US3460476A - Imaging process - Google Patents

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US3460476A
US3460476A US516243A US3460476DA US3460476A US 3460476 A US3460476 A US 3460476A US 516243 A US516243 A US 516243A US 3460476D A US3460476D A US 3460476DA US 3460476 A US3460476 A US 3460476A
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plate
photoconductive
lithographic
image
glass
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Jay Kirk Swigert
Richard L Lane
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Xerox Corp
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Xerox Corp
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/26—Electrographic processes using a charge pattern for the production of printing plates for non-xerographic printing processes
    • G03G13/28—Planographic printing plates
    • 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
    • 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
    • G03G5/10—Bases for charge-receiving or other layers
    • G03G5/102—Bases for charge-receiving or other layers consisting of or comprising metals

Definitions

  • This invention relates to an imaging system, and more specifically, to lithography.
  • Lithographic printing is a well known and established art. In general, the process involves printing from a flat plate, depending upon different properties of the image with the non-image areas for printability. In conventional lithography, the non-image area is hydrophilic while the image area is hydrophobic. In the lithographic printing process, a fountain solution is applied to the plate surface which wets all portions of the surface not covered by the hydrophobic image. This solution keeps the plate moist and prevents it from scumming up. An oil based printing ink is applied to the image surface depositing the lithographic ink only on the image area, the hydrophilic nonimage repelling the ink.
  • the ink image may then be transferred directly to a paper sheet or other receptive surface, but generally it is transferred to a rubber offset blanket which in turn transfers the print to the final paper sheet.
  • a lithographic plate is first dampened with an aqueous fountain solution and then inked with a lithographic ink and finally printed.
  • lithographic plates can be made in a photoconductive system by utilizing the conventional developed xerographic plate as a lithographic printing plate.
  • a zinc oxide type plate is charged by conventional means exposed to the image to be reproduced, and developed with conventional xerographic toner.
  • the toner used to develop the image is generally hydrophobic in nature as is the background, nonimaged areas of the conventional binder type xerographic plate.
  • a differential must be established between the tonered image and the background of the plate.
  • the background of the xerographic plate be treated, either by the use of a conversion solution, to make it hydrophilic in nature or by removal with a selective solvent. After the alteration of the background, the plate is then wetted with a non-aqueous or oil based ink whereby the toner will accept the ink and the now hydrophilic background will repel the ink.
  • Another object of this invention is to provide an imaging system utilizing a lithographic master prepared from a xerographic plate.
  • Still a further object of this invention is to provide an imaging system wherein the novel lithographic plate can be reused.
  • Still a further object of this invention is to provide an imaging system utilizing a lithographic master prepared by a one-step process.
  • An additional object of this invention is to provide a novel lithographic plate wherein both sides of the plate may serve as the printing surface.
  • a xerographic plate prepared by fixing to the surface of a receiving substrate a glass photoconductive insulating layer.
  • the layer can then be electrostatically charged and imaged in accordance with the conventional xerographic imaging process more fully described in US. Patent 2,297,691.
  • the plate of the present invention is generally prepared by intimately mixing a photoconductive material in a glass binder insulating composition and fixing the resulting photoconductive blend to a conductive backing to form a substantially uniform layer comprising photoconductive particles embedded in a glass binder composition.
  • the electrostatic image is developed with a hydrophobic developer and the resulting developed image fixed so as to produce a duplicating plate having both hydrophobic and hydrophilic properties.
  • the lithographic master can then be used in a one-step process to continuously make prints whereby a lithographic ink is applied to the master, the ink adhering; only to the hydrophobic tonered image and the master subsequently contacted with a copy sheet to transfer the image.
  • a lithographic ink is applied to the master, the ink adhering; only to the hydrophobic tonered image and the master subsequently contacted with a copy sheet to transfer the image.
  • the photoconductive insulating layer comprising the glass binder composition of this invention is hydrophilic in nature and therefore, already having the necessary hydrophilic properties need not be treated to establish a differential between the non-image and image areas of the lithographic master, a procedure which is known to be required by the conventional lithographic plates as taught in US. Patents 3,107,169 and 3,001,872.
