JPH04261546A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To ensure spectral sensitivity characteristics in the wide wavelength region from the visible to the infrared region by dispersing a mixture of, as an electric charge generating maternal, selenium or its alloy, and a specified titanyl phthalocyanine into the same binder resin. CONSTITUTION:The 2 kinds of the charge generating materials of selenium or its alloy and the titanyl phthalocyanine represented by formula I are dispersed into the same binder resin in the photosensitive layer, and the photosensitive layer of a single layer structure containing the charge generating material and a charge transfer material may be used but it is preferred to use the laminate structure formed by successively laminating the charge generating layer and the charge transfer layer.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an electrophotographic photoreceptor, and in particular to an electrophotographic photoreceptor comprising a charge generation layer and a charge transport layer sequentially laminated on a conductive support. Regarding.

Conventional technology A functionally separated type electrophotographic photoreceptor having a charge generation layer and a charge transport layer has been proposed, and in recent years, these photoreceptors have been used not only in electrophotographic copying machines but also in semiconductor lasers, light emitting diodes, etc. as light sources. There is a strong demand for charge-generating materials having a wide range of spectral sensitivity characteristics from the visible to the infrared region (400 to 800 nm) for use as photoreceptors in printers and the like.

Hitherto, various charge generation materials have been proposed. For example, in Japanese Patent Publication No. 59-32788, at least two types of pigment dyes (long wavelength and It has been proposed to use phthalocyanine on the side.

(Problems to be Solved by the Invention) However, to date, very few single charge-generating materials having the above characteristics have been found, and the An electrophotographic photoreceptor using at least two types of pigment dyes having spectral sensitivity characteristics in different spectral regions in a charge generation layer, as typified by There is a problem in that the sensitivity locally decreases significantly compared to the conventional system used alone. That is, Figures 2 and 3
The figure shows the spectral sensitivity characteristics in the example of Japanese Patent Publication No. 59-32788. In the figure, the vertical axis indicates the sensitivity 1/E1/2, and D is N,N'-dimethylperylene-3,4,9 ，
In the case of 10-tetracarboxylic acid diimide alone, E shows the spectral sensitivity curve when metal-free phthalocyanine alone, F shows the spectral sensitivity curve when both are used together (B/C = 97/3), and G shows the spectral sensitivity curve when flavanthrone pigment alone. In this case, H represents the phthalocyanine pigment alone, and I represents the spectral sensitivity of a mixture of the two. As is clear from this figure, even if two types of pigments are used together,
Sensitivity decreases significantly locally and sufficient sensitivity cannot be obtained. There is also the problem that electrophotographic properties such as chargeability and dark decay change significantly.

The present invention has been made to solve the above-mentioned problems in the conventional technology. Therefore, an object of the present invention is to provide an electrophotographic photoreceptor that has a wide range of spectral sensitivity characteristics from the visible to the infrared region and also has extremely excellent other electrophotographic characteristics.

(Means for Solving the Problems) The object of the present invention is to combine two types of selenium or selenium alloy and titanyl phthalocyanine represented by the following general formula (I) in the same bond as charge-generating materials in a photosensitive layer. This can be achieved by dispersing it in a resin.

The present invention will be explained in more detail below.

In the present invention, the photosensitive layer formed on the conductive support may have a single-layer structure containing a charge-generating material and a charge-transporting material. Preferably.

4 to 76 are schematic cross-sectional views of the electrophotographic photoreceptor of the present invention. In FIG. 4, a charge generation layer 1 and a charge transport layer 2 are sequentially provided on a conductive support 3. In FIG. 5, an undercoat layer 4 is provided between the conductive support 3 and the charge generation layer 1. In FIG. 6, a protective layer 5 is provided on the surface of the charge transport layer 3, and a seventh
In the figure, an undercoat layer 4 is provided between the conductive support 3 and the charge generation layer 1, and a protective layer 5 is provided on the surface of the charge transport layer 2.

