JP3137418B2 - 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 monolayer type electrophotographic photoreceptor using an .alpha.-type copper phthalocyanine composition comprising tetranitrocopper phthalocyanine and copper phthalocyanine having a specific structure as a photoconductive substance.

[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. . In this case, a hydrazone compound, a styryl compound, a pyrazoline compound, a triphenylamine compound, or the like, which is a low-molecular conductive material, is used as the charge transport material.

On the other hand, there is also a single-layer type photoreceptor in which a pigment having photosensitivity at the wavelength of the light source is dispersed in a binder resin, and phthalocyanine is often used for the photoreceptor.

[0004]

In the case of the function-separated type photoreceptor, since most of the charge transporting substances are of the hole transporting type, most of them are of the negative charging type. In the case of the negative charging type, there are problems such as deterioration of the photoreceptor due to generation of ozone and effects on the environment and the human body.

On the other hand, a single-layer type photoreceptor using phthalocyanine as a photoconductive substance is a positively charged type photoreceptor, but has a low photosensitivity as a photoreceptor, and deteriorates charging ability due to repeated use, and sensitivity. Satisfaction has not yet been obtained due to shifts and the like.

An object of the present invention is to provide a positively charged single-layer type electrophotographic photoreceptor which uses phthalocyanine as a photoconductive substance, generates a small amount of ozone, has high photosensitivity, and has excellent durability. It is.

[0007]

The electrophotographic photoreceptor of the present invention comprises an α-type copper phthalocyanine composition obtained by simultaneously treating tetranitro copper phthalocyanine (A) and copper phthalocyanine to change the crystal form into α-type. A photoconductive substance, wherein the ratio of tetranitro copper phthalocyanine (A) to the α-type copper phthalocyanine composition is 2% by weight or more and 2% by weight or more.
0 wt% or less.

[0008]

Embedded image

(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 is characterized in that an α-type copper phthalocyanine composition obtained by simultaneously treating tetranitro copper phthalocyanine (B) and copper phthalocyanine to change the crystal form into α-type is a photoconductive substance. Wherein the ratio of tetranitro copper phthalocyanine (B) to the α-type copper phthalocyanine composition is 1% by weight or more and 10% by weight or less.

[0011]

Embedded image

(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. )

Further, the electrophotographic photoreceptor of the present invention comprises an α-type copper phthalocyanine composition obtained by simultaneously treating tetranitrocopper phthalocyanine (A), tetranitrocopper phthalocyanine (B), and copper phthalocyanine to change the crystal form to α-type. Wherein the proportion of tetranitro copper phthalocyanine (A) to the α-type copper phthalocyanine composition is 15% by weight or less and the proportion of tetranitro copper phthalocyanine (B) is 8% by weight or less with respect to the α-type copper phthalocyanine composition. And the sum of tetranitro copper phthalocyanine (A) and tetranitro copper phthalocyanine (B) is 20% by weight or less.

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, tetranitro copper phthalocyanine (A) and tetranitro copper Preferably, the phthalocyanine (B) is simultaneously treated by the acid paste method to change the crystal system 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.

The photoreceptor for electrophotography of the present invention can change photosensitivity 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 tetranitro copper phthalocyanine (A) and / or tetranitro copper phthalocyanine (B) in the α-type copper phthalocyanine composition is less than the above range, the photosensitivity as a photoreceptor is low, and when the content is large, the charging ability is low. Has dropped extremely,
Neither case is practical.

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 most preferable. Is the way.
However, even if tetranitro copper phthalocyanine is simply mixed with α-type copper phthalocyanine, the desired photoreceptor characteristics cannot be obtained.

FIG. 1 shows an X-ray diffraction pattern of the α-type copper phthalocyanine composition used in the present invention. The position of each peak coincides with that of normal α-type copper phthalocyanine.

The photoreceptor for electrophotography of the present invention is prepared by dispersing an α-type copper phthalocyanine composition in a binder resin and applying this to a conductive support. As the binder resin, besides thermoplastic resins such as polyester resin, polycarbonate resin, polyvinyl butyral resin, etc., thermosetting resins such as polyurethane resin, epoxy resin, melamine resin, formalin resin, phenol resin, etc. High resin is used.

FIG. 2 shows an example of the form of the electrophotographic photosensitive member of the present invention. FIG. 2 is a sectional view of the electrophotographic photosensitive member of the present invention. This electrophotographic photoreceptor is prepared by applying a binder resin in which an α-type copper phthalocyanine composition 3 is dispersed as a photosensitive layer 2 on a conductive support 1.

