JP2001330975A - Full-color electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost fast full-color electrophotographic device having high durability which can form stable images in repeated use. SOLUTION: The full-color electrophotographic device is equipped with an arrangement of a plurality of image forming elements each comprising at least an electrifying means, image exposing means, developing means, transferring means and electrophotographic photoreceptor. The photoreceptor mounted in the image forming element which forms a black toner image has a protective layer as the outermost layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tandem type electrophotographic image forming apparatus. More specifically, the present invention relates to a high-speed full-color image forming apparatus.

[0002]

2. Description of the Related Art As a full-color image forming apparatus using an electrophotographic system, two systems are generally known. One is called a single type or a single drum type, in which one electrophotographic photosensitive member is mounted in the apparatus and four color developing members are mounted. In this method, four colors (cyan, magenta, yellow, and black) are applied to a photosensitive member or a transferred member (directly transferred to output paper or temporarily transferred to an intermediate transfer member, and then transferred to paper). A toner image is formed. In this case, a charging member disposed around the photoconductor, an exposure member,
The transfer member, the cleaning member, and the fixing member can be shared, and can be designed to be smaller and lower in cost than a tandem system described later.

On the other hand, there is another system called a tandem system or a tandem drum system. In this case, at least a plurality of electrophotographic photosensitive members are mounted in the apparatus. Generally, for one drum,
Each member of charging, exposure, development, and cleaning is arranged one by one to form one electrophotographic element, and a plurality (generally four) of these are mounted. In this method, a single color toner image is formed by one electrophotographic element, and the toner image is sequentially transferred to a transfer target to form a full color image. The first advantage of this method is that high-speed image formation is possible. This is because, as described above, toner images of each color can be produced by parallel processing. For this reason, the image forming processing time is about one-fourth the time required in the single system, and it is possible to cope with four times the high-speed printing. A second advantage is that the durability of each member provided in the electrophotographic element including the photoreceptor can be substantially increased. This is because, in the single system, each charging, exposure, and development process is performed four times with one photoconductor to form one full-color image, whereas in the tandem system, the above operation is performed once with one photoconductor. Because they only do it.

[0004] However, there is also a disadvantage that the entire apparatus becomes large and the cost becomes high. Regarding the increase in the size of the entire apparatus, a measure has been taken by reducing the diameter of the photosensitive member, reducing the size of each member provided around the photosensitive member, and reducing the size of one electrophotographic element. As a result, not only the miniaturization of the apparatus but also the effect of reducing the material cost have been brought about, and the cost reduction of the entire apparatus has progressed somewhat. However, with the downsizing and miniaturization of the apparatus, a new problem has arisen that the durability of each member including the photoreceptor mounted on the electrophotographic element must be increased.

To cope with such a problem, an image forming apparatus using amorphous silicon, which is a typical example of an inorganic photoconductive material, has been proposed. However, a photoconductor using amorphous silicon for the photoconductive layer has a charging ability. There is a problem that contrast is not obtained in each of the colors cyan, magenta and yellow. To solve this problem, Japanese Patent Laid-Open No. 10-3
No. 33393 describes a technique in which an amorphous silicon photoconductor having a specific thickness or more is used for a photoconductor using a black toner image, and an OPC (organic photoconductor) is used for other three colors. In this case, in order to cover the low charging ability of the amorphous silicon photoconductor, OP
C and the charge difference between the amorphous silicon photoconductor
0 V). Japanese Patent Application Laid-Open No. 11-82599 discloses a technique in which a photoconductor using a black toner image is formed of an a-SiC photoconductive layer having a specific thickness or more. Also in this case, the potential of the photosensitive member using the black toner image is controlled.

[0006] Both of the originals output by a full-color printer or copier are monochrome (black).
The printing rate is high, and the durability of the photoreceptor that forms a black toner image is increased to substantially increase the durability of the entire system. This concept is extremely reasonable in terms of life design considering cost.
However, if a plurality of image forming elements are used in one image forming apparatus and photoconductors having different photoconductive layers are installed, a problem arises in that a desired coloring cannot be obtained due to a difference in characteristics between the photoconductors. This point is also described in the above publication. In this regard, the technique described in the above-mentioned publication covers this drawback by performing a specific potential control.

However, in the above technique, when the environment in which the image forming apparatus is used changes, the characteristics of the photoreceptor change, and the desired control may not always be obtained. In addition, a function for performing a specific potential control is required, which increases the cost. Furthermore,
By using two types of photoconductors, the manufacturing cost of the photoconductor increases. In particular, OPCs made of organic materials
The photoreceptor having an inorganic photoconductive layer typified by amorphous silicon is produced by a wet coating method suitable for mass production, and the production cost is relatively low.
Generally, since a film is formed by a vacuum thin film forming method, very expensive equipment is required, and a batch method is used, resulting in low productivity. In view of the above, there has been a demand for a low-cost, high-durability full-color tandem-type electrophotographic apparatus.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a low-cost, high-speed, full-color electrophotographic apparatus capable of forming an image which is highly durable, stable for repeated use, and low in cost.

[0009]

As a result of repeated examinations based on the above-mentioned results, in order to satisfy at least the three pillars of low cost, high speed full color and high durability, the following conditions are required. Turned out to be essential. That is, 1. In order to increase the durability of a tandem-type electrophotographic apparatus (image forming apparatus) at low cost, it is necessary to improve the durability of an image forming element that forms a black toner image, which is the rate-determining of the durability. Specifically, it is necessary to increase the life of the image forming element that forms the black toner image to about twice the life of the image forming element that forms the other three color toner images. 2. In order to cope with various changes in the environment in which the electrophotographic apparatus is used, it is necessary that a plurality of image forming elements have substantially the same change in characteristics with respect to the environment (particularly, chargeability and light attenuation characteristics are important). 3. In order to realize low cost, it is necessary to produce a photoreceptor by a wet coating method using an organic photoconductive material with low production cost and material, and also to exhibit high electrostatic durability of the photosensitive layer itself. . Based on the above design guidelines, we examined the configuration of the image forming elements used in the tandem type full-color electrophotographic apparatus, and found that the photosensitive layer of the photoconductor mounted on multiple image forming elements was composed of an organic photoconductive material. The book has the same configuration. In order to increase the durability of the photoconductor mounted on the black toner image forming element, a protective layer is laminated on the photosensitive layer of the photoconductor mounted on the black toner image forming element. At this time, it is important that the photoreceptor provided with the protective layer to be used is compatible with the photoreceptor without the protective layer in terms of light attenuation characteristics and chargeability at initial and repeated use. In addition, the fact that the charge generating material used for the black and non-black toner image photoconductors is common means that, in addition to cost reduction, light attenuation characteristics at initial and after repeated use, charging stability, environmental characteristics This is advantageous for the stability of, for example. In particular, the azo pigment represented by the general formula (XI) and titanyl phthalocyanine having a specific crystal form have high sensitivity and high durability, and thus can be effectively used in the present image forming apparatus. By satisfying the above configuration requirements,
It was found that a low cost, highly durable and highly stable tandem type electrophotographic apparatus could be designed, and the present invention was completed.

