Classifications

• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/025—Duplicating or marking methods; Sheet materials for use therein by transferring ink from the master sheet
  • B41M5/0256—Duplicating or marking methods; Sheet materials for use therein by transferring ink from the master sheet the transferable ink pattern being obtained by means of a computer driven printer, e.g. an ink jet or laser printer, or by electrographic means
• • 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
  • G03G13/01—Electrographic processes using a charge pattern for multicoloured copies
• • 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
  • G03G13/14—Transferring a pattern to a second base
• • 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
  • G03G13/22—Processes involving a combination of more than one step according to groups G03G13/02 - G03G13/20
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G17/00—Electrographic processes using patterns other than charge patterns, e.g. an electric conductivity pattern; Processes involving a migration, e.g. photoelectrophoresis, photoelectrosolography; Processes involving a selective transfer, e.g. electrophoto-adhesive processes; Apparatus essentially involving a single such process
  • G03G17/02—Electrographic processes using patterns other than charge patterns, e.g. an electric conductivity pattern; Processes involving a migration, e.g. photoelectrophoresis, photoelectrosolography; Processes involving a selective transfer, e.g. electrophoto-adhesive processes; Apparatus essentially involving a single such process with electrolytic development
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G7/00—Selection of materials for use in image-receiving members, i.e. for reversal by physical contact; Manufacture thereof
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/06—Developers the developer being electrolytic
• • 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
  • Y10S101/00—Printing
  • Y10S101/37—Printing employing electrostatic force

Definitions

• This invention relates to an integrated process for the reproduction of a light image and to materials employed therein.
• this invention is directed to a process for the production of multiple prints from a light image.
• this invention relates to a process for preparing a master copysheet of a light image which can be used to provide multiple copies thereof.
• a recently developed image reproduction process involves electrolytically developing permanent and visible images on suitable, strongly photoconductive copysheets after exposure to light images.
• This process described more fully in United States Patent No. 3,010,883, includes the electrolysis of an electrolytic developer and particularly the selective electrodeposition of a metallic or other visibly distinct coating at the exposed portions of the photosensitive surface, e.g. by electrolytic reduction.
• Strongly photoconductive copysheets suitable for use in the above method are described in United States Patent No. 3,010,884.
• various optical sensitizers have been suggested. However, many of the dye sensitizers tend to discolor the surface of the photoconductive copysheet and detract from the quality of the image produced thereon.
• strongly photoconductive copysheet as a master for the thermal preparation of a heat stable copy thereof.
• Still another object of this invention is to provide a reproduction process involving a photoconductive copysheet in which the visible appearance of the photoconductive copysheet, both prior and subsequent to electrolytic development, does not substantially affect the copies produced therefrom.
• Yet another object of this invention is to provide a process for preparing multiple copies of a light image.
• Still another object is to provide a process for the preparation of multiple copies of a radient image from a reusable photoconductive copysheet.
• thermal processes refers generally to processes requiring the use of heat.
• the process of this invention comprises exposing photoconductive, electrolytically developable copysheet to produce a differential conductivity pattern thereon, electrolytically forming a pattern of a vaporizable image forming material on the exposed surface corresponding to said differential conductivity pattern, positioning said surface of the copysheet adjacent a receptor surface, and heating said copysheet to affect the selective vapor transfer of said vaporizable image forming material to said receptor surface and the formation on said receptor surface of a visible image corresponding to said differential conductivity pattern.
• the image forming material is transferred as a vapor to a receptor (usually in sheet form) containing a color-forming coreactant, the
• vaporized image forming material and the color-forming ice coreactant interreacting on said receptor to form visibly distinct image areas.
• the vaporized image forming material is itself strongly colored, no further reactant is required on the receptor, and the receptor sheet color provides a visible contrast with the image forming material condensed thereon.
• Strongly photoconductive copysheets suitable for the practice of this invention include those described in United States Patent No. 3,010,884 and generally comprise a strongly photoconductive layer containing such materials as photoconductive zinc oxide, photoconductive indium oxide, etc., superimposed on a contiguous, electrically conductive backing or support, such as aluminum foil.
