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
  • G03G5/07—Polymeric photoconductive materials
  • G03G5/075—Polymeric photoconductive materials obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• • 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

Definitions

• Electrophotographic materials consisting of a support and a photoconductive layer which contains an inorganic substance as a photoconductor e.g. selenium, zinc oxide or an organic substance such as anthracene, benzidine or a heterocyclic compound.
• photoconductive polymers are employed in the manufacture of photoconductive layers such as described in the Belgian patent specifications 588,048, 588,049, 588,050, 599,627 and 604,127.
• Homogeneously covered image areas may also be obtained e.g. by charging the electrophotographic material through an intermittent contact with macromolecular substances instead of charging the electrophotographic material by an ionisation effect in an air layer, as occurs in the corona discharge. This method is described in the Belgian patent specification 568,659.
• a specific composition of the photoconductive layer is used, containing besides the photoconductive component: zinc oxide, other organic or mineral substances with a grain size and in a weight ratio based upon that of the photoconductor. This process is described in Belgian patent specification 576,367.
• an electrophot-ographic material comprising a photoconductive layer containing two different high-molecular compounds, one of which being discontinuously present in the other, which in its turn is present in the layer in a continuous way and which consists of a photoconductive polymer, the product of the dielectric constant e and the specific resistivity p of said photoconductive polymer being at least two times greater or smaller than the product of the dielectric constant e and the specific resistivity p of the high-molecular compound which is discontinuously present in the photoconductive layer, the quality of the formed image and especially the uniformity of the image and the density of the black par-ts are markedly improved.
• the determination of the resistivity in the dark of photoconductive polymers is carried out according to Standard Method of Test for Electrical Resistance of Insulating Materials, A.S.T.M. designations: D 257-58 ((41) Volume Resistivity), p. 612, and also D 1371-55 T, p.
• POLYSACCHARIDES AND PROTEINS Polyethylene, polytetrafiuoroethylene, polyamides of the adipic acid-hexamethylene diamine type, polyamides of the caprolactam type, rubber, phenol-formaldehyde resins, and urea-formaldehyde resins.
• Aluminum polysilicates e.g. porcelain powder and kaolin.
• Polymeric compounds which are used as additives for the elimination of the fringing effect areinsoluble or are made insoluble in the usual solvents. This insol'ubiliz'ation can take place during the polycondensation if a synthetic product is concerned e.g. by cross-linking or hardening, or by an after-treatment after the formation of the polymer, e.g. photopolymerization, heat treatment, chemical hardening or vulcanization.
• the size of the particles of the added macromolecular compounds preferably varies between 1 and a.
• the particles can occur in the form of grains, fibres or scales, without excluding, however, other particle forms.
• the solvent is chosen in such a way, that the particles to be dispersed of the high-molecular compound remain in their undissolved state whereas the photoconductive polymer can dissolve.
• the obtained dispersion is uniformly spread over the surface of a support e.g. by centrifugation, spraying, brushing or coating, whereupon the formed layer is dried in such a way, that a uniform photoconductive layer is obtained.
• the amount of macromolecular dispersed particles amounts to 5 to 50% based on the weight of the photoconductor.
• the thickness of the photoconductive layers is not critical, but is open to choice within a wider range according to requirements. Good results are obtained with photoconductive layers having a thickness of between 1 and 20 but preferably of between 3 and 10;. Layers which are too thin have an insuificiently insulating power and layers which are too thick require extensive exposure times.
• dispersions of the above mentioned macromolecular compounds in solutions of previously polymerized compounds, but that e.g. dispersions in mixtures of monomeric and polymeric substances can be applied onto the surface of the support to be coated, and that these may be polymerized in situ, condensed or cross-linked according to one of the known methods in polymer chemistry.
• the photoconductiv'e layers manufactured according to this invention may still contain one or more photoconductive monomeric compounds.
• monomeric photo'conductors are considered e.g. the photoconductive compounds mentioned in the U.S. patent specifications 2,599,542 (anthracine) and 2,663,636 (anthraquinone, acenaphthene, fluoranthene, naphthalene, chrysoquinone, pyrogallic acid and microcrystalline Waxes), the French patent specification 1,176,381 and the published German patent specification 1,060,712, the Belgian patent specifications 558,078, 558,630, 562,336, 562,426, 563,045 and 570,790, and the Austrian patent specification 205,516 (p-diphenyl benzene, benzanthrone and aromatic nitriles).
• a binding agent may be added for obtaining a mechanically suificiently strong subbing layer, such as described in the Belgian patent specification 585,555. If desired, plasticizers may be added which are also described in that same patent specification.