Next, each layer constituting the electrophotographic photoreceptor of the present invention will be explained.

The conductive support in the electrophotographic photoreceptor of the present invention includes a drum made of metal such as aluminum, copper, iron, zinc, and nickel, and a drum made of metal such as aluminum, copper, gold, silver, etc. on a sheet, paper, plastic, or glass. Depositing metals such as platinum, palladium, titanium, nickel-chromium, stainless steel, copper-indium, depositing conductive metal compounds such as indium oxide, tin oxide, laminating metal foil, or carbon black. , indium oxide, tin oxide, antimony monoxide powder, metal powder, etc., are dispersed in a binder resin and applied to conductive treatment. Known materials such as drum-shaped, sheet-shaped, or plate-shaped materials can be used. It is not limited to these.

Further, if necessary, the surface of the conductive support can be subjected to various treatments as long as the image quality is not affected. For example, the surface can be subjected to oxidation treatment, chemical treatment, coloring treatment, etc.

Further, an undercoat layer may be further provided between the conductive support and the charge generation layer. This undercoat layer prevents the injection of charge into the photosensitive layer, which has a laminated structure, and also acts as an adhesive layer that holds the photosensitive layer integrally bonded to the conductive support, or in some cases acts as a conductive support. Shows effects such as preventing light reflection on the body.

Binder resins used for this undercoat layer include polyethylene, polypropylene, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate, polyurethane, polyimide resin, vinylidene chloride resin, polyvinyl acetal resin,
Known resins such as vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol, water-soluble polyester, nitrocellulose, casein, and gelatin can be used.

Further, the appropriate thickness of the undercoat layer is 0.01 to 10 μm, preferably 0.05 to 2 μm.

As a charge generating material to be included in the photosensitive layer or charge generating layer,
In the present invention, the selenium or selenium alloy and titanyl phthalocyanine are used together, and these selenium and selenium alloys include amorphous selenium, trigonal selenium, selenium-tellurium alloy, selenium-tellurium-arsenic alloy,
and mixtures thereof. In the present invention,
Among these, it is particularly preferable to use trigonal selenium.

The blending ratio (volume ratio) of selenium or selenium alloy and titanyl phthalocyanine used in the present invention is 10:1 to titanyl phthalocyanine to selenium or selenium alloy.
The range is preferably 1:1, more preferably 9:1 to 7.
:3 range.

When the electrophotographic photoreceptor of the present invention has a laminated structure, the binder resin of the charge generation layer may be a known material such as polystyrene resin, polyvinyl acetal resin, acrylic resin, methacrylic resin, polycarbonate resin, or phenol resin. Alternatively, they may be used in combination, but the invention is not limited thereto.

The blending ratio (volume ratio) of both the selenium or selenium alloy and the phthalocyanine derivative and the binder resin is 10:1 to 10:1.
A range of 1:10 is preferred.

As a method for dispersing the selenium, selenium alloy, and titanyl phthalocyanine in the binder resin, a conventional method such as a ball mill dispersion method, an attritor dispersion method, a sand mill dispersion method, etc. can be used. and titanyl phthalocyanine may be premixed and dispersed, or individually dispersed and mixed.

Furthermore, during this dispersion, the particle size is 5 μm or less, preferably 2 μm.
It is effective to make the particle size less than μm, more preferably less than 0.5 μm.

In addition, the solvents used for these dispersions include methanol,
Common organic solvents such as ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, dioxane, tetrahydrofuran, methylene chloride, and chloroform are used alone or in combination of two or more. be able to.

Further, the thickness of the charge generation layer used in the present invention is generally 0.
A suitable thickness is 1 to 5 μm, preferably 0.2 to 2 μm.