[0010] Accordingly, the above object is achieved by the present invention comprising (1)
"A full-color electrophotographic apparatus in which a plurality of image forming elements each including at least a charging unit, an image exposing unit, a developing unit, a transfer unit, and an electrophotographic photoreceptor are arranged, and the image forming element that forms a black toner image A full-color electrophotographic apparatus having a protective layer on the outermost layer of a mounted photoconductor, and (2) a photosensitive layer of a photoconductor mounted on all image forming elements of the full-color electrophotographic apparatus, The above (1), which is an organic photosensitive layer.
Item 3), wherein the photosensitive layers of the photosensitive members mounted on all image forming elements of the full-color electrophotographic apparatus have the same configuration. )) Or the full-color electrophotographic apparatus according to (2)), (4) wherein the organic charge generating substance is
(5) The azo pigment is an azo pigment represented by the following formula (XI), wherein the azo pigment is an azo pigment or a phthalocyanine pigment. Full-color electrophotographic apparatus according to the above (4)

[0011]

Embedded image (Wherein Cp ₁ and Cp ₂ represent a coupler residue. R
₂₀₁ and R ₂₀₂ each represent any of a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, and a cyano group;
They may be the same or different. Cp ₁ and Cp ₂ are represented by the following formula (XII),

[0012]

Embedded image (In the formula, R ₂₀₃ represents a hydrogen atom, an alkyl group such as a methyl group or an ethyl group, or an aryl group such as a phenyl group.
R ₂₀₄ , R ₂₀₅ , R ₂₀₆ , R ₂₀₇ , and R ₂₀₈ each represent a hydrogen atom, a nitro group, a cyano group, a halogen atom such as fluorine, chlorine, bromine, or iodine, a trifluoromethyl group, a methyl group, an ethyl group, or the like. Represents an alkoxy group such as an alkyl group, a methoxy group or an ethoxy group, a dialkylamino group, or a hydroxyl group, and Z is an atom necessary for forming a substituted or unsubstituted aromatic carbocyclic ring or a substituted or unsubstituted aromatic heterocyclic ring. Represents a group. ) ", (6)" Cp of the azo pigment
₁ and Cp ₂ are different from each other, wherein the full-color electrophotographic apparatus according to the above (5),
(7) “the full-color electrophotographic apparatus according to the above (4), wherein the phthalocyanine pigment is a titanyl phthalocyanine pigment”, and (8) “the titanyl phthalocyanine is a CuKα characteristic X-ray (wavelength 1 .514
Diffraction peak at Bragg angle 2θ with respect to Å) (± 0.2
°), which is a titanyl phthalocyanine having a maximum diffraction peak at least at 27.2 °.

[0013] The object of the present invention is to provide (9) a photosensitive member mounted on an image forming element for forming a black toner image of the full-color electrophotographic apparatus, wherein the photosensitive member has a protective layer; A full-color electrophotographic apparatus according to any one of the above items (1) to (8), characterized by containing a filler ", (10)" A black toner image of the full-color electrophotographic apparatus is formed. (10) The full-color electrophotographic apparatus according to the above (9), wherein the protective layer of the photoreceptor mounted on the image forming element contains a charge transport material. The full-color electron according to item (10), wherein the charge transport material contained in the protective layer of the photoreceptor mounted on the image forming element for forming a black toner image is a polymer charge transport material. Photography Equipment " (12) "the full-color electrophotographic apparatus polymeric charge transporting substance contained in the protective layer of the mounted photoreceptor imaging element that forms a black toner image is, at least triarylamine structure main chain and /
Or (13) the full-color electrophotographic apparatus according to the above (11), wherein the support used for the photoconductor is a cylindrical support; (1) to (12), wherein the outer diameter of the support is 40 mm or less.
Item 1), a full-color electrophotographic apparatus according to any one of
4) The above-mentioned (1), wherein the full-color electrophotographic apparatus is a so-called digital electrophotographic apparatus in which image exposure is performed by writing an electrostatic latent image on a photoconductor using an LD or LED. Items to (1)
3) The full-color electrophotographic apparatus according to any one of the above items),
(15) "The charging means mounted on all the image forming elements of the full-color electrophotographic apparatus is in contact with or close to the photoreceptor, wherein (14) The full-color electrophotographic apparatus according to any one of (1) and (16), wherein in the full-color electrophotographic apparatus, a voltage in which an AC component is superimposed on a DC component is applied to the charging member, so that the photosensitive member is applied to the photoreceptor. (1) to (1), wherein charging is performed.
5) A full-color electrophotographic apparatus according to any one of the above items. "
Is solved by

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an electrophotographic apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram for explaining the electrophotographic apparatus of the present invention, and the following modified examples also belong to the category of the present invention. In FIG.
Drum-shaped photoconductors (1C), (1M), (1Y), (1
K) rotates in the direction of the arrow in the drawing, and the charging members (2C), (2)
M), (2Y), (2K), developing members (4C), (4M), (4Y), (4K) as developing means, cleaning members (5C), (5M), as cleaning means.
(5Y) and (5K) are arranged. Charging member (2
C), (2M), (2Y), and (2K) are charging members constituting a charging device for uniformly charging the surface of the photoconductor. The charging members (2C), (2M), (2Y), (2
K) and developing members (4C), (4M), (4Y), (4
Laser light (3C), (3M), (3C) from an exposure member as an image exposure means (not shown)
Y) and (3K) are irradiated, and the photoconductors (1C) and (1C)
M), (1Y), and (1K), an electrostatic latent image is formed. And such a photoconductor (1C),
Four image forming elements (6C), (6M), (6Y), and (6K) centered on (1M), (1Y), and (1K) are:
They are juxtaposed along a transfer conveyance belt (10) as a transfer material conveyance means. The transfer conveying belt (10) includes the developing members (4C), (4M), (4Y), (4K) and the cleaning member (5C) of each image forming unit (6C), (6M), (6Y), (6K). , (5M), (5Y), (5K)
(1C), (1M), (1Y), (1K)
Transfer brushes (11C), (11M), (1) for applying a transfer bias (voltage) to a surface (rear surface) of the transfer conveyor belt (10) which is on the back side of the photoreceptor side.
1Y) and (11K). The image forming elements (6C), (6M), (6Y), and (6K) have different toner colors inside the developing device, and the black toner image forming photoconductor (1K) according to the present invention is different from the other photoconductors. Only the configuration is different from that of the photoreceptor (a protective layer is laminated on the photosensitive layer of the photoreceptor of (1C), (1M), and (1Y)), and all other configurations have the same configuration.

