JPH02191964A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve moisture resistance and wear resistance and to lower residual potential by constituting a surface protective layer of nylon copolymer of a ternary or higher system contg. 6 nylon and 66 nylon having <=10% satd. water absorptivity at 24 deg.C and 65% RH. CONSTITUTION:A photoconductive layer 12 and the surface protective layer 13 are successively laminated on a conductive base 11 to form the electrophotographic sensitive body 1. The surface protective layer is formed by dissolving the nylon copolymer of the ternary or higher system contg. the 6 nylon and 66 nylon having <=10% satd. water absorptivity at 24 deg.C and 65% RH in an solvent and applying the soln. on the photoconductive layer. The coating is hardened by self-condensation when heated. A hardener, such as melamine resin, is added to the soln. to improve the wear resistance and electrophotographic characteristics. Further, alumina, etc., are added and dispersed to and in the soln. to suppress the residual potential as far as possible. The thickness of the surface protective layer 13 is selected at 0.5 to 5mum and the ruggedness on the surface is selected at 0.03 to 0.30mum center line average height. The protective film which is improved in the durability is obtd. without impairing the image grade by this constitution.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an electrophotographic photoreceptor.

[Prior Art] Conventionally, electrophotographic photoreceptors have been known that are formed by sequentially laminating a photoconductive layer and a surface protective layer on a conductive support. If the photoconductive layer is exposed, the surface protective layer prevents the photoreceptor's functionality from deteriorating due to ozone (03) and nitrogen oxides (NOx) generated by rubbing during cleaning or corona discharge. For example, JP-A-57-204559 discloses an electrophotographic photoreceptor in which a surface protective layer made of an insulating resin containing polyesteramide is provided on a photoconductive layer.

The polyester amide constituting this surface protective layer is a copolymer of ester units (I> or (II) below and amide units (I [I) or (lV)), and the copolymerization ratio is ester /amide-20/80 to 85/15.

The following margin +C-+CH2-)-N H'r- Also, in consideration of wear resistance during printing, stability of electrostatic properties, etc., the surface protective layer is made of ceramics such as AQ 203, ZrO2, amorphous carbon, etc. , those made of metal-based materials are known.

[Problems to be Solved by the Invention] However, although the polyesteramide used in the surface protective layer is soluble in solvents because its crystallization is suppressed, it is still insufficient for coating operations. Furthermore, since it contains an ester component, it has the disadvantage that it lacks moisture resistance and abrasion resistance, and is prone to image deletion and scraping. In addition, since it contains an ester component, it has a high electrical resistance and a residual potential tends to accumulate, which tends to cause fogging and image unevenness after long-term use.

Furthermore, those in which the surface protective layer is made of ceramic or metal materials have poor adhesion to the photoconductive layer and tend to crack easily, making it impossible to obtain sufficient printing durability.

The present invention was devised in view of the above circumstances, and its object is to improve durability without impairing image quality by improving moisture resistance and abrasion resistance and reducing residual potential. An object of the present invention is to provide an electrophotographic photoreceptor having a surface protective layer that can protect the surface of the photoreceptor.

Means for Solving the Problem 1 An electrophotographic photoreceptor according to the first invention is an electrophotographic photoreceptor comprising a photoconductive layer and a surface protective layer sequentially laminated on a conductive support. The surface protective layer is characterized by being composed of a ternary or higher copolymerized nylon containing at least 6-nylon and 66-nylon components and having a saturated water absorption rate of 10% or less at 24° C. and 65% relative humidity. be.

The copolymerized nylon constituting the surface protective layer is a ternary or higher copolymerized nylon containing nylon 6 and nylon 66 that has at least the following repeating units and has a saturated water absorption rate of 10% or less at 24°C and 65% relative humidity. Nylon 6/
It is expressed as 66/L/M...

Nylon 6 -Co (CH2) s Nt-1-Nylon 66 -Co (CH2)4 C0NH(CH2
)6NH- In addition, as repeating units of copolymerized nylons other than nylon 6 and nylon 66, the following are mainly used as repeating units.