• Optical sensitizers e.g. Acridine orange, may be incorporated into the photoconductive layer to improve the spectral response. Since the color of the copysheet does not necessarily affect the quality of the thermally prepared copies, the amount of sensitizer in the photoconductive layer can be varied widely to achieve optimum results.
• the photoconductive layer may be overcoated with a Water permeable layer, such as a fihn form ing silica.
• Fihn forming silicas are generally capable of forming a stable aqueous colloidal sol with a particle size in the 1 to 100 millimicron diameter range, preferably from about 10 to about 50 millirnicrons, and their prep ration may be effected by procedures described in United States Patent No. 2,244,325. Further description of such electrolytically developable photoconductive copysheets having glossy, water permeable, cohesive and relatively transparent silica films superimposed on the photoconductive layer is given in United States Ser. No. 140,032, filed Sept. 2, 1961, now US. Patent 3,127,548.
• a differential electrical conductivity pattern is created in the photoconductive layer, corresponding to the information carried by the activating irradiation, and is utilized for selectively creating on the conductive areas by electrolytic means a pattern of vaporizable image forming material. Exposure of and electrolytic deposition on such strongly photoconductive copysheets is described in United States Patent No. 3,010,883, as mentioned earlier.
• vaporizable image forming material is defined as a material readily vaporized at temperatures above room temperature and below 300 (1., preferably between about C. and about 250 C., and which is capable of affecting a color change either by chemical reaction with other chemical compounds or, when itself strongly colored, by condensation from the vapor onto a surface Without chemical reaction. Whether the vaporizable image forming material is of the reactive or non-reactive type, therefore, it should be essentially non-vaporizing at normal room and storage conditions and can be described as normally solid under such conditions.
• the vaporiz-able image forming material may be selectively deposited on the copysheet surface by electrolysis (with or without further modification thereon) or a thin film of vaporizable image forming material may be uniformly provided on the copysheet surface and electrolytically modified in selected areas to alter its vaporizability and/ or its image forming properties.
• electrolytic deposition the former will be referred to as electrolytic deposition, and the latter will be referred to as electrolytic modification, it being understood, however, that both techniques may be employed simultaneously.
• Electrolytic deposition is accomplished by depositing the normally stable vaporizable image former directly from solution or suspension.
• the electrolytic bath contains the vaporizable image former or its electrolytic precursor in solution
• the copysheet is connected either as anode or cathode, depending on the electrical charge of the ions.
• a suitable charge bearing carrier e.g. colloidal alumina, is preferably used to effect migration toward the copysheet surface, where it is deposited.
• the vaporizable image forming deposit may consist of an interreactive volatilizable image forming compound which, upon vapor transfer from the copysheet to the receptor, reacts with a coreactant thereon to form a visible image.
• interreactive volatilizable image forming compounds include, for example, oxidizing and reducing agents, the corresponding coreactant being a compound which alters its color value upon oxidation or reduction respectively.
• One preferred class of interreactive volatilizable image forming compounds are prepared from the quaternary ring bases.
• Illustrative of the useful quaternary ring bases are l-ethyl quinolinium iodide, l-ethyl quinoldinium iodide, l-ethyl pyridinium bromide, l-ethyl- 2,6-dimethyl quinolinium iodide, l-butyl pyridinium, bromide 1-ethyl-2-methyl pyridinium bromide, 1-ethyl4- methyl pyridinium bromide, etc., which electrolytically deposited the corresponding organic reducing agent at the cathode from aqueous medium.
• Suitable materials which electrolytically deposit a volatilizable reducing agent include quinone, aromatic nitro compounds capable of reduction to amines, aromatic hydroxyl amines, etc.
• Volatilizable oxidizing agents e.g. the oxidation product of hydroquinone, catechol, tetrachlorohydroquinone, tetrahromohydroquinone, aminophenol or oxidizing agents such as N-chlorosulfonamides, etc. can also be electrolytically deposited when the copysheet is connected as anode, usually from an electrolyte containing appropriate charged particles.
• Reducible coreactants such as silver behenate, etc. contained uniformly on the receptor sheet may be reduced by a vaporized reducing agent, producing a color change on the receptor.
• the reducible coreactants on the receptor sheet may be themselves intensely colored and capable of losing or changing color intensity or value upon contact with a vaporized organic reducing agent, as illustrated by reducible dyes, such as methylene blue, crystal violet, and Malachite green.
