JPH01319752A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve sensitivity and productivity of a photosensitive body by incorporating a specified stilbene deriv. into a photosensitive layer and specifying an amt. of a cyclic ketonic solvent remaining in the layer. CONSTITUTION:A charge generating layer 15 contg. a charge generating material (e.g. disazo pigment) and a charge transfer layer 17 contg. an alpha-phenyl stilbene compd. expressed by a formula I are laminated successively on an electroconductive substrate 11, interposing if necessary an undercoating layer 19. At least one of the layers 15, 17 is formed by a coating stage using a cyclic ketonic solvent (e.g. cyclohexanone), and the amt. of residual cyclic ketonic solvent in the layer is regulated to 100-10,000ppm. In the formula I, R<1> is an alkyl or aryl group; each R<2> to R<4> is H, aryl, etc.; Ar<1> is aryl; Ar<2> is arylene. Compds. expressed by the formula II may be useful as the compds. of the formula I.

Description

[Detailed Description of the Invention] [Prior Art] Electrophotographic photoreceptors have been known in which a photosensitive layer containing an organic conductive substance such as an azo pigment as an active ingredient is provided on a conductive support. There is. These organic electrophotographic photoreceptors have various excellent physical properties, but one of their major features is that a photosensitive layer can be formed by a coating process. These organic electrophotographic photoreceptors can take various forms, but are typically of a functionally separated type in which the photosensitive layer is composed of a stacked M structure of a charge generation layer and a charge transfer layer. This photoreceptor is usually manufactured as follows. first,
A charge generation layer coating solution is purified by dispersing or dissolving a charge generation substance and, if necessary, a resin binder in a solvent, and this is coated on a conductive support directly or via a subbing layer,
Dry to form a charge generation layer. Next, the charge transfer substance and the resin binder are dissolved or dispersed in a solvent, coated on the charge generation layer, and dried to form a charge transfer layer. When a photosensitive layer is formed through such a coating process, there is a wide range of support materials to choose from, and the productivity is extremely good, which is said to be industrially advantageous.

Tetrahydrofuran and the like have been used as this solvent, but there have been problems in terms of sensitivity and productivity. In order to solve this problem, a specific triazo pigment is used as a charge generating substance, and the amount of residual halogenated solvent in the photosensitive layer is reduced to 500%.
Although an electrophotographic photoreceptor having a weight of ρpm or less has been proposed (Japanese Unexamined Patent Publication No. 62-287256), it does not necessarily satisfy the above requirements.

[Problem that the invention seeks to solve]

An object of the present invention is to provide an electrophotographic photoreceptor that has excellent sensitivity and high productivity.

[Means to solve the problem]

According to the studies of the present inventors, the above purpose was achieved by using a compound represented by the following general formula (1) as a charge transfer substance, and reducing the concentration of the residual cyclic ketone solvent in the photosensitive layer from 100 to io, ooo.
It has been found that this can be achieved by adjusting the amount to ppm by weight.

That is, the electrophotographic photoreceptor of the present invention has a photosensitive layer formed through a coating process using a cyclic ketone solvent, and the photosensitive layer contains α-phenyl represented by the following general formula (1). Contains at least one stilbene compound as an active ingredient, and the residual cyclic ketone solvent in the photosensitive layer is 100 to 100%.
The content is 10,000 ppm by weight.

(In the formula, R1 is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, and R2, R3, and R4 are hydrogen atoms, substituted or unsubstituted alkyl groups, substituted or unsubstituted aralkyl groups, represents a substituted aryl group or a substituted or unsubstituted aralkyl group, Ar1 represents a substituted or unsubstituted aryl group, and Ar1 represents a substituted or unsubstituted aryl group;
2 represents a substituted or unsubstituted arylene group. Ar1 and R1 may jointly form a ring. n is an integer of 0 or 1. ) Hereinafter, the present invention will be explained in more detail with reference to the accompanying drawings.

FIG. 1 is a sectional view illustrating the layer structure of the electrophotographic photoreceptor of the present invention. A charge generation layer 1 is provided on the conductive support 11.
5 and the charge transfer layer 17 are sequentially laminated to form the photosensitive layer 13.
It consists of Charge generation/[15] is formed by uniformly dispersing a charge generation substance.

FIG. 2 is a sectional view showing another example of the structure of the electrophotographic photoreceptor of the present invention, except that an undercoat layer 19 is provided between the conductive support 11 and the charge generation layer 15.

It is similar to that in FIG.

