JPH11295912A - Electrophotographic photoreceptor, method for image forming, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoreceptor furnished with the excellent size stability regardless of the use at the high temp. over a long period and the image property at the time of repeatingly using, and a method for the image forming and an image forming device adopting the same. SOLUTION: In this electrophotographic photoreceptor 10 composed by providing a conductive layer and a photoreceptor layer on a light-transmissive substrate, respective thermal fluctuation ratio of the photoreceptor shown by the next formula, S1=(Y-m)/m×100 and S2=(Z-n)/n×100, is set to 100 or below, and then Y and Z is respectively set to 80 μm or below, where Y is the roundness based on the surface at the time of retaining the photoreceptor in a upright state for 1 hr. at 110 deg.C, (m) is the roundness based on the surface at the time of retaining the photoreceptor in a upright state for 24 hr. at 20 deg.C, Z is the roundness based on the surface at the time of retaining the photoreceptor in a upright state for 1 hr. at 110 deg.C, and (n) is the roundness based on the surface at the time of retaining the photoreceptor in a upright state for 24 hr. at 20 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, etc., in which a charging means, an image exposing means and a developing means are arranged around a drum-shaped image forming body so as to be monochrome or superposed. The present invention relates to an electrophotographic photosensitive member used for an electrophotographic system for forming a color image, a color image forming method, and an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, as a method of forming a multicolor image, the same number of image forming bodies (photoconductors), image exposing means, charging means, developing means and the like as the number of colors required for image formation are provided. A color image forming apparatus in which a single color toner image formed on an image forming body is superimposed on a transfer material to form a color image, or the image forming body is rotated a plurality of times to repeatedly charge, image expose and develop each color to form a color image. A color image forming apparatus for forming an image, and a color image forming apparatus for forming a color image by sequentially performing charging, image exposure and development within one rotation of an image forming body are also known.

However, each of the above image forming apparatuses is provided with the same number of image forming bodies, image exposing means, charging means, developing means, etc. as the number of colors necessary for image formation. A color image forming apparatus that forms a color image by superimposing it on a transfer material has a drawback that the volume of the apparatus is increased due to the need to transport a plurality of image forming bodies and the transfer material. In a color image forming apparatus that forms a color image by repeating charging, image exposure, and development for each color, the volume of the image is reduced, but the size of the formed image is limited to the surface area of the photoconductor or less. There are restrictions.

[0004] In this respect, a color image forming apparatus which forms a color image by sequentially performing charging, image exposure and development within one rotation of the image forming body has no restriction on the size of the image and is capable of high-speed image formation. And so on. Furthermore,
Japanese Patent Application Laid-Open No. Hei 5-307307 proposes a device in which a transparent substrate is used as a substrate of an image forming body and an image exposing means is arranged inside the image forming body to reduce the size of the apparatus.

[0005]

However, in the above-described color image forming apparatus, since the focal depth of the SELFOC lens as an equal-magnification imaging element used in the image exposure means is as small as about ± 100 μm, the transparent resin substrate When the thickness unevenness is present, the focus of the image exposure light by the image exposure means is not properly focused, and unevenness in image formation (pintmura) occurs, resulting in a problem that a good color image is not formed due to image blur. In addition, during non-contact development on a drum-shaped image forming body using a transparent resin substrate, Ds due to a change in the outer diameter of the transparent resin substrate was determined.
There is a problem that development unevenness occurs at d (development gap) and the image density fluctuates. Further, since the image forming body has a structure in which the substrate is placed in the optical path of the image exposure, the thermal expansion due to the rise of the environmental temperature and the heat of the light source for the image exposure or the influence of distortion and uneven rotation due to the pressure contact of the developing means and the cleaning means, There is a problem that the registration between the superimposed images fluctuates or the image is defocused to cause a color deviation and deteriorate the image quality.

According to the present invention, this point is improved so that unevenness in image formation (pintmura) of image exposure light hardly occurs, unevenness in development during non-contact development hardly occurs, and sufficient strength against external force is obtained. A color image forming apparatus capable of forming a high-quality color image at a high speed by realizing a drum-shaped image forming body (photoreceptor) of a light-transmitting resin substrate which is capable of responding to a temperature change. Can be provided.

That is, an object of the present invention is to provide a photoreceptor which has good long-term storage properties, high dimensional stability of the photoreceptor even when used at high temperatures for a long period of time, and has good image characteristics when used repeatedly. An object of the present invention is to provide a color image forming method and an image forming apparatus.

[0008]

The above object is achieved by adopting one of the following constitutions.

[1] In an electrophotographic photosensitive member in which a conductive layer and a photosensitive layer are provided on a light-transmitting substrate, the thermal fluctuation coefficients S1 and S2 of the photosensitive member represented by the following formula are 100 or less, and Y
And an electrophotographic photoreceptor, wherein Z is 80 μm or less.

S1 = (Y−m) / m × 100 S2 = (Z−n) / n × 100 where Y is the reference value of the surface of the photoconductor when stored at 110 ° C. for 1 hour with the photoconductor upright. Roundness m: Roundness based on the surface of the photoconductor when stored at 20 ° C. for 24 hours with the photoconductor standing Z: Surface of the photoconductor when stored at 110 ° C. for 1 hr with the photoconductor standing Reference cylindricity n: Surface-based cylindricity of the photoconductor when stored at 20 ° C. for 24 hours with the photoconductor upright [2] It is an electrophotographic photoconductor for internal exposure [1] The electrophotographic photosensitive member according to the above.