• the vaporizable image forming deposits may contain the corresponding complexing agent, e.g. catechol (forms a complex with iron compounds), thereby forming the colored complex of the receptor sheet upon vapor transfer.
• the vaporizable image forming material when it is itself intensely colored, it may be transferred directly in vapor form to the receptor surface, where its condensation forms a visible pattern corresponding to the original image without further chemical reaction. No coreactant is thus required on the receptor sheet.
• Both water soluble and water insoluble dyestuffs may be deposited, the latter being deposited from a colloidal suspension, preferably from a suspension of positively charged particles.
• Electrolytic modification may also be used to provide a selective imagewise coating of vaporizable image forming material on the copysheet surface.
• the copysheet may be coated uniformly with a thin film of a material which is then modified by the electrolytic reaction to alter its vaporizability and/ or its image forming properties. This modification may be accomplished by selective electrolytic destruction, electrolytic masking or electrolytic immobilization of the vaporizable image forming material on the more conductive areas of the copysheet surface, as is hereinafter described.
• the mechanism of electrolytic destruction of a vaporizable image former can be accomplished by electrolytic oxidation of a vaporizable reducing agent uniformly coated on or included in the copysheet surface.
• reducing agents including pyrogallol, catechol, methyl gallate, aminonaphthols, 4mcthoxy naphthol, etc., which are anodically oxidized on the more conductive areas of the copysheet surface.
• Reducible coreactants, e.g. silver behenate, etc. contained on the receptor sheet are then reduced when contacted with the vaporized, unoxidized reducing agent, thereby producing a visible color change on the receptor surface and a visible reproduction of the original image.
• vaporizable reducing agents may also be electrolyzed cathodically in a medium that provides a relatively high pH in the light struck areas, e.g. an aqueous bath containing soluble magnesium salts.
• a medium that provides a relatively high pH in the light struck areas e.g. an aqueous bath containing soluble magnesium salts.
• the vaporizable reducing agents eg. 4-rnethoxy naphthol
• the vaporizable reducing agents are readily oxidized in the more conductive areas, thus leaving the unoxidized reducing agent only in the background areas for vapor transfer to the receptor sheet and interreaction with silver behenate or other suitable material which changes color value upon reduction.
• the mechanism of electrolytic masking involves a photoconductive copysheet containing on or immediately under its surface a uniform layer of a vaporizable image former and the selective electrolytic depositions of a mask or coating to cover or fix such image forming compound in the more conductive areas.
• the mask is usually a higher molecular weight, e.g. polymeric, material which is desirably deposited from latex and which provides a relatively impermeable barrier to vapor. Either cathodic or anodic deposition may be used, depending on the charge on the latex particles.
• Suitable masking materials of an insulative nature are the organic chelates or coordination compounds and amine derivatives, such as amine salts or quaternaries, including the Werner type chromium of fatty acids (e.g. Quilon chrome complex, a product of E. I. du Pont de Nemours and Co., Wilmington, Delaware), various fatty amine derivatives (e.g. Armeens and Arquads, Armour Industrial Chemical Co., Chicago, Illinois), amine containing resins (e.g. Versamid resins, General Mills, -Inc., Minneapolis, Minnesota), condensation products of polymerized unsaturated fatty acids (e.g. 'dilinoleic acid) with aliphatic amines (e.g.
• amine salts or quaternaries including the Werner type chromium of fatty acids (e.g. Quilon chrome complex, a product of E. I. du Pont de Nemours and Co., Wilmington, Delaware), various fatty amine derivatives (
• ethlylene diarnine polyethylene, polytetrafluoroethylene, polytrifluorochloroethylene, synthetic rubbers, polyvinyl acetate, polystyrene, butadiene-styrene copolymers, butadiene-acrylic acid copolymers, natural rubber, polyviny-lidene chloride, etc.
• Electrolytic immobilization also provides a method for creating an 'imagewise coating of vaporizable image forming reactant on the copysheet surface.
• this method generally involves a change in vaporizability of the image former.
• the copysheet surface may be coated with a vaporizable image former which forms a complex or chelate of lower vaporizability, e.g. chelating or complexing of a phenolic reducing agent, coated uniformly over the copysheet surface, by cathodic electrolysis of a metal ion that complexes with the phenolic reducing agent.