The charge transport layer in the electrophotographic photoreceptor of the present invention is formed by containing a charge transport material in a suitable binder. As charge transport materials, oxadiazole derivatives such as 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1-[pyridyl( 2)]-3-(p-
Pyrazoline derivatives such as (diethylaminophenyl) pyrazoline, aromatic tertiary amino compounds such as triphenylamine and dibenzylaniline, N,N'-diphenyl-N,N
Aromatic tertiary diamine compounds such as '-bis-(3-methylphenyl)-[1,1'biphenyl]-4,4'-diamine, 3-(4'-dimethylaminophenyl)-5,
1,2,4-triazine derivatives such as 6-di-(4'methoxyphenyl)-1,2,4-triazine, hydrazone derivatives such as 4-diethylaminobenzaldehyde-1,1'-diphenylhydrazone, 2-phenyl Quinazoline derivatives such as -4-styrylquinazoline, benzofuran derivatives such as 6-hydroxy-2,3-di(p-methoxyphenyl)benzofuran, p-(2,2-diphenylvinyl)-N,N-diphenylaniline, etc. α-Stilbene derivative of ``Journal of Imaging Science''
ence) 29:7￣10 (1985), poly-
N-vinylcarbazole and its derivatives, poly-γ-carbazole ethylglutamate and its derivatives, as well as pyrene, polyvinylpyrene, polyvinylanthracene,
Known charge transport materials such as polyvinylacridine, poly-9-biphenylanthracene, pyrene-formaldehyde resin, and ethylcarbazole-formaldehyde resin can be used, but are not limited thereto. Further, these charge transport materials can be used alone or in combination of two or more.

Furthermore, the binder resin used for the charge transport layer includes polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, Vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-
Maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin,
Known resins such as styrene-alkyd resin and poly-N-vinylcarbazole can be used, but are not limited to these.

Further, these binder resins can be used alone or in combination of two or more types.

Solvents used when forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene, ketones such as acetone and 2-butanone, and halogenated fats such as methylene chloride, chloroform, and ethylene chloride. Common organic solvents such as hydrocarbons, tetrahydrofuran, cyclic or linear ethers such as ethyl ether, etc. can be used alone or in combination of two or more.

Furthermore, a protective layer may be provided on the charge transport layer if necessary. This protective layer is used to prevent chemical deterioration of the charge transport layer when the photosensitive layer having a laminated structure is charged, and to improve the mechanical strength of the photosensitive layer.

This protective layer is formed by incorporating a conductive material in a suitable binder. Examples of conductive materials include metallocene compounds such as N,N'-dimethylferrocene, N,N'-diphenyl-N,N'-bis(3-methylphenol)-[1
, 1-biphenyl]-4,4'-diamine, and metal oxides such as antimony oxide, tin oxide, titanium oxide, indium oxide, tin oxide, and antimony monoxide. In addition, the binder resin used for this protective layer includes polyamide resin, polyurethane,
Known resins such as polyester resin, epoxy resin, polyketone resin, polycarbonate, polyvinyl ketone resin, polystyrene, and polyacrylamide resin can be used.

In addition, this protective layer has an electrical resistance of 109 to 1014 Ω.
It is preferable to configure it so that it becomes cm. electrical resistance is 1
If it exceeds 0.14 Ω·cm, the residual potential will increase, resulting in copies with a lot of fog, and if it falls below 10 9 Ω·cm, blurring of the image and reduction in resolution will occur. or,
The protective layer must be constructed so as not to substantially obstruct the passage of light used for imagewise exposure.

The appropriate thickness of the protective layer used in the present invention is 0.5 to 20 μm, preferably 1 to 10 μm.

As a coating method for forming each of the above layers constituting the electrophotographic photoreceptor, a conventional method such as a blade coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, a curtain coating method, etc. is used. be able to.

The present invention will be explained below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

(Example) A dispersion liquid (A) for forming a charge generation layer was prepared using the following components. That is, a mixture consisting of 22 g of trigonal selenium, 3 g of modified polyvinyl butyral resin, 50 g of butyl acetate, and 15 g of butanol was placed in a ball mill pot, and milled for 60 hours using 1/8 inch diameter stainless steel balls as milling members to form a charge generating layer. A dispersion liquid (A) was prepared.

