JPH0926671A - Electrophotographic photoreceptor, electrophotographic image forming method and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having a small diameter, used in an electrophotographic device having a developing stage using small particle size toner and a transfer stage performing transfer through a sheet, and obtaining a high-quality image without the defect of an image such as transfer unevenness and transfer middle omission; an electrophotographic image forming method and an electrophotographic device using the photoreceptor. SOLUTION: This electrophotographic photoreceptor is used in the image forming device using a photoreceptor drum whose outside diameter is <=ϕ65mm and the toner whose weight average particle size is <=8μm, and performing the transfer through the sheet whose volume resistivity is 10<10> to 10<19> Ωcm; and at least has a photoreceptive layer 27 on a conductive supporting body 21. The contact angle of the outermost layer of the photoreceptor with pure water is >=110 deg..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, an electrophotographic image forming method and an electrophotographic apparatus, and in particular, it is used in a transfer process through a sheet using a small diameter drum and a small particle diameter toner, and a transfer failure or the like occurs. The present invention relates to an electrophotographic photosensitive member, an electrophotographic image forming method, and an electrophotographic apparatus that realize a high-quality image free from defects.

[0002]

2. Description of the Related Art Conventionally, as photoconductive materials used for electrophotographic photoreceptors, inorganic materials such as zinc oxide, selenium, and cadmium sulfide have been known. Organic polyvinylcarbazole, phthalocyanine, azo pigments and the like have been widely used although their advantages such as high productivity and non-pollution have been noticed and they are inferior in photoconductive characteristics and durability. Recently, new materials are being devised in which these drawbacks have been improved, and in particular, their photoconductive properties are surpassing those of inorganic materials.

These electrophotographic photoconductors are repeatedly subjected to various actions such as charging, exposure, development, transfer, cleaning and charge removal in the electrophotographic process of copying machines, laser beam printers and the like, so that they are subjected to various chemical and physical processes. Durability is required. In particular, the surface properties such as the surface energy of the photoconductor are involved in the developer transferability on the photoconductor, stains on the photoconductor, etc., and are important factors for obtaining a high quality image.
On the other hand, the above-mentioned organic photoconductive material does not have film-forming property by itself, so that it is generally formed with a binder resin. Therefore, it is no exaggeration to say that surface properties such as surface energy are almost limited by the selection of the binder resin. However, the binder resins satisfying the photoconductive properties are quite limited, and in reality, the desired surface properties have not been obtained yet. The binder resin used in the photoreceptor using the organic photoconductor, polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, polyamide imide, polysulfone, polyallyl ether, polyacetal, Nylon, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, butyral resin and the like can be mentioned, but none of them gives a sufficiently low energy surface.

[0004]

In recent years, an electrophotographic process capable of faithfully reproducing a color image has been required, and several systems have been proposed. Among them, as shown in FIG. 1, a structure having a photosensitive drum and a transfer sheet that holds a transfer material such as a transfer paper is adopted, and three types of three primary colors or four-color images in which black is added to each of them are sequentially extracted. Generally, an apparatus adopting a transfer system that reproduces a color image by superimposing it on a transfer material is used.

One of the problems in such a process is deterioration of transfer efficiency. That is, since the toner is transferred to the transfer material via the transfer sheet, only a more indirect transfer action than usual can be given. As a result, the pre-transfer toner on the photosensitive member may not be sufficiently transferred to the transfer material side, and only a low quality image may be obtained due to transfer failure. In particular, when the above-mentioned conventional organic photoconductor is used, image defects such as uneven transfer of solid image portions and voids in transfer of character portions occur.

The deterioration of the transfer efficiency becomes remarkable when the weight average particle diameter of the toner is as small as 8 μm or less.

Further, when the outer diameter of the photoconductor drum is Φ65 mm or less, the transfer nip between the photoconductor drum and the transfer sheet becomes narrow, and the transfer efficiency becomes worse.

An object of the present invention is to improve the surface physical properties of a photoreceptor without deteriorating the electrophotographic characteristics, and in particular, an electrophotographic photoreceptor and an electrophotographic image forming having improved transfer characteristics at the time of transfer through a transfer sheet. To obtain a method and an electrophotographic apparatus.