• a copysheet is uniformly coated with catechol and exposed to a light image
• cathodic electrolysis with an electrolytic bath containing ferrous or ferric ion produces a colored complex in the more conductive (and more alkaline) areas of the copysheet surface.
• This complex has significantly lower vaporizability than the cate chol.
• the catechol reduces a material, such as silver behenate, or forms a complex with another material thereon to produce a visible image.
• the vaporizable image forming material may be coated uniformly in a thin tfilm over the photoconductive surface of the copysheet after exposure to the light image and before electrolysis.
• the film of vaporizable image forimng material is relatively transparent to the activating irradiation incident to exposure and creation of a differential conductivity image pattern on the copysheet, it may of course be present over the photoconductive surface before exposure. It has been found that extremely small amounts of the vaporizable image forming material uniformly distributed over the copysheet surface are effective for the thermal preparation of multiple copies from the copysheet in this manner.
• the vaporizable image forming material may also be included in a coating in or near the surface of the photoconductive copysheet.
• Both positive and negative prints can be obtained on the receptor sheets.
• the receptor sheet contains a colored coreactant which is rendered colorless by reaction with a reducing agent vaporized from the more conductive areas of the copysheet, a positive of the original radient image may be obtained.
• the coreactant is reduced to a more intensely colored product, a negative print may be obtained.
• Methylene -blue, Crystal Violet and Malachite green when contained in the receptor sheet, are examples of coreactants which are converted to a colorless form upon reduction.
• Silver behenate and tetrazolium compounds exemplify coreactants which become more intensely colored upon contact with a vaporized reducing agent.
• the photoconductive copysheet After the photoconductive copysheet has been exposed to the irradiant image, or simultaneous therewith, it is electrolytically developed to provide a difierential deposit of vaporizable image forming material on the photoconductive surface using any of the electrolytic deposition or electrolytic modification techniques described earlier.
• the copysheet is then placed in close proximity to, preferably in physical contact with, a receptor sheet.
• Heating the copysheet slightly above the vaporization point of the vaporizable image former typically by passing both the copysheet and the superimposed receptor sheet through a heated mangle, ironing device or commercial thermographic copying machine with the heat being preferably applied to the backside of the photoconduct-ive copysheet, vaporizes the image forming material and affects its vapor transfer into 7 the adjacent receptor sheet.
• This vapor transfer step can be repeated with one or more receptor sheets to make multiple copies from the photoconductive copysheet master until the vapor supply is exhausted.
• the application of heat to the copysheet also tends to erase the differential conductivity pattern thereon, thus in some cases permitting reuse of the copysheet upon exhaustion of the vaporizable image former on its surface.
• Apparatus suitable for heating the copysheet may conveniently consist of a line source of light including a tubular bulb having a linear filament and mounted within a focused reflective housing, as described in United States Patent Number 2,740,895. Another suitable form of apparatus is described in United States Patent Number 2,891,- 165. A heated platen may also be employed.
• Example I This example illustrates the cathodic electrolytic deposition of an organic reducing agent.
• a photoconductive copysheet containing a strongly photoconductive layer of zinc oxide and butadiene-styrene copolymer (30:70 mol ratio) in a pigment to binder ratio of about 4/ 1 as binder on an aluminum foil backin-g was exposed to a visible light image.
• the exposed copysheet was electrolytically developed, the aluminum backing being connected as cathode, by slowly passing a sponge developer roller (anode) over the surface with the application of a 40 Volt DC. electrical potential.
• the sponge developer roller contained a 5% aqueous solution of lethyl pyridinium bromide.
• the thus developed copysheet was then placed against a paper receptor sheet containing silver behenate and heated between metal plates for ap-v proximately one second at 120 C.
• Hot rollers or any other means for uniformly heating the copysheet for a specific time interval may also be used.
• a brown-black negative image is developed on the receptor sheet. This operation can be repeated to obtain further copies in the same manner and permits the preparation of multiple enlarged prints from a microfilm transparency.
• the final prints on apaque receptor sheet material are directly readable if the original visible light image is a mirror image of the desired print.
• Example II This example illustrates the preparation of a transparency using the cathodic electrolytic deposition of an organic reducing agent.