  • FIG. 1 represents a magnified cross section through a lithographic printing plate having a two-phase photoconductive insulating layer
  • FIG. 2 represents a magnified cross-section through a lithographic printing plate having a homogeneous, single phase photoconductive insulating layer.
  • FIG. 2 illustrates a lithographic plate 7 wherein the photoconductive insulating layer 9 is a homogeneous, single-phase glass composition.
  • The. substrate 8 and developed image 10 are similar to the substrate 2 and image 6 of FIG. 1.
  • a glass binder insulating composition is blended with a photoconductive material in proportions of from about to about 45 parts of the photoconductive material to about 100 parts of a glass binder composition.
  • a photoconductive material in proportions of from about to about 45 parts of the photoconductive material to about 100 parts of a glass binder composition.
  • the finely divided photoconductive particles and glass binder particles are desirably dispersed in a liquid, such as distilled Water, or an organic liquid, such as ethylene glycol, by any suitable means, such as in a ball mill.
  • the photoconductive material and the glass binder composition may be ground together in water using small amounts of sodium silicate, sodium hydroxide, and boric acid as dispersing agents.
  • the resulting slurry is thoroughly dried to remove most of the solvent and then blended with an Organic liquid such as isopropyl alcohol.
  • the milling step is repeated to produce the final photoconductive coating composition.
  • the iesulting composition is then applied to the desired surface by flow coating, dipping, spraying, electrostatically, with a doctor blade or by any other sutiable coating operation. Care must be taken that air bubbles or other discontinuities are eliminated from the slurry before coating to insure good adhesion to the underlying substrate and to retain good photoconductive properties.
  • the coating is dried to remove most of the liquid and the plate subsequently fired at the necessary temperature to fuse and bond the glass binder composition to the base substrate and produce a uniform layer of the photoconductive pigment dispersed in the glass binder composition.
  • the firing temperature is such that it is suflicient to fuse the glass binder composition and, therefore, will vary with the particular binder composition chosen.
  • An applicable temperature range is found to be about 300 to 1500 F. again, depending upon the gass binder composition.
  • the glass binder composition material should be so selected relative to the photoconductive material so that the melting point of the binder is lower than that of the photoconductive material and also the base material. Thus, the maximum melting temperature permissible in the binder will vary depending upon the photoconductive material selected.
  • the length of time necessary to fire the glass binder photoconductive composition in order to fuse and bond it to the underlying substrate will be dictated by the glass frit formulation chosen. Preferred firing time ranges from about 1 to 60 minutes depending upon the materials used, in order to obtain optimum electrical characteristics.
  • the support layer should be cleaned prior to coating thereon. Any suitable cleaning technique may be used, such as the application of organic solvents. Aluminum layers, for example, may simply be heated to firing temperature and cooled before the coating material is applied.
  • the resulting glass binder photoconductive plate is electrostatically charged in the dark and the charged surface selectively exposed to a light source to produce a latent image.
  • the imaged surface is next developed with hydrophobic electroscopic particles or toner, the developer adhering to the areas corresponding to the latent image, and the resulting tonered image fused by heating the plate to a temperature of about 200500 F. for about 2-12 minutes. It is also possible to develop the electrostatically charged image with a liquid developer containing charged hydrophobic particles suspended in a carrier.
  • the photoconductive plate is then fastened to a press cylinder of a lithographic press.
  • the printing operation is carried out utilizing commercially available fountain solutions and lithographic inks.
  • the tonered particles used to develop the electrostatic latent image may consist of a pigmented resin which is hydrophobic in nature and which may be readily wetted by a lithographic ink.
  • the printing surface of the glass binder photoconductive plate of this invention is such that, when dry, it will readily accept a water-repellant image which adheres tenaciously thereto and shall neither be pulled away by printing ink nor washed away by the wet-out or fountain solutions. Furthermore, the non-image areas of the plate are readily wetted by the fountain solutions and hold a film thereof on the surface of the non-image areas and do not permit the aqueous film to be displaced therefrom by the lithographic printing ink.
  • the plate is cleaned by removing the tonered image with a selective solvent, such as methyl ethyl ketone, or acetone.
  • a selective solvent such as methyl ethyl ketone, or acetone.
