JPH0378759A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity in the wide wavelength region covering from the visible wavelength region to a near infrared region by incorporating a specified squarium pigment and phthalocyanine in an electric charge generating layer. CONSTITUTION:The charge generating layer 2 is formed on a conductive substrate 1 and a charge transfer layer 3 is formed on this layer 2 to form a photosensitive layer 4. The charge generating layer 2 contains phthalocyanine represented by formula II and the squarium pigment represented by formula I in which each ef R1 and R2 is a 1- 10 C straight chain or branched alkyl group. The charge generating layer 2 is formed on the conductive substrate 1 by using only the squarium pigment and the phthalocyanine or a mixture of both and a binder resin, for example, in the case of using no binder resin, by scattering both with a solvent or vacuum evaporating both to deposit the charge generating layer on the conductive substrate, thus permitting sensitivity in the wide wavelength region from the visible wavelength region to the near infrared region to be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor used in an electrophotographic process. More specifically, the present invention relates to an electrophotographic photoreceptor containing a squareium pigment and a phthalocyanine in a charge generation layer.

[Conventional technology]

Conventionally, electrophotographic photoreceptor materials include inorganic electrophotographic photoreceptor materials such as amorphous selenium, cadmium sulfide, and zinc oxide, as well as organic electrophotographic photoreceptors typified by azo compounds and monomeric squareium pigments. The material is widely known.

[Problem to be solved by the invention]

It is well known that amorphous selenium and the like have excellent properties and have been put to practical use as electrophotographic photoreceptor materials. However, their manufacture requires a process such as vapor deposition, and the manufactured electrophotographic photoreceptor has a drawback that it is difficult to dispose of because it is toxic. Furthermore, electrophotographic photoreceptors in which zinc oxide is dispersed in a resin have poor mechanical strength and cannot withstand repeated use.

Although organic electrophotographic photoreceptor materials are excellent in processability such as film formation, they have the drawback that sufficient sensitivity cannot be obtained as an electrophotographic photoreceptor.

The purpose of the present invention is to solve the toxicity problems of existing electrophotographic photoreceptors, and to have sufficient sensitivity in a wide wavelength range from the visible region to the near-infrared region, which can be used in all currently used electrophotographic processes. An object of the present invention is to provide a photoreceptor for electrophotography.

[Means to solve the problem]

The electrophotographic photoreceptor of the present invention contains a squareium pigment represented by the general formula (I) and a phthalocyanine represented by the general formula (II) in the charge generation layer.

(However, in general formula (I), R and R2 have a carbon number of 1 to 10
represents a chain or branched alkyl group. ) The squareium pigment used in the present invention is 3,4-dihydroxy-3-cyclobutene-
1,2-dione and 10 chain or branched alkyl groups represented by the general formula (IV)2. ) can be obtained by reacting the aniline derivative shown in a solvent in a solvent. Examples of solvents include aliphatic alcohols such as methanol, ethanol, glopanol, phthanol, and amyl alcohol.

The squareium pigment represented by the general formula (I) and the phthalocyanine represented by the general formula (n) can be used as a charge generating substance for an electrophotographic photoreceptor.

Its configuration is shown in FIGS. 1 and 2.

FIG. 1 shows a charge generation layer 2 formed on a conductive support 1,
2 is a cross-sectional view of a laminated electrophotographic photoreceptor in which a charge transport layer 6 is formed on a charge generation layer 2 and a photosensitive layer 4 is formed. FIG. Second
The figure is a cross-sectional view of a laminated electrophotographic photoreceptor in which a charge transport layer 6 is formed on a conductive support 1, a charge generation layer 2 is formed on the charge transport layer 3, and a photosensitive layer 4 is formed. be. When forming the charge generation layer 2, only the squareium pigment and phthalocyanine are used on the conductive support 1 or the charge transport layer 6, or R and R2 in pine (general formula GV) are added to these. A mixture of carbon number 1 (4) resin can be used. The ratio of Nokuinda resin to Squarium pigment and phthalocyanine is from 10 to 90% by weight, preferably from 25 to 30%.
Weight%. /(When inder resin is not used, the charge generation layer 2 is formed on the conductive support 1 by spraying the squareium pigment and phthalocyanine with a solvent or by vacuum evaporation. The thickness of the charge generation layer 2 is 0. 1 to 1.0 μm, preferably 0.3 to 1.0 μm.When dispersing in the binder resin, the squareium pigment and phthalocyanine are sufficiently ground by a known method using a ball mill or paint conditioner. The binder resin used in the charge generation layer 2 may or may not have photoconductivity.For example, polyvinylcarbazole, polyvinylpyrenexole derivatives, polyvinylnaphthalene, polyvinylanthracene, polyvinylpyrene, etc. Examples include photoconductive polymers and other organic polymers with charge transport ability, IJ lux materials, etc. Known insulating resins that do not have photoconductivity can also be used. For example, polystyrene, polyester, polycarbonate, and derivatives thereof can be used. At this time, in order to increase the strength of the electrophotographic photoreceptor, a plasticizer can be used in the same manner as in general polymeric materials. As the plasticizer, chlorinated halaffin, chlorinated biphenyl, phosphate plasticizer, etc. can be used. The plasticizer is used in an amount of 20% by weight or less based on the binder resin, as long as it does not impair the properties of the electrophotographic photoreceptor. The charge generation layer 2 can be formed by applying a binder resin in which a squareium pigment and a phthalocyanine are dispersed using a known method such as a spray method or a barcoder method.

As the material of the conductive support 1, for example, aluminum, nickel, zinc, platinum, gold, stainless steel, brass, iron, palladium, or the like can be used.