The photosensitive layer 2 is formed by using a plasticizer for improving flexibility, adhesion, and mechanical strength as long as the photoreceptor characteristics are not impaired, or using an antioxidant for improving chemical strength. Is also good. Also, if necessary, an intermediate layer for the purpose of improving adhesion to the substrate, preventing electron injection from the substrate,
Alternatively, a surface protective layer for improving mechanical properties may be provided.

The coating of the photosensitive layer 2, the intermediate layer and the surface protective layer is usually carried out using a doctor blade, a wire bar, a roll coater or the like.

The thickness of the photosensitive layer 2 is 5 to 50 μm, preferably 10 to 20 μm in the case of the electrophotographic photosensitive member shown in FIG. When further providing an intermediate layer or a surface protective layer,
The thickness is preferably 1 μm or less.

As the conductive support 1, those conventionally used can be used. Specifically, a metal support such as aluminum, stainless steel, copper, or brass, or a support obtained by depositing aluminum, indium oxide, or the like on an insulating support may be used.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. (Example 1) 9.2 g of copper phthalocyanine and 0.8 g (8% by weight) of tetranitro copper phthalocyanine (A) were dissolved in 100 g of sulfuric acid, and this solution was poured into 2 liters of ice water to obtain an α-type copper phthalocyanine composition. Was. A polymer solution obtained by dissolving 5 g of the α-type copper phthalocyanine composition and 20 g of a polyester resin in 180 g of cyclohexanone was mixed and 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 photosensitive layer having a thickness of 17 μm after drying was formed.

The electrophotographic photoreceptor thus prepared was corona-charged at +6 KV in a dark place, and then exposed to a W lamp having an illuminance of 2.5 μW / cm ² for 20 seconds to examine the photoreceptor characteristics. The photoreceptor characteristics include an initial charging potential V ₀ after charging, a time tD required for the surface potential to darkly attenuate from 620 V to 600 V, an exposure amount E1 / 2 required to attenuate light from 600 V to 300 V, and a 20 second light. The residual potential Vr after the irradiation was measured. Further, the same operation was repeated on the electrophotographic photoreceptor to obtain V ₀ (1000), t after 1000 times.
D (1000), E1 / 2 (1000), Vr (100
0) was measured, and the durability was examined. The results were as follows. FIG. 3 shows a light decay curve when light is irradiated at time t ₀ after charging. From FIG. 3, it can be seen that the electrophotographic photoreceptor of the present invention has high sensitivity and exhibits an induction phenomenon peculiar to the photoreceptor in which a pigment is dispersed in a binder resin in a very weak light amount range.

V ₀ = 780 V tD = 15 sec E 1/2 = 1.8 μJ / cm ² Vr = 36 V V ₀ (1000) = 765 V tD (1000) = 13 sec E 1/2 (1000) = 1.6 μJ / cm ² Vr (1000) = 42V

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

V ₀ = 796 V t D = 16 sec E 1/2 = 1.5 μJ / cm ² Vr = 30 V V ₀ (1000) = 779 V t D (1000) = 14 sec E 1/2 (1000) = 1.3 μJ / cm ² Vr (1000) = 40V

(Comparative Example 1) An electrophotographic photoreceptor was manufactured under the same conditions as in Example 1 except that a normal α-type copper phthalocyanine obtained by an acid paste method was used as a photoconductive substance. The photoreceptor characteristics were as follows. As described below, the initial photosensitivity was extremely low, and the charging ability was rapidly reduced by repeated use, which was not suitable for practical use.

V ₀ = 765 V tD = 13 seconds E 1/2 = 43.3 μJ / cm ² Vr = 283 V V ₀ (1000) = 321 V Vr (1000) = 134 V

(Comparative Example 2) A photoconductive substance was obtained by mixing tetraα copper phthalocyanine (B) with ordinary α-type copper phthalocyanine obtained by the acid paste method in the same amount as in Example 2. Otherwise, Example 1
Under the same conditions as in the above, an electrophotographic photoconductor was prepared. The photoreceptor characteristics were as follows. The charging ability is low as below,
It had almost no light sensitivity and was not suitable for practical use.

V ₀ = 196 V Vr = 121 V

Example 3 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. The photoreceptor characteristics were as follows.

V ₀ = 867 V tD = 18 seconds E 1/2 = 1.6 μJ / cm ² Vr = 43 V V ₀ (1000) = 841 V tD (1000) = 16 seconds E 1/2 (1000) = 1.4 μJ / cm ² Vr (1000) = 50V

Example 4 An electrophotographic photosensitive member was produced under the same conditions as in Example 2 except that a thermosetting melamine resin was used as a binder resin. The photoreceptor characteristics were as follows.

