JP2005221557A - Electrophotographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic device that will not generate the problem wherein the density difference due to defects, such as stripes and local cut unevenness (pattern cut) on an output image, even in the electrophotographic device adopting a specific injection electrification method. <P>SOLUTION: A second exposure means different from an exposure means exists between a transfer means and an electrification means. When bright part potential of the surface of an electrophotographic photoreceptor, after being exposed by the exposure means, is V<SB>L</SB>[V], V<SB>L</SB>[V] is -100[V] or smaller. The second exposure means is a means for performing an exposure in which the bright part potential of the surface of the electrophotographic photoreceptor after the second exposure is V<SB>L</SB>+60[V] to -40[V]. The film thickness d<SB>I</SB>[μm] of a charge implanting layer of the electrophotographic photoreceptor and the plastic deformation hardness H<SB>plast</SB>[N/mm<SP>2</SP>] of the surface of the electrophotographic photoreceptor satisfy a specific relationship, and the elastic deformation rate We%[%] of the surface of the electrophotographic photoreceptor, measured under an environment of 22°C/57%RH, is 40[%] to 55[%]. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic apparatus.

  An injection charging method is known as one of methods for charging the surface of an electrophotographic photosensitive member in an electrophotographic apparatus (Japanese Patent Laid-Open No. 06-003921: Patent Document 1).

  The injection charging method is a charging method in which the voltage applied to the charged particle carrier during charging is substantially equal to the dark portion potential on the surface of the electrophotographic photosensitive member after charging, that is, it does not depend on discharge. This is because if the charging method depends on discharge, the voltage applied to the charged particle carrier during charging is higher than the dark potential on the surface of the electrophotographic photosensitive member after charging by the amount corresponding to the discharge start voltage. It is.

  As described above, the injection charging method is a charging method that does not depend on discharge, and generation of ozone, nitrogen oxides, and the like is suppressed as compared with a corona charging method with discharge and a contact charging method using a charging roller. Further, there is an advantage that blurring of an output image caused by charging products generated by ozone, nitrogen oxide or the like adhering to the surface of the electrophotographic photosensitive member can be suppressed.

  Moreover, in the injection charging method, the charging stability is further improved by setting the voltage applied to the charged particle carrier during charging to a voltage obtained by superimposing an alternating current voltage on a direct current voltage instead of a direct current voltage. It has been known.

  As an injection charging method, first, an injection charging method using a magnetic brush is cited (Japanese Patent No. 2862450: Patent Document 2).

  The injection charging method using a magnetic brush magnetically constrains conductive magnetic particles with a magnetic roller, forms the conductive magnetic particles in a brush shape, and contacts the so-called magnetic brush with the surface of the electrophotographic photosensitive member. In this method, the surface of the electrophotographic photosensitive member is charged by injecting charges into the surface layer (charge injection layer) of the electrophotographic photosensitive member with a brush.

  As the conductive magnetic particles constituting the magnetic brush, particles having a particle size of about 5 [μm] to 50 [μm] are used. A sufficient speed difference is set between the magnetic brush and the surface of the electrophotographic photosensitive member.

  However, the injection charging method using a magnetic brush has a problem that the device configuration becomes complicated and the conductive magnetic particles constituting the magnetic brush fall off. If the conductive magnetic particles fall off and adhere to the surface of the electrophotographic photosensitive member, a developing bias leak or a developing failure may occur, or the output image may be fogged.

  As another injection charging method, charged particles (mainly composed of conductive particles having a particle size of 10 [nm] to 10 [μm]) in contact with an electrophotographic photosensitive member having a charge injection layer as a surface layer, and this charging By using a charging means having a charged particle carrier for supporting particles (the surface has elasticity and conductivity) and injecting charges into the charge injection layer of the electrophotographic photosensitive member by the charged particles A method of charging the surface of an electrophotographic photosensitive member is mentioned (Japanese Patent Laid-Open No. 2002-132017: Patent Document 3).

This injection charging method has an advantage that the device configuration is simpler than the injection charging method using a magnetic brush. Even when a toner recycling configuration in which the charged particles are mixed with the toner is employed, the toner recovery and toner charge normalization can be performed more stably.
Japanese Patent Laid-Open No. 06-003921 Japanese Patent No. 2862450 JP 2002-132017 A

  In the case of the charging method described in the above-mentioned JP-A-2002-132017 (Patent Document 3), in particular, charged particles are stored together with toner in the developing unit, and a part of the charged particles stored in the developing unit is stored. At the time of development by the developing means, the toner particles are transferred from the developing means to the surface of the electrophotographic photosensitive member, and some of the charged particles transferred to the surface of the electrophotographic photosensitive member are not transferred to the transfer material (paper or the like) when transferred by the transferring means. The charged particle carrier is left on the surface of the photographic photosensitive member, and a part of the charged particles remaining on the surface of the electrophotographic photosensitive member is transferred from the surface of the electrophotographic photosensitive member to the charged particle carrier during charging by the charging means. When the charged particles are supplied to the surface of the electrophotographic photosensitive member, the charged particles are transferred from the developing means to the surface of the electrophotographic photosensitive member almost at the portion developed by the toner. Happen Te.

  In addition, when the surface of the electrophotographic photosensitive member is charged by the charged particles carried on the charged particle carrier, the surface of the electrophotographic photosensitive member is rubbed by the charged particles, so that the surface of the electrophotographic photosensitive member is scratched. Or the surface of the electrophotographic photosensitive member is scraped off.

  Among the output images of the electrophotographic apparatus, particularly in the case of images such as graphs and tables, there are many portions on the surface of the electrophotographic photosensitive member that are repeatedly developed and portions that are not repeatedly developed. The part that is repeatedly developed is more rubbed than the part that is not repeatedly developed, so scratches are likely to occur or a large amount of scraping occurs, resulting in streaks on the output image. In other words, there is a problem of density difference due to defects and local shaving unevenness (pattern shaving).

  An object of the present invention is to provide charged particles (mainly composed of conductive particles having a particle size of 10 [nm] to 10 [μm]) in contact with an electrophotographic photoreceptor having a charge injection layer as a surface layer, and the charged particles. By using a charging means having a charged particle carrier for carrying (the surface has elasticity and conductivity), an electric charge is injected into the charge injection layer of the electrophotographic photosensitive member by the charged particles, and electrophotography Even if an electrophotographic apparatus adopts a method for charging the surface of a photoconductor, an electrophotographic apparatus that does not suffer from a problem of density difference due to defects such as streaks or local shaving unevenness (pattern shaving) on an output image. It is to provide.

The present invention includes an electrophotographic photosensitive member having a photosensitive layer and a charge injection layer in this order on a support, and a charging unit, an exposing unit, a developing unit, and a transferring unit are arranged in this order around the electrophotographic photosensitive member. An electrophotographic apparatus comprising: the charging means having a charged particle contacting the electrophotographic photosensitive member and a charged particle supporting member for supporting the charged particle, the surface of the charged particle supporting member being elastic and conductive. The charged particles are particles mainly composed of conductive particles having a particle size of 10 [nm] to 10 [μm], and the charging means is formed of the electrophotographic photosensitive member by the charged particles. In the electrophotographic apparatus which is a means for charging the surface of the electrophotographic photosensitive member by injecting electric charge into the charge injection layer,
Between the transfer means and the charging means, there is a second exposure means different from the exposure means,
When the bright portion potential on the surface of the electrophotographic photosensitive member after being exposed by the exposure means is V _L [V], V _L [V] is −100 [V] or less, and the second exposure means A means for performing exposure such that the bright portion potential of the surface of the electrophotographic photosensitive member after the second exposure is V _L +60 [V] to −40 [V];
The film thickness of the charge injection layer of the electrophotographic photosensitive member is d _I [μm], and the plastic deformation hardness value H _plast [N / mm ² ] of the surface of the electrophotographic photosensitive member is expressed by the following formula (1). Meet the relationship indicated,

The electrophotographic apparatus is characterized in that the elastic deformation ratio We% [%] of the surface of the electrophotographic photosensitive member measured in a 22 ° C./57% RH environment is 40 [%] to 55 [%]. .

  According to the present invention, charged particles (mainly composed of conductive particles having a particle size of 10 [nm] to 10 [μm]) in contact with an electrophotographic photosensitive member having a charge injection layer as a surface layer, and the charged particles By using a charging means having a charged particle carrier for carrying (the surface has elasticity and conductivity), an electric charge is injected into the charge injection layer of the electrophotographic photosensitive member by the charged particles, and electrophotography Even if an electrophotographic apparatus adopts a method for charging the surface of a photoconductor, an electrophotographic apparatus that does not suffer from a problem of density difference due to defects such as streaks or local shaving unevenness (pattern shaving) on an output image. Can be provided.

  Hereinafter, the present invention will be described in more detail.