  • the commercially available acidic fountain solutions utilized in the course of this invention are neutralized with a basic material, such as sodium hydroxide, to increase the pH of the solution and to reduce etching.
  • the glass binder photoconductive plate can be refired at a temperature and for a time suflicient to regenerate the plate. Regeneration of the plate is generally accomplished at a temperature of about 200l100 F. for a time of about 1-10 minutes, depending upon the materials used.
  • any suitable glass binder composition which displays wettable hydrophilic properties may be used in the course of the instant invention.
  • Typical such glass binder compositions are borosilicates, alkali silicates, lead silicates, lead alumino phosphates, soda-lime silicates and Pyroceram Glass No. and No. 89, glass formulations available from the Corning Glass Company.
  • Other usable glass binder materials are disclosed in U.S. Patent 3,151,982. Preferred are those glass frits which have a fusing temperature at the lower end of the acceptable temperature range. These glass binder materials have been found to possess substantial amounts of boric oxide and lead oxide.
  • Sodium and potassium oxide also lower the fusing point of the glass frit, but must be limited to prevent water solubility. Fluorides also lower melting temperature but cause silica and boric oxide solubility. Calcium oxide, and especially zinc oxide and cadmium oxide lower the melting point to a certain degree. Antimony and arsenic oxides also lower the melting point of the glass binder material.
  • the photoconductive material should be in a suitable, finely divided state. While photoconductive particle sizes as large as about 50 microns may be used, it is preferred that particle size be as small as possible in order to obtain optimum results. In general, particle sizes of no more than about 20 microns are used, preferably the photoconductive particles should have an average particle size of no more than about one micron.
  • any suitable photoconductive material may be used in the course of this invention.
  • Typical such inorganic photoconductive materials are sulfur, selenium (vitreous, amorphous, monoclinic) zinc sulfide, zinc oxide, zinc cadmium oxide, zinc magnesium oxide, cadmium selenide, zinc silicate, calcium-strontium sulfide, cadmium sulfide, mercuric iodide, mercuric oxide, mercuric sulfide, indium trisulfide, gallium triselenide, arsenic disulfide, arsenic trisulfide, arsenic triselenide, antimony trisulfide, cadmium sulfoselenide, doped chalcogenides of Zinc and cadmium, aluminum oxide, bismuth oxide, molybdenum oxide, lead oxide, molybdenum iodide, molybdenum selenide, molybdenum
  • preferred materials in order to obtain optimum results are appropriately doped chalcogenides of zinc and cadmium, more specifically, the sulfides and selenides of these metals either as mixed sulfides and selenides of zinc and/or cadmium or as a mixed zinc and cadmium sulfide or selenides, simple compounds of zinc and cadmium sulfide, cadmium sulfoselenide, and mixtures thereof.
  • Any suitable organic photoconductive material which is capable of withstanding the temperature requirements of the present invention may be used in the course of this invention. Typical such materials are the phthalocyanine pigments.
  • the thickness of the photoconductive insulating layers of the instant invention may vary from about 5 microns to about 200 microns. It is preferred that the layers be from about 10 to about 150 microns thick in order to achieve optimum results.
  • the photoconductive insulating layers of the present invention are characterized by outstanding wear-resistance properties. The desired thickness may be built up by multiple coatings, if necessary.
  • any suitable material may be used as the substrate for the lithographic master of this invention.
  • the base or substrate used in preparing lithographic binder plates according to this invention provides physical support for the photoconductive insulating layer and also should have an electrical resistance less than the photoconductive layer so that it will act as a ground when the electrostatically charged coating is exposed to light.
  • Typical such materials are metal surfaces such as aluminum, brass, steel, e.g. stainless and low carbon, copper, nickel, zinc, alloys and mixtures thereof.
  • Other materials having electrical resistances similar to the aforementioned can also be used as the backing material to receive the photoconductive layer thereon.
  • the material must, however, be capable of withstanding the temperature requirements for fusing the glass binder plate and have a coefficient of thermal expansion compatible with the particular glass binder composition used.
  • the base substrate may be coated on both sides with the glass binder photoconductive compositions of the present invention.
  • the glass binder photoconductive compositions of the present invention When this practice is followed, it then becomes possible to image on either sides of the coated plate thus providing a printing plate with lithographic properties both sides of which may serve as the printing surfaces.
