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
  • G03G5/0609—Acyclic or carbocyclic compounds containing oxygen

Definitions

• the present invention relates to an electrophotographic material comprising a conductive carrier and a photoconductive insulating layer applied thereto, the latter comprising metal resinates or such compounds in combination with additives.
• metal resinates as used herein means salt-like compounds of metals and resin acids.
• the electrophotographic process comprises electrostatically charging, in the absence of actinic light, a photoconductive insulating layer comprising a photoconductor compound and then exposing the charged area to light under a master, whereby the charge leaks away in the exposed areas.
• the latent electrostatic image thus obtained is made visible by treatment .with a toner and, if necessary, fixed.
• Photoconductive insulating layers have been proposed containing inorganic or low molecular weight organic photoconductor materials.
• Such materials include e.g. sulfur, zinc oxide, anthracene, anthraquinone, oxazoles ortriphenylmethane. If these photoconductors are used, they must be applied to the carrier in combination withbinders in order to form a layer suitable for practical purposes. If no binders are used, the photoconductor substances do not adhere at all or only insufiiciently adhere to the carrier, because of their amorphous or crystalline structure, and, because of their non-uniform distribution, non-uni! form images are obtained. Thus, these images are not very suitable for storage and for reproduction. purposes.
• high molecular weightv compounds e.g. polyacrylic acid and its derivatives
• these high molecular weight compounds cannot be used for reproduction with certain restrictions only. They have an adverse influence on the image production because of their tendency to turn yellow and form a nonuniform undulating surface.
• the number of solvents therefor is very limited so that difiiculties are encountered in producing the coating solution. Further, their photoconductor properties are not entirely satisfactory.
• the electrophotographic material of the present invention enables a homogeneous photoconductor layer comprising a uniform chemical substance of resinous character to be used for reproduction purposes.
• the carrier advantageously can be coated with the layer in one coating step without previous mechanical mixing of the various ingredients.
• the metalresinates which are used in the present invention are readily soluble in all conventional solvents so that the selection and concentration of the solvents used for the production of the coating solution may be widely varied.
• the surface of the photoconductive layer is smooth and does not show any disturbing tendency to turn yellow, which impairs the usefulness of the layer Due to theuniform structure of the layer, an equal and uniform photoconductivity is elfected at all points of the layer, whereby an excellent image with high marginal sharpness isobtained.
• the material of the present invention preferably is used for the production of printing cadmium, chromium,
• the photoconductive compounds give excellent re-- sults also in combination with resinous binders, since they comprise an inorganic and an organic component.
• metal resinates used in the present invention means salt-like compounds of metals and resin acids. Such compounds sometimes are called resin soaps or resin acid salts.
• the resinates are known. They can be obtained e.g. by reacting metal salts with resin acids in solvents, if necessary while heating, or by melting the two components together. Generally, these compounds are not uniform as they are commercially produced and used. However, it is possible to obtain well defined compounds by using stoichiometric quantities of the stated reaction components. Both types of compounds may be used in the present invention. Methods for the production thereof are described e.g. in Kunststoff, Lack-und Kunststoff Anlagen analyses by D. Hummel, Carl Hauser-Verlag, Kunststoff (1958), page 119 et seq. The literature cited further describes a method for the production of metal resinates by melting metal oxides and metal hydroxides together with resin acids.
• resin acid components as used in the present case is meant to include e.g. low molecular weight products which may be isolated from vegetable resins ac cording to known procedures. Resins with an extraordinarily high acid content are found in the secretions of conifers, e.g. pines and firs. These natural resin acids are mostly mixtures of isomeric monocarboxylic acids in the case of conifers, e.g. pimaric acid or abietic acid having the formula 0 1-1 0 Other Well known resins which may be used with advantage in the present invention are e.g.