  The charged particles are stored together with the toner in the developing means, and a part of the charged particles stored in the developing means is transferred from the developing means to the surface of the electrophotographic photosensitive member during the development by the developing means, and is transferred to the surface of the electrophotographic photosensitive member. Some of the transferred charged particles remain on the surface of the electrophotographic photosensitive member without being transferred to the transfer material when transferred by the transfer unit, and some of the charged particles remaining on the surface of the electrophotographic photosensitive member are charged when charged by the charging unit. When the charged particles are supplied to the charged particle carrier by transferring from the surface of the electrophotographic photosensitive member to the charged particle carrier, the smaller the amount of charged particles transferred to the transfer material during transfer, the better On the other hand, the larger the amount of charged particles remaining on the surface of the electrophotographic photosensitive member, the better.

  The charged particles may be negatively charged or positively charged. For example, in the case of a negatively charged / reversal development system, a negatively charged toner is preferably used. From the viewpoints of retention in the developing means and supply from the surface of the electrophotographic photosensitive member to the charged particle carrier, the charged particles are preferably positively charged. If the toner is negatively charged / reversed development system, the toner is negatively charged, and the charged particles are also negatively charged, most of the charged particles at the time of development are bright on the surface of the electrophotographic photosensitive member. It is transferred to the potential portion and transferred to the transfer material together with the toner during transfer. On the other hand, in the case of a negatively charged / reversal developing system in which the toner is negatively charged and the charged particles are positively charged, a part of the charged particles during development is a dark portion on the surface of the electrophotographic photosensitive member. Although it is transferred to the potential portion, most of the toner is transferred to the bright portion potential portion on the surface of the electrophotographic photosensitive member while being electrically attached to the negative toner, and the toner is transferred to the transfer material at the time of transfer. Most of it remains on the surface of the electrophotographic photosensitive member.

  As described above, as a method of charging the surface of the electrophotographic photosensitive member, charged particles that contact the electrophotographic photosensitive member having a charge injection layer as a surface layer (conductive particles having a particle size of 10 [nm] to 10 [μm]) Is used as a main component) and a charging means having a charged particle carrier (the surface has elasticity and conductivity) for supporting the charged particles, and the charged particles in the electrophotographic photosensitive member are injected by the charged particles. When a method of charging the surface of the electrophotographic photosensitive member by injecting a charge into the layer (hereinafter also referred to as a specific injection charging method) is adopted, the electrophotographic photosensitive member is charged by the charged particles carried on the charged particle carrier. When the surface is charged or when charged particles are supplied to the charged particle carrier, the surface of the electrophotographic photosensitive member is rubbed by the charged particles, so that the surface of the electrophotographic photosensitive member may be scratched. , Electronic copy The surface of the photosensitive member resulting in or scraped. In particular, when the output image is often an image such as a graph or table, there are many portions on the surface of the electrophotographic photosensitive member that are repeatedly developed and portions that are not repeatedly developed. Because it causes more rubbing damage than the part that is not repeatedly developed, scratches are likely to occur or it is partially scraped off, resulting in defects such as streaks on the output image and local A problem of density difference due to shaving unevenness (pattern shaving) occurs.

  The present inventors have found that installing the second exposure means (second exposure means) between the transfer means and the charging means is effective in solving the above problem.

However, depending on the exposure amount (second exposure amount) of the second exposure means, there are cases where there is an effect and there is no effect, and another adverse effect may occur. That is, if the second exposure amount is too small, the effect tends to be lost, and if it is too large, a negative ghost tends to occur. Strictly speaking, if the surface potential of the electrophotographic photosensitive member after exposure by the second exposure means (second exposure) is too small, there is no effect, and if it is too large, negative ghost is generated. Specifically, if the bright portion potential on the surface of the electrophotographic photosensitive member after the second exposure is less than V _L +60 [V], there is no effect, and if it exceeds −40 [V], a negative ghost is generated (this V _L [V] ≦ −100 [V]). Here, V _L is the bright portion potential [V] of the surface of the electrophotographic photosensitive member after being exposed by the exposure unit between the charging unit and the developing unit.

As long as the bright portion potential on the surface of the electrophotographic photosensitive member after the second exposure by the second exposure means is V _L +60 [V] to −40 [V], the following effect can be obtained without any adverse effect. I think so. That is,
1. After charging by the charging unit, an electrostatic latent image is formed by exposure by the exposure unit.
2. The electrostatic latent image is developed by the developing means, and the charged particles are transferred together with the toner from the developing means to the portion exposed by the exposing means.
3. Most of the developed toner is transferred to a transfer material such as paper.
4). Second exposure is performed around the charged particles and toner remaining on the surface of the electrophotographic photosensitive member, and the undeveloped portion has a lower potential than the developed portion.
5). Charged particles and toner remaining on the surface of the electrophotographic photosensitive member are transferred to the undeveloped portion by a potential difference (scattering effect).
6). Local scratches and abrasions on the surface of the electrophotographic photosensitive member are eliminated.
That's it. The potential after the second exposure effective for obtaining the “scattering effect” is the bright portion potential V _{L on} the surface of the electrophotographic photosensitive member after being exposed by the exposure means between the charging means and the developing means. Also affected by [V].

A more preferable range of the bright portion potential on the surface of the electrophotographic photosensitive member after the second exposure by the second exposure means is V _L +80 [V] to −50 [V] (at this time, V _L [V] ≦ −130 [V]).

Further, in order to sufficiently obtain the above effect, it is not sufficient that the bright portion potential on the surface of the electrophotographic photosensitive member after the second exposure is in the above range, and the film thickness of the charge injection layer of the electrophotographic photosensitive member is insufficient. D _I [μm] and the plastic deformation hardness value H _plast [N / mm ² ] of the surface of the electrophotographic photosensitive member must satisfy the relationship represented by the following formula (1):

In addition, the elastic deformation rate We% [%] of the surface of the electrophotographic photosensitive member measured in a 22 ° C./57% RH environment should be 40 [%] to 55 [%].

  Hereinafter, the plastic deformation hardness value Hplast and the elastic deformation rate We% will be described.

In the present invention, the plastic deformation hardness value H _plast and the elastic deformation rate We% were measured using a hardness meter H100VP-HCU manufactured by Fischer, Germany. Hereinafter, this is simply referred to as a Fisher hardness meter.

  The measurement environment was all 22 ° C./57% RH environment. The measurement method using a Fischer hardness tester is not a method of pressing the indenter into the sample surface and measuring the residual indentation after unloading with a microscope to obtain the hardness, as in the micro Vickers method, but applying a continuous load to the indenter. In this method, the indentation depth under load is directly read to obtain continuous hardness.

The measurement of the plastic deformation hardness value H _plast and the elastic deformation rate We% was performed as follows.

  Apply a load with a diamond indenter with a square pyramid with a face-to-face angle of 136 ° and push it to the surface of the electrophotographic photosensitive member to 1 μm. Then, reduce the load and reduce the load until the load becomes zero. taking measurement.

An example when measured with a Fischer hardness tester is shown in FIG. In FIG. 1, point A is a measurement start point. A curve AB is a curve corresponding to indentation of the indenter. Point B is a point when the maximum set indentation depth is reached, and the universal hardness value HU is a value obtained by dividing the load at point B by the surface area of the indentation generated at that time. A curve BC is a curve corresponding to “return” after the indenter is pushed in, and corresponds to the elasticity of the measurement sample. In the curve BC, when a straight line passing through two points corresponding to 95% and 60% of the maximum load is drawn, the slope becomes the Young's modulus E empirically. If the intersection of the straight line and the X axis is hr ′, the hardness value at the indentation depth hr ′ is the plastic deformation hardness value H _plast . That is, the plastic deformation hardness value _H.sub.plast is shown as a plastic deformation, that is, a hardness value with scratches.

  The elastic deformation rate We% [%] has a relationship expressed by the following equation with the elastic deformation work We [nJ] and the plastic deformation work Wr [nJ] measured in an environment of 22 ° C./57% RH. is there.

  The work of elastic deformation We [nJ] is represented by the area of the region surrounded by C-B-D-C in FIG. 1, and the work of plastic deformation Wr [nJ] is AB in FIG. It is represented by the area of the region surrounded by -C-A.

  In general, elasticity is the property that an object that has been distorted (deformed) by an external force tries to restore the original strain. If the object exceeds the elastic limit, or the external force is It is the plastic deformation that remains as part of the strain after removal. That is, the larger the value of the elastic deformation rate We%, the larger the elastic deformation, and the smaller the value of the elastic deformation rate We%, the smaller the plastic deformation.

