass the charging unit 18 and having been uniformly charged passes beneath a scanning mechanism 19 or other means for exposing the charged plate to the image to be reproduced. Subsequent to charging and exposure sections of the drum surface move past the developing unit generally designated 21. The developing unit represented in the present illustration is of the cascade type which includes the powder container or cover 22 with a trough at the bottom containing a supply of developing material 23. The developer is picked up from the bottom of the container and dumped or cascaded over the drum surface by a number of buckets 24 on an endless belt 26. This development technique is more fully described in U. S. Pat. Nos. 2,618,551 and 2,618,552 and utilizes a two component development mixture including finelydivided electroscopic marking particles or toner and larger carrier beads. The carrier beads serve both to deagglomerate the fine toner particles for easier feeding and charge them by virtue of the relative position of the toner and carrier material in the triboelectric series. The carrier beads and toner particles are cascaded over the surface of the drum. The electrostatic field of the charge pattern of the drum attracts toner particles from the carrier beads, thereby developing the image. The carrier beads along with any toner particles not used to devleop the image fall back into the bottom of container 22. The developed image continues around until it reaches the transfer station generally designated Charging unit 18 consisting of a voltage source 31 and a corona discharge device 33 is selected so as to provide an electrical discharge to the surface of the drum under almost any conditions of relative humidity and atmospheric pressure normally encountered.

Any suitable photoconductive material may be used in the course of this invention. Typical inorganic photoconductive materials include sulfur, selenium, zinc sultide, zinc oxides, zinc cadjium sulfide, cadmium sulphoselenide and cadmium sulfide. Typical organic photoconductors include sensitized polyvinylcarbazole,

phthalocyanine, triphenylamine and similar materials. In addition, a photoconductive binder insulating layer may be used such as disclosed in U.S. Pat. Nos. 3,121 ,006 and 3,121,007. The specific binder material chosen will depend upon the nature of the photoconductive pigment utilized to prepare the electrophotographic plate of the present invention. Of course, where suitable, mixtures of the above-mentioned materials may be utilized.

Any suitable backing material for the xerographic plate may be used in the course of the present invention. Generally, the preferred backing material will have an electrical resistance less than that of the photoconductive layer so that it will act as a ground when the electrostatically-charged coating is exposed to light. Typical materials include aluminum, brass, steel, copper and both conductive and non-conductive paper. Other materials having an electrical resistance similar to the aforementioned can also be used to receive the photoconductive layer. Other non-conductive materials such as thermoplastics may be used. However, when they are employed, it is necessary to charge both sides of the xerographic plate according to the process set forth in U. S. Pat. No. 2,992,883.

Any suitable toner or developer may be used in the course of the invention such as is disclosed in U. S. Pat. Nos. 2,788,288 and 3,079,342 and RE No. 25,136. The toner is generally a resinous material such as styrene, phenolformaldehyde resins and other similar materials. The developer powder or electroscopic marking particles may be applied directly to the latent image of the xerographic plate or admixed with the carrier such as glass beads, as discussed with respect to the illustration. A developer particle is chosen so that it will be attracted electrostatically to the charged image and/or repelled from the background area to the charged image and held thereon by electrostatic attraction. If a negative charge is applied to the photoconductive insulating material, a positive toner is used which adheres to the negatively charged image. If the charge applied is such that the latent image retains a positive charge, then a negative toner will be utilized. Liquid developers may also be used in the course of the present invention such as disclosed in U. S. Pat. No. 2,890,174 and 2,899,335. Generally, the liquid developer comprises a combination of mutually compatible ingredients which, when brought in contact with an electrostatic latent image will deposit the pigment portion on the surface of the image in an imagewise configuration. In its sim' plest form, the composition comprises a finely-divided powder, a high resistance liquid and an ingredient to prevent agglomeration.

Any suitable development means may be used such as the cascade development as herein illustrated, powder cloud development, more fully described in U. S. Pat. Nos. 2,725,305 and 2,981,910 and magnetic brush development, more fully described in U. S. Pat. Nos. 2,791,949 and 3,0l5,305.