Nylon 610 -Co (CH2)a C0NH(C
H2) (, NH- Nylon 11 -(CH2> 100ONH Nylon 1
2-(CH2)11CONH-nylon 7-(
CH2)c C0NH-nylon 9-(CH2)dayC0NH=bis(4-aminocyclohexyl)methane-
〇The above copolymerized nylon is made by copolymerizing three or more types of nylons, including at least nylon 6 and nylon 66, to remove alcohols, chloroform, and DMF that cannot be obtained with homonylons such as nylon 6 and nylon 66.
, it becomes easily soluble in highly polar solvents such as water, and its hygroscopicity also decreases. In addition, transparency can be improved by reducing crystallinity, making it ideal as a photoreceptor surface layer and having excellent coating properties.

Copolymerized nylon 6/66/L/M... takes into account the solubility, hygroscopicity, and electrophotographic properties of the solvent used, and contains side chains, functional groups such as hydroxyl groups, aromatic rings, and It may also include a node ring, etc.

In addition, copolymerized nylon has a saturated water absorption rate (measured by JIS K6810: polyamide resin (nylon) molding test method) at 24°C relative humidity 65% of 0.5 to 10%, preferably 40°C relative humidity 65%. The saturated water absorption rate at 1.
0 to 8% is preferable.

If it is more than 10%, image deletion tends to occur, and if it is less than 0.5%, the residual potential becomes high and background fog tends to appear.

The surface protective layer is formed by dissolving the copolymerized nylon in a solvent and coating it on the photoconductive layer.In order to improve the abrasion resistance and electrophotographic properties of the surface protective layer, the copolymerized nylon is crosslinked. A curing agent such as melamine resin, epoxy resin, isocyanate resin, etc. that causes reaction may be added to the coating liquid.

However, if heated, even copolymerized nylon alone will self-condense and harden.

Furthermore, if it is desired to suppress the residual potential as much as possible from the viewpoint of an electrophotographic system, a surface protective layer may be formed by adding and dispersing the following inorganic powder for adjusting electrical resistance to the copolymerized nylon. For example, alumina, zirconia, ittria, spinel (MqO-ANz03), mullite (3A, ll
203.2SiO2), titania, silicon carbide, magnesium carbide, zinc oxide, silicon nitride, tungsten carbide, boron nitride, and the like.

In addition, methods for forming the surface protective layer include dip coating method, spray coating method, spinner coating method, blade coating method, roller coating method,
Various coating methods can be used, such as wire bar coating methods.

The thickness of the surface protective layer is 0.1 to 10 μm, preferably 0.
．． It is preferable to form the layer with a thickness of 5 to 5 μm. If it is thinner than 0.1 μm, the strength of the film will decrease and the photoconductive layer will be easily damaged. 1
If it is thicker than 0 μm, the light transmittance decreases, making it impossible to effectively guide irradiated light into the photoconductive layer, resulting in a decrease in sensitivity and an increase in residual potential.

The photoconductive layer is made of Se, 5e-AS alloy, 5e-Te alloy,
Inorganic photoconductive materials such as CdS, ZnO, and a-3i and organic photoconductive materials such as polyvinylcarbazole (PVK), phthalocyanine, trinitrofluorenone (TNF), dizuazo pigments, and hydrazone are deposited or dispersed in a binder resin. It may be a single-layer structure, a functionally separated structure in which a charge transport layer and a charge generation layer are laminated, or a structure other than these.

An electrophotographic system according to a second aspect of the invention is an electrophotographic photoreceptor in which a photoconductive layer and a surface protective layer are sequentially laminated on a conductive support, wherein the surface protective layer is on the photoconductive layer side. The saturated water absorption rate at 24℃ and 65% relative humidity is 10.
% or less of at least 6 nylon and 66 nylon components;
The first layer is laminated with a second layer made of an inorganic compound.

The first layer of the surface protective layer according to the second invention can be the same as the surface protective layer according to the first invention. However, the thickness of the first layer is 0.05 to 2.0 μm, preferably 0.05 to 2.0 μm.
The thickness is preferably 1 to 1.0 μm. If it is thinner than 0.05 μm, pinholes and coating gaps will occur, resulting in decreased adhesive strength and poor durability. On the other hand, if it is thicker than 2.0 μm, the residual potential tends to increase, and when the second layer is laminated, the surface hardness decreases due to the influence of the first layer.

The inorganic compounds constituting the second layer are ZrO2,5i02,
TiO2, Ta205, CeO2, Aj! Oxides of metals such as 203 or similar elements, S i N, Cr
The second layer preferably has a volume resistivity of 10<9>Ω·Cm or more, such as a nitride such as N1BN or a carbide such as SiC.

