JPH0713379A - Electrophotographic photoreceptor and electrophotographic device with it - Google Patents

Abstract

PURPOSE:To provide an electrophotographic photoreceptor, which provides a high quality image and is excellent in durability, and an electrophotographic device provided with this photoreceptor. CONSTITUTION:In an electrophotographic photoreceptor, in which an intermediate layer, a photosensitive layer, and a surface protecting layer are provided in this order on a conductive supporting body, surface roughness Rz of the intermediate layer is 1.0mum or less while surface roughness Rz of the surface protecting layer is 1.0mum or less, and an electrophotographic device is provided with this photoreceptor. In this way, a high quality image can be obtained, and an electrophotographic photoreceptor, which is excellent in durability, and the electrophotographic device provided with this photoreceptor can be obtained.

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 and an electrophotographic apparatus, and more particularly to an electrophotographic photosensitive member and an electrophotographic apparatus having high image uniformity, reproducibility and durability.

[0002]

2. Description of the Related Art In recent years, an organic photoconductor (OPC) having a photosensitive layer made of an organic photoconductor has been widely used as an electrophotographic photoconductor. Conventionally, there were problems in sensitivity, durability, O ₃ resistance, NO _x resistance, etc., but these drawbacks have been overcome by improving and optimizing charge generating materials, charge transporting materials and binder resins. . It has been attempted to provide a surface protective layer on the photosensitive layer in order to further improve durability.

Further, a laser has recently been used as a light source of a copying machine equipped with an OPC photosensitive member. Since the laser is a coherent light, unless the light is completely absorbed between the photosensitive layers, the light reflected from the surface of the photosensitive layer and the surface of the support interfere with each other, and it is said that there is a problem called moire or interference fringes on an image which is said to be halftone. Cause Therefore, it is possible to suppress the interference with the surface of the photoconductor by absorbing or scattering the reflected light of the support to prevent moire.

[0004]

As a method of absorbing the reflected light of the above-mentioned support, a blackening method can be considered, but it is a substance having conductivity and excellent in environment resistance, withstand voltage and the like. Is not found. Also, as a method of scattering the reflected light, the surface is randomly roughened by buffing or the like, or grooves are regularly formed by cutting with a bite, etc., and the reflection direction of the light reaching the support is changed to cause interference. It is possible to prevent

In this case, in the former case, the shavings adhere to the surface of the support and do not fall off even after washing, and they appear as fog on the image, or the residue of the material to be cut that comes into contact with the support causes The adhesion of the photosensitive layer is impaired. In the latter case, it is difficult to obtain the effect unless the groove is deep. Therefore, there are drawbacks such as poor adhesion to the photosensitive layer and reflection of grooves on the image.

Therefore, an object of the present invention is to provide an electrophotographic photosensitive member and an electrophotographic apparatus which can obtain high image quality by suppressing moire and interference fringes on an image and have excellent durability.

[0007]

That is, the present invention provides an electrophotographic photoreceptor having an intermediate layer, a photosensitive layer and a surface protective layer in this order on a conductive support, and the surface roughness R _Z of the intermediate layer is 1.0 μm or less and surface roughness R of the surface protective layer
_The electrophotographic photoreceptor is characterized in that _Z is 1.0 μm or less.

In the present invention, when the laser light as the light source is incident on the surface protective layer, it is reflected by the intermediate layer and is emitted from the surface protective layer to the free surface, and the optical path is changed three times in total. Therefore, the reflected light on the surface protective layer and the reflected light on the intermediate layer do not interfere with each other. Further, since the surface of the intermediate layer is roughened, there are no problems such as when roughening the surface of the support.

Further, since the surface of the photosensitive member is roughened, the frictional resistance with the cleaning means such as the cleaning blade is reduced and the blade curl is eliminated.

When the surface roughness of the intermediate layer exceeds R _Z 1.0 μm, the photosensitive layer or the undercoat layer coated thereon is not sufficiently covered, resulting in image defects of white spots in the case of reversal development. Appears. Further, the surface roughness of the surface protective layer is R _Z 1.0
However, because of the synergistic effect, the laser spot shape becomes large and a high-definition image cannot be obtained. Also, when the surface protective layer exceeds R _Z 1.0 μm, similar results are obtained due to the synergistic effect with the surface roughness of the intermediate layer.

