JP3137461B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positively charged electrophotographic photosensitive member containing, as a charge-generating substance, an .alpha.-type copper phthalocyanine composition comprising tetranitro copper phthalocyanine having a specific structure and copper phthalocyanine.

[0002]

2. Description of the Related Art At present, as a photoreceptor for electrophotography, a function-separated type photoreceptor containing a charge generating substance having photosensitivity at the wavelength of a light source and a charge transporting substance having a high charge transfer speed is widely used.

Hitherto, as a charge transporting substance, a hydrazone derivative, a styryl derivative, a pyrazoline derivative, a triphenylamine derivative, a quinone derivative, a thioxanthone derivative, etc., which are low-molecular conductive materials, have been used. Also,
As the charge generating substance, azo pigments, perylene pigments, phthalocyanine pigments and the like are used.

[0004]

The function-separated type photoreceptor is generally used as a negatively charged type photoreceptor. Therefore, there has been a problem that the surface of the photoreceptor is deteriorated due to the generation of ozone, or the charging performance is not stable.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a positively chargeable function-separated type electrophotographic photosensitive member having high photosensitivity and excellent mechanical and chemical durability.

[0006]

The electrophotographic photoreceptor of the present invention comprises a conductive support, on which a charge generation layer and a charge transport layer are sequentially laminated. The phthalocyanine (A) and copper phthalocyanine are simultaneously treated to change the crystal form to α-form, and the ratio of tetranitro copper phthalocyanine (A) is 2% by weight or more and 20% by weight.
The following α-type copper phthalocyanine composition is used for the charge generation layer.
It is characterized by containing .

[0007]

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(Where the nitro group is at the 1-position or 4-position
Position, position 8 or position 11, position 15 or position 18, and position 22 or position 25, respectively. )

Further, the electrophotographic photoreceptor of the present invention comprises a charge generation layer and a charge transport layer sequentially laminated on a conductive support, and comprises tetranitro copper phthalocyanine (B) And copper phthalocyanine at the same time to change the crystal form to α-form , and tetranitro copper phthalocyanine
The proportion of nin (B) is 1% by weight or more and 10% by weight or less
The α type copper phthalocyanine composition is characterized in the this <br/> that contained in the charge generation layer.

[0010]

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(Wherein the nitro group is at the 2-position or 3-position
Position, 9 or 10 position, 16 or 17 position, and 23 or 24 position, respectively. )

Furthermore, the electrophotographic photoreceptor of the present invention comprises a charge generation layer and a charge transport layer sequentially laminated on a conductive support, and comprises tetranitro copper phthalocyanine (A),
Tetranitro copper phthalocyanine (B) and copper phthalocyanine are simultaneously treated to change the crystal form to α-form ,
One tetranitro ratio of copper phthalocyanine (A) is 15 wt% or less, tetranitro copper phthalocyanine (B)
The proportion is not more than 8 wt%, Te Toranitoro copper phthalocyanine (A) and tetranitro copper phthalocyanine (B) and <br/> sum α type copper phthalocyanine composition is 20 wt% or less of
A charge generation layer .

[0013] The α-type copper phthalocyanine composition used in the present invention includes copper phthalocyanine and tetranitro copper phthalocyanine (A) , copper phthalocyanine and tetranitro copper phthalocyanine (B), or copper phthalocyanine and tetramethyl phthalocyanine.
Lanitro copper phthalocyanine (A) and tetranitro copper lid
It is preferable that the cysteine (B) is simultaneously treated by the acid paste method to change the crystal form to α-form.

The copper phthalocyanine and tetranitro copper phthalocyanine (A) and (B) used in the present invention can be obtained by a usual copper phthalocyanine synthesis method.

In the electrophotographic photoreceptor of the present invention, the light sensitivity can be changed by changing the ratio of tetranitro copper phthalocyanine (A) and / or tetranitro copper phthalocyanine (B) to the α-type copper phthalocyanine composition. It is. When the content of the tetranitro copper phthalocyanine (A) and / or the tetranitro copper phthalocyanine (B) relative to the α-type copper phthalocyanine composition is less than the above range, the photosensitivity as a photoreceptor decreases, When the amount is large, the charging ability is extremely reduced, and in either case, it is not suitable for practical use.

The method for producing the α-type copper phthalocyanine composition used in the present invention includes an acid paste method, an acid slurry method, a low-temperature sublimation method, and the like. In the present invention, in the obtained α-type copper phthalocyanine composition, it is important that tetranitro copper phthalocyanine is uniformly distributed in the crystals of the α-type copper phthalocyanine, and in this regard, the acid paste method is the most preferable method. It is. However, only by simply mixing the α-type copper phthalocyanine tetranitro copper phthalocyanine it can not be obtained photoreceptor characteristics of interest.

The electrophotographic photoconductor of the present invention is a function-separated electrophotographic photoconductor using an α-type copper phthalocyanine composition as a charge generating substance. The charge generation layer is prepared by dispersing an α-type copper phthalocyanine composition in a binder resin and applying this solution on a conductive support , or
Depositing copper phthalocyanine composition directly on conductive support
It is produced by the following.

