US3585027A - Electrophotographic copying material and its manufacturing method - Google Patents

Electrophotographic copying material and its manufacturing method Download PDF

Info

Publication number
US3585027A
US3585027A US734917A US3585027DA US3585027A US 3585027 A US3585027 A US 3585027A US 734917 A US734917 A US 734917A US 3585027D A US3585027D A US 3585027DA US 3585027 A US3585027 A US 3585027A
Authority
US
United States
Prior art keywords
electrophotographic copying
copying materials
solution
light
materials
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US734917A
Other languages
English (en)
Inventor
Sakae Shimizu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Application granted granted Critical
Publication of US3585027A publication Critical patent/US3585027A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • G03G5/05—Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers
    • G03G5/0528—Macromolecular bonding materials
    • G03G5/0532—Macromolecular bonding materials obtained by reactions only involving carbon-to-carbon unsatured bonds
    • G03G5/0542—Polyvinylalcohol, polyallylalcohol; Derivatives thereof, e.g. polyvinylesters, polyvinylethers, polyvinylamines
    • 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
    • G03G5/05—Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers
    • G03G5/0528—Macromolecular bonding materials
    • G03G5/0532—Macromolecular bonding materials obtained by reactions only involving carbon-to-carbon unsatured bonds
    • G03G5/0546—Polymers comprising at least one carboxyl radical, e.g. polyacrylic acid, polycrotonic acid, polymaleic acid; Derivatives thereof, e.g. their esters, salts, anhydrides, nitriles, amides