  • Any suitable wet-out or fountain solution may be used in the course of this invention.
  • Typical such fountain solutions are 1% solutions by volume of gum cellulose and water, gum arabic and water, glycerol and water and isopropyl alcohol and water. Distilled water may also be used as the wet-out solution.
  • Other suitable fountain solutions are disclosed in US. Patent 3,107,169.
  • the fountain solutions may contain other constituents, such as for example, formaldehyde, and if glycerin is not present, it
  • the fountain solutions containingthe glycerin or formaldehyde additive or mixtures thereof are preferred inasmuch as the resultant lithographic plate can be kept before use for relatively long periods of time as compared to those plates treated with a fountain solution not containing the respective additive.
  • Solutions containing gum arabic are also found to be very effective inasmuch as a lithographic plate treated with such a solution is found to retain its hydrophilic properties in the non-image areas for relatively long periods of time, after removal from the press, so that the resultant printing plate can be reused without subjecting them to an additional treatment with the fountain solution.
  • the toner is generally a resinous material which when fixed has hydrophobic properties and will attract oily inks.
  • Typical such developer powders are styrene polymers, polymers of substituted styrenes, for example, Piccolastics, commercially available from the Pennsylvania Industrial Chemical Corporation, phenol formaldehyde resins as well as other resins having hydrophobic properties.
  • Other inorganic developer powders that may be found suitable for use in the present invention are powdered zinc, powdered copper, and sulfur, among others.
  • the developer powder may be applied directly to the latent image or admixed with a carrier such as glass beads.
  • the toner is applied in the form of a mixture with magnetic particles such as magnetic iron to impart a charge to the developer powder particles triboelectrically.
  • a developer powder is so chosen that it is attracted electrostatically to the charged image 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 applied 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 applied.
  • liquid developers may also be used in the course of this invention.
  • Such developers are disclosed in US. Patents 2,890,174 and 2,899,335.
  • the developer comprises a liquid combination of mutually compatible ingredients, which when brought into contact with an electrostatic latent image, will deposit upon the surface of the image in an image-wise configuration.
  • the composition comprises a finely divided opaque powder, a high resistance liquid and an ingredient to prevent agglomeration.
  • Liquids which have been found suitable include such organic high resistance liquids as carbon tetrachloride, kerosene, benzene, tetrachloroethylene and any substituted hydrocarbon having a boiling point between about 70 and 200 C.
  • any of the finely divided opaque solid materials known in the art such as carbon black, talcum powder, or other pigments may be used in the liquid developer.
  • Silica aerogel commercially available from Monsanto Chemical Company is the deagglomeration ingredient generally used.
  • any conventional and/ or suitable ingredient known to be useful by the prior art in a liquid development system may be utilized.
  • any suitable lithographic ink may be used in the course of this invention.
  • Typical such lithographic inks and their properties are disclosed in Printing Ink Tech nology by E. A. Apps, Chapter 11.
  • the inks are of the same fundamental style as good quality letter-press inks, and the simplest type consist of a pigment mixture dispersed in a lithographic varnish, a heat-bodied linseed oil.
  • the lithographic or oil-based ink being oleophilic in nature adheres to the hydrophobic tonered image, and is repelled by the hydrophilic non-imaged areas.
  • a glass frit of the formulation above is blended with about 32 g. of a cadmium sulfoselenide photoconductive material in about 200 g. of water.
  • the resulting composition is mixed in a ball mill for approximately 18 hours.
  • the resulting blend is then thoroughly dried.
  • Approximately 200 ml. of isopropyl alcohol is added to the dried composition and the milling process is repeated for approximately 2 hours.
  • the resulting glass binderphotoconductive composition is then applied by a process of flow coating to the surface of a stainless steel sheet, approximately 75 microns in thickness.
  • the coated sheet is then dried and fired to a temperature of about 1150 F. for approximately 10 minutes.
  • the late is then charged to about 550-650 volts by means of a laboratory corotron unit powered by a high voltage power supply.
  • the charging current is 0.1 of a milliamp at 7500 volts.