If it is less than that, charging in the electrophotographic process will not be sufficient and it will not be suitable as a material for protecting the surface of a photoreceptor. This second layer is formed using PV, for example, a vacuum evaporation method, a sputtering method, a plasma CVD method, etc.
It can be formed by D method or CVD method. After formation,
It is also possible to perform heat treatment.

An electrophotographic photoreceptor according to a third aspect of the invention is an electrophotographic photoreceptor comprising a photoconductive layer and a surface protective layer sequentially laminated on a conductive support, wherein the surface protective layer is formed at a relative humidity of 24° C. It is composed of ternary or higher copolymerized nylon containing at least 6-nylon and 66-nylon components with a saturated water absorption rate of 10% or less at 65%, and the surface has a centerline average roughness of 0.
It has an uneven portion of 0.03 to 0.30 μm.

That is, the present invention provides an electrophotographic photoreceptor according to the first invention, in which the surface protective layer has a centerline average roughness of 0.03 to 0.
．． It has an uneven portion of 30 μm.

These uneven portions can be formed by roughening the surface of the surface protective layer by direct grinding treatment or by roughening the surface of the photoconductive layer in advance before forming the surface protective layer. can. As the abrasive grain for grinding when performing the grinding process, for example, a single substance or a mixture of alumina, zirconium, diamond, titania, tungsten, carbide, etc. can be used. Further, the grinding process can be performed using a grinding machine or the like using a grinding wheel in which the abrasive grains are hardened with a binder. The size of the grinding abrasive grains is #800 to #4
000 is preferable and can be selected depending on the relationship with the film thickness of the surface protection diagram.

The center line average roughness due to the uneven parts of the surface protective layer is 0°03~
0.3OL1m, preferably 0.040~O.

The range is preferably 10 μm. If the thickness is less than 0803 μm, the durability of the surface protective layer or cleaning material may deteriorate due to an increase in frictional force, and the cleaning blade may easily warp. Further, if the diameter is 0°30 μm or more, clogging of the toner paper powder and wiping residue are likely to occur. Note that the centerline average roughness here refers to the centerline average roughness (Ra) according to JIS-8-0601.

An electrophotographic photoreceptor according to a fourth aspect of the present invention is an electrophotographic photoreceptor comprising a photoconductive layer and a surface protective layer sequentially laminated on a conductive support, wherein the surface protective layer is formed on the photoconductive layer. It is formed on the side and has a saturated water absorption rate of 10 at 24℃ and relative humidity of 65%.
% or less of at least 6 nylon and 66 nylon components;
A second layer made of an inorganic compound is laminated on the first layer, and the surface thereof has a center line average roughness of 0.03 to 0°30.
It has irregularities of μm.

That is, in the present invention, for the electrophotographic photoreceptor according to the second invention, the surface protective layer has a centerline average roughness of 0.03 to 0.
．． It has an uneven portion of 30 μm. This uneven portion can be formed similarly to that of the third invention.

[Example] The present invention will be explained in detail below.

(Example 1) The electrophotographic photoreceptor 1 of this example is related to the first invention, and as shown in a cross-sectional view in FIG. and a surface protective layer 13. The conductive support 11 is made of cylindrical aluminum. The photoconductive layer 12 is formed by forming amorphous arsenic selenide on the conductive support 11 to a thickness of 50 to 55 μm in a vacuum chamber at 10''5 Torr using a known vacuum deposition apparatus. The surface protective layer 13 is formed by dissolving a copolymerized nylon 6/66/12 resin (manufactured by Toshi Co., Ltd. [AQ-Nylon-80>) in a mixed solvent of methanol/toluene/water to form a paint, and applying the dipping method to the photoconductive layer. 12
It was formed by applying the film to a thickness of 1.5 μm and drying it at 130° C. for 10 minutes. The volume resistivity of this surface protective layer 13 was measured and found to be 1Q13Ω·cm. Further, the saturated water absorption rate of the copolymerized nylon used at 24° C. and 65% relative humidity was 2%.

(Example 2) The electrophotographic photoreceptor of this example differs from that of Example 1 only in the photoconductive layer and the surface protection layer. The photoconductive layer has a two-layer structure consisting of a charge generation layer formed on the conductive support side and a charge transport layer formed on the surface side.

