Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/02—Charge-receiving layers
  • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
  • G03G5/06—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being organic
  • G03G5/0601—Acyclic or carbocyclic compounds
  • G03G5/0618—Acyclic or carbocyclic compounds containing oxygen and nitrogen
• • 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
  • G03G13/04—Exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
• • 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
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/02—Charge-receiving layers
  • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
  • G03G5/06—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being organic
  • G03G5/0601—Acyclic or carbocyclic compounds
  • G03G5/0609—Acyclic or carbocyclic compounds containing oxygen
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/02—Charge-receiving layers
  • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
  • G03G5/06—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being organic
  • G03G5/0622—Heterocyclic compounds
  • G03G5/0624—Heterocyclic compounds containing one hetero ring
  • G03G5/0627—Heterocyclic compounds containing one hetero ring being five-membered
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/02—Charge-receiving layers
  • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
  • G03G5/06—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being organic
  • G03G5/0622—Heterocyclic compounds
  • G03G5/0624—Heterocyclic compounds containing one hetero ring
  • G03G5/0635—Heterocyclic compounds containing one hetero ring being six-membered
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/02—Charge-receiving layers
  • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
  • G03G5/06—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being organic
  • G03G5/07—Polymeric photoconductive materials
  • G03G5/071—Polymeric photoconductive materials obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • G03G5/072—Polymeric photoconductive materials obtained by reactions only involving carbon-to-carbon unsaturated bonds comprising pending monoamine groups
  • G03G5/073—Polymeric photoconductive materials obtained by reactions only involving carbon-to-carbon unsaturated bonds comprising pending monoamine groups comprising pending carbazole groups

Definitions

• photoconductive members are highly useful in electrophotographic processes requiring persistent photoconductivity.
• This invention relates to organic photoconductors and, more particularly, to organic photoconductive compositions for use in processes in which the conductivity of the photoconductor must persist after exposure of the photoconductor to light.
• An example of such a persistent photoconductivity process comprises exposing an inorganic photoconductive phosphor, such as zinc cadmium sulfide to a light pattern, whereby a latent conductivity image is formed in the exposed areas of the phosphor.
• the phosphor then is electrostatically charged in the dark and an electrostatic pattern is formed on the non-conductive areas of the phos phor.
• the electrostatic charge pattern is developed with toner by one of the conventional methods.
• organic photoconductive compositions which contain both a dyestuff and an activator selected from the group consisting of organic carboxylic acids, nitrophenols, nitroanilines, and carboxylic acid anhydrides, require only extremely short exposure times, have relatively long persistent conductivity and the persistent conductivity can rapidly be erased by heat.
• the organic photoconductive compositions of the present invention can be used in the above-described process of exposure, charging, and developing, or the compositions can be used in the persistent photoconductive process described in the copending application Ser. No. 474,583, filed July 26, 1965. Further, these materials can be used in conjunction with a toner transfer process, in which the toner of the developed image on the, photoconductive composition is transferred to paper, and in conjunction with a charge transfer process in which the electrostatic charge pattern is transferred to a dielectric paper.
• organic photoconductors which can be used in the present invention include what can be termed small molecule photoconductors dispersed in a binder, and polymeric photoconductors which can be self supporting.
• Suitable binders for use with the small molecule photoconductors comprise polymers having fairly high dielectric strength and which are good electrically insulating film-forming vehicles.