[0009]

The electrophotographic photosensitive member of the present invention has a small diameter, and an electrophotographic image forming method and an electrophotographic method including a developing process using a toner having a small particle size and a transferring process through a sheet. This is a photoconductor used in an apparatus, and in the present invention, the above problem is solved by making surface energy lower than that of a conventional photoconductor.

That is, the present invention uses a photosensitive drum having an outer diameter of 65 mm or less and a toner having a weight average particle diameter of 8 μm or less to perform transfer through a sheet having a volume resistivity of 10 ¹⁰ to 10 ¹⁹ Ωcm. Used in image forming devices,
In an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support, the outermost layer of the photosensitive member has a contact angle of 1 with pure water.
It is an electrophotographic photosensitive member characterized by having an angle of 10 ° or more.

The present invention includes at least charging, exposure, development,
In an electrophotographic image forming method for forming an image on a transfer material through the transfer and cleaning steps, the developing step is carried out using the following toner weight average particle diameter of 8 [mu] m, the transfer step is 10 ¹⁰ to 10 ¹⁹ [Omega] cm of 2. An electrophotographic image forming method using the electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member is formed through a sheet having a volume resistivity and has an outer diameter of 65 mm or less.

The present invention also provides at least charging, exposure,
In an electrophotographic apparatus that forms an image on a transfer material through development, transfer and cleaning steps, the development step is performed using a toner having a weight average particle size of 8 μm or less, and the transfer step is performed at 10 ¹⁰ to 10 ¹⁹ Ωcm. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, which is formed through a sheet having a volume resistivity and has an outer diameter of 65 mm or less.

According to the present invention, the outer diameter of the photoconductor is φ65 m.
m or less, the weight average particle diameter of the toner used is 8 μm or less, and the releasability of the toner from the surface of the photoconductor is high even in an electrophotographic apparatus in which transfer is performed through a transfer sheet. It is possible to realize an electrophotographic photosensitive member having a high transfer efficiency and capable of obtaining a high-quality image.

The method for realizing the above electrophotographic photosensitive member can be achieved, for example, by including a fluorine-based resin powder in the outermost layer of the photosensitive member, but is not limited thereto.

Specific examples of the fluororesin powder include polymers such as tetrafluoroethylene, hexafluoropropylene, trifluoroethylene, chlorotrifluoroethylene, vinylidene fluoride, vinyl fluoride, perfluoroalkyl vinyl ether, and the like. Is used. The particle size of the fluororesin powder can be used in the range of 0.01 to 5 μm, and the molecular weight thereof is 3000 to 500.
A range of 0000 is preferred.

The fluororesin powder is dispersed as a photosensitive layer composition together with a binder resin. As a dispersing method, a sand mill, a ball mill, a roll mill, a homogenizer, a nanomizer, a paint shaker, an ultrasonic wave or the like is used. At the time of dispersion, a fluorinated surfactant, graft polymer, coupling agent, or the like may be used supplementarily.

The content of the fluororesin powder is preferably 4 to 70% by weight, more preferably 10 to 55% by weight in the outermost surface layer of the photoreceptor. If it is less than 4% by weight, the reduction of the surface energy is insufficient, and if it exceeds 70% by weight, the film strength of the surface layer is lowered.

As the binder resin for dispersing the fluororesin powder, polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene,
Examples thereof include polycarbonate, polyamide, polypropylene, polyimide, polyamideimide, polysulfone, polyallyl ether, polyacetal, nylon, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin and butyral resin. Furthermore, reactive epoxy, (meth)
Acrylic monomers and oligomers can also be mixed and used after curing.

