JPH0362039A - Electrophotographic photoreceptor, image forming method using this electrophotographic photoreceptor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 with excellent image quality and durability.

[Conventional technology]

Since the discovery that certain organic compounds exhibit photoconductivity, a number of organic photoconductors have been developed. for example,
Organic photoconductive polymers such as poly-N-vinylcarbazole and polyvinylanthracene; low-molecular organic photoconductors such as carbazole, anthracene, pyrazolines, oxadiazoles, hydrazones, and polyarylalkane; phthalocyanine pigments; and azo pigments. Organic pigments and dyes such as cyanine dyes, polycyclic pigments, perylene pigments, indigo dyes, thioindigo dyes, and squaric acid methine dyes are known. In particular, organic pigments and dyes with photoconductivity are easier to synthesize than inorganic materials.
Moreover, the variety of options for selecting compounds that exhibit photoconductivity in an appropriate wavelength range has been expanded, and a large number of photoconductive organic pigments and dyes have been proposed. For example, US Pat. No. 4,356,243, US Pat. No. 4,359,513, US Pat. No. 4,390,611, US Pat.
No. 88119, No. 4702982, No. 47358
As disclosed in No. 82, No. 4743523, No. 4820602, etc., an azo pigment exhibiting photoconductivity is used as a charge generating substance in a photosensitive layer which is functionally separated into a charge generation layer and a charge transport layer. Electrophotographic photoreceptors are known.

Electrophotographic photoreceptors using such organic photoconductors can be produced by coating by appropriately selecting a binder, so it is possible to provide photoreceptors with extremely high productivity and at low cost. It has the advantage of being able to freely control the sensitive wavelength range.

Among them, a laminated photoreceptor is obtained by laminating a charge transport layer and a charge generation layer mainly composed of a charge generation material.
It has better residual potential, memory, repeatability, etc. than other single-layer photoreceptors, and is especially advantageous in improving sensitivity. In recent years, there has been a demand for the development of organic photoreceptors that have sensitivity, memory, repeatability, and durability equivalent to or higher than that of highly sensitive inorganic photoreceptors such as A-3E, CdS, and A-8I. . However, at present, there are still many unresolved problems in the development of organic photoreceptors with such high performance.

In order to solve these problems, recently Japanese Patent Application Publication No. 61171
No. 771 (corresponding USP 4,664,997), JP-A-62-67094, JP-A-61-239248
Publication No. (corresponding USP 4,728,592), JP-A-64
An electrophotographic photoreceptor using oxytitanium phthalocyanine having an absorption peak on the longer wavelength side of visible light as a charge generating material has been reported in Japanese Patent No. 17056 and the like.

Although these are highly sensitive as reported data, they have not been able to bring out sufficient characteristics for practical use.

The conventionally disclosed laminated photoreceptor has a charge generation layer in which oxytitanium phthalocyanine is dispersed in a binder as a charge generation material, and a charge transport layer in which a charge transport material is contained in the binder, which are laminated on a smooth conductive support. It has a structure. It has been found that transfer memory occurs when this laminated photoreceptor is used in an electrophotographic laser printer.

Generally, electrophotographic photoreceptors using organic photoconductors use negative primary charging. In the case of a laser printer, since exposure is performed on an electrophotographic photoreceptor by image scanning, development is performed by reversal development using negatively charged toner, and the toner is transferred to transfer paper using a positively charged transfer charge. After this,
After cleaning the residual toner on the electrophotographic photoreceptor, the electrostatic charge is removed if necessary, and the electrophotographic photoreceptor returns to primary charging again for repeated use.

In a normal copying machine, this problem does not occur because both the negative charge and the transfer charge are negative, but in a laser printer, the transfer charge is a positive charge, which is opposite to the characteristics of the electrophotographic photoreceptor, so there is no problem here. Problem has occurred.

Conventional electrophotographic photoreceptors using azo pigments receive electron injection, so the influence of positive charging on transfer charging memory is small. However, when oxytitanium phthalocyanine is used, transfer charge memory due to positive charging occurs due to electron injection from the conductive support. For this reason, in an electrophotographic photoreceptor in which a charge generation layer and a charge transport layer containing oxytitanium phthalocyanine are provided on an aluminum substrate, if it is subjected to transfer charging by positive charging, it will not function normally even if it is then subjected to primary charging by negative charging. Cannot hold potential.