Examples of the charge transport material used in the charge transport layer B include carbazole derivatives, pyrazoline derivatives, triphenylamine, hydrazone derivatives, polyvinylpyrene, polyvinylanthracene, polyvinylaziridine, and the like.

These charge transport materials can be used alone or in combination of two or more. As the binder resin used in charge transport layer B, polymers such as acrylic resin, polystyrene, polyester, polyarylate, polysulfone, and polycarbonate can be used.

The charge transport layer 6 is a charge generating layer 2 or a conductive support 1.
and the ratio of charge transport material to binder resin is less than or equal to 150% by weight.

〔Example〕

The present invention will be explained below based on Examples.

(Example 1) 20 m of a 5% by weight solution of polyester resin in cyclohexanone was added to a mixture of the following squareium pigment (0.48 mmo6) and the following phthalocyanine (0.48 mmo6).
In addition, the use and sensitivity of the paint conditioner were determined. The results are shown in Table 1.

The mixture is ground and dispersed for 1 hour, and a charge generation layer is formed on an aluminum substrate with a thickness of 0.3 to 1.0 μm using an applicator.

Next, 100% by weight of paradiethylaminobenzaldehyde diphenylhydrazone added to polycarbonate resin was applied onto the charge generation layer to form a charge transport layer with a thickness of 20 μm.
A photoreceptor for electrophotography was prepared by forming the photoreceptor.

Next, a corona discharge of -7 kV was applied to this electrophotographic photoreceptor for 2 seconds using a benograph analyzer, and then it was left in a dark place for 2 seconds, the surface potential Vo at that time was measured, and the illumination intensity was 1 μJ/cra. light from 850nm to 75Qnm
The photosensitive layer is irradiated every 5 Qnm until the surface potential becomes ■.

Measure the time (seconds) until it becomes 1/2 of the sensitivity, and the half-decrease light amount E1/2 (Example 2) An electrophotographic photoreceptor was produced in the same manner as in Example 1.

Next, a -7 kV corona discharge was applied to this electrophotographic photoreceptor using a paper analyzer for 2 seconds, and then it was left in a dark place for 2 seconds, and the surface potential ■o at that time was measured. of light from 850 nm to 75
The photosensitive layer is irradiated every 5Qnm up to Qnm, and its surface potential is ■. The time (seconds) until it becomes 1/2 of that was measured to determine the half-reduced light amount E1/2 and the sensitivity. The results are shown in Table 2.

Table 2 Table (Example 3) An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that 0.48 mm square of squareium pigment and 0.24 mm square of phthalocyanine were used.

Next, a corona discharge of -7 kV was applied to this electrophotographic photoreceptor for 2 seconds using a paper analyzer, and then it was left in a dark place for 2 seconds, the surface potential ■o at that time was measured, and then the illuminance of lμJ/cyi was measured. Light from 85Qnm to 75Qn
The photosensitive layer is irradiated every 5Qnm up to m, and the surface potential is V
The time (seconds) until o reached 172 was measured to determine the half-decrease photosensitivity E1/2 and the sensitivity. The results are shown in Table 3.

(Example 4) An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that 0.48 mm06 of the squareium pigment and 0.12 mmo13 of phthalocyanine were used.

Next, this electrophotographic photoreceptor was subjected to -7 kV corona discharge for 2 seconds using a paper analyzer, then left in a dark place for 2 seconds, the surface potential ○ at that time was measured, and then the illumination intensity was 1 μJ/c++t. Light from 35Qnm to 75Qnm
The photosensitive layer is irradiated every 5 Qnm until the surface potential becomes ■.

The time (seconds) until it becomes 1/2 of that was measured to determine the half-reduced light amount E1/2 and the sensitivity. The results are shown in Table 4.

Table 4 (Comparative Example 1) An electrophotographic photoreceptor was prepared using the following squareium pigment (0.48 mmol).

Next, this electrophotographic photoreceptor was subjected to corona discharge of -7 kV for 2 seconds using a paper analyzer, then left in a dark place for 2 seconds, the surface potential ■o at that time was measured, and then the illumination intensity was 1 μJ/cnl. Light from 35Qnm to 75Qn
The photosensitive layer is irradiated every 5 Qnm up to m, and its surface potential becomes ■
. The time (seconds) until it becomes 1/2 of that was measured to determine the half-reduced light amount E1/2 and the sensitivity. The results are shown in Table 5.

20% by weight of cyclohexanone solution of polyester resin
ml and crushed and dispersed for 1 hour using a paint conditioner to form a film with a thickness of 0.3 to 1 ml on an aluminum substrate.
．． A charge generation layer is formed using an applicator at 0 μm. On top of this, add 100% by weight of para-diethylaminobenzaldehyde diphenylhydrazone to polycarbonate resin.
The addition of phthalocyanine to an electrophotographic photoreceptor that uses squareium pigment alone as a charge generating substance significantly increases the sensitivity. improved. This solves the conventional problem of insufficient sensitivity and makes it possible to obtain a highly sensitive electrophotographic photoreceptor. In particular, the electrophotographic photoreceptor of the present invention can be used in semiconductor laser applied products because it exhibits high sensitivity in the semiconductor laser oscillation wavelength range.

Furthermore, the present invention has made it possible to provide a non-toxic electrophotographic photoreceptor.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views of an electrophotographic photoreceptor. DESCRIPTION OF SYMBOLS 1... Conductive support, 2... Charge generation layer, 6... Charge transport layer, 4... Photosensitive layer.

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor comprising a squarium pigment represented by the general formula (I) and a phthalocyanine represented by the general formula (II) in a charge generation layer. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (However, in the general formula (I), R_1 and R_2 have 1 carbon number.
represents 10 chain or branched alkyl groups. )