Respect plastic deformation hardness value ^{_{H plast [N / mm 2]}} , is not satisfied the relationship represented by the above formula (1), the surface of the electrophotographic photosensitive member scratches or abrasions occur. Further, when the elastic deformation rate We% [%] is less than 40 [%], the charge injection layer which is the surface layer of the electrophotographic photosensitive member becomes brittle, so that the surface of the electrophotographic photosensitive member is scratched or scraped off. In addition, when the elastic deformation rate We% [%] exceeds 55 [%], the charged particles are easily embedded in the surface of the electrophotographic photosensitive member, so that the surface of the electrophotographic photosensitive member is scratched or scraped.

The film thickness of the charge injection layer of the electrophotographic photosensitive member is d _I [μm] and the plastic deformation hardness value H _plast [N / mm ² ] of the surface of the electrophotographic photosensitive member is expressed by the following formula (2). It is more preferable to satisfy the relationship.

  The elastic deformation rate We% [%] of the surface of the electrophotographic photosensitive member measured in a 22 ° C./57% RH environment is more preferably 42 [%] to 54 [%].

  Next, the configuration of the electrophotographic photosensitive member used in the present invention will be described.

  As described above, the electrophotographic photoreceptor used in the present invention is an electrophotographic photoreceptor having a photosensitive layer and a charge injection layer in this order on a support. The charge injection layer is a layer corresponding to the surface layer of the electrophotographic photosensitive member.

  The photosensitive layer is separated into a charge generating layer containing a charge generating material and a charge transporting layer containing a charge transporting material even if it is a single layer type photosensitive layer containing the charge transporting material and the charge generating material in the same layer. A laminated type (functional separation type) photosensitive layer may be used, but a laminated type photosensitive layer is preferred from the viewpoint of electrophotographic characteristics. The laminated photosensitive layer has a normal layer type photosensitive layer laminated in the order of the charge generation layer and the charge transport layer from the support side, and a reverse layer type photosensitive layer laminated in the order of the charge transport layer and the charge generation layer from the support side. However, a normal photosensitive layer is preferred from the viewpoint of electrophotographic characteristics.

  FIG. 2 shows an example of the layer structure of the electrophotographic photosensitive member of the present invention.

  In the electrophotographic photosensitive member having a layer structure shown in FIG. 2A, a photosensitive layer 204 is provided on a support 201, and a charge injection layer 205 is provided thereon as a surface layer. In addition, in the electrophotographic photosensitive member having the layer structure shown in FIG. 2B, a charge generation layer 2041 and a charge transport layer 2042 are provided in this order on a support 201, and further a charge layer as a surface layer thereon. An injection layer 205 is provided. Further, as shown in FIG. 2C, a conductive layer 202 and an intermediate layer 203 which will be described later may be provided between the support 201 and the charge generation layer 2041 (photosensitive layer).

  Hereinafter, as a preferable layer structure of the electrophotographic photoreceptor, an electrophotographic photoreceptor having a charge generation layer, a charge transport layer, and a charge injection layer in this order on a support will be described as an example.

  As a support body, what is necessary is just to have electroconductivity (conductive support body), for example, metal supports, such as aluminum, an aluminum alloy, and stainless steel, can be used. Moreover, the said metal support body and plastic support body which have the layer in which aluminum, aluminum alloy, the indium oxide tin oxide alloy etc. were formed into a film by vacuum deposition can also be used. In addition, a support in which conductive particles such as carbon black, tin oxide particles, titanium oxide particles, and silver particles are impregnated into plastic or paper together with an appropriate binder resin, or a plastic support having a conductive binder resin, etc. Can also be used. Examples of the shape of the support include a drum shape (cylindrical shape) and a belt shape.

  A conductive layer may be provided between the support and the photosensitive layer (charge generation layer) or an intermediate layer, which will be described later, for the purpose of preventing interference fringes due to scattering of laser light or the like, and for covering scratches on the support. . The conductive layer can be formed by dispersing conductive particles such as carbon black and metal particles in a binder resin. The thickness of the conductive layer is preferably 1 to 40 μm, and more preferably 2 to 20 μm.

  Further, an intermediate layer having a barrier function or an adhesive function may be provided between the support or the conductive layer and the photosensitive layer (charge generation layer). The intermediate layer is formed for the purpose of improving the adhesion of the photosensitive layer, improving the coating property, improving the charge injection property from the support, and protecting the photosensitive layer from electrical breakdown. The intermediate layer can be formed using materials such as casein, polyvinyl alcohol, ethyl cellulose, ethylene-acrylic acid copolymer, polyamide, modified polyamide, polyurethane, gelatin, and aluminum oxide. The thickness of the intermediate layer is preferably 5 μm or less, and more preferably 0.1 to 3 μm.

  A charge generation layer is provided on the support, the conductive layer, or the intermediate layer.

  Examples of the charge generation material used in the charge generation layer include azo pigments such as monoazo, disazo, and trisazo, phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine, indigo pigments such as indigo and thioindigo, perylene acid anhydride, Perylene pigments such as peryleneimide, polycyclic quinone pigments such as anthraquinone and pyrenequinone, squarylium dyes, pyrylium salts and thiapyrylium salts, triphenylmethane dyes, inorganic substances such as selenium, selenium-tellurium and amorphous silicon And quinacridone pigments, azulenium salt pigments, cyanine dyes, xanthene dyes, quinone imine dyes, styryl dyes, cadmium sulfide, and zinc oxide. These charge generation materials may be used alone or in combination of two or more.

  Examples of the binder resin used for the charge generation layer include polycarbonate resin, polyester resin, polyarylate resin, butyral resin, polystyrene resin, polyvinyl acetal resin, diallyl phthalate resin, acrylic resin, methacrylic resin, vinyl acetate resin, phenol resin, Examples include silicone resins, polysulfone resins, styrene-butadiene copolymer resins, alkyd resins, epoxy resins, urea resins, vinyl chloride-vinyl acetate copolymer resins, and the like. These can be used singly or in combination of two or more as a mixture or copolymer.

  The solvent used in the coating solution for the charge generation layer is selected from the solubility and dispersion stability of the binder resin and charge generation material used, and the organic solvents include alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogens. Hydrocarbons and aromatic compounds.

  The charge generation layer can be formed by applying and drying a charge generation layer coating solution obtained by dispersing a charge generation material together with a binder resin and a solvent. Examples of the dispersion method include a method using a homogenizer, an ultrasonic wave, a ball mill, a sand mill, an attritor, a roll mill and the like. The ratio between the charge generating material and the binder resin is preferably in the range of 1: 0.3 to 1: 4 (mass ratio).

  When applying the coating solution for the charge generation layer, for example, a coating method such as a dip coating method (a dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, or a blade coating method is used. be able to.

  The thickness of the charge generation layer is preferably 5 μm or less, and more preferably 0.05 to 3 μm.

  In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and the like can be added to the charge generation layer as necessary.

  A charge transport layer is provided on the charge generation layer.

  Examples of the charge transport material used for the charge transport layer include triarylamine compounds, hydrazone compounds, styryl compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds. These charge transport materials may be used alone or in combination of two or more.

  When the photosensitive layer is a laminated photosensitive layer, examples of the binder resin used for the charge transport layer include acrylic resin, styrene resin, polyester resin, polycarbonate resin, polyarylate resin, polysulfone resin, polyphenylene oxide resin, epoxy resin, Examples include polyurethane resins, alkyd resins, and unsaturated resins. In particular, polymethyl methacrylate resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polycarbonate resin, polyarylate resin, diallyl phthalate resin and the like are preferable. These can be used singly or in combination of two or more as a mixture or copolymer.

  The charge transport layer can be formed by applying and drying a charge transport layer coating solution obtained by dissolving a charge transport material and a binder resin in a solvent. The ratio between the charge transport material and the binder resin is preferably in the range of 2: 1 to 1: 2 (mass ratio).

  Solvents used in the charge transport layer coating solution include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, ethers such as 1,4-dioxane and tetrahydrofuran, and chlorobenzene. , Hydrocarbons substituted with halogen atoms such as chloroform and carbon tetrachloride are used.

  When applying the coating solution for the charge transport layer, for example, a coating method such as a dip coating method (dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, a blade coating method, or the like is used. be able to.

  The thickness of the charge transport layer is preferably 5 to 40 μm, and more preferably 10 to 30 μm.

  In addition, an antioxidant, an ultraviolet absorber, a plasticizer, and the like can be added to the charge transport layer as necessary.

  On the charge transport layer, a charge injection layer as a surface layer of the electrophotographic photosensitive member is provided. In general, the charge injection layer is a layer in which conductive particles are dispersed in a binder resin.

  The thickness of the charge injection layer is preferably 0.5 to 10 μm, and more preferably 1 to 7 μm.

  Examples of the conductive particles used for the charge injection layer include metal particles and metal oxide particles.

  Examples of the metal particles include particles such as aluminum, zinc, copper, chromium, nickel, silver, and stainless steel, and those obtained by depositing these metals on the surface of particles such as plastic.

