JPS63311356A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain durability against abrasion and scratching of the surface of an uppermost resin layer due to friction by forming as the layer separated farthest from a base body the resin layer containing fluororesin particles dispersed into a fluorinated comb-type graft polymer as a dispersion medium. CONSTITUTION:The resin layer containing the fluorinated comb-type graft polymer containing the fluororesin particles dispersed into said polymer is formed in an electrophotographic sensitive body provided with a photosensitive layer on the conductive base body as the layer separated farthest from the base body. Said comb-type graft polymer is obtained by copolymerizing a macromonomer composed of an oligomer having a polymerizable functional group on one terminal of the molecular chain and a comparatively low molecular weight as low as 1,000-10,000 with a fluorinated polymerizable monomer and the obtained polymer has a structure in which each of the subpolymer units, especially, the macromonomer units hangs from the main chain in the form of a plate, thus permitting durability to be obtained against abrasion and scratching of the surface due to friction.

Description

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

[Conventional technology]

Electrophotographic photoreceptors are required to have the required sensitivity, electrical properties, and optical properties according to the electrophotographic process to which they are applied. The second surface layer, that is, the layer furthest from the substrate, is directly subjected to electrical and mechanical external forces such as corona charging, toner development, transfer to paper, and cleaning processing, so durability against these forces is required. Ru. in particular,
Durability is required against surface abrasion and texture due to rubbing, and surface deterioration due to ozone generated during corona charging in high humidity conditions. −10,000, toner development,
There is also a problem of toner adhesion to the surface layer due to repeated cleaning, and to solve this problem, it is required to improve the cleaning performance of the surface layer.

Various methods are being considered to satisfy the characteristics required for the surface layer as described above, but among them, the method of applying a resin layer containing dispersed fluororesin particles as a protective layer is effective. It is true. Dispersion of Teflon lowers the coefficient of friction of the surface layer, improving cleaning performance and durability against wear and texture. Furthermore, since the water repellency and mold releasability of the surface layer are improved, it is also effective in preventing surface deterioration under high humidity.

Further, since the protective layer is provided, the charge transporting material and the charge generating material, which are easily deteriorated by ozone, are isolated from the surface layer, and the durability is also improved. However, when dispersing fluororesin particles, there are problems with their dispersibility and agglomeration, making it difficult to form a uniform and smooth film. It was inevitable that the image would have defects. In addition, binder resins or dispersion aids with good dispersibility often cause deterioration of electrophotographic properties in most cases, and it is currently impossible to find anything effective.

[Problem that the invention seeks to solve]

The present invention seeks to provide an electrophotographic photoreceptor that meets the above requirements. That is, an object of the present invention is to provide an electrophotographic photoreceptor that is resistant to negative wear due to rubbing and generation of texture. Another object of the present invention is to provide a light body under high humidity. Another object of the invention is.

An object of the present invention is to provide an electrophotographic photoreceptor that has good cleaning properties and does not have toner attached to its surface. Furthermore, another object of the present invention is to provide an electrophotographic photoreceptor that is free from coating unevenness and pinholes on its surface, and which does not accumulate residual potential during repeated electrophotographic processes and can always provide high-quality images. It is in.

[Means for solving problems]

In accordance with this objective, the present inventors have made extensive studies and found that by providing a resin layer in which fluorine-based resin particles are dispersed using a fluorine-based comb-shaped graft 4 remer as a dispersion medium as the layer that is farthest from the substrate. The inventors have discovered that it is possible to provide an electrophotographic photoreceptor that meets the above-mentioned requirements, and have completed the present invention.

That is, the present invention provides an electrophotographic photoreceptor having a photosensitive layer on a conductive substrate, in which a resin layer containing a group of fluorine-based resin particles and a fluorine-based comb-shaped graft 4 reamer is provided as the layer furthest from the substrate. The present invention relates to an electrophotographic photoreceptor characterized by the following.

The fluororesin particle group used in the present invention includes tetrafluoroethylene resin, trifluorochloroethylene resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene dichloride difluoride resin, and It is desirable to appropriately select one or more copolymers from these copolymers, with tetrafluoroethylene resin and vinyldene fluoride resin being particularly preferred. The molecular weight of the resin and the particle size of the particles can be appropriately selected and are not particularly limited.