Next, a dispersion liquid for forming a charge generation layer (
B) was prepared. That is, a mixture consisting of 6 g of titanyl phthalocyanine, 4 g of modified polyvinyl butyral resin, and 90 g of butanol was placed in a sand mill pot, and milled for 15 hours using glass beads with a diameter of 1 mm as a mill member to obtain a dispersion liquid (B) for forming a charge generation layer. Prepared.

Next, 100 g of the dispersion liquid (A) and 75 g of the dispersion liquid (B) obtained in this way were mixed, and 10 g of butyl acetate was added.
A coating solution for forming a charge generation layer was prepared by adding 0 g of the solution and stirring the solution.

The resulting coating solution for forming a charge generation layer was dip coated onto an aluminum substrate to form a charge generation layer having a thickness of 0.2 μm after drying.

Next, a coating solution for forming a charge transport layer having the following composition was applied by dip coating onto the charge generation layer to form a charge transport layer having a thickness of 25 μm after drying. An electrophotographic photoreceptor consisting of a transport layer was produced.

8 g Polycarbonate resin 12 g Monochlorobenzene 80 g The electrophotographic photoreceptor thus obtained was tested at room temperature (2
The following measurements were carried out in an environment of 5° C. and 40% RH. V0
: Surface potential immediately after negative charging with −6.0 kV corona discharge, V1.0: Surface potential after 1 second, DV/DE: 550 nm or 800 nm using a band pass filter.
Attenuation rate of surface potential with light spectrally separated, RP: 50erg
Surface potential after irradiation with white light of /cm2 for 0.5 seconds. The above measurement was carried out after the first cycle and after repeating the operation 1000 times continuously. The obtained characteristic values were as follows.

(1 cycle) V0: -870V Dark decay rate | V0-V1.0 |: 58V/sec DV/DE (
550nm): 248V・cm2/ergDV/DE(
800nm): 259V・cm2/ergRP: -20
V (1000 cycles) V0:-865V Dark decay rate |V0-V1.0|:60V/sec DV/DE(
550nm): 246V・cm2/ergDV/DE(
800nm): 255V・cm2/ergRP: -24
V Further similar measurements were performed at high temperature and high humidity (30°C, 80% RH).
The test was carried out under a low temperature and low humidity (10° C., 20% RH) environment, and the following characteristic values were obtained.

High temperature and high humidity (30°C, 80% RH) (1 cycle) V0: -855V Dark decay rate | V0 - V1.0 |: 61V/sec DV/DE (
550nm): 252V・cm2/ergDV/DE(
800nm), 260V cm2/ergRP: -19
V (1000 cycles) V0:-851V Dark decay rate |V0-V1.0|:63V/sec DV/DE(
550nm): 252V・cm2/ergDV/DE(
800nm): 259V・cm2/ergRP: -22
V Low temperature and low humidity (10℃, 20%RH) (1 cycle) V0: -855V Dark decay rate | V0 - V1.0 |: 54V/sec DV/DE (
550nm): 245V・cm2/ergDV/DE(
800nm): 252V・cm2/ergRP: -32
V (1000 cycles) V0:-849V Dark decay rate |V0-V1.0|:56V/sec DV/DE(
550nm): 242V・cm2/ergDV/DE(
800nm): 251V・cm2/ergRP: -35
V For the above electrophotographic photoreceptor, 400 nm to 850 nm
Figure 1 shows the spectral and sensitivity characteristics in the range of . In Figure 1, A
represents the spectral sensitivity of the electrophotographic photoreceptor, B represents the spectral sensitivity of selenium, and C represents the spectral sensitivity of titanyl phthalocyanine.

As is clear from the above results, the above-mentioned electrophotographic photoreceptor has a wide range of spectral sensitivity from visible to infrared regions, and its sensitivity is almost impaired compared to when each pigment is used alone. It can be seen that other electrophotographic properties (especially environmental/repetitive stability) are also very excellent.

