JPH04122945A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To prevent the generation of abnormal images, such as moires, and toner filming, and to reduce the cost of production by applying photosensitive layers spirally at the specific max. surface roughness and specific pitch. CONSTITUTION:Coating is executed by discharging a coating liquid 10 from a nozzle 14 while rotating a base 11 and moving the nozzle 14. The base 11 is coated with the liquid 10 spirally at 0.2 to 0.2mm pitch so as to have 0.3 to 1.5mum max. surface roughness. The high sensitivity is obtd. in this way and the generation of the abnormal images, such as moires, is obviated. In addition, the toner filming is prevented. The moires are generated if the max. surface roughness is below 0.3mum. The toner filming arises if the max. surface roughness exceeds 1.5mum. Both cases are, therefore, undesirable. A cleaning defect is liable to arise unless the photosensitive layers are formed spirally at 0.2 to 2mm intervals.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor that does not produce abnormal images such as moiré.

[Conventional technology]

Generally, this type of electrophotographic photoreceptor is constructed by providing a photosensitive layer on a support made of aluminum, aluminum alloy, etc., either directly or via an intermediate layer, by vapor deposition, coating, or the like. Regarding the surface shape of the support, several regulations have been proposed so far. For example, JP-A-60-
No. 112049 discloses that the surface of the support is roughened, the roughened surface has flat groove-like unevenness, and the distance between the ridges is 20/2.
A technique is disclosed for improving the adhesion between the support and the photosensitive layer or intermediate layer by specifying that the peak height is 0.31a to 2. Also, JP-A-61-46
No. 966 describes the surface roughness of the support surface as O, OS,
~0.3 houses, the distance between the peaks of the uneven surface is 0.2-~1
0. A technique has been disclosed for preventing the occurrence of interference fringes such as moiré by defining n. In addition, special public service 1986-
42498, the maximum surface roughness of the support is 0.7.
A technique has been disclosed in which deterioration of sensitivity is prevented by setting the average surface roughness to 1 s or more and the average surface roughness to 0.5 or more.

However, with conventional electrophotographic photoreceptors constructed using supports based on the above-mentioned regulations, when images such as halftone images are produced, uneven shading occurs in the same pattern as the surface shape of the support. There is a disadvantage that it occurs.

For example, when copying a color document such as a catalog using a copier equipped with an electrophotographic photoreceptor that uses a support with a cut finish, white streaks in the same pattern as the cut surface may randomly appear on the image. occurs.

In order to solve these problems, we developed a process speed of 80 mm /
In an electrophotographic photoreceptor used in an electrophotographic process lasting more than a second, the average surface roughness of the photoreceptor is 0.3-5.0-
(Japanese Unexamined Patent Publication No. 1-99060) and an electrophotographic photoreceptor in which the surface roughness of the r photosensitive layer is 172 or more of the light wavelength of the light source used for image formation at a ten-point average roughness Rz. ” (Japanese Unexamined Patent Publication No. 163058/1983) has been proposed. Although these electrophotographic photoreceptors have relatively eliminated the above-mentioned drawbacks, the former photoreceptor has the disadvantage of high cost because it is necessary to polish the surface of the photoreceptor in the running direction with a wrapping tape. Moreover, since the coating film of the latter photoreceptor is sandy and rough, toner powder tends to stick to the surface, resulting in so-called toner filming.

[Problem to be solved by the invention]

The present invention has been made in view of the above-mentioned state of the prior art, and an object of the present invention is to provide an electrophotographic photoreceptor that can prevent the occurrence of abnormal images such as moiré and toner filming, and can be produced at low cost. With the goal.

[Means to solve the problem]

As a result of intensive studies to solve the above problems, the present inventors discovered that a photosensitive layer having a photosensitive layer coated in a spiral shape with a maximum surface roughness (Rffiax) of 0.3 to 1.5 μs and a pitch of 0.2 to 2 a+m The body was found to be suitable for the above purpose.

That is, according to the present invention, in an electrophotographic photoreceptor comprising a photosensitive layer provided on a support, the photosensitive layer has a maximum surface roughness (Rmax) of 0.3 to 1.54 and a pitch of 0.2 to 2 m.
Provided is an electrophotographic photoreceptor characterized in that the composition is coated in a spiral manner.

Since the electrophotographic photoreceptor of the present invention has the above-described structure, it has high sensitivity, does not generate abnormal images such as moiré, and can prevent toner filming.