The fluorine-based comb-shaped graft polymer used in the present invention consists of a macromonomer consisting of a relatively low molecular weight oligomer having a polymerizable functional group at one end of each molecular chain and a fluorine-based It is obtained by copolymerizing polymerizable monomers, and has a structure in which macromonomer polymers are suspended like plates from a fluorine-based polymer as a backbone.

A macromonomer with which the resin to which the graft polymer is added has an affinity is selected, and for example, polymers or co-premers of acrylic esters, methacrylic esters, or styrene compounds are used.

On the other hand, as the fluorine-based polymerizable monomer, the following (1) to
One or more polymerizable monomers having a fluorine atom in the side chain such as (6) may be used, but the invention is not limited thereto.

CH2=C C-0CH2CF, (1) CH2=C-R1 C-NHCH20F, (2) 0M
2=C-R.

"0M2=CR4C-NHCH20M2CnF2n+,
(4) [In the formula, R1 represents a hydrogen atom or a methyl group.

R2 represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a nitrile group, and may be a combination of several types thereof. n is an integer of 1 or more, m is an integer of 1 to 5, k is an integer of 1 to 4
represents an integer of m + k == 5. ] The content of fluorine-based monomer residue in the fluorine-based comb-type graft polymer is preferably 5 to 90% by weight in the fluorine-based comb-type graft I remer, and 10 to 70% by weight.
% is more preferred. The content of fluorine monomer residue is 5
If the amount is less than -, the hydrophobic modification effect cannot be sufficiently exhibited, and if the content of fluoromonomer residue exceeds 90% by weight, the solubility with the macromonomer will deteriorate.

The presence of the fluorine-based graft polymer improves the dispersibility of the fluorine-based resin particles and prevents agglomeration during coating film formation, resulting in the formation of an extremely uniform and smooth Teflon dispersed layer. In addition, since the fluorine-based graft polymer has the above-mentioned structure, it has excellent compatibility with the coating solution containing the binder resin for forming the resin layer.
There is no migration or seepage above the 0 layer. Furthermore, there is no accumulation of residual charge due to repeated electrophotographic processes, and stable charging characteristics can be obtained. The content of the fluororesin particles to be dispersed is suitably 5 to 40% based on the solid content weight,
In particular, 10 to 30% is preferable. If the content is less than 5 inches, the modification effect due to the dispersion of the fluororesin particles will not be sufficient, while if it exceeds 40 inches, the light transmittance will decrease and the carrier mobility will also decrease. Also, the content of fluorine-based graft polymer is solid content! 0.01 to 10% is appropriate for tf, and especially KO, 05 to 2% is preferable. 0.01
If the particle size is less than 1, the effect of improving the dispersibility of the fluororesin particles will not be sufficient, while if it exceeds 10, the graft 4 remer will exist not only on the surface of the coating film but also in the bulk, which will affect the compatibility with the resin. This problem results in the accumulation of residual charges when repeated electrophotographic processes are performed. The binder resin for forming the resin layer may be any polymer that has film-forming properties, but polymethacrylate ester, polymethacrylate ester, Polycar? Preferred are nates, polyacrylates, -lyesters, 4-lysulfones, and the like.

When manufacturing the electrophotographic photoreceptor of the present invention, a metal such as aluminum or stainless steel, a cylindrical cylinder or a film made of paper, glass, or the like is used as the conductive substrate. A subbing layer (adhesive layer) having a barrier function and a subbing function can be provided on these substrates.

The undercoat layer is formed to improve adhesion of the photosensitive layer, improve coating properties, protect the substrate, cover defects on the substrate, improve charge injection from the substrate, protect the photosensitive layer from electrical breakdown, etc. Ru. Known materials for the undercoat layer include privinyl alcohol, -di-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid co-remer, casein, polyamide, copolymerized nylon, glue, gelatin, etc. It is being These are each dissolved in a suitable solvent and applied onto the substrate.