  Examples of the metal oxide particles include zinc oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony and tantalum-doped tin oxide, and antimony-doped zirconium oxide. Can be mentioned.

  These particles may be used alone or in combination of two or more. When two or more types are used in combination, they may be simply mixed, or may be in the form of a solid solution or fusion.

  In the present invention, metal oxide particles are preferable from the viewpoint of the transparency of the charge injection layer.

  The average particle diameter of the conductive particles used in the present invention is preferably 0.3 μm or less, particularly 0.1 μm from the viewpoint of the transparency of the surface layer of the electrophotographic photoreceptor and the uniformity of the resistance of the surface layer. The following is more preferable.

  The binder resin used for the charge injection layer is preferably a curable resin having high hardness from the viewpoint of suppressing scratches and scraping on the surface of the electrophotographic photosensitive member. For example, phenol resin, acrylic resin, epoxy resin, siloxane resin And urethane resin. Among these, a phenol resin, an acrylic resin, an epoxy resin, and a siloxane resin are preferable, and a phenol resin is particularly preferable. Among phenolic resins, a resol type phenolic resin is preferable from the viewpoint of the stability of the charge injection layer coating solution. Among resol type phenol resins, those using monomers or oligomers synthesized using amine compounds are preferred, and those using monomers or oligomers synthesized using amine compounds other than ammonia are more preferred. . Examples of amine compounds other than ammonia include triethylamine, diethylamine, monoethylamine, trimethylamine, dimethylamine, and monomethylamine.

  The curable resin is a resin obtained by using a monomer or oligomer that is cured by heat or light. Among the curable resins, a resin obtained by using a monomer or oligomer that is cured by heat, that is, a thermosetting resin is preferable.

  When a curable resin is used as the binder resin for the charge injection layer, the charge injection layer is obtained by applying a charge injection layer coating solution obtained by dispersing conductive particles together with a binder resin monomer or oligomer and a solvent. It can be formed by curing with light or the like.

  Monomers and oligomers that are cured by heat, light, and the like are, for example, monomers and oligomers having a functional group that causes a polymerization reaction by energy such as heat and light at the ends of the monomers and oligomers. Large molecules having 2 to 20 repeating structural units are oligomers, and one molecule is a monomer.

  Examples of the functional group causing the polymerization reaction include ring-opening polymerization of a group having a carbon-carbon double bond such as acryloyl group, methacryloyl group, vinyl group, and acetophenone group, silanol group, and cyclic ether group. Groups, and those in which two or more kinds of molecules react to cause polymerization, such as phenol + formaldehyde.

  When the binder resin used for the charge injection layer is a thermosetting resin, a hot air drying furnace or the like can be used when it is cured by heat. Moreover, 100-300 degreeC is preferable and, as for the curing temperature when thermosetting, 120 to 200 degreeC is more preferable especially.

  In addition, the charge injection layer contains lubricating particles such as fluorine atom-containing resin particles, silicone particles, and alumina particles for the purpose of improving the surface releasability, water repellency, and surface lubricity of the electrophotographic photosensitive member. May be. Among the lubricating particles, fluorine atom-containing resin particles are preferable. Examples of the fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin, and these And particles such as a copolymer. Among these fluorine atom-containing resin particles, ethylene tetrafluoride resin particles and vinylidene fluoride resin particles are preferable. These lubricating particles can be used by appropriately selecting one kind or two or more kinds.

  In addition, inorganic particles such as silicone particles and alumina particles do not exhibit lubricity by themselves, but by dispersing them in the layer, the surface roughness of the charge injection layer, that is, the surface roughness of the electrophotographic photosensitive member. Increases, the number of contact points decreases with respect to the surface that contacts the surface of the electrophotographic photosensitive member, and as a result, the lubricity of the surface of the electrophotographic photosensitive member increases. In the present invention, the lubricating particles may include particles that impart lubricity to the surface of the electrophotographic photosensitive member.

  In the case where conductive particles and lubricating particles are contained in the charge injection layer, the conductive particles are preferably surface-treated with a surface treatment agent such as a fluorine atom-containing compound or a siloxane compound. By using the conductive particles surface-treated with these surface treatment agents, the dispersibility and dispersion stability of the conductive particles and the lubricating particles are improved. Examples of the fluorine atom-containing compound include a fluorine atom-containing silane coupling agent, a fluorine-modified silicone oil, and a fluorine atom-containing surfactant.

  Specific examples of the fluorine atom-containing silane coupling agent are given below.

  Specific examples of the fluorine-modified silicone oil are given below.

(In the formula (SO-1), n ^so1 and n ^so2 are each independently a positive integer.)
Specific examples of the fluorine atom-containing surfactant will be given below.

In (the formula (SA-1) ~ (SA -25), X sa _{is, -CF 3, -C 4 F 9} , .R represents a monovalent fluorocarbon groups such as -C _{8 F 17} ^sa is An alkylene group, an arylene group or an alkylene arylene group, and when there are a plurality of R ^{sa s in the} formula, they may be the same or different.)

  The surface treatment of conductive particles using a fluorine atom-containing compound is roughly classified into two methods, a wet method and a dry method. In terms of the stability of the treatment reaction, ease of handling, etc., the method is wet. The method is preferred. When conducting the surface treatment of the conductive particles by a wet method, for example, it can be performed as follows.

  That is, the conductive particles before the surface treatment and the fluorine atom-containing compound are mixed and dispersed in a solvent, and the fluorine atom-containing compound is adhered to the surface of the conductive particles. Examples of the dispersion method include a dispersion method using a ball mill, a sand mill, or the like. After dispersion of the conductive particles, the solvent is removed from the dispersion, and the fluorine atom-containing compound is fixed to the surface of the conductive particles. Moreover, you may heat-process further after this as needed. Further, a catalyst for promoting the reaction may be added to the dispersion. Furthermore, you may further grind | pulverize the electroconductive particle after surface treatment as needed.

  The ratio of the fluorine atom-containing compound to the conductive particles is preferably 1 to 65% by mass, more preferably 1 to 50% by mass, based on the total mass of the conductive particles surface-treated with the fluorine atom-containing compound.

  In addition, even if it contains the said fluorine atom containing compound not in the surface treatment agent of electroconductive particle but in a charge injection layer, the effect similar to the above can be acquired.

  In addition, by containing conductive particles surface-treated with a siloxane compound in the charge injection layer, the dispersibility and dispersion stability of the conductive particles and the lubricating particles are improved, and the environmental stability of the charge injection layer is further improved. In addition, a highly transparent charge injection layer can be obtained.

  In addition, when the binder resin used for the charge injection layer is a phenol resin, increasing the film thickness of the charge injection layer may cause streaky irregularities or cells to be formed. By containing the conductive particles in the charge injection layer, they can be suppressed.

  Specific examples of the siloxane compound are given below.

(In the above formula (SX-1), X ^sx represents a hydrogen atom or a methyl group. The plurality of X ^sx may be the same or different, but hydrogen for all of X ^sx (The atomic ratio is 0.1 to 50%, and n ^sx is a positive integer.)
The weight average molecular weight of the siloxane compound having the structure represented by the formula (SX-1) is preferably 200 to 30000.

  The surface treatment of conductive particles using a siloxane compound is roughly classified into two methods, a wet method and a dry method. In terms of the stability of the treatment reaction and ease of handling, the wet method is used. preferable. When conducting the surface treatment of the conductive particles by a wet method, for example, it can be performed as follows.

  That is, the conductive particles before the surface treatment and the siloxane compound are mixed and dispersed in a solvent, and the siloxane compound is adhered to the surface of the conductive particles. Examples of the dispersion method include a dispersion method using a ball mill, a sand mill, or the like. After dispersion of the conductive particles, the solvent is removed from the dispersion, and the siloxane compound is fixed to the surface of the conductive particles. Moreover, you may heat-process further after this as needed. When heat treatment is performed, hydrogen atoms in the Si—H bond in the siloxane compound are oxidized by oxygen in the air to form a new siloxane bond. As a result, the siloxane compound has a three-dimensional structure (network structure), and the surfaces of the conductive particles are covered with the three-dimensional structure. Further, a catalyst for promoting the reaction may be added to the dispersion. Furthermore, you may further grind | pulverize the electroconductive particle after surface treatment as needed.

  The ratio of the siloxane compound to the conductive particles is preferably 1 to 50% by mass, more preferably 3 to 40% by mass, based on the total mass of the conductive particles surface-treated with the siloxane compound.

  In addition, even if it contains the said siloxane compound in a charge injection layer instead of as a surface treatment agent for conductive particles, the same effect as described above can be obtained.

  In addition, an antioxidant, a charge transport material, and the like can be added to the charge injection layer as necessary.

  FIG. 3 shows an example of a schematic configuration of the electrophotographic apparatus of the present invention.

  In FIG. 3, reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is driven to rotate at a predetermined peripheral speed in the direction of the arrow about the shaft 2.