• Materials of this type comprise styrene-butadiene copolymers; silicone resins; styrenealkyd resins; soya-alkyd resins; polyvinyl chloride; polyvinylidene chloride; vinylidene chloride-acrylonitrile copolymers; polyvinyl acetate; vinyl acetate-vinyl chloride copolymers; polyvinyl acetals, such as polyvinyl formal; polyacrylic and methacrlic esters, such as polymethyl methacrylate, poly n butyl methacrylate, polyisobutyl methacrylate, etc.; polystyrene; nitrated polystyrene; polymethylstyrene; isobutylene polymers; polyesters, such as polyethylene alkaryloxyalky
• Suitable polymeric photoconductors are, for example, poly N acrylylphenothiazine, poly N-(B-acrylyloxyethyl)-phenothiazine, poly N (2-acrylyloxy propyl)- phenothiazine, polyallylcarbazole, poly-N-2-acrylyloxy-2- methyl-N-ethyl carbazole, poly N(2 p-vinylbenzoylethyl)-carbazole, poly-N-propenylcarbazole, poly-N-vinylcarbazole, poly N Z-methacrylyloxypropyl carbazole, poly-N-acrylylcarbazole, poly-4 vinyl p-(-Ncarbazyl)- toluene, poly (vinylanisal acetophenone), and polyindenes.
• the monomers of the polymeric photoconductors can be copolymerized with each other or with other monomers, such as vinyl acetate, methylacrylate, vinylcinnamate, polystyrene, Z-Vinylpyridine.
• Sensitivity of the above organic photoconductors can be extended from the ultraviolet into the visible range of the electromagnetic spectrum by the addition of a dyestuff sensitizer and preferably a cationic dyestuff sensitizer.
• the persistent photoconductivity properties of these organic photoconductors can be improved by the addition of an activator selected from the group consisting of organic carboxylic acids, nitrophenols, nitroanilines, and carboxylic acid anhydrides.
• the quantity of the dyestutf sensitizer added to the photoconductor ranges from about 0.01 to about 5%, with the preferred range being from 0.5 to about 3%.
• the quantity of activator added to the organic photoconductor varies according to the compound used and ranges from about 0.1 to about The preferred amount for most of the compounds is about 4%. Mixtures of several activators and several dyestuffs may be used in place of a single activator in a single dyestufi.
• dyestuff sensitizers examples include triarylmethane dyestuffs such as Malachite Green, Brilliant Green, Victoria Blue B, Methyl Violet, Crystal Violet, Acid Violet 6B; xanthene dyestuffs, namely rhodamines, such as Rhodamine B, Rhodamine 6G, Rhodamine G Extra, and Fast Acid Eosin G, as also phthaleins such as Eosin S, Eosin A, Erythrosin, Phloxin, Rose Bengal, and Fluorescein; thiazine dyestuffs such as Methylene Blue; acridine dyestuffs such as Acridine Yellow, Acridine Orange and Trypaflavine; and cyanine dyestuffs such as Pinacyanol, Cryptocyanine and Cyanine.
• triarylmethane dyestuffs such as Malachite Green, Brilliant Green, Victoria Blue B, Methyl Violet, Crystal Violet, Acid Violet 6B
• Activators of the present invention are: organic carboxylic acids, such as benzoic acid, phthalic acid and tetrachlorophthalic acid, dibromomaleic acid, 2-bromobenzoic acid, 2-nitrobenzoic acid, 3-nitrobenzoic acid, 4- nitrobenzoic acid, 3-nitro-4-ethoxybenzoic acid, 2-chloro- 4-nitrobenzoic acid, 3 nitro-4-methoxybenzoic acid, 4- nitro-l-methylbenzoic acid, 2-chloro-5-nitrobenzoic acid, 3-chloro-6-nitrobenzoic acid, 4-chloro-3-nitrobenzoic acid, 5-chloro-3-nitro-2-hydroxybenzoic acid, 4 chloro-2-hydroxybenzoic acid, 2,4-dinitrobenzoic acid, 2-bromo-5- nitrobenzoic acid, 2-cyanocinnamic acid, 2,4-dichlorobenzoic acid, 3,5-dinitrobenzoic acid, 3,5-dinitrosalicylic acid, malic
• the organic photoconductive composition is carried on a support having a surface resistivity of about 1 to 10 megohms per square.
• supporting materials are conductive paper and metals, such as copper, aluminum, zinc, tin, iron and lead. If the process includes contact reflex exposure instead of optical exposure, the support should be substantially transparent.