The charge generation layer is formed as follows.

(Material composition) α-type copper phthalocyanine of the following structural formula (A) (Wako fil
30 parts by weight polycarbonate resin (manufactured by Teijin Chemicals! IL-1225J)
100 parts by weight trichloroethane
20 parts by weight (A>α-type copper phthalocyanine)
After dispersing for a minute, the mixture was diluted with trichloroethane, applied by a dipping method, and dried to form a charge generation layer with a thickness of 0.3 μm.

Further, the charge transport layer is formed as follows.

(Material composition) 80 parts by weight of a hydrazone compound of the following structural formula (B) acrylic polyol resin (rLR-1 manufactured by Mitsubishi Rayon Co., Ltd.)
503J) 100 parts by weight Toluene/methyl ethyl ketone mixed solvent 80 parts by weight (B) Hydrazone compound (N-ethylcarbazole-N
-Methyl-N-phenylhydrazone) 2 H5 This composition material was stirred for 30 minutes using Daysilver, and after dissolving the hydrazone, 2 parts by weight of an isocyanate curing agent ("Coronate L" manufactured by Nippon Polyurethane Co., Ltd.) was added, and this was mixed using the dipping method. After coating, it was dried at 120° C. for 30 minutes to form a charge transport layer with a thickness of 16 μm.

The surface protective layer is made by dissolving copolymerized nylon 6/66/bis(4-aminocyclohexyl)methane-6 (BAS Ultraamide IC) in a mixed solvent of methanol/DMF/water to form a coating with a resin solid content of 15%. %), to which 20% by weight of melamine resin (Sumimar M-40SJ manufactured by Sumitomo Chemical Co., Ltd.) was added and coated by a spray method to form a thickness of 2.0 μm. The volume resistivity of the surface protective layer was 1Q11 Ω·am.The saturated moisture absorption rate of the copolymerized nylon used at 24° C. and 65% relative humidity was 1.5%.

(Example 3) The electrophotographic photoreceptor of this example differs from that of Example 1 only in the surface protective layer. This surface protective layer is made of copolymerized nylon 6/66/12 (rAQ-nylon manufactured by Toshi Co., Ltd.).
0J) was dissolved in a mixed solution of methanol/toluene/water to make a 15% by weight solution, and 20% by weight of solid content was added to this solution.
Epoxy resin (Dinacol EX61 manufactured by Nagase Sangyo Co., Ltd.)
4BJ)/Melamine resin (rT34J manufactured by Mitsui Toatsu Co., Ltd.)
A curing agent having a composition of 4/1 was added, applied by a dipping method, and then dried and cured at 130° C. for 1 hour.2.
It is formed to have a thickness of 5 μm. The volume resistivity of this surface protective layer was 1011 Ω·cm. Further, the saturated water absorption rate of the copolymerized nylon used at 24° C. and 65% relative humidity was 2%.

(Example 4) The electrophotographic photoreceptor 2 of this example is related to the second invention, and as shown in a cross-sectional view in FIG. and the first layer 231 and the second layer 231
and a surface protection 1123 consisting of a layer 232. The conductive support 21 and the photoconductive layer 22 are formed in the same manner as in Example 1. The first layer 231 of the surface protection layer 23 was formed in the same manner as the surface protection layer of Example 1, except that its thickness was 0.5 μm. The second layer 232 is formed using a 15 MH2 high frequency sputtering device in an atmosphere of He gas Q and 1 torr.
was formed to a thickness of 0.5 μm.

(Example 5) The electrophotographic photoreceptor of this example is composed of a conductive support, a photoconductive layer, and a surface protective layer consisting of a first layer and a second layer. A second layer is added to the material. The second layer was made with 1.0% TiO2 by vacuum evaporation method.
It is formed to a thickness of μm.

(Example 6) The electrophotographic photoreceptor of this example is composed of a conductive support, a photoconductive layer, and a surface protection layer consisting of a first layer and a second layer, and is different from that of Example 4. Only the surface protective layer is different. The first layer of the surface protection layer is made by dissolving copolymerized nylon 6/66/12 in a mixed solvent of methanol/toluene/water to form a 3% solution, and adding 20% by weight of epoxy resin/solids to this solution. A curing agent of melamine resin = 4/1 was added, and after coating by dipping, it was dried and cured at 130'C for 1 hour to form a thickness of 0.5 μm.