The photosensitive layer of the electrophotographic photoreceptor of the present invention contains at least a charge generating material and a charge transporting material. Examples of the charge generating material include phthalocyanine pigment, polycyclic quinone pigment, trisazo pigment, disazo pigment, azo pigment, perylene pigment, indigo pigment, quinacridone pigment, azurenium salt dye, squalium dye, cyanine dye, pyrylium dye, thiopyrylium dye, Examples include xanthene dyes, quinoneimine dyes, triphenylmethane dyes and styryl dyes.

Examples of charge transport materials include pyrene compounds, N-alkylcarbazole compounds, hydrazone compounds, N, N-dialkylaniline compounds, diphenylamine compounds, triphenylamine compounds, triphenylmethane compounds, pyrazoline compounds, styryl compounds, Examples thereof include stilbene compounds, polynitro compounds, polycyano compounds, and pendant polymers obtained by immobilizing these compounds on a polymer.

In many cases, the above-mentioned charge generating material, charge transporting material and the like are dispersed and contained in a binder resin binder having film forming properties to form a photosensitive layer and the like. As such a binder resin binder, polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide,
Polypropylene, polyimide, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin,
Examples thereof include allyl resin, alkyd resin, polyamide-imide, nylon, polysulfone, polyallyl ether, polyacetal, butyral resin and the like.

Next, the layer structure of the electrophotographic photosensitive member of the present invention will be described. Conductive supports include iron, copper, gold, silver, aluminum, zinc, titanium, lead, nickel, tin, antimony,
A metal or alloy such as indium, an oxide of the metal, carbon, a conductive polymer, or the like can be used.
There are a drum shape such as a cylindrical shape and a cylindrical shape, and a belt shape and a sheet shape. The conductive material may be molded as it is, used as a coating material, deposited, or processed by etching or plasma treatment. In the case of paint, not only the above-mentioned metals and alloys but also paper and plastic are used as the support.

The photosensitive layer in the photoreceptor of the present invention may have a single layer structure or a laminated structure. The thickness is 10
35 μm, preferably 15 to 30 μm.

In the case of the laminated structure, it is composed of at least a charge generation layer and a charge transport layer. The charge polarity is different depending on whether the charge generation layer is provided on the conductive support side or the charge transport layer. The polarity of toner used is different. The film thickness of the charge generation layer can be 0.001 to 6 μm, and more preferably 0.01 to 2 μm. The content ratio of the charge generating material contained in the charge generating layer is
It can be 10 to 100% by weight, more preferably 50 to 100% by weight. The thickness of the charge transport layer is the thickness of the photosensitive layer minus the thickness of the charge generation layer. The content of the charge transport material contained in the charge transport layer is 20 to 80% by weight, and more preferably 30 to 70% by weight.

An undercoat layer may be provided between the conductive support and the photosensitive layer. The undercoat layer functions as a charge injection control at the interface and as an adhesive layer. The undercoat layer is mainly composed of a binder resin, but may contain the above-mentioned metal or alloy, or their oxides, salts and surfactants. Specific examples of the binder resin forming the undercoat layer are polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, Examples thereof include allyl resin, alkyd resin, polyamide-imide, nylon, polysulfone, polyallyl ether, polyacetal, butyral resin and the like. The thickness of the undercoat layer is 0.05 to 7 μm, more preferably 0.1.
~ 2 μm. The intermediate layer is mainly composed of a binder resin, but also contains conductive particles. Specific examples of the binder resin include polyester, polyurethane, polyarylate, polyethylene,
Polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, polyamide-
Examples thereof include imide, nylon, polysulfone, polyallyl ether, polyacetal and butyral resin.

Further, as conductive particles, SnO ₂ , ITO
Etc. Further, organic or inorganic fine particles may be contained in order to increase the surface roughness of the intermediate layer.

The protective layer is always provided on the photosensitive layer. The protective layer is mainly made of resin, examples of which are polyester,
Polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenol resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, polyamide-imide, nylon, polysulfone, polyallyl ether,
Examples thereof include polyacetal and butyral resin. The thickness of the protective layer is in the range of 0.05 to 15 μm, preferably 1 to 10 μm.

