JPH02875A - Production of protective layer of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve sensitivity and electrostatic chargeability by coating a compsn. contg. a tin oxide formed by adding water into a resin liquid incorporated with an org. tin compd. and/or a tin oxide contg. a hydroxyl group on the surface of the electrophotographic sensitive body and drying the coating to cure, thereby forming the protective layer. CONSTITUTION:The tin oxide obtd. by incorporating the org. tin compd. and a high-polymer compd. into a solvent and adding the water thereto and/or the tin oxide contg. the hydroxyl group is coated on the surface of the above- mentioned body and is dried to cure, by which the surface protective layer is formed. The protective layer is, therefore, the layer formed by dispersing the particles of Sn(II)3O2(OH)2 as an essential component into the binder of the high-polymer compd. The electrophotographic sensitive body which has the surface protective layer having excellent spectral transmittance and has the high durability (high wear resistance) while having the high sensitivity and high electrostatic chargeability is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an electrophotographic photoreceptor in which a photosensitive layer, an intermediate layer, and a surface protective layer are sequentially laminated on a conductive support.

[Prior Art] Conventionally, photoreceptors for electrophotography have been prepared by providing a photosensitive layer mainly made of selenium or a selenium alloy on a conductive support, or by disposing an inorganic photoconductive feed such as zinc oxide or cadmium oxide in a binder. Generally known are those using dispersed materials, those using organic photoconductive materials such as poly-N-vinylcarbazole and trinitrofluorenone or azo pigments, and those using amorphous silicon.

At present, Se-based photoreceptors, particularly 5e-As-based (As2Se3) photoreceptors, are known as the most sensitive electrophotographic photoreceptors, but these include the following problems.

■ Because the Se layer on the surface of the photoreceptor is exposed,
It is easily scratched by paper jams, etc. during actual use.

- Abnormal images such as background smudges and image deletion occur due to adsorption and contamination of special chemicals, etc., present in the copying machine (developer, cleaning member, etc.) or in the usage environment.

(2) Similarly, during actual use, there is a risk that the Se layer will be worn out due to friction from the paper, the cleaning section, the developing section, etc., and that Se will be diluted and discharged onto the copy.

(2) Particularly in the case of a 5e-As photoreceptor, the surface resistance is not sufficiently large immediately after vapor deposition, and the charging potential may be insufficient if left as is.

As a method for solving these drawbacks, a technique is known in which a protective layer is provided on the surface of the photoreceptor. Specifically, a method of providing an organic film on the surface of a photosensitive layer (Japanese Patent Publication No. 3G-1544)
13) Method of providing inorganic oxide (Japanese Patent Publication No. 43-14
517), a method of laminating an insulating layer after providing an adhesive layer (Japanese Patent Publication No. 43-27594), or plasma CVD
a-9i:H layer, a-3i
:N:H layer, a-3i:O:H layer, etc. method (JP-A-57-17911159, JP-A-59-51114)
37) has been disclosed.

However, the protective layer has a high electrophotographic resistance (to”Ω
・cm or more), problems such as an increase in residual potential and accumulation upon repeated use occur, which is not preferred in practice.

A method of using a photoconductive layer as a protective layer as a technique to compensate for the above drawbacks (Japanese Patent Publication No. 48-38427, Japanese Patent Publication No. 43-16198)
, Special Publication No. 49-10258, USP 2901
348 >, a method of adding a transfer agent such as a dye or a Lewis acid into the protective layer (Japanese Patent Publication No. 44-834, Japanese Patent Application Laid-open No. 1987-53)
-133444), or a method of controlling the resistance of a protective layer by adding metal or metal oxide fine particles (Japanese Patent Application Laid-open No. 1983-133-
3338) etc. have been proposed.

However, in such a case, light is absorbed by the protective layer and the amount of light reaching the photosensitive layer is reduced, resulting in a problem that the sensitivity of the photoreceptor is reduced (so-called filter effect).

Furthermore, as proposed in JP-A No. 57-30848, there is a method of making the protective layer substantially transparent to light by dispersing a metal oxide with an average particle size of 0.3 μm or less as a resistance control agent in the protective layer. However, in reality, there are many particles with a diameter of 0.3 μm or more, which causes absorption and scattering of visible light, reducing the sensitivity of the photoreceptor. Furthermore, a problem peculiar to photoreceptors having a protective layer containing fine particles dispersed therein is a decrease in resolution. Furthermore, there is a manufacturing technology problem of uniformly dispersing the fine particles in the resin, which also leads to an increase in costs. Ball mills and the like have traditionally been used as a dispersion method, but in the process of fine dispersion, contamination of media materials and containers due to scratches cannot be avoided, which also poses a problem in manufacturing technology.