The second layer is made of SiC formed to a thickness of 0.5 μm using a 15 MH 2 high frequency sputtering device in an atmosphere of He gas O and 1 torr.

(Example 7) The electrophotographic photoreceptor of this example is composed of a conductive support, a photoconductive layer, and a surface protective layer consisting of a first layer and a second layer, and is the same as that of the sixth example. The only difference is the surface protective layer.

The first layer of the surface protection layer is copolymerized nylon 6/66/61.
0 resin (90 in rAQ nylon manufactured by Toshi Co., Ltd.) was dissolved in a mixed solvent of methanol/diacetone alcohol/water to obtain 1.
A 5% by weight solution was prepared, and a 20% by weight epoxy resin (manufactured by Nagase Sangyo Co., Ltd. [Dinacol EX614BJ) was added to this solution.
)/Melamine resin (Mitsui Toatsu rT-34J) = 4/1 hardening agent was added, applied by dipping method, dried at 150°C for 1 hour to cure, and formed into a thickness of 0.5 μm. has been done.

Then, the second layer was formed by applying a substrate voltage of 200 V using an arc discharge type ion blating device and forming a film at a deposition rate of 10 mu/min.
SeC, substrate temperature kept at 60℃, AQ203 0.8μ
It is formed to a thickness of m.

(Example 8) The electrophotographic photoreceptor 3 of this example is related to the third invention, and as shown in a cross-sectional view in FIG. and a surface protective layer 33 having uneven portions 33a on its surface. This electrophotographic photoreceptor 3 differs from that of Example 1 in that the surface protection layer 33 has uneven portions 33a. The uneven portion 33a is
The surface of the surface protection layer 33 was polished using a cylindrical grinder (Kondo Seisakusho R)-1i using a #2000 diamond abrasive grindstone.
-GI oss450-HJ) grinding wheel circumferential speed 110
It is formed by grinding at a pitch of 0Q/min.

The centerline average roughness (Ra) of the surface protective layer 33 thus obtained was 0.048 μm. The volume resistivity of the surface protective layer 33 was 1Q13Ω·Cm, and the saturated water absorption rate of the copolymerized nylon used at 24° C. and 65% relative humidity was 2%.

(Example 9) The electrophotographic photoreceptor of this example is one according to the third invention comprising a conductive support, a photoconductive layer, and a surface protective layer having an uneven surface. This example differs from Example 2 only in that the protective layer has an uneven portion. The uneven portions of the surface protective layer were similarly formed using the cylindrical grinder of Example 8 using a #1000 titania grindstone. The center line average roughness (Ra) of this surface protective layer was 0.067 μm. In addition, the volume resistivity of the surface protective layer is 1013 Ω·cm,
The saturated water absorption rate of the copolymerized nylon used at 24° C. and 65% relative humidity was 1.5%.

(Example 10) The electrophotographic photoreceptor of this example is one according to the third invention comprising a conductive support, a photoconductive layer, and a surface protective layer having an uneven surface. This example differs from Example 3 only in that the protective layer has an uneven portion. The uneven portion of the surface protective layer was formed in the same manner as in Example 8, and the centerline average roughness (Ra) of the surface protective layer was 0.040 μm.

The volume resistivity of this surface protective layer is 1011Ω・cm
The relative humidity of the copolymerized nylon used at 24°C is 65
The saturated water absorption rate in % was 2%.

(Example 11) The electrophotographic photoreceptor 4 of this example is related to the third invention, and as shown in a cross-sectional view in FIG. The photoconductive layer 42 includes a photoconductive layer 42 and a surface protective layer 43 having an uneven surface 43a. When forming the electrophotographic photoreceptor of Example 1, this electrophotographic photoreceptor 4 is obtained by forming a photoconductive layer 42 and then grinding the photoconductive layer 42 to roughen the surface, thereby forming a surface protective layer. 43 with an uneven portion 43a.

The surface of the photoconductive layer 42 was ground in the same manner as in Example 8. The centerline average roughness (Ra) of the surface protective layer 43 thus obtained was 0.048 μm. The volume resistivity of this surface protective layer 43 was 1011 Ω·cm, and the saturated water absorption rate of the copolymerized nylon used at 24° C. and 65% relative humidity was 2%.