  • a transparent positive USAF test chart is placed on the charged plate and exposed with a 75 watt photofiood lamp. An exposure of about 20 foot-candle seconds is required for the glass binder-photoconductive plate.
  • the electrostatic latent image produced is then developed by the cascade method of developing with a positive charged hydrophobic developer material.
  • the toner image is then fused by heating the plate to a temperature of about 400450 F. for about 6-12 minutes. Following cooling of the plate, it is wrapped on the cylinder of a lithographic printing press and operated in the conventional manner using a fountain solution composed of:
  • a lithographic ink is then applied to the printing surface of the plate and by use of a rubber off-set blanket, runs as long as about 50,000 prints are obtained.
  • Example II The process of Example I is repeated excepting zinc oxide is substituted for the cadmium sulfoselenide photoconductive material.
  • the fountain solution utilized in this instance was composed of:
  • Example III The procedure of Example I is repeated excepting cadmium sulfide is substituted for the cadmium sulfoselenide photoconductive material. In this instance, runs as long as about 50,000 prints are obtained.
  • Example IV Example V The procedure of Example IV is repeated excepting zinc sulfide is substituted for the cadmium sulfoselenide photoconductive material. Formaldehyde is substituted for the carboxymethyl cellulose of the fountain solution. Runs as long as about 53,000 prints are obtained.
  • Example VI The process of Example V is repeated excepting copper phthalocyanine is substituted for the zinc sulfide photoconductive material. Runs as long as about 53,000 prints or a plate equivalent to that of Example V is obtained.
  • Example VII A glass frit, Coming 1970, an electroluminescent phosphor imbedding glass, available from the Corning Glass Co. is utilized as the binder in this test run.
  • Example VIII The process of Example VII is repeated excepting zinc oxide is substituted for the cadmium sulfoselenide photoconductive material. Also, formaldehyde is substituted for the carboxymethyl cellulose of the fountain solution. Runs of about 50,000 prints are obtained.
  • Example IX The procedure of Example VII is repeated excepting zinc sulfoselenide is substituted for the cadmium sulfoselenide photoconductive material. Runs of about 49,000 prints are obtained.
  • Example X The process of Example I is repeated excepting Corning No. 1971 electroluminescent phosphor i-mbedding glass, commercially available from the Corning Glass Company, is substituted for the glass frit of Example I. The remainder of the procedure being the same runs as long as about 45,000 prints are obtained.
  • Example XI The process of Example X is repeated excepting zinc oxide is substituted for the cadmium sulfoselenide photoconductive material. Runs of about 50,000 prints are obtained.
  • Example XII The procedure of Example X is repeated excepting zinc sulfoselenide is substituted for the cadmium sulfoselenide photoconductive material. In this instance, formaldehyde was substituted for the carboxymethyl cellulose of the fountain solution. The lithographic plate in this instance produces successful runs as long as about 52,000 prints.
  • Example XIII The process of Example X is repeated, however, in this instance zinc sulfide is substituted for the cadmium sulfoselenide photoconductive material.
  • the lithographic plate in this case produced runs as long as about 50,000 prints.
  • Example XIV The glass frit fromulation utilized in this test run is Du Pont L232, a procelain enamel frit, commercially available from the Du Pont Co. The remainder of the procedure was similar to that of Example 1. Runs as long as about 48,000 prints are obtained.
  • Example XV A glass frit formulation corresponding to Harshaw Flux AG 850, commercially available from the Harshaw Chemical Co., is used in the lithographic plate of this example. The remainder of the procedure is similar to that of Example I. After the application of a lithographic ink, runs of about 50,000 prints are obtained.
  • Example XVI Utilizing a glass frit formulation of Example XV, a lithographic printing plate is prepared according to the procedure of ExampleI. In this instance, however, a Z1110 oxide photoconductive material is substituted for the cadmium .sulfoselenide. In this instance runs of about 50,000 prints are obtained.
  • Example XVII The procedure of Example XV is repeated excepting zinc sulfoselenide is substituted for the cadmium sulfoselenide photoconductive material. In this instance, however, formaldehyde is substituted for the carboxymethyl cellulose of the fountain solution.
  • the lithographic plate of this example produces runs up to about 53,000 prints.