The photosensitive layer of the present invention has a single layer or a laminated structure. In the case of a single layer structure, generation and movement of photocarriers are carried out in the same layer, and the fluororesin powder of the present invention is contained in this layer which is the outermost surface layer. In the case of a laminated structure, a charge generation layer that generates photocarriers and a charge transport layer that moves carriers are laminated. The surface layer may be formed by either the charge generation layer or the charge transport layer. In any case, the fluorine-based resin powder, which is an example of the present invention, is added to at least the layer forming the outermost surface layer (FIG. 6). The single-layer photosensitive layer preferably has a thickness of 5 to 100 μm, more preferably 10 to 60 μm. The charge generation material and the charge transport material are preferably contained in 20 to 80% by weight, more preferably 30 to 70% by weight. In the laminated photoreceptor, the thickness of the charge generation layer is preferably 0.001 to 6 μm.
m, more preferably 0.01 to 2 μm. The amount of charge generating material is preferably 10 to 100% by weight, more preferably 40 to 100% by weight. The thickness of the charge transport layer is preferably 5 to 100 μm, more preferably 10 to 60 μm.
m. The amount of charge transport material is preferably 20-80% by weight, more preferably 30-70% by weight.

The charge generating material used in the present invention includes phthalocyanine pigments, polycyclic quinone pigments, azo pigments,
Perylene pigment, indigo pigment, quinacridone pigment, azurenium salt dye, squarylium dye, cyanine dye,
Examples thereof include pyrylium dye, thiopyrylium dye, xanthene dye, quinoneimine dye, triphenylmethane dye, styryl dye, selenium, selenium-tellurium, amorphous silicon, and cadmium sulfide.

As the charge transport material used in the present invention, a pyrene compound, a carbazole compound, a hydrazone compound, an N, N-dialkylaniline compound, a diphenylamine compound, a triphenylamine compound, a triphenylmethane compound, a pyrazoline compound, a styryl compound,
Examples thereof include stilbene compounds.

In the electrophotographic photoreceptor of the present invention, a protective layer may be laminated on the photosensitive layer. The thickness of the protective layer is preferably 0.01 to 20 μm, more preferably 0.1 to 1
0 μm. The protective layer may contain the above-mentioned charge generating material or charge transporting material, metal and its oxides, nitrides, salts, alloys, and also conductive materials such as carbon and tin oxide. At this time, the fluororesin powder of the present invention is also included in the protective layer which is the outermost surface layer. As the binder resin used for the protective layer, polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, polyamideimide, polysulfone, polyallyl ether, polyacetal, nylon, phenol resin, acrylic resin, silicone Examples thereof include resins, epoxy resins, urea resins, allyl resins, alkyd resins, butyral resins and the like. In addition, reactive epoxy,
(Meth) acrylic monomers and oligomers can also be used after being mixed and cured.

The conductive support used in the electrophotographic photosensitive member of the present invention is a metal or alloy of iron, copper, nickel, aluminum, titanium, tin, antimony, indium, lead, zinc, gold, silver, or the like. Oxides and carbon,
A conductive resin or the like can be used. The shape may be cylindrical, belt-like or sheet-like. In addition, the conductive material,
Sometimes it is molded, but it can be applied as paint,
You may vapor-deposit.

An undercoat layer may be provided between the conductive support and the photosensitive layer. The undercoat layer is mainly composed of a binder resin, but may contain the above-mentioned conductive material or acceptor.
As the binder resin forming the undercoat layer, polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, polyamideimide, polysulfone, polyallyl ether, polyacetal, nylon, phenol resin, acrylic resin , Silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, butyral resin and the like.

As the method for producing the electrophotographic photosensitive member of the present invention, methods such as vapor deposition and coating are used. For coating, bar coater, knife coater, roll coater, attritor,
Spraying, dipping coating, electrostatic coating, powder coating and the like are used.

An electrophotographic apparatus according to the present invention is shown in FIG. Reference numeral 1 denotes a photoconductor drum, 2 denotes a transfer drum having a transfer sheet, and the photoconductor drum and the transfer drum may be driven in association with each other by a gear, a belt, or may have independent drive systems. . This electrophotographic device can be used as an output device for a copying machine, a printer, a facsimile, or the like.