In the color electrophotographic apparatus having the structure shown in FIG. 1, an image forming operation is performed as follows. First, each of the image forming elements (6C), (6M), (6Y),
At (6K), the photoconductors (1C), (1M), (1
(2C), (2M), (2Y), (2)
K) and then a laser beam (3
C), (3M), (3Y), and (3K) form an electrostatic latent image corresponding to the image of each color to be created. Next, the latent images are developed by the developing members (4C), (4M), (4Y), and (4K) to form toner images. Developing member (4
C), (4M), (4Y), and (4K)
(Cyan), M (Magenta), Y (Yellow), and K (Black) developing members that are developed on four photoconductors (1C), (1M), (1Y), and (1K). The toner images of the respective colors are superimposed on the transfer paper. The transfer paper (7) is sent out of the tray by the paper feed roller (8),
The sheet is temporarily stopped by a pair of registration rollers (9), and is sent to a transfer conveyance belt (10) at the same time as the image formation on the photoconductor. The transfer paper (7) held on the transfer / conveyance belt (10) is conveyed, and each photoconductor (1C),
Contact position with (1M), (1Y), (1K) (transfer section)
The transfer of each color toner image is performed. The toner images on the photoconductor are transferred brushes (11C), (11M), (11M).
Y), (11K) and the transfer bias applied to the photoconductors (1C), (1M), (1Y), and (1K) are transferred onto the transfer paper (7) by an electric field formed by a potential difference between the transfer bias and the photoconductors. . Then, the recording paper (7) on which the four color toner images are superimposed through the four transfer units is conveyed to the fixing device (12),
The toner is fixed, and is discharged to a discharge unit (not shown).
In addition, each photoconductor (1C), (1
M), (1Y), and (1K) remaining toner on the cleaning devices (5C), (5M), (5Y), and (5K).
Collected in K). In the example of FIG. 1, the image forming elements are arranged in the order of C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the transfer paper transport direction. However, the order is not limited to this order, and the color order is arbitrarily set. When a black-only document is prepared, providing a mechanism for stopping the image forming elements ((6C), (6M), (6Y)) other than black is particularly effective for the present invention. it can. Further, in FIG. 1, the charging member is in contact with the photoconductor,
By providing an appropriate gap (about 10 to 200 μm) between the two, the amount of wear of both can be reduced, and toner filming on the charging member can be reduced.
Can be used well.

The image forming means as described above may be fixedly incorporated in a copying machine, a facsimile, or a printer, but each electrophotographic element is incorporated in those apparatuses in the form of a process cartridge. You may. The process cartridge is one device (part) that includes a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a charge removing unit, and the like.

Hereinafter, an electrophotographic photosensitive member used in the present invention will be described with reference to the drawings. 2 to 4 are cross-sectional views showing an electrophotographic photosensitive member mounted on the electrophotographic element for forming a non-black toner image of the present invention. FIG. 2 shows the conductive support (3
1) A single-layer photosensitive layer (33) mainly composed of a charge generating substance and a charge transporting substance is provided thereon. FIGS. 3 and 4 are cross-sectional views showing another configuration example of the electrophotographic photoreceptor of the present invention, and show a charge generation layer (35) containing a charge generation material as a main component.
And a charge transport layer (37) mainly composed of a charge transport material. 5 to 7 are sectional views showing an electrophotographic photosensitive member mounted on the electrophotographic element for forming a black toner image of the present invention. A protective layer (39) is provided on the surface of the photosensitive layer, corresponding to the photosensitive layers shown in FIGS.
Is provided.

First, a photosensitive member mounted on an image forming element for forming a toner image other than black will be described. As the conductive support (31), those exhibiting conductivity of not more than 10 ¹⁰ Ω · cm, for example, metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxide Film or cylindrical plastic or paper coated with metal oxides such as indium by vapor deposition or sputtering, or plates made of aluminum, aluminum alloy, nickel, stainless steel, etc., and methods such as extrusion and drawing After forming into a tube, a tube or the like that has been subjected to surface treatment such as cutting, superfinishing, and polishing can be used. Also, Japanese Patent Application Laid-Open No. 52-3601
The endless nickel belt and the endless stainless belt disclosed in Japanese Patent Publication No. 6 can be used as the conductive support (31).

In addition, a support obtained by dispersing a conductive powder in a suitable binder resin on the above support and applying the same can also be used as the conductive support (31) of the present invention. This conductive powder includes carbon black, acetylene black, aluminum, nickel, iron, nichrome, copper,
Metal powder such as zinc and silver, conductive tin oxide, IT
And metal oxide powders such as O. The binder resins used simultaneously include polystyrene and styrene-
Acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin , Polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene,
Thermoplasticity such as poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin,
A thermosetting resin or a photocurable resin can be used. Such a conductive layer can be provided by dispersing the conductive powder and the binder resin in an appropriate solvent, for example, tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene, or the like, and applying the dispersion.

Further, a heat-shrinkable material containing the above-mentioned conductive powder in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber and Teflon (registered trademark) on a suitable cylindrical substrate. Also those that have a conductive layer provided by a tube,
It can be favorably used as the conductive support (31) of the present invention. Further, the present invention is effective when the support of the photoreceptor is cylindrical with a small diameter. It is particularly useful when the outer diameter of the support is 40 mm or less.

Next, the photosensitive layer will be described. The photosensitive layer may be a single layer or a laminated layer. For convenience of explanation, the photosensitive layer will be described first in the case of being composed of the charge generation layer (35) and the charge transport layer (37).

The charge generation layer (35) is a layer containing a charge generation substance as a main component. For the charge generation layer (35), known charge generation substances can be used. Representative examples thereof include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments,
Examples thereof include quinone-based condensed polycyclic compounds, squaric acid-based dyes, other phthalocyanine-based pigments, naphthalocyanine-based pigments, and azurenium salt-based dyes. These charge generating substances may be used alone or in combination of two or more.
The charge generation layer (35) is dispersed in a suitable solvent together with a binder resin if necessary by using a ball mill, an attritor, a sand mill, ultrasonic waves, or the like, and the resultant is coated on a conductive support and dried. It is formed by doing. In particular, the azo pigment represented by the general formula (XI) and titanyl phthalocyanine having a specific crystal form can be effectively used in the present image forming apparatus because of high sensitivity and high durability.

If necessary, the binder resin used for the charge generation layer (35) includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicon resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, Polysulfone, poly-N-vinylcarbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol And polyvinylpyrrolidone. The amount of the binder resin is suitably from 0 to 500 parts by weight, preferably from 10 to 300 parts by weight, per 100 parts by weight of the charge generating substance.

The solvents used here include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane,
Toluene, xylene, ligroin and the like can be mentioned. Particularly, ketone solvents, ester solvents and ether solvents are preferably used. As a method of applying the coating liquid, a method such as a dip coating method, a spray coat, a beat coat, a nozzle coat, a spinner coat, and a ring coat can be used. The thickness of the charge generation layer (35) is 0.01 to 5 μm.
The degree is appropriate, preferably 0.1 to 2 μm.
The fact that the charge generation material used for the black and non-black toner image photoconductors is common, in addition to cost reduction,
It is advantageous for the stability of light attenuation characteristics and chargeability at the initial stage and after repeated use, and the stability of environmental characteristics.

The charge transporting layer (37) can be formed by dissolving or dispersing the charge transporting substance and the binder resin in a suitable solvent, applying the solution on the charge generating layer and drying. If necessary, a plasticizer, a leveling agent, an antioxidant and the like can be added.

The charge transport material includes a hole transport material and an electron transport material. Examples of the electron transporting substance include chloranil, bromanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone,
2,4,8-trinitrothioxanthone, 2,6,8-
Examples thereof include electron accepting substances such as trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, and benzoquinone derivatives.