(Example 12) The electrophotographic photoreceptor 4 of this example is related to the third invention, and includes a conductive support, a photoconductive layer with a roughened surface, and an uneven portion on the surface. and a surface protective layer. When forming the electrophotographic photoreceptor of Example 2, this electrophotographic photoreceptor was formed by forming a photoconductive layer and then grinding the photoconductive layer to roughen the surface, thereby creating uneven portions in the surface protective layer. was formed. The surface of the photoconductive layer was ground in the same manner as in Example 9. The center line average roughness (Ra) of the surface protective layer thus obtained was 0°067 μm. Note that the volume resistivity of this surface protective layer is 1011
Ω·cm, and the saturated water absorption rate of the copolymerized nylon used at 24° C. and 65% relative humidity was 1.5%.

(Example 13) The electrophotographic photoreceptor of this example is related to the third invention, and has a conductive support, a photoconductive layer with a roughened surface, and an uneven portion on the surface. It consists of a surface protective layer. When forming the electrophotographic photoreceptor of Example 3, this electrophotographic photoreceptor was formed by forming a photoconductive layer and then grinding the photoconductive layer to roughen the surface, thereby creating uneven portions in the surface protective layer. was formed. The surface of the photoconductive layer was ground in the same manner as in Example 8. The centerline average roughness (Ra) of the surface protective layer thus obtained was 0.040 μm. The volume resistivity of this surface protective layer is 1011Ω.
・cm, and the saturated water absorption rate of the copolymerized nylon used at 24° C. and 65% relative humidity was 2%.

(Example 14) The electrophotographic photoreceptor 5 of this example is related to the fourth invention, and as shown in a cross-sectional view in FIG. photoconductive layer 52 and the first
Consisting of a layer 531 and a second layer 532, the surface has an uneven portion 53.
The surface protective layer 53 has a. This electrophotographic photoreceptor 5 is manufactured by forming the photoconductive layer 52 after forming the photoconductive layer 52 when forming the electrophotographic photoreceptor of Example 4.
2 is ground to roughen the surface, thereby forming an uneven portion 53a on the surface protective layer 53. The surface of the photoconductive layer 52 was ground in the same manner as in Example 8. The centerline average roughness (Ra) of the surface protective layer 53 thus obtained was 0.095 μm. The volume resistivity of this surface protective layer 53 is 1013 Ω·cm, and the saturated water absorption rate of the copolymerized nylon used at 24° C. and 65% relative humidity is 2%.
Met.

(Example 15) The electrophotographic photoreceptor of this example is related to the fourth invention, and includes a conductive support, a photoconductive layer with a roughened surface, a first layer and a second layer. It is composed of a surface protective layer and a surface protective layer having an uneven surface. When forming the electrophotographic photoreceptor of Example 5, this electrophotographic photoreceptor was produced by forming a photoconductive layer and then grinding the photoconductive layer to roughen the surface, thereby creating uneven portions in the surface protective layer. was formed. The surface of the photoconductive layer was ground in the same manner as in Example 9.

Center line average roughness of the surface protective layer obtained in this way (
Ra) was 0.088 μm.

The volume resistivity of this surface protective layer is 101]Ω・cm
The relative humidity of the copolymerized nylon used at 24°C is 65
The saturated water absorption rate in % was 1.5%.

(Example 16) The electrophotographic photoreceptor of this example is related to the fourth invention, and includes a conductive support, a photoconductive layer with a roughened surface, a first layer and a second layer. It is composed of a surface protective layer and a surface protective layer having an uneven surface. When forming the electrophotographic photoreceptor of Example 6, this electrophotographic photoreceptor was produced by forming a photoconductive layer and then grinding the photoconductive layer to roughen the surface. was formed. The surface of the photoconductive layer was ground in the same manner as in Example 8.

Center line average roughness of the surface protective layer obtained in this way (
Ra) was 0.092 μm.

The volume resistivity of this surface protective layer is 1011Ω・cm
The relative humidity of the copolymerized nylon used at 24°C is 65
The saturated water absorption rate in % was 2%.