The film thickness is about 0.2 to 2μ.

A specific example of the photosensitive layer is a product of a charge generation layer containing a charge generation substance and a charge transport layer containing a charge transport substance.
The photosensitive layer includes a photosensitive layer having a structure, a photosensitive layer consisting of a single layer containing a charge generating substance and a charge transporting substance, and the like. Examples of charge generating substances include pyridium, thiopyrylium dyes, phthalocyanine pigments, anthoanthrone pigments, dibenzpyrenequinone pigments, -tenturone pigments, trisazo pigments, disazo pigments, azo pigments, indib9 pigments, quinacridone pigments, non-target quinocyanine, Quinocyanine and the like can be used. As the charge transport substance, pyrene, N-ethylcarbazole, N-isopropylcarbazole, N
-Methyl-N-phenylhydrazino-3-methylidene-
9-ethylcarbazole, NIJ-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N
-1'phenylhydrazino-3-methylidene-10-ditylphenothiazine, N,N-diphenylhydrazino-
3-methylidene-10-ditylphenoxazine, p-diethylaminobenzaldehyde N, N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-
α-naphthyl-N-phenylhydrazone, p-biarydinopenzaldehyde N, N-diphenylhydrazone,
1.3.3-) Hydrazone m, 2e5-his<p-diethylamino such as dimethylindolenine-ω-aldehyde-N,N-diphenylhydrazone, p-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone phenyl)-1,3,4-oxadiazole,
1-phenyl-3-(p-diethylaminostyryl)-
5-(p-diethylaminophenyl)pyrazoline, 1-
(quinolyl(2))-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2))-3-(p-diethylaminostyryl)-5-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, phenyl)
Pyrazoline, 1-(6-medoxyviridyl(2))-
3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(3
))-3-(p-diethylaminostyryl)-5-(p
-diethylaminophenyl)pyrazoline, 1-[levigil (2)) -3-(p-diethylaminostyryl)
-5-(p-diethylaminophenyl)pyrazoline, 1
-[pyridyl(2)]-3-(p-diethylaminostyryl)-4-methyl-5-(p-diethylaminophenyl)pyrazoline, 1-(pyridyl(2)) -3-(
α-Methyl-p-diethylaminostyryl)-5-(p
-diethylaminophenyl)pyrazoline, 1-phenyl-3-(p-diethylaminostyryl)-4-methyl-
5-(p-diethylaminophenyl)pyrazoline, 1-
Pyrazolines such as phenyl-3-(α-benzyl-p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline and spiropyrazoline, 2-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, spiropyrazoline,
-diethylaminostyryl)-6-dinithylaminobenzosol b2-(p-N ethylaminophenyl)
Oxazole compounds such as -4-(p-dimethylaminophenyl)-5-(2-chlorophenyl)oxazole% Thiazole compounds such as 2-(p-diethylaminostyryl)-6-dinithylaminobenzothiazole, bis(4 Triarylmethane derivatives such as -diethylamino-2-methylphenyl)-phenylmethane, 1,1-bis(4-N,N-diethylamine-2-methylphenyl)hegetane, 1,1.2.2- Tetrakis (4-N, N
Monoaryl alkanes such as -dimethylamino-2-methylphenyl)ethane and the like can be used.

An example of the aSS method for an electrophotographic photoreceptor of the present invention will be explained using a case of a functionally separated photosensitive layer in which a charge transport layer is laminated on a side farther from a substrate than a charge generation layer.

The above charge generating substance is mixed with a binder resin and a solvent in an amount of 0.3 to 10 times using a homogenizer, an ultrasonic wave, a ball mill,
Vibrating ball mill, sand mill, a)? It is well dispersed by methods such as rotary milling and roll milling.

This dispersion is applied onto the substrate coated with the undercoat layer and dried to form a coating film with a thickness of about 0.1 to 1 μm.

The charge transport layer is formed by dissolving the charge transport material and the binder resin in a solvent, and coating the mixture on the charge generation layer. The mixing ratio of the charge transport material and the binder resin is about 2:1 to 1:2. Examples of solvents include aromatic hydrocarbons such as toluene and xylene, dichloromethane, chlorobenzene, chloroform,
Chlorinated hydrocarbons such as carbonate are used.