As the binder resin, in addition to thermoplastic resins such as polyester resin, polycarbonate resin, polyvinyl butyral resin, etc., there is a specific volume of thermosetting resin such as polyurethane resin, epoxy resin, melamine resin, formalin resin, phenol resin and the like. A resin having high resistance can also be used.

FIG. 1 shows an example of the electrophotographic photosensitive member of the present invention. FIG. 1 is a cross-sectional view of the electrophotographic photoconductor of the present invention. In the electrophotographic photoreceptor, a charge generation layer 3 containing an α-type copper phthalocyanine composition 2 as a charge generation substance is formed on a conductive support 1, and a charge transport layer 4 containing a charge transport substance 4 thereon. The layer 5 is laminated.

The charge transporting layer 5 can be formed by dispersing the charge transporting substance 4 in a binder resin and applying this solution on the charge generating layer 3. The charge transport material 4 used for the charge transport layer 5 can be used as long as it has an electron transport ability. For example, various quinone derivatives and thioxanthone derivatives can be used. The binder resin for dispersing the charge transporting substance 4 can be used as long as it is a resin having an excellent electron transporting property, such as a polycarbonate resin or a polyester resin, having excellent adhesiveness and insulating properties.

The charge generation layer 3 or the charge-transporting layer 5, a plasticizer for a range that does not impair the feeling <br/> light body characteristics flexibility, adhesiveness, to improve the mechanical strength or chemical strength, An antioxidant for improvement may be used. Further, if necessary, an intermediate layer may be provided for the purpose of improving adhesion or preventing electron injection, or a surface protective layer may be provided for improving mechanical strength.

The coating of the charge generating layer 3, the charge transporting layer 5, the intermediate layer and the surface protective layer is usually performed using a doctor blade, a wire bar, a roll coater or the like. In the case of the electrophotographic photoreceptor of the present invention, the thickness of the charge generation layer 3 is 5 μm or less,
The thickness is preferably 0.1 to 1 μm, and the thickness of the charge transport layer 5 is 5 to 50 μm, preferably 10 to 20 μm. Further, when an intermediate layer and a surface protective layer are provided, the thickness is preferably 1 μm or less.

As the conductive support 1, those conventionally used can be used. Specifically, aluminum,
Examples thereof include a metal support such as stainless steel, copper, and brass, and an insulating support on which aluminum, indium oxide, or the like is deposited.

[0024]

The electrophotographic photosensitive member of the present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the examples.

(Example 1) 9.2 g of copper phthalocyanine and tetranitro copper phthalocyanine
Dissolve 0.8 g (8% by weight) of nin (A) in 100 g of sulfuric acid
The solution was poured into 2 L of ice water and α-type copper phthalocyanine was added.
A nin composition was obtained. This α-type copper phthalocyanine composition 5
g and 20 g of a polyester resin in cyclohexanone 180.
g, and this mixed solution was dispersed by a shaking disperser for 3 hours. The obtained solution was applied on an Al-deposited polyester film with a wire bar, and a charge generation layer having a thickness of 0.5 μm after drying was formed. Next, polycarbonate resin 1
In a mixed solution of 0 g dissolved in 90 g of cyclohexanone,
10 g of a thioxanthone derivative represented by Chemical Formula 5 was dissolved as a charge transport material. The obtained solution was applied on the charge generation layer with a wire bar to form a charge transport layer having a thickness of 20 μm, thereby producing an electrophotographic photoreceptor.

[0026] The thus electrophotographic photosensitive member produced in, and corona charging first with at + 6KV dark, were examined photoreceptor characteristics exposed 20 seconds W lamp illumination 5lux the next. The photoreceptor characteristics, after charging the initial charge potential V0,
The time tD required for the surface potential to darkly decay from 620 V to 600 V, the exposure amount E1 / 2 required for light attenuating from 600 V to 300 V, and the residual potential Vr after 20 seconds of light irradiation were measured. Further, the same operation was repeated for the electrophotographic photoreceptor, and V0 (100
0), tD (1000), E1 / 2 (1000), V
r (1000) was measured and the durability was examined repeatedly.
The results were as follows .

[0027]

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V ₀ = 760 V t _D = 14 seconds E _1/2 = 2.5 lux · second V _r = 30 V V ₀ (1000) = 750 V t _D (1000) = 12 seconds E _1/2 (1000) = 2 .3lux · sec V _r (1000) = 35V

Example 2 α containing 2% by weight of tetranitro copper phthalocyanine (B)
An electrophotographic photoreceptor was produced under the same conditions as in Example 1 except that the copper phthalocyanine composition was used . Photoreceptor characteristics were as follows.

V ₀ = 755 V t _D = 15 sec E _1/2 = 2.1 lux · sec V _r = 32 V V ₀ (1000) = 740 V t _D (1000) = 10 sec E _1/2 (1000) = 2 .1lux · sec V _r (1000) = 38V

[0031] (Example 3) tetranitro copper phthalocyanine (A) 4 wt%, and tetranitro copper phthalocyanine (B) except that had use of α type copper phthalocyanine composition containing 1% by weight, electrons under the same conditions as in Example 1 A photoreceptor was prepared. Photoreceptor characteristics were as follows.