As described above, a technology that can completely solve the above-mentioned problems (1) to (3) inherent in Se-based photoreceptors without causing side effects has not yet been completed.

[Objective] In view of the above-mentioned circumstances, it is an object of the present invention to provide a photoreceptor that eliminates such drawbacks, and in particular has a surface protective layer with excellent spectral transmittance and has a high spectral transmittance. sensitivity,
The object of the present invention is to provide an electrophotographic photoreceptor that is highly chargeable and highly durable (rich in abrasion resistance).

[Constitution] The present inventor contains an organic tin compound and a polymer compound in a solvent, and applies a solution containing a tin oxide and/or a tin oxide containing a hydroxyl group obtained by adding water to the solvent. However, it was discovered that a photoreceptor having a surface protective layer provided by drying and curing had excellent performance, and the present invention was developed.

That is, the present invention provides an electrophotographic photoreceptor in which a photosensitive layer, an interlayer, and a surface protective layer are sequentially laminated on a conductive support, in which the protective layer contains Sn as a main component in a polymer binder.
(II) It is characterized by being a layer in which particles of 302 (OH)2 are dispersed.

S n (II) 302 (01
1) 2 is a complex compound called tin oxide hydroxide, which is a divalent tin oxide and hydroxide. The present inventor found that this particle has excellent performance as a resistance control agent for a protective layer,
This led to the present invention. This compound is divalent tin acetylacetonate Sn (II) (C!Ia COCl+
2- COCl13 ) 2 (hereinafter referred to as S n (II
) a c a c 2) can be produced as fine particles in a solvent at room temperature.

Therefore, by generating particles in a solvent to obtain a dispersion,
Thereafter, a polymer compound serving as a binder may be added to form a protective layer coating solution. Also, S n (, II) (aca
c) The Sn (n) 302 (OH) 2 particles may be mixed into a solution containing a binding material and decomposed by adding water to obtain a dispersion of Sn (n) 302 (OH) 2 particles, which may be used as a protective layer coating solution.

The organic tin compound used in the present invention is divalent tin acetylacetonate (n) X:S n (II)
(CH3CO・CH2COCl+3) 2 Tetramethoxytin: Sn (OCH3)4, Tetraethoxytin: Sn (QC2H5)4, Tetraisoproxytin: Sn (QC)H7)4, Tetraisobutoxytin: Sn (OC4H9)4, etc.

Among these, a particularly preferred compound is tin acetylacetone (
II).

The polymer compound used in the present invention is an organic/inorganic polymer compound that is generally used as a material for a protective layer, but does not cause an increase in residual potential during repeated use in a copying machine, and has good resolution and sharpness. It is preferable to use a method that does not adversely affect the basic image.

According to the study results of the present inventors, the basic physical properties of the protective layer include light transmittance of 70% or more in the effective wavelength range, preferably 80% or more.
% or more, and the electrical resistivity is +09 to 10' Ω
”cm, preferred <IO'0-1012Ω'
It was confirmed that a good surface protective layer can be obtained if the thickness of cm is satisfied.

Specific examples that satisfy such conditions include general organic polymer compounds such as polystyrene, MMA,
n-BMA, polyamide, polyester, polyurethane, polycarbonate, polyvinyl formal,
Examples include polysilicone, polyvinyl acecool, polyvinyl butyral, ethyl cellulose, melamine resin, and copolymers thereof.

Among these, a particularly preferred organic polymer compound is a styrene-methyl methacrylate-acrylic acid-N-methylolacrylamide copolymer.

As a photosensitive layer, a-3i:H; a-3t:N:H, a-
3i: C:H; Se or alloy of Se and Te, As, etc.; ZnO, CdS.

Organic photosensitive materials in which inorganic particles such as CdSe are dispersed in a binder resin, such as polyvinyl carbazole, trinitrofluorenone, and a eutectic complex of thiapyrylium salt and polycarbonate, are used. This photosensitive layer may be a single layer, a laminate of a charge generation layer and a charge transport layer, or a laminate of two or more layers such as a laminate of photosensitive layers having different absorption wavelength regions. Note that the thickness of the photosensitive layer is 10 to 70 μm for a single layer type, preferably 15 to 208 μm, and 50 μm for the charge generation layer for a laminated type.
Appropriately, the thickness of the charge transport layer is 0 to 2 .mu.m and the thickness of the charge transport layer is 5 to 50 .mu.m.

