US3552959A - Electrophotographic copying paper - Google Patents

Electrophotographic copying paper Download PDF

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Publication number
US3552959A
US3552959A US713893A US3552959DA US3552959A US 3552959 A US3552959 A US 3552959A US 713893 A US713893 A US 713893A US 3552959D A US3552959D A US 3552959DA US 3552959 A US3552959 A US 3552959A
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Prior art keywords
acid
nitrate
photoconductive
organic
electrophotographic copying
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Expired - Lifetime
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US713893A
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English (en)
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Nario Yamaguchi
Kazuo Tubuko
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Ricoh Co Ltd
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Ricoh Co Ltd
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    • 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
    • G03G5/09—Sensitisors or activators, e.g. dyestuffs

Definitions

  • An electrophotographic copying paper comprising a support paper and a photoconductive layer (which is a light-sensitive layer) coated on one surface of said support and containing an organic photoconductive material, wherein said photoconductive layer further contains a metal nitrate, With or without an organic acid.
  • the present invention is concerned with a novel electrophotographic copying paper having a highly increased sensitivity to light and having a photoconductive layer which is formed with an organic photoconductive material, wherein said photoconductive layer further contains a specific assistant sensitizer.
  • an assistant sensitizer which includes: metal halides such as zinc chloride, stannous chloride, aluminum chloride, ferric chloride and stannic chloride; acids such as acetic acid, monochloro acetic acid, dichloro acetic acid and trichloro acetic acid or their anhydrides; quinones such as benzoquinone; aldehydes; and ketones.
  • these additives even decreased the sensitivity to light of such photoconductive layers, depending on the type of the sensitizing dyestuffs which were included, together with said additives, in the photoconductive layers.
  • zinc chloride or ferric chloride was included in the photoconductive layer, such a photoconductive layer exhibited a difliculty in the electrostatic charging thereof and required a relatively long period of time till the potential of the layer was saturated.
  • the inclusion of such an additive as dichloro acetic acid or trichloro acetic acid in the photoconductive layers often caused a reduction in the resistance of the photoconductive layers to light-fatigue.
  • a metal halide such as ferric chloride or stannic chloride in the photoconductive layer caused an intensive gelation of the solution for use in forming photoconductive layers, making the procedure of applying the solution onto a support such as paper difficult.
  • an electrophotographic copying material having a photoconductive layer formed on one surface thereof, said layer containing, in combination with an organic photoconductive material which is the principal component thereof, an assistant sensitiver which consists of a metal nitrate and which is capable of markedly improving the sensitivity to light of said photoconductive layer, Without adversely affecting the electrostatic property of this layer, that is to say, without in any way deteriorating the charge characteristics of the photoconductive layer or without reducing the resistance of the photoconductive layer to light-fatigue (in this latter case, the charge characteristic of the photoconductive layer is deteriorated also).
  • the metal nitrates which can be employed in the present invention are comprised of those metals which are contained in the Group I, Group II, Group III and Group VIII of the periodic table.
  • the assistant sensitizers which are particularly suitable for the objects of the present invention are those metal nitrates such as magnesium nitrate, zinc nitrate, sodium nitrate, potassium nitrate, cuprous nitrate, ferrous nitrate, ferric nitrate, cobalt nitrate, nickel nitrate, aluminum nitrate and manganese nitrate.
  • the present invention contemplates the complete elimination of the aforesaid drawbacks and inconveniences which have been encountered in the conventional electrophotographic copying papers, by the inclusion-in the photoconductive layer-of such an assistant sensitizer as enumerated above in an amount ranging from 0.1% to 15% by weight of the organic photoconductive material which is contained in the photoconductive layer.
  • the present invention also contemplates the provision of an electrophotographic copying paper whose photoconductive layer further containsin addition to the aforesaid metal nitrate--an organic acid such as organic carboxylic acids, organic sulphonic acids, organic phosphoric acids, nitrophenols and acid anhydrides in an amount ranging from 5% to 50% by weight of the metal nitrate which is contained in the photoconductive layer.