In order to avoid this transfer memory problem, commercially available laser printers use a method that weakens the transfer charge intensity. However, with this method, when the resistance of the transfer paper increases under low humidity conditions, toner cannot be transferred, resulting in blank images. Furthermore, toner cannot be transferred to cardboard or OHP films, which have high resistance even under normal humidity.

[Problem that the invention seeks to solve]

An object of the present invention is to provide an electrophotographic photoreceptor using oxytitanium phthalocyanine that solves the above-mentioned drawbacks.

Another object of the present invention is to provide an electrophotographic photoreceptor that does not cause transfer memory.

A further object of the present invention is to provide an electrophotographic photoreceptor with high sensitivity and high image quality for laser printers that makes the most of the characteristics of oxytitanium phthalocyanine.

[Means for solving problems]

That is, the present invention is an electrophotographic photoreceptor characterized by having a resin layer, a charge generation layer containing oxytitanium phthalocyanine, and a charge transport layer in this order on a conductive support having a roughened surface.

In other words, the positively charged transfer charge memory is able to transfer oxytitanium phthalocyanine directly from metals and conductive substances because the layer containing oxytitanium phthalocyanine is placed on a conductive support with a roughened surface via a resin layer. Electron injection into the titanium phthalocyanine is prevented from occurring.

It is thought that negative charges induced by positive charging during transfer are accumulated at the interface between the layer containing oxytitanium phthalocyanine and the resin layer.

According to the electrophotographic photoreceptor having the structure of the present invention, negative charges accumulated at the interface between the layer containing oxytitanium phthalocyanine and the resin layer during secondary charging are efficiently dissipated by the roughened conductive support. This made it possible to significantly reduce the transfer charge memory by preventing electron injection from the conductive support.

By solving these problems, the electrophotographic photoreceptor of the present invention can provide a high-quality laser printer without transfer memory by using the high sensitivity of oxytitanium phthalocyanine.

The surface roughening state of the conductive support used in the present invention is preferably such that the ten-point average surface roughness Rz''c' is in the range of 0.5 μm or more and 1.5 μm or less. If it is less than 0.5 μm, the transfer memory becomes too thick. If the thickness exceeds 1.5 μm, image defects such as black spots are likely to occur.

When the conductive support is a metal base, the surface roughening method is to mirror-polish the metal surface and then roughen it by making fine grooves with a cutting tool, or to roughen the metal base by sandblasting. Examples include methods for converting

Aluminum is the most preferred metal substrate, but
Stainless steel, iron, copper, nickel, chromium, etc. can also be used.

Further, the conductive support may be one in which a conductive layer with controlled surface roughness is provided on a metal base. In this case, the metal substrate on which the conductive layer is provided may be an insulating substrate such as plastic or paper.

A conductive layer with controlled surface roughness can be created by, for example, mixing a conductive substance, a curable resin spherical powder, and a binder resin and dispersing the mixture using a sand mill, ball mill, attritor, etc., and applying a coating liquid onto a metal or insulating substrate. It can be formed by coating and drying.

Examples of the conductive substance used in the conductive layer include metal powders such as aluminum, tin, and silver, conductive pigments mainly composed of metal oxides such as carbon powder, titanium oxide, barium sulfate, zinc oxide, and tin oxide; Polyacetylene, polyphenylene oxide, polypyrrole, polythiophene and LiCj! 04, metal phthalocyanine (M-PC), polymers containing M-PC in the main chain, and I2. Substance doped with TCNQ (tetracyanoquinodimethane), -NH2, -CO
Oh.

Examples include substances in which metal ions are coordinated to a polymer having OH (polymer metal complex), quaternary ammonium salts, quaternary chlorinated polymers, and various ionic substances.

Examples of the curable spherical resin powder include silicone resin,
Melamine resin, urea resin, acrylic resin.

Examples include styrene resin powder.

The shape of the curable spherical resin powder is preferably a true sphere or an elliptical sphere.

The average particle diameter is preferably 0.6 μm or more and 6 μm or less, particularly 1 μm or more and 4 μm or less.

Further, the amount of the curable spherical resin powder added is 0.5 to 30% by weight, preferably 2 to 10% by weight, based on the total weight of the conductive layer. If the amount added is less than 0.5% by weight, it will not be sufficient to increase the sensitivity of the photoreceptor and prevent transfer memory, and if it is more than 30% by weight, image defects will occur.