[3] The electrophotographic photosensitive member according to [1], wherein the translucent substrate is a resin synthesized from a vinyl monomer.

[4] The electrophotographic photosensitive member according to [1], wherein the translucent substrate is made of a crosslinkable synthetic resin.

[5] The electrophotographic photosensitive member according to [1], wherein the translucent substrate is made of a resin synthesized by a centrifugal polymerization method.

[6] The surface of the electrophotographic photoreceptor is uniformly charged, and image exposure and color development are repeated to form a multicolor superimposed image, which is subjected to batch transfer, separation, fixing, and photoreceptor cleaning steps. In an image forming apparatus for forming an image, the photoconductor described in [1] is used as an electrophotographic photoconductor,
An image forming apparatus, wherein an image is exposed through a translucent substrate and an image is formed by non-contact development.

[7] A step of uniformly charging the surface of the electrophotographic photosensitive member, an image exposing step, and a color developing step are repeated to form a multicolor superimposed image, a batch transfer step, a separating step, a fixing step, and a photosensitive step. In the image forming method which goes through each step of the body cleaning, the photoreceptor described in [1] is used as the electrophotographic photoreceptor, the image is exposed through a translucent substrate, and the image is formed by non-contact development. Image forming method.

Conventionally, in order to obtain a good image stably,
The roundness required for the substrate for internal exposure is 80
μm or less, and a cylindricity of 80 μm or less. However, unlike a metal substrate such as an aluminum substrate, a synthetic resin substrate can maintain the initial accuracy within the standard, but in the case of long-term storage, for example, six months, even under conditions where temperature control is firm, the drum itself can be used. Due to the weight applied by the weight, plastic deformation occurs and the predetermined accuracy cannot be maintained.
It is exposed to a high temperature of about 00 ° C. for about 1 hour. In such a case, the lower part of the base is deformed by its own weight. Further, during copying for a long time, the temperature of the housing portion of the photoconductor rises due to heat from the exposure light source inside the photoconductor, the developing device, the cleaning device, the fixing device, and the like, and may reach about 80 ° C. Further, a cleaning blade and a developing device are pressed against the photosensitive member. In such a situation, the synthetic resin base is deformed, and a long-term stable good image cannot be obtained.

Therefore, the definition of the roundness and cylindricity of the photosensitive member must be adapted to such a situation.
That is, it has been found that a good image can be obtained with good stability for the first time by setting a prescribed value in consideration of the long-term storage and the fluctuation rate due to heat and setting the prescribed value or less.

That is, at the time of manufacturing the substrate or the completion of the photoconductor,
It was found that not only the roundness and cylindricity were within the specified range, but also the thermal fluctuation rate in consideration of the plastic deformation after storage of the photoconductor and the deformation at the time of copying a large number of sheets was required to be within the specified circle.

In the above defined values of the present invention, Y and Z are 8
If it is larger than 0 μm, or if S1 and S2 are 100
Is exceeded, the image forming position of the exposure system shifts, or the development is biased, causing image blur, image distortion, and image unevenness. The values of Y and Z are more preferably 50 μm.
m, particularly preferably 30 μm or less.

The method of controlling the thermal fluctuation rate of the photoreceptor substrate is not particularly limited, but may be selected from monomers, a curing agent, curing conditions, a molding method and conditions, such as a casting polymerization method. This can be done by optimizing the production conditions at

In the present invention, the roundness of the surface of the photoreceptor means a difference between a maximum circumscribed diameter and a minimum circumscribed diameter of the photoreceptor surface. Further, the cylindricity refers to a difference in radius between a maximum circumscribed diameter and a minimum circumscribed diameter on the surface of the photoconductor in the same photoconductor. These are specified in JIS B-0021.

Hereinafter, embodiments of the present invention will be described.

The description in this column does not limit the technical scope of the claims and the meaning of terms. Also, the following assertive description in the embodiment of the present invention indicates the best mode, and does not limit the meaning of the terms of the present invention or the technical scope.

The translucent substrate for an electrophotographic photosensitive member in the present invention is produced by a centrifugal polymerization method, injection molding, extrusion molding or the like. The production by the centrifugal polymerization method, which is a typical production method, will be specifically described as shown in FIG.
Shows an example of a manufacturing apparatus. In the manufacturing apparatus of FIG.
Reference numeral 1 denotes a cylindrical mold whose inner surface is polished to form a highly accurate cylindrical surface. C2 is a heating member for heating from outside the mold C1. C3 is a mold holding member that sandwiches the mold C1 from the left and right, so that the liquid inside the mold C1 does not leak in the sandwiched state. C4 is an inlet for injecting the polymerizable liquid material. C5 is a thermometer for measuring the temperature inside the mold C1. This device is adjusted so that the axis of the mold C1 is horizontal,
It is structured to rotate at high speed after injecting the polymerizable liquid material. After the molding, the cylindrical substrate is taken out by moving one of the mold holding members C3 in the direction of arrow B.

