JPH0267562A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obviate the surface fixing of a developer such as toner and to obtain a sharp copied image free from scumming even after repeated use by specifying the concn. of the residual solvent in a charge transfer layer. CONSTITUTION:The concn. of the residual solvent in the charge transfer layer is confined to <=5,000ppm. The toner and developer, etc., are liable to stick to the surface of the charge transfer layer and the copied image is scummed if the concn. of the residual solvent contained in the charge transfer layer is >=5,000ppm. The charge transfer layer is formed by dissolving a charge transfer material and resin binder in a suitable org. solvent, applying the soln. on a charge generating layer in such a manner that the concn. of the residual solvent attains <=5,000ppm and drying the coating. Poly-N-vinyl carbazole and the deriv. thereof, etc., are used as the charge transfer material and tetrahydrofuran, etc., are used as the org. solvent. Polystyrene, etc., are used as the resin binder. The surface fixing of the developer such as toner is obviated in this way and the sharp copied image which is free from scumming even after the repeated use is obtd.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improvements in electrophotographic photoreceptors.

[Conventional technology]

Conventionally, as a means for preventing toner developer from sticking to the electrophotographic photoreceptor that occurs during the electrophotographic process, for example, a method of adding additives to the surface layer (Japanese Patent Laid-Open No. 62-2
23757), a method of mechanically polishing the surface (Japanese Unexamined Patent Publication No. 5
5-050286) and the like are known.

However, the former method has drawbacks such as poor compatibility between the additives used and the binder resin, resulting in cloudiness and adversely affecting the electrostatic properties of electrophotography; This has the disadvantage that not only the adhered substances but also the photosensitive layer itself is abraded.

[Problem to be solved by the invention]

The present invention has been made in view of the above-mentioned circumstances of the prior art, and its purpose is to provide an electrophotographic photographic system that prevents developer such as toner from sticking to the surface and that can be used repeatedly to produce clear reproduced images without background smudges. The purpose of the present invention is to provide a photoreceptor for

[Means to solve the problem]

According to the present invention, in an electrophotographic photoreceptor having a photosensitive layer formed by laminating a charge generation layer and a charge transfer layer on a conductive support, the residual solvent concentration in the charge transfer layer is set to 5000 pp.
Provided is an electrophotographic photoreceptor characterized in that the thickness is less than or equal to m.

A feature of the electrophotographic photoreceptor of the present invention is that the concentration of the residual coating organic solvent in the charge transfer layer is 5000 ppm or less.

The concentration of residual coating organic solvent contained in the charge transfer layer is 500%.
If it is 0 ppm or more, toner, developer, etc. tend to stick to the surface of the charge transfer layer, causing background smudges on copied images, making it impossible to achieve the object of the present invention.

In general, the coating solvent used when coating such a charge transfer layer has good compatibility with the resin binder and film-forming resin that form the photosensitive layer, so it is not included in the charge transfer layer. In order to prevent 5000 ppm or more of the coating organic solvent from remaining, it is necessary to adopt specific drying conditions.

Therefore, in the present invention, when the charge generation layer coating solution is coated on the support, and then the charge transfer layer is coated, the coating solvent is dried and removed, the drying conditions include a hot air length A time drying method is used.

In this case, the drying temperature varies depending on the type of resin used and the components of the photosensitive layer, but is usually below the Tg of the polymer, at 60°C.
-140°C, preferably 110-130°C.

The charge generation layer is formed from a charge generation substance and an organic solvent, or a resin binder and a charge generation substance.

Examples of the charge generating substance include CI Pigment Blue 25 [Color Index (CI) 211803,
CI Pigment Red 41 (CI 21200),
C.I. Acid Red 52 (CI 45100), C.I. Basic Red 3 (CI 45210), and a phthalocyanine pigment having a porphyrin skeleton,
Azulenium salt pigments, squalic salt pigments, azo pigments with a carbazole skeleton (described in JP-A No. 53-95033), azo pigments with a stilbene skeleton (described in JP-A-53-138229), triphenylamine skeletons (described in JP-A No. 53-132547), azo pigments with a dibenzothiophene skeleton (described in JP-A-54-21728), azo pigments with an oxadiazole skeleton (described in JP-A-54-1988), -1274
2), azo pigments having a fluorenone skeleton (described in JP-A No. 54-22834), azo pigments having a bisstilbene skeleton (described in JP-A-54-17733), distyryl oxadi Azo pigments having an azole skeleton (described in JP-A-54-2129), azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-2129),
4-17734), triazo pigments having a carbazole skeleton (JP-A-57-195767,
57-195768), phthalocyanine pigments such as CI Pigment Blue 16 (CI 74100), CI Bat Brown 5 (CI
73410), CI 7303
Indigo pigments such as 0).

Organic pigments such as perylene pigments such as Argo Scarlet B (manufactured by Violet Co., Ltd.) and Indus Thread Scarlet R (manufactured by Bayer Co., Ltd.) can be used.

The thickness of the charge generation layer is suitably about 2 μm, preferably 0.1 to 1 μm.

The charge generation layer can be formed by dispersing the charge generation substance described above in a suitable organic solvent, coating the dispersion, and drying the dispersion. Benzene is used as an organic solvent.