• the photoconductive layers according to this invention there can further be present compounds which occasionally possess photoconductive properties and which cause an increase of the general sensitivity and/ or of the sensitivity for electromagnetic rays from a defined part of the spectrum.
• compounds which occasionally possess photoconductive properties and which cause an increase of the general sensitivity and/ or of the sensitivity for electromagnetic rays from a defined part of the spectrum.
• Such compounds are described for instance in Belgium patent specification 588,050, p. 12-22, classes A to T inclusive. These compounds are pref- 'er'ably employed in amounts ranging from 0.1 to 5% based upon the weight of the used polymeric photo'conductive substances.
• additives well known in the art of coating, which may be used, include agents controlling ageing, oxidation, gloss, thermal stability, electric conductivity, mechanical resistance, viscosity or other physical properties. In selecting such additives, preference is given to those substances which do not markedly decrease the dark-resistivity of the photoconductive layer.
• this new invention should by no means be limited to one or other special embodiment, in regard to the use of the new electrophotographic materials, the method of charging, the exposure technique, the transfer (if any), the developing method, and the fixing method as well as the materials used in these steps can be chosen according to requirements.
• Electrophotographic materials according to the present invention can be applied in reproducing techniques using different kinds of radiations, not only electromagnetic radiations as hereinbefore referred to but also nuclear radiations. For this reason, it should be pointed out that although materials according to the invention are mainly intended for application in processes involving an exposure, the term electrophotograp-hy wherever appearing in the description and the claims is used broadly, and includes both xerogra-phy and xeroradiography.
• EXAMPLE 1 A baryta-coated paper of 90 g./sq. m. bearing g. of baryta per sq. m., is coated with a layer from a 12% solution of Hostalit CAM (trademark of Farbwerke Hoechst A.G., Frankfurt am main-Hochst for a ter polymer of vinyl chloride, vinyl acetate and maleic anhydride) in acetone. The thickness of the dried layer is 5 This support is then coated with a layer from the following composition:
• this material is negatively charged with a corona device.
• This material is exposed for 20 sec. through a diapositlve with a 100 Watt lamp placed at a distance of 10 cm.
• the latent electrophotographic image is then developed with a mixture consisting of 5 g. of Graph-O-Fax Toner No. 3 (trade-name of Philip A. Hunt Company, Palisades Park, N.J., for a xerographic developing dyestufi?) as a toner, and 100 g. of iron powder as a carrier.
• EXAMPLE 2 A mixture of the following composition is ground for 12 h. in a ball-mill:
• Copolymer of vinylcarbazole and ethyl acrylate prepared according to the method described in Belgian patent specification 589,995) g 7.5 Basic blue 3 (Cl. 51,005) mg 4 Starch-N-phenyl carbamate (prepared according to preparation 2) g 1 Methylene chloride cm 100
• this photoconductive layer amounts to 10
• the material is then charged with a corona device and exposed in an enlarger with a lamp of 75 watts. A linear enlargement of 10 times of a dia positive requires an exposure of 2 min.
• the obtained material is developed with a tribo-electric powder as described in Example 1. A vigorous image is obtained having a clear background and well covered black parts.
• electrophotographic material is subjected to a substantially uniform electrical field to produce electrostatic charge completely thereover and is thereafter exposed to said electromagnetic radiation image to create said pattern of electrostatic charges.
• An electrophotographic material for use in the method of claim 1 comprising a supported layer comprised essentially of a continuous phase of an insulating organic polymer becoming conductive upon exposure to electromagnetic radiation, said polymer phase having at least substantially uniformly distributed therethrough a separate dispersed phase of discrete finely divided particles of a polymeric substance less conductive upon exposure to said radiation than said insulating organic polymer, the arithmetic product of the dielectric constant and the specific electric resistance of said insulating polymer measured in the dark differing by a factor of at least two from that of said polymeric substance, the amount of said polymeric substance in said layer being about 550% by weight of said insulating organic polymer.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Photoreceptors In Electrophotography (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Cited By (14)

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Citations (3)

• 1960
  • 1960-10-12 NL NL256772D patent/NL256772A/nl unknown
• 1961
  • 1961-10-11 DE DEG33302A patent/DE1215523B/de active Pending
  • 1961-10-12 BE BE609056D patent/BE609056A/nl unknown
  • 1961-10-12 FR FR875755A patent/FR1314416A/fr not_active Expired
  • 1961-10-12 GB GB36700/61A patent/GB1007349A/en not_active Expired
  • 1961-10-12 US US144579A patent/US3281240A/en not_active Expired - Lifetime

Patent Citations (3)

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