• aromatic acids which are found in the copal resins, such as agathenediocic acid C H O illuric acid C H O podocarpic acid C17H2203, fusion point 188 C., elemic acid C H O sumaresinolicacid C H O and siaresinolic-acid C30H4g04. Generally, these acids have melting points between 130 and 300 C. Some of themmay be easily separated. As far as their chemical constitution is known, the resin acids may also be synthetically produced.
• Metallic compounds e.g. metal salts or metal oxides which may be used in the present case for the production of metal resinates, are derivatives of metals of the entire Periodic System, e.g.- sodium, potassium, magnesium, calcium, strontium, barium, aluminum, tin, lead, antimony, bismuth, iron, cerium, cobalt, nickel, copper, silver, zinc,
• molybdenum molybdenum, manganese or mixtures of such metals.
• a bromic acid, hydrofluoric acid, hydroboric acid or the sulfuric or phosphoric acids are listed in LackrohstolT-Tabellen by Karsten, 2nd edition, Curt R. Vincentz Verlag, Hannover (1959), pages 27, 28, 217 and 218.
• Zinc resinates containing 4 to 8 percent by weight of zinc and, cium are Zinc resinates containing 4 to 8 percent by weight of zinc and, cium.
• a material of this kind is, e.g. Erkazit Hartharz 44, having a melting point between 130 and 150 C., a calculated acid number of 30 and a color value of 8.5 to 9.5.
• Other suitable compounds are, e.g. Erkazit Magnesium- Hartharz V 112, having a melting point of 120 to 140 C.
• metal resinates such as cerium resinate containing 8 percent cerium and ob'tained'from a mixture of resin acids isolated from copal resin; as well as metal resinates with this resin acid mixture which contain 33 percent by weight if desired, about 4 to 10 percent by weight of cal-,
• additives are e.g. inorganic and organic photoconductors, sensitizers, activators, pigments, film-forming substances, and stabilizers.
• Photoconductors which may be added to the layers of the invention are inorganic and organic photoconductive substances. Good results are obtained if photoconductive zinc oxide and organic compounds such as oxadiazoles, imidazoles, triazoles, oxazoles, thiazoles, and imidazolones are added.
• sensitizers By the addition of sensitizers, the spectral sensitivity of the photoconductive layers may be shifted further into the visible range so that the exposure times may be shortened while good results are still obtained. Small additions such as 0.001 percent by weight have shown good effects.
• sensitizers most of which are dyestuffs, are described e.g. in Belgian Patent No. 558,078.
• Suitable pigments which, if desired, may be added in minor amounts to obtain special layer effects are titanium dioxide, aluminum oxide and non-photoconductive zinc oxide.
• film-forming substances may be resins such as: balsam resin, colophony, shellac, and synthetic resins, such as phenolic resins modified with colophony, and other resins with a higher proportion of colophony, coumarone resins, in dene resins and the resins within the collective term of lacquer resins.
• these lacquer resins include modified natural substances such as cellulose ethers, polymers such as vinyl polymers, e.g.
• polyvinyl chloride polyvinylidene chloide, polyvinyl acetate, polyvinyl acetals, polyvinyl ether, copolymers of vinyl chloride, vinyl acetate, and maleic acid, polyacrylic ester, polymethacrylic ester, polystyrene and copolymers, e.g. of styrene and maleic anhydride, polycondensates, e.g.
• polyesters such as phthalate resins, terephthalic acid and isophthalic acid-ethyleneglycolpolyester, maleinate resins, maleic acid/colophony/mixed esters of higher alcohols, phenolformaldehyde resins, particularly condensates of phenol and formaldehyde modified with colophony, urea-formaldehyde resin, condensates of melamine and formaldehyde, aldehyde resins, ketone resins, xylene-formaldehyde resins, polyamides, polyurethanes, and polyolefins such as low molecular weight polyethylene, polypropylene, polyisobutylene, and chlorinated rubber may also be used for this purpose.