In the present invention, Se-based photoreceptors are preferred. As long as the photosensitive layer contains Se, either a single layer or a stacked layer can be used. In addition, the formulation of the photosensitive layer is not particularly limited, and depending on the lamination method of the protective layer, the photosensitive layer may have to be kept at a high temperature (100°C or higher). (Tg)100℃
The above is desirable. For example, the Tg of As2Se3 is about 180°C, and As, 5e1- (0,3<
If y<0.5), Tg>100°C. The photosensitive layer is produced by a normal vacuum evaporation method, and the film thickness is IO~1
100 Lt, preferably 30-70 μm.

The intermediate layer is a layer for increasing the adhesion between the protective layer and the photosensitive layer, and keeping the charging ratio of 6:j between the protective layer and the photosensitive layer to prevent the charging potential from decreasing due to charge injection. Examples of materials for the intermediate layer having such functions include epoxy resin, polyester resin, polyamide resin, polystyrene resin, polyvinylidene chloride resin, polyvinyl acetate, polyvinyl chloride, acrylic resin, silicone resin, and fluorine resin. organic polymer compounds; trimethylmonomethoxysilane, γ-glycidoxypropyl trime! - Silane coupling agents such as xysilane and γ-methacryloxypropyltrimethoxysilane: Metal alkoxides such as titanium tetrabutoxide, aluminum tripropoxide, and zirconium tetrabutoxide; Metals such as titanium acetylacetonate and zirconium acetylacetonate As one type of acetylacetone complex, a polymer compound formed by combining two or more types can be used. The thickness of this intermediate layer is usually 10 μm or less, 1
Preferably it is 1 μm or less.

As the conductive support, a conductor or an insulator treated for conductivity is used, such as stainless steel, AI
, Ni, Fe, MO% Cu.

Metals or alloys such as Ti5Au; Al, Ag, Au on insulating substrates such as polyester, polycarbonate, polyimide, polyamide, polypropylene, glass, etc.
Examples include conductive treated paper, conductive polymer, etc., in which a thin film of a metal such as Pb or a conductive material such as In2O3, 5nOz is formed by a method such as vapor deposition. The shape of the conductive support is not particularly limited, and examples thereof include a plate shape, a drum shape, and an endless belt shape.

The photoreceptor of the present invention provided with such a surface protective layer has excellent spectral transmittance, and has excellent sensitivity, durability,
It has excellent weather resistance and stable and sufficient surface resistance immediately after the photoreceptor is manufactured. Clear copies without white streaks etc. can be obtained, and Se will not adhere to the copies.

Furthermore, the good properties of the Se-based photoreceptor are not impaired in any way.

Furthermore, even if the photoreceptor is directly touched, the Se-based photosensitive layer will not deteriorate due to crystallization or the like, making handling easier.

Example 1 A was deposited on an AI support by vacuum deposition according to the following procedure.
A S2Se3 photosensitive layer was deposited.

(Procedure) 1) An AI support drum of 80 mm φ x 340 mm 51 was washed with percrene (120° C.) for 2 minutes.

2) Next, 5 wL% Na 3 PO 4 aqueous solution (80 °C
) for 60 seconds and then washed twice with water.

3) Next, after drying the surface with 80° C. hot water, it was set in a vapor deposition machine and evacuated to 10-STorr.

4) Further, an As25ea alloy was vapor-deposited on the support for 35 minutes under conditions of a vapor deposition source temperature of 400° C. and a support temperature of 200° C. to obtain a photoreceptor with a film thickness of about 60 μm.

A liquid mixture consisting of 2 parts by weight of zirconium acetylacetone, 1 part by weight of γ-methacryloxypropyltrimethoxysilane, and 40 parts by weight of n-butanol was applied onto this photosensitive layer and dried to form an intermediate layer having a thickness of about 2,000 layers.