Examples of the hole transport material include poly-N-vinylcarbazole and its derivatives, poly-γ-carbazolylethylglutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, polysilane, Oxazole derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives,
α-phenylstilbene derivative, benzidine derivative, diarylmethane derivative, triarylmethane derivative, 9
And other known materials such as styryl anthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives and the like. These charge transport materials are used alone or in combination of two or more.

Examples of the binder resin include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, and polystyrene. Vinyl acetate, polyvinylidene chloride, polyarylate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, Urethane resin,
Thermoplastic or thermosetting resins such as phenolic resins and alkyd resins are exemplified.

The amount of the charge transporting substance is 20 to 300 parts by weight, preferably 40 to 150 parts by weight, per 100 parts by weight of the binder resin.
Parts by weight are appropriate. The charge transport layer has a thickness of 5-1.
It is preferable that the thickness be about 00 μm. As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used.

In the photoreceptor of the present invention, the charge transport layer (3
In 7), a plasticizer or a leveling agent may be added. As the plasticizer, those used as general plasticizers for general resins, such as dibutyl phthalate and dioctyl phthalate, can be used as they are.
About 30% by weight is appropriate. Examples of the leveling agent include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in a side chain. 1
% By weight is appropriate.

Next, the case where the photosensitive layer is a single-layer photosensitive layer (33) will be described. A photoconductor in which the above-described charge generating substance is dispersed in a binder resin can be used. The single-layer photosensitive layer can be formed by dissolving or dispersing the charge generating substance, the charge transporting substance, and the binder resin in an appropriate solvent, and applying and drying the same. Further, the photosensitive layer may be of a function-separated type to which the above-described charge transport material is added, and can be used favorably. If necessary, a plasticizer, a leveling agent, an antioxidant and the like can be added.

As the binder resin, the charge transport layer (3
In addition to using the binder resin described in 7) as it is, the binder resin described in the charge generation layer (35) may be mixed and used. Of course, the above-mentioned polymer charge transport materials can also be used favorably. The amount of the charge generating substance is preferably from 5 to 40 parts by weight, and the amount of the charge transporting substance is preferably from 0 to 190 parts by weight, more preferably 50 parts by weight, based on 100 parts by weight of the binder resin.
１５０150 parts by weight. The single-layer photosensitive layer is composed of
If necessary, apply a coating liquid dispersed with a dispersing machine using a solvent such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexane with a charge transporting material together with a charge transporting material, by dip coating, spray coating, bead coating, or the like. Can be formed. The thickness of the single-layer photosensitive layer is suitably about 5 to 100 μm.

In the photosensitive member of the present invention, an undercoat layer can be provided between the conductive support (31) and the photosensitive layer. The undercoat layer generally contains a resin as a main component. However, considering that the photosensitive layer is coated thereon with a solvent, these resins are resins having high solvent resistance to general organic solvents. desirable. Examples of such a resin include water-soluble resins such as polyvinyl alcohol, casein and sodium polyacrylate, alcohol-soluble resins such as copolymerized nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy resin. Curable resins that form a three-dimensional network structure, such as resins, are exemplified. Further, a fine powder pigment of a metal oxide exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moiré and reduce residual potential.

These undercoat layers can be formed by using an appropriate solvent and a coating method as in the above-mentioned photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. In addition, the undercoat layer of the present invention includes Al ₂
O ₃ provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), SiO ₂ , SnO ₂ , Ti
Those provided with an inorganic substance such as O ₂ , ITO, CeO ₂ by a vacuum thin film forming method can also be used favorably. In addition, known materials can be used. The thickness of the undercoat layer is 0 to 5 μm
Is appropriate.

In the present invention, each layer is provided with an antioxidant, a plasticizer, a lubricant, an ultraviolet absorber, a low molecular weight compound, for the purpose of improving environmental resistance, in particular, for the purpose of preventing a decrease in sensitivity and a rise in residual potential. Charge transport materials and leveling agents can be added. Representative materials of these compounds are described below.

Examples of the antioxidant that can be added to each layer include, but are not limited to, the following. (A) Phenol compound 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, n-octadecyl-3- (4′- Hydroxy-3 ′, 5′-di-t-butylphenol),
2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- (4-
Ethyl-6-t-butylphenol), 4,4′-thiobis- (3-methyl-6-t-butylphenol),
4,4′-butylidenebis- (3-methyl-6-t-butylphenol), 1,1,3-tris- (2-methyl-4-hydroxy-5-t-butylphenyl) butane,
1,3,5-trimethyl-2,4,6-tris (3,5
-Di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ', 5'-di-
t-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis (4'-hydroxy-3'-t-butylphenyl) butyric acid] crylic ester, tocopherols, etc. .

(B) Paraphenylenediamines N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl- p-
Phenylenediamine, N, N'-di-isopropyl-p
-Phenylenediamine, N, N'-dimethyl-N, N '
-Di-t-butyl-p-phenylenediamine and the like.

(C) Hydroquinones 2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t
-Octyl-5-methylhydroquinone, 2- (2-octadecenyl) -5-methylhydroquinone and the like.

(D) Organic sulfur compounds Dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, ditetradecyl-3,3'-thiodipropionate and the like.

(E) Organic phosphorus compounds Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine and the like.

Examples of the plasticizer which can be added to each layer include the following, but are not limited thereto. (A) Phosphate ester plasticizers triphenyl phosphate, tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, trichloroethyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, Triphenyl phosphate and the like.

(B) Phthalate ester plasticizer Dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, di-n-phthalate Octyl, dinonyl phthalate, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, butyl benzyl butyl, butyl lauryl phthalate, methyl oleyl phthalate, octyl decyl phthalate, dibutyl fumarate, Dioctyl fumarate and the like.

(C) Aromatic carboxylic ester plasticizers Trioctyl trimellitate, Tri-n trimellitate
-Octyl, octyl oxybenzoate and the like.

(D) Aliphatic dibasic ester plasticizers Dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, di-n-adipate
Octyl, n-octyl-n-octyl-n-decyl adipate, diisodecyl adipate, dicapryl adipate, di-2-ethylhexyl azelate, dimethyl sebacate,
Diethyl sebacate, dibutyl sebacate, di-n-octyl sebacate, di-2-ethylhexyl sebacate, di-2-ethoxyethyl sebacate, dioctyl succinate, diisodecyl succinate, dioctyl tetrahydrophthalate, dihydrotetraphthalate -N-octyl and the like.

(E) Fatty acid ester derivatives butyl oleate, glycerin monooleate, methyl acetylricinoleate, pentaerythritol ester, dipentaerythritol hexaester,
Triacetin, tributyrin and the like.

(F) Oxyacid ester plasticizers Methyl acetyl ricinoleate, butyl acetyl ricinoleate, butyl phthalyl butyl glycolate, tributyl acetyl citrate and the like.

(G) Epoxy plasticizer Epoxidized soybean oil, epoxidized linseed oil, butyl epoxy stearate, decyl epoxy stearate, octyl epoxy stearate, benzyl epoxy stearate, dioctyl epoxy hexahydrophthalate, epoxy hexahydrophthalate Didecyl acid and the like.

(H) Dihydric alcohol ester plasticizers Diethylene glycol dibenzoate, triethylene glycol di-2-ethyl butyrate and the like.