  The surface of the electrophotographic photosensitive member 1 that is rotationally driven has a charged particle 31, a charged particle carrier 32 that carries the charged particle 31, and a charged particle supply means 33 that supplies the charged particle 31 to the charged particle carrier 32. Exposure light output from an exposure means (first exposure means) 4 such as slit exposure or laser beam scanning exposure, which is uniformly charged to a predetermined positive or negative potential by a charging means (primary charging means) 3 having (Image exposure light) 4L is received. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the surface of the electrophotographic photosensitive member 1.

  The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed with the toner 5T of the developing means 5 to become a toner image. Next, the toner image formed and supported on the surface of the electrophotographic photoreceptor 1 is transferred from a transfer material supply means (not shown) to the electrophotographic photoreceptor 1 and the transfer means by a transfer bias from a transfer means (transfer roller or the like) 6. 6 (contact portion) is sequentially transferred onto a transfer material (paper or the like) P taken out and fed in synchronization with the rotation of the electrophotographic photosensitive member 1.

  The transfer material P that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member 1 and introduced into the fixing means 8 to receive the image fixing, and is printed out as an image formed product (print, copy). Is done.

  In the present invention, a second exposure unit 11 is provided between the transfer unit 6 and the charging unit 3. In FIG. 3, a second exposure unit 11 is provided between the cleaning unit (such as a cleaning blade) 7 provided between the transfer unit 6 and the charging unit 3 and the charging unit 3.

  The surface of the electrophotographic photosensitive member 1 after the transfer of the toner image is cleaned by the cleaning unit 7 after removal of the residual toner 5T, and then the second exposure light 11L output from the second exposure unit 11 is supplied. After receiving, it is used repeatedly for image formation.

  Among the above-described components such as the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5, the transfer unit 6 and the cleaning unit 7, a plurality of components are housed in a container and integrally combined as a process cartridge. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. In FIG. 3, the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5 and the cleaning unit 7 are integrally supported to form a cartridge, and the electrophotographic apparatus is used by using a guide unit 10 such as a rail of the electrophotographic apparatus main body. The process cartridge 9 is detachable from the main body.

  FIG. 4 shows another example of the schematic configuration of the electrophotographic apparatus of the present invention.

  In FIG. 4, reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is rotationally driven in a direction of an arrow about a shaft 2 at a predetermined peripheral speed.

  The surface of the electrophotographic photosensitive member 1 that is rotationally driven is brought to a predetermined positive or negative potential by a charging means (primary charging means) 3 ′ having a charged particle 31 and a charged particle carrier 32 for supporting the charged particle 31. Next, exposure light (image exposure light) 4L output from exposure means (first exposure means) 4 such as slit exposure or laser beam scanning exposure is received. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the surface of the electrophotographic photosensitive member 1.

  The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed with the toner 5T of the developing means 5 'to become a toner image. Next, the toner image formed and supported on the surface of the electrophotographic photoreceptor 1 is transferred from a transfer material supply means (not shown) to the electrophotographic photoreceptor 1 and the transfer means by a transfer bias from a transfer means (transfer roller or the like) 6. 6 (contact portion) is sequentially transferred onto a transfer material (paper or the like) P taken out and fed in synchronization with the rotation of the electrophotographic photosensitive member 1. In FIG. 4, the developing means 5 'stores charged particles 31 together with the toner 5T.

  The transfer material P that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member 1 and introduced into the fixing means 8 to receive the image fixing, and is printed out as an image formed product (print, copy). Is done.

  On the other hand, the charged particles 31 stored in the developing means 5 'are transferred from the developing means 5' to the surface of the electrophotographic photoreceptor 1 together with the toner 5T during development. Part of the charged particles 31 transferred to the surface of the electrophotographic photosensitive member 1 remains on the surface of the electrophotographic photosensitive member 1 without being transferred to the transfer material P during transfer, and the surface of the electrophotographic photosensitive member 1 during the next charging. Then, the charged particles 31 are transferred to the charged particle carrier 32, whereby the charged particles 31 are supplied to the charged particle carrier 32.

  After the toner image is transferred, the toner 5T which is not transferred and remains on the surface of the electrophotographic photosensitive member 1 is once recovered from the surface of the electrophotographic photosensitive member 1 to the charging means 3 'and the toner charge is normalized. Then, the toner is discharged from the charging unit 3 ′ to the surface of the electrophotographic photosensitive member 1, and then collected by the developing unit 5 ′ and repeatedly used for image formation.

  In the present invention, the second exposure means 11 is provided between the transfer means 6 and the charging means 3 '. After the toner image is transferred, the surface of the electrophotographic photoreceptor 1 is repeatedly used for image formation after receiving the second exposure light 11L output from the second exposure means 11.

  Among the above-described components such as the electrophotographic photosensitive member 1, the charging unit 3 ′, the developing unit 5 ′, and the transfer unit 6, a plurality of components are housed in a container and integrally combined as a process cartridge. May be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. In FIG. 4, the electrophotographic photosensitive member 1, the charging unit 3 ′ and the developing unit 5 ′ are integrally supported to form a cartridge, and the guide unit 10 such as a rail of the electrophotographic apparatus main body is used to mount the electrophotographic photosensitive member body. The process cartridge 9 ′ is detachable.

  Next, the charged particle carrier used in the present invention will be described taking a roller-shaped charged particle carrier as an example.

  The charged particle carrier is produced, for example, by forming an intermediate resistance layer using an elastic body such as rubber or foam on a cored bar. As a material for the intermediate resistance layer, a conductive agent, a sulfiding agent, and a foaming agent are used as necessary in addition to the elastic body. Examples of the elastic body include EPDM, urethane, NBR, silicone rubber, IR, and the like. Examples of the conductive agent include electronic conductive materials such as carbon black and metal oxides, and ion conductive materials.

  If necessary, the surface of the medium resistance layer, that is, the surface of the charged particle carrier may be polished to appropriately adjust the surface roughness of the charged particle carrier.

It is important that the charged particle carrier functions as an electrode. That is, it is necessary to have a sufficiently low resistance to charge the rotating electrophotographic photosensitive member. In order to obtain sufficient chargeability and leak resistance, the roller resistance of the charged particle carrier is preferably 10 ⁴ to 10 ⁷ Ω. In the present invention, the roller resistance of the charged particle carrier is such that 100 V is applied to the cored bar and the aluminum drum in a state where it is pressed against an aluminum drum having a diameter of 30 mm so that a load of 1 kg is applied to the cored bar of the charged particle carrier And measured.

  In addition, the charged particle carrier needs to have sufficient elasticity to obtain a sufficient contact state with the electrophotographic photosensitive member via the charged particles. If the hardness of the charged particle carrier is too low, the shape of the charged particle carrier is not stable, and the contact property tends to deteriorate. On the other hand, if the hardness of the charged particle carrier is too high, the contact portion (charging nip portion) tends not to be sufficiently secured, and the micro contact property with the surface of the electrophotographic photosensitive member tends to deteriorate. . Therefore, the Asker C hardness measured from the surface of the charged particle carrier is preferably 25 to 50 °.

  The charged particle carrier may be, for example, a roller using a fur brush in which each pile has elasticity.

  Next, the charged particles used in the present invention will be described.

  Examples of the charged particles include conductive inorganic particles such as metal oxide particles, and mixtures (composite particles) of these and organic substances.

In the electrophotographic apparatus of the present invention, since charge is transferred via charged particles during charging, the specific resistance (volume resistivity) of the charged particles is preferably 10 ¹⁰ Ω · cm or less. The specific resistance of the charged particles was measured by the tablet method and obtained by normalization. Specifically, 0.5 g of charged particles to be measured for specific resistance are placed in a cylinder with a bottom area of 2.26 cm ² , 15 kg of pressure is applied to the upper and lower electrodes, and a resistance value is applied by applying a voltage of 100 V. Was measured and then normalized to calculate the specific resistance.

  Further, the particle diameter of the charged particles is preferably 50 μm or less in order to obtain good charge uniformity. About the minimum of a particle size, 10 nm becomes a lower limit as what a particle | grain is obtained stably. In the present invention, the particle diameter in the case where the charged particles are constituted as an aggregate is defined as an average particle diameter as the aggregate. To measure the particle size of the charged particles, 100 or more samples were randomly extracted from observation with an optical microscope or electron microscope, and the volume particle size distribution was calculated with the maximum chord length in the horizontal direction, and determined with the 50% average particle size. .

  The method for measuring the charge amount of the charged particles in the present invention will be described with reference to FIG.