• a layer of polyethylene terephthalate coated with a thin layer of aluminum or copper and NESA glass are examples of transparent supports.
• Solvents for preparing coatings of the organic photoconductive compositions include benzene, toluene, acetone, 2-butanone, chlorinated hydrocarbons, e.g., methylene chloride, ethylene chloride, etc., ethers, e.g., tetrahydrofuran, or mixtures of these solvents, etc.
• the prepared coatings can be applied on the support in any well known manner, such as doctor-blade coating, spin-coating, dip-coating, and the like.
• This persistent conductivity must be erased before the photoconductive composition can be re-exposed. Otherwise, the second exposure will be superimposed on the first exposure.
• This erasure is accomplished, according to the present invention, by heating the photoconductive composition for not longer than about 5 seconds.
• the preferred erasure temperature range is about C. to about 150 C. with the preferred temperature being C.
• suitable heating means for erasing the persistent conductivity in the photoconductor For example, a heating element, such as a plate, can be used or the photoconductor can be passed through heated rollers at a linear velocity of 20 feet per minute, both the plate and the rollers being within the above temperature range.
• Other heating means includes an AC. electric field to cause induction heating.
• negative toner means toner which is attracted to a positive electrostatic charge or which is negatively charged.
• Positive toner means toner which is positively charged or attracted to a negative electrostatic charge.
• EXAMPLE I The following is a comparison between essentially the same persistant conductive composition of Example I of British Pat. 977,200 and the same composition to which is added one of the activators of the present invention.
• Two photoconductive compositions were prepared.
• One composition contained 1 gm. of polyvinyl chloride (dissolved in tetrahydrofuran), 1 gm. of 2,5-bis(4-dimethylaminophenyl-l)-l,3,4-oxadiazole (dissolved in 1,1,2,2'- tetrachloromethane) and .01 gm of a dyestulf, Rhodamine B.
• the other photoconductive composition was the same except it included .06 gm. of 2,2',4,4,6,6'-hexanitrodiphenylamine, one of the activators of the present invention.
• the oxadiazole contained diethyl substituents rather than dimethyl substituents.
• Both of the photoconductive compositions were coated on aluminum slides with a doctor blade set at a 5 mil wet gap.
• a photoconductor of the present invention was prepared in the following manner: 40 mg. of 3,5-dinitrobenzoic acid was dissolved in 14.3 grams of a 5.3% polyvinyl carbazole solution of 1,2-dichloroethane. To this was added 10 mg. of Malachite Green oxalate dye which was dissolved in 1.0 ml. of 50% each of methylethyl ketone and methyl alcohol. To insure proper mixing, the prepared solution was agitated for about one hour. Then, the solution was coated on an aluminum plate using a doctor blade set at 7 ml. wet gap. The resulting dried photoconductive coating was approximately 9 microns thick.
• the prepared photoconductor was exposed to a 40 watt incandescent lamp at a distance of 14 inches through a positive master for one second.
• An insulating material of polyvinyl acetate which was part of a continuous roll was brought into contact with the exposed photoconductor and the two of them passed between a pair of conductive rollers having a 700 volt D.C. potential.
• the polarity of the roller in contact with the photoconductor was negative.
• the insulating material was separated from the photoconductor and a negative electrostatic pattern was formed on the insulating material corresponding to the exposed areas of the photoconductor.
• the exposed photoconductor was repeatedly brought into contact with other portions of the continuous roll of insulating material and passed through the rollers with the voltage applied (as stated above) until 48 positive electrostatic charge patterns were prepared. These charge patterns then were developed with negative toner using a biased magnetic brush to yield 48 positive copies of the positive image.
• EXAMPLE III The photoconductor of Example II was prepared. This photoconductor was exposed to a 40 Watt incandescent lamp at a distance of 14 inches through a positive master for 0.25 second. Then, the exposed photoconductor was passed under a corona discharge unit having a potential of +6000 volts and a positive electrostatic charge pattern formed on the surface of the exposed photoconductor. The exposed and charged photoconductor was cascade developed with a negative toner, the toner being attracted to the unexposed areas to yield a positive copy.