(I) Chlorinated plasticizers Chlorinated paraffin, chlorinated diphenyl, chlorinated fatty acid methyl, methoxy chlorinated fatty acid methyl and the like.

(J) Polyester plasticizer Polypropylene adipate, polypropylene sebacate, polyester, acetylated polyester and the like.

(K) Sulfonic acid derivative p-toluenesulfonamide, o-toluenesulfonamide, p-toluenesulfonethylamide, o-toluenesulfonethylamide, toluenesulfone-N-ethylamide, p-toluenesulfon-N-cyclohexyl Amides and the like.

(L) Citric acid derivatives Triethyl citrate, acetyl triethyl citrate, tributyl citrate, tributyl acetyl citrate, tri-2-ethylhexyl acetyl citrate, n-octyldecyl acetyl citrate and the like.

(M) Others terphenyl, partially hydrogenated terphenyl, camphor, 2
-Nitrodiphenyl, dinonylnaphthalene, methyl abietic acid and the like.

Examples of the lubricant that can be added to each layer include the following, but are not limited thereto. (A) Hydrocarbon compounds Liquid paraffin, paraffin wax, microwax, low-polymerized polyethylene and the like.

(B) Fatty Acid Compounds Lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid and the like.

(C) Fatty acid amide compound Stearyl amide, palmityl amide, olein amide, methylene bis stearoamide, ethylene bis stearoamide and the like.

(D) Ester compounds Lower alcohol esters of fatty acids, polyhydric alcohol esters of fatty acids, polyglycol esters of fatty acids and the like.

(E) Alcohol compounds Cetyl alcohol, stearyl alcohol, ethylene glycol, polyethylene glycol, polyglycerol and the like.

(F) Metal soaps Lead stearate, cadmium stearate, barium stearate, calcium stearate, zinc stearate, magnesium stearate and the like.

(G) Natural waxes Carnauba wax, candelilla wax, beeswax, whale wax, botaro wax, montan wax and the like.

(H) Others Silicone compounds, fluorine compounds and the like.

Examples of the ultraviolet absorber that can be added to each layer include the following, but are not limited thereto. (A) Benzophenone 2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2 ′, 4-trihydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2,2′-dihydroxy-4- Methoxybenzophenone and the like.

(B) Salicylates Phenyl salicylate, 2,4-di-t-butylphenyl 3,5-di-t-butyl 4-hydroxybenzoate and the like.

(C) Benzotriazole type (2′-hydroxyphenyl) benzotriazole,
(2′-hydroxy 5′-methylphenyl) benzotriazole, (2′-hydroxy 5′-methylphenyl)
Benzotriazole, (2′-hydroxy 3′-tert-butyl 5′-methylphenyl) 5-chlorobenzotriazole.

(D) Cyanoacrylates Ethyl-2-cyano-3,3-diphenyl acrylate, methyl 2-carbomethoxy 3 (paramethoxy) acrylate and the like.

(E) Quencher (metal complex salt) Nickel (2,2'thiobis (4-t-octyl) phenolate) normal butylamine, nickel dibutyl dithiocarbamate, nickel dibutyl dithiocarbamate, cobalt dicyclohexyl dithiophosphate and the like.

(F) HALS (hindered amine) bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1 -[2- [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionyloxy] ethyl] -4- [3- (3,5-
Di-tert-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpyridine,
8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione, 4-benzoyloxy-2,
2,6,6-tetramethylpiperidine and the like.

Next, the photosensitive member mounted on the electrophotographic element for forming a black toner image will be described. In the photoreceptor for forming a black toner image, a protective layer (39) is provided on the photosensitive layer of the photoreceptor used for forming a non-black toner image for the purpose of protecting the photosensitive layer. In this case, the photosensitive layer may not be completely common, but by sharing the photosensitive layer, there is an advantage that the fatigue characteristics and environmental characteristics in repeated use are easy to be uniform, and an advantage that the cost can be suppressed. It is advantageous.

The function required for the protective layer of the present invention is at least high in mechanical durability (abrasion resistance). At this time, it is important that the photoconductor without the protective layer is compatible with the photoconductor characteristics or image characteristics at the initial stage and after repeated use.

In view of this point, the characteristics required for the protective layer include: i) good transmittance of image writing light ii) little charge trapping iii) no occurrence of an abnormal image such as image blur. Is mentioned.

Regarding the transmittance of the image writing light, when the light transmittance is reduced, the light amount to the photosensitive layer is reduced, and as a result, the light attenuation characteristic is changed. The transmittance is determined by the thickness of the protective layer, the filler content, the filler particle size, and the like.
It is desirable that the transmittance is close to 0%, but a transmittance of at least 80% or more is preferred. Regarding the thickness of the protective layer, 1 to 10 μm
m is appropriate, but it is desirable to set the optimum film thickness in accordance with the wear rate and the set life in the process using the photoconductor. Regarding the filler content, the higher the content, the better the wear resistance. However, if the content is too high, the electrostatic properties may be adversely affected, and conversely, the film formability may be reduced. Therefore, it is necessary to set an appropriate content, but about 5 to 40% by weight based on the total solid content of the protective layer is appropriate. As the filler particle size, the larger the one, the better the abrasion resistance.
For example, the transmittance of image light is reduced. As described below, the average particle size is preferably 1 μm or less, more preferably 0.1 μm or less.
5 μm or less.

Regarding the charge trap, when there are many traps, a residual potential is generated, which leads to an increase in the exposed portion potential. In order to avoid this, a material having an inadvertent polar group or the like may not be used, or an active site on the filler surface may be modified by surface treatment or the like. Also, the increase in the residual potential can be relatively prevented by a method of positively increasing the path of the electric charge. Specifically, this is the addition of a charge transporting substance to the protective layer, which will be described later in detail.

There are several types of abnormal images, but there are two main types. One is an image decrease in negative-positive development based on an increase in the residual potential, which can be prevented by the above-described method. The other is
Image blur (resolution reduction) can be mentioned. This is because the reactive gases (ozone, NOx
Etc.) due to the adhesion of the low-resistance substance to the surface of the photoreceptor, or due to the influence of a bulk low-resistance component on or near the surface of the photoreceptor. Regarding the former, it is possible to cope with the improvement by reducing the generation amount of the reactive gas and the like by improving the use process side (design of the air flow around the photoreceptor, adoption of the drum heater, use of the contact charging member, etc.). Regarding the latter, when the photosensitive layer is an organic photosensitive layer as in the present application, this effect is greater than in the case of a past process using an inorganic photosensitive layer. This is presumed as follows. One is the difference in charging polarity, and most inorganic photoconductors are used with positive charging. It has also been reported that the amount of reactive gas generated by positive charging is about one order of magnitude smaller than that of negative charging, and this effect is considered to be not negligible. Also, the dielectric constant and the resistance of the photosensitive layer are greatly different between the organic type and the inorganic type, and it is necessary to change the configuration of the protective layer accordingly. What needs to be greatly changed is the physical properties of the filler used.