Further, as the binder resin, for example, acrylic resin,
Methacrylic resin, phenolic resin, styrene resin, polyurethane resin, epoxy resin, alkyd resin, polyester resin, silicone resin.

Thermosetting resins such as melamine resins and copolymers thereof, and curable rubbers are suitable.

The thickness of the conductive layer is 5 to 100 μm, especially 10 to 508 μm.
A range of m is preferred.

Examples of the shape of the conductive support include a cylinder shape, a sheet shape, and a belt shape.

The surface roughness was measured using a universal surface profile measuring device (M made by Koita Institute).
The surface roughness is expressed by ten-point average roughness Rz (JISBO601).

The measurement conditions were as follows.

Measuring Lenz: 0.8mmH Magnification: 20 ■Magnification: 5000 The cylindrical sample was further rotated by 180 degrees in the axial direction at 3 locations: top, middle, and bottom, for a total of 6 locations at 3 locations: top, middle, and bottom. Measurements were taken at several locations, and the average value was taken as the measured value of the sample.

Next, the resin layer provided on the roughened conductive support will be explained.

Examples of the resin used in the resin layer include polyamide, (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon), polyurethane, polyvinyl alcohol, nitrocellulose resin,
Ethylene-acrylic acid copolymer resin, phenolic resin,
Examples include acrylic resin, polyester, and polyether.

The resin layer is prepared by dissolving the above-mentioned resin in a solvent, applying it onto the roughened metal substrate or the roughened conductive layer using a coating method such as a wire bar, doctor blade, dipping, spraying, etc., and drying it. It can be formed by

The ten-point average surface roughness Rz of the resin layer is preferably 0.3 μm or less. If it is larger than 0.3 μm, the charge generation layer coated thereon may become uneven, making it impossible to provide a uniform image.

The charge generating layer can be formed by dispersing the oxytitanium phthalocyanine charge generating material together with a suitable binder resin solution, coating and drying. In this case, the binder resin may also be used.

The structure of oxytitanium phthalocyanine is represented by

However, x,,x2. x3. x4 represents CI or Br, and n, m, and l are integers of 0 to 4.

Any crystal form of oxytitanium phthalocyanine may be used, but for example, the Bragg angle 2θ±0.2° in X-ray diffraction of Cu Ka is 9.0°, 14.2'2
Crystalline oxytitanium phthalocyanine has strong main peaks at 3.9° and 27.1', and Bragg angle 2θ ± 0.2° has the strongest peak at 27.3°, 7.1
The crystalline form of oxytitanium phthalocyanine having the second strongest peak at 10°C can be mentioned.

Next, the Bragg angle 2θ± in the X-ray diffraction of CuKa is
A specific production example of crystalline oxytitanium phthalocyanine having strong main peaks at 9.0', 14.2°, 23.9° and 27.1' is shown in Production Example 1. Production Example 2 shows a specific production example of crystalline oxytitanium phthalocyanine having the strongest peak at Bragg angle 2θ±0.2° of 27.3° and the second strongest peak at 7.10°.

[Production Example 1] In 100 g of α-chlornaphthalene, 5.0 g of O-phthalodinitrile and 2.0 g of titanium tetrachloride were heated and stirred at 200'C for 3 hours, and then cooled to 50°C to collect the precipitated crystals. After separation by filtration, a paste of dichlorotitanium phthalocyanine was obtained. Next, this was heated to 100°C with N, N
'-Washing with 100 ml of dimethylformamide under stirring,
Then 100mj of methanol at 60℃! Washing was repeated twice, followed by filtration. Further, the resulting paste was stirred in 100 ml of deionized water at 80° C. for 1 hour and filtered to obtain blue oxytitanium phthalocyanine crystals. Yield 4
．． 3g0 The elemental analysis values of this compound were as follows.

Elemental analysis value (C32Hla Ns TiO) CHN
CA' Calculated value (%) 66.68 2.80 19.4
4 0.00 Actual value (%) 66.50 2.
99 19.42 0.47 Next, the crystals were dissolved in 30 ml of concentrated sulfuric acid and added dropwise to 300 ml of deionized water at 20°C under stirring to cause reprecipitation. After filtration and thorough washing with water, the amorphous Oxytitanium phthalocyanine was obtained.

