JP3138534B2 - 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 method of laminating a photosensitive layer comprising a photoconductive substance using an .alpha.-type copper phthalocyanine composition comprising tetranitro copper phthalocyanine having a specific structure and copper phthalocyanine on a photosensitive layer containing a pigment. To a positively charged electrophotographic photoconductor.

[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.

[0003] On the other hand, there is also a single-layer type photoreceptor in which a pigment having light sensitivity at a light source wavelength is dispersed in a binder resin, and an azo pigment, a quinacridone pigment, a perylene pigment, an anthraquinone pigment or a phthalocyanine pigment is used. Have been.

[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.

[0005] Single layer type photosensitive material in which a pigment is dispersed in a binder resin, the photosensitivity is a photoreceptor of positively charged is low or chargeability deteriorates due to repeated use, the sensitivity shift, durability is not sufficient And other issues.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor having improved photosensitivity and excellent durability in a positively charged photoreceptor.

[0007]

The electrophotographic photoreceptor of the present invention comprises an α-type copper phthalate on a first photosensitive layer containing a pigment.
Do not laminate a second photosensitive layer containing a cyanine composition.
Α-type copper phthalocyanine composition is tetranitro copper
Simultaneous treatment of Russiannin (A) and copper phthalocyanine
The crystal form was changed to α-form by tetranitro
The proportion of copper phthalocyanine (A) is 2% by weight or more and 20% by weight
% Or less.

[0008]

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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 an α-type copper phthalocyanine composition on a first photosensitive layer containing a pigment.
Layered with a second photosensitive layer containing
The Russiannin composition is tetranitro copper phthalocyanine
(B) and copper phthalocyanine are simultaneously treated to form a crystal form
It has been changed to α-type,
The proportion of anine (B) is 1% by weight or more and 10% by weight or less.
It is characterized by that.

[0011]

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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. )

The electrophotographic photoreceptor of the present invention further comprises an α-type copper phthalocyanine group on the first photosensitive layer containing a pigment.
A second photosensitive layer containing
Talocyanine composition is tetranitro copper phthalocyanine
(A), tetranitro copper phthalocyanine (B), and
Simultaneous treatment of copper phthalocyanine to change crystal form to α-form
It is a tetranitro copper phthalocyanine
(A) is 15% by weight or less, and tetranitro copper
The proportion of phthalocyanine (B) is 8% by weight or less,
Tetranitro copper phthalocyanine (A) and tetranitro
The sum with copper phthalocyanine (B) is 20% by weight or less
It is characterized by the following.

The α-type copper phthalocyanine composition used in the present invention includes copper phthalocyanine and tetranitro copper phthalate.
Russianin (A), copper phthalocyanine and tetranitro copper
Phthalocyanine (B), or copper phthalocyanine and tet
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 photosensitivity 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 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.

In the electrophotographic photoreceptor of the present invention, the pigment contained in the first photosensitive layer efficiently converts the carrier formed in the α-type copper phthalocyanine composition contained in the second photosensitive layer by light irradiation. Any pigment may be used as long as it is injected and transported. Possible pigments include:
Examples include phthalocyanine pigments, perylene pigments, anthraquinone pigments, squarium pigments, azo pigments, quinacridone pigments and the like. Further, a low molecular charge transport material or an α-type copper phthalocyanine composition used for the second photosensitive layer may be added to the first photosensitive layer containing a pigment. As the low molecular charge transporting substance to be added, a hydrazone compound, a styryl compound, a triphenylamine compound or the like is used.

The photoreceptor for electrophotography of the present invention is prepared by dispersing an α-type copper phthalocyanine composition and a pigment in a binder resin and applying the resulting mixture 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. The electrophotographic photosensitive member on the conductive support 1, the binder resin in which a pigment is dispersed 2 to form a first photosensitive layer 3 by coating, alpha-type copper phthalocyanine composition thereon 4
Is coated with a binder resin in which the second photosensitive layer 5 is dispersed.
Is formed.

[0022] the photosensitive layers 3 and 5, flexible within a range not to impair the photoreceptor characteristics, adhesive property, a plasticizer for improving the mechanical strength, or antioxidants such as for chemical strength improvement May be used. Further, if necessary, an intermediate layer for the purpose of improving the adhesion to the substrate and preventing injection of electrons from the substrate, or a surface protective layer for improving the mechanical properties may be provided.

The coating of the photosensitive layers 3, 5, 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.