• An insulating sheet of polyvinyl acetate was brought into contact with the exposed coating and the two of them passed between a pair of conductive rollers having an applied potential of 600 volts, the polarity of the roller in contact with the photoconductor being positive.
• the insulating sheet and photoconductor were separated and a positive electrostatic pattern corresponding to the exposed areas of the photoconductor is formed on the insulating sheet.
• the electrostatic image on the insulating sheet then was developed by magnetic brush carrying a positive toner to form unfixed positive copy.
• a sheet of common stock paper was brought into contact with the unfixed toner image and by applying pressure, the toner image was transferred to the paper and fixed by heating.
• EXAMPLE V A solution was prepared by dissolving 20 mg. of tetrachlorophthalic anhydride and 5 mg. of Malachite Green oxalate in 7 g. of a 5.3% polyvinyl carbazole solution of dichloroethane. The solution was coated on an aluminum plate using a doctor blade set at a 7 mil wet gap. The prepared photoconductor then was exposed to a 100 watt incandescent lamp for 5 seconds at a distance of 14 inches through a positive image.
• the exposed photoconductor was brought into contact with an insulating sheet of polyvinyl acetate and the two of them passed between conductive rollers having an applied voltage of 900 volts, the polarity of the roller in contact with the photoconductor being negative.
• the photoconductor and insulating sheet were separated and a negative electrostatic charge pattern was formed on the insulating sheet corresponding to the exposed areas of the photoconductor.
• the electrostatic charge pattern was cascade developed with a negative toner composition to form a positive copy.
• EXAMPLE VI The photoconductor of Example V was exposed to a 40 watt incandescent lamp for two seconds at a distance of 12 inches through a positive master. Following this, the photoconductor was electrostatically charged with a corona discharge unit having a potential of 6000 volts. The negative electrostatic charge pattern which formed on the photoconductor was cascade developed with positive toner and the unfixed toner image was transferred to paper.
• EXAMPLE VII instead of using a polymeric photoconductor, a small molecule photoconductor was prepared as follows: 0.5 g. of 1-phenyl-3 (4'-dimethylaminostyryl) 5 (4"-dimethylaminophenyl)pyrazoline was dissolved in a 10% solution of polystyrene in benzene. To this solution was added 10 mg. of 3,5-dinitrobenzoic acid and 5 mg. of Malachite Green, which was dissolved in 0.5 ml. of 50% each methylethyl ketone and methyl alcohol. This solution was coated on an aluminum strip using a doctor blade set at a 5 mil wet gap.
• the prepared photoconductor was exposed for 5 seconds to a 25 watt incandescent lamp at a distance of 14 inches through a negative image.
• An insulating sheet of polystyrene was brought into contact with the photoconductor and the two of them passed through conductive rollers with an applied potential of 700 volts, the polarity of the rollers in contact with the photoconductor being positive.
• the insulating sheet was separated from the photoconductor and a positive electrostatic charge pattern corresponding to the exposed area of the coating was formed on the insulating sheet.
• the electrostatic charge pattern was developed by a magnetic brush carrying a negative toner to form a positive copy.
• EXAMPLE VIII The photoconductor of Example VII was prepared. This photoconductor was exposed through a positive master for 0.25 second to a 250 watt photoflood light source at a distance of 14 inches. The photoconductor then was electrostatically charged with a corona discharge unit having a potential of +6000 volts and a positive electrostatic charge pattern formed on the photoconductor. The charge pattern was cascade developed with negative toner to yield a positive copy of the master.
• EXAMPLE IX Another small molecule photoconductor was prepared by dissolving 0.5 g. of 1-phenyl-3-(4'-dimethylaminostyryl)-5-(4"-dimethylaminophenyl)pyrazoline in 2.5 g. of polystyrene (20% soln.) in benzene. To this solution was added 0.03 g. 4,4,6,6'-tetranitrodiphenic acid and 0.005 g. Malachite Green oxalate in 5 ml. of dichloroethane. The solution was coated on an aluminum plate with a 8 mil gap.