Example 2 A dispersion liquid for forming a charge generation layer was prepared using the following components. That is, a mixture consisting of 5 g of trigonal selenium, 5 g of vinyl chloride-vinyl acetate maleic anhydride copolymer resin, 5 g of titanyl phthalocyanine, and 70 g of butyl acetate was placed in an attritor pot, and a stainless steel ball with a diameter of 1/8 inch was used as a mill member. 45
A dispersion liquid for forming a charge generation layer was prepared by milling for a period of time.

Next, 100% butyl acetate was added to the dispersion thus obtained.
g was added to dilute the mixture and stirred to prepare a coating solution for forming a charge generation tank.

The resulting coating solution for forming a charge generation layer was dip coated onto an aluminum substrate to form a charge generation layer having a thickness of 0.15 μm after drying.

Next, a charge transport layer having a thickness of 20 μm was formed in the same manner as in Example 1 using a charge transport layer forming liquid having the following composition.

5g Polycarbonate resin 5g Monochlorobenzene 90g Example 1 Using the electrophotographic photoreceptor thus obtained
When similar measurements were carried out, the following characteristic values were obtained.

Room temperature (25℃, 40%RH) (1 cycle) V0: -843V Dark decay rate | V0-V1.0 |: 72V/sec DV/DE (
550nm): 272V・cm2/ergDV/DE(
800nm): 263V・cm2/ergRP: -15
V (1000 cycles) V0:V Dark decay rate | V0-V1.0 |: -838V/sec DV/D
E (550nm): 270V・cm2/ergDV/D
E (800nm): 259V・cm2/ergRP:-
19V As is clear from these results, this electrophotographic photoreceptor also has a wide spectral sensitivity from the visible to the infrared region, as in Example 1, and also has very excellent other electrophotographic properties. Example 3 A drum-type photoreceptor was produced under the same conditions as Example 1, and this electrophotographic photoreceptor was used in an electrophotographic copying machine (FX-2700 modified machine manufactured by Fuji Xerox Co., Ltd., exposure wavelength: visible light region). )
When the camera was attached to the camera and a copy image was formed, a clear image with high contrast and good reproducibility was obtained. Further, when copying was repeated 10,000 times, an image equivalent to the first copy was obtained until the end. Furthermore, this electrophotographic photoreceptor was used in a semiconductor laser printer (manufactured by Fuji Xerox Co., Ltd.: FX).
When a copy image was formed using the XP-11 exposure wavelength (infrared light region), a clear printed image with high contrast and good reproducibility was obtained, as in the case described above.

(Effects of the Invention) As described above, since the electrophotographic photoreceptor of the present invention uses both selenium or a selenium alloy and titanyl phthalocyanine as charge generating materials, it has a wide range of spectral sensitivity characteristics from the visible to the infrared region. In addition, electrophotographic properties such as chargeability and dark decay are also improved.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the spectral sensitivity characteristics of the photoreceptor of Example 1 of the present invention, and FIGS. 2 and 3 are graphs showing the spectral sensitivity characteristics of the conventional electrophotographic photoreceptor, respectively.
FIGS. 4 to 7 each show a schematic cross-sectional view of the electrophotographic photoreceptor of the present invention. 1---Charge generation layer, 2---Charge transport layer, 3---
--Conductive support, 4----Undercoat layer, 5----Protective layer Applicant: Fuji Xerox Co., Ltd. Agent Patent attorney: Fujio Oda Patent attorney Akira Hayakawa

Claims (1)

[Claims] [Claim 1] An electrophotographic photoreceptor having a photosensitive layer on a conductive support, in which selenium or a selenium alloy and a titanyl phthalocyanine represented by the following general formula (I) are the same bond as charge generating materials. An electrophotographic photoreceptor characterized by being mixed and dispersed in a binder resin.