When applying this solution, coating methods such as dip coating, spray coating, spinner coating, bead coating, grade coating, and curtain coating can be used, and drying is carried out at 10°C to 200°C. , preferably 20°C
5 minutes to 5 hours at a temperature in the range of ~150°C, preferably 1
The drying can be carried out for 0 minutes to 2 hours under blow drying or stationary drying. The thickness of the generated charge transport layer is 5 to 20
It is about μ. When coating a resin layer containing dispersed fluororesin particles and fluororesin comb-shaped graft 4 remer on this photosensitive layer, the fluororesin powder is dispersed in the binder resin, fluororesin particles and The 7-part system comb-shaped graft primer is dispersed together with a solvent using a method such as a homogenizer, ball mill, sand mill, attritor, or roll mill.

Next, this dispersion is applied onto the photoreceptor by a dip coating method, a spray coating method, a spinner coating method, a push-up coating method, a curtain coating method, or the like. Drying is performed under the same conditions as for the charge transport layer to form a resin layer having a thickness of 10 μm or less. or,
In order to facilitate the movement of charges, a charge transport substance may be added to the resin 1- in an amount lower than the concentration of the charge transport substance in the charge transport layer.

〔Example〕

The present invention will be explained below with reference to Examples.

Example 1 An aluminum cylinder of 80φ×36011 tl was used as a base. This is made of polyamide resin (product name: Amilan C).
A 54 methanol solution of M-8000 (manufactured by Toshi) was applied by dipping to form a 1 μm thick undercoat layer.

Next, add 10 parts (parts by weight, the same applies hereinafter) of the disazo pigment of the following structural formula to polyvinyl! 8 parts of Tyral resin (trade name: S-LEC BXL, manufactured by Kasui Kagaku ■) and 50 parts of cyclohexanone were dispersed for 20 hours in a sand mill apparatus using 1φ glass beads.

Add 70 to 120 methyl ethyl ketone (as appropriate) to this dispersion.
A charge generating layer having a thickness of 0.15 .mu.m was formed by coating the undercoat layer on the undercoat layer.

Next, 10 parts of a hydrazone compound with the following structural formula and bisphenol A type? Liquor is Nate (Product name: 9 Flight L)
1250 (manufactured by Teijin Kasei) was dissolved in 60 parts of dichloromethane and applied with S on the charge generating layer. Then 100℃
A charge transport layer having a thickness of 15 μm was formed by drying with hot air for 1 hour.

Next, the polycarbonate, 19 parts, 10 parts, poly47tethylene powder (trade name Nilpuron L-2, manufactured by Daikin Industries)
2 parts, the trunk is polyfluoroacrylate (CH2=:CH
COO-CH2CH2CuF2n+, electric combination, n=8
゜10.12.14 mixture), the branch has molecules l1t300
Fluorine-based comb-shaped graph dorimer (containing fluoroacrylate) with molecules 1so, ooo made of polystyrene with
0.12 parts of 50% by weight) were dispersed together with 50 parts of ditetramethane in a stainless steel M-lumil for 50 hours. This dispersion was applied onto the charge transport layer and dried with hot air at 100°C for 30 minutes to form a resin layer with a thickness of 3μ, and the surface roughness was 0.
It was 26μ.

This was designated as sample 1. For comparison, a sample without the fluorine-based comb-shaped graft 4 remer was prepared in the same manner as above, but many aggregates of polytetrafluoroethylene powder were generated due to poor dispersibility. The surface roughness was extremely poor at 7.8μ. This was designated as comparative sample 1. These photoreceptors were installed in a commercially available copier (NP-3525 manufactured by Canon 0),
Image evaluation of 50,000 sheets and durability evaluation were conducted. Table 1 shows the results.

Table 1 After the durability test, sample 1 was subjected to another 50,000 sheets of durability testing at high temperature and high humidity (32.5°C, relative humidity 90%), and high-quality images were stably obtained. .