• the prepared photoconductor on the plate was exposed for 5 seconds to a 40 watt incandescent lamp at a distance of 12 inches through a positive master.
• a 40 watt incandescent lamp at a distance of 12 inches through a positive master.
• the photoconductor and the sheet were passed between conductive rollers with an applied potential of 900 volts, the rollers in contact with the photoconductor being negative.
• the sheet separated from the coated slide and a negative electrostatic pattern corresponding to the exposed areas of the coating was formed on the insulated sheet.
• Ten electrostatic patterns were formed by bringing the exposed photoconductor sequentially into contact with other portions of the continuous roll and passing them through the conductive rollers, as described above. After ten electrostatic patterns were formed, these patterns were developed by cascade development using a negative toner to form ten positive copies.
• EXAMPLE X The photoconductor of Example IX was prepared. This photoconductor was exposed through a positive master to a 40 watt incandescent lamp at a distance of 12 inches for 0.5 second. Using a corona discharge unit having a potential of 1+ 6000 volts, a positive electrostatic charge was applied to the exposed photoconductor. The electrostatic charge pattern which formed was cascade developed with negative toner and the toned image was transferred to paper and fixed by heating.
• a photoconductor was prepared by dissolving 0.13 g. of 1,3-diphenyl-5-(4'-dimethylaminophenyl)pyrazoline in 2.5 g. of 20% polystyrene in benzene. To this solution was added 0.005 g. of picric acid and 0.005 g. Malachite Green oxalate in 5 ml. of 1,2-dichloroethane. The solution wos coated on an aluminum plate with a 5 mil gap. The prepared photoconductor on the plate was exposed for 10 seconds to a 100 watt incandescent lamp at a distance of 12 inches through a negative master.
• the photoconductor and the sheet were passed between conductive rollers with an applied potential of 900 volts, the rollers in contact with the photoconductor being positive.
• the sheet separated from the photoconductor and a positive electrostatic pattern corresponding to the exposed areas of the coating was formed on the insulated sheet.
• the electrostatic charge pattern was developed by magnetic brush development using a negative toner to form a positive copy.
• EXAMPLE XII The photoconductor of Example XI was prepared. This photoconductor was exposed through a positive master to a 40 watt incandescent lamp at a distance of 12 inches for two seconds. Using a corona discharge unit having a potential of +6000 volts, an electrostatic charge was applied to the exposed photoconductor. The positive electrostatic charge pattern which formed was cascade developed with negative toner to yield a positive copy of the master.
• EXAMPLE XII'I A solution of 0.8 g. of 1, 3, 4, S-tetraphenyl-imidazole- 2-thione, 0.5 g. of methylal of polyvinyl alcohol in 2 g. of methylethyl ketone was prepared. To this solution was added 0.03 g. 4,4,6,6-tetranitrodiphenic acid and'0.008 g. Ethyl Violet in 0.5 ml. of 50% each methylethyl ketone and methanol. The solution was coated on an aluminum plate with a 3 mil gap. This photoconductor was exposed for 1 second to a 375 watt incandescent lamp at a distance of 12 inches through a negative master.
• the photoconductor and the sheet were passed between conductive rollers with an applied potential of 600 volts, the rollers in contact with the photoconductor being positive.
• the sheet was separated from the photoconductor and a positive electrostatic pattern corresponding to exposed areas of the coating was formed on the insulated sheet.
• the electrostatic charge pattern was developed by magnetic brush development using a negative toner to form a positive copy.
• a photoconductive formulation was prepared by adding 14.3 g. of a 5.3% polyvinyl carbazole solution of 1,2-di chloroethane to 1 ml. of a solution of 7.5 mg. of Malachite Green oxalate in a 50% methylethyl ketone and methyl alcohol, having dissolved therein 30 mg. of 3,5- dinitrobenzoic acid.