In the manufacturing process shown in FIG. 1, first, a vinyl polymerizable liquid material, for example, methyl methacrylate monomer, is used, and a polymerization initiator is added to rapidly polymerize the liquid, and the viscosity is 10 cp to 400 cp. And pour into cylindrical mold C1. This cylindrical mold usually has an inner diameter of 20 mm or more and 200 mm or less, and a length of 200 mm or more and 2000 mm or less. This is rotated for each mold and is heated appropriately to promote uniform polymerization. After completion of the polymerization, the substrate is cooled to a temperature close to room temperature (annealing treatment), the obtained substrate is taken out of the mold, cut, and if necessary, subjected to a finishing step to complete the translucent substrate for an electrophotographic photosensitive member.

The above-mentioned centrifugal polymerization method preferably used in the present invention does not leave dice scratches on the surface of the cylindrical substrate, and particularly, the inner surface is formed into a natural surface obtained by centrifugal force, and is extremely smooth such as a glass surface. To form a smooth inner surface.

Preferred materials for preparing the substrate of the present invention include a radically polymerizable monomer (monomer, a monomer having no crosslinkability) and a polyfunctional vinyl compound (a monomer having crosslinkability). Are copolymerized in the presence of a radical polymerization initiator, but are preferably crosslinked from the viewpoint of heat resistance, solvent resistance and dimensional stability.

This will be described in more detail below.

The radically polymerizable monomers used in the present invention include styrene, α-methylstyrene, m-
Side chain alkyl-substituted styrene such as methylstyrene and p-methylstyrene, core alkyl-substituted styrene such as vinyltoluene, p-chlorostyrene, o-chlorostyrene, m-
Chlorostyrene, p-bromostyrene, o-bromostyrene, m-bromostyrene, 2,4-dichlorostyrene, 2,4-dibromostyrene, 4-chloro-α-methylstyrene, 4-bromo-α-methylstyrene, 2,
Halogenated styrene such as 4,6-trichlorostyrene, 2,4,6-tribromostyrene, pentachlorostyrene, pentabromostyrene, vinyl benzoate, 2-vinylnaphthalene, 4-vinylbiphenyl, 1,1'-diphenyl Aromatic vinyl monomers such as ethylene, acrylonitrile, methacrylonitrile, fumaronitrile, maleonitrile, vinyl cyanide monomers such as α-chloroacrylonitrile, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl Methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, stearyl methacrylate, Cutyl methacrylate, cyclohexyl methacrylate, allyl methacrylate, dicyclopentanyl methacrylate, norbornyl methacrylate, adamantyl methacrylate, isobornyl methacrylate, phenoxyethyl methacrylate, phenyl methacrylate, benzyl methacrylate, naphthyl methacrylate, butoxyethyl methacrylate, methyl acrylate, ethyl acrylate (Meth) such as propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, dodecyl acrylate, phenyl acrylate, benzyl acrylate, etc.
(Meth) acrylic acids such as alkyl acrylates, methacrylic acid and acrylic acid, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, OH group-containing (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate, epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate, and N-containing such as N, N-diethylaminoethyl (meth) acrylate. Ether-containing (meth) acrylates such as (meth) acrylates, butoxytriethylene glycol (meth) acrylate, and ethoxydiethylene glycol (meth) acrylate, maleic acid, maleic anhydride, dimethyl maleate, and dibutyl maleate. Maleic acid, maleic acid esters such as dibenzyl malate, itaconic acid, itaconic anhydride, benzyl itaconate, itaconic acid such as dibenzyl itaconate, itaconic acid esters, fumaric acid, dimethyl fumarate, dibutyl fumarate , Fumaric acid esters such as diisopropyl fumarate, dibenzyl fumarate, dicyclohexyl fumarate, and the like; and other monomers such as vinyl acetate, vinyl chloride, vinylidene chloride, N-alkylmaleimides,
-Phenylmaleimides and mixtures thereof are preferably used. More preferably, the radical polymerizable monomer contains methyl methacrylate in an amount of 20% by weight or more, preferably 40% by weight or more.

The polyfunctional vinyl compound (crosslinkable monomer) used in the present invention includes divinylbenzene, metadivinylbenzene, 4,4'-divinylbiphenyl,
3'-divinylbiphenyl, 3,4'-divinylbiphenyl, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,4-
Butanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, divinyl phthalate, diallyl phthalate, divinyl isophthalate, diallyl isophthalate, divinyl terephthalate, diallyl terephthalate, diallyl naphthenate, tri One or more selected from allyl isocyanurate, diallyl carbonate, diethylene glycol bisallyl carbonate and the like are used in combination as a crosslinking agent. The addition amount of the crosslinking agent is used in the range of 0.05 to 90% by weight based on the total amount of the raw material monomers (radical polymerizable monomer + polyfunctional vinyl compound). If the content is less than 0.05% by weight, the heat resistance may not be satisfactory. If the content is more than 90% by weight, the polymer becomes hard but brittle, so that the mechanical durability may be poor.

The radical polymerization initiator used in the polymerization of the synthetic resin for a base used in the present invention is not particularly limited.
Any material that generates active radicals by active energy rays such as visible light, infrared light, ultraviolet light, microwaves, electron beams, or heat can be used.

Radical polymerization initiators which generate active radicals by heat include benzoyl peroxide, diisopropylperoxydicarbonate, t-butylperoxy-2-ethylhexanoate, t-butylperoxypivalate, and t-butylperoxydiisobu. There are tyrates, lauroyl peroxide, t-butylperoxyacetate, t-butylperoxyoctoate, t-butylperoxybenzoate, di-t-butylperoxide, azobisisobutyronitrile and the like.