In the case of the electrophotographic photosensitive member shown in FIG. 2, photosensitive layer 3
Has a thickness of 5 to 50 μm, preferably 10 to 20 μm. The thickness of the photosensitive layer 5 is 0.2 to 5 μm, preferably 0.1 to 5 μm.
5 to 2 μm. Further, when an intermediate layer or a surface protective layer is provided, its 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.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments.

Example 1 α-type copper phthalocyanine was prepared by an acid paste method using 10 g of copper phthalocyanine as a pigment. A polymer solution obtained by dissolving 5 g of the α-type copper phthalocyanine 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-evaporated polyester film with a wire bar, and a first photosensitive layer having a thickness of 16 μm after drying was formed.

Next, 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 l of ice water to obtain an α-type copper phthalocyanine composition. Was. A dispersion composed of 1 g of the obtained α-type copper phthalocyanine composition, 4 g of a polyester resin, and 36 g of cyclohexanone was similarly prepared and coated on the first photosensitive layer, and the sum of the thicknesses of the first and second photosensitive layers was obtained. Was adjusted to 17 μm after drying to prepare an electrophotographic photoreceptor.

The electrophotographic photoreceptor thus produced 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 characteristics of the photoreceptor. 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 = 806 V tD = 18 seconds E 1/2 = 1.9 μJ / cm ² Vr = 43 V V ₀ (1000) = 800 V tD (1000) = 17 seconds E 1/2 (1000) = 1.7 μJ / cm ² Vr (1000) = 48V

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

V ₀ = 800 V t D = 18 seconds E 1/2 = 1.4 μJ / cm ² Vr = 38 V V ₀ (1000) = 796 V t D (1000) = 17 seconds E 1/2 (1000) = 1.3 μJ / cm ² Vr (1000) = 42V

Comparative Example 1 α-type copper phthalocyanine was obtained by an acid paste method using 10 g of copper phthalocyanine. A polymer solution obtained by dissolving 5 g of this α-type copper phthalocyanine and 180 g of a polyester resin in 180 g of cyclohexanone was mixed and dispersed with 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 16 μm after drying was formed, thereby producing a photoconductor for electrophotography. 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 = 793 V t D = 17 sec E 1/2 = 45.7 μJ / cm ² Vr = 274 V V ₀ (1000) = 357 V Vr (1000) = 204 V

Comparative Example 2 Instead of the α-type copper phthalocyanine composition, tetranitro copper phthalocyanine (B) was simply mixed with the α-type copper phthalocyanine obtained by the acid paste method so as to have the same addition amount as in Example 2. A photoconductor for electrophotography was produced under the same conditions as in Example 2 except that the photoconductor was used. The photoreceptor characteristics were as follows. As described below, the chargeability was low, the photosensitivity was almost nil, and it was not practical.

V ₀ = 165 V Vr = 69 V

Example 3 An electrophotographic photosensitive member was produced under the same conditions as in Example 2 except that the binder resin for dispersing the α-type copper phthalocyanine composition and the pigment was a thermosetting melamine resin. Exposure
The body characteristics were as follows.

V ₀ = 878 V t D = 17 sec E 1/2 = 1.5 μJ / cm ² Vr = 46 V V ₀ (1000) = 860 V t D (1000) = 16 sec E 1/2 (1000) = 1.4 μJ / cm ² Vr (1000) = 49V

Example 4 An electrophotographic photosensitive member was produced under the same conditions as in Example 2 except that the first photosensitive layer was formed in place of the perylene pigment represented by Chemical Formula 5. Photoreceptor characteristics were as follows.

[0040]

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V ₀ = 738 V t D = 14 seconds E 1/2 = 2.4 μJ / cm ² Vr = 68 V V ₀ (1000) = 728 V t D (1000) = 11 seconds E 1/2 (1000) = 2.1 μJ / cm ² Vr (1000) = 73V

Comparative Example 3 An electrophotographic photoreceptor was produced under the same conditions as in Example 1 except that the perylene pigment shown in Chemical formula 5 was used instead of the α-type copper phthalocyanine composition. The photoreceptor characteristics were as follows. As described below, the photosensitivity was extremely low and was not suitable for practical use.

V ₀ = 725V tD = 23 seconds Vr = 412V

Example 5 An electrophotographic photosensitive member was produced under the same conditions as in Example 1 except that the first photosensitive layer was formed in place of the pigment represented by Chemical formula 6. The photoreceptor characteristics were as follows.