• the photoconductive formulation was agitated for one hour.
• the photoconductor was coated on a semi-transparent aluminized polyethylene terephthalate using a doctor blade at 8 mil wet gap.
• the resulting dried photoconductive coating was roughly 10 microns thick.
• This photoconductor was placed face down in intimate contact on a positive master and exposed to filtered light (4,000 to 5,800 A.) from a 500 watt incandescent lamp at a distance of 14 inches.
• An insulating material of polyvinyl acetate which was part of a continuous roll, was brought into contact with the contact reflex exposed photoconductor and the two of them passed between a pair of conductive rollers having a 900 volt potential. The polarity of the roller in contact with the photoconductor was negative.
• the insulating material was separated from the photoconductor and a negative electrostatic pattern was formed on the insulating material corresponding to the exposed areas of the photoconductor. This charge pattern then was developed with a negative toner using a biased magnetic brush to yield a positive copy of the master. Ten copies from the same exposure were made by the above procedure.
• EXAMPLE XV A photoconductor having the same formulation as Example II, was exposed for 8 seconds to a negative master by an incandescent light source of 40 watts at a distance of 14 inches. The exposed photoconductor was attached to the upper roller of a pair of conductive rollers having a 700 volt potential across them, the upper roller being at a positive potential. A roll of insulating material of polyvinyl acetate was positioned to feed between the two rollers. By rotating the upper roller 100 times, 100 electrostatic patterns were formed on the insulating material. These positive charge patterns were developed with a magnetic brush using negative toner to form 100 positive copies of the negative master.
• EXAMPLE XVI To obtain copies of two different masters, the photoconductor of the formulation of Example II, was exposed to the positive master of Example II and the procedure of that example was followed to make a copy of the master. The exposed photoconductor having a persistent conductivity image therein, then was passed through heated rollers at 120 C. at a linear velocity of 20 feet per minute. The heating erased the persistent conductivity image in the photoconductor. This photoconductor then is exposed to the negative master of Example IV and the procedure of that example followed to form a copy of that master.
• a photoconductive composition was prepared consisting of 0.5 gm. of 1,3-diphenyl--(p-dimethylamino)- phenylpyrazoline, 2 gms. of polystyrene, 5 ml. of dichloroethane, 0.03 gm. of 2,2,4,4',6,6-hexanitrodiphenylamine and 0.005 gm. of Malachite Green oxalate.
• This photoconductive composition was coated on an aluminum slide using a doctor blade set at a 7 mil wet gap. The prepared photoconductor was exposed for one second to a 40 watt tungsten bulb at 14 inches through a positive master.
• the exposed photoconductor was brought into contact with an insulating sheet of polyvinyl acetate and the two of them passed between conductive rollers having applied voltage of 600 volts, the polarity of the roller in contact with the photoconductor being negative.
• the photoconductor and insulating sheet were separated and a negative electrostatic charge pattern was formed on the insulating sheet corresponding to the exposed areas of the photoconductor.
• the electrostatic charge pattern was magnetic brush developed with a negative charged toner to form a positive copy of the master.
• EXAMPLE XVIII A photoconductive composition was prepared by using 0.5 gm. of 1,3,5-triphenyl pyrazoline, 5 gms. of 10% polystyrene, 0.03 gm. of 2,2',4,4',6,6'-hexanitrodiphenylamine, 0.005 gm. Malachite Green oxalate, and 5 ml. of dichloroethane. The photoconductive composition was coated on an aluminum slide with a doctor blade set at a 7 mil wet gap. Using the same procedure of Example XVII except the prepared photoconductor was exposed for 4 seconds, a negative electrostatic charge pattern was formed on the insulating sheet. This charge pattern was developed with negatively charged toner using cascade development to yield a positive copy of the master.