As a radical polymerization initiator for generating an active radical by an activation energy ray, acetophenone,
Benzophenone, benzoin, benzoin methyl ether, 2-hydroxy-2-methyl-1-phenylpropan-1-one, hydroxycyclohexylphenyl ketone, methylphenylglyoxylate, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzyl There are dimethyl ketal and the like, and they can be used alone or as a mixture when used.

The mixing ratio of the radical polymerization initiator varies depending on the type of the radical polymerization initiator, the type of the vinyl monomer, the polymerization curing temperature, and the like. In general, the mixing ratio is based on 100 parts by weight of the copolymerizable vinyl monomer. And preferably 0.01 to 8 parts by weight, particularly preferably 0.1 to 5 parts by weight. If the mixing ratio of the radical polymerization initiator is less than 0.01 part by weight, it takes a long time for the polymerization to cure or the polymerization is not completed, which is not preferable. If the amount of the polymerization initiator exceeds 8 parts by weight, the polymer may become brittle or colored.

The non-vinyl polymer resins constituting the basis of the present invention include polyamide, polyimide, epoxy resin, polycarbonate, polysulfone, polyethersulfone, polyester, polyarylate, polyphenylene oxide, polybutylene terephthalate, and polyethylene terephthalate. And polymethylpentene.
After injection molding or extrusion molding of these polymer resins, the surface is polished or cut to obtain a desired Rz, whereby the transparent cylindrical substrate of the present invention can be produced.

A non-crosslinked vinyl polymer resin can also be used as a base material in the above-mentioned molding method.

Next, the case where the light-transmitting substrate of the present invention is used for an electrophotographic photosensitive member will be described. The cylindrical substrate of the present invention has a smooth surface, especially in the case of using a polymer of methyl methacrylate, and the transparency is extremely high and the strength is high. It is suitable for an image forming apparatus employing a mechanism for performing exposure from the inside.

A typical example is an electrophotographic photosensitive member having a conductive layer and a photoconductor photosensitive layer provided on the surface of a cylindrical substrate. Conventionally, an electrophotographic photosensitive member has been used to provide the conductive layer and the photoconductor photosensitive layer. The method can be widely used.

That is, as a method for forming the transparent conductive layer, aluminum or ITO (indium tin oxide) is used.
Typical examples thereof include a film formed by vapor deposition or sputtering of a metal or metal oxide, and a conductive resin film formed by mixing a resin with ITO or alumina conductive fine particles.

For improving the adhesion of the photosensitive layer, improving the coating property, covering defects on the substrate, and improving the charge injection property from the substrate to the charge generation layer, an intermediate layer (undercoat layer) is provided below the charge generation layer. May be provided. Examples of the material of the undercoat layer include alcohol-soluble polyamide, copolymerized nylon, alkoxymethylated nylon, vinyl chloride-vinyl acetate copolymer, casein, polyvinyl alcohol, cellulose, gelatin, and metal as described in JP-A-9-68870. A curable undercoat layer using an alkoxide, an organic metal chelate, or a silane coupling agent is used. These have a thickness of 0.01 to 5 μm.
It is applied so that it becomes about.

In order to improve the adhesion and coating properties of the photosensitive layer, improve the coating of defects on the substrate, and improve the charge injection property from the substrate, an undercoat layer or an intermediate layer is usually provided below the photosensitive layer. Good.

In the formation of the photosensitive layer, an inorganic photoconductor layer may be formed by vapor deposition or the like. However, an organic photoconductor layer, particularly a function separation type containing both a charge transport material and a charge generation material, may be used. In particular, it is preferable to form by applying an organic photoreceptor of a type in which each is separately laminated.

The charge generation layer (CGL) is formed by dispersing a charge generation material (CGM) in a binder resin as required. As CGM, metal or metal-free phthalocyanine compounds, bisazo compounds, azo compounds such as trisazo compounds, squarium compounds, azulhenium compounds, perylene compounds, indico compounds, quinacridone compounds, polycyclic quinone compounds, cyanine dyes, xanthene dyes, Examples include, but are not limited to, charge transfer complexes comprising poly-N-vinylcarbazole and trinitrofluorenone. These may be used as a mixture of two or more as necessary. However, in order to achieve the object of the present invention at the highest level, one of perylene compounds, an imidazole perylene compound or a metal phthalocyanine compound, titanyl phthalocyanine (T
iOPc) is preferred.

As the binder resin usable for the charge generation layer, for example, polystyrene resin, polyethylene resin, polypropylene resin, polyacryl resin, polymethacryl resin, polyvinyl chloride resin, polyvinyl acetate resin, polyvinyl butyral resin, Epoxy resins, polyurethane resins, polyphenol resins, polyester resins, polyalkyd resins, polycarbonate resins, polysilicone resins, polymelamine resins, and copolymer resins containing two or more of the repeating units of these resins, for example, vinyl chloride-acetic acid Vinyl copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, and high-molecular organic semiconductor such as poly-N-vinyl carbazole,
And the like, but are not limited thereto. Among the above, polyvinyl butyral resin is preferred as a binder when an imidazole perylene compound is used as CGM, and a polysilicone resin and a polyvinyl butyral resin, or a mixture of both are preferred as binders when TiOPc is used. No.

The charge transport layer (CTL) is composed of a charge transport material (CTM) alone or together with a binder resin. Examples of the CTM include carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline derivatives, and oxazolone. Derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives,
Phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, but are not limited thereto. Not necessarily. These may be used alone or in combination of two or more.