Example 2 Bisphenol type 2-liquor nate (Mitsubishi Gas Chemical ■
(manufactured by Polyfluoroacrylate) (CH2-CHC00CH2CH2Cu')
2n+1 polymer, a mixture of n=x8, 10, 14) with branches made of polymethyl methacrylate with a molecular weight of 4500 and a fluorine-based comb-shaped Gra7 torimer with a molecular weight of 70,000 (fluoroacrylate content 30% by weight) 0. 21
'B 60 parts of monochlorobenzene! In step 4, stainless steel was dispersed in Lumil for 50 hours.

This dispersion was applied onto a drum coated with the charge transport layer in the same manner as in Example 1, and dried with hot air at 110°C for 45 minutes.
A resin layer of μ was formed. The surface roughness was 0.24μ. This was designated as sample 2. For comparison, a product without the addition of fluorine-based comb-shaped graph dorimer was prepared in the same manner as above, but due to poor dispersibility, many aggregates of poly(47)-modified tyrene powder were generated. The surface roughness is 8.5. μ
It was extremely bad. This will be referred to as comparative sample 2. These photoreceptors were used in a commercially available copying machine (Canon NP-3525).
50,000 images and durability were evaluated.

Table 2 shows the results.

Table 2 After the durability test, Sample 2 was subjected to a further test run of 50,000 sheets at high temperature and high humidity (32.5° C., relative humidity of 90 degrees Celsius), and high quality images were stably obtained.

Example 3 Polymethyl methacrylate (trade name DIANAL BR-
86 manufactured by Mitsubishi Rayon ■) 10 parts polytrifluorochlorinated ethylene (trade name: Guiflon manufactured by Daikin Industries ■) 3 parts, 0.2 parts of the fluorine-based comb-shaped Graff Dorimer used in Example 2, and 55 parts of monochlorobenzene. I taught for 50 hours using a stainless steel gale mill. This dispersion was applied onto a drum coated up to the charge transport layer in the same manner as in Example 1.
It was dried with hot air at 0° C. for 45 minutes to form a 3 μm resin layer. The surface roughness was 0.26μ. This was designated as sample 3.

For comparison, a sample with a resin layer consisting of only a polymethacrylate layer to which polytrifluorochloroethylene was not added was prepared in the same manner. The surface roughness was 0.28μ. This will be referred to as comparative sample 3.

These photoreceptors were used in a commercially available copier (Canon NP-35).
25), and 50,000 images were evaluated and durability was evaluated. Table 3 shows the results.

Table 3 Next, after durability test, Sample 3 was subjected to another 20,000 sheets of durability test at high temperature and high humidity (32.5° C., relative humidity 90%), and high quality images were stably obtained.

〔Effect of the invention〕

The electrophotographic photoreceptor of the present invention has durability against surface abrasion and scratches caused by rubbing, and can form stable high-quality images even under high humidity. Furthermore, the cleaning properties are good and there is no toner adhesion to the surface. Furthermore,
There is no coating unevenness or pinholes on the surface, and the residual potential is 1? High-quality images are always obtained without any interference.

Claims (6)

[Claims] (1) An electrophotographic photoreceptor having a photosensitive layer on a conductive substrate, characterized in that a resin layer containing a group of fluorine-based resin particles and a fluorine-based comb-shaped graft polymer is provided as the layer furthest away from the substrate. An electrophotographic photoreceptor. (2) The fluororesin particle group is a tetrafluoroethylene resin,
Consists of one or more resins selected from trifluorochloroethylene resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluoride dichloride ethylene resin, and copolymers thereof An electrophotographic photoreceptor according to claim (1). (3) The electrophotographic photoreceptor according to claim (1), wherein the photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer. (4) The electrophotographic photoreceptor according to claim (1), wherein the photosensitive layer comprises a single layer containing a charge-generating substance and a charge-transporting substance. (5) The content of fluororesin powder in the resin layer is 5 to 40
The electrophotographic photoreceptor according to claim (1), which is % by weight. (6) The electrophotographic photoreceptor according to claim (1), wherein the content of the fluorine-based comb-shaped graft polymer in the resin layer is 0.01 to 10% by weight.