In the present invention, at least one of the photosensitive layer 13, that is, the charge generation layer 15 and the charge transfer layer 17, is formed through a coating process using a cyclic ketone solvent. Examples of cyclic ketone solvents include cyclohexanone, methylcyclohexanone,
Examples include cyclopentanone.

Additionally, solvents other than cyclic ketone-based solvents may be combined with other solvents, such as:
Examples include benzene, toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, dioxane, tetrahydrofuran, methyl cellosolve, and ethyl cellosolve.

Note that either the charge generation layer or the charge transport layer may be formed without using a cyclic ketone solvent.

For the charge generation layer, a charge generation layer coating solution is prepared by dispersing or dissolving a charge generation substance and, if necessary, a resin binder in a solvent, and this is supported using a dip coating solution, a doctor blade, a wire blade, an air knife, etc. It can be formed by applying it on the body and drying it. When a cyclic ketone solvent is used as the solvent, the amount of residual cyclic ketone solvent in the charge generation layer can be controlled by adjusting the heating temperature and heating time during drying.

The charge transfer layer is prepared by dissolving or dispersing the charge transfer substance of the general formula (1) and the binder resin in a solvent to prepare a charge transfer layer coating solution, which is coated on the charge generation layer in the same manner as above and dried. It can be formed by When a cyclic ketone solvent is used as the solvent, the amount of the cyclic ketone solvent in the charge transfer layer can be controlled by adjusting the heating temperature and heating time during drying.

In the present invention, the residual cyclic ketone solvent in the entire photosensitive layer is set to too-io, ooo ppm by weight, and the α-phenylstilbene compound represented by the general formula (I) is used as the charge transfer substance, thereby making it possible to take electrophotographic images. The sensitivity of the photoreceptor and its productivity can be improved.

If the concentration of the residual cyclic ketone solvent is less than 100 ppm by weight or exceeds 10,000 ppm by weight, it is undesirable because the photosensitivity decreases.

As the charge generating substance, for example, C.I. Pigment Blue 25 [Color Index (CI) 211803]
, CI Pigment Red 41 (CI 21200)
, Sea Eye Acid Red 52 (CI 45100),
CI Basic Red 3 (CI 45210), a phthalocyanine pigment with a porphyrin skeleton, an azo pigment with a carbazole skeleton (JP-A-53-9
5033), azo pigments having a distyrylbenzene skeleton (described in JP-A-53-133455), azo pigments having a triphenylamine skeleton (described in JP-A-53-132547), dibenzo Azo pigments having a thiophene skeleton (described in JP-A-54-21728), azo pigments having an oxadiazole skeleton (
(described in JP-A-54-12742), azo pigments having a fluorenone skeleton (described in JP-A-54-22834), azo pigments having a bisstyrylbene skeleton (described in JP-A-54-17733) ), an azo pigment having a distyryl oxadiazole skeleton (JP-A-54-21
29), an azo pigment having a distyrylcarbazole skeleton (described in JP-A-54-17734)
, furthermore, CI Pigment Blue 16 (CI 74
100), C.I. Butt Brown 5 (CI73410), C.I. Butt Dye (
Examples include indigo pigments such as CI 73030), perylene pigments such as Argo Scarlet 8 (manufactured by Violet), and Indanthrene Scarlet R (manufactured by Bayer). These charge generating substances may be used alone or in combination of two or more.

Any resin binder can be used as long as it has film-forming properties and insulation properties, such as polyamide, polyurethane, polyester resin, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, and polyvinyl. Examples include formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide.

The resin binder is suitably used in an amount of 0 to 100 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the charge generating material.

The thickness of the charge generation layer 15 is suitably about 0.05 to 1 tone, preferably 0.1 to 0.5 μs.

The charge transfer layer 17 contains a charge transfer substance and a resin binder, and may also contain a plasticizer, a leveling agent, etc., if necessary.

As the charge transfer substance, one represented by the following general formula (1) is used.

(In the formula, R1 is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, and R2, R3, and R4 are hydrogen atoms, substituted or unsubstituted alkyl groups, substituted or unsubstituted aralkyl groups, represents a substituted aryl group or a substituted or unsubstituted aralkyl group, Ar1 represents a substituted or unsubstituted aryl group, Ar
"represents a substituted or unsubstituted arylene group. Ar1 and R
1 may jointly form a ring. n is an integer of O or 1. ) As a binder, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polychloride Vinylidene, polyarylate resin,
Phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyltoluene, poly-N-
Vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin.

Examples include thermoplastic or thermosetting resins such as phenolic resins and alkyred resins.

The appropriate thickness of the charge transfer layer 17 is about 5 to 100 mm.