[0045]

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V ₀ = 721 V tD = 16 seconds E 1/2 = 3.2 μJ / cm ² Vr = 75 V V ₀ (1000) = 714 V tD (1000) = 18 seconds E 1/2 (1000) = 3.4 μJ / cm ² Vr (1000) = 73V

Comparative Example 4 An electrophotographic photoreceptor was produced under the same conditions as in Example 5 except that the pigment represented by Chemical formula 6 was used instead of the α-type copper phthalocyanine composition. The photoreceptor characteristics were as follows. As described below, the photosensitivity was extremely low and was not suitable for practical use.

V ₀ = 733V tD = 31 seconds Vr = 481V

Example 6 The same procedure as in Example 1 was carried out except that an α-type copper phthalocyanine composition comprising 4% by weight of tetranitrocopper phthalocyanine (A), 1% by weight of tetranitrocopper phthalocyanine (B) and copper phthalocyanine was used. Under the conditions, an electrophotographic photoreceptor was prepared. The photoreceptor characteristics were as follows.

V ₀ = 752 V tD = 16 seconds E 1/2 = 2.6 μJ / cm ² Vr = 75 V V ₀ (1000) = 738 V tD (1000) = 14 seconds E 1/2 (1000) = 2.2 μJ / cm ² Vr (1000) = 81V

[0051] (Example 7) perylene Pigments represented by Formula 5 as a pigment, a hydrazone compound represented by Chemical Formula 7 as a low-molecular charge transport material perylene
First sensing using what was added 5% by weight with respect to emissions pigment
An electrophotographic photoreceptor was produced under the same conditions as in Example 2 except that an optical layer was produced . The photosensitive characteristics were as follows.

[0052]

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V ₀ = 726 V t D = 14 sec E 1/2 = 2.0 μJ / cm ² Vr = 61 V V ₀ (1000) = 718 V t D (1000) = 13 sec E 1/2 (1000) = 1.8 μJ / cm ² Vr (1000) = 70V

Comparative Examples 5 to 9 Next, an α-type copper phthalocyanine composition in which the contents of tetranitro copper phthalocyanine (A) and (B) were changed was used, and a thermosetting melamine resin was used as a binder resin. Prepared an electrophotographic photoconductor in the same manner as in Example 1, and evaluated the photoconductor characteristics. Table 1 shows the results.

[0055]

[Table 1]

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

[0057]

The photosensitivity of the photoreceptor can be dramatically improved by laminating a photoconductive layer containing an α-type copper phthalocyanine composition on a photoconductive layer containing a pigment. Further, the α-type copper phthalocyanine composition used in the present invention is chemically stable and therefore has excellent durability. Further, since it is a positively charged 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. The electrophotographic photoreceptor of the present invention has an α-type copper phthalocyanine composition used for the upper layer, which has a broad absorption from the visible region to the infrared region. Therefore, 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 is a light source because it has high sensitivity and exhibits an induction phenomenon peculiar to the pigment dispersion type photoreceptor in a very low light quantity 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 pigment 3 first photosensitive layer 4 α-type copper phthalocyanine composition 5 second photosensitive layer

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

Claims (3)

(57) [Claims] 1. A method according to claim 1, wherein a second photosensitive layer containing an α-type copper phthalocyanine composition is laminated on a first photosensitive layer containing a pigment, wherein the α-type copper phthalocyanine composition is represented by the following chemical formula 1. The tetranitro copper phthalocyanine (A) and the copper phthalocyanine are simultaneously treated to change the crystal form to the α-form, and the tetranitro copper phthalocyanine (A)
Is 2% by weight or more and 20% by weight or less. 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. A second photosensitive layer containing an α-type copper phthalocyanine composition is laminated on a first photosensitive layer containing a pigment, wherein the α-type copper phthalocyanine composition comprises the tetranitro copper phthalocyanine ( A), tetranitrocopper phthalocyanine (B), and copper phthalocyanine are simultaneously treated to change the crystal form to α-form, wherein the proportion of tetranitrocopper phthalocyanine (A) is 15% by weight or less, An electrophotographic photosensitive material, wherein the proportion of copper phthalocyanine (B) is 8% by weight or less, and the sum of said tetranitro copper phthalocyanine (A) and said tetranitro copper phthalocyanine (B) is 20% by weight or less. body. Embedded image (However, if the nitro group in the formula is 2-, 3-, or 9-position
10th, 16th or 17th and 23rd
Or one at position 24. ) 3. A α type copper phthalocyanine composition according to claim 1 or claim 2 electrophotographic photosensitive member according to, characterized in that changing the crystalline form to form α by treatment with acid paste method.