Definitions

  • An electrophotographic copying material comprising a support and a light-sensitive or photoconductive layer formed on one surface of said support, said photoconductive layer being formed in such a way that a photoconductive layer-forming solutionwhich is prepared by dispersing a photoconductive substance in a basic aqueous solution containing a polybasic acid monoester of a polyvinyl acetate and also a volatile basic substanceis applied onto said one surface of said support and then dried.
  • the present invention is concerned with an electrophotographic copying material provided, on one surface of its support, with a photoconductive layer wherein a novel water-soluble polybasic acid monoester of a polyvinyl acetate is used as the binder resin for the components constituting said photoconductive layer, said electrophotographic copying material being featured by its excellent electrostatic characteristics which are exhibited even in an atmosphere of high temperature and high relative humidity.
  • the binder consists of a resin which is soluble in water
  • the electrophotographic copying materials which were prepared according to these proposals had the drawbacks in their electrostatic characteristics such that the light-sensitive layers which were impressed with an electric charge exhibited a low charge potential and also that they showed a large amount of dark decay, which is the decrease in the potential exhibited by the copying materials during the period in which they are left to stand after having been impressed with an electric charge.
  • the electrophotographic copying materials of the prior art were too unsatisfactory to be used for practical purposes.
  • a primary object of the present invention to provide an. electrophotographic copying material having a light-sensitive layer wherein a binder which is soluble in alkaline aqueous solutions is used as one of the components for constituting the light-sensitive layer.
  • Another object of the present invention is to provide an electrophotographic copying material which exhibits electrostatic characteristics which are substantially the same in degree and extent as those exhibited by the conventional electrophotographic copying materials wherein a binder which is soluble in organic solvents is used as a component of the light-sensitive layers.
  • Still another object of the present invention is to provide an electrophotographic copying material which exhibits superior electrostatic characteristics even in an atmosphere of high temperature and high relative humidity.
  • the present invention has been discovered based on the knowledge which was obtained from extensive research conducted on the electrostatic characteristics of the electrophotographic copying materials which were produced by forming-on one side of a support consist ing of a metal plate or a paper sheet whose reverse side having been processed to have an electroconductivity a light-sensitive layer with a combination of a zinc oxide which is a photoconductive substance and a water-soluble resin as the binder, and also as the result of a number of experiments in which a variety of water-soluble resins were used.
  • the resulting electrophotographic copying material exhibits excellent electrostatic characteristics which are not inferior to those exhibited by the conventional electrophotographic copying materials utilizing the binders which are soluble in organic solvents.
  • the polybasic acid monoesters of polyvinyl acetate which are used in the present invention refer to those substances which are obtained from a reaction between a polybasic acid which is represented by such acids as maleic acid and itaconic acid and a polyvinyl acetate. It is to be noted, however, that the substances which are obtained from the foregoing reaction are featured by the fact that the unsaturated radicals of the polybasic acid used are retained as they were in these substances, and accordingly, the substances which are obtained from said reaction differ in chemical properties from the so-called ordinary copolymers of polyvinyl acetate and polybasic acids.
  • the monoester which is obtained from the reaction between maleic acid and a polyvinyl acetate will have the following chemical structure:
  • the polybasic acids which are referred to in the present invention are directed to those unsaturated carboxylic acids having two or more carboxyl radicals in one molecule.
  • These unsaturated carboxylic acids include, for example,
  • fumaric acid in addition to the aforesaid maleic acid and itaconic acid.
  • the use of those monoesters which are produced as the result of the coupling of a polyvinyl acetate to one of the aforesaid polybasic acids of an amount ranging from 2% to 30% by mole are most desirable.
  • the photoconductive substances for being dispersed in resins consisting of such polybasic acids as those described above to prepare lightsensitive layer-forming solutions there can be employed all of those known photoconductive substances such as zinc oxide, titanium oxide, zinc sulfide, zinc selenide and cadmium sulfide.
  • the inclusion-in the light-sensitive layers of the electrophotographic copying materials of those dyestuffs such as Rose Bengal, Fluorescein, Bromophenol Blue, Tetrabromophenyl Blue, Methylene Blue and Methyl Violet, which are known as the sensitizers for use in electrophotography in general not only will not be harmful, but also are even desirable.
  • those dyestuffs such as Rose Bengal, Fluorescein, Bromophenol Blue, Tetrabromophenyl Blue, Methylene Blue and Methyl Violet
  • the supports which can be applied to the present invention the use of paper sheets, films or the like which have been given an electroconducting treatment by the application of or by being impregnated with an electroconductive substance such as surface active agents, in addition to the use of metal plates, is also desirable.