The image forming process is basically carried out in the order of charging, exposure, development, transfer, cleaning, and static elimination, and by repeating these in sequence, color superposition is performed to reproduce a color image. First, after charging the surface of the photoconductor with a charging device 3 such as a corotron or a scorotron, information processing such as a reading device or a computer, a storage medium 4
A light source 5 such as a laser, an LED, or a liquid crystal shutter, which is controlled by a digital image signal sent from the device, irradiates a dot-shaped minute optical image on the photoconductor. The optical image generates charge carriers in the photoconductor and erases the surface charge of the photoconductor to form a dot-shaped minute electrostatic latent image. The image signal is color separated into three colors of cyan, magenta and yellow, or four colors obtained by adding black to them, and after electrostatic latent images corresponding to the respective colors are formed,
The developing device 6 corresponding to each color sequentially develops.
The three-color or four-color developing device is arranged in a fixed manner (FIG. 2) arranged side by side with respect to the photoconductor, laterally moved (FIG. 3), vertically moved (FIG. 4), or rotationally moved (FIG. 1) to sequentially expose the photosensitive material. There is a movement method that contacts the body. Separately from this, three or four photoconductors are arranged corresponding to each color, and an image of only one color of the color separated on each photoconductor is formed, and sequentially formed on the transfer material. There is also a method (FIG. 5) of reproducing a color image by transferring and superimposing colors.

In any case, the image developed with the toner is transferred to a transfer material such as transfer paper through the sheet in the transfer step. The transfer material is electrostatically or mechanically fixed to the surface of the transfer sheet in order to transfer the three-color or four-color images in multiple transfer onto one transfer material.

To transfer the toner from the photosensitive member onto the transfer material, a transfer charger 7 such as a corotron, a scorotron, a conductive brush, a conductive roller or the like is mainly used by an electrostatic force having a polarity opposite to that of the toner. At the same time, a pressure member may be used in combination to impart a transfer effect by pressure.
In order to support the transfer material, the transfer drum 2 is generally one in which a film, a mesh or the like is stretched in a cylindrical shape on a cylindrical frame, but the transfer drum 2 is not limited to this. The materials for the film and mesh include polyethylene terephthalate, polycarbonate, polyester, polysulfone, polyarylate, polyphenylene oxide, polyimide, polyamide, nylon, polyethylene oxide,
Various resins such as polystyrene and polyacetal, and polymer alloys containing them are used. In addition, the film and mesh may contain a conductive material such as metal, metal oxide, carbon, and conductive polymer.

The thickness of the transfer sheet is 25 to 500 μm.
The range of m is preferable, and the volume resistance is 10 ¹⁰ to 10 ¹⁹ Ω.
It can be used in the range of cm.

The residual toner after transfer is removed by cleaning 8. As a cleaning method, it is desirable to adopt blade cleaning in order to realize a simpler device configuration in association with space saving of the device.
The blade cleaning has a simple configuration in which an elastic member such as a plate-shaped polyurethane is merely abutted on the photoconductor in the generatrix direction. The abutting direction of the blade cleaning is a forward direction in which the blade tip is oriented in the rotation direction of the photoconductor, a counter direction in which the blade tip is oriented in the direction opposite to the rotation direction of the photoconductor, and a case where the photoconductor and the blade are vertical, etc. There is. Further, the blade is not limited to a single blade, but a plurality of blades can be used together. Further, a cleaning brush, a web, a magnetic brush or the like may be used in combination as an auxiliary.

[0032]

EXAMPLES Next, specific examples of the present invention will be shown below. [Example 1] 10 parts by weight of conductive titanium oxide (tin oxide coating, average primary particle size 0.4 μm), 10 parts by weight of phenol resin precursor (resole type), 10 parts by weight of methanol,
And 10 parts by weight of butanol were dispersed in a sand mill, and then dip-coated on an aluminum cylinder having an outer diameter of 60 mm and a length of 340 mm, and cured at 140 ° C. to obtain a volume resistance of 5 × 10.
A conductive layer having a thickness of ⁹ Ωcm and a thickness of 20 μm was provided.

Next, 10 parts by weight of the following methoxymethylated nylon (degree of methoxymethylation is about 30%):

[0034]

Embedded image And 150 parts by weight of isopropanol were mixed and dissolved, and then dip-coated on the conductive layer to form an undercoat layer of 1 μm.