(Example 17) The electrophotographic photoreceptor of this example is related to the fourth invention, and includes a conductive support, a photoconductive layer with a roughened surface, a first layer and a second layer. It is composed of a surface protective layer and a surface protective layer having an uneven surface. When forming the electrophotographic photoreceptor of Example 7, this electrophotographic photoreceptor was formed by forming a photoconductive layer and then grinding the photoconductive layer to roughen the surface. was formed. The surface of the photoconductive layer was ground in the same manner as in Example 8.

Center line average roughness of the surface protective layer obtained in this way (
Ra> was 0.078 μm.

The volume resistivity of this surface protective layer is 1011Ω・cm
The relative humidity of the copolymerized nylon used at 24°C is 65
The saturated water absorption rate in % was 2%.

(Comparative Example 1) This comparative example differs from that of Example 1 described above only in the surface protective layer, and is a conventional example using polyesteramide.

That is, this surface protective layer is made of polybutylene ethylene terephthalate 5.
A polyesteramide obtained by copolymerizing 50 parts by weight of fi and 50 parts by weight of undecane amide was dissolved in dimethylformamide/methanol (=1/3) to make a 10% by weight solution, which was applied by dipping and dried to a thickness of 2 μm. It is formed.

(Comparative Example 2) This comparative example differs from that of Example 2 above only in the surface protective layer, and is a conventional example using polyesteramide.

This surface protective layer was made by dissolving polyesteramide, which is a copolymerization of 50 parts by weight of polyisophthalate and 50 parts by weight of dodecane amide, in trichloroethane/methanol (=115) to make a 12% by weight solution, which was applied by a spray method and dried. It is formed to have a thickness of 3 μm.

(Test) The electrophotographic photoreceptors produced in Examples 1 to 17 and Comparative Examples 1 and 2 above were installed in an actual copying machine (a modified EP-550 machine manufactured by Minolta Camera Co., Ltd.), and a comparative test of the performance thereof was conducted. I did it. This test can be used for positive or negative corona charging.
A conventional electrophotographic process consisting of exposure, development, transfer/separation, and erasure was carried out, and the charging potential, residual potential, image quality, film thickness reduction, and initial rotational torque of the electrophotographic photoreceptor were measured. In addition, in this test, the charging potential, residual potential,
The image quality was measured at the initial stage and after 200,000 printings, and the amount of film thickness reduction (μm) was measured after 200,000 printings. Table 1 diagrammatically shows the configurations of Examples 1 to 17 and Comparative Examples 1 and 2, and Table 2 shows the measurement results.

Note that, among the measurement items, regarding the image quality, a circle mark indicates good quality, a Δ mark indicates a slight decrease, and an X mark indicates a decrease.

As shown in Table 2, in the electrophotographic photoreceptors of Comparative Examples 1 and 2, the charge potential increased by 70 to 90 V after printing 200,000 sheets.
The accumulation of residual potential was also as large as 60 to 70V.

Further, regarding the image quality after printing 200,000 sheets, image blurring occurred and a decrease in quality was observed. The decrease in film thickness was 1.4 μm or more in all cases, and the wear resistance was not good.

On the other hand, it was confirmed that the electrophotographic photoreceptors of Examples 1 to 17 had stable charge potentials even after printing 200,000 sheets, and the accumulation of residual potential was small (30 V or less). In general, no image bleeding was observed in the actual evaluation after printing 200,000 copies, confirming that the film had excellent moisture resistance. Further, the amount of decrease in film thickness was very small, 0.82 μm or less, and it was confirmed that the film had excellent wear resistance after printing. In particular, Examples 4 to 7.
Samples Nos. 14 to 17 in which the surface protective layer had a two-layer structure were extremely good. Furthermore, it was confirmed that the initial rotational torque was reduced to 6.4 kg·cm or less.

In addition, regarding this initial rotational torque, even if the composition and structure of the electrophotographic photoreceptor are the same, if the outermost surface is uneven with Ra = 0.03 to 0.3 μm, the torque will be reduced. In particular, Examples 4 to 7 and 14 to 17, in which the outermost surface was made of an inorganic material and had an uneven shape, showed low values on the order of 4 kO-Cm.

From the above results, it was confirmed that the electrophotographic photoreceptor provided with the surface protective layer according to the present invention can improve durability without impairing image quality.