Further, the protective layer has a charge transporting material for maintaining the charge transporting property, inorganic conductive particles for controlling the electric resistance of the layer, and fluorine atom-containing resin fine particles for reducing the frictional resistance of the surface. May be added. As specific examples, the charge transport materials are pyrene compounds, N-alkylcarbazole compounds, hydrazone compounds, N, N, respectively.
-Dialkylaniline compounds, diphenylamine compounds, triphenylamine compounds, triphenylmethane compounds, pyrazoline compounds, styryl compounds, stilbene compounds, polynitro compounds, polycyano compounds, and further
Examples include pendant polymers in which these compounds are fixed on a polymer.

Further, as the conductive particles, SnO ₂ , IT
O etc. are mentioned.

As the fluorine atom-containing resin fine particles, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polydichlorodifluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-
Hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer and the like can be mentioned.

As the method for producing the electrophotographic photosensitive member of the present invention, methods such as vapor deposition and coating are used. The coating method can form a wide range of films from thin films to thick films, and can form films of various compositions. Specifically, a bar coater,
It is applied by a knife coater, dip coating, spray coating, beam coating, electrostatic coating, roll coater, attritor, powder coating or the like.

The coating used when applying the protective layer is
It is obtained by dispersing the fluorine atom-containing resin fine particles in a binder resin and a solvent. As the dispersion method, a ball mill, ultrasonic wave, paint shaker, red devil, sand mill, or the like is used. The same dispersion method can be used when the conductive fine powder, the pigment, and the charge generation material are pigments.

[0025]

EXAMPLES The present invention will be described below with reference to examples. Example 1 First, a coating method will be briefly described.

50 parts by weight of conductive titanium oxide powder coated with tin oxide containing 10% antimony oxide, 25 parts by weight of phenol resin, 20 parts by weight of methyl cellosolve, 5 parts by weight of methanol and silicone oil (polydimethylsiloxane poly). 0.002 parts by weight of the oxyalkylene copolymer, number average molecular weight of 30,000) was dispersed for 2 hours in a sand mill using φ1 mm glass beads to prepare a conductive layer coating material. Aluminum cylinder (φ80 × 360mm)
The above coating composition was applied by dipping and dried at 140 ° C. for 30 minutes to form a conductive layer having a film thickness of 20 μm.

Next, 30 parts by weight of methoxymethylated nylon resin (number average molecular weight 32,000) and 10 parts by weight of alcohol-soluble copolymerized nylon resin (number average molecular weight 29000) are mixed solvent of 260 parts by weight of methanol and 40 parts by weight of butanol. The liquid dissolved therein was applied on the conductive layer by a dipping coating machine to form an undercoat layer having a film thickness after drying of 1 μm.

Next, a disazo pigment represented by the following structural formula [1]

[0029]

[Chemical 1]

4 parts by weight, 2 parts by weight of benzal resin, and 40 parts by weight of tetrahydrofuran were dispersed for 60 hours in a sand mill using φ1 mm glass beads and then diluted with a cyclohexanone / tetrahydrofuran mixed solvent to obtain a charge generation layer coating material. . This coating solution was applied onto the above-mentioned undercoat layer by a dipping coating machine to form a charge generation layer having a film thickness after drying of 0.1 μm.

Next, the following structural formula [2]

[0032]

[Chemical 2]

10 parts by weight of the charge transport material and 10 parts by weight of a polycarbonate resin (number average molecular weight 25,000)
20 parts by weight of dichloromethane and 40 of monochlorobenzene
The solution was dissolved in a part by weight of a mixed solvent, the solution was applied onto the charge generation layer by dipping, and dried at 120 ° C. for 60 minutes to form a charge transport layer having a thickness of 20 μm.

Next, 2 parts by weight of polytetrafluoroethylene fine particles (Lubron L-5: manufactured by Daikin Industries, Ltd.),
Disperse 4 parts by weight of a polycarbonate resin (bisphenol Z type, number average molecular weight 40,000) and 4 parts by weight of the charge transport material of the structural formula [2], 250 parts by weight of monochlorobenzene and 250 parts by weight of dichloromethane with a sand mill,
A protective layer paint was obtained. This coating material was applied by spray coating and dried at 120 ° C. for 60 minutes to form a 3.0 μm protective layer.