• a transparent receptor sheet was made by coating a polyethylene terephthalate film with an alcoholic solution of triphenyl tetrazolium and butyral polyvinyl plastic. Following the procedure set forth in Example I, a negative transparency was produced on the receptor sheet after heat treatment at C.
• Example III This example illustrates the preparation of a positive transparency or opaque print using electrolytic deposition of an organic reducing agent.
• a receptor sheet previously primed with colloidal silica was treated with a 3% solution of crystal violet in ethyl alcohol to form a blue colored receptor sheet.
• a photoconductive zinc oxide copysheet was then exposed to a visible light image and electrolytically developed with a 5% solution of l-ethyl pyridinium iodide in the manner described in Example I.
• the exposed copysheet was then placed against the blue colored receptor sheet and heated briefly to C. A positive white on blue copy was obtained, the crystal violet being reduced to leuco form in the areas corresponding to the visible light struck areas of the photoconductive copysheet.
• Example I V This example illustrates the electrolytic deposition of a vaporizable dyestuff.
• the copysheet was then removed from the electrolytic bath, the dyed surface placed in contact with a paper receptor sheet, and heat was applied uniformly over the back of the copysheet (about 250 C.). After separating the sheets a yellow image corresponding to the original light image was formed on the receptor sheet.
• Example V This example illustrates the electrolytic deposition of a vaporizable chelating agent.
• the back of the copysheet was heated briefly and uniformly to 250 C. Upon separating the sheets, the receptor sheet was observed to contain a red image formed from the nickel-dimethylglyoxime complex. Ten copies were prepared from this copysheet by repeating the heating sequence with further similar receptor sheets.
• Example VI This example illustrates the electrolytic destruction technique in which an organic vaporiza'ble reducing agent is selectively oxidized in a high pH environment.
• a photoconductive copysheet having a coating of zinc oxide and butadiene-styrene copolymeric binder (4/ 1 wt. ratio) on an aluminum foil backing was coated with a thin film of 4-methoxy naphthol and buffed lightly to insure a thin continuous coating.
• the copysheet was dark adapted and exposed to a light image.
• a porous plastic (Porelon) roller containing a 5% aqueous solution of cesium nitrate was passed slowly over the surface.
• the anode was embedded in the roller.
• the potential applied was 40 volts D.C.
• the copysheet was then placed adjacent to a paper receptor sheet containing silver behenate and heated at 120 C. to form a visible blue-black positive image on the receptor sheet. The heating step was repeated to provide multiple copies.
• electrolytes are ioniza'ble salts of barium, magnesium, calcium, potassium and sodium. Hydroquinone operated in similar. fashion when used in place of 4- methoxy naphthol.
• Example VII This example will illustrate electrolytic immobilization by means of chelate formation.
• the porous roller contained a 5% aqueous solution of ferrous ammonium sulfate.
• the electrolyzin-g voltage was 20 volts D.C.
• the ferrous ion reacted with the catechol in the light struck areas, forming a colored complex having a lower vaporizability than catechol.
• the electrolytically developed copysheet was placed adjacent a receptor sheet containing silver behenate and heated to C., a positive visible image was produced on the receptor, the silver behenate being reduced by vaporized catechol.
• a dithiooxamide can be electrolytically complexed with nickel, using an aqueous nickel salt electrolyte, and the uncomplexed dithiooxamide can be vapor transferred to a receptor sheet containing a complexible nickel salt, producing a positive print.
• Example VIII This example illustrates electrolytic destruction by anodic electrolytic oxidation of a vaporizable reducing agent.
• a photoconductive zinc oxide copysheet similar to that described in Example I was uniformly vapor coated on the zinc oxide surface with aluminum, the aluminum layer having a 30% transmissivity to visible light from a tungsten source.
• the vapor coated surface was then coated by buffing with 4-methoxy-l-naphthol, and the resulting sheet was exposed to a light image.
• electrolytic development was efit'ected for 3 seconds at 40 volts D.C., using a 5% aqueous solution of sodium acetate as the electrolytic bath. This resulted in the selective oxidation of the 4-methoxy-l-naphthol in the light struck, and hence more conductive, areas of the copysheet surface.
• this sheet was then placed in contact with a paper receptor sheet containing silver behenate and heated at 120 C., a positive image was formed on the receptor.