  • an organic acid such as organic carboxylic acids, organic sulphonic acids, organic phosphoric acids, nitrophenols and acid anhydrides in an amount ranging from 5% to 50% by weight of the metal nitrate which is contained in the photoconductive layer.
  • the aforesaid organic acid which can be used in the present invention includes:
  • Organic carboxylic acids such as acetic acid and the substitution products thereof, monochloro-acetic acid, dichloroacetic acid, trichloroacetic acid, phenylacetic acid, and 6-methylcoumarinylacetic acid (4); maleic acid; cinnamic acid, benzoic acid, 1-(4-diethylamino-benzoyl)- benzene-Z-carboxylic acid, phthalic acid, and tetrachlorophthalic acid, a, ⁇ 3-dibromo-fi-formyl-acrylic acid (mucobromic acid), dibromo-maleic acid, Z-bromo-benzoic acid, gallic acid, 3-nitro-2-hydroxy 1 benzoic acid, 2-nitrophenoxyacetic acid, Z-nitro-benzoic acid, 3-nitrobenzoic acid, 4-nitro-benzoic acid, 3-nitro-4-ethoxy-benzoic acid, 2-chloro-4-nitro-1benzoic acid, 3 nitro-4-me
  • Organic sulphonic acids such as 4-toluenesulphonic acid, and benzene sulphonic acid, 2,4-dinitro-1-methylbenzene-6-sulphonic acid, 2,6-dinitro-l-hydroxy-benzene- 4-sulphonic acid, 2-nitro-1-hydroxy-benzene-4-sulphonic acid, -4-nitro-1-hydroxy-benzene-Z-sulphonic acid, 3-nitro- 2-methyl-l-hydroxy-benzene 5 sulfonic acid, 6-nitro-4- methyl-1-hydroxy-benzene 2 sulfonic acid, 4-chl0ro-lhydroxy-benzene-3-sulfonic acid, 2-chloro3-nitro-1-methylbenzene-S-sulfonic acid, 2-chloro 1 methylbenzene-4- sulfonic acid;
  • Organic phosphonic acids such as 4-chloro-3-nitrobenzene-phosphonic acid
  • 'Nitrophenols such as 4-nitrophenol, and picric acid
  • Acid anhydrides for example; acetic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, tetra chlorophthalic anhydride, and chrysene 2,3-8-9- tetra-carboxylic anhydride, dibromo maleic acid anhydride.
  • An organic photoconductive material is dissolved in a solvent such as monochloro benzene, dimethyl formamide and methylene chloride in such a way that the concentration of the organic photoconductive material in the solvent is in the range of from 5% to 10% by weight of said solvent.
  • a sensitizing dyestu1Tin the form of, for example, a methanol solution-- in an amount, in terms of the dyestuff, ranging from 0.1% to 2% by weight of the photoconductive material used.
  • a metal nitrate such as those described above is added-in the form of a methanol solution, for example-to the resulting solution in an amount ranging from 0.1% to by Weight of said photoconductive material.
  • the addition, if desired to do so, of the aforesaid organic acid is performed at the time when the aforesaid metal nitrate is introduced into the solution.
  • the mixed liquid is applied onto one surface of a support such as a sheet of paper, metal plate, a film made with either a synthetic resin or a naturally occurring resinwhich has been already given an electroconducting treatment.
  • the coated support paper is then dried at a temperature ranging from 100 C. to 150 C. for a period of time ranging from 2 to 5 minutes to regulate the moisture content thereof to a level ranging from 4.0% to 4.5% by weight of the support.
  • a support such as a sheet of paper, metal plate, a film made with either a synthetic resin or a naturally occurring resinwhich has been already given an electroconducting treatment.
  • the coated support paper is then dried at a temperature ranging from 100 C. to 150 C. for a period of time ranging from 2 to 5 minutes to regulate the moisture content thereof to a level ranging from 4.0% to 4.
  • the organic photoconductive materials which can be used in the present invention include poly-N-vinyl carbazole, poly-N-dimethyl-amino-acenaphthy1ene, poly-N- vinyl-nitro carbazole, polyvinyl naphthalene, polyvinyl- N-dimethyl-amino carbazole, poly-N-diethyl-amino-acenaphthylene, polyvinyl anthracene and polyvinyl nitronaphthalene.
  • the present invention is featured in that those organic photoconductive materials of both the electron donating type and the electron attracting type can be employed equally.
  • the sensitizing dyestuffs substantially all of those basic dyes such as Rhodamine B (C.I.
  • Rhodamine G C.I. No. 45150
  • Rhodamine S C.I. No. 45050
  • Methyl Violet C.I. No. 42535
  • Ethyl Violet C.I. No. 42600
  • Crystal Violet C.I. No. 42555
  • Methylene Blue FZ C.I. No. 52015
  • Methylene Blue BI-I C.I. No. 52015
  • Victoria Blue B C.I. No. 44045
  • Brilliant Green GX C.I. No. 42040
  • Malachite Green C.I. No. 42000
  • Basic Flavine 8G C.I. No. 75670
  • Concentrated Auramine G C.I. No.
  • the presence of a metal nitrate in the photoconductive layer increases greatly the light-sensitivity of the manufactured copying papers as compared with the light-sensitivity of the conventional electrophotographic copying papers, it is to be noted that the inclusionin combinationof an organic acid and a metal nitrate in the photoconductive layers will further enhance the light-sensitivity of the copying papers produced.