  • Example XVIII The procedure of Example XV is repeated excepting zinc selenide is substituted for the cadmium sulfoselenide photoconductive material. In this instance, formaldehyde is substituted for the carboxymethyl cellulose of the fountain solution. The lithographic plate of this example produces runs up to about 53,000 prints.
  • Example XIX A glass frit formulation corresponding to Harshaw Flux AG 862, commercially available from the Harshaw Chemical Co., is used in the lithographic plate of this example. The remainder of the procedure is similar to that of Example I. After the application of a lithographic ink runs approximating 50,000 prints are obtained.
  • Example XX The procedure of Example XIX is repeated excepting zinc oxide is substituted for the cadmium sulfoselenide photoconductive material. The resulting lithographic plate produced up to about 50,000 prints.
  • Example XXI The procedure of Example XIX is repeated excepting zinc cadmium sulfide is substituted for the cadmium sulfoselenide photoconductive material. Runs up to about 50,000 prints are obtained.
  • Example XXII The procedure of Example XIX is repeated excepting zinc cadmium selenide is substituted for the cadmium sulfoselenide photoconductive material. The lithographic plate obtained is comparable to that of Example XIX.
  • Example XXIII A lithographic plate is prepared according to the procedure of Example I. After the plate is used to make the prints desired, the imaged areas of the plate are cleaned with methyl ethyl ketone in order to remove the developed image. The lithographic plate is then regenerated by heating to about 450 F. for approximately two minutes. The plate is recharged and reimaged according to the procedure of Example I with the resulting lithographic plate producing up to 45,000 prints.
  • Example XXIV In order to further demonstrate the reusability of the lithographic plates of this invention the printing plate of Example IV was treated in a manner similar to that of Example XXIII. It was found as in the preceding example that the rejuvenated lithographic plate could be reimaged and reused in lithography, the resulting plate producing up to about 48,000 prints.
  • any of the above listed typical materials ' may be substituted when suitable in the above examples with similar results.
  • steps used to prepare the lithographic plate of the present invention other steps or modifications may be used, if desirable.
  • the fountain solution and lithographic ink may be applied in a single step to the surface of the plate.
  • other materials may be incorporated in the developer, ink, fountain solution photoconductive material or xerographic plate which will enhance, synergize or otherwise desirably affect the properties of these materials for the present use.
  • the spectral sensitivity of the plates prepared in accordance with the present invention may be modified by incorporating photosensitizing dyes therein.
  • a method of making multiple copies from a lithographic master which comprises forming an electrostatic latent image on the surface of a hydrophilic glass ph0t0 conductive plate, said plate comprising a conductive receiving substrate having fixed to at least one surface thereof a glass photoconductive insulating layer, developing said image with a hydrophobic developer so as to form image areas that are hydrophobic and non-image areas that are hydrophilic, applying to the imaged surface of said hydrophilic glass photoconductive plate a lithographic ink, said ink being distributed thereon conforming to said hydrophobic image in an image'wise configuration, contacting said inked surface with a transfer sheet to thereby affect the transfer of copies of said image to said sheet and repeating the inking and contacting steps until the desired number of copies are produced.
  • said glass photoconductive insulating layer comprises a photoconductive material dispersed in a glass binder insulating composition.
  • a method of making multiple copies from a xerographic image which comprises:
  • said photoconductive material comprises an inorganic photoconductive material.
  • said inorganic photoconductive material is selected from at least one member of the group consisting of zinc oxide, zinc sulfide, zinc cadmium sulfide, cadmium selenide, cadmium sulfide, cadmium sulfoselenide, zinc cadmium selenide and zinc sulfoselenide.
  • said photoconductive material comprises a phthalocyanine pigment.
  • a method of making multiple copies from a lithographic master which comprises forming an electrostatic latent image on the surface of a hydrophilic glass photoconductive plate, said plate comprising a conductive receiving substrate having fixed to at least one surface thereof a glass photoconductive insulating layer comprising an inorganic photoconductive material selected from at least one member of the group consisting of zinc oxide, zinc sulfide, zinc cadmium-sulfide, cadmium selenide, cadmium sulfide, cadmium sulfoselenide, zinc cadmium selenide and zinc sulfoselenide dispersed in a glass binder insulating composition, developing said image with a hydrophobic developer so as to form image areas which are hydrophobic in nature and non-image areas hydrophilic in nature, applying to the surface of said hydrophilic glass photoconductive plate a lithographic ink, said ink being distributed thereon conforming to said hydrophobic image in an imagewise configuration, contacting said inked surface with
  • said receiving substrate comprises a metallic material having an electrical resistance less than the photoconductive layer.

