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 or 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
• • 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
  • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
  • Y10S430/001—Electric or magnetic imagery, e.g., xerography, electrography, magnetography, etc. Process, composition, or product
  • Y10S430/10—Donor-acceptor complex photoconductor

Definitions

• the electrophotographic copy process use is made of a photoconductive surface onto which a uniform electrostatic charge is applied.
• the charge is retained on the surface except for those areas that are rendered conductive during exposure to a light pattern, leaving a latent electrostatic image on the non-exposed portions of the photoconductive surface.
• the latent electrostatic image is subsequentlydeveloped in a conventional manner, as by means of a dry developing powder which is cascaded over the surface, or by a liquid developer or toner suspended in an insulating liquid with which the plate surface is wet.
• the latent electrostatic image can be transferred to a copy sheet for development of the image thereon, as by a liquid or powder developer.
• selenium provides a photoconductive surface having the desired speed and sensitivity for use in high speed copy machines
• selenium represents a relatively expensive material which is difficult to apply, and its use as a of disadvantages in that organic photoconductors,-
• Organic photoconductors of the type described are capable of copy speeds in the range of 10 to copies per minute.
• the charge acceptance and sensitivity of organic photoconductors can be markedly increased when the organic photoconductor is formulated to contain an alicyclic anhydride.
• the improvement in charge acceptance and sensitivity, as measured by charge decay, is particularly. significant when the alicyclic anhydride is present in an organic photoconductor composition formulated of a polymerized vinyl carbazole (PVK) in 2,4,7-trinitro-9-fluorenone (TNF), to form photoconductive coatings of the charge-transfer complex types.
• PVK polymerized vinyl carbazole
• TNF 2,4,7-trinitro-9-fluorenone
• R and R can also be an anhydride functional group.
• R can be hydrogen, loweralkyl groups suchas methyl, ethyl, propyl, etc., halogen such as.chlorine, bromine, iodine, etc., hydroxy, nitrile or nitro groups.
• R can be the same or different and R and R,, as well as R and R can be an anhydride functional group.
• cyclohexanedicarboxylic anhydrides are l,2-cyclohexanedicarboxylic anhydride, and their cis and trans isomers, cis-l,2-dimethyl-l,2- cyclohexanedicarboxylic anhydride, trans-1,2-dimethyl-l ,2-cyclohexanedicarboxylic anhydride, 1,2,4,5- cyclohexanetetracarboxylic-l ,2,4,5-dianhydride, and 1,2,3 ,4,5 ,6-cyclohexanehexacarboxylic l ,2:3 ,4: ,6-trianhydride.
• Suitable alicyclic anhydrides range from anhydrides having at least 3 carbon atoms in the alicyclic group as represented by 1,2-cyclopropanedicarboxylic anhydride, to and including anhydrideS dianhydrideS and polyanhydrides havingup to 18-20 carbon atoms in'the cyclic group, although it is preferred to make use of anhydrides having substituents as described in (a), ,(b)
• polymerized vinyl carbazole compounds which may be used in the formulation of the organic photoconductive coatings of this invention, namely: poly-N-vinyl carbazole and polyvinyl-N- lower alkyl carbazoles of the type described in the US. Pat. No. 3,484,237.
• poly-N-lower alkyl carbazoles namely, poly-2-vinyl-N-methylcarbazole, poly-3-vinyl- N-ethylcarbazole, .poly-2-vinyl-N-ethylcarbazole, poly-' 3-vinyl-N-methylcarbazole, poly-3-vinyl-N-isopropylcarbazole, poly-2-vinly-N-butylcarbazole, poly-3-vinyl- N-butylcarbazole', poly-2-vinyl-N-pentylcarbazole, poly-3-vinyl-N-pentylcarbazole, poly-Z-vinyl-N-hexylcarbazole, poly-3-vinyl-N-hexylcarbazole, poly-2-vinyl- N-heptylcarbazole, and poly-3-vinyl N-hep'ty
• the ingredients are formulated into the coating composition in the ratio of about 0.49 to 1.3 moles of TNF per monomer unit of PVK, which ratio will continue in the organic photoconductor that is formed upon coating a suitable substrate and then dried to cure the coating onto the substrate.
• the substrate use can be made of a rigid plate or drum formed of glass or of a metal such as aluminum having a silicated surface and the like, or the substrate upon which the photoconductive coating is applied may be a flexible element, such as a plate, drum, or endless belt formed of paper, plastic, metal-paper laminate, or a sheet of silicated aluminum or the like.
• the materials are formulated into a composition for coating onto a suitable substrate by first dissolving the polyvinylcarbazole component in a suitable solvent, such as tetrahydrofuran, and then admixing the solution of the polyvinylcarbazole with the 2,4,7-trinitro-9- fluorenone and alicyclic anhydride, preferably in solution in the same solvent, and any additional solvent required, to achieve the desired consistency for the coating composition.
• a suitable solvent such as tetrahydrofuran
• the photoconductive compositions of the present invention are useful in the conventional xerographic process in which an electrostatic image is formed on the surface of the photoconductive element and the electrostatic image is subsequently developed.
• the photoconductive element is electrostatically charged and exposed to a pattern of light and dark to form an electrostatic image.