  • the present invention provides an electrophotographic copying paper having a highly increased sensitivity to light, by the inclusion of a metal nitrate in the photoconductive layer which is prepared by the use of an organic photoconductive material. Also, the present invention contemplates a further increasing of the light-sensitivity of the photoconductive layer which is formed with an organic photoconductive material, by the joint inclusion of a metal nitrate and an organic acid such as formic acid or acetic acid in the photoconductive layer.
  • the accompanying drawing shows the curve which represents the electrostatic characteristics of the electrophotographic copying paper obtained in the following Example 1.
  • the solid line in the drawing denotes the characteristic curve of the electrophotographic copying paper of the present invention, while the broken line represents that of the control copying paper which is used for the purpose of the comparison of the electrostatic characteristics of these two copying papers.
  • these two curves both show the changes in the potential of the photoconductive layers which occurred during the period from the time when the copying papers were charged on, that is to say, when the photoconductive layers were impressed with an electric charge by corona discharge, with the subsequent charge off or the cessation of the charging and then leaving the copying papers in darkness for a While, to the time of the exposure of these copying papers to light.
  • Example 1 5 gr. of poly-N-vinyl carbazole was dissolved in gr. of monochloro benzene. To this solution was added 1.4 gr. of Rhodamine B 1% methanol solution) to serve as the sensitizing dyestuff. To the resulting mixed solution was added further 1.05 gr. of aluminum nitrate (5% methanol solution), and the resulting mixed liquid was stirred thoroughly. This mixed liquid was applied onto one surface of an art paper which had been already given an electroconducting treatment to a thickness of 4a. The coated support paper was then dried at C. for 5 minutes to regulate its moisture content to 4.0%.
  • the electrostatic characteristic of the electrophotographic copying paper thus obtained is shown by the solid line in FIG. 1.
  • the velocity of the light decay of the copying paper obtained in this example was noted to be about 10 times greater than that which was indicated by the electrostatic characteristic (refer to the broken line in the drawing) of the control copying paper whose photoconductive layer which was formed with poly-N-vinyl carbazole contained a sensitizing dyestutf which consisted of Rhodamine B alone.
  • Example 2 5 gr. of poly-N-vinyl carbazole was dissolved in 95 gr. of Methyl Cellosolve. To this solution were added 1.5 gr. (1% methanol solution) of Aizen Magenta, a product of Hodogaya Chemical Co., Ltd. and also 1.0 gr. 1% methanol solution) of Methylene Blue FZ and further 1.05 gr. (5% methanol solution) of zinc nitrate. The mixture was stirred completely. Thus, a mixed liquid was prepared. This liquid was applied, to a thickness of 3,u, onto one surface of a mat tracing paper of 60 gr./m. which had been given an electroconducting treatment, and was dried at 100 C. to regulate its moisture content. The copying paper thus obtained showed a light decay which was noted to be about 12 times greater in velocity than that of the control copying paper which was formed without the inclusion of zinc nitrate. The copying paper obtained in this example was found to be satisfactory with respect to the charge characteristic.
  • Example 3 5 gr. of poly-N-vinyl-nitro carbazole was dissolved in 95 gr. of dimethyl formamide. To this solution were added 1.0 gr. 1% methanol solution) of Crystal Violet and also 2.0 gr. (5% methanol solution) of magnesium nitrate, and the mixture was stirred thoroughly. Thus, a mixed liquid was prepared. This liquid was applied, to a thickness of 4a, onto one surface of an acetate film which had been given an electroconducting treatment, and the coated support was dried to regulate the moisture content thereof.
  • the copying paper obtained in this way showed a light decay which was noted to be about 8 times greater in velocity as compared with that of the control copying paper which contained no magnesium nitrate in the photoconductive layer.
  • the copying paper which mas obtained in this example according to the present invention gave a well-contrasted copied image.
  • Example 4 5 gr. of polyvinyl carbazole was dissolved in 95 gr. of monochloro benzene. To this solution were added 1.0 gr. (1% methanol solution) of Rhodamine B and also 1.05 gr. (5% methanol solution) of aluminum nitrate and 0.5 gr. (5% methanol solution) of acetic acid. The resulting mixed liquid was stirred at 70 C. for 5 minutes and then was cooled to room temperature. The resulting liquid was applied onto one face of an art paper to a thickness of 5a, and was dried at 120 C. for 2 minutes to regulate the moisture content 0 4.5%.