If the maximum surface roughness (Rmax) of the photosensitive layer is less than 1.3, moire will occur, and if it exceeds 1.5, toner filming will occur, which is not preferable.

Furthermore, unless the photosensitive layers are coated in a spiral manner with an interval of 0.2 to 2 mm, cleaning failures tend to occur, making it impossible to achieve the intended purpose of the present invention.

Note that the term "spiral shape" as used in the present invention means that a spiral shape is formed in the local direction of the photoreceptor.

The present invention will be explained in more detail below.

As a support, aluminum, nickel, chromium, steel, tin oxide, indium oxide, etc. are deposited on the surface of a plastic circular tube or a plastic seamless belt, an endless nickel belt disclosed in JP-A No. 52-36016, an endless belt, etc. Stainless steel belt, aluminum, nickel, stainless steel, etc. 1. ．． 1. I...
Pipes are used that have been made into raw pipes by methods such as expanding and drawing, and then surface-treated by cutting, superfinishing, polishing, etc.

Next, the photosensitive layer will be described. The photosensitive layer may be of a single layer type or a laminated type.

In a single-layer electrophotographic photoreceptor, the photosensitive layer is CdS, C
Inorganic light guiding powders such as clSe, Se, dye-sensitized ZnO, phthalocyanine, organic pigments such as azo pigments, indigo pigments, perylene pigments, polyvinyl carbazole, oxazole derivatives, triphenylamine derivatives, pyrazoline, phenyl It is manufactured by applying a coating liquid in which a charge transporting substance such as hydrazones and α-stilbene derivatives and a binder resin are dispersed in a suitable organic solvent.

A laminated electrophotographic photoreceptor basically has a photosensitive layer consisting of a charge generation layer and a charge transport layer.

Even if the charge generation layer is formed only from a charge generation substance,
Alternatively, the charge generating material may be uniformly dispersed in the binder. The charge-generating material is therefore formed by dispersing these components in a suitable solvent, coating this directly on the support or on the undercoat layer, and drying.

Examples of the charge generating substance include CI Pigment Blue 25 [Color Index (CI) 2mm 180],
CI Pigment Red 41 (CI 2mm200)
, Sea Eye Acid Red 52 (CI 45100),
In addition to C.I. Basic Red 3 (CI 452mm0), phthalocyanine pigments with a porphyrin skeleton, azo pigments with a carbazole skeleton (Japanese Patent Application Laid-Open No. 1983-1997-
95033), azo pigments having a stilbene skeleton (described in JP-A-53-138229), azo pigments having a distyrylbenzene skeleton (described in JP-A-53-138229),
133455), azo pigments having a triphenylamine skeleton (described in JP-A-53-132547), azo pigments having a dibenzothiophene skeleton (described in JP-A-54-2mm728), oxadiazole Azo pigments having a skeleton (described in JP-A-54-12742), azo pigments having a fluorenone skeleton (described in JP-A-54-22834), azo pigments having a bisstilbene skeleton (described in JP-A-54-22834), 17733), azo pigments having a distyryloxadiazole skeleton (described in JP-A-54-2mm29), azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-2mm29),
17734), trisazo pigments having a carbazole skeleton (described in JP-A-57-195767 and JP-A-57-195758), indigo pigments such as CI Pigment Blue 16 (CI73030), and Argos. Car Red B (manufactured by Violet),
Perylene pigments such as Indane Scarlet R (manufactured by Bayer), organic pigments such as square link pigments: Se
, Se alloy, CdS, amorphous Si, and other inorganic pigments can be used.

Binder resins include polyamide, polyurethane,
Polyester, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone,
Polystyrene, poly-N-vinylcarbazole, polyacrylamide, etc. are used.

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

The solvent used here is preferably tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, cyclohexane, methyl ethyl ketone, 1.1.2-trichloroethane, 1,1,2.2-tetrachloroethane, dichloromethane, ethyl cellosolve, etc., or a mixed solvent thereof. .

The average thickness of the charge generation layer is 0. O1 to 2 tones, preferably about 0°1 to 1 tones.

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

As the charge transport substance, poly-N-vinylcarbazole and its derivatives, poly-γ-carbazolylethyl glutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, oxadiazole derivatives , imidazole derivative, triphenylamine derivative, 9-(P-diethylaminostyryl)anthracene,
], 1-bis(4-dibenzylaminophenyl)propane, styryl anthracene, styryl pyrazoline, phenylhydrazones, and α-stilbene derivatives.

