JPH07128892A - Positive electrification type electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To improve corona resistance without deteriorating such characteristics as dark attenuation and photosensitivity by forming a photosensitive layer dispersedly contg. particles of a photoconductive phthalocyanine compd. surface- treated with a coupling agent in a resin binder. CONSTITUTION:A polyamide resin layer as an undercoat layer is formed on a polished Al plate by dipping in a methanol soln. and drying to obtain a substrate 1 for a photoreceptor. The surfaces of particles of X type metal-free phthalocyanine as a photoconductive phthalocyanine compd. are treated with a silane coupling agent by putting the phthalocyanine and the coupling agent in toluene. A photosensitive layer 2 contg. the photoconductive phthalocyanine compd. 20 dispersed in a resin binder 21 is then formed on the substrate 1 by dip coating with a photosensitive liq. The surfaces of the particles of the compd. 20 have been treated with the coupling agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoconductor used in electrophotographic copying machines and printers.

[0002]

2. Description of the Related Art In electrophotographic recording used in copiers, printers, etc., the surface of a photosensitive layer of a photoconductor is charged and then exposed to form an electrostatic latent image, which is visualized with a toner ( It is a method of developing an image, transferring a visible image to paper or the like, and fixing the image to obtain an image. Thereafter, the photoconductor is subjected to surface cleaning (cleaning) such as removal of adhered toner and charge removal, and is repeatedly used many times.

Therefore, in addition to electrophotographic characteristics such as good charging characteristics and photosensitivity and small dark decay, the electrophotographic photosensitive member has a small change in the electrophotographic characteristics with repeated use, and printing durability. It is required to have excellent physical properties such as resistance, abrasion resistance, and moisture resistance, and excellent chemical resistance to ozone, NO _x, etc. generated during charging.

Conventionally, selenium has been used as an electrophotographic photoreceptor.
Although inorganic materials such as cadmium sulfide and zinc oxide have been used, the brightness of the exposure source has been increased due to the problem of material toxicity and the speeding up of copying machines and printers.
Organic photoconductor materials have come to be used more and more for the purpose of lengthening the photosensitivity wavelength by using EDs. On the other hand, due to the problem of health maintenance of equipment users, much attention has been paid to positively charged organic photoconductors that can minimize the amount of ozone generated during corona charging.

The advantage of using a phthalocyanine-based photoconductive compound as the positively chargeable organic light-sensitive material is described in, for example, US Pat. No. 3,816,118 and JP-B-49.
It is well known as disclosed in Japanese Patent Publication No. 4338.
That is, the phthalocyanine-based compound not only has a large light absorption property, excellent heat resistance, chemical resistance, and light resistance, but also has a large photoconductivity upon irradiation with light, that is, an excellent generation efficiency of electron-hole pairs. .

A positive charging type photoreceptor using a phthalocyanine-based compound is usually provided with an undercoat layer on an aluminum drum, followed by a photosensitive layer having phthalocyanine-based photoconductive compound particles dispersed in a resin. It has become. In this way, the basic configuration is extremely simple.

[0007]

The conventional positive charge type organic photoconductor using the phthalocyanine photoconductive compound has the above-mentioned constitution, and the amount of ozone generated is generated by charging the photoconductor by the positive corona. However, it has a drawback that it is very weak in ozone resistance, and the life of the photoconductor is remarkably reduced under the conditions of repeated use and temperature and humidity with a high ozone generation rate. Had to take sufficient measures against ozone such as ventilation around the photoconductor.

As a method for solving this problem, the first method that can be easily considered is to provide an overcoat layer on the photoconductor layer so that the photoconductor is not directly exposed to the ozone atmosphere. Providing an overcoat layer is also described in the above-mentioned US Pat. No. 3,816,118, but its main purpose is to provide a physical protective film for the photoreceptor,
In other words, the present inventors have confirmed that the printing durability, the abrasion resistance, the moisture resistance and the like are improved, and that they are effective in this respect. However, it has been confirmed that the provision of the overcoat layer causes a harmful effect.
That is, the photosensitivity of the photoreceptor is lowered by the overcoat layer, and the photosensitivity changes with time when the overcoat layer is mechanically scraped in the printing durability test. Moreover, it has been found that the ozone resistance, which is a problem here, is not necessarily blocked by the overcoat layer. That is, it was experimentally confirmed that when exposed to an ozone atmosphere for a long time, ozone penetrates the overcoat layer and enters the photoreceptor layer, and adversely affects the characteristics of the photoreceptor.