• photoconductive copysheets having a coating of carbon black in a butadiene-styrene copolymer rnatrix (10-20% transmissivity to visible light) instead of vapor coated aluminum.
• Vapor coated semiconductors such as p-type lush, and other materials having relatively low lateral and relatively high transverse electrical conductivity may also be used as topcoatings for the photoconductive layer, provided such layers permit transmission of sufiicient radient energy to activate the underlying photoconductive layer.
• Example 1X This example illustrates electrolytic masking.
• a photoconductive Zinc oxide copysheets as described in Example I, was surface coated with DuPont Oil Yellow N (Color Index 11020). The copysheet was then exposed to a visible light image, forming a corresponding conductive pattern thereon. With the electrically conductive substrate of the copysheet connected as cathode, electrolytic development was effected for 3 seconds at 45 volts DJC. using a 3% water dispersion of colloidal alumina (AlOOI-I) as the electrolytic bath. The positively charged alumina particles deposited selectively on the more conductive areas of the copysheet surface, forming a barrier coating over the yellow dye. This developed sheet was then placed in contact with an ordinary sheet of paper and heated at 250 C. to form a positive dye image on the paper surface.
• DuPont Oil Yellow N Color Index 11020
• Example X This example illustrates electrolytic destruction by selective anodic oxidation of a reducing agent.
• the copysheet can be coated with quinone and cathodically electrolyzed to form hydroquinone on the light struck areas.
• Example XI This example illustrates electrolytic modification by cathodic electrodeposition of an oxidizing agent and the oxidation thereby of a vaporizable reducing agent.
• the nickel chloride can be replaced with CoCl or MnCl which also form relatively water insoluble metal chromates.
• the electrically conductive backing of the copysheet was connected as cathode during electrolysis (40 volts DC. for about 3 seconds). During cathodic electrolysis the more conductive areas of the copysheet surface became more alkaline, and insoluble nickel chromate precipitates selectively On those surface areas. After the electrolytic step is completed, the copysheet surface is buffed lightly with 4methoxy naphthol.
• the 4-methoxy naphthol is oxidized.
• the copysheet was placed adjacent a receptor sheet containing silver behenate and heated to about 120 C. for several seconds, the unoxidized 4-methoxy naphthol in the background areas vapor transferred to the receptor and reduced the silver behenate to free silver, forming a positive print.
• vaporizable reducing agents such as hydroquinone
• hydroquinone the oxidation product, i.e. quinone
• a receptor sheet containing an oxidizable material e.g. leuco Malachite green (Color Index 4200).
• the top coated copysheet was allowed to dry under ordinary room conditions for several hours, it was exposed to a light pattern and was then cathodically electrolyzed for 1 to 3 seconds (40 volts DC.) in a aqueous solution of ethyl pyridinium bromide.
• the electrolyzed copysheet had dried, it was placed adjacent a paper receptor sheet containing nickel stearate and was heated at about C. for several seconds.
• a blue positive image was formed on the receptor sheet, the vaporized dithiooxamide from the copysheet background areas reacting with the nickel stearate to form a blue nickel complex. No dithiooxamide transferred from the light struck areas of the copysheet.
• An image reproduction process which comprises exposing to activating irradiation a photoconductive, electrolytically developable copysheet to produce a differential conductivity pattern thereon, electrolytically depositing from an electrolytic bath a vaporizable image forming material selectively on the more conductive areas of said copysheet, positioning the electrolytically developed copysheet adjacent a surface of a receptor sheet capable of changing color upon contact with said vaporizable image forming material, and heating said copysheet sufiiciently to effect vapor transfer of said vaporizable image forming material to said receptor surface, thereby creating a visible image on said receptor surface corresponding to said differential conductivity pattern.

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• 1962
  • 1962-03-22 US US181796A patent/US3363556A/en not_active Expired - Lifetime
• 1963
  • 1963-02-22 DE DE19631497011 patent/DE1497011A1/de active Pending
  • 1963-03-21 CH CH358863A patent/CH426901A/de unknown
  • 1963-03-22 GB GB11559/63A patent/GB1041404A/en not_active Expired
  • 1963-03-22 SE SE3134/63A patent/SE309534B/xx unknown

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