Referring again to FIG. 1, a sheet feed mechanism 51 supplies copy paper 52 by way of rollers 53 to the surface of the photoconductive drum between a conductive transfer roller 54 which is connected to ground by way of a power source 61. The copy sheets are fed one at a time into the transfer station 27 and held to the transfer roller 54 by fastening means 55. As each justitied line is transferred to the copy sheet the transfer roller is moved laterally to prepare the copy sheet for subsequent transfers. The transfer roller makes the necessary revolutions to allow for reproduction of an entire page of topographic information. The copy sheet is then released from fastener 55 and delivered to the fixing station, herein represented as a heat fusing mechanism 56, from whence it is discharged into storage bin 57. The potential applied to the transfer roller is opposite in polarity to the charged toner particles so as to effect electrostatic transfer of the toner particles to the copy or transfer sheet. A drive mechanism 62 is made available for disengaging the transfer roller 54 along with the transfer sheet 52 from the surface of the photoconductive member 1. Thus, in order to attain the desired justification of the line being copied, the change in spacing between words or, if desired, letters may be accomplished by separating the xerographic plate from the transfer sheet and moving one with respect to the other the prescribed distance. A very simple and non-.

by the transfer roller and continued image transfer reinitiated. Te entire process is an instantaneous one and, therefore, need not delay the overall speed of the system.

Any suitable means may be used to transfer the developed image from the surface of the photoconductive plate to the transfer sheet or substrate. Thepreferred approach comprises the electrostatic transfer technique represented by the instant illustration. However, other techniques may be utilized such as adhesive transfer and pressure transfer.

Any suitable material may be used as the transfer substrate for the developed image such as polyethylene terephthalate, ordinary bond paper, polyvinylfluoride, polyethylene and polypropylene. The toner image may be fixed to the surface of the transfer substrate by any suitable technique such as solvent and vapor fusing or heat fusing as in the present illustration.

After passing the transfer station, the xerographic drum will continue around beneath cleaning brush 38 which prepares the surface of the plate for recycling. Although the invention has been described in connection with corona charging, it is to be understood that this is exemplary only and that the self-regulating plate may, in fact, be employed with any suitable charging technique. Other suitable charging techniques include friction charging and induction charging as described in U. S. Pat. Nos. 2,934,649 and 2,833,930 respectively, and roller charging as described in U. S. Pat. No. 2,934,650.

Although for the purposes of the present discussion the electrostatic charge pattern is represented as being formed on a photoconductive insulating surface through the steps of charging the surface and selectively dissipating the charge by exposure to a pattern of electromagnetic radiation, other methods suitable for forming electrostatic charge patterns may be used. For example, selective deposition of an electrostatic charge may be achieved by impressing a charge through an image stencil onto an insulating surface, imposing a potential on a shaped conductor or electrode, cathode ray tube image presentation of computer generated information to a uniformly charged photoconductive surface or the like. Thus, the image may be formed utilizing photosensitive materials, as herein illustrated, or by any suitable technique such as set forth above.

Referring now to FIG. 2 there is seen a xerographic character generator comprising a continuous flexible image support substrate 70, herein represented as a flexible photoconductive belt configuration, driven by

rollers

71, 72, 73 and 74. The belt, when in operation, is rotated at a uniform velocity in the direction indicated by the arrow so that portions of the belt pass the charging unit 75 and a character generating station 76 capable of projecting image characters one at a time onto the surface of the charged belt. The resulting images 77 pass though a developer station 78 containing a development system of the nature above described. Following development of the electrostatic characters produced, the belt proceeds past a viewing station 79 enabling a complete line of copy to be reviewed for error prior to transfer to the final copy or transfer sheet. If an error is detected in the image produced the belt may be stopped and reversed so as to correct the discrepancy. The belt then proceeds to the transfer station generally designated 80 comprising a contacting roller 81 and transfer sheet 82. The contacting roller is designed so as to retract and translate in phase with the belt. Thus, after having been reviewed for errors at the viewing station, the characters are transferred from the belt to the transfer sheet in a manner which allows for justification of the line copy produced by selectively disengaging and reengaging the imaged belt with the transfer sheet by way of the contact roller. The belt then proceeds to a cleaning station 83 and is prepared for recycling. Thus, the system disclosed by FIG. 2 represents a device with display capabilities capable of translating individual characters.