The present inventors have investigated the mechanism of the deterioration of the photoconductor by ozone in detail, and have found that the chemically defective portion in the photoconductor is selectively attacked by ozone. Here, the chemical defect portion in the photoreceptor is a structural defect of the phthalocyanine-based compound, which is a photoconductive material,
For example, it is a state in which one atom such as hydrogen is missing, and structural defect parts of the binder resin. These defective parts are usually long-lived ionic or radical active species and are stable in normal conditions. However, these defective portions tend to be easily decomposed by highly reactive ozone or the like. If a defect-free photoconductor can be manufactured, the ozone problem can be solved, but it is not economically practical to manufacture a photoconductor using a pure, defect-free material alone.

The present invention has been made in order to solve such an ozone problem, and it is practical without deteriorating the electrophotographic characteristics such as charging property, photosensitivity (photoresponsiveness), and dark decay. In addition, it is intended to improve the durability of ozone generated during charging.

[0011]

A positively charged electrophotographic photoreceptor according to claim 1 of the present invention comprises a binder resin containing a phthalocyanine photoconductive compound having a particle surface treated with a coupling agent. To form a photosensitive layer.

The positively chargeable electrophotographic photoreceptor according to claim 2 of the present invention has a photosensitive layer whose surface is treated with a coupling agent.

The positive charging type electrophotographic photoreceptor according to claim 3 of the present invention is the positive charging type electrophotographic photoreceptor according to claim 1 or 2, wherein an antioxidant or an ozone decomposing compound is present in the photosensitive layer. Is added.

The positively charged electrophotographic photoreceptor according to claim 4 of the present invention uses a silane or titanate coupling agent as the coupling agent.

According to a fifth aspect of the present invention, there is provided a positively-charged electrophotographic photosensitive member in which the surface of the photosensitive layer is subjected to a hydrophobic treatment.

The positive charging type electrophotographic photoreceptor according to claim 6 of the present invention uses a fluorine-based compound as a hydrophobizing agent.

According to a seventh aspect of the present invention, there is provided a positively chargeable electrophotographic photoconductor in which a protective layer containing an antioxidant or an ozone decomposable compound is provided on the photosensitive layer.

The positively charged electrophotographic photoreceptor according to claim 8 of the present invention uses an active oxygen quencher as an ozone decomposing compound.

According to a ninth aspect of the present invention, there is provided a positively charged type electrophotographic photoconductor in which a phthalocyanine-based photoconductive compound is an X-type crystal of a metal-free phthalocyanine having an average particle size of 0.5 μm or less. 15 to 40% by weight is dispersed, and the film thickness of the photosensitive layer is 10 to 30 μm.

[0020]

The coupling treatment on the particle surface of the phthalocyanine-based photoconductive compound according to claims 1 and 4 of the present invention can suppress the deterioration of the photosensitive layer due to a chemical change. It protects the active points that decompose and makes it possible to stabilize the image quality even with continuous use.

Further, a coupling treatment of the surface of the photosensitive layer according to claims 2 and 4 of the present invention, or claims 5 and 6
The hydrophobic treatment on the surface of the photosensitive layer in the same manner as in claim 1 can suppress deterioration of the photosensitive layer due to a chemical change, and can further protect the active sites where the processing agent decomposes by ozone or the like. The image quality can be stabilized by using it.

The antioxidant and the ozone decomposable compound according to claims 3, 7 and 8 of the present invention are ozone, NO.
_It effectively absorbs active species such as _X and effectively prevents the deterioration of the photosensitive layer. The amount added to these photosensitive layer or protective layer has an optimum value range (both 0.01 to 5.0 wt% / per solid content). Within this range, the characteristics of the photosensitive member are not impaired and Deterioration can be effectively prevented. When these are too small, their functions become insufficient, and when they are too large, responsiveness deteriorates.