In a 23 ° C./60% RH environment, a mixture of 19.6 g of iron powder carrier DSP-138 and 0.4 g of conductive particles is placed in a 50-100 ml polyethylene bottle and shaken 50 times by hand. Next, 1.0 to 1.2 g of the above mixture is put into a metal measuring container 502 having a 500 mesh screen 503 at the bottom, and a metal lid 504 is formed. The mass of the entire measurement container 502 at this time is measured and is defined as W ₁ [g]. Next, in the suction machine 501 (at least the part in contact with the measurement container 502 is suctioned), the suction is performed from the suction port 507 and the air volume control valve 506 is adjusted to set the pressure of the vacuum gauge 505 to 4900 hPa. In this state, suction is performed for 1 minute to remove charged particles by suction. The potential of the electrometer 509 at this time is set to V ₁ [V]. In FIG. 5, reference numeral 508 denotes a capacitor, and the capacity is C ₁ [μF]. Further, the mass of the entire measurement container after suction is measured and is set to W ₂ [g]. The triboelectric charge amount [μC / g] of the charged particles is derived from the following equation.
Triboelectric charge [μC / g] = C ₁ × V ₁ / (W ₁ −W ₂ )

One of the measures for grasping the abundance of the charged particles on the surface of the charged particle carrier is the coverage [%]. From the viewpoint of charging uniformity, the coverage is preferably 20 to 100%. Another measure is the loading amount. The supported amount is preferably 0.1 to 100 mg / cm ² . If the amount of the charged particles existing on the surface of the charged particle carrier is too small, the chargeability and the charge uniformity may be lowered. The amount of the charged particles existing on the surface of the charged particle carrier may be adjusted by controlling the amount of charged particles supplied to the charged particle carrier, and a contact member such as an elastic blade is applied to the charged particle carrier. It can also be adjusted by touching. In particular, when a toner recycling configuration is adopted, the contact member such as an elastic blade is also effective in normalizing the toner charge.

The resistance of the toner is preferably 10 ¹³ Ω · cm or more in volume resistivity from the viewpoint of maintaining the charge due to frictional charging on the surface. Therefore, particularly when the toner recycling configuration is adopted, the toner is also carried on the charged particle carrier together with the charged particles, so that the resistance of the entire powder (charged particles + toner, etc.) carried on the charged particle carrier increases. . When the resistance of the entire powder supported on the charged particle support increases, the chargeability and charge uniformity may be adversely affected. The resistance of the entire powder supported on the charged particle carrier is preferably 10 ⁻¹ to 10 ¹² Ω · cm, particularly 10 ⁻¹ to 10 ¹⁰ Ω · cm in terms of volume resistivity. Is more preferable. These resistances are measured according to the method for measuring the specific resistance of the charged particles.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to these. In the examples, “part” means “part by mass”.

(Example 1)
An aluminum cylinder having a diameter of 30 mm and a length of 260.5 mm was used as a support.

  Next, a 5% by mass methanol solution of polyamide resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) was prepared as an intermediate layer coating solution, and this intermediate layer coating solution was dip coated on the support. The film was dried with hot air at 60 ° C. for 10 minutes to form an intermediate layer having a thickness of 0.5 μm.

  Next, it has a structure represented by the following formula and has strong peaks at 9.0 °, 14.2 °, 23.9 °, and 27.1 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction. 4 parts of a crystalline form of oxytitanium phthalocyanine (charge generating material) having

2 parts of polyvinyl butyral resin (trade name: BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 80 parts of cyclohexanone are dispersed for 4 hours in a sand mill using glass beads having a diameter of 1 mm to prepare a coating solution for a charge generation layer. did.

  This charge generation layer coating solution was dip coated on the intermediate layer and dried with hot air at 90 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

  Next, 10 parts of a compound (charge transport material) having a structure represented by the following formula:

Further, 10 parts of bisphenol Z-type polycarbonate (trade name: Z-200, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was dissolved in 100 parts of monochlorobenzene to prepare a coating solution for charge transport layer.

  This charge transport layer coating solution was dip-coated on the charge generation layer and dried at 105 ° C. for 1 hour to form a charge transport layer having a thickness of 21 μm.

  Next, a surface treating agent having a structure represented by the following formula

20 parts of antimony-doped tin oxide particles surface treated with (the surface treatment agent is 7.2% by mass with respect to the antimony-doped tin oxide particles before treatment; hereinafter referred to as a treatment amount of 7.2%), methyl hydrogen Disperse 30 parts of antimony-doped tin oxide particles surface treated with silicone oil (surface treatment agent, trade name: KF99, manufactured by Shin-Etsu Silicone Co., Ltd.) and 150 parts of ethanol in a sand mill for 66 hours. Then, 20 parts of polytetrafluoroethylene particles (average particle size: 0.18 μm) were added thereto and dispersed for 2 hours to obtain a dispersion.

  A resol thermosetting phenol using a monomer / oligomer (number average molecular weight (GPC): 800) synthesized using an amine compound (triethylamine) other than ammonia as a binder resin for the charge injection layer in this dispersion. 30 parts of the resin was dissolved to prepare a charge injection layer coating solution.

  This charge injection layer coating solution was dip coated on the charge transport layer and dried in hot air at 145 ° C. for 1 hour to form a charge injection layer having a thickness of 5 μm.

  In this way, an electrophotographic photoreceptor having a charge injection layer as a surface layer was produced.

  Since the charge injection layer is a thin film, the film thickness was measured using an instantaneous multi-photometry system MCPD-2000 (manufactured by Otsuka Electronics Co., Ltd.) based on light interference. Further, the dispersibility of the charge injection layer coating solution was good, and the surface of the charge injection layer was a uniform surface without unevenness.

When the plastic deformation hardness value H _plast and the elastic deformation ratio We% of the surface of the obtained electrophotographic photosensitive member were measured as described above, the plastic deformation hardness value H _plast = 548 [N / mm ² ]. The elastic deformation ratio We% was 47.4 [%]. In addition, these measurements were performed 10 times by changing the measurement position on the same sample, and the average of 8 points excluding the maximum value and the minimum value was obtained.

  In addition, the produced electrophotographic photosensitive member is mounted on an electrophotographic apparatus (laser beam printer) manufactured by Hewlett-Packard Co., Ltd., modified laser jet 4000 (configuration shown in FIG. 3), and 12000 in a 22 ° C./57% RH environment. A sheet durability test was performed and the output image was evaluated. The evaluation results are shown in Table 1. Regarding the evaluation criteria in Table 1, A is the best in terms of black streaks, density unevenness due to shaving unevenness, and negative ghost, and then worsens in the order of B, C, D, and E.

  The details of the electrophotographic apparatus used for the evaluation of the output image of Example 1 are as follows.

  First, the charging method was modified to the specific injection charging method (the method shown in FIG. 3).

  As the charged particle carrier, a roller-shaped member in which an intermediate resistance layer using an elastic body was formed on a core metal was used. For the medium resistance layer, the material for the medium resistance layer formulated with urethane resin, carbon black (conductive particles), sulfiding agent and foaming agent was molded into a roller shape on the core metal, and then the surface was polished. . The charged particle carrier had a diameter of 12 mm, a length in the longitudinal direction of 250 mm, and a roller resistance of 100 kΩ.

As the charged particles, conductive zinc oxide particles having a specific resistance of 10 ⁶ Ω · cm and an average particle size of 3 μm were used.

  Further, as a charged particle supply means for supplying charged particles to the charged particle carrier, a regulating blade is brought into contact with the charged particle carrier and the charged particles are held between the regulating blade and the charged particle carrier. Adopted. As the charged particle carrier rotates, charged particles are supplied to the charged particle carrier.

  The charged particle carrier was rotated with a speed difference with respect to the electrophotographic photosensitive member. That is, a cylindrical electrophotographic photosensitive member having a diameter of 30 mm was rotated at a peripheral speed of 110 mm / s, and the charged particle carrier was rotated at 150 rpm.

Further, by applying a DC voltage of −550 V to the core of the charged particle carrier, the surface of the electrophotographic photosensitive member was charged (injection charging) to a potential equivalent to the applied voltage of −550 V. That is, the dark portion potential V _D = −550 [V].

The first exposure conditions were set so that the bright portion potential _VL of the surface of the electrophotographic photosensitive member after being exposed by the exposure means (first exposure means) was -150V. Further, the light potential V _L2 of the surface of the electrophotographic photosensitive member after being exposed by the second exposure means so as to be -60 V, and sets a second exposure condition. Both V _L and V _L2 were measured at the position of the developing device (when V _L2 was measured, the voltage of the charging means was turned off).

(Example 2)
In Example _1, except for changing the _{V L2} to -80 V, the same as in Example 1. The evaluation results are shown in Table 1.

(Example 3)
In Example _1, except for changing the _{V L2} to -45 V, the same as in Example 1. The evaluation results are shown in Table 1.

Example 4
In Example 1, a resol type thermosetting phenol resin using a monomer / oligomer (number average molecular weight (GPC): 400) synthesized using an amine compound (triethylamine) other than ammonia as the binder resin of the charge injection layer Example 1 is the same as Example 1 except that the electrophotographic apparatus used for the evaluation of the output image is changed to the electrophotographic apparatus having the configuration shown in FIG. The evaluation results are shown in Table 1.