Next, 10 parts by weight of the following azo pigment,

[0036]

Embedded image Polycarbonate resin (bisphenol A, molecular weight 30
000) 5 parts by weight and 700 parts by weight of cyclohexanone were dispersed by a sand mill and then dip-coated on the undercoat layer to obtain a charge generation layer having a thickness of 0.05 μm.

Next, 10 parts by weight of the following triphenylamine,

[0038]

Embedded image Polycarbonate resin (bisphenol Z, molecular weight 20
000) 10 parts by weight, 50 parts by weight of monochlorobenzene,
And 15 parts by weight of dichloromethane were mixed by stirring, and then dip-coated on the charge generation layer. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300000) 4 parts by weight, polycarbonate resin (bisphenol Z, molecular weight 80000) 6 parts by weight, monochlorobenzene 120 parts by weight, and dichloromethane 80 parts by weight were dispersed and mixed in a sand mill. To this, 3 parts by weight of the triphenylamine (1) was added, mixed and dissolved, and applied by spray coating on the charge transport layer to provide a protective layer of 6.5 μm to obtain a photosensitive drum.

[Comparative Example 1] In the photosensitive member of Example 1,
The photoconductor in which the charge transport layer was coated without providing the protective layer was used as the photoconductor drum of Comparative Example 1.

[Contact Angle] The contact angles of pure water on the surface of the photosensitive drums were compared with each other using a dropping type contact angle meter. As a result, the contact angle of the photoconductor of Example 1 was as large as 120 ° and a low energy surface was realized, whereas in Comparative Example 1, the contact angle was as small as 80 ° and a low energy surface was not obtained. It was

[Transfer Efficiency] Each photoconductor was set in the apparatus shown in FIG. 5 and the initial transfer efficiency was measured. A negative polarity scorotron was used for charging, and a laser having a wavelength of 670 nm was used for exposure. A two-component negative polarity toner having a weight average particle diameter of 8 μm was used as the toner, and transfer was performed with a positive polarity conductive rubber blade through a polycarbonate film having a thickness of 150 μm and a volume resistance of 2 × 10 ¹⁴ Ωcm. The transfer efficiency was calculated after measuring the toner density transferred to the transfer material and the toner density remaining on the photoconductor with a reflection type Macbeth densitometer when the halftone solid pattern was output in a single color. The image density of the halftone solid pattern was set to 0.80 by the reflection type Macbeth density measurement on the transfer material. In Example 1, the transfer efficiency was as high as 92%, whereas in Comparative Example 1, the transfer efficiency was as low as 78%. It was also found that the measured value of the contact angle had a correlation with the actual transfer efficiency, and the transfer efficiency was found to increase as the surface energy decreased.

[Example 2] The same materials as in Example 1 were prepared up to the aluminum cylinder, the conductive layer, the undercoat layer and the charge generation layer.

Next, the triphenylamine (1) 10
Parts by weight, polycarbonate resin (bisphenol Z, molecular weight 20000) 10 parts by weight, monochlorobenzene 50
After stirring and mixing 15 parts by weight of dichloromethane and 15 parts by weight of dichloromethane, the charge generation layer was dip-coated. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300,000) 3 parts by weight, polycarbonate resin (bisphenol Z, molecular weight 80,000) 5.5
By weight, 120 parts by weight of monochlorobenzene and 80 parts by weight of dichloromethane were dispersed and mixed in a sand mill. To this, 2.5 parts by weight of the triphenylamine (1) was added, mixed and dissolved, and applied by spray coating on the charge transport layer, and a protective layer of 6 μm was provided to obtain a photosensitive drum of Example 2.

The contact angle of this photoconductor with pure water is 11
It was 5 ° and the surface energy was sufficiently low. Further, when this photoconductor was put into the apparatus shown in FIG. 1 and the transfer efficiency was measured, it showed a good value of 90%.

[Example 3] The same materials as in Example 1 were prepared up to the aluminum cylinder, the conductive layer, the undercoat layer, and the charge generation layer.