The conductive support 11 may be a plastic film on which aluminum, nickel, chromium, nichrome, copper, tin oxide, indium oxide, etc. is vapor-deposited, a plate made of aluminum, nickel, stainless steel, etc.
, 1. It is possible to use pipes that have been made into blank pipes by methods such as , extrusion, and drawing, and then surface-treated by cutting, superfinishing, polishing, and the like.

The undercoat layer 19 improves chargeability, adhesion, and surface properties of the substrate.
It is used to prevent moiré by dispersing a pigment having a higher refractive index than the resin forming the subbing layer, such as O1ZnS. As this resin, copolyamide, alcohol-soluble nylon, polyvinyl butyral (JP-A-60-362553, JP-A-60-232554), etc. can be used.

The thickness of the subbing layer I7 is suitably about 0.01 to 10 Jm, preferably 0.01 to 51 Jm.

〔Example〕

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

Example 1 Aluminum drum (φ120mm x 340mm)
The following undercoat layer coating solution was applied by dip coating, and the coating solution was applied at 100°C for 10
After drying for a minute, a subbing layer having a thickness of 0.31 Im was provided.

[Undercoat layer coating liquid]

Nylon resin (CM-8000 manufactured by Toshisha Co., Ltd.) 8 parts by weight methanol 60 parts by weight butanol 32 parts by weight, the following charge generation layer coating solution was dip coated on this undercoat, and heated at 120°C for 10 minutes. After drying for a minute, a charge generation layer having a thickness of 0.0511 m was provided.

[Charge generation layer coating liquid]

1 part by weight of the following disazo pigment and 99 parts by weight of cyclohexanone were then applied with a spray gun (
YT-06 (manufactured by Olympus ■) was spray coated and dried at 125° C. for 10 minutes to provide a charge transfer layer with a thickness of 22 μm, thereby producing an electrophotographic photoreceptor of the present invention.

[Charge transfer layer coating liquid]

2.6-tart-butyl-P-cresol 1.
8 parts by weight Cyclohexanone 1400 parts by weight Tetrahydrofuran 1400 parts by weight Example 2 In Example 1, the drying time of the charge transfer layer was 125°C,
An electrophotographic photoreceptor of the present invention was produced in the same manner as in Example 1 except that the heating time was 20 minutes.

Example 3 In Example 1, the drying conditions for the charge transfer layer were 125°C;
An electrophotographic photoreceptor of the present invention was produced in the same manner as in Example 1 except that the heating time was 30 minutes.

Comparative Example 1 In Example 1, the drying conditions for the charge transfer layer were 125°C;
A comparative electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the heating time was 5 minutes.

Comparative Example 2 In Example 1, the drying conditions for the charge transfer layer were 125°C;
A comparative electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the heating time was 60 minutes.

Comparative Example 3 A comparative electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that cyclohexanone, the solvent for the charge transfer layer, was replaced with monochlorobenzene.

Comparative Example 4 In Example 1, 1400 parts by weight of cyclohexanone and 1400 parts by weight of tetrahydrofuran, which are solvents for the charge transfer layer, were added.
A comparative electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the weight part was changed to 2,800 parts by weight of tetrahydrofuran.

The electrophotographic photoreceptor produced as described above was tested at 1100 Or
After being rotated at P and charged to -800V, it was exposed to white light of 301 μs, and the exposure amount El/10 (lux-sec) at which the potential attenuated to -80V was determined and was defined as the sensitivity. The results are shown in Table-1. In addition, Table 2 shows the results of visual inspection of the state of the coating film after coating.

Table-1 Table-2

[Brief explanation of the drawing]

1 and 2 are schematic cross-sectional views of the electrophotographic photoreceptor of the present invention. 11... Conductive support 13... Photosensitive layer 1
5... Charge generation layer 17... Charge transfer layer 19... Undercoat layer

Claims (1)

[Claims] (1) It has a photosensitive layer formed through a coating process using a cyclic ketone solvent, and the photosensitive layer has the following general formula (I
1. An electrophotographic photoreceptor comprising at least one α-phenylstilbene compound represented by the following formula as an active ingredient, and wherein the residual cyclic ketone solvent in the photosensitive layer is 100 to 10,000 ppm by weight. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R^1 is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, R^2, R ^3 and R^4 represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group, Ar^1 represents a substituted or unsubstituted aryl group, Ar ^2 represents a substituted or unsubstituted arylene group. Ar^1 and R^1 may jointly form a ring. n is an integer of 0 or 1.)