As the binder resin usable for the charge transport layer, for example, a polycarbonate resin, a polyacrylate resin, a polyester resin, a polystyrene resin,
Examples thereof include, but are not limited to, styrene-acrylonitrile copolymer resin, polymethacrylate resin, and styrene-methacrylate copolymer resin.

Further, in order to reduce the fatigue deterioration upon repeated use or to improve the durability, each of the layers of the photoreceptor is provided with a conventionally known antioxidant, ultraviolet absorber, electron-accepting substance and surface. An environment-dependent reducing agent such as a modifier and a plasticizer can be added in an appropriate amount as needed.

Further, in order to improve the durability, a non-photosensitive layer such as a protective layer may be provided in addition to the photosensitive layer, if necessary.

For the substrate, more preferable physical properties can be realized by mixing and using a conductivity-imparting agent, a coloring agent and the like with a polymerizable liquid material.

Next, an image forming process and each mechanism of the color image forming apparatus according to one embodiment of the present invention will be described. FIG. 3 is a sectional view of a color image forming apparatus showing an embodiment of the present invention, and FIG. 4 is a sectional view of a drum-shaped image forming body.

The color image forming apparatus according to the present embodiment uses a photosensitive drum in which a conductive layer and a photosensitive layer are provided on the outer peripheral surface of a translucent resin substrate as a drum-shaped image forming body. However, the image exposure means is disposed inside, and the image forming process means such as a charging means, a developing means, a transfer unit, a static eliminator, and a cleaning device are disposed outside.

Photosensitive drum 10 as a drum-shaped image forming body
For example, as shown in FIG. 4, a cylindrical translucent resin substrate 101 formed of a transparent member of a transparent acrylic resin is provided inside, and a transparent conductive layer 102 and an organic photoconductor layer (O
(PC) 103 is formed on the outer periphery of the base, and is rotated clockwise as indicated by an arrow in FIG. 3 in a grounded state.

In the present embodiment, it is sufficient that the photoconductive layer of the photosensitive drum has an exposure light amount capable of giving an appropriate contrast. Therefore, the light transmittance of the resin substrate of the photoreceptor drum in the present embodiment does not need to be 100%, and may be such that a certain amount of light is absorbed when the exposure beam is transmitted. As the material of the translucent substrate, an acrylic resin, particularly one polymerized using methyl methacrylate monomer, has transparency, strength, accuracy,
Fluorine, polyester, polycarbonate, polyethylene terephthalate, etc. used for other general optical members, etc.
Various translucent resins, such as, for example, can be used. Further, as long as it has a light-transmitting property with respect to the exposure light, it may be colored. The refractive index of these resins is approximately 1.5.

Examples of the method for forming the light-transmitting conductive layer include a vacuum deposition method, an active reaction deposition method, various sputtering methods, and various CV methods.
Using method D, indium tin oxide (ITO),
A thin film made of alumina, tin oxide, lead oxide, indium oxide, copper iodide, or a light-transmitting thin film made of Au, Ag, Ni, Al, or the like is used. For example, a conductive resin including metal fine particles and a binder resin is used. Various organic photoconductor layers (OPC) can be used as the photoconductor layer.

The scorotron charger 11 serving as a charging means is used for image forming processes of yellow (Y), magenta (M), cyan (C) and black (K). A charging action is performed on the layer by a control grid maintained at a predetermined potential and corona discharge by a discharge electrode, and a uniform potential is applied to the photosensitive drum 10.

The exposure unit 12 as an image exposure unit for each color is a line in which a plurality of LEDs (light emitting diodes) as light emitting elements arranged in the main scanning direction in parallel with the axis of the photosensitive drum 10 are arranged. Exposure element 12a and Selfoc lens 12b as an equal magnification imaging element are configured as a unit attached to a holder.

The exposure unit 12 for each color is integrally mounted on a holding member 20 for holding the exposure unit 12 provided in the photosensitive drum 10 in common, and the image of each color stored in the memory is provided. Data is sequentially read from the memory and input to the exposure unit 12 for each color as an electric signal.

As the exposure element, a linear element in which a plurality of light emitting elements such as FL (phosphor light emission), EL (electroluminescence), PL (plasma discharge), and LED (light emitting diode) are arranged in an array is used. Used. The light-emitting wavelength of the light-emitting element used in this embodiment is generally 600 to 900 nm, which is high in transmittance of Y, M, and C toners.
Is preferable, but since the image exposure is performed from the back surface, the wavelength is not limited to the above-mentioned wavelength, and may be a shorter wavelength at which the color toner does not have sufficient transparency.

The developing device 13 as a developing means for each color contains a one-component or two-component developer of yellow (Y), magenta (M), cyan (C) and black (K), respectively. A developing sleeve 131 that rotates in the same direction as the rotation direction of the photosensitive drum 10 at a developing position while keeping a predetermined gap from the peripheral surface of the body drum 10 is provided.

The developing unit 13 converts the electrostatic latent image formed on the photosensitive drum 10 by the charging by the scorotron charger 11 and the image exposure by the exposure unit 12 by a non-contact developing method by applying a developing bias voltage. Reversal development is performed in a non-contact state.

The original image is obtained by temporarily storing an image read by an image sensor of an image reading apparatus separate from the apparatus or an image edited by a computer as image data for each of Y, M, C and K colors. And store it.