In the case of the inorganic type, charging is performed not on the surface of the photoreceptor but on the surface of the photoreceptor inside or under the protective layer, using a filler having a relatively small resistance. When this configuration is applied to an organic photoreceptor, image blurring (resolution reduction) becomes remarkable. This is because the matching property between the protective layer of this configuration and the organic photoreceptor is poor.However, the inorganic photoreceptor was not used as a digital photoreceptor such as dot writing. This may be one of the reasons that did not make this problem manifest. To solve this problem, it is effective to use a filler having a large resistance.
It is effective to use one of ¹⁰ · Ωcm or more. More specifically, an inorganic pigment having a specific resistance of 10 ¹⁰ Ωcm or more,
Among them, specific resistance 10 ¹⁰ · [Omega] cm or more metal oxides, among others specific resistance 10 ¹⁰ · [Omega] cm or more silica, alumina, titanium oxide can be effectively used.

Materials used for the protective layer (39) include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, Polyallyl sulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyether sulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane And resins such as polyvinyl chloride, polyvinylidene chloride and epoxy resin. In addition, a filler material is added to the protective layer for the purpose of improving abrasion resistance. Examples of the organic filler material include fluororesin powder such as polytetrafluoroethylene, silicone resin powder, and a-carbon powder.Examples of the inorganic filler material include copper, tin, aluminum, and metal powder such as indium. Inorganic materials such as silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, antimony-doped tin oxide, tin-doped indium oxide and other metal oxides, and potassium titanate can be used. In particular, from the viewpoint of the degree of the filler, it is advantageous to use an inorganic material among them. In particular, silica, titanium oxide, and alumina can be used effectively.

Further, as a filler which is unlikely to cause image blur, a filler having a high electric insulation property (a specific resistance of 10 ¹⁰ Ω) is used.
Cm or more), and fillers having a pH of 5 or more and fillers having a dielectric constant of 5 or more can be particularly effectively used. In addition, a filler having a pH of 5 or more or a filler having a dielectric constant of 5 or more may be used alone, or a mixture of two or more fillers having a pH of 5 or less and a filler having a pH of 5 or more may be used. It is also possible to use a mixture of two or more fillers having a dielectric constant of 5 or less and a filler having a dielectric constant of 5 or more. In addition, among these fillers, α-alumina, which has high insulation properties, high thermal stability, and high abrasion resistance, has a hexagonal close-packed structure, is used to suppress image blur and improve abrasion resistance. Particularly useful.

Further, these fillers can be surface-treated with at least one kind of surface treatment agent, and it is preferable to do so from the viewpoint of dispersibility of the filler. The decrease in the dispersibility of the filler not only increases the residual potential, but also causes a decrease in the transparency of the coating film, the occurrence of coating film defects, and a decrease in abrasion resistance, which hinders high durability or high image quality. It can evolve into a big problem. As the surface treatment agent, all the surface treatment agents conventionally used can be used, but a surface treatment agent capable of maintaining the insulating property of the filler is preferable. For example, a titanate-based coupling agent, an aluminum-based coupling agent, a zircoaluminate-based coupling agent, a higher fatty acid, or the like, or a mixing treatment thereof with a silane coupling agent, Al ₂ O ₃ , Ti
O ₂ , ZrO ₂ , silicone, aluminum stearate, or the like, or a mixture thereof is more preferable from the viewpoints of filler dispersibility and image blur. Although the treatment with the silane coupling agent has a strong effect of image blur, the effect of mixing the surface treatment agent and the silane coupling agent may be suppressed in some cases. The amount of surface treatment varies depending on the average primary particle size of the filler used, but 3 to 30 wt% is suitable, and 5 to 20 wt%.
% Is more preferred. If the amount of the surface treatment is smaller than this, the effect of dispersing the filler cannot be obtained, and if the amount is too large, the residual potential is significantly increased. These filler materials are used alone or in combination of two or more.

The thickness of the surface layer is suitably about 0.1 to 10 μm. These filler materials can be dispersed by using an appropriate disperser. The average particle size of the filler is preferably 1 μm or less, more preferably 0.5 μm or less, from the viewpoint of the transmittance of the surface layer. When a protective layer is laminated, the importance of having the same characteristics as a photoreceptor having no other protective layer laminated thereon is as described above.

Further, a charge transporting substance can be used for the protective layer, which is an effective means in that an increase in residual potential due to lamination of the protective layer is suppressed. As the charge transporting material, the materials described in the description of the charge transporting layer can be used. Regarding the proper use of the hole transporting material and the electron transporting material, it is preferable to make an appropriate selection according to the polarity of the charging and the layer structure.

For the protective layer, a polymer charge transporting material having both a function as a charge transporting material and a function as a binder resin is preferably used. The protective layer composed of these polymer charge transport materials has excellent wear resistance and hole transport characteristics. As the polymer charge transport substance, known materials can be used. In particular, polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferably used. Among them, polymer charge transport materials represented by the general formulas (I) to (X) are preferably used, and these are exemplified below and specific examples are shown.

[0081]

Embedded imageWhere R₁, R_Two, R_ThreeAre each independently substituted or
Unsubstituted alkyl group or halogen atom, R_FourIs a hydrogen atom
Or a substituted or unsubstituted alkyl group, R_Five, R ₆Is replaced
Or an unsubstituted aryl group, o, p and q are each independently
An integer of 0 to 4; k and j represent compositions;
k ≦ 1, 0 ≦ j ≦ 0.9, n represents the number of repeating units
And an integer of 5 to 5000. X is an aliphatic divalent group,
A cycloaliphatic divalent group, or 2 represented by the following general formula:
Represents a valent group.

[0082]

Embedded image In the formula, R ₁₀₁ and R ₁₀₂ each independently represent a substituted or unsubstituted alkyl group, aryl group or halogen atom. l and m are integers of 0 to 4; Y is a single bond;
~ 12 linear, branched or cyclic alkylene groups,
-O -, - S -, - SO -, - SO 2 -, - CO -, -
CO—O—Z—O—CO— (wherein, Z represents an aliphatic divalent group) or

[0083]

Embedded image (In the formula, a represents an integer of 1 to 20, b represents an integer of 1 to 2000, and R ₁₀₃ and R ₁₀₄ represent a substituted or unsubstituted alkyl group or aryl group.) Where R ₁₀₁ and R
₁₀₂ , _R103 and _R104 may be the same or different.

[0084]

Embedded image In the formula, R ₇ and R ₈ represent a substituted or unsubstituted aryl group;
r ₁ , Ar ₂ and Ar ₃ represent the same or different arylene groups. X, k, j and n are the same as in the case of the general formula (I).

[0085]

Embedded image In the formula, R ₉ and R ₁₀ are a substituted or unsubstituted aryl group,
Ar ₄ , Ar ₅ and Ar ₆ represent the same or different arylene groups. X, k, j and n are the same as in the case of the general formula (I).

[0086]

Embedded image In the formula, R ₁₁ and R ₁₂ are a substituted or unsubstituted aryl group,
Ar ₇ , Ar ₈ and Ar ₉ are the same or different arylene groups, p
Represents an integer of 1 to 5. X, k, j and n are the same as in the case of the general formula (I).