  • the copying paper hus obtained showed a light decay which was noted to be about 15 times greater in velocity than that of the control copying paper in which the sensitizing dyestufl contained in tis photoconductive layer consisted of Rhodamine B alone.
  • the copying paper also showed only a negligible amount of light-fatigue.
  • the copied image obtained from this copying paper of the instant example was a well-contrasted one.
  • electrophotographic copying papers were prepared from each combination of aluminum nitrate and an acid, i.e. benzene sulphonic acid, 4-chloro-3-nitro-benzene-phosphoric acid, picric acid and dibromo maleic acid anhydride, respectively, which were used in place of the acetic acid contained in the composition of the aforesaid mixed liquid.
  • an acid i.e. benzene sulphonic acid, 4-chloro-3-nitro-benzene-phosphoric acid, picric acid and dibromo maleic acid anhydride, respectively, which were used in place of the acetic acid contained in the composition of the aforesaid mixed liquid.
  • An electrophotographic copying material comprising a support and a photoconductive layer formed on one surface of said support, said layer consisting essentially of an organic photoconductive polymeric material containing therein from 0.1 to 15% by weight, based on the weight of said photoconductive polymeric material, of at least one metal nitrate selected from the group consisting of magnesium nitrate, zinc nitrate, sodium nitrate, potassium nitrate, cuprous nitrate, ferrous nitrate, ferric nitrate, cobalt nitrate, nickel nitrate, aluminum nitrate and manganese nitrate.
  • organic photoconductive polymeric material is at least one substance selected from the group consisting of poly-N-vinyl carbazole, poly-N- dimethyl-amino-acenaphthalene, poly-N-vinyl-nitro carbazole, polyvinyl napthalene, polyvinyl-N-dimethyl-amino carbazole, poly-N-diethyl-amino acenaphthalene, polyvinyl anthracene and polyvinyl nitronapthalene.
  • organic photoconductive polymeric material further contains from 0.1 to 2% by weight, based on the weight of said photoconductive polymeric material, of at least one sensitizing dyestuff selected from the group consisting of Rhodamine B (C.I. No. 45170), Rhodamine G (C.I. No. 45150), Rhodamine S (C.I. No. 45050), Methyl Violet (C.I. No. 42535), Ethyl Violet (C.I. No. 42600), Crystal Violet (C.I. No. 42555), Methylene Blue FZ (C.I. NO. 52015), Methylene Blue BH (C.I. No. 52015), Victoria Blue B (C.I.
  • An electrophotographic copying material comprising support and a photoconductive layer formed on one surface of said support, said layer consisting essentially of an organic photoconductive polymeric material containing therein from 0.1 to 15 by weight, based on the weight of said photoconductive polymeric material, of at least one metal nitrate selected from the group consisting of magnesium nitrate, zinc nitrate, sodium nitrate, potassium nitrate, cuprous nitrate, ferrous nitrate, ferric nitrate, cobalt nitrate, nickel nitrate, aluminum nitrate and manganese nitrate, and from 5 to 50% by weight, based on the weight of said metal nitrate, of at least one organic acid selected from the group consisting of organic carboxylic acids, organic sulphonic acids, organic phosphoric acids, nitrophenols and acid anhydrides.
  • organic photoconductive polymeric material is at least one substance selected from the group consisting of poly-N-vinyl carbazole, poly-N- dimethyl-amino-acenaphthalene, poly-N-vi-nyl-nitro carbazole, polyvinyl naphthalene, polyvinyl-N-dimethylamino carbazole, poly-N-diethyl-amino-acenaphthalene, polyvinyl anthracene and polyvinyl nitronaphthalene.
  • organic photoconductive polymeric material further contains from 0.1 to 2% by weight, based on the weight of said photoconductive polymeric material, of at least one sensitizing dyestuff selected from the group consisting of Rhodamine B (C.I. No. 45170), Rhodamine G (C.I. No. 45150), Rhodamine S (C.I. No. 45050), Methyl Violet (C.I. No. 42535), Ethyl Violet (C.I. No. 42600), Crystal Violet (C.I. NO. 42555), Methylene Blue FZ (C.I. No. 52015), Methylene Blue BH (C.I. No. 52015), Victoria Blue (C.I. No.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Photoreceptors In Electrophotography (AREA)
US713893A 1967-03-23 1968-03-18 Electrophotographic copying paper Expired - Lifetime US3552959A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3870644A (en) * 1969-02-10 1975-03-11 Ricoh Kk Liquid developer for plural-color electrophotography
US4160666A (en) * 1977-05-25 1979-07-10 Eastman Kodak Company Polymeric chemical sensitizers for organic photoconductive compositions

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3870644A (en) * 1969-02-10 1975-03-11 Ricoh Kk Liquid developer for plural-color electrophotography
US4160666A (en) * 1977-05-25 1979-07-10 Eastman Kodak Company Polymeric chemical sensitizers for organic photoconductive compositions

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DE1772034A1 (de) 1970-10-22
DE1772034B2 (de) 1972-04-06
BE712742A (nl) 1968-07-31

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