V ₀ = 872 V tD = 16 seconds E 1/2 = 1.2 μJ / cm ² Vr = 38 V V ₀ (1000) = 869 V tD (1000) = 16 seconds E 1/2 (1000) = 1.1 μJ / cm ² Vr (1000) = 43V

Example 5 An α-type copper phthalocyanine composition containing 4% by weight of tetranitro copper phthalocyanine (A) and 1% by weight of tetranitro copper phthalocyanine (B) was used, and a thermosetting melamine resin was used as a binder resin. An electrophotographic photoconductor was manufactured under the same conditions as in Example 1 except for the above. The photoreceptor characteristics were as follows.

V ₀ = 836 V tD = 16 seconds E 1/2 = 1.0 μJ / cm ² Vr = 32 V V ₀ (1000) = 824 V tD (1000) = 16 seconds E 1/2 (1000) = 0.9 μJ / cm ² Vr (1000) = 36V

(Comparative Examples 3 to 7) Next, using an α-type copper phthalocyanine composition in which the content of tetranitrocopper phthalocyanine (A) or (B) was changed, electrophotography was performed in the same manner as in Example 1. A photoconductor was prepared and its photoconductor characteristics were evaluated. Table 1 shows the results.

[0041]

[Table 1]

From the results in Table 1, the tetranitro copper phthalocyanine (A) for the α-type copper phthalocyanine composition,
When the content of (B) is less than the range of the present invention, the photosensitivity as a photoreceptor is low, and when it is large, the charging ability is extremely reduced, and it is understood that both are not suitable for practical use.

[0043]

The α-type copper phthalocyanine composition used in the present invention has high sensitivity and is chemically stable as compared with ordinary α-type copper phthalocyanine, and therefore has excellent durability.
Further, since it is a positive charging type, the amount of ozone generated by charging is small, and a high printing durability electrophotographic photoreceptor having high sensitivity and excellent durability can be provided by selecting a binder resin or the like. Further, since the α-type copper phthalocyanine composition used in the electrophotographic photoreceptor of the present invention has a wide absorption from the visible region to the infrared region, a laser printer, a liquid crystal shutter printer, an LED printer, a copying machine, an electrophotographic plate making system, etc. It can also be applied to

The electrophotographic photoreceptor of the present invention using the α-type copper phthalocyanine composition has high sensitivity and exhibits an induction phenomenon peculiar to the pigment-dispersed single-layer type photoreceptor in a very low light amount range. It can also be used as a high-resolution electrophotographic photoreceptor that is not affected by the light leakage of the liquid crystal shutter and the light distribution at the edge of the irradiation light spot.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction diagram of an α-type copper phthalocyanine composition used in the present invention.

FIG. 2 is a cross-sectional view of the electrophotographic photoconductor of the present invention.

FIG. 3 is a diagram showing a light decay curve of the electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

 Reference Signs List 1 conductive support 2 photosensitive layer 3 α-type copper phthalocyanine composition

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 5/00-5/16

Claims (4)

(57) [Claims] 1. An electrophotographic material comprising an α-type copper phthalocyanine composition obtained by simultaneously treating a tetranitrocopper phthalocyanine (A) and copper phthalocyanine of formula 1 to change the crystal form into α-type, as a photoconductive substance. In the photoreceptor, the α
Ratio of the tetranitro copper phthalocyanine for type copper phthalocyanine composition (A) is 2 wt% to 20 wt%
A photoconductor for electrophotography, comprising: 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 material comprising an α-type copper phthalocyanine composition obtained by simultaneously treating a tetranitrocopper phthalocyanine (B) and copper phthalocyanine of formula 2 to change the crystal form to α-type, as a photoconductive substance. In the photoreceptor, the α
Ratio of the tetranitro copper phthalocyanine for type copper phthalocyanine composition (B) is 1 wt% to 10 wt%
A photoconductor for electrophotography, comprising: 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. An α-type copper phthalocyanine composition obtained by simultaneously treating said tetranitrocopper phthalocyanine (A), said tetranitrocopper phthalocyanine (B), and copper phthalocyanine to change the crystal form into α-type, comprising a photoconductive substance. Electrophotographic photoreceptor, the α-type copper phthalocyanine
Ratio of the tetranitro copper phthalocyanine for cyanine composition (A) is 15 wt% or less, the Tetorani <br/> is the proportion of the Toro copper phthalocyanine (B) is 8 wt% or less, and the tetranitro copper phthalocyanine (A ) And before
An electrophotographic photoreceptor , wherein the sum with the tetranitro copper phthalocyanine (B) is 20% by weight or less. 4. The electron according to claim 1, wherein the α-type copper phthalocyanine composition whose crystal form has been changed to α-type by treating with an acid paste method is a photoconductive substance. Photoreceptor.