At the start of image recording, a photoconductor drive motor (not shown) is rotated to rotate the photoconductor drum 10 clockwise as indicated by an arrow in FIG. The application of a potential to the photosensitive drum 10 is started by the charging action of the scorotron charger 11.

After the photosensitive drum 10 is applied with a potential, a first color signal, that is, Y
Exposure by an electric signal corresponding to the image data is started, and an electrostatic latent image corresponding to the Y image of the original image is formed on the photosensitive layer on the surface by rotating and scanning the drum.

The latent image is reversal-developed by the Y developing device 13 in a state where the developer on the developing sleeve 131 is not contacted, and a yellow (Y) toner image is formed in accordance with the rotation of the photosensitive drum 10.

Next, a potential is applied to the photosensitive drum 10 by the charging action of the magenta (M) scorotron charger 11 disposed above the photosensitive drum 10 on the yellow (Y) toner image. Exposure unit 12
Is exposed by an electric signal corresponding to the second color signal, i.e., the image data of M, and the magenta (M) is formed on the yellow (Y) toner image by the non-contact reversal development by the M developing unit 13. Are sequentially superimposed and formed.

The scorotron charger 1 for cyan (C) disposed on the photosensitive drum 10 by the same process.
The cyan (C) toner image corresponding to the third color signal is further provided by the exposure unit 12 for C and the developing unit 13 for C, and black (K ) Scorotron charger 11, exposure unit 1
A black (K) toner image corresponding to the fourth color signal is sequentially superimposed and formed by the second and developing units 13, and a color toner image is formed on the peripheral surface within one rotation of the photosensitive drum 10. You.

Exposure unit 1 for Y, M, C and K
Exposure of the organic photoreceptor layer of the photoreceptor drum 10 by 2 is performed from the inside of the drum through the aforementioned translucent substrate. Therefore, the exposure of the images corresponding to the second, third, and fourth color signals is performed without any influence from the previously formed toner image, and is equivalent to the image corresponding to the first color signal. It is possible to form an electrostatic latent image.

The developing unit 13 is connected to the photosensitive drum 10 with a predetermined value, for example, 100 μm to 100
In the developing operation of the developing device 13 for each color, a developing bias to which a direct current or a further alternating current is applied is applied to the developing sleeve 131, so that one component or Non-contact development with a two-component developer is performed.

The transfer paper P, which is a transfer material, is sent out from the paper supply cassette 15 which is a transfer material storage means, and is conveyed to the timing roller 16. The color toner image formed on the peripheral surface of the photoconductor drum 10 is transferred to the photoconductor drum 10 by the driving of the timing roller 16 in the transfer device 14a.
The image is transferred to a transfer sheet P fed in synchronization with the upper toner image.

The transfer paper P to which the toner image has been transferred is discharged from the drum peripheral surface by the static eliminator 14b and separated from the drum peripheral surface, and then conveyed to the fixing device 17 by a conveying belt 14e as a conveying means. After being heated and pressed in the fixing device 17 to fuse and fix the toner on the transfer paper P, the toner is discharged from the fixing device 17, conveyed by a pair of discharge conveyance rollers 18 a, and is transferred to the upper tray of the apparatus via the discharge rollers 18. Is discharged with the toner image surface facing down.

On the other hand, the photosensitive drum 10 from which the transfer paper is separated
In the cleaning device 19, the surface of the photosensitive drum 10 is rubbed by the cleaning blade 19a by the cleaning blade 19a to remove and clean the residual toner, and the toner image of the original image is continuously formed, or is temporarily stopped and the toner image of the new original image is stopped. The formation of The waste toner scraped off by the cleaning blade 19a and the cleaning roller 19b is discharged to a waste toner container (not shown) through the toner conveying screw 19c.

As shown in FIG. 5, the photosensitive drum 10 has flange members 10a and 10b at both ends for engaging and fixing the photosensitive drum.
Is rotatably supported by bearings 110a and 110b fitted into flange members 10a and 10b at both ends on a drum shaft 110 erected and fixed to the apparatus main body, and a gear G integrated with the flange member 10b is rotatably supported. The apparatus is driven at a constant speed in a predetermined direction by being driven by meshing with a drive gear on the apparatus body side.

The drum shaft 110 is integrally fixed to the inside of the photosensitive drum 10 by inserting the holding member 20 for attaching and holding the above-described exposure unit 12 for each color.

As described above, the developing devices 13 are elastically urged toward the peripheral surface of the photosensitive drum 10 from the horizontal direction, and are rotatably provided at both ends of the developing sleeves 131. By pressing the illustrated abutting roller against the non-image area of the peripheral portion of the drum, the developing sleeve 131 is pressed.
Are set at predetermined intervals. The cleaning device 19 keeps the cleaning blade 19a in pressure contact with the peripheral surface of the photosensitive drum 10 at all times, and successively removes and cleans the residual toner of the transferred toner image.

Therefore, the photosensitive drum 10 receives an external force due to the pressure contact between the developing units 13 and the cleaning device 19 even during the image exposure, and is affected by a temperature rise due to the heat generated by the light source of each exposure unit 12.

Although the color example has been described above, in the case of monochrome, contact development may be performed.

The light-transmitting substrate of the present invention is disclosed in
It is easily understood that the present invention is also applied to a system not requiring corona charging as described in Japanese Patent No. 30634.