  Details of the electrophotographic apparatus used for the evaluation of the output image of Example 4 are as follows.

  The charging means is not provided with charged particle supply means. Except for this point, it is the same as the charging means (charged particle carrier, charged particle) of the electrophotographic apparatus used for the evaluation of the output image of Example 1.

  The charged particles are stored together with the toner in the developing unit, and a part of the charged particles stored in the developing unit is transferred from the developing unit to the surface of the electrophotographic photosensitive member during development and transferred to the surface of the electrophotographic photosensitive member. Some charged particles remain on the surface of the electrophotographic photosensitive member without being transferred to the transfer material during transfer, and some charged particles remaining on the surface of the electrophotographic photosensitive member are charged from the surface of the electrophotographic photosensitive member during charging. By transferring to the particle carrier, the charged particles are supplied to the charged particle carrier.

  The electrophotographic apparatus used for the evaluation of the output image of Example 4 is an electrophotographic apparatus adopting a so-called toner recycling configuration. Toner remaining on the surface of the electrophotographic photosensitive member without being transferred after the toner image is transferred is temporarily collected from the surface of the electrophotographic photosensitive member to the charging unit without being cleaned by a dedicated cleaning unit to normalize the toner charge. Then, the toner is discharged from the charging unit onto the surface of the electrophotographic photosensitive member, and then collected by the developing unit and repeatedly used (reused) for image formation.

  The electrophotographic apparatus used for the evaluation of the output image of Example 4 is a negative charging / reversal development system. The toner is a one-component magnetic toner (negative toner). The charged particles are positively charged.

  Other conditions are the same as those of the electrophotographic apparatus used for the evaluation of the output image of Example 1.

(Example 5)
In Example 4, a resol-type thermosetting phenolic resin using a monomer / oligomer (number average molecular weight (GPC): 2000) synthesized using an amine compound (triethylamine) other than ammonia as the binder resin of the charge injection layer Example 4 is the same as Example 4 except that the change is made. The evaluation results are shown in Table 1.

(Example 6)
Example 4 is the same as Example 4 except that the amount of polytetrafluoroethylene particles in the charge injection layer coating solution is changed to 30 parts. The evaluation results are shown in Table 1.

(Example 7)
In Example 1, it is the same as Example 1 except having changed the amount of the resol type thermosetting phenol resin in the charge injection layer coating solution to 20 parts. The evaluation results are shown in Table 1.

(Example 8)
In Example 1, a resol-type thermosetting phenol resin using a monomer / oligomer (number average molecular weight (GPC): 100) synthesized using an amine compound (triethylamine) other than ammonia as the binder resin of the charge injection layer Except that the amount of polytetrafluoroethylene particles in the charge injection layer coating solution was changed to 25 parts, and the thickness of the charge injection layer was changed to 3 μm. The evaluation results are shown in Table 1.

Example 9
In Example 5, it changes the electrophotographic apparatus used in the evaluation of the output image in an electrophotographic apparatus used in Example 1, except for changing the V _L2 to -80 V, the same as in Example 5. The evaluation results are shown in Table 1.

(Example 10)
In Example 6, it changes the electrophotographic apparatus used in the evaluation of the output image in an electrophotographic apparatus used in Example 1, except for changing the V _L2 to -45 V, the same as in Example 6. The evaluation results are shown in Table 1.

(Example 11)
In Example _4, except for changing the _{V L2} to -45 V, the same as in Example 4. The evaluation results are shown in Table 1.

(Example 12)
In Example _7, except for changing the _{V L2} to -80 V, the same as in Example 7. The evaluation results are shown in Table 1.

(Example 13)
In Example _8, except for changing the _{V L2} to -45 V, the same as in Example 8. The evaluation results are shown in Table 1.

(Example 14)
In Example _1, except for changing the _{V L2} to -90 V, the same as in Example 1. The evaluation results are shown in Table 1.

(Example 15)
In Example _1, except for changing the _{V L2} to -40 V, the same as in Example 1. The evaluation results are shown in Table 1.

(Example 16)
In Example 4, a resol-type thermosetting phenol resin using a monomer / oligomer (number average molecular weight (GPC): 7000) synthesized using an amine compound (triethylamine) other than ammonia as the binder resin of the charge injection layer In the same manner as in Example 4 except that the temperature was changed to 125 ° C. and the time was changed to 1.5 hours at the time of hot-air drying after dip-coating the charge injection layer coating solution on the charge transport layer. . The evaluation results are shown in Table 1.

(Example 17)
In Example 1, a resol-type thermosetting phenol resin using a monomer / oligomer (number average molecular weight (GPC): 300) synthesized using an amine compound (triethylamine) other than ammonia as the binder resin of the charge injection layer Except that the amount of polytetrafluoroethylene particles in the charge injection layer coating solution was changed to 30 parts and the thickness of the charge injection layer was changed to 3 μm. The evaluation results are shown in Table 1.

(Example 18)
In Example 1, a resol-type thermosetting phenol resin using a monomer / oligomer (number average molecular weight (GPC): 5000) synthesized using an amine compound (triethylamine) other than ammonia as the binder resin of the charge injection layer. Except that the amount of polytetrafluoroethylene particles in the charge injection layer coating solution was changed to 30 parts, and the thickness of the charge injection layer was changed to 8 μm. The evaluation results are shown in Table 1.

(Comparative Example 1)
In Example _1, except for changing the _{V L2} to -100 V, the same as in Example 1. The evaluation results are shown in Table 1.

(Comparative Example 2)
In Example _1, except for changing the _{V L2} to -30 V, the same as in Example 1. The evaluation results are shown in Table 1.

(Comparative Example 3)
Example 4 is the same as Example 4 except that the charge injection layer is formed as follows. The evaluation results are shown in Table 1.

  That is, the surface treating agent having a structure represented by the following formula

20 parts of antimony-doped tin oxide particles surface treated with (the surface treatment agent is 7.2% by mass with respect to the antimony-doped tin oxide particles before treatment; hereinafter referred to as a treatment amount of 7.2%), methyl hydrogen Disperse 30 parts of antimony-doped tin oxide particles surface treated with silicone oil (surface treatment agent, trade name: KF99, manufactured by Shin-Etsu Silicone Co., Ltd.) and 150 parts of ethanol in a sand mill for 66 hours. Then, 20 parts of polytetrafluoroethylene particles (average particle size: 0.18 μm) were added thereto and dispersed for 2 hours to obtain a dispersion.

  In this dispersion, 120 parts of an acrylic resin monomer having a structure represented by the following formula as a binder resin for the charge injection layer,

Then, 7.2 parts of 2-methylthioxanthone as a photopolymerization initiator was dissolved to prepare a coating solution for a charge injection layer.

This charge injection layer coating solution is dip-coated on the charge transport layer, photocured with a high-pressure mercury lamp at a light intensity of 800 mW / cm ² for 30 seconds, and then dried with hot air at 120 ° C. for 2 hours to form a film. A charge injection layer having a thickness of 5 μm was formed.

(Comparative Example 4)
In Example 1, the surface-treated antimony-doped tin oxide particles and polytetrafluoroethylene particles were not added to the charge injection layer coating solution, and the binder resin of the charge injection layer was methylphenylpolysiloxane (trade name: KF-50500CS). : Manufactured by Shin-Etsu Silicone Co., Ltd.) and the same as Example 1 except that the temperature was changed to 155 ° C. during hot air drying after dip-coating the charge injection layer coating solution onto the charge transport layer. is there. The evaluation results are shown in Table 1.

(Comparative Example 5)
Example 1 is the same as Example 1 except that the charge injection layer is formed as follows. The evaluation results are shown in Table 1.

  That is, the surface treating agent having a structure represented by the following formula

20 parts of antimony-doped tin oxide particles surface treated with (the surface treatment agent is 7.2% by mass with respect to the antimony-doped tin oxide particles before treatment; hereinafter referred to as a treatment amount of 7.2%), methyl hydrogen Disperse 30 parts of antimony-doped tin oxide particles surface treated with silicone oil (surface treatment agent, trade name: KF99, manufactured by Shin-Etsu Silicone Co., Ltd.) and 150 parts of ethanol in a sand mill for 66 hours. Then, 20 parts of polytetrafluoroethylene particles (average particle size: 0.18 μm) were added thereto and dispersed for 2 hours to obtain a dispersion.

  In this dispersion, 80 parts of an acrylic resin monomer having a structure represented by the following formula as a binder resin for the charge injection layer,

And 6 parts of 2-methylthioxanthone was dissolved as a photopolymerization initiator to prepare a coating solution for charge injection layer.