Binder resins include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester,
Polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride,
Polyacrylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin,
Examples include thermoplastic or thermosetting resins such as urethane resins, phenol resins, and alkyd resins.

Solvents for forming the charge transport layer include tetrahydrofuran, dioxane, toluene, monochlorobenzene,
1,2-dichloroethane, cyclohexanone, methylene chloride, ], , l, 2-trichloroethane, 1.
1,2,2-tetrachloroethane and mixed solvents thereof are preferred. The thickness of the charge transport layer is 10 to 100. Preferably it is in the order of 20-40.

In the present invention, a lower arch layer can also be provided between the support and the photosensitive layer.

The undercoat layer is a thermoplastic resin such as polyamide, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, polyvinyl methyl ether, polyvinyl pyrrolidone, poly-N-vinylimidazole, ethyl cellulose, nitrocellulose, ethylene-acrylic acid copolymer, casein, gelatin, etc. Thermosetting resins such as phenol, urea resin, melamine, alkyd, unsaturated polyester, and epoxy, and these resins include titanium oxide, zinc oxide,
It is composed of dispersed inorganic raw materials such as indium oxide, antimony oxide, and tin oxide.

The solvents used here are cyclohexane, benzene, toluene, xylene, dichloromethane, ].

1-dichloroethane, 1,2-dichloroethane, 1,1
．． 2-trichloroethane, 1,1,2.2-tetrachloroethane, monochlorobenzene, methanol, ethanol, butanol, methyl ethyl ketene, methyl isobutyl ketone, methyl-〇-amyl ketone, methyl-〇-butyl ketone, diethyl ketone, methyl-〇 - Propyl ketone, cyclohexanone, methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethyl acetate, butyl acetate, dioxane, tetrahydrofuran and the like are preferred.

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

Further, in the present invention, a protective layer may be provided on the charge transport layer.

The protective layer is a layer in which ultrafine metal or metal oxide powder is dispersed in a binder resin. The binder resin is preferably one that is substantially transparent to visible and infrared light and has excellent electrical insulation, mechanical strength, and adhesive properties.

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, fluororesin, etc. Can be used. As the metal powder, gold, silver, aluminum, iron, copper, or nickel can be used, and as the metal oxide, zinc oxide, titanium oxide, tin oxide, bismuth oxide, antimony oxide, indium oxide, etc. can be used.

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

The thickness of the protective layer can be set between 0.5 and 30 tones as necessary.

Next, the coating apparatus used in the present invention will be explained according to the drawings.

FIG. 1 schematically shows the coating apparatus of the present invention.

In FIG. 1, the support 11 is held by a rotating shaft 13 and rotated in the direction of the arrow by the power of a motor 12.

The coating liquid 10 in the coating liquid tank 16 is passed through a filter 18, a flexible tube 15, and a pipe 25 by a pump 17.
, is supplied to the nozzle 14 via the valve 24. Nozzle 1
4 is fixed to the nozzle holding member 22 at the pipe 25, and is moved in the direction of the arrow along the slide bar 23 by the motor 2mm rotating the ball screw 2o.

Coating is performed by rotating the support 11 and discharging the coating liquid 1o through the nozzle 14 while moving the nozzle 14 in the direction of the arrow. Coating liquid] 0 means maximum surface roughness (Rmax) is 0
．． 3 to 1.5-, and the pitch is 0.2 to 0.
2+am spirally coated onto the support]1. The coating liquid position is indicated by a broken line.

When the support 11 is a cylindrical base with a radius r, the coating film thickness t
is given by the following equation (1).

W here ：Coating liquid solid content W: Coating liquid discharge amount C5: Nozzle movement speed r: support radius t: film thickness It is.

FIG. 2 is an enlarged view of the nozzle portion of the coating device used in FIG. 1. The coating liquid 16 is supplied to the pipe 25. The liquid is discharged from the nozzle 14 via the valve 24 and applied to the support 11. The nozzle 14 has a circular cross-sectional shape, and is made of a material that is not attacked by the solvent of the coating liquid 10, such as Teflon or stainless steel. The coating liquid 10 is applied to the support 11 while maintaining the nozzle 14 in a cylindrical shape with an inner diameter of 8 or more. For this purpose, the circumferential speed of the support 11 must be adjusted. must satisfy the following equation (2).