  • the binder resins which consist of those aforesaid polybasic acid monoesters of polyvinyl acetates and which can be applied to the present invention all have a property such that they become water-soluble for the first time by the addition thereto of a basic substance such as alkali or amines.
  • the aforesaid binder resins are made to be soluble in water by the addition thereto of at least one of the volatile basic substances, such as ammonia, triethylamine, trimethylamine, diethylamine, dimethylamine, ethylamine methylamine, methylethylamine, diisopropylamine and methyldiethylamine, of all the substances which are called basic substances, these volatile substances such as ammonia or trimethylamine which are made to be contained in the light-sensitive layers of the electrophotographic copying materials which are manufactured by the use of the aforesaid mixed solution will evaporate and disappear during the drying step in the process of forming the light-sensi tive layers, and accordingly, the binder resins will change to non-soluble in water and at the same time will gain a markedly increased electric resistance.
  • the volatile basic substances such as ammonia, triethylamine, trimethylamine, diethylamine, dimethylamine, ethylamine methylamine, methyl
  • the binder resins are made to be soluble in Water by the addition thereto of a water-soluble substance such as hydrogen peroxide which has a catalytic action, together with one of the aforesaid desirable basic substances, the resulting light-sensitive layers of the electrophotographic copying materials which are manufactured by the use of these substances will exhibit better electrostatic character istics.
  • This effect is considered to result from the fact that, owing to the reactivity of the unsaturated radicals contained in the polybasic acid which is united to the polyvinyl acetate, there occurs a reaction between the monoester molecules causing them to be united to each other, and that, as a result, these monoester molecules are converted, during the drying step in the process of forming light-sensitive layer, to a polymer having a three dimensional chemical structure.
  • the present invention contemplates the provision of an electrophotographic copying material by first applying, onto one surface of a support, an aqueous solution of light-sensitive layer-forming components which are comprised essentially of a photoconductive substance and a binder resin consisting of a polybasic acid monoester of a polyvinyl acetate, and then drying the applied solution.
  • the electrophotographic copying material thus obtained not only will exhibit superior electrostatic characteristics in a normal atmosphere, but also will exhibit equally superior electrostatic characteristics even in an atmosphere of high temperature and high relative humidity.
  • the electrophotographic copying material of the present invention possesses properties which are superior to those of the commercially available electrophotographic copying materials of the prior art.
  • the curves 1 and 1 represent the electrostatic characteristics of the electrophotographic copying materials obtained in the Example 1 which will be described later, while the cnrves 2 and 2 and the curves 3 and 3' represent the electrostatic characteristics of the control copying materials, respectively.
  • the conditions under which these curves were obtained will be described in detail in Example 1.
  • Example 1 A photoconductive substance-dispersed solution (A) consisting of:
  • Zinc oxide A dispersing agent sodium salt of polyacrylic acid
  • a binder resin solution was prepared by dissolving a copolymer of a vinyl acetate and crotonic acid (a basic acid) in a mixed solution of water and an ammonia water, while on the other hand, preparing a photoconductive substance solution in which zinc oxide and a dispersing agent were dispersed in water.
  • control copying materials (b) were also prepared by mixing Latex which was a copolymer of styrene and butadiene in a photoconductive substance-dispersed solution having a composition identical to that used in the production of the copying materials of the present invention, and thereafter using the resulting solution in a manner similar to that employed in the manufacture of the product of the present invention.
  • the drawing is a graph of the electrostatic characteristics in which are plotted the changes occurring in the potential of the light-sensitive layers during the period from the time the electrophotographic copying materials thus obtained were impressed with an electric charge (charge on) by corona discharge till the time immediately after they were exposed to light (light on).
  • the curves 1 and 1 show the electrostatic characteristics of the copying materials of the present invention
  • the curves 2 and 2' show those of the control copying materials (a)
  • the curves 3 and 3' show those of the control copying materials (b), respectively.
  • the curves 1, 2 and 3 represent the results of the measurements which were conducted on these copying materials at 20 C. and a R.H. of 65%
  • the curves 1, 2' and 3' represent the result of the measurements which were performed on the copying materials at 30 C. and a R.H. of 80%.
  • the copying materials of the present invention show a quicker rise of the potential when the copying materials are impressed with an electric charge, and show a smaller amount of dark decay which means the attenuation of the potential from right after the suspension of the charging (charge off) till the time the copying materials are exposed to light, and also show quicker light decay which is exhibited when the copying materials are exposed to light, as compared with the control copying materials, and thus, it will be understood clearly that the electrophotographic copying materials of the present invention sufficiently satisfy the electrostatic characteristic qualifications which are required of electrophotographic copying materials. It was also noted in this example that the control copying materials (2.) exhibited satisfactory abilities in a normal atmosphere (which means a temperature of 20 C. and a R.H.