Next, styrene-methyl methacrylate-acrylic acid-
N-Methylolacrylamide [co-association ratio, 35/6
0/2/3(vt%)]220wt% solution solvent toluene/n-butanol-97l) 500 parts by weight and S
100 parts by weight of a 20 vt% solution of n(II)acac2 (solvent toluene/n-butanol-9/I) and 5 parts by weight of water were added and mixed and stirred for 15 minutes. The obtained solution is applied by depping coating onto the photoconductor provided with the intermediate layer.
The photoreceptor was dried and cured at 130° C. for 30 minutes to produce a photoreceptor having a surface protective layer (approximately 5 μm thick).

Comparative Example 1 10 parts by weight of tin oxide fine powder (manufactured by Mitsubishi Metals) and styrene
Same as Example 1 except that 50 parts by weight of methyl methacrylate-acrylic acid-N-methylolacrylamide copolymer (same as Example 1) and an appropriate amount of solvent were added and dispersed in a ball mill for 120 hours to prepare a coating solution. A photoreceptor was fabricated.

The electrostatic properties and spectral transmittance of the surface protective layer of Example 1 and Comparative Example 1 are shown in Table 1 and FIG. 1.

Table 1 Electrostatic Properties The Examples exhibited better electrostatic properties and spectral transmittance of the surface j-layer than the Comparative Examples.

Moreover, the IR absorption spectrum of the hydrolysis product of the present invention is shown in FIG. The spectrum of the example is clearly different from that of the comparative example.

Example 2 As2 with a thickness of 60μ was deposited on an AI support by vacuum evaporation method.
A 5ea photosensitive layer was formed to prepare a photoreceptor.

On this photosensitive layer, a mixed solution consisting of 2 parts by weight of zirconium acetylacetone, 1 part by weight of γ-methacryloxypropyltrimethoxysilane, and 40 parts by weight of n-butanol was applied and dried to form an intermediate layer with a thickness of about 2,000 layers. .

Next, styrene - methyl methacrylate - acrylic acid ~
N-methylolacrylamide [copolymerization ratio, 35/[i
0/ 1 /4 (wt%) 500 parts by weight of 320 wt% solution (solvent toluene/n-butanol-9/l) and 20 wt% solution of acetylacetone tin (II) (solvent toluene/n-butanol-9/l) to .

parts by weight and 7 parts by weight of water were added thereto and mixed and stirred at room temperature for 30 minutes.

The resulting dispersion was dip-coated onto a photoreceptor provided up to the intermediate layer, and dried and cured at 130 degrees for 30 minutes to produce a photoreceptor having a surface protective layer (approximately 5 μm).

Comparative Example 2 10 parts by weight of tin oxide fine powder (manufactured by Mitsubishi Metals) and styrene
50 parts by weight of methyl methacrylate-acrylic acid to N-methylolacrylamide copolymer (same as in Example 2) and an appropriate amount of solvent were added and dispersed in a ball mill for 120 hours to obtain a coating liquid.

A photoreceptor was produced in the same manner as in Example 2 except for this.

The electrostatic properties of Example 2 and Comparative Example 2 are shown in Table-2.

Figures 1 and 2 are graphs showing the spectral transmittance and IR absorption spectrum of the surface protective layers of Example 1 and Comparative Example 1.

FIG. 3 is a graph showing the X-ray diffraction pattern of the surface protective layer of Example 2.

Similar to Example 1, Example 2 exhibited better characteristics than Comparative Example 2 in terms of sensitivity and spectral transmittance of the surface protective layer.

Moreover, the X-ray diffraction pattern of the hydrolysis product of S n (II) a c a C2 is shown in FIG. The diffraction pattern shows that this dispersion is S n (II) 302 (O1+
)2.

[Effects] As is clear from the above description, the photoreceptor according to the present invention has a protective layer with excellent spectral ratio, and has excellent electrostatic properties such as high sensitivity and high chargeability. It is.

[Brief explanation of the drawing]

Claims (2)

[Claims] (1) In a method for producing a surface protective layer in an electrophotographic photoreceptor in which a photosensitive layer, an intermediate layer, and a surface protective layer are sequentially laminated on a conductive support, this protective layer is placed in a resin solution containing an organic tin compound. A method for producing the above-mentioned protective layer, characterized in that it is formed by adding water, applying a composition containing produced tin oxide or/and tin oxide containing a hydroxyl group, and drying and curing the composition. (2) In an electrophotographic photoreceptor in which a photosensitive layer, an intermediate layer, and a surface protective layer are sequentially laminated on a conductive support, the protective layer includes particles of Sn_3(II)O_2(OH)_2 in a polymer compound binder. An electrophotographic photoreceptor characterized by being a layer in which are dispersed.