The distance g between the tip of the nozzle 14 and the support 11 is determined by the following formula (
It is desirable to satisfy 3).

g=□ d (C: constant) (3) Fig. 3 is an explanatory diagram of a spray gun used in a spray coating device, and the discharge amount of the coating liquid 10 is determined by the protrusion amount of the needle 28. It is controlled by adjusting the output amount adjustment knob 29 and the amount of liquid sent by the pump 17 shown in FIG. When spray coating,
The needle 28 is retracted into the spray nozzle by the gas pressure from the needle operation gas introduction pipe, and the coating liquid 0 and the gas from the carrier gas introduction pipe are blown out from the gap between the needle 28 and the nozzle portion 32.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Copolymerized nylon (CM8000, manufactured by Toshi) 24 g methanol (manufactured by Kanto Kagaku) 403.2i1-
Butanol (Kanto Chemical) 172.8g
1lliL of a subbing layer coating solution consisting of 1. Aluminum drum (outer diameter 80 mm, length 34 mm) with end face cut after I processing
0i+m, thickness 1mm, surface roughness Rmax O, 1/4
m) was subjected to dip coating to form a 0.31M undercoat layer, and then heated and dried at 110°C for 5 minutes.

On the other hand, a trisazo pigment (manufactured by Ricoh) with the following composition (lower EN): 12.5
A mixture of 2.1 g and 182.5 g of butyral resin (manufactured by XYHL UCC) and cyclohexanone (Kanto Kagaku M) was placed in a ball mill bot and milled with φl05LI.
After ball milling for 48 hours using an S ball, 300 g of cyclohexanone was further added and milling was carried out for 1 hour. After milling, the mill paste was taken out, diluted with cyclohexanone so that the solid content concentration was 1.8 vt%, and stirred to prepare a coating solution for forming a charge generation layer.

This coating solution was applied by dip coating in the same manner as the undercoat layer to form a charge generation layer with a thickness of 0.17 m, and then heated and dried at 130° C. for 10 minutes.

Next, a charge transport material having the following composition and the following formula (II) (manufactured by Ricoh Co., Ltd.) 8.5
g ・Silicone oil (KF-50 manufactured by Shin-Etsu Chemical Co., Ltd.)
A charge transport layer coating solution containing 127.2 g of 0.005 g 1,2-cyclohexanone (Kanto Kagaku H) was prepared, and the first
Using the coating apparatus shown in the figure and the circular nozzle shown in Fig. 2, a charge transport layer with a thickness of 25 mm was coated under the following coating conditions.
Heat drying was performed for 0 minutes.

<Charge transport layer coating conditions> ・Circular nozzle inner diameter φ0.2mm・
Nozzle-support distance 1: 3 mm・Support rotation speed: 75 rpm・Nozzle scan speed: 0.5+n+a/s・
Coating liquid discharge amount 1.34cc/1l
Number of in-scans: 1 Example 2 The charge generation layer forming coating solution used in Example 1 was applied by dip coating onto the aluminum drum used in Example 1 to form a charge generation layer with a film thickness of 0.1-. Afterwards, it was heated and dried at 130° C. for 10 minutes.

Next, a charge transport material with the following composition and the following formula (III) (Ricoh 31i) was used.
14.2g ・Polycarbonate resin (K-1300 manufactured by Teijin Chemicals) 15.8g ・Silicone oil (KF-50 manufactured by Shin-Etsu Chemical) 0.0
06g dichloromethane (Kanto Chemical Exhibition) 1
10g-1,1,2-trichloroethane (Kanto Chemical Exhibition)
110 g of charge transport layer coating solution was prepared, and a film thickness of 30 -
A charge transport layer of 1 was coated and dried by heating at 120° C. for 20 minutes.

<Charge transport layer coating conditions> ・Circular nozzle inner diameter φ0.3ms
+・Nozzle-support distance 2. .