• a photoconductive composition was prepared which included 14.3 gms. of 7% polyvinyl carbazole, .04 gm. of 2,2',4,4',6,6'-hexanitrodiphenylamine and 0.01 gm. of Malachite Green oxalate.
• the photoconductive composition was coated on an aluminum slide using a doctor blade set at a 7 mil wet gap.
• the prepared photoconductor was exposed to a 40 watt tungsten bulb for 2 seconds at a distance of 12 inches through a negative master. The exposed photoconductor was brought into contact with an insulated sheet of polyvinyl acetate.
• the two of them passed between conductive rollers having applied voltage of 900 volts, the polarity of the roller in contact with the photoconductor being positive.
• the photoconductor and the insulating sheet were separated and a positive electrostatic charge pattern was formed on the insulating sheet corresponding to the exposed area of the photoconductor.
• the electrostatic charge pattern was cascade developed with negative toner to form a positive copy of the negative master.
• EXAMPLE XX A photoconductor was prepared in the following manner: 40 mg. of 3,5-dinitrobenzoic acid was dissolved in 14.3 gms. of a 7% polyvinyl carbazole solution of 1,2-dichloroethane. To this was added 10 mg. of Malachite Green oxalate dye which was dissolved in 1 ml. of 50% each of methyl ethyl ketone and methyl alcohol. This prepared solution was coated on a stainless steel substrate using a doctor blade set at 7 mil wet gap. The prepared photoconductor was exposed to a 40 watt tungsten bulb at a distance of 14 inches to a positive master for 2 seconds.
• An insulating material of polyvinyl butyral having a high calender paper base and being part of a continuous roll was brought into contact with the exposed photoconductor and the two of them passed between a pair of conductive rollers having a 700 volt D.C. potential. The polarity of the roller in contact with the photoconductor was negative. Immediately after passing through the rollers and with the voltage still applied, the insulating material was separated from the photoconductor and a negative electrostatic charge pattern was formed on the insulating material corresponding to the exposed area of the photoconductor. The exposed photoconductor was brought into contact with other portions of the continuous roll of insulating material and passed through the rollers with the voltage applied (as stated above) until 5 negative electrostatic charge patterns were prepared. These charge patterns were developed with negative toner using a bias magnetic brush to yield 5 positive copies of the positive master. The quality of the fifth copy was excellent.
• a photoconductive composition was prepared by using 0.5 gm. 1-formyl-2,5-(bis-p-dimethylaminophenyl)-1,3,4- triazole, 5 gms. of 10% polyvinyl formal, 0.02 gm. 2,2, 4,4',6,6-hexanitrodiphenylamine, 0.005 gm. Malachite Green oxalate and 5 ml. of methanol.
• This photoconductive composition was coated on an aluminum slide using a doctor blade set at 7 mil wet gap.
• the prepared photoconductor was exposed for 0.5 second to a 250 watt photofiood lamp at a distance of 14 inches through a positive master.
• the exposed photoconductor was negatively electrostatically charged with a corona discharge unit having -6500 volt potential.
• the electrostatic charge pattern formed on the photoconductor was cascade developed with positively charged toner to yield a positive copy of the postive master.
• an organic photoconductive layer comprising polyvinyl carbazole, a dyestufi sensitizer, and a dinitro-substituted benzoic acid, to electromagnetic radiation to which said layer is sensitive, whereby a latent conductive pattern is produced in the exposed areas of said layer and remains after the electromagnetic radiation is removed;

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• 1965
  • 1965-07-26 US US847493A patent/US3545969A/en not_active Expired - Lifetime
  • 1965-07-26 US US474977A patent/US3512966A/en not_active Expired - Lifetime
• 1966
  • 1966-07-07 FR FR7945A patent/FR1488489A/fr not_active Expired
  • 1966-07-07 FR FR7946A patent/FR1487052A/fr not_active Expired
  • 1966-07-21 GB GB32707/66A patent/GB1092618A/en not_active Expired
  • 1966-07-25 DE DE1966J0031397 patent/DE1522644B2/de active Granted

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