Next, 3 parts by weight of the triphenylamine (1), 7 parts by weight of the following triphenylamine,

[0049]

Embedded image Polycarbonate resin (bisphenol Z, molecular weight 20
000) 10 parts by weight, 50 parts by weight of monochlorobenzene,
And 15 parts by weight of dichloromethane were mixed by stirring, and then dip-coated on the charge generation layer. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300,000) 3 parts by weight, polycarbonate resin (bisphenol Z, molecular weight 80,000) 5.5
By weight, 120 parts by weight of monochlorobenzene and 80 parts by weight of dichloromethane were dispersed and mixed in a sand mill. To this, 2.5 parts by weight of the triphenylamine (2) was added, mixed and dissolved, and applied onto the charge transport layer by spray coating, and a protective layer of 6 μm was provided to obtain a photosensitive drum of Example 3.

The contact angle of this photoconductor with pure water is 11
It was 6 ° and the surface energy was sufficiently low. Further, when this photoconductor was put into the apparatus shown in FIG. 5 and the transfer efficiency was measured, it showed a good value of 90%.

Example 4 The same as Example 1 was prepared up to the aluminum cylinder, the conductive layer, the undercoat layer and the charge generation layer.

Next, 3 parts by weight of the triphenylamine (1), 7 parts by weight of the triphenylamine (2), a polycarbonate resin (bisphenol Z, molecular weight 2000)
0) 10 parts by weight, 50 parts by weight of monochlorobenzene, and 15 parts by weight of dichloromethane were mixed by stirring, and then dip-coated on the charge generation layer. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300,000) 4 parts by weight, polycarbonate resin (bisphenol Z, molecular weight 80,000) 3.5
By weight, 120 parts by weight of monochlorobenzene and 80 parts by weight of dichloromethane were dispersed and mixed in a sand mill. To this, 2 parts by weight of the triphenylamine (2) was added, mixed and dissolved, and applied on the charge transport layer by spray coating, and a protective layer of 5 μm was provided to obtain a photosensitive drum of Example 4.

The contact angle of this photoreceptor with pure water is 12
It was 2 ° and the surface energy was sufficiently low. Further, when this photoreceptor was put into the apparatus shown in FIG. 5 and the transfer efficiency was measured, it was a good value of 93%.

[Embodiment 5] The same materials as in Embodiment 1 were prepared up to the aluminum cylinder, the conductive layer, the undercoat layer and the charge generation layer.

Next, 3 parts by weight of the triphenylamine (1), 7 parts by weight of the triphenylamine (2), a polycarbonate resin (bisphenol A, molecular weight 2500)
0) 10 parts by weight, 50 parts by weight of monochlorobenzene, and 15 parts by weight of dichloromethane were mixed by stirring, and then dip-coated on the charge generation layer. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300,000) 3 parts by weight, polycarbonate resin (bisphenol A, molecular weight 100,000) 5.
5 parts by weight, 120 parts by weight of monochlorobenzene, and 80 parts by weight of dichloromethane were dispersed and mixed in a sand mill.
To this, 2.5 parts by weight of the triphenylamine (2) was added, mixed and dissolved, and applied by spray coating on the charge transport layer, and a protective layer of 5 μm was provided to obtain a photosensitive drum of Example 5.

The contact angle of this photoconductor with pure water is 11
It was 3 ° and the surface energy was sufficiently low. Further, when this photoconductor was put into the apparatus shown in FIG. 5 and the transfer efficiency was measured, it was a good value of 89%.

Example 6 The same as Example 1 was prepared up to the aluminum cylinder, the conductive layer, the undercoat layer and the charge generation layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300000) 2 parts by weight, polycarbonate resin (bisphenol Z, molecular weight 25000) 4 parts by weight, monochlorobenzene 20 parts by weight, and dichloromethane 15 parts by weight were dispersed and mixed in a sand mill. to this,
Add 6 parts by weight of the triphenylamine (2), mix and dissolve, and apply by dip coating on the charge generation layer to give 25 μm.
A photoconductor drum of Example 6 was prepared by providing a charge transport layer of m.

