JP2913104B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic photosensitive member comprising a nickel seamless belt.

[Conventional technology]

The electrophotographic photoreceptor is basically constituted by providing a photosensitive layer on a conductive support, and its shape may be various such as a cylindrical shape and a belt shape. Among them, the belt-shaped photoreceptor has an advantage that the degree of freedom of arrangement of a charging system, an exposure system, a development system, a transfer system, a cleaning system, and the like can be increased. When an electrophotographic photosensitive member having an endless belt shape is used in an electrophotographic process, the photosensitive member is driven using two or more rollers. As one of such belt-shaped photoreceptors, a photoreceptor using a seamless (seamless) belt mainly composed of nickel as a support has been proposed, for example, Japanese Patent Publication No. 52-87.
No. 74 discloses this. The seamless belt described in the publication, after forming a nickel thin layer of a predetermined thickness on the outer surface of a cylindrical mandrel made of chrome or stainless steel,
It is obtained by peeling the thin nickel layer from the mandrel.

[Problems to be solved by the invention]

However, in an electrophotographic photoreceptor using such a seamless belt as a support, if the copying cycle is repeated many times, the belt end may be cracked or a wavy irregular pattern may be formed on the back surface of the belt. In some cases, there is a drawback that the device may fail and the image quality may deteriorate.

An object of the present invention is to provide a seamless belt-shaped electrophotographic photosensitive member in which the drawbacks of the prior art are eliminated, and the end of the belt is prevented from being broken at the time of conveyance, and the occurrence of a wavy uneven pattern on the back surface is prevented. .

[Means for solving the problem]

The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that the above-mentioned drawbacks can be solved by giving a nickel seamless belt a specific Vickers hardness. Reached.

That is, according to the study of the present inventors, in an electrophotographic photoreceptor using a nickel seamless belt as a support, the hardness of the nickel seamless belt is such that the end of the belt is cracked,
It is greatly involved in the generation of wavy irregularities on the back,
It has been found that when the Vickers hardness is set to 400 to 500, these disadvantageous phenomena hardly occur.
If the Vickers hardness exceeds 500, cracks are likely to occur at the end of the belt due to repeated transport of the electrophotographic photosensitive member,
On the other hand, if the Vickers hardness is less than 400, the belt is too soft, and a wavy uneven pattern is likely to be generated on the back surface.

The electrophotographic photoreceptor of the present invention is basically constituted by providing a photosensitive layer on a support made of a nickel seamless belt having a specific Vickers hardness as described above.

The nickel seamless belt of the present invention is formed using electroplating. In this case, the hardness of the belt is controlled by adjusting the temperature, current density, plating solution concentration, etc. of the plating solution. In the present invention, the temperature of the plating solution is set to 40 ° C. or higher. If the temperature of the plating solution is lower than 40 ° C., the end of the belt may crack, which is not preferable. Hereinafter, the method for producing the nickel seamless belt and the photosensitive layer of the electrophotographic photosensitive member of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 schematically shows an apparatus for forming a nickel seamless belt by electroplating. The cylindrical mandrel 1 is suspended vertically in an electroplating tank 2 via a shaft 6 by an insulating support 7. The outer surface of the cylindrical mandrel 1 is made of a metal such as chrome or stainless steel, and the inner surface is made of an insulating member such as Teflon. The electroplating tank 2 is filled with the plating solution 3 and the plating solution 3
Is preferably 30 to 70 ° C. The nickel pieces 4 are arranged in an anode basket 5 provided so as to surround the cylindrical mandrel 1. The cylindrical mandrel 1 is 3 to 60 rp by an insulating pulley 8, an endless belt 9 and a motor 10.
It can be rotated at m.

The electroplating current is supplied from the DC power supply 12 to the electroplating tank 2. For this purpose, the positive electrode of the DC power supply 12 is connected to the anode basket 5 and the negative electrode is connected to the outer surface of the cylindrical mandrel via the electrode 11 and the conductive shaft 6.

In the present invention, nickel sulfamate is used as a plating solution. The thickness of the nickel seamless belt is determined by the product of the current density during plating and the plating time, but is suitably about 20 to 60 μm.

Next, a method for manufacturing a photosensitive layer will be described. As the photosensitive layer, an organic photosensitive layer is preferably used, and as a production method thereof, a dip coating method, a spray coating method, a curtain coating method, a nozzle coating method, or the like is used. Here, a case where an organic photosensitive layer is formed by using a spray coating method will be described as an example.