Further, in the positively charged electrophotographic photoreceptor according to claim 9 of the present invention, the phthalocyanine photoconductive compound is an X-type crystal of metal-free phthalocyanine. In the metal phthalocyanine, the phthalocyanine is ideally coordinated with the metal to maintain electrical neutrality, but in reality, a defective portion is likely to occur and that portion is easily oxidized by ozone. On the other hand, metal-free phthalocyanine has only small hydrogen atoms coordinated thereto, and coordination defects are less likely to occur. Further, the smaller the particle size of the phthalocyanine-based photoconductive compound, the better the dispersion. Further, the compounding ratio of the phthalocyanine-based photoconductive compound in the photoreceptor is 15
It is necessary to be ˜40%. This is a necessary condition for the photoconductor to function as a positive charging type photoconductor.
When it is less than this range, the photosensitivity is remarkably lowered, and when it is more than this range, the bulk resistance of the photoreceptor is lowered and the charge retention ability is lowered. The most preferable range is 25 to 35% in terms of the balance between photosensitivity and charge retention ability. Further, the thickness of the photosensitive layer needs to be in the range of 10 to 30 μm. If it is thinner than this, the charge retention ability is lowered, pinholes are easily generated, and mechanical properties such as printing durability are deteriorated. It will drop significantly. On the other hand, if the thickness is thicker than this range, the photoresponse speed will be insufficient, and the amount of expensive photoconductive material used will increase, which is uneconomical. Considering the charge retention ability, the photoresponse speed, etc., the most preferable range of the film thickness is 15 to 25 μm.

[0024]

【Example】

Example 1. 1A and 1B are explanatory views showing a photoconductor according to Example 1 of the present invention, in which 1 is a substrate and 2 is a photosensitive layer. The photosensitive layer 2 is a phthalocyanine-based photoconductive compound 2
0 is a layer dispersed in the binder resin 21, and in this embodiment, the particle surface of the phthalocyanine photoconductive compound 20 is treated with a coupling agent as shown in FIG. 1 (b).

Next, this embodiment will be described more specifically. A polyamide resin layer having an average film thickness of 0.5 μm was applied as an undercoat layer to a polished aluminum plate by dipping and coating in a solution of a methanol solution, and dried to form a photoconductor substrate 1. Next, using X-type metal-free phthalocyanine as a phthalocyanine-based photoconductive compound, 15 g of this X-type metal-free phthalocyanine and a silane coupling agent (KBM-603 manufactured by Shin-Etsu Chemical Co., Ltd.) were put in 130 g of toluene, and dispersed with a paint shaker for 2 hours. Then, the surface of the phthalocyanine particles was subjected to silane coupling treatment. Then, 27.9 g of polyester resin, 6.98 g of butylated melamine resin, and 130 of MEK (methyl ethyl ketone).
g was added and dispersed for 2 hours to prepare a photosensitive solution. At this time, the addition amount of silane coupling was 0.03 wt% based on the solid content. The photosensitive solution thus obtained is applied to the photoreceptor substrate 1 (polyamide layer on an aluminum plate).
Dip coating, dry at room temperature, cure and dry at 150 ° C for 4 hours, further dip-coat in a toluene solution of 30 wt% polyester resin and butylated melamine resin (blended 4: 1), and dry at 150 ° C for 4 hours. After curing, a test piece for a photoreceptor according to an embodiment of the present invention was obtained. At this time, the photosensitive layer 2
The photosensitive solution was applied so that the film thickness was 18 to 22 μm.

This photoreceptor test piece was measured for corona resistance, dark decay characteristics and response using an electrostatic charging tester (trade name: EPA-8100, manufactured by Kawaguchi Denki Co., Ltd.).
For the corona resistance, the charging potential (V) was measured when the photoreceptor test piece was continuously charged with a constant current of +7 μA for 30 seconds, and the rate of change from the initial charging potential was obtained. The dark decay characteristics were obtained by charging the charging potential to +600 V and measuring the charging potential after the charging was stopped to obtain the amount of change. For the responsiveness, the amount of change in charging potential when irradiated with light having a wavelength of 780 nm and an exposure dose of 3 μJ / cm ² was determined. The results are shown in Table 1.
Shown in.

Example 2. In Example 1, the amount of silane coupling added was set to 0.03 wt%, whereas in this Example, the amount was set to 0.04 wt% based on the solid content, and otherwise the same process as in Example 1 was performed. A photoconductor was formed.
The results are shown in Table 1.

Example 3. In the present example, the amount of silane coupling added was 0.16 wt% based on the solid content, and the other steps were the same as in Example 1 to form the photoconductor of the present example. The results are shown in Table 1.

Example 4. FIG. 2 is an explanatory diagram showing a photoconductor according to Example 4 of the present invention, in which the surface of the photosensitive layer 2 is treated with a coupling agent.