  • control copying materials (b) were altogether unsuitable for being used for practical purposes.
  • the aforesaid respective types of electrophotographic copying materials were then used in taking copies by the use of an electrophotographic copying apparatus (which is manufactured and sold by K. K. Ricoh of Japan under the trade name of Ricoh Electronic Printer BS-l), with the result that very clear copied images were formed on the copying materials of the present invention (the reflection density of the copied images measured by a densitometer manufactured by Photovolt Company of USA. was noted t be 1.50 or over), in contrast to the slightly obscure copied images which were formed on the control copying materials (a), namely, the reflection density of the copied images was in the order of 0.8. Also, in case the copying operation was conducted in an atmosphere of a high temperature and a high relative humidity, the copying materials of the present invention showed the formation of satisfactory copied images, whereas there was formed entirely no copied image on the control coping materials (a).
  • Example 2 A binder resin solution which was composed of:
  • Gr. Fumaric acid monoester of polyvinyl acetate (a 12% by mole monoesterified compound manufactured and sold under the trade name of M-50 (Z7) the Nippon Synthetic Chemical Industry Co.,Ltd.) 20 Hydrogen peroxide solution (35% or over) 0.6 Ammonia water (28%) 10 Diethylamine 5 Ethanol 10 A sensitizer dye (Rose Bengal) 0.004 Water 50 was mixed in a photoconductive substance-dispersed solution having a composition identical to the solution (A) used in Example 1, and the resulting mixed solution was dispersed thoroughly by the use of a homogenizing mixer for 15 minutes. Thus, a solution for forming light-sensitive layers was prepared.
  • control electrophotographic copying materials were prepared by the use of a water-soluble alkyd resin, a water-soluble, acrylic resin, a melamine formaldehyde resin, a urea formaldehyde resin, a polyvinyl acetatevinyl chloride copolymer Latex, a polystyrene-butadiene copolymer Latex and a vinyl chloride resin Latex as the binder resins, respectively, and in a manner similar to that described in this instant example. Then, these control electrophotographic copying materials were measured as regards their electrostatic characteristics and also were subjected to copying operation in a manner similar to that described in Example 1. The result was that these copying materials exhibited electrostatic characteristics which where were substantially the same with those indicated by the curve 3 in the drawing, but there was formed entirely no copied image at all.
  • Example 3 A binder solution having a composition identical to that of the solution (B) of Example 1 with the exception that the maleic acid monoester of polyvinyl acetate was substituted by itaconic acid monoester of polyvinyl acetate which was a 8% by mole monoesterified compound manufactured and sold under the trade name of A-75 (Z2) by the Nippon Synthetic Chemical Industry Co., Ltd., was prepared. This solution was placed, together with a photoconductive substance-dispersed solution having a composition identical to the solution (A) of Example 1, in a homogenizing mixer and they were dispersed and mixed for minutes. Thus, a solution for forming light-sensitive layers was prepared.
  • Example 4 By the use of a binder resin which was a mixture of 7 parts by weight of the binder resin used in Example 2, and 3 parts by weight of fumaric acid monoester of polyvinyl acetate which was a by mole monoesterified compound manufactured and sold under the trade name of E-50 (Z2) by the Nippon Synthetic Chemical Industry Co., Ltd., there was prepared a binder resin solution in such a way that the solution had a composition identical to that used in Example 2. By using this binder resin solution in a manner similar to that described in Example 2, electrophotographic copying materials were obtained. These copying materials were subjected to copying operation by the use of a copying apparatus similar to that used in Example 1, with the result that very clear copied images were obtained. These copying materials were measured of their electrostatic characteristics. The result, was that they exhibited electrostatic characteristics which were of the same order to those indicated by the curve exhibited by the product of the present invention in the drawing.
  • a method for manufacturing an electrophotographic copying material comprising the steps of:
  • methylethylamine, diisopropylamine and methyldiethylamine said monoester being obtained by monoesterifying an acid selected from the group consisting of maleic acid, itaconic acid and fumaric acid with polyvinyl acetate;
  • a method according to claim 1, wherein said monoester is formed by esterifying polyvinyl acetate with from 2 mol percent to 30 mol percent of said acid.
  • an electrophotographic copying material comprising an electroconductive support and a photoconductive layer on one surface of said support, said layer comprising a photoconductive substance dispersed in a hinder
  • said binder consists essentially of a polybasic acid monoester of polyvinyl acetate
  • said photoconductive substance is selected from the group consisting of zinc oxide, titanium oxide, zinc sulfide, zinc selenide and cadmium sulfide, said monoester being obtained by monoesterifying an acid selected from the group consisting of maleic acid, itaconic acid and fumaric acid with polyvinyl aetate.