[Effects of the Invention] In the electrophotographic photoreceptor according to the first invention, the surface protective layer is composed of at least 6-nylon and 66-nylon components having a saturated water absorption rate of 10% or less at 24° C. and 65% relative humidity. It is composed of copolymerized nylon with a higher grade than the original type. Therefore, it is possible to improve moisture resistance and abrasion resistance, and to reduce residual potential. Therefore,
Durability can be improved without impairing image quality. Further, the copolymerized nylon used in the present invention is soluble in organic solvents and has excellent coating properties.

In the electrophotographic photoreceptor according to the second invention, the surface protective layer is formed on the photoconductive layer side and is heated at 24° C. relative humidity 65° C.
A first layer made of a ternary or higher copolymerized nylon containing at least 6-nylon and 66-nylon components with a saturated water absorption rate of 10% or less, and a second layer laminated on the first layer and made of an inorganic compound. It is made up of. Therefore, in addition to improving moisture resistance and abrasion resistance and reducing residual potential, the first layer can prevent cracks from occurring in the second layer, making it more durable. Printing performance can be further improved.

Further, in the electrophotographic photoreceptor according to the third invention, compared to the electrophotography photoreceptor according to the first invention, the surface protective layer has unevenness with a center line average roughness of 0.03 to 0°30 μm. It has a section. Therefore, the durability can be further improved, and the abrasion resistance is particularly good due to the uneven portion, and the initial rotational torque of the electrophotographic photoreceptor can be reduced.

Further, in the electrophotographic photoreceptor according to the fourth invention, compared to the electrophotographic photoreceptor according to the second invention, the surface protective layer has unevenness with a center line average roughness of 0.03 to 0°30 μm. Since the electrophotographic photoreceptor has a portion, the durability can be further improved, and the initial rotational torque of the electrophotographic photoreceptor can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electrophotographic photoreceptor according to Example 1 of the first invention. FIG. 2 is a sectional view of an electrophotographic photoreceptor according to Example 4 of the second invention. FIG. 3 is a sectional view of an electrophotographic photoreceptor according to Example 8 of the third invention. FIG. 4 is a sectional view of an electrophotographic photoreceptor according to Example 11 of the third invention. FIG. 5 is a sectional view of an electrophotographic photoreceptor according to Example 14 of the fourth invention. 1.2.3.4.5...Electrophotographic photoreceptor 11.21
．． 31.41.51...Electroconductive support 12.22.3
2.42.52...Photoconductive layer 13.23.33.43
．． 53...Surface protective layer 231.531...First layer 232.532...Second layer 33a, 43a, 53a...Irregularities

Claims (4)

[Claims] (1) In an electrophotographic photoreceptor formed by sequentially laminating a photoconductive layer and a surface protective layer on a conductive support, the surface protective layer has a saturated water absorption rate of 10% at 24° C. and 65% relative humidity. An electrophotographic photoreceptor characterized in that it is composed of a ternary or higher copolymerized nylon containing at least the following 6-nylon and 66-nylon components. (2) In an electrophotographic photoreceptor in which a photoconductive layer and a surface protective layer are sequentially laminated on a conductive support, the surface protective layer is formed on the photoconductive layer side at 24° C. and 65% relative humidity.
A first layer made of a ternary or higher copolymerized nylon containing at least nylon 6 and nylon 66 having a saturated water absorption rate of 10% or less, and a second layer laminated on the first layer and made of an inorganic compound. A photoreceptor for electrophotography, characterized in that: (3) In an electrophotographic photoreceptor formed by sequentially laminating a photoconductive layer and a surface protective layer on a conductive support, the surface protective layer has a saturated water absorption rate of 10% at 24° C. and 65% relative humidity. An electronic device consisting of a ternary or higher copolymerized nylon containing at least the following 6-nylon and 66-nylon components, and having unevenness on its surface with a center line average roughness of 0.03 to 0.30 μm. Photographic photoreceptor. (4) In an electrophotographic photoreceptor in which a photoconductive layer and a surface protective layer are sequentially laminated on a conductive support, the surface protective layer is formed on the photoconductive layer side at 24° C. and 65% relative humidity.
A first layer made of a ternary or higher copolymerized nylon containing at least nylon 6 and nylon 66 having a saturated water absorption rate of 10% or less, and a second layer laminated on the first layer and made of an inorganic compound. 1. A photoreceptor for electrophotography, characterized in that the surface thereof has uneven portions having a center line average roughness of 0.03 to 0.30 μm.