[0087]

Embedded imageWhere R₁₃, R₁₄Is a substituted or unsubstituted aryl group,
Ar_Ten, Ar₁₁, Ar ₁₂Are the same or different arylene groups,
X₁, X_TwoIs a substituted or unsubstituted ethylene group, or
Alternatively, it represents an unsubstituted vinylene group. X, k, j and
And n are the same as in the case of the general formula (I).

[0088]

Embedded image In the formula, R ₁₅ , R ₁₆ , R ₁₇ and R ₁₈ are a substituted or unsubstituted aryl group, Ar ₁₃ , Ar ₁₄ , Ar ₁₅ and Ar ₁₆ are the same or different arylene groups, and Y ₁ , Y ₂ and Y ₃ are A single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, a vinylene group,
They may be the same or different. X, k, j and n
Is the same as in the case of the general formula (I).

[0089]

Embedded imageWhere R₁₉, R₂₀Is a hydrogen atom, a substituted or unsubstituted
Represents a reel group, R ₁₉And R₂₀May form a ring
No. Ar₁₇, Ar₁₈, Ar₁₉Are the same or different allylenes
Represents a group. X, k, j and n are the same as in the case of the formula (I).
Is the same.

[0090]

Embedded image In the formula, R ₂₁ is a substituted or unsubstituted aryl group, A
r ₂₀ , Ar ₂₁ , Ar ₂₂ and Ar ₂₃ represent the same or different arylene groups. X, k, j and n are the same as in the case of the general formula (I).

[0091]

Embedded image In the formula, R ₂₂ , R ₂₃ , R ₂₄ , and R ₂₅ are a substituted or unsubstituted aryl group, Ar ₂₄ , Ar ₂₅ , Ar ₂₆ , Ar ₂₇ , Ar ₂₈
Represents the same or different arylene groups. X, k, j and n are the same as in the case of the general formula (I).

[0092]

Embedded imageWhere R₂₆, R₂₇Is a substituted or unsubstituted aryl group,
Ar₂₉, Ar₃₀, Ar ₃₁Represents the same or different arylene groups
Express. X, k, j and n are the same as those in the general formula (I).
Is the same.

As a method for forming the protective layer, a usual coating method is employed. The thickness of the protective layer is suitably about 0.1 to 10 μm. In addition to the above, known materials such as aC and a-SiC formed by a vacuum thin film forming method can be used as the protective layer, but this is not very advantageous in terms of cost. Further, the above-mentioned various additives can also be used for the protective layer.

In the photosensitive member of the present invention, an intermediate layer can be provided between the photosensitive layer and the protective layer. The intermediate layer generally uses a binder resin as a main component. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the intermediate layer, a normal coating method is employed as described above. The thickness of the intermediate layer is suitably about 0.05 to 2 μm.

[0095]

The present invention will be described below with reference to examples.
The present invention is not limited by the embodiments. All parts are parts by weight. (Example 1) [Preparation of photoreceptor for toner image other than black] An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following compositions were sequentially coated on an aluminum cylinder. Dry,
3.5 μm intermediate layer, 0.2 μm charge generation layer, 25 μm
An electrophotographic photoreceptor comprising a m. m of the charge transport layer was formed.

Undercoat layer coating liquid Titanium dioxide powder 400 parts Melamine resin 65 parts Alkyd resin 120 parts 2-butanone 400 parts

Charge Generating Layer Coating Solution Titanyl phthalocyanine in the X-ray diffraction spectrum shown in FIG. 8 6 parts Polyvinyl butyral 4 parts 2-butanone 200 parts

Charge transport layer coating solution Polycarbonate 10 parts Charge transport material of the following structural formula 8 parts

[0099]

Embedded image 80 parts of methylene chloride

[Preparation of Photoreceptor for Black Toner Image] The charge transport layer of the photoreceptor for a toner image other than black was prepared using the same composition as
A photoreceptor was prepared in the same manner as above except that the protective layer coating solution having the following composition was laminated on the charge transport layer to 2 μm.

Coating solution for protective layer Polycarbonate 10 parts Methylene chloride 80 parts

(Example 2) An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating solution for the protective layer in Example 1 was changed to the following composition.

Coating solution for protective layer 10 parts of polycarbonate 3 parts of charge transporting material having the following structural formula

[0104]

Embedded image 80 parts of methylene chloride

Example 3 An electrophotographic photosensitive member was produced in the same manner as in Example 1, except that the coating solution for the protective layer in Example 1 was changed to the following composition.

Coating solution for protective layer Polycarbonate 10 parts Charge transporting material having the following structural formula 3 parts

[0107]

Embedded image Silica fine powder 1 part Methylene chloride 80 parts

Example 4 An electrophotographic photosensitive member was produced in the same manner as in Example 1, except that the coating composition for the protective layer in Example 1 was changed to the following composition.

Coating solution for protective layer Polymer charge transporting material having the following structure: 10 parts

[0110]

Embedded image Additive of the following structure 1 part

[0111]

Embedded image 100 parts of methylene chloride

Example 5 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the coating composition for the protective layer in Example 1 was changed to the following composition.

Coating solution for protective layer Polymer charge transporting material having the following structure: 10 parts

[0114]

Embedded image Additive of the following structure 1 part

[0115]

Embedded image Silica fine powder 3 parts Methylene chloride 80 parts

Example 6 A photoconductor was prepared by the same way as that of Example 3 except that titanium oxide was used instead of silica in the coating liquid for the protective layer in Example 3.

Example 7 A photoconductor was prepared by the same way as that of Example 3 except that alumina was used instead of silica in the coating liquid for the protective layer in Example 3.

Example 8 An electrophotographic photoreceptor was prepared in the same manner as in Example 3, except that the charge generation layer in Example 3 was changed to the one having the following composition, and was evaluated in the same manner.

[0119]

Embedded image 6 parts of trisazo pigment having the following structure

[0120]

Embedded image Polyvinyl butyral 5 parts 2-butanone 200 parts Cyclohexanone 400 parts

Comparative Example 1 The procedure was the same as in Example 1 except that the photoconductor for black toner images in Example 1 was shared with the photoconductor for toner images other than black.

The electrophotographic photosensitive member manufactured as described above was mounted on the electrophotographic apparatus shown in FIG. 1, and four image forming elements were monochrome (only black) under the following process conditions.
10,000 sheets, 10,000 full-color images, total 20
000 images were evaluated. Table 1 shows the results.

Charging condition: DC bias: -800 V AC bias: 2.0 kV (peak to peak) Frequency 2 kHz Exposure condition: 780 nm semiconductor laser (image writing by polygon mirror) Also, abrasion loss of charge transport layer after 15,000 sheets Was also measured.

[0124]

[Table 1]

Example 9 Using the photoreceptor prepared in Example 3, the charging condition of all the image forming elements of the apparatus shown in FIG. 1 was changed to a condition in which no AC bias was applied. Continuous printing of 20,000 sheets was performed. As a result, the images were good at the initial stage and after 20,000 sheets. However, in the image after 20,000 sheets, although at a level that does not cause any problem, slight image density unevenness (color unevenness) caused by charging unevenness occurred.

Example 10 Using the photoreceptor of Example 3,
The charging member of the electrophotographic apparatus as shown in FIG. 1 was changed from a charging roller to a scorotron charger. Charging was performed so that the same surface potential as in Example 3 was obtained.
000 images were output. As a result, 20,000
No special abnormal image was found up to the number of sheets, but Example 3
The smell of ozone was worse than that of.