In FIG. 2, a nickel seamless belt support 17 is attached to a support 16. The support 17 is horizontally mounted and is rotated at a constant speed in a certain direction by rotating a belt 20 wound around a pulley 19 of a center shaft 18. 21 are installed in close proximity. The spray gun 21 is mounted on a scanning device 23 such as a screw in which the base 22 is set in parallel with the longitudinal direction of the support 17, a pipe 25 for leading a carrier gas to a jet nozzle 24 at the tip is provided, and a coating liquid tank is provided. Coating liquid pipe from 26 27
Are connected to each other, so that the application liquid is sucked by the ejection of the carrier gas from the ejection nozzle 24 and ejected together. Further, a gas pressure adjusting valve 28 is attached to the pipe 25.

The coating of the photosensitive layer is performed while the support 17 is mounted, and the scanning device 23 scans the spray gun 21 and ejects the coating solution in the coating solution tank 26 together with the carrier gas adjusted by the gas pressure adjusting valve 28. This is performed by spraying the support 17.

 Next, the photosensitive layer will be described.

In a single-layer type electrophotographic photoreceptor, the photosensitive layer is CdS, CdS
e, Se, dye-sensitized inorganic photoconductive powders such as ZnO and the like, phthalocyanines, azo pigments, indigo pigments, organic pigments such as perylene pigments, polyvinyl carbazole, oxazole derivatives, triphenylamine derivatives, pyrazoline,
It is manufactured by applying a coating liquid in which a charge transporting substance such as phenylhydrazone or α-stilbene derivative and a binder resin are dispersed in an appropriate organic solvent.

In the case of a laminated electrophotographic photosensitive member comprising an undercoat layer, a charge generation layer, and a charge transport layer, the undercoat layer is made of polyamide, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, polyvinyl methyl ether, polyvinyl pyrrolidone, poly-N-vinyl. Thermosetting resins such as imidazole, ethylcellulose, nitrocellulose, ethylene-acrylic acid copolymer, casein, gelatin, phenol, urea resins, thermosetting resins such as melamine, aniline, alkyd, unsaturated polyester, epoxy, etc. and oxidation to these resins It is composed of a dispersion of inorganic pigments such as titanium, zinc oxide, indium oxide, antimony oxide and tin oxide.

The solvents used here are cyclohexane, benzene,
Toluene, xylene, dichloromethane, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, monochlorobenzene, methanol, ethanol, butanol, methyl ethyl ketone, methyl isobutyl Ketone, methyl-n-amyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-n-propyl ketone, cyclohexanone,
Preferred are methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethyl acetate, butyl acetate, dioxane, tetrahydrofuran and the like.

The thickness of the undercoat layer is 0.1 to 10 μm, preferably 0.3 to 5 μm
It is about.

The charge generation layer may be formed only of the charge generation substance, or may be formed by uniformly dispersing the charge generation substance in a binder. The charge generating material is thus formed by dispersing these components in a suitable solvent, coating this on an undercoat layer and drying.

Examples of the charge generating substance include C.I. Pigment Blue 25 (Color Index (CI) 21180), C.I. Pigment Red 41 (CI. 21200), C.I. Acid Red 52 (CI. 45100), and C.I.
5210), a phthalocyanine pigment having a porphyrin skeleton, an azo pigment having a carbazole skeleton (described in JP-A-53-95033), and an azo pigment having a stilbene skeleton (see JP-A-53-138229). Azo pigments having a distyrylbenzene skeleton (JP-A-53-133455).
Azo pigments having a triphenylamine skeleton (described in JP-A-53-132547), azo pigments having a dibenzothiophene skeleton (described in JP-A-54-21728), oxadiazole Azo pigments having a skeleton (described in JP-A-54-12742), azo pigments having a fluorenone skeleton (described in JP-A-54-22834), and azo pigments having a bisstilbene skeleton (described in JP-A-54-22742) Azo pigments having a distyryloxadiazole skeleton (described in JP-A-54-2129) and azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-1734)
And trisazo pigments having a carbazole skeleton (described in JP-A-57-195767 and JP-A-57-195758), and CI Pigment Blue 16 (CI 741).
Phthalocyanine-based pigments such as 00), indigo-based pigments such as C-Ivat Brown 5 (CI 73410), C-Iabut Die (CI 73030), Argo Scarlet B (manufactured by Violet), Indance Scarlet R (manufactured by Bayer), etc. Organic pigments such as perylene-based pigments and squaric pigments: Inorganic pigments such as Se, Se alloys, CdS and amorphous Si can be used.