[0078]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto.

Example 1 (Examples and Comparative Examples) Preparation of cylindrical substrate Methyl methacrylate / divinylbenzene (weight ratio 99 /
1) a polymerization initiator azobisisobutyronitrile (AIB)
N) was added thereto, and prepolymerization was performed at 40 ° C. for 1 hour to obtain a syrup-like polymerizable liquid material having a viscosity of about 100 cp. This polymerizable liquid material is supplied with an inner diameter of 100 mm and a length of 800
mm, and the entire mold is heated to 70 ° C./8 while rotating the mold and bringing it into close contact with the inner wall of the mold by centrifugal force.
The polymerization was continued at a temperature and time schedule of 80 ° C. for 8 hours and 100 ° C. for 20 hours. The obtained substrate was annealed at a cooling rate of 0.2 ° C./min to room temperature, and then removed from the mold. The end of the obtained substrate was cut to obtain a cylindrical substrate having an outer diameter of 100 mm and a length of 360 mm. This substrate was no. Let it be 1.

A coating solution composition for a conductive layer as described below was applied on the cylindrical substrate to a dry film thickness of 0.5 μm.
Heat treatment was performed at 0 ° C. for 30 minutes.

2. Conductive layer coating solution composition Conductive paint X-101H manufactured by Sumitomo Metal Mining Co., Ltd. 1000 g Toluene 1000 g The coating solution composition UCL-1 of the intermediate layer (UCL) is formed on the above substrate to a dry film thickness of 0.5 μm as follows. Was applied.

[0082] 3. UCL-1 coating solution composition Copolymer nylon resin (CM-8000, manufactured by Toray Industries, Inc.) 3 g Methanol / n-butanol = 10/1 (vol ratio) 1000 ml Coating solution composition for CGL layer as described below on UCL coated above CGL-1 was applied to a dry film thickness of 0.25 μm.

[0083] 4. CGL-1 coating solution composition Y-type titanyl phthalocyanine (CGM-1) 20 g Silicone resin (KR-5240 manufactured by Shin-Etsu Chemical Co., Ltd.) 40 g 2-butanone 1000 g (Dispersion of the above coating solution composition for 10 hours using a sand mill) ) A coating liquid composition CTL-1 of a CTL layer as described below was applied on the above-coated CGL so as to have a dry film thickness of 25 μm, and was subjected to a heat treatment at 90 ° C. for 1 hour. 1 was obtained.

[0084] 5. CTL-1 coating solution composition CTM-1 80 g Polycarbonate (Z-200 manufactured by Mitsubishi Gas Chemical Company) 120 g 1,2-dichloroethane 1000 g

[0085]

Embedded image

Comparative Example A comparative example was prepared in the same manner as in Example 1 except that divinylbenzene was not added. This comparative example substrate was N
o. 1S, and the photosensitive drum is No. 1S.

Example 2 (Example and Comparative Example) Preparation of Cylindrical Substrate A mixture of α-methylstyrene / methyl methacrylate / ethylene glycol dimethacrylate (2/8/1 part by weight) was mixed with a polymerization initiator azobisisobutyronitrile (A
IBN) was added and prepolymerization was performed at 50 ° C. for 3 hours to obtain a syrup-like polymerizable liquid material having a viscosity of about 100 cp. This polymerizable liquid material is supplied with an inner diameter of 100 mm and a length of 800
mm, and the whole mold is heated to 100 ° C. at a heating rate of 0.5 ° C./min while rotating the mold and bringing the mold into close contact with the inner wall of the mold by centrifugal force.
Was polymerized. The obtained substrate was cooled at a cooling rate of 0.2 ° C./m.
After annealing treatment to room temperature in, it was taken out of the mold. The obtained substrate was subjected to an end cutting process to obtain an outer diameter of 1 mm.
A cylindrical substrate having a length of 00 mm and a length of 360 mm was obtained.

A coating solution composition for a conductive layer was applied on the cylindrical substrate as described below to a dry film thickness of 0.5 μm.
Heat treatment was performed at 0 ° C. for 30 minutes.

2. Conductive layer coating solution composition Sumitomo Metal Mining Co., Ltd. conductive coating material X-101H 1000 g Toluene 1000 g On the above substrate, the coating solution composition UCL-2 of the intermediate layer (UCL) as described below has a dry film thickness of 1.0 μm. Was applied.

3. UCL-2 coating solution composition Titanium chelate compound TC-750 (Matsumoto Pharmaceutical Co., Ltd.) 200 g Silane coupling agent KBM-503 (Shin-Etsu Chemical Co., Ltd.) 130 g 2-propanol 1000 g The coating liquid composition CGL-1 was applied to a dry film thickness of 0.25 μm.

[0091] 4. CGL-1 coating solution composition Y-type titanyl phthalocyanine (CGM-1) 20 g Silicone resin (KR-5240 manufactured by Shin-Etsu Chemical Co., Ltd.) 40 g 2-butanone 1000 g (The above coating solution composition is dispersed for 10 hours using a sand mill) A coating liquid composition CTL-1 of a CTL layer as described below was applied on the CGL to a dry film thickness of 25 μm, and heat-treated at 90 ° C. for 1 hour. 2 was obtained.