The X-ray diffraction pattern of this amorphous oxytitanium phthalocyanine is shown in FIG. 4.0 g of the amorphous oxytitanium phthalocyanine thus obtained was mixed with methanol 1
The mixture was suspended and stirred in 00ml at room temperature (22°C) for 8 hours, filtered, and dried under reduced pressure to obtain low-crystalline oxytitanium phthalocyanine.

Next, 50 ml of pinene was added to 2.0 g of this oxytitanium phthalocyanine, and a milling process was performed at room temperature (22° C.) for 20 hours with glass beads of 1 mm diameter.

The solid content was taken out from this dispersion, thoroughly washed with methanol and then water, and dried to obtain oxytitanium phthalocyanine crystals. The yield was 1°8go. The X-ray diffraction pattern of this oxytitanium phthalocyanine crystal is shown in FIG.

[Production Example 2] Amorphous oxytitanium phthalocyanine obtained by the same method as Production Example 1 4. 100 ml of methanol was added to Og, and the mixture was boiled for 30 hours with stirring, filtered, and dried under reduced pressure to obtain oxytitanium phthalocyanine crystals. Yield: 3.6 g The X-ray diffraction pattern of this oxytitanium phthalocyanine crystal is shown in FIG.

Note that the X-ray diffraction pattern was measured using Cu Ka rays under the following conditions.

Measuring equipment used: Rigaku Denki X-ray diffractometer RAD-A system deg.

Start angle (2θ): 3 deg.

Stop angle (2θ): 40 deg.

Divergence slit: 0.5 deg.

Scattering slit: 0.5 deg.

Receiving slit: 0.3 mm Examples of binder resins used in the curved monochromator include polyester resin,
Acrylic resin, polyvinyl carbazole resin, phenoxy resin, polycarbonate resin, polyvinyl butyral resin, polystyrene resin, polyvinyl acetate resin,
Polysulfone resins, polyarylate resins, vinylidene chloride/acrylonitrile copolymer resins, etc. are mainly used.

The charge transport layer is mainly formed by applying and drying a paint in which a charge transport material and a binder resin are dissolved in a solvent.

Examples of the charge transport material used include various triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triallylmethane compounds.

Further, as the binder resin, those mentioned above for the charge generation layer can be used.

The method for coating these charge generation layers and charge transport layers is as follows:
A dipping method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method, etc. can be used.

The thickness of the charge generation layer is 0.01 to 5 μm, preferably 0.01 to 5 μm.
The thickness of the charge transport layer is 5 to 4 μm.
0 μm, preferably in the range of 10 to 30 μm.

FIGS. 3 and 4 show the layer structure of the electrophotographic photoreceptor of the present invention. In FIG. 3, a resin layer 5, a charge generation layer 6, and a charge transport layer 7 are laminated on a roughened conductive support l. In this case, the conductive support l has a structure in which a conductive layer 3 containing hardening spherical resin powder 4 is provided on a metal or insulating base 2.
The conductive layer 4 has a roughened surface due to the inclusion of .

Further, in FIG. 4, the conductive support 1 has a roughened metal base surface.

Furthermore, in the present invention, a thin protective layer may be provided on the surface of the charge transport layer in order to protect the charge transport layer from external impact.

The electrophotographic photoreceptor of the present invention can be widely applied not only to laser beam printers but also to LED printers, ordinary electrophotographic copying machines, and other electrophotographic application fields.

Example-1 100 parts by weight of conductive titanium oxide powder (manufactured by Titanium Industries) (hereinafter, parts by weight are referred to as parts), 100 parts of titanium oxide powder (manufactured by Sakai Kogyo), phenolic resin (manufactured by Dainippon Ink Co., Ltd., Briophen) ), 0.02 parts of silicone surfactant (Toshi Silicone), and 20 parts of spherical silicone resin fine powder (polymethylsilsesquioxane, specific gravity 1.3, average particle size 1.2 μm) were mixed with 50 parts of methanol. , 50 parts of Methyl Celsolve in a solvent and then dispersed in a sand mill for 6 hours. This dispersion liquid is 30φX
It was applied by dipping onto a 260 mm aluminum cylinder and thermally cured for 150 minutes to form a conductive layer with a thickness of 20 μm.