Next, this embodiment will be described more specifically. The same photoreceptor substrate 1 as in Example 1 was used.
X-type metal-free phthalocyanine 15g, polyester resin 2
A mixed solvent of 130 g of toluene and 130 g of MEK (methyl ethyl ketone) was added to 7.9 g and 6.98 g of butylated melamine resin, and the photosensitive solution dispersed for 2 hours with a paint shaker was placed on the photosensitive substrate 1 (polyamide layer on aluminum plate). After dip coating, it was dried at room temperature and dried and cured at 150 ° C. for 1 hour. The silane coupling agent (0.03 wt% toluene diluted solution) used in Example 1 was applied onto the photosensitive layer 2 and dried and cured again at 150 ° C. for 4 hours, and further 30
wt% polyester resin, butylated melamine resin (4:
1)) and then dip coated in a toluene solution of
It was dried and cured for a period of time to obtain a test piece for the photoreceptor according to this example. At this time, the photosensitive liquid was applied so that the film thickness of the photosensitive layer 2 was 18 to 22 μm. Table 1 shows the evaluation results of this electrophotographic photoreceptor.

Example 5. In Example 1, a photoconductor in which a polyamide layer was formed on the photoconductive layer 2 as an intermediate layer was manufactured as a trial. At this time, the photoconductor test piece was manufactured in the same manner as in Example 1. Table 1 shows the evaluation results of this electrophotographic photoreceptor.

Example 6. In this example, a titanate-based coupling agent was used in place of the silane coupling agent of Example 1 to perform coupling treatment on the surface of phthalocyanine particles. That is, 15 g of X-type metal-free phthalocyanine and a titanate-based coupling agent (KR38S manufactured by Ajinomoto Co., Inc.) were put in 130 g of toluene, dispersed for 2 hours with a paint shaker, and the phthalocyanine was subjected to a coupling treatment. Then, 27.9 g of polyester resin, 6.98 g of butylated melamine resin, and 130 g of MEK (methyl ethyl ketone) were added, and the mixture was further dispersed for 2 hours to prepare a photosensitive solution. At this time, the amount of titanate-based coupling added was 0.05 wt% based on the solid content. The thus-obtained photosensitive solution was applied by dip coating on a photosensitive substrate 1 (polyamide layer on an aluminum plate) similar to that in Example 1, dried at room temperature, dried and cured at 150 ° C. for 4 hours, and further 30 wt% polyester Resin, butylated melamine resin (blended 4: 1)
Was applied by dip coating to a toluene solution of, and dried and cured at 150 ° C. for 4 hours to obtain a test piece of a photoreceptor according to an example of the present invention. At this time, the photosensitive liquid was applied so that the film thickness of the photosensitive layer 2 was 18 to 22 μm. Table 1 shows the evaluation results of this electrophotographic photoreceptor.

Example 7. In this example, a titanate coupling agent was used in place of the silane coupling agent of Example 4 to perform the coupling treatment on the surface of the photosensitive layer 2.
That is, X-type metal-free phthalocyanine 15 g, polyester resin 27.9 g, butylated melamine resin 6.98 g, toluene 130 g and MEK (methyl ethyl ketone) 130.
g of the mixed solvent was added, and the photosensitive solution dispersed for 2 hours with a paint shaker was applied by dip coating on the same photoreceptor substrate 1 (polyamide layer on aluminum plate) as in Example 4, dried at room temperature, and then at 150 ° C. for 1 hour. Dried and cured for hours. On this photosensitive layer 2, the titanate coupling agent (0.
05 wt% toluene diluted solution) and applied again at 150 ° C
4 hours by dry-curing, further dip-coating in a toluene solution of 30 wt% polyester resin, butylated melamine resin (blended at 4: 1), dry-curing at 150 ° C. for 4 hours, and sensitizing according to the embodiment of the present invention. It was used as a body test piece. At this time, the photosensitive solution was applied so that the film thickness of the photosensitive layer was 18 to 22 μm. Table 1 shows the evaluation results of this electrophotographic photoreceptor.

Example 8. FIG. 3 is an explanatory view showing a photoconductor according to Example 8 of the present invention, in which the photosensitive layer obtained in Example 1, that is, the coupling-treated phthalocyanine-based photoconductive compound 20 is dispersed in a binder resin 21. The antioxidant 23 is added to the photosensitive layer 2.