• phenolformaldehyde resins particularly condensates of phenol and formaldehyde modified with colophony
• urea-formaldehyde resin condensates of melamine and formaldehyde
• the ratio of resin to photoconductor may vary within a wide range. Mixtures of 2 parts by weight of resin and 1 part by weight of photoconductor to mixtures containing 2 parts by weight of photoconductor per part by weight of resin are preferred.
• Stabilizers which may be added are e.g. zinc chloride, naphthalene-1,3,6-trisulfonic acid or other compounds conventionally used for this purpose.
• the overall quantity of the additives to be added should be kept low, e.g. normally at a maximum of 40 percent by weight, however, a few percent will be enough for special purposes.
• a carrier for the photoconductive layers of metal resinates there may be used all suitable supports known for this purpose, particularly metal and paper. If paper is used as a carrier, it preferably should be pretreated to prevent the penetration of the coating solution. Foils provided with a metal layer, e.g. of aluminum, by lamination or vacuum-deposition are well suited for this purpose.
• the metal resinates are preferably dissolved in organic solvents such as benzene, acetone, methylene chloride, ethylene glycolmonomethylether or mixtures thereof and the carrier is coated in a conventional manner, e.g'. by dipping, spraying, brushing or roller application. The layer is then dried whereupon a uniform, homogeneous, transparent, mostly uncolored photoelectrically conductive layer is obtained.
• organic solvents such as benzene, acetone, methylene chloride, ethylene glycolmonomethylether or mixtures thereof
• the carrier is coated in a conventional manner, e.g'. by dipping, spraying, brushing or roller application.
• the layer is then dried whereupon a uniform, homogeneous, transparent, mostly uncolored photoelectrically conductive layer is obtained.
• the photoelectrically conductive insulating layer of the invention is charged, e.g. by a corona discharge from a charging device maintained at 6,000 to 7,000 volts. Then, the electrophotographic copying material is exposed under a master, or by episcopic or diascopic projection of a master, so that an electrostatic image corresponding to the master is obtained.
• This invisible image is developed by contacting it in known manner with a developer comprising a carrier and a toner.
• the developer may also comprise a resin or a pigment which is suspended in a dielectric liquid. The image made visible in this way is fixed, e.g.
• a particularly preferred field of application of the material of the present invention is in the printing art, by transforming the images obtained by electrophotographic methods and, after fixing, into printing plates.
• the excellent solubility of the metal resinates in numerous solvents is of advantage since a particularly easy and thorough decoating of the non-printing areas is facilitated.
• the metal resinates have an excellent adhesion to metallic supports which particularly increases the resistance to abrasion of the printing plate during the printing process. Thus longer runs with uniform quality are obtained.
• Such a transformation of a fixed electrophotographic image may be effected by rubbing the carrier material, e.g. paper or metal, with a solvent for the photoelectrically conductive layer, e.g. with alcohol, acetic acid or caustic soda solution, then rinsing with water and contacting it in known manner with greasy ink.
• a solvent for the photoelectrically conductive layer e.g. with alcohol, acetic acid or caustic soda solution
• the electrophotographic images may also be used as masters for producing further copies on any light-sensitive layer. Further, images may be produced by the reflex process if transparent carrier substances are used for the photoconductive layers of the present invention.
• the electrophotographic material has the advantage that it may be charged positively as well as negatively, so that by merely reversing the poles, positive images may be obtained from negative as well as from positive masters, with the same developer.
• the layer is charged negatively and exposed under a positive master, positive images are obtained if a developer is used containing a positively charged toner.
• the positively charged toner is deposited in the unexposed, negatively charged areas.
• positive copies may be obtained under the same conditions from negative masters.
• the positive toner in this case is repelled by the unexposed positively charged areas and is deposited in the exposed, discharged areas.
• Example 1 2 parts by weight of zinc resinate, i.e. Erkazit Zinkharz 165, having a fusion point between 150 and 170 C., are dissolved in 30 parts by weight of toluene, and 0.004 part by weight of crystal violet, dissolved in 0.5 part by volume of methanol, is added.
• the solution is applied to paper, the surface of which was pretreated to prevent the penetration of organic solvents, and then dried.