The ten-point average surface roughness Rz of this conductive layer was 0.6 μm.

Next, copolymerized nylon resin (product name: Amilan CM800)
0, made by Toshi) and 8 parts of a copolymerized nylon resin (trade name Nidoresin EF-30T made by Teikoku Kagaku) were dissolved in a mixed solution of 60 parts of methanol and 40 parts of butanol, and the solution was applied by dip coating onto the conductive layer. , a resin layer with a thickness of 0.8 μm was formed.

The ten-point average surface roughness Rz of this resin layer was 0.1 μm.

Next, 10 parts of oxytitanium phthalocyanine from Production Example 1 and cellulose acetate butyrate resin (trade name: CAB-381) were added.
; Eastman chemotype) 6 parts and cyclohexanone 6
0 part was mixed with 20 parts using a sand mill machine using 1φ glass beads.
Spread out time. Add 100% of methyl ethyl ketone to this dispersion.
A charge generating layer having a thickness of 0.1 um was obtained by dip coating onto the resin layer and heating and drying at 100° C. for 10 minutes.

Next, 10 parts of a hydrazone compound having the following structural formula and a polycarbonate resin (trade name: Panlite L-1250: Teidai Kakai Co., Ltd.) were added.
) was dissolved in 80 parts of dichloromethane.

This solution was applied on the charge generation layer by dip coating at 100°C.
Hot air drying was performed for an hour to form a charge transport layer having a thickness of 208 parts, and an electrophotographic photoreceptor was manufactured.

This photoreceptor N0. laser printer (LBP-3)
(manufactured by X Canon) to measure potential and image.

Charge exposure was performed under the following conditions.

Primary charging: Gridded corona charger current -400μA Grid bias -690v Transfer charging: Corona charger +150μA exposure Two-semiconductor laser wavelength 780mm Light intensity 0.3μJ/crr
? Potential measurement was performed by measuring dark area potential and bright area potential at the developing device position.

Transfer memory (T, M,) is expressed as the difference between the dark area potential when no transfer charge is applied and the dark area potential after one transfer charge.

For image evaluation, solid white, solid black, and halftone images were taken to examine the image quality and the influence of transfer memory.

Regarding ghosts, a 5 cm black vertical line was output on white, and then a half tone was output to examine the influence of the vertical line.

The results are shown in Table 1.

Example 2 Photoreceptor N002 was produced in the same manner as in Example 1, except that the amount of the spherical silicone resin fine powder used in the conductive layer was changed from 20 parts to 24 parts. Potential measurement and image production were performed in the same manner as in Example 1. Table 1 shows the results.
Shown below.

Example 3 Photoreceptor N003 was produced in the same manner as in Example 1, except that the amount of the spherical silicone resin fine powder used in the conductive layer was changed from 20 parts to 28 parts. Potential measurement and image production were performed in the same manner as in Example 1. Table 1 shows the results.
Shown below.

Example 4 Same as Example 1 except that the average particle size of the spherical silicone resin fine powder used for the conductive layer in Example 1 was changed from 1.2 μm to 2.0 μm and the amount added was changed from 20 parts to 10 parts. Photoreceptor No. 4 was manufactured. Potential measurement and image production were performed in the same manner as in Example 1. The results are shown in Table 1.

Example 5 Photoreceptor N was prepared in the same manner as in Example 1, except that the average particle diameter of the spherical silicone resin fine powder used for the conductive layer in Example 1 was changed from 1.2 μm to 2.0 μm, and the amount added was 20 parts.
0.5 was produced. Potential measurement and image output were performed in Example 1.
I did the same thing. The results are shown in Table 1.

Example 6 Photoreceptor N was prepared in the same manner as in Example 1, except that the average particle size of the spherical silicone resin fine powder used in the conductive layer in Example 1 was changed from 1.2 μm to 4.0 μm, and the amount added was 20 parts.
0.6 was produced. Potential measurement and image output were performed in Example 1.
I did the same thing. The results are shown in Table 1.