As the binder resin, polyamide, polyurethane, polyester, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide and the like are used.

The amount of the binder resin is suitably 5 to 100 parts by weight, preferably 10 to 50 parts by weight, per 100 parts by weight of the charge generating substance.

The solvent used here is tetrahydrofuran,
Preferred are cyclohexanone, dioxane, dichloroethane, cyclohexane, methyl ethyl ketone, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, dichloroethane, ethyl cellosolve and the like, or a mixed solvent thereof.

The average thickness of the charge generation layer is 0.01 to 2 μm, preferably 0.1 to 2 μm.
It is about 1 to 1 μm.

The charge transport layer is formed by dissolving a charge transfer material, a binder resin, and, if necessary, a plasticizer and a leveling agent in a suitable solvent, applying the solution on the charge generation layer, and drying.

Examples of the charge transport material include poly-N-vinylcarbazole and its derivatives, poly-γ-carbazolylethylglutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, and oxadiazole derivatives , Imidazole derivative, triphenylamine derivative, 9- (p-diethylaminostyryl) anthracene, 1,1-bis (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, phenylpyrazolines, α-stilbene derivative And other electron donating substances.

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, polyvinyl acetate, and polyvinyl chloride. Vinyl, polyvinylidene chloride, polyacrylate resin, 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, Thermoplastic or thermosetting resins such as urethane resins, phenol resins, and alkyd resins are exemplified.

As a solvent for forming the charge transport layer, tetrahydrofuran, dioxane, toluene, monochlorobenzene, 1,2-dichloroethane, cyclohexanone, methylene chloride, 1,1,2,2-tetrachloroethane, and a mixed solvent thereof are preferable. The thickness of the charge transport layer is 10 to 100 μm,
Preferably it is 20 to 40 μm.

Further, a protective layer may be provided on the charge transport layer. This protective layer can be formed as a layer in which ultrafine powder of metal or metal oxide is dispersed in a binder resin. Desirably, the binder resin is substantially transparent to visible and infrared light and excellent in electrical insulation, mechanical strength, and adhesiveness. For example, polyester resin, polycarbonate resin, polyurethane resin, epoxy resin, acrylic resin, vinyl chloride-vinyl acetate copolymer, silicone resin, alkyd resin, melamine resin, phenol resin, polyvinyl chloride resin, cyclized butadiene rubber, fluorine resin, etc. Can be used. Metal powders include gold, silver, aluminum,
Examples of iron, copper, nickel, and metal oxides include zinc oxide, titanium oxide, tin oxide, bismuth oxide, antimony oxide, and indium oxide.

Although the composition ratio of the binder resin and the metal or metal oxide of the protective layer varies depending on the combination of materials, the metal or metal oxide is used in the range of 5 to 500 parts by weight with respect to 100 parts by weight of the binder resin.

The thickness of the protective layer can be set between 0.5 and 30 μm as needed.

〔Example〕

 Next, the present invention will be described in more detail with reference to examples.

In the electroplating apparatus shown in Fig. 1, the outer diameter is 127.4mm and the length is 4
Using a 00 mm stainless steel cylindrical mandrel, nickel seamless belts A, B, C, D and E having a thickness of 30 μm were prepared under the following plating solution composition and plating conditions.

(Plating solution composition) 60% nickel sulfamate solution (Nippon Kagaku Sangyo) 450g / l Nickel bromide (Nippon Kagaku Sangyo) 5g / l Boric acid (Kanto Kagaku) 30g / l Additive (NSF-E Nippon Kagaku Sangyo) 5cc / l The nickel seamless belt thus produced was removed from the cylindrical mandrel, cut into a length of 300 mm, and then placed in ion-exchanged water (conductivity of 1 × 10 ⁻⁶ mho / cm or less).
Ultrasonic cleaning was performed for minutes.

Next, an undercoat layer coating solution consisting of 10 g of copolymerized nylon (CM8000, manufactured by Toray), 168 g of methanol (manufactured by Kanto Chemical), and 72 g of 1-butanol (manufactured by Kanto Chemical) was prepared, and the spray coating apparatus shown in FIG. On the above five nickel seamless belts, a subbing layer having a thickness of 0.32 μm was formed by coating under the following spray coating conditions.