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Cited By (8)

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US3759179A (en) * 1971-05-05 1973-09-18 P Guido Credit card and signature verification system
US3837906A (en) * 1967-04-03 1974-09-24 Xerox Corp Method of making a xerographic binder layer, and layer so prepared
US3876424A (en) * 1968-02-26 1975-04-08 Canon Kk Electrophotographic liquid developing process employing non-polymer binding materials in the photoconductive
US3898083A (en) * 1973-01-05 1975-08-05 Xerox Corp High sensitivity visible infrared photoconductor
US4053863A (en) * 1971-06-03 1977-10-11 Varian Associates, Inc. Electrophotographic photoconductive plate and the method of making same
US4204865A (en) * 1975-11-17 1980-05-27 Coulter Systems Corporation Direct-imaging flexible offset printing plate and method of manufacture
US4265987A (en) * 1976-01-20 1981-05-05 Coulter Systems Corporation Lithographic printing plate and method for the preparation of same
US4705696A (en) * 1984-09-27 1987-11-10 Olin Hunt Specialty Products Inc. Method of making a lithographic printing plate, printing plates made by the method, and the use of such printing plates to make lithographic prints

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MX153652A (es) * 1979-03-22 1986-12-16 Minnesota Mining & Mfg Una estructura electrofotografica para placas de impresion

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US1803519A (en) * 1929-01-05 1931-05-05 Zeh Inc Lithographer's glass
FR1258844A (fr) * 1960-02-05 1961-04-21 Gevaert Photo Prod Nv Nouveau matériel électrophotographique
US2993787A (en) * 1955-08-30 1961-07-25 Rca Corp Electrostatic printing
US3151982A (en) * 1962-04-02 1964-10-06 Xerox Corp Xerographic plate

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US1803519A (en) * 1929-01-05 1931-05-05 Zeh Inc Lithographer's glass
US2993787A (en) * 1955-08-30 1961-07-25 Rca Corp Electrostatic printing
FR1258844A (fr) * 1960-02-05 1961-04-21 Gevaert Photo Prod Nv Nouveau matériel électrophotographique
US3151982A (en) * 1962-04-02 1964-10-06 Xerox Corp Xerographic plate

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US3837906A (en) * 1967-04-03 1974-09-24 Xerox Corp Method of making a xerographic binder layer, and layer so prepared
US3876424A (en) * 1968-02-26 1975-04-08 Canon Kk Electrophotographic liquid developing process employing non-polymer binding materials in the photoconductive
US3759179A (en) * 1971-05-05 1973-09-18 P Guido Credit card and signature verification system
US4053863A (en) * 1971-06-03 1977-10-11 Varian Associates, Inc. Electrophotographic photoconductive plate and the method of making same
US3898083A (en) * 1973-01-05 1975-08-05 Xerox Corp High sensitivity visible infrared photoconductor
US4204865A (en) * 1975-11-17 1980-05-27 Coulter Systems Corporation Direct-imaging flexible offset printing plate and method of manufacture
US4265987A (en) * 1976-01-20 1981-05-05 Coulter Systems Corporation Lithographic printing plate and method for the preparation of same
US4705696A (en) * 1984-09-27 1987-11-10 Olin Hunt Specialty Products Inc. Method of making a lithographic printing plate, printing plates made by the method, and the use of such printing plates to make lithographic prints

Also Published As

Publication number Publication date
BE691755A (xx) 1967-05-29
DE1522519A1 (de) 1969-09-11
ES334943A1 (es) 1968-03-01
SE331794B (xx) 1971-01-11
CH480672A (fr) 1969-10-31
ES346128A1 (es) 1969-03-16
FR1511173A (fr) 1968-01-26
NL6618220A (xx) 1967-06-28
GB1168268A (en) 1969-10-22

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