Comparative Example 1 Mirror polished aluminum cylinder, 30φX260
A cylinder of mm was obtained. The ten-point average surface roughness Rz of the aluminum cylinder was 0.1 μm. A charge generation layer and a charge transport layer were provided on this aluminum cylinder in the same manner as in Example 1 to produce photoreceptor No. 7. Potential measurement and image production were performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 Mirror polished aluminum cylinder, 30φX260
A cylinder of mm was obtained. Furthermore, the surface was roughened by sandblasting. The ten-point average surface roughness Rz of the aluminum cylinder was 1.5 μm. A charge generation layer and a charge transport layer were provided on this aluminum cylinder in the same manner as in Example 1 to produce photoreceptor No. 8.

Potential measurement and image production were performed in the same manner as in Example 1.

The results are shown in Table 1.

Comparative Example 3 Photoreceptor No. 9 was produced in the same manner as in Example 1, except that the spherical silicone resin fine powder used for the conductive layer in Example 1 was not added. Potential measurement and image production were performed in the same manner as in Example 1. The results are shown in Table 1.

As is clear from Examples 1 to 6 and Comparative Examples 1 to 3 in Table 1, the electrophotographic photoreceptor of the present invention has high image quality, is significantly less affected by transfer charging, and does not cause image defects typical of laser printers. Recognize.

Example 7 Mirror-polished aluminum cylinder, 30φX260
A cylinder of mm was obtained. Furthermore, the surface was roughened by sandblasting. The ten-point average surface roughness Rz of the aluminum cylinder was 0.8 μm. A resin layer was provided on this aluminum cylinder in the same manner as in Example 1. The ten-point average surface roughness Rz of this resin layer was 0.2 μm. Further, a charge generation layer and a charge transport layer were provided as in Example 1,
Photoreceptor No. 0.10 was manufactured. Potential measurement and image production were performed in the same manner as in Example 1. The results are shown in Table 2.

Example 8 Mirror polished aluminum cylinder, 30φX 26
A cylinder of 0 mm was obtained. Furthermore, the surface was roughened by sandblasting. The ten-point average surface roughness Rz of the aluminum cylinder was 1.0 μm. A resin layer was provided on this aluminum cylinder in the same manner as in Example 1. The ten-point average surface roughness Rz of this resin layer was 0.2 μm.

Further, a charge generation layer and a charge transport layer were provided in the same manner as in Example 1, and photoreceptor No. 11 was manufactured. Potential measurement and image production were performed in the same manner as in Example 1. The results are shown in Table 2.

Example 9 Mirror-polished aluminum cylinder, 30φX260
A cylinder of mm was obtained. Furthermore, the surface was roughened by sandblasting. The ten-point average surface roughness Rz of the aluminum cylinder was 1.2 μm. A resin layer was provided on this aluminum cylinder in the same manner as in Example 1. The ten-point average surface roughness Rz of this resin layer was 0.3 μm. Further, a charge generation layer and a charge transport layer were provided as in Example 1,
Photoreceptor No. 12 was manufactured. Potential measurement and image production were performed in the same manner as in Example 1. The results are shown in Table 2.

Example 10 Mirror polished aluminum cylinder, 30φX 26
A cylinder of 0 mm was obtained. Furthermore, the surface was roughened by sandblasting. The ten-point average surface roughness Rz of the aluminum cylinder was 1.5 μm. A resin layer was provided on this aluminum cylinder in the same manner as in Example 1. The ten-point average surface roughness Rz of this resin layer was 0.3 μm.

Further, a charge generation layer and a charge transport layer were provided in the same manner as in Example 1, and photoreceptor No. 13 was manufactured. Potential measurement and image production were performed in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 4 Mirror polished aluminum cylinder, 30φX260
A cylinder of mm was obtained. The ten-point average surface roughness Rz of the aluminum cylinder was 0.1 μm. A resin layer was provided on this aluminum cylinder in the same manner as in Example 1. The ten-point average surface roughness Rz of this resin layer was 0.1 μm. Further, a charge generation layer and a charge transport layer were provided in the same manner as in Example 1 to produce photoreceptor No. 14. Potential measurement and image production were performed in the same manner as in Example 1. The results are shown in Table 2.

As can be seen from Examples 7 to 1O and Comparative Example 4 in Table 2, the electrophotographic photoreceptor of the present invention has high image quality, is significantly less affected by transfer charging, and does not suffer from image defects typical of laser printers.