The contact angle of this photoconductor with pure water is 11
It was 2 ° and the surface energy was sufficiently low. Further, when this photoconductor was put into the apparatus shown in FIG. 5 and the transfer efficiency was measured, it showed a good value of 88%.

Example 7 The same materials as in Example 1 were prepared up to the aluminum cylinder, the conductive layer, the undercoat layer and the charge generation layer.

Next, the triphenylamine (2) 10
Parts by weight, polycarbonate resin (bisphenol Z, molecular weight 25000) 10 parts by weight, monochlorobenzene 50
After stirring and mixing 15 parts by weight of dichloromethane and 15 parts by weight of dichloromethane, the charge generation layer was dip-coated. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, polyhexafluoropropylene resin fine powder (emulsion polymerization fine powder, average particle size 0.39)
μm, molecular weight about 500,000) 3 parts by weight, polycarbonate resin (bisphenol Z, molecular weight 100,000)
5.5 parts by weight, 120 parts by weight of monochlorobenzene, and 80 parts by weight of dichloromethane were dispersed and mixed in a sand mill. To this, 2.5 parts by weight of the triphenylamine (2) was added, mixed and dissolved, and applied by spray coating on the charge transport layer, and a protective layer of 5 μm was provided to obtain a photosensitive drum of Example 7.

The contact angle of this photoconductor with pure water is 11
It was 5 ° and the surface energy was sufficiently low. Further, when this photoconductor was put into the apparatus shown in FIG. 5 and the transfer efficiency was measured, it showed a good value of 90%.

[Comparative Example 2] The same materials as in Example 1 were prepared up to the aluminum cylinder, the conductive layer, the undercoat layer and the charge generation layer.

Next, polytetrafluoroethylene resin fine powder (emulsion polymerization fine powder, average particle size 0.27 μm)
m, molecular weight about 300,000) 1.0 part by weight, polycarbonate resin (bisphenol Z, molecular weight 25,000) 5
By weight, 20 parts by weight of monochlorobenzene and 15 parts by weight of dichloromethane were dispersed and mixed in a sand mill. To this, 4 parts by weight of the triphenylamine (2) was added, mixed and dissolved, and coated on the charge generation layer by dip coating,
A photoconductor drum of Comparative Example 2 was prepared by providing a 5 μm charge transport layer.

The contact angle of this photoreceptor with pure water is 10
It was 5 ° and the surface energy was high. Further, when this photoconductor was put into the apparatus shown in FIG. 1 and the transfer efficiency was measured, it was not good at 80%.

[Comparative Example 3] The same materials as in Example 1 were prepared up to the aluminum cylinder, the conductive layer, the undercoat layer and the charge generation layer.

Next, the triphenylamine (1) 10
Parts by weight, polycarbonate resin (bisphenol Z, molecular weight 25000) 10 parts by weight, monochlorobenzene 50
After stirring and mixing 15 parts by weight of dichloromethane and 15 parts by weight of dichloromethane, the charge generation layer was dip-coated. The coated cylinder was dried with hot air to form a 20 μm charge transport layer.

Next, 6 parts by weight of a polycarbonate resin (bisphenol Z, molecular weight 100,000), 3 parts by weight of the above triphenylamine (1), and monochlorobenzene 120.
1 part by weight and 80 parts by weight of dichloromethane are added, mixed and dissolved, and then applied on the charge transport layer by spray coating.
A photoconductor drum of Comparative Example 3 was prepared by providing a protective layer of μm.

The contact angle of this photoreceptor with pure water is 85.
The surface energy was high. Further, when this photoconductor was put into the apparatus shown in FIG. 5 and the transfer efficiency was measured, it was not good at 70%.

Comparative Example 4 The transfer efficiency was measured under the same photosensitive layer and process conditions as in Comparative Example 2 except that the outer diameter of the cylinder of the photosensitive member was 80 mm and the apparatus shown in FIG. 1 was used. It showed a good value of 88%.

[Comparative Example 5] The transfer efficiency was measured using the same photosensitive member and apparatus as in Comparative Example 2 except that the toner having the weight average particle diameter of 13 μm was used, and the result was 90%, which was a good value.