• the electrostatic image can either be developed with a conventional electroscopic powder developer on the photoconductive element and the developed image transferredto plain paper, or the electrostatic image can be transferred to a dielectric paper for development with an electroscopic developer (powder or liquid).
• EXAMPLE 1 In this example, comparison is made between an organic photoconductor embodying the features of this invention, with a photoconductor of identical composition except for the omission of the alicyclic acid anhydride component.
• Each segment was diluted with equal volumes of tetrahydrofuran to reduce the materials to coating viscosity. 2. ml of a 1% solution of cis-l ,2- cyclobutanedicarboxylic acid anhydride in tetrahydrofuran was added to segment l(b).
• the coating compositions were applied onto separate silicated aluminum belts having a'thickness of 3.5 mils. Coating was effected by mounting the belts on a drum operated for rotational movement about a horizontal axis. Application was made by means of an air brush mounted a fixed distance from the surface of the belt and displaced crosswise over the surface of the belt in increments of 2 mm per revolution, and operated under a pressure of 18 psi with nitrogen. An amount was applied to form a dried coating having a thickness of about -l2 microns.
• the coated plates were allowed to air dry and then they were cured for 1 hour at 50C.
• the plates were each tested for charge acceptance and charge retention by exposing the plates to negative electrostatic corona charge of 6 kv by passing the plates beneath charging wires.
• Charge acceptance and charge retention were measured by a Monroe electrometer which measures the charge on the surfaces of the plates in volts.
• the plates were also each tested for sensitivity by the use of the Monroe electrometer to measure the amount of charge dissipated by light exposure.
• exposure was made with a tungsten photoenlarger lamp of 150 watts operating through an enlarger. Energy of exposure identifies the amount of light that fell on the plate in pJlcm as measured by a Hewlett-Packard radiant flux meter.
• the amount of conductive coating applied to the substrate is not significant.
• the desired results can be obtained in coating weights sufficient to provide coating thickness of 5 microns; however, it is undesirable from the standpoint of economics and flexibility of the coating to exceed a coating thickness of about 30 microns.
• carboxylic acid anhydride and carboxylic anhydride are used by the skilled in the art and in this application to identify the same compound.
• an electrophotographic element for use in an electrophotographic copy process formed of a substrate having an organic photoconductive coating formed of 2,4,7-trinitro-9-fluorenone and a polymerized vinyl carbazole present in the ratio of 0.49 to 1.23 moles of the trinitro fluorenone per monomeric unit of polymerized vinyl carbazole on one surface, the improvement wherein an alicyclic anhydride is incorporated into the organic photoconductive composition whereby the charge retention and sensitivity of the photoconductive coating is markedly improved to increase copy speed.
• An electrophotographic element as claimed in claim 1 in which the alicyclic anhydride is present in the coating in an amount within the range of 0.01% to 1.0% by weight of the coating solids.
• An electrophotographic element as claimed in claim 1 in which the alicyclic anhydride is present in the coating in an amount within the range of 0.02% to 0.5% by weight of the coating solids.
• An electrophotographic element as claimed in claim 1 in which the cyclic group of the alicyclic anhydride is selected from the group consisting of cyclobutane, cyclopentane and cyclohexane, and substituents thereof.
• An organic photoconductive composition for use in the preparation of a photoconductive coating from which copies can be produced by an electrophotographic process in which the composition consists essentially of an organic photoconductor and 0.1% to 1.0% by weight (based on coating solids) of an alicyclic anhydride having from 3 to 20 carbon atoms in the alicyclic group.
• a composition as claimed in claim 8 in which the organic photoconductor comprises 2,4,7-trinitro-9- fluorenone and a polymerized vinyl carbazole present in the ratio of about 0.49 to 1.23 moles of the trinitro fluorenone per monomeric unit of the polymerized vinyl carbazole and in which the materials are present in solution in an organic'solvent.
• composition as claimed in claim 9 in which the alicyclic anhydride is present in an amount within the range of 0.02% to 0.5% by weight of the coated solids.
• a composition as claimed in claim 9 in which the organic solvent in which the photoconductive materials are dissolved is tetrahydrofuran.
• composition as claimed in claim 8 in which the alicyclic group of the alicyclic anhydride is selected from the group consisting of cyclobutane, cyclopentane and cyclohexane, and derivatives thereof.

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• Health & Medical Sciences (AREA)
• Emergency Medicine (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Photoreceptors In Electrophotography (AREA)

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Citations (4)

• 1974
  • 1974-08-28 US US501132A patent/US3929478A/en not_active Expired - Lifetime
• 1975
  • 1975-08-15 CA CA233,538A patent/CA1068970A/fr not_active Expired
  • 1975-08-25 DE DE19752537770 patent/DE2537770A1/de not_active Withdrawn
  • 1975-08-27 GB GB35420/75A patent/GB1479399A/en not_active Expired
  • 1975-08-28 JP JP50103551A patent/JPS5177240A/ja active Pending

Patent Citations (4)

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