Example 11 100 parts of conductive titanium oxide powder (manufactured by Titan Kogyo), 100 parts of titanium oxide powder (manufactured by Sakai Kogyo), 125 parts of phenol resin (manufactured by Dainippon Ink Co., Ltd., Bleiofen), silicone surfactant (manufactured by Toshiba Co., Ltd.) 0.02 parts of silicone) and 15 parts of spherical melamine resin fine powder (melamine-formaldehyde copolymer, specific gravity 1.4, average particle size 3.0 μm) were mixed in a solvent of 50 parts of methanol and 50 parts of methylcellosolve, Then, the mixture was dispersed for 6 hours using a sand mill. This dispersion liquid was applied by dipping onto an aluminum cylinder of 30 φ x 260 mm to form a conductive layer with a thickness of 20 μm. The ten-point average surface roughness Rz of this conductive layer was 0.8 μm.

Next, 10 parts of nitrocellulose (manufactured by Daicel Chemical Industries, Ltd.) was dissolved in 100 parts of isopropyl alcohol, and the solution was dip coated onto the conductive layer to form a 0.7 μm thick resin layer. The ten-point average surface roughness Rz of this resin layer was 0.2 μm.

Next, 10 parts of oxytitanium phthalocyanine from Production Example 2, 6 parts of cellulose acetate butyrate resin (trade name: CAB-381; Eastman chemical type), and 60 parts of cyclohexanone were dispersed for 200 hours in a sand mill apparatus using 1φ glass beads. . 100 parts of methyl edyl ketone was added to this dispersion, and the mixture was dip coated onto the resin layer and dried by heating at 100° C. for 10 minutes to form a charge generating layer with a coating weight of 0.1 μm.

Next, 10 parts of a hydrazone compound having the following structural formula and a polycarbonate resin (trade name: Panlite L-1250: Teijin Chemicals Ltd.)
15 parts were dissolved in 80 parts of dichloromethane. This liquid was dip-coated onto the charge generation layer and dried with hot air at 100° C. for 1 hour to form a charge transport layer with a thickness of 20 μm, thereby producing photoreceptor No. 15.

This photoreceptor N0.15 is printed on a laser printer (L, BP).
-8X (manufactured by Canon) for potential measurement and image generation. -Next charging and transfer charging were carried out under the same conditions as in Example 1,
The exposure conditions were changed to a light amount of 0.9 μJlcrd.

The results are shown in Table 3.

Example 12 Photoreceptor No. 16 was produced in the same manner as in Example 11, except that the amount of the spherical melamine resin fine powder used in the conductive layer was changed from 15 parts to 20 parts. Potential measurement and image display were performed in the same manner as in Example 11. The results are shown in Table 3.

Example 13 Photoreceptor No. 17 was produced in the same manner as in Example 11, except that the amount of the spherical melamine resin fine powder used in the conductive layer was changed from 15 parts to 25 parts. Potential measurement and image display were performed in the same manner as in Example 11. The results are shown in Table 3.

Comparative Example 5 Mirror polished aluminum cylinder, 30φX260
A cylinder of mm was obtained. The ten-point average surface roughness Rz of the aluminum cylinder was 0.1 μm. A charge generation layer and a charge transport layer were provided on this aluminum cylinder in the same manner as in Example 11 to produce photoreceptor No. 0.18. Potential measurement and image production were performed in the same manner as in Example 11. The results are shown in Table 3.

As can be seen from Examples 11-13 and Comparative Example 5 in Table 3, the electrophotographic photoreceptor of the present invention has high image quality, is significantly less affected by transfer charging, and does not suffer from image defects typical of laser printers.

〔Effect of the invention〕

As described above, according to the present invention, high-quality images can be obtained without creating transfer memory.

[Brief explanation of drawings]

Figures 1 and 2 are X-ray diffraction spectra of oxytitanium phthalocyanine obtained in production examples of the present invention, and Figures 3 and 4 are schematic diagrams showing the layer structure of the electrophotographic photoreceptor of the present invention. figure.

Claims (2)

[Claims] (1) An electrophotographic photoreceptor comprising a resin layer, a charge generation layer containing oxytitanium phthalocyanine, and a charge transport layer in this order on a conductive support having a roughened surface. (2) Ten-point average surface roughness Rz 0.5 μm or more 1.5 μm
Ten point average surface roughness Rz0.3μ on the following conductive support
2. The electrophotographic photoreceptor according to claim 1, wherein the resin layer has a thickness of m or less.