Landscapes

  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Photoreceptors In Electrophotography (AREA)
US734917A 1967-06-30 1968-06-06 Electrophotographic copying material and its manufacturing method Expired - Lifetime US3585027A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP4155967 1967-06-30
JP4426667 1967-07-10

Publications (1)

Publication Number Publication Date
US3585027A true US3585027A (en) 1971-06-15

Family

ID=26381200

Family Applications (1)

Application Number Title Priority Date Filing Date
US734917A Expired - Lifetime US3585027A (en) 1967-06-30 1968-06-06 Electrophotographic copying material and its manufacturing method

Country Status (5)

Country Link
US (1) US3585027A (forum.php)
BE (1) BE717297A (forum.php)
DE (1) DE1772735C3 (forum.php)
GB (1) GB1230108A (forum.php)
NL (1) NL145057B (forum.php)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3885961A (en) * 1972-08-01 1975-05-27 Mitsubishi Rayon Co Polymeric binder material for use in a photoconductive layer employed in electrophotography
US4252883A (en) * 1972-04-28 1981-02-24 Canon Kabushiki Kaisha Process for producing electrophotographic photosensitive member
US4521503A (en) * 1984-05-11 1985-06-04 Minnesota Mining And Manufacturing Company Highly photosensitive aqueous solvent-developable printing assembly

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4252883A (en) * 1972-04-28 1981-02-24 Canon Kabushiki Kaisha Process for producing electrophotographic photosensitive member
US3885961A (en) * 1972-08-01 1975-05-27 Mitsubishi Rayon Co Polymeric binder material for use in a photoconductive layer employed in electrophotography
US4521503A (en) * 1984-05-11 1985-06-04 Minnesota Mining And Manufacturing Company Highly photosensitive aqueous solvent-developable printing assembly

Also Published As

Publication number Publication date
NL6809175A (forum.php) 1968-12-31
DE1772735A1 (de) 1970-08-27
GB1230108A (forum.php) 1971-04-28
DE1772735C3 (de) 1973-12-20
NL145057B (nl) 1975-02-17
BE717297A (forum.php) 1968-12-02
DE1772735B2 (de) 1972-07-20

Similar Documents

Publication Publication Date Title
US3745005A (en) Electrophotographic elements having barrier layers
DE69107072T2 (de) Vernetzte leitende polymere und diese enthaltende antistatische beschichtungen.
US3778264A (en) Zinc oxide photoconductive element with an epoxy group containing interlayer
DE2801913C2 (de) Elektrophotographisches Aufzeichnungsmaterial
DE2322046C3 (de) Verfahren zum Herstellen von Druckformen
DE2721827A1 (de) Fuer offsetdruck und lithographie geeignetes elektrophotographisches lichtempfindliches material sowie verfahren zu dessen herstellung
US3585027A (en) Electrophotographic copying material and its manufacturing method
US4165308A (en) Coating compositions comprising polymer blends containing polystyrene or poly(α-methyl styrene)
US3652268A (en) Barrier coated electrophotographic sheet suitable for liquid development
US3563736A (en) Photoconductive coatings
US3041168A (en) Electrostatic printing
US3966471A (en) Electro photosensitive materials with a protective layer
US3595647A (en) Copying material for use in high-speed electrophotography
US3761259A (en) Electrophotographic element containing an intermediate layer
DE2452623C2 (de) Elektrophotographisches Aufzeichnungsmaterial
DE1522548A1 (de) Elektrophotographisches Aufzeichnungsmaterial
DE2558916A1 (de) Ueberzugsmasse
US4435493A (en) Porous reusable ZnO electrophotographic element
US3622368A (en) Method for developing electrostatic latent images by utilizing coupling reaction
DE2558999A1 (de) Elektrostatisches aufzeichnungsmaterial und verfahren zu seiner herstellung
US3778263A (en) Zinc oxide photoconductive element with starch reaction product interlayer
US3904410A (en) Electrophotographic copying paper
DE1284297B (de) Entwicklerschicht fuer das Diazotypieverfahren
DE2328578A1 (de) Elektrofotografisches verfahren zur herstellung sichtbarer bilder
US3631514A (en) Recording film having removable antistatic layer