Next, this embodiment will be described more specifically. The same photoreceptor substrate 1 as in Example 1 was used.
X-type metal-free phthalocyanine and a silane coupling agent (KBM-603, manufactured by Shin-Etsu Chemical) were placed in toluene and dispersed with a paint shaker for 2 hours, and the phthalocyanine was subjected to silane coupling treatment. Then, a polyester resin and a melamine resin, MEK (methyl ethyl ketone), methanol and an antioxidant are added and dispersed for 2 hours to prepare a photosensitive solution, which is applied by dip coating on a photosensitive substrate 1 having a polyamide layer provided on an aluminum plate. Dried and cured. At this time, the addition amount of the silane coupling agent is 0.03 wt%, methanol is 1 wt%, and the antioxidant is, for example, N, N′-diphenyl-P-phenylenediamine (DPPD) 0.06 w.
t% was added. Furthermore, a 30 wt% polyester resin and a butylated melamine resin (blended to 4: 1) were applied by dip coating, and dried and cured at 150 ° C. for 4 hours to obtain a photoreceptor test piece. The phthalocyanine, the solvent, the amount of resin added, and the manufacturing method were the same as in Example 1. Table 1 shows the evaluation results of this electrophotographic photoreceptor.

Example 9. In Example 8, the antioxidant (DP
While the amount of PD) added is 0.06 wt%,
In this embodiment, 0.5 wt% was used, and the other processes were the same as in the above-described embodiment 8 to form the photoconductor of this embodiment. The results are shown in Table 1.

Example 10. In this example, an ozone decomposable compound was added to the photosensitive layer 2 instead of the antioxidant 23 of Example 8. That is, 15 g of X-type metal-free phthalocyanine and a silane coupling agent (KBM-603, manufactured by Shin-Etsu Chemical).
0.03 wt% / per solid content was put in 130 g of toluene, dispersed for 2 hours by a paint shaker, and phthalocyanine was subjected to silane coupling treatment. Then, an ozone decomposable compound, 27.9 g of a polyester resin, 6.98 g of a butylated melamine resin, and 130 g of MEK (methyl ethyl ketone) were added and further dispersed for 2 hours to prepare a photosensitive solution. As the ozonolytic compound, for example, α-tocopherol, which is an active oxygen quencher, was added, and the addition amount was set to 0.01 wt% / solid content. The photosensitive solution thus obtained is applied onto the photoreceptor substrate 1 (polyamide layer on an aluminum plate) by dip coating, dried at room temperature, dried and cured at 150 ° C. for 4 hours, and further 30 wt% polyester resin, butylated melamine. It was applied by dip coating in a toluene solution of a resin (blended to 4: 1) and dried and cured at 150 ° C. for 4 hours to obtain a photoconductor test piece. At this time, the film thickness of the photosensitive layer 2 is 18 to 22 μm.
The photosensitive solution was applied so as to have a thickness of m. Table 1 shows the evaluation results of this electrophotographic photoreceptor.

Example 11. As the ozonolytic compound in Example 10, β-carotene, which is an active oxygen quencher, may be added instead of α-tocopherol. In this example, β-carotene was added at 0.01 wt% / solid content. Was added. Otherwise, the same processes as in Example 10 were carried out to form the photoconductor of this example. The results are shown in Table 1.

Example 12 As the ozonolytic compound in Example 10, ascorbic acid, which is an active oxygen quencher, may be added instead of α-tocopherol. In this example, 0.01% by weight of ascorbic acid /
Solid content was added. Otherwise, the same processes as in Example 10 were carried out to form the photoconductor of this example. The results are shown in Table 1.

Example 13. Further, as the ozonolytic compound in Example 10, bis (dimethylaminophenyl) (aminomethyldithione) nickel, which is an active oxygen quencher, may be added instead of α-tocopherol, and the addition amount is 2 wt%. / Solid content. Otherwise, the same processes as in Example 10 were carried out to form the photoconductor of this example. The results are shown in Table 1.