(Spray coating conditions for the undercoat layer) Spray pressure 1.5kg / cm ² Spray nozzle-support distance 130mm Support rotation speed 73rpm Spray nozzle scan speed 4mm / sec Coating liquid discharge rate 1.7cc / min Scan frequency 7 times One side Next, a mixture of 20 g of a bisazo pigment of the following formula (I) (manufactured by Ricoh) and 380 g of cyclohexanone was placed in a ball mill pot, 100 mm SUS balls were used as mill members, and after ball milling for 48 hours, 400 g of cyclohexanone was further added. And milled for one hour.

After milling, the mill base was taken out, diluted with cyclohexanone so that the solid content temperature was 0.8% by weight, and stirred to prepare a dispersion for forming a charge generation layer.

This coating solution was applied under the following spray conditions, and a film thickness of 0.1
A charge generation layer having a thickness of μm was formed, and dried by heating at 100 ° C. for 10 minutes.

(Charge generation layer spray coating conditions) Spray pressure 1.5kg / cm ² Spray nozzle-support distance 90mm Support rotation speed 73rpm Spray nozzle scan speed 4mm / sec Coating liquid discharge rate 2.5cc / min Scan frequency 9 times continuous Thus, a charge transport layer coating solution having the following composition was prepared.

Charge transport material (Formula (II) below) (Ricoh) 7 g Polycarbonate resin (C-1400, Teijin Chemicals) 10 g Silicone oil (KF-50, Shin-Etsu Chemical) 0.002 g Tetrahydrofuran (Kanto Chemical) 83 g Cyclohexanone (Kanto) 150g (Α-phenylstilbene compound) This coating liquid was applied on a charge transport layer having a thickness of 22 μm under the following spray conditions, and was heated and dried at 100 ° C. for 60 minutes.

(Charge transport layer spray coating conditions) Spray pressure 1.5kg / cm ² Spray nozzle-support distance 80mm Support rotation speed 60rpm Spray nozzle scan speed 5mm / sec Coating liquid discharge rate 12.3cc / min Scan frequency 8 times The photoreceptor thus prepared was attached to a modified electrostatic copying machine (Myricopy M-10; manufactured by Ricoh) to evaluate the image. The Vickers hardness of the nickel seamless belt of the support was measured using a Terasawa-type micro hardness meter SM-II (manufactured by Taiyo Tester). The results are shown in Table 1.

As is evident from Table 1, in the electrophotographic photosensitive member using the nickel seamless belts B, C, and D produced according to the present invention, the generation of a wavy irregular pattern and the crack of the belt end are effectively prevented, and The effect of the invention was confirmed.

〔The invention's effect〕

The electrophotographic photoreceptor of the present invention is formed from a nickel sulfamate liquid having a liquid temperature of 40 ° C. or higher as a support, and has a Vickers hardness of 400 to 500. Cracks and the occurrence of wavy irregularities on the back surface can be effectively prevented, and a high-quality image can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing an example of an apparatus for preparing a nickel seamless belt of the electrophotographic photosensitive member of the present invention by electroplating, and FIG. 2 is a view of the electrophotographic photosensitive member of the present invention. FIG. 2 is a schematic view showing an example of an apparatus for coating and forming a photosensitive layer on a nickel seamless belt. DESCRIPTION OF SYMBOLS 1 ... Cylindrical mandrel, 2 ... Electroplating tank 3 ... Plating solution, 4 ... Nickel piece 5 ... Anode basket, 7 ... Support part 11 ... Electrode, 12 ... DC power supply 13 ... Nickel belt, 17 ... Support body 21 ... Spray gun , 23… Scanning device 24… Squirting nozzle

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Izumi Aiso 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Satoshi Inari 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (56) References JP-A-63-127250 (JP, A) JP-A-63-127249 (JP, A) JP-B-52-3616 (JP, B2) JP-B-52-8784 ( JP, B1)

Claims (1)

(57) [Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer provided on a conductive support, wherein the conductive support is formed from a nickel sulfamate solution having a liquid temperature of 40 ° C. or higher, and has a Vickers hardness of 400 to 400. An electrophotographic photoreceptor comprising 500 nickel seamless belts.