[Comparative Example 6] The transfer efficiency was measured using the same photoreceptor and apparatus as in Comparative Example 2 except that the toner having a weight average particle diameter of 10 μm was used, and it was 86%, which was a good value. .

[Comparative Example 7] In FIG. 5, the same photosensitive member and apparatus as in Comparative Example 2 were used except that the transfer sheet was removed and a means for gripping only the end portion of the transfer material to convey the transfer material was provided. When the transfer efficiency was measured by the method, a good value of 88% was shown.

[0078]

As described above, according to the present invention,
By making the surface energy much lower than before, we have realized an electrophotographic photoreceptor with high transfer efficiency. As a result, especially in an electrophotographic apparatus having a small diameter electrophotographic photosensitive member and having a developing step using a toner having a small particle diameter and a transfer step through a sheet, there is no image defect such as transfer unevenness or void in transfer. It is possible to provide high quality images.

[Brief description of drawings]

FIG. 1 is an example of a schematic configuration diagram of an electrophotographic apparatus having a transfer process via a sheet.

FIG. 2 is an example of a schematic configuration diagram of an electrophotographic apparatus having a transfer process via a sheet.

FIG. 3 is an example of a schematic configuration diagram of an electrophotographic apparatus having a transfer process via a sheet.

FIG. 4 is an example of a schematic configuration diagram of an electrophotographic apparatus having a transfer process via a sheet.

FIG. 5 is an example of a schematic configuration diagram of an electrophotographic apparatus having a transfer process via a sheet.

FIG. 6 is a schematic diagram showing a configuration of a photoconductor.

[Explanation of symbols]

1 photoconductor drum 2 transfer drum, transfer belt 3 charger 4 reading device, information processing device, storage device, communication device, etc. 5 light source 6 developing device 7 transfer charger 8 cleaning device 9 static eliminator 10 fixing device 11 paper feeding 21 conductive Support 22 conductive layer 23 undercoat layer 24 charge generation layer 25 charge transport layer 26 protective layer 27 single-layer photosensitive layer 28 fluorine-substituted resin powder

Claims (7)

[Claims] 1. A photosensitive drum having an outer diameter of 65 mm or less and a toner having a weight average particle diameter of 8 μm or less are used, and 10 ¹⁰ to 1 are used.
In an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support, which is used in an image forming apparatus for transferring through a sheet having a volume resistivity of 0 ¹⁹ Ωcm, pure water of the outermost layer of the photosensitive member is used. An electrophotographic photosensitive member having a contact angle with 110 ° or more. 2. The electrophotographic photosensitive member according to claim 1, wherein the outermost layer of the photosensitive member contains a fluororesin powder. 3. The electrophotographic photosensitive member according to claim 1, wherein the outermost layer of the photosensitive member contains a polycarbonate resin. 4. The electrophotographic photosensitive member according to claim 1, wherein the outermost layer of the photosensitive member contains a charge transport material. 5. The electrophotographic photosensitive member according to claim 1, wherein the outermost layer of the photosensitive member is a layer provided as a protective layer after a charge generation layer and a charge transport layer are sequentially laminated. 6. An electrophotographic image forming method of forming an image on a transfer material through at least charging, exposing, developing, transferring and cleaning steps, wherein the developing step is carried out using a toner having a weight average particle diameter of 8 μm or less. , The transfer process is 1
An electrophotographic image forming method using the electrophotographic photosensitive member according to claim 1, which is performed through a sheet having a volume resistivity of 0 ¹⁰ to 10 ¹⁹ Ωcm and has an outer diameter of φ65 mm or less. 7. An electrophotographic apparatus which forms an image on a transfer material through at least charging, exposing, developing, transferring and cleaning steps, wherein the developing step is carried out using a toner having a weight average particle diameter of 8 μm or less, Transfer process is 10 ¹⁰ -1
An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1, which is formed through a sheet having a volume resistivity of 0 ¹⁹ Ωcm and has an outer diameter of φ65 mm or less.