Toluene, xylene, methylene chloride, dichloroethane,
Monochlorobenzene, dichlorobenzene.

Ethyl acetate, butyl acetate, methyl ethyl ketone, dioxane, tetrahydrofuran, cyclohexanone, methyl cellosolve, ethyl cellosolve, and the like can be used alone or in combination. Also.

A resin binder described later can be used if necessary.

The charge transfer layer can be formed by dissolving a charge transfer substance and a resin binder to be described later in a suitable organic solvent, coating the solution on the charge generation layer so that the concentration of the residual organic solvent is 5000 ppm or less, and drying. Moreover, a plasticizer, a leveling agent, etc. can also be added if necessary.

Charge transfer substances include poly-N-vinylcarbazole and its derivatives, poly-rubazolylethyl glutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, and oxazole derivatives. Azole derivatives, imidazole derivatives, triphenylamine derivatives, 9-(p-diethylaminostyryl)anthracene, 1,1-bis-(4-dibenzylaminophenyl)propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α- Examples include electron-donating substances such as phenylstilbene derivatives.

As the organic solvent at this time, tetrahydrofuran, cyclohexanone, dioxane, toluene, monochlorobenzene, dichloroethane, methylene chloride, etc. can be used.

The appropriate thickness of the charge transfer layer is about 5 to 100 μm.

Examples of the resin binder used in the charge generation layer or charge transfer layer include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, styrene-methyl methacrylate copolymer, polyester, and polystyrene. Vinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride.

Polyacrylate resin, polymethacrylate resin, phenoxy resin, polycarbonate, cellulose acetate resin,
Ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyltoluene, polysulfone,
Examples include thermoplastic or thermosetting resins such as acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin.

In addition, the conductive support as used in the present invention is intended to supply charges of opposite polarity to the charged charges to the substrate side, has an electrical resistance of 10'Ω or less, and has an intermediate layer, Any material that can withstand the conditions for charge generation and charge transfer layer formation can be used. Examples of these are A(1, N
electrically conductive metals and alloys such as i, Cr, Zn, and stainless steel, inorganic insulating materials such as glass and ceramics, and polyester, polyimide, phenolic resin,
AQ is applied to the surface of organic insulating materials such as nylon resin and paper by methods such as vacuum evaporation, sputtering, and spray painting.
, Ni, Cr, Zn, stainless steel, carbon, SnO2
, those coated with an electrically conductive material such as In2O3 and subjected to conductive treatment.

Furthermore, in the present invention, between the support and the photosensitive layer,
Provide an intermediate layer of polyamide, polyvinyl alcohol, polyvinyl acetal, polyacrylic acid, polyhydroxymethacrylate, epoxy resin, etc., or a white pigment layer consisting of the above resin and a white pigment such as titanium oxide, zinc oxide, magnesium oxide, barium sulfate, lithopone. You can also do it.

〔effect〕

Since the electrophotographic photoreceptor of the present invention has the above configuration,
Since there is no surface adhesion of developer such as toner, sensitivity does not decrease even after repeated use, and increase in residual potential is suppressed, clear copied images without scumming can be obtained.

〔Example〕

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

Example 1 A cyclohexanone solution containing 1 weight 2 of the pigment represented by the following formula (1) was coated on an aluminum cylinder with a diameter of 80 mm by dip coating, and then dried at 110°C to form a charge film with a thickness of 0.14. A generation layer was formed.

Next, on the charge generation layer, a polycarbonate resin (Panlite C-1400 manufactured by Teijin Chemicals) and the following formula (II) were applied.
A tetrahydrofuran solution adjusted so that the weight ratio of the charge transfer substance shown in Table 1 is 9=10 and the solid content concentration is 18 weight deg is applied by dip coating method, and then as shown in Table 1, Photoreceptors were prepared by drying under Ht conditions to form charge transport layers with various residual solvent concentrations.

11. Transfer the electrophotographic photoreceptor obtained above to ■ Ricoh's copier FT4.
820, and after making 2000 copies, the photoreceptor was removed and its surface condition and copied images were evaluated. The results are shown in Table-1.

Note that the method for measuring the residual solvent, the evaluation method for the surface condition of the photoreceptor, and the evaluation method for the copied image were as follows.

[Method for measuring residual solvent amount]

The amount of residual solvent in the charge transfer layer was calculated from the calibration curve of the standard solution below.

1. Measurement conditions 1. The judgment was made by visually observing the 2000th copy image.

0...Clear with no background stains Δ: Clear, but background stains occur ×...Scirting is noticeable and the image is unclear Table-1 [Evaluation of surface condition of photoreceptor] On the surface of the photoreceptor after copying 2000 sheets The presence or absence of this was visually determined.

O: There are almost no stuck substances. Δ...Some adherents are present X: Significant presence of fixed substances [Evaluation of copied images] Toner stuck matter

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor comprising a photosensitive layer formed by laminating a charge generation layer and a charge transfer layer on a conductive support,
A photoreceptor for electrophotography, characterized in that the concentration of residual solvent in the charge transfer layer is 5000 ppm or less.