Example 11 Using the photoreceptor of Example 3,
Example 3 The setting method of the charging member (contact with the photoconductor) of the electrophotographic apparatus as shown in FIG. 1 was changed to provide a gap of about 50 μm between the surface of the photoconductor and the surface of the charging member.
A running test of 15,000 sheets was performed in the same manner as described above.
As a result, the toner filming on the charging member was less than that of Example 3 and was good.

[0128]

As is apparent from the detailed and concrete description, according to the present invention, an electrophotographic apparatus for high-speed full-color electrophotography which is durable and capable of forming an image stable for repeated use and which is inexpensive. Has an extremely excellent effect of providing.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining an electrophotographic apparatus of the present invention.

FIG. 2 is a cross-sectional view illustrating an electrophotographic photosensitive member mounted on an electrophotographic element for forming a toner image other than black in the present invention.

FIG. 3 is a cross-sectional view illustrating an electrophotographic photosensitive member mounted on an electrophotographic element for forming a toner image other than black in the present invention.

FIG. 4 is a cross-sectional view illustrating an electrophotographic photosensitive member mounted on an electrophotographic element for forming a toner image other than black in the present invention.

FIG. 5 is a cross-sectional view illustrating an electrophotographic photosensitive member mounted on the electrophotographic element for forming a black toner image of the present invention.

FIG. 6 is a cross-sectional view showing an electrophotographic photosensitive member mounted on the electrophotographic element for forming a black toner image of the present invention.

FIG. 7 is a cross-sectional view illustrating an electrophotographic photosensitive member mounted on the electrophotographic element for forming a black toner image of the present invention.

FIG. 8 is a diagram showing titanyl phthalocyanine in the X-ray diffraction spectrum used in Example 1 of the present invention.

[Explanation of symbols]

 1C Photoconductor 1M Photoconductor 1Y Photoconductor 1K Photoconductor 2C Charging member 2M Charging member 2Y Charging member 2K Charging member 3C Laser light 3M Laser light 3Y Laser light 3K Laser light 4C Developing member 4M Developing member 4Y Developing member 4K Developing member 5C Cleaning Member 5M Cleaning Member 5Y Cleaning Member 5K Cleaning Member 6C Image Forming Element 6M Image Forming Element 6Y Image Forming Element 6K Image Forming Element 7 Transfer (Recording) Paper 8 Feed Roller 9 Registration Roller 10 Transfer Conveying Belt 11C Transfer Brush 11M Transfer Brush 11Y Transfer brush 11K transfer brush 12 fixing device 31 conductive support 33 photosensitive layer 35 charge generation layer 37 charge transport layer 39 protective layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) G03G 5/147 503 G03G 5/147 503 504 504 15/01 111 15/01 111A

Claims (16)

[Claims] 1. A full-color electrophotographic apparatus in which a plurality of image forming elements each including at least a charging unit, an image exposing unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member are arranged, and forms a black toner image. A full-color electrophotographic apparatus comprising a protective layer on the outermost layer of a photoreceptor mounted on an image forming element. 2. The full-color electrophotographic apparatus according to claim 1, wherein a photosensitive layer of a photoconductor mounted on all image forming elements of said full-color electrophotographic apparatus is an organic photosensitive layer. 3. The full-color electrophotographic apparatus according to claim 1, wherein the photosensitive layers of the photoconductors mounted on all the image forming elements of the full-color electrophotographic apparatus have the same configuration. 4. The full-color electrophotographic apparatus according to claim 3, wherein the organic charge generating substance is an azo pigment or a phthalocyanine pigment. 5. The full-color electrophotographic apparatus according to claim 4, wherein the azo pigment is an azo pigment represented by the following formula (XI). Embedded image (Wherein Cp ₁ and Cp ₂ represent a coupler residue. R
₂₀₁ and R ₂₀₂ each represent any of a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, and a cyano group;
They may be the same or different. Further, Cp ₁ and Cp ₂ are represented by the following formula (XII): (In the formula, R ₂₀₃ represents a hydrogen atom, an alkyl group such as a methyl group or an ethyl group, or an aryl group such as a phenyl group.
R ₂₀₄ , R ₂₀₅ , R ₂₀₆ , R ₂₀₇ , and R ₂₀₈ each represent a hydrogen atom, a nitro group, a cyano group, a halogen atom such as fluorine, chlorine, bromine, or iodine, a trifluoromethyl group, a methyl group, an ethyl group, or the like. Represents an alkoxy group such as an alkyl group, a methoxy group or an ethoxy group, a dialkylamino group, or a hydroxyl group, and Z is an atom necessary for forming a substituted or unsubstituted aromatic carbocyclic ring or a substituted or unsubstituted aromatic heterocyclic ring. Represents a group. ) 6. The full-color electrophotographic apparatus according to claim 5, wherein Cp ₁ and Cp ₂ of the azo pigment are different from each other. 7. The full-color electrophotographic apparatus according to claim 4, wherein the phthalocyanine pigment is a titanyl phthalocyanine pigment. 8. The method according to claim 1, wherein the titanyl phthalocyanine is CuK.
As a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to characteristic X-rays of α (wavelength 1.514 °), at least 2
The full-color electrophotographic apparatus according to claim 7, which is titanyl phthalocyanine having a maximum diffraction peak at 7.2 °. 9. The photoconductor mounted on an image forming element for forming a black toner image of the full-color electrophotographic apparatus has a protective layer, and the protective layer contains a filler. 9. The full-color electrophotographic apparatus according to any one of 1 to 8. 10. The full-color electronic device according to claim 9, wherein a protective layer of a photoconductor mounted on an image forming element for forming a black toner image of the full-color electrophotographic apparatus contains a charge transport material. Photo equipment. 11. A charge transport material contained in a protective layer of a photoreceptor mounted on an image forming element for forming a black toner image of the full-color electrophotographic apparatus is a polymer charge transport material. The full-color electrophotographic apparatus according to claim 10. 12. The polymer charge transporting substance contained in a protective layer of a photoreceptor mounted on an image forming element for forming a black toner image of the full-color electrophotographic apparatus has at least a triarylamine structure in a main chain and / or 12. The full-color electrophotographic apparatus according to claim 11, wherein the apparatus is a polycarbonate contained in a side chain. 13. The support according to claim 1, wherein the support used for the photoconductor is a cylindrical support, and the outer diameter of the cylindrical support is 40 mm or less. Full color electrophotographic equipment. 14. The so-called digital type electrophotographic apparatus in which the image exposure is performed by writing an electrostatic latent image on a photoreceptor by using an LD or an LED. 14. The full-color electrophotographic apparatus according to any one of items 13 to 13. 15. A charging unit mounted on all image forming elements of the full-color electrophotographic apparatus,
15. The full-color electrophotographic apparatus according to claim 1, wherein the apparatus is arranged in contact or close proximity. 16. The full-color electrophotographic apparatus according to claim 1, wherein the photosensitive member is charged by applying a voltage in which an AC component is superimposed on a DC component to the charging member. 2. The full-color electrophotographic apparatus according to item 1.