The charge injection layer coating solution is dip coated on the charge transport layer, photocured with a high pressure mercury lamp at a light intensity of 600 mW / cm ² for 60 seconds, and then dried with hot air at 120 ° C. for 1.5 hours. A charge injection layer having a thickness of 5 μm was formed.

It is a figure which shows the example at the time of measuring with a Fisher hardness meter. It is a figure which shows the example of the layer structure of the electrophotographic photoreceptor of this invention. It is a figure which shows an example of schematic structure of the electrophotographic apparatus of this invention. It is a figure which shows another example of schematic structure of the electrophotographic apparatus of this invention. It is a figure for demonstrating the measuring method of the charge amount of a charged particle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 201 Support body 202 Conductive layer 203 Intermediate layer 204 Photosensitive layer 2041 Charge generation layer 2042 Charge transport layer 205 Charge injection layer 1 Electrophotographic photosensitive member 2 Axis 3 Charging means 3 ′ Charging means 31 Charged particles 32 Charged particle carrier 33 Charged particle supply 33 Means 4 Exposure means 4L Exposure light 5 Development means 5 ′ Development means 5T Toner 6 Transfer means 7 Cleaning means 8 Fixing means 9 Process cartridge 9 ′ Process cartridge 10 Guide means 11 Second exposure means 11L Second exposure light P Transfer material 501 Suction Machine 502 Measuring container 503 Screen 504 Lid 505 Vacuum gauge 506 Air volume control valve 507 Suction port 508 Condenser 509 Electrometer

Claims (27)

An electrophotographic apparatus having an electrophotographic photosensitive member having a photosensitive layer and a charge injection layer in this order on a support, and a charging unit, an exposing unit, a developing unit, and a transferring unit in that order around the electrophotographic photosensitive member The charging means has a charged particle contacting the electrophotographic photosensitive member and a charged particle carrier for supporting the charged particle, and the charged particle carrier has a surface having elasticity and conductivity. The charged particles are particles mainly composed of conductive particles having a particle size of 10 [nm] to 10 [μm], and the charging means is applied to the charge injection layer of the electrophotographic photosensitive member by the charged particles. In the electrophotographic apparatus which is a means for charging the surface of the electrophotographic photosensitive member by injecting electric charge,
Between the transfer means and the charging means, there is a second exposure means different from the exposure means,
When the bright portion potential on the surface of the electrophotographic photosensitive member after being exposed by the exposure means is V _L [V], V _L [V] is −100 [V] or less, and the second exposure means A means for performing exposure such that the bright portion potential of the surface of the electrophotographic photosensitive member after the second exposure is V _L +60 [V] to −40 [V];
The film thickness of the charge injection layer of the electrophotographic photosensitive member is d _I [μm], and the plastic deformation hardness value H _plast [N / mm ² ] of the surface of the electrophotographic photosensitive member is expressed by the following formula (1). Meet the relationship indicated,

An electrophotographic apparatus having an elastic deformation ratio We% [%] of a surface of the electrophotographic photosensitive member measured in a 22 ° C./57% RH environment of 40 [%] to 55 [%]. When the bright portion potential on the surface of the electrophotographic photosensitive member after being exposed by the exposure means is V _L [V], V _L [V] is −130 [V] or less, and the second exposure means 2. The electrophotographic apparatus according to claim 1, wherein the electrophotographic apparatus is a means for performing exposure such that a bright portion potential of the surface of the electrophotographic photosensitive member after the second exposure is V _L +80 [V] to −50 [V]. The film thickness of the charge injection layer of the electrophotographic photosensitive member is d _I [μm], and the plastic deformation hardness value H _plast [N / mm ² ] of the surface of the electrophotographic photosensitive member is expressed by the following formula (2). The electrophotographic apparatus according to claim 1, wherein the electrophotographic apparatus satisfies the relationship shown.

  The elastic deformation ratio We% [%] of the surface of the electrophotographic photosensitive member measured in a 22 ° C / 57% RH environment is 42 [%] to 54 [%]. Electrophotographic equipment.   The electrophotographic apparatus according to claim 1, wherein the charged particle carrier has a porous body surface. The electrophotographic apparatus according to claim 1, wherein the charged particles have a resistance of 10 ¹² [Ω · cm] to 10 ⁻¹ [Ω · cm].   The electrophotographic apparatus according to claim 1, wherein the charging unit includes a charged particle supply unit for supplying the charged particle to the charged particle carrier.   The charged particles are stored together with the toner in the developing unit, and a part of the charged particles stored in the developing unit is transferred from the developing unit to the surface of the electrophotographic photosensitive member during development by the developing unit, A part of the charged particles transferred to the surface of the electrophotographic photosensitive member remains on the surface of the electrophotographic photosensitive member without being transferred to the transfer material at the time of transfer by the transfer unit, and remains on the surface of the electrophotographic photosensitive member. The charged particles are supplied to the charged particle carrier by transferring a part of the particles from the surface of the electrophotographic photosensitive member to the charged particle carrier during charging by the charging means. The electrophotographic apparatus according to any one of the above.   The electrophotographic apparatus according to claim 1, wherein the charge injection layer of the electrophotographic photosensitive member contains lubricating particles.   The electrophotographic apparatus according to claim 9, wherein the lubricating particles are at least one kind of particles selected from the group consisting of fluorine atom-containing resin particles, silicone particles, and alumina particles.   The electrophotographic apparatus according to claim 1, wherein the charge injection layer of the electrophotographic photosensitive member contains conductive particles.   The electrophotographic apparatus according to claim 10, wherein the conductive particles contained in the charge injection layer of the electrophotographic photosensitive member are metal particles or metal oxide particles.   The electrophotographic apparatus according to claim 11 or 12, wherein the conductive particles contained in the charge injection layer of the electrophotographic photosensitive member are surface-treated with a fluorine atom-containing compound or a siloxane compound.   The electrophotographic apparatus according to claim 13, wherein the fluorine atom-containing compound is at least one selected from the group consisting of a fluorine atom-containing silane coupling agent, a fluorine-modified silicone oil, and a fluorine-based surfactant. The electrophotographic apparatus according to claim 13, wherein the siloxane compound is a siloxane compound having a structure represented by the following formula (SX-1).

(In the formula (SX-1), X ^sx represents a hydrogen atom or a methyl group. A plurality of X ^sx may be the same or different, but a hydrogen atom for all of the X ^sx Is 0.1 to 5%, and n ^sx is a positive integer.)   The electrophotographic apparatus according to claim 1, wherein the charge injection layer of the electrophotographic photosensitive member contains a curable resin as a binder resin.   The electrophotographic apparatus according to claim 16, wherein the curable resin is at least one resin selected from the group consisting of a phenol resin, an acrylic resin, an epoxy resin, and a siloxane resin.   The electrophotographic apparatus according to claim 17, wherein the phenol resin is a resol type phenol resin.   The electrophotographic apparatus according to claim 18, wherein the resol type phenolic resin is a resin using a monomer or an oligomer synthesized using an amine compound.   The electrophotographic apparatus according to claim 19, wherein the amine compound is an amine compound other than ammonia.   21. The electrophotographic apparatus according to claim 16, wherein the curable resin is a thermosetting resin.   The electrophotographic apparatus according to claim 1, wherein a voltage applied to the charged particle carrier during charging by the charging unit is a voltage of only a direct current voltage. The DC voltage (V _DC [V]), the dark portion potential (V _D [V]) on the surface of the electrophotographic photosensitive member after being charged by the charging means, and the film thickness of the photosensitive layer of the electrophotographic photosensitive member. The electrophotographic apparatus according to claim 22, wherein (d _P [μm]) and a relative dielectric constant (K _P ) of the photosensitive layer of the electrophotographic photosensitive member satisfy a relationship represented by the following formula (3).

  The electrophotographic apparatus according to claim 1, wherein the voltage applied to the charged particle carrier during charging by the charging unit is a voltage obtained by superimposing an AC voltage on a DC voltage. After being charged by the DC voltage (V _DC [V]), the AC voltage (V _AC [V]), the peak-to-peak voltage of the AC voltage (V _P-P [V]), and the charging means. The dark portion potential (V _D [V]) on the surface of the electrophotographic photosensitive member, the film thickness (d _P [μm]) of the photosensitive layer of the electrophotographic photosensitive member, and the dielectric constant of the photosensitive layer of the electrophotographic photosensitive member The electrophotographic apparatus according to claim 24, wherein the rate (K _P ) satisfies a relationship represented by the following formula (3), a relationship represented by the following formula (4), and a relationship represented by the following formula (5).

  The electrophotographic apparatus according to claim 1, wherein the charge injection layer of the electrophotographic photosensitive member has a thickness of 1 [μm] to 10 [μm].   27. The electrophotographic apparatus according to claim 1, wherein the charged particles are particles mainly composed of conductive particles having a particle size of 100 [nm] to 3 [[mu] m].

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