The above photoconductor was mounted on the electrophotographic apparatus shown in FIG.

The electrophotographic process of the electrophotographic apparatus shown in FIG. 1 will be described. The surface of the photosensitive drum 7, which rotates in the arrow direction by a drive system (not shown), is negatively charged by the primary charger 6. Next, the light of the semiconductor laser forms an electrostatic latent image on the drum surface through the polygon mirror 9, the optical system and the mirror 4. Then, the latent image is visualized by the negatively charged powder called the toner of the developer in the developing device 3 which is rotated by the developing device rotating body 1 and faces the drum.

On the transfer drum 23, which rotates in synchronization with the photosensitive drum 7, the toner image visualized by electrostatically adsorbing the transfer paper which has passed through the paper transport section from the cassette 17 is positively transferred to the transfer charger 25. Is output to the transfer paper. The toner remaining on the drum is scraped off the surface by the cleaning blade of the drum cleaner section 8. Then, the charge remaining on the surface of the drum is removed by the removing light.

The above is the process for the first color, but after the above process has been performed four times, the transfer charge is removed by the paper static eliminator 22, the transfer paper is separated from the transfer drum 23 by the separation charging device 21, and the transfer section 10 is moved. After passing, the fixing device 14 fixes the toner on the transfer paper. Table 1 shows the results of image formation by the above-mentioned electrophotographic apparatus using the electrophotographic photosensitive member obtained by the above coating method.

[0039] * Surface roughness is changed by adding silicone resin particles (trade name Tospearl) to the surface layer or intermediate layer. The addition amount is 0.5% by weight for 0.35 μm, 3% by weight for 0.61 μm, and 5% by weight for 0.83 μm.

As described above, an image was produced by changing the surface roughness of the intermediate layer and the surface roughness of the protective layer, but a high-definition image was obtained without causing defects such as interference fringes and moire.

Comparative Example 1 In Example 1, the surface roughness of the intermediate layer was set to R _Z 1.33 μm and a protective layer was not formed.

Comparative Example 2 The surface of a cylinder was spirally ground, and an undercoat layer, a charge generation layer and a charge transport layer were applied in this order on the surface of the cylinder in the same manner as in Example 1 to prepare a photoreceptor. Cylinder surface roughness is R
_{Z was} 1.2 μm.

Comparative Example 3 In Example 1, a photoreceptor having a protective layer and a surface roughness of the intermediate layer of R _{Z of} 0.61 μm was prepared.

In Comparative Examples 1 and 3, interference fringes and moire were generated on the image. Also, in the case of Comparative Example 2, interference fringes did not appear, but spiral grooves appeared in the image.

[0045]

As described above, according to the present invention,
It is possible to provide an electrophotographic photosensitive member and an electrophotographic apparatus which have high image quality and excellent durability.

[Brief description of drawings]

FIG. 1 is a schematic side view of an electrophotographic apparatus using an electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

 1 Developing Device Rotating Body 2 Hopper Part 3 Developing Device 4 Mirror 5 Dustproof Glass 6 Primary Charger 7 Photosensitive Drum 8 Part of Drum Cleaner 9 Polygon Mirror 10 Conveying Part 11 Pre-Fixing Charger 12 Oil Application Roller 13 Cleaning Web (Upper) 14 Fixing Device 15 Paper Ejection Roller 16 Cleaning Web (Bottom) 17 Cassette 18 Paper Feeding Roller 19 Conveying Roller 20 Registration Roller 21 Separation Charger 22 Paper Electrifier 23 Transfer Drum 24 Cleaning Brush 25 Transfer Charger

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoji Amemiya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masaaki Yamagami 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor ▲ Yoshi ▼ Kimihiro Mura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (4)

[Claims] 1. An electrophotographic photoreceptor having an intermediate layer, a photosensitive layer and a surface protective layer in this order on a conductive support, wherein the intermediate layer has a surface roughness R _Z of 1.0 μm or less and the surface protective layer. Has a surface roughness R _z of 1.0 μm or less. 2. The electrophotographic photoreceptor according to claim 1, wherein the surface protective layer contains 5 to 70% by weight of fluorine atom-containing resin fine particles. 3. The electrophotographic photosensitive member according to claim 1, wherein the surface protective layer contains a charge transport material. 4. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1.