・Support rotation speed 60rp■・
Nozzle scan speed 0.3mm/s
・Coating liquid discharge amount cc/win
・Number of scans: 1 Example 3 ・Titanium oxide (A-100 manufactured by Ishihara Sangyo) 1
60g Alkyd resin (Beccolito 6404-5
0-5 manufactured by Dainippon Ink) 32g ・Melamine resin (Super Beckamine L-117-60
(manufactured by Dainippon Ink) 17.8g
・Methyl ethyl ketone (Kanto Chemical Exhibition) 101.
A mixture consisting of 4 g was placed in a ball mill pot, and after ball milling for 24 hours using a φ10 alumina pole as a mill member, 155 g of methyl ethyl ketone was added.
6g was added and milled for 1 hour.

After milling, the mill base was taken out, diluted with methyl ethyl ketone to give a solid content concentration of 35 tst%, and stirred to prepare an undercoat layer coating solution.

This undercoat layer coating solution was applied by dip coating onto the aluminum drum used in Example 1, and the coating solution was coated with a coating solution of 0.5. After forming the subbing layer, it was heated and dried at 150° C. for 20 minutes.

A charge generation layer was provided on this undercoat layer in exactly the same manner as in Example 1.

Next, a charge transport material having the following composition and the following formula (IV) (manufactured by Ricoh) 8
．． 2g polycarbonate resin (K-1300, Ondai Kasei 1) 11
．． 8g silicone oil (KF-50, Shin-Etsu Chemical $1
A charge transport layer coating solution containing 180 g of 0.005 g of 1,2-dichloroethane (Kanto Chemical Exhibition) was prepared, and a charge transport layer with a thickness of 22 mm was coated under the following coating conditions. Heat drying was performed at ℃ for 20 minutes.

<Charge transport layer coating conditions> ・Circular nozzle inner diameter φ0.4m■
・Nozzle-support distance 3+++
m・Support rotation speed 67rp
m・Nozzle scan speed 0.7mm
Comparative Example 1 An undercoat layer and a charge generation layer were formed in exactly the same manner as in Example 1. Next, the following composition: 35 g of charge transport material (■) (manufactured by Ricoh), 50 g of polycarbonate resin (C-1400)
, manufactured by Ondai Kasei) ・Silicone oil (KF-50, manufactured by Shin-Etsu Chemical) 0
．． 01g・Methylene chloride (Kanto Chemical Exhibition)
415 g of a charge transport coating solution was prepared, and a charge transport layer of 25p11 was coated on the charge generation layer by dip coating.
Heat drying was performed at ℃ for 15 minutes.

Comparative Example 2 An undercoat layer and a charge generation layer were formed in exactly the same manner as in Example 3. Next, the following composition/charge transport material (■) (manufactured by Ricoh) 7
g. Silicone oil (KF-50, manufactured by Shin-Etsu Chemical) 0
．． 002g Tetrahydrofuran (Kanto Chemical) 83g
・Cyclohexanone (manufactured by Kanto Chemical) 150
A charge transport layer coating solution (g) was prepared, and spray coating was performed on the charge generation layer under the following conditions to coat a 22'4 charge transport layer, followed by heating and drying at 130° C. for 40 minutes.

・Spray pressure 1.5kg/c
d. Distance between support body and spray nozzle: 80m
m・Support rotation speed 60rp
■・Nozzle scan speed 5 鳳■/
S・Coating liquid discharge amount 19,3cc
/Company n/Number of scans: 5 Images of the photoreceptor thus prepared were evaluated using an electrostatic digital copying machine (Imagi No. 320, manufactured by Ricoh). Further, the maximum surface roughness in the longitudinal direction of the photosensitive layer was measured using Surfcom 550AD (manufactured by Tokyo Seimitsu Co., Ltd.). The results are shown in Table 1.

Table [Effects] As can be seen from the results in Table 1, the electrophotographic photoreceptor of the present invention has high sensitivity, does not generate abnormal images such as moiré, and can prevent toner filming, making it practical. It is extremely valuable.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the coating device used in the present invention, and the second
The figure is an enlarged explanatory diagram of the nozzle portion of the coating device used in the present invention, and FIG. 3 is an explanatory diagram of the spray gun used in the spray coating device. Patent Applicant Rico Co., Ltd. Attorney Patent Attorney Toshiaki Ikeura (and others) Figure 1 Figure 2 Figure 3 Figure 27: Nude Reno Z32: Nospar Suppression

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor comprising a photosensitive layer provided on a support, the photosensitive layer has a maximum surface roughness (Rmax) of 0.3
An electrophotographic photoreceptor characterized by being coated in a spiral shape with a pitch of 0.2 to 2 mm and a thickness of 1.5 μm.