Although the imaging process and apparatus of the present invention have been described in conjunction with xerographic principles any suitable process capable of producing a transferable image, such as a wax image capable of splitting off a portion from its surface, xeroprinting images or ink images may be adapted and effectively used in an apparatus of the nature herein described.

It is to be understood that numerous variations and modifications may be made within the scope of the present invention. Thus, for example, the structural configuration of the machine apparatus illustated may take the form ofa flat bed press or platen and need not, necessarily, be cylindrical in shape. in addition, the system of the present invention may be combined with some of the generally known techniques for justifying copy so as to streamline and update these presentlyknown approaches. For example, in one form the device might be manual and in another it might be mechanized using a computer to calculate the required spacing and machinery to accomplish engagement and disengagement between the transfer substrate and electrophotographic support member. The copy may be transferred directly to the final receiver or transfer sheet or it may be first transferred to an intermediate substrate and then to the final copy sheet.

Other embodiments will occur to those well versed in the above-disclosed technologies. These variations and modifications are intended to be encompassed within the scope of cadmium invention.

I claim:

1. An apparatus for justifying topographic material comprising in combination means for electrostatically forming and developing a transferable image on the surface of an image support member, means for physically transferring at least a portion of said image to the surface of a receiving substrate and means for disengaging and re-engaging said image support member and said receiving substrate so as to adjust one with respect the other to effect spacing of the individual images and thereby justification of said topographic material.

2. The apparatus as disclosed in claim 1 wherein said transferable image comprises toner particles.

3. The apparatus as disclosed in claim 2 wherein said image support member comprises an electrophotographic plate.

4. The apparatus as disclosed in claim 1 further including a means for viewing said image.

5. The apparatus of claim 1 wherein the means for physically transferring the image to the surface of the receiving substrate is an electronic discharge device capable of generating an electrostatic field capable of attracting the material which forms the transferable image.

6. The apparatus of claim 1 wherein the means for physically transferring the image to the surface of the receiving substrate is a pressure roller.

UNITED sTATEs PATENT OFFICE CERTIFICATE OF CGRRECTION Patent No. ,2 3 Dated January 29, 1974 Inventor(s) r n L. Rhodes It is certified that error appearsin the above-identified patent and that said Letters Patent are hereby corrected as shown below:

1. Column 2, line 66, "cadjium" should read -cadmium.

2. Column 4, line 25, "Te" should read -The' 3. Column 6, line 18, "cadmium" should read this.

Signed and sealed this 9th day of April lQYL SEAL Attest:

EDWAIU) M.FLETCHER,JR. C MARSHALL DAN N Attesting, Officer Commissioner of Patents DRM PO-IOSO (10-69) USCOMM-DC 60376-P69 9 us. GOVERNMENT PRINTING OFFICE: I988 0-388-33L patent 3,788,203 Dated January 29, 1974 lnventor( 'Warren L. Rhodes It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

1. Column 2, line 66, "cadjium" should read cadmium--.

2. Column 4, line 25, "Te" should read -'I'hei-- 3. Column 6, line 18, "cadmium" should read -this--.

Signed and sealed this 9th day or April 197E.

(SEAL) Attest:

EDWAIH) I'LFLETCHERJR, 0. MARSHALL DANN Attesting Ofiioer Commissioner of Patents QR USCOMM-DC 60376-P69 k U.S. GOVERNMENT PRINTING OFFICE: [9'3 0-368-33,