[0092] 5. CTL-1 coating solution composition CTM-1 80 g Polycarbonate (Z-200 manufactured by Mitsubishi Gas Chemical Company) 120 g 1,2-dichloroethane 1000 g Comparative Example Comparative Example Same as Example 2 except that ethylene glycol dimethacrylate was not added as a photoreceptor. I went to. This comparative example substrate was designated No. 2S, the obtained photosensitive drum was designated No. 2
S.

Table 1 shows the measurement results of the thermal fluctuation rate of the above substrate. The measuring method was such that the photoreceptor was left in a drum storage warehouse at 23 ° C. for 3 months, aged in a constant temperature room at 20 ° C. for 24 hours, and then measured for roundness m and cylindricity n of the photoreceptor surface. Next, the photoreceptor measured as described above is placed on a stationary drum made of polyamide and placed under an air flow of 1 to 10 m / sec.
It was left standing in a constant temperature room at 110 ° C. for 1 hour.
Thereafter, the photoreceptor was left to stand in a constant temperature room at 20 ° C. for 24 hours, and the circularity Y and cylindricity Z of the surface of the photoreceptor were measured. Heat fluctuation rate S1, S
2 is calculated by the following equation.

S1 = (Y−m) / m × 100 S2 = (Zn) / n × 100

[0095]

[Table 1]

1. Actual Photographic Test An electrophotographic internal exposure type image forming apparatus having the structure shown in FIG. 1, No. 1S,
No. 2, No. 50,000 sheets of images were displayed with 2S attached.

The results were evaluated by visual evaluation and image density measurement with a Macbeth densitometer. The evaluation criteria are shown below.

Fog: Judgment based on white background density (WD) “○” WD ≦ 0.005 “Δ” 0.005 <WD ≦ 0.01 “×” 0.01 <WD Image blur: Judgment by fine line reproducibility ○: 8 lines / mm or more “Δ”: 5.6 lines / mm or more, 7.1 lines / mm or less “×” 5 lines / mm or less Density unevenness: Density difference of entire halftone (density 0.2) image ( ΔHD = maximum density−minimum density) Judgment “≦” ΔHD ≦ 0.05 “△” 0.05 <ΔHD ≦ 0.1 “×” 0.1 <ΔHD Practical application is possible.

Table 2 shows the results.

[0100]

[Table 2]

It can be seen that the photoreceptor of the present invention has no occurrence of surface distortion of the substrate, and therefore has no fog, non-uniform density and no image blur, and a stable image can be obtained.

[0102]

According to the present invention, a photoreceptor having high dimensional stability of a photoreceptor even when used at a high temperature for a long period of time and having good image characteristics when used repeatedly, a color image forming method using the same, and an image forming method using the same. Equipment can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing steps of a method for producing a translucent resin substrate of an electrophotographic photosensitive member according to the present invention.

FIG. 2 is a cross-sectional view illustrating an example of a manufacturing apparatus.

FIG. 3 is a cross-sectional configuration diagram of a color image forming apparatus showing one embodiment of the present invention.

FIG. 4 is a cross-sectional view of a drum-shaped photoconductor.

FIG. 5 is a side sectional view of a main part of FIG. 3;

[Explanation of symbols]

 Reference Signs List 10 photoreceptor drum 12 exposure unit 12a exposure element 12b selfoc lens 20 holding member 101 translucent resin base

Claims (7)

[Claims] 1. An electrophotographic photoreceptor comprising a conductive layer and a photosensitive layer provided on a light-transmitting substrate, wherein the photoreceptors represented by the following formulas have heat fluctuation rates S1 and S2 of 100 or less;
Is 80 μm or less. S1 = (Y−m) / m × 100 S2 = (Z−n) / n × 100 where, Y: roundness based on the surface of the photoconductor when stored at 110 ° C. for 1 hour with the photoconductor upright m: Roundness based on the surface of the photoconductor when stored at 20 ° C. for 24 hours with the photoconductor standing Z: Cylinder based on the surface of the photoconductor when stored at 110 ° C. with the photoconductor standing for 1 hr Degree n: Cylindricity based on the surface of the photoconductor when stored at 20 ° C. for 24 hours with the photoconductor upright 2. The electrophotographic photosensitive member according to claim 1, which is an electrophotographic photosensitive member for internal exposure. 3. The electrophotographic photoreceptor according to claim 1, wherein the translucent substrate is a resin synthesized from a vinyl monomer. 4. The electrophotographic photosensitive member according to claim 1, wherein the translucent substrate is made of a crosslinkable synthetic resin. 5. The electrophotographic photosensitive member according to claim 1, wherein the translucent substrate is made of a resin synthesized by a centrifugal polymerization method. 6. A method for uniformly charging the surface of an electrophotographic photoreceptor, repeatedly performing image exposure and color development to form a multicolor superimposed image, and performing image transfer through batch transfer, separation, fixing, and photoreceptor cleaning steps. An image forming apparatus for forming an image by using the photoreceptor according to claim 1 as an electrophotographic photoreceptor, transmitting an image through a translucent substrate, and forming an image by non-contact development. . 7. A process for uniformly charging the surface of an electrophotographic photoreceptor, an image exposing step, and a color developing step to form a multicolor superimposed image, a batch transfer step, a separating step, a fixing step, and a photoreceptor. In an image forming method which goes through each step of cleaning, the image bearing member is formed by using the photoreceptor according to claim 1 as an electrophotographic photoreceptor, exposing the image through a translucent substrate, and performing non-contact development. Image forming method.