• the paper coated in this way is negatively charged by means of a corona discharge, exposed under a positive master with a 500 watt bulb, and contacted in known manner with a developer comprising a carrier and a toner.
• Suitable carriers are tiny glass balls, iron powder, and other inorganic materials.
• the toner comprises a mixture of a resin and carbon black or colored resins having an average particle size of l to 100/l.- An image corresponding to the master is obtained which is fixed by slight heating and shows excellent contrast effect.
• Example 2 1 part by weight of a lead resinate, i.e. Bleiresinat No. 152, which has a lead content of 28.6 percent by weight, 0.05 part by weight of chloranil, and 0.005 part by weight of brilliant green are dissolved in 15 parts by volume of chloroform, and the solution is applied to aluminumlaminated paper. After evaporation of the solvent, a layer remains which --firmly adheres to the aluminum surface. After negative charging by means of a corona discharge, the paper is exposed for one minute under a positive master, using a 500 watt bulb at a distance of 30 cm. Then, a developer powder as employed in Example 1 is applied. An image corresponding to the master is obtained which is fixed by means of trichloroethylene vapors.
• a lead resinate i.e. Bleiresinat No. 152
• chloranil 0.05 part by weight of chloranil
• 0.005 part by weight of brilliant green are dissolved in 15 parts by volume of chloroform, and the solution is
• Example 3 In 100 parts by volume of ethyleneglycol monomethylother there are dissolved parts by weight of an iron resinate, i.e. a mixture of 90 percent by weight of an iron salt of abietic acid and 10 percent by Weight of an iron salt of pimaric acid, 2 parts by weight of ethylpropylaminobenzoic acid and 0.01 part by weight of Rhodamine B extra, and the solution is applied to a mechanically roughened, brushed aluminum foil, the brushing effect having a mean depth of 4 to 5;. After evaporation of the solvent, a layer with a thickness of 4a remains which adheres firmly to the surface of the foil.
• an iron resinate i.e. a mixture of 90 percent by weight of an iron salt of abietic acid and 10 percent by Weight of an iron salt of pimaric acid
• Rhodamine B extra 2 parts by weight of ethylpropylaminobenzoic acid and 0.01 part by weight of Rhodamine B extra
• the electrocopying material thus obtained is negatively charged by a corona discharge and then exposed in the cassette of a reproduction camera.
• a book page printed on both sides serves as the master.
• the layers allow a uniform development of surfaces of size DIN A 4 by means of a developer powder without using magnetic brushes.
• developer powder there may be used e.g., a toner mixture consisting of kieselguhr and a toner comprising a low melting point mixture of polystyrene and colo phony to which carbon black is added and desirably also spirit-soluble Nigrosin as an organic dyestuff.
• a toner mixture consisting of kieselguhr and a toner comprising a low melting point mixture of polystyrene and colo phony to which carbon black is added and desirably also spirit-soluble Nigrosin as an organic dyestuff.
• the components of the toner are melted together, subsequently milled, and air sifted since a uni-form grain size is preferable for the production of images.
• a fraction containing a toner with grain sizes from 5" to 101w is very suitable.
• a toner with a grain size from 0.5 to 2 is best employed.
• the image is fixed by heating to 150 to 170 C. for 30 seconds.
• the electrophotographic image thus obtained may be transformed to a printing plate by swabbing it with a solution containing 40 percent by weight of methanol, 10 percent by weight of glycerine, 45 percent by weight of glycol, and 5 percent by weight of sodium silicate.
• the areas of the layer not covered by the toner are dissolved away and rendered hydrophilic whereas the printing or image areas accept greasy ink so that, after mounting the printing plate thus obtained in an offset machine, printing can be performed.
• Example 4 2 parts by weight of the antimony salt of dehydroabietic acid, isolated from colophony, 0.15 part by weight of dichloro-acetic acid and 0.006 part by weight of Eosin S are dissolved in 30 parts by weight of methylene chloride, and the solution is applied to a paper sheet which is impermeable to solvents. After evaporation of the solvent, the remaining layer adheres firmly to the paper surface.