V ₀ = 780 V t _D = 10 seconds E _1/2 = 2.7 lux · second V _r = 45 V V ₀ (1000) = 730 V t _D (1000) = 13 seconds E _1/2 (1000) = 2 .4lux · sec V _r (1000) = 31V

Comparative Example 1 An electrophotographic photoreceptor was manufactured under the same conditions as in Example 1 except that only the α-type copper phthalocyanine obtained by the acid paste method was used as the photoconductive substance. Photoreceptor characteristics were as follows.

V ₀ = 755 V t _D = 13 seconds E _1/2 = 38 lux · second V _r = 256 V V ₀ (1000) = 460 V V _r (1000) = 165 V

As described above, the initial photosensitivity was extremely reduced, and the charging performance was reduced due to repeated use, so that it could not withstand practical use.

[0036] (Comparative Example 2) to the normal α-type copper phthalonitrile <br/> cyanine obtained by acid paste method, which tetranitro copper phthalocyanine (B) was mixed so that the added amount as in Example 2 A photoreceptor for electrophotography was produced under the same conditions as in Example 1 except for using. Photoreceptor characteristics were as follows.

V ₀ = 236 V V _r = 113 V

As described above, the initial charging performance was poor and the photosensitivity was almost nil, making it unsuitable for practical use.

Example 4 An electrophotographic photosensitive member was produced under the same conditions as in Example 1 except that a thermosetting melamine resin was used as a binder resin. Photoreceptor characteristics were as follows.

V ₀ = 780 V t _D = 17 seconds E _1/2 = 2.3 lux · second V _r = 29 V V ₀ (1000) = 768 V t _D (1000) = 15 seconds E _1/2 (1000) = 2 .1lux · sec V _r (1000) = 48V

Example 5 An electrophotographic photosensitive member was manufactured under the same conditions as in Example 2 except that a thermosetting melamine resin was used as a binder resin. Photoreceptor characteristics were as follows.

V ₀ = 776 V t _D = 15 sec E _1/2 = 2.1 lux · sec V _r = 32 V V ₀ (1000) = 786 V t _D (1000) = 17 sec E _1/2 (1000) = 2 .3lux · sec V _r (1000) = 46V

[0043]

The α-type copper phthalocyanine composition used in the present invention has high sensitivity and is chemically stable, and thus has excellent repetition characteristics. Further, since the electrophotographic photoreceptor of the present invention is a positively charged type, it generates a very small amount of ozone during charging, is highly sensitive, and has high printing durability with excellent mechanical and chemical durability. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an electrophotographic photoreceptor of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive support 2 α-type copper phthalocyanine composition 3 charge generation layer 4 charge transport material 5 charge transport layer

Claims (4)

(57) [Claims] 1. An electrophotographic photoreceptor having a charge generation layer and a charge transport layer sequentially laminated on a conductive support, wherein tetranitrocopper phthalocyanine (A) and copper phthalocyanine represented by the formula 1 are simultaneously treated. To change the crystal form to α-form , and the cleavage of the tetranitro copper phthalocyanine (A)
Α-type copper phthalocyanine having a content of 2% by weight or more and 20% by weight or less
An electrophotographic photoreceptor comprising an anine composition in a charge generation layer . Embedded image (However, in the formula, the nitro group is substituted at the 1-position or the 4-position, the 8-position or the 11-position, the 15-position or the 18-position, and the 22-position or the 25-position, respectively.) 2. An electrophotographic photoreceptor having a charge generation layer and a charge transport layer sequentially laminated on a conductive support, wherein tetranitrocopper phthalocyanine (B) and copper phthalocyanine represented by Chemical Formula 2 are simultaneously treated. To change the crystal form to α-form , and the cleavage of the tetranitro copper phthalocyanine (B)
Α-type copper phthalocyanate whose content is 1% by weight or more and 10% by weight or less
An electrophotographic photoreceptor comprising an anine composition in a charge generation layer . Embedded image (However, in the formula, the nitro group is substituted one by one at the 2- or 3-position, 9- or 10-position, 16- or 17-position, and 23- or 24-position, respectively.) 3. A conductive support a charge generating layer on the body, in the charge transporting layer are sequentially laminated electrophotographic photoreceptor comprising the Te <br/> Toranitoro copper phthalocyanine (A), the tetranitro copper phthalocyanine (B) and copper phthalocyanine simultaneously processed by changing the crystalline form to form alpha, and said tetra
The proportion of nitro copper phthalocyanine (A) is 15% by weight or less
And a percentage of the tetranitro copper phthalocyanine (B)
Not more than 8% by weight,
Anine (A) and the above-mentioned tetranitro copper phthalocyanine
Α-type copper phthalocyanine whose sum with (B) is 20% by weight or less
A photoconductor for electrophotography , comprising a charge generation layer containing a nin composition . 4. The α-type copper phthalocyanine composition wherein the crystal form has been changed to α-type by treating with an acid paste method. The photoconductor for electrophotography according to the above.