• the further procedure for the preparation of an image is as described in Example 1 and, when a positive master is used, a positive image is obtained which is also fixed as in Example 1.
• Example 5 The process of Example 1 is followed with the exception that the zinc resinate is replaced by a calcium resinate, i.e. Crayvallac 571, containing 5 percent calcium. The dried layer is charged positively and exposed under a negative master. After developing and fixing according to Example 1, a positive copy is obtained.
• a calcium resinate i.e. Crayvallac 571
• Example 6 2.5 parts by weight of a cobalt resinate containing 7.3 percent by weight of cobalt, 2.5 parts by weight of a magnesium resinate, 0.3 part by weight of diethylaminobenzoic acid and 0.006 part by weight of rose bengal are dissolved in 40 parts by volume of benzene and the solution is applied to a brushed aluminum foil. After evaporation of the solvent, a layer remains which adheres firmly to the surface of the foil. Further procedure is as in Example 1 and an image corresponding to the master is obtained on the aluminum surface which, after powdering with a developer as described in Example 1, is fixed by heating.
• the aluminum foil provided with the image can be converted into a printing plate by swabbing the image side of the aluminum foil with percent alcohol, rinsing with water and rubbing with greasy ink and 1 percent phosphoric acid.
• a printingplate is obtained corresponding to the master used which, after fixing, may be used for printing.
• Example 7 25 parts by weight of zinc resinate, having a fusion point of to C., 3 parts by weight of anthraquinone and 0.01 part by weight of patent blue AE are dissolved in a mixture of 50 parts by volume of benzene and 50 parts by volume of chloroform. The resulting solution is applied to a paper sheet which is treated to prevent the penetration of solvents. Direct images are produced on the paper following the procedure described in Example 1.
• Example 8 2 parts by weight of manganese resinate, containing 3 percent by weight of manganese, 0.01 part by weight of ion-trichloride and 0.003 part by weight of methyl violet are dissolved in 20 parts by volume of trichloroethylene and the solution is applied to aluminum-laminated paper. After evaporation of the solvent, a layer remains which adheres firmly to the aluminum surface. The layer is positively charged by a corona discharge and exposed under a positive master.
• the developer used comprises a mixture of a colored resin/carbon black mixture and resin-coated glass balls. A positive copy is obtained.
• Example 9 1 part by weight of cerium resinate, containing 8 percent by weight of cerium, 1 part by weight of a cobaltbarium-Zinc resinate, and 0.2 part by weight of 1,4-toluquinone are dissolved in 30 parts by volume of toluene and 0.005 part by weight of methylene blue in 1 part by volume of methanol is added. For the remainder of the process, the procedure of Example is followed.
• An electrophotographic material comprising a conductive support having a photoconductive insulating layer thereon, the latter comprising a metal resinate.
• a photographic reproduction process which comprises exposing a supported, electrostatically charged, photoconductive insulating layerto light under a master and developing the resulting image with an electroscopic material, the photoconductive layer comprising a metal resinate.
• a process according to claim resinate is iron resinate.
• a process according to resinate is antimony resinate.
• a process according to resinate is calcium resinate.
• a process according to resinate is cobalt resinate.
• a process according to resinte is manganese resinate.
• a process according to claim resinate is cerium resinate.

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  • NL NL301475D patent/NL301475A/xx unknown
• 1962
  • 1962-12-18 DE DEK48510A patent/DE1254467B/de active Pending
• 1963
  • 1963-12-12 GB GB49178/63A patent/GB1068160A/en not_active Expired
  • 1963-12-16 US US330602A patent/US3373020A/en not_active Expired - Lifetime
  • 1963-12-16 CH CH1540563A patent/CH426491A/de unknown
  • 1963-12-16 BE BE641346A patent/BE641346A/xx unknown

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