Example 14 In this example, an ozone decomposable compound (ascorbic acid) was added to the photosensitive layer 2 of the photoconductor shown in Example 4. That is, a mixed solvent of 15 g of X-type metal-free phthalocyanine, 0.005 g of ascorbic acid, 0.5 g of dimethyl-β-cyclodextrin, 27.9 g of polyester resin, 6.98 g of butylated melamine resin, 130 g of toluene and 130 g of MEK (methyl ethyl ketone). Was added and dispersed with a paint shaker for 2 hours to prepare a photosensitive solution. This photosensitive solution was applied by dip coating on the photoreceptor substrate (polyamide layer on aluminum plate), dried at room temperature, and then dried and cured at 150 ° C. for 1 hour. The silane coupling agent used in Example 1 (0.01 wt.
% Toluene diluted solution) and again dried and cured at 150 ° C. for 1 hour, and further dip-coated with a toluene solution of 30 wt% polyester resin and butylated melamine resin (blended at 4: 1), and at 4 ° C. at 150 ° C. After being dried and cured for a time, it was used as a test piece for a photoreceptor according to an embodiment of the present invention. At this time, the photosensitive solution was applied so that the film thickness of the photosensitive layer was 18 to 22 μm. Table 1 shows the evaluation results of this electrophotographic photoreceptor.

Example 15. FIG. 4 is an explanatory diagram showing a photoconductor according to Example 15 of the present invention, in which a protective layer 24 to which an antioxidant 23 is added is provided on the photosensitive layer 2.

Next, this embodiment will be described more specifically. The same photoreceptor substrate 1 as in Example 1 was used.
X-type metal-free phthalocyanine 15g, polyester resin 2
A mixture of 7.9 g, butylated melamine resin 6.98 g, toluene 130 g, and MEK 130 g was dispersed with a paint shaker (manufactured by Asada Tekko Co., Ltd.) to prepare a photosensitive solution. The photosensitive liquid was applied to the photoconductor substrate 1 by a dipping method and heat-cured at 150 ° C. for 4 hours to form a photosensitive layer 2.
The film thickness of the photosensitive layer at this time was 18 to 22 μm. Furthermore, a compound (antioxidant) having a dialkylhydroxylphenyl skeleton is formed thereon as a protective layer 1,
3,5-Trimethyl-2,4,6-tris (3,5-dibutyl-4-hydroxybenzyl) benzene (melting point 24
0-245 ° C) 0.5 wt%, polyester resin 4.8
wt%, a toluene solution blended with 1.2 wt% of butylated melamine resin was applied and heat-cured to prepare a photoconductor test piece. Table 1 shows the evaluation results of this electrophotographic photoreceptor.

Example 16 In Example 15, a photoreceptor was prepared in which a polyamide layer was formed as an intermediate layer on the photosensitive layer 2. Table 1 shows the evaluation results of this electrophotographic photoreceptor.

Example 17 In Example 15, the antioxidant in the protective layer was pentaerythrityl-tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propione-, which is also a compound having a dialkylhydroxylphenyl skeleton. G) (melting point 117-125
℃), resin was coated with Epicoat # 815 and Epomate B00.
An electrophotographic photoconductor was prepared in the same manner as in Example 2, except that the epoxy resin was made of 2 (both made by Yuka Shell, and dip-coated in a 6 wt% toluene solution with a 2: 1 formulation). Table 1 shows the evaluation results of this electrophotographic photoreceptor.

Example 18. In Example 16, the antioxidant in the protective layer was 1,6-hexanediol-bis (3- (3,5-di-t-butyl-4-hydroxy), which is also a compound having a dialkylhydroxylphenyl group skeleton. Phenyl) propionate) 1 wt% (solid content)
To produce a photoconductor in which Table 1 shows the evaluation results of this electrophotographic photoreceptor.

Example 19 In this example, an ozone decomposable compound was added to the protective layer 24 instead of the antioxidant of Example 15. That is, X-type metal-free phthalocyanine 15 g, polyester resin 27.9 g, butylated melamine resin 6.
A mixture of 98 g, 130 g of toluene and 130 g of MEK was dispersed with a paint shaker (manufactured by Asada Tekko Co., Ltd.) to prepare a photosensitive solution. The photosensitive liquid was applied to the photosensitive substrate 1 by a dipping method and heat-cured at 150 ° C. for 4 hours to form a photosensitive layer. At this time, the film thickness of the photosensitive layer is 18 to 22 μ.
m. On top of that, as a protective layer, β-carotene (an ozonolytic compound) that is an active oxygen quencher
0.01 wt%, a polyester resin 4.8 wt%, and a butylated melamine resin 1.2 wt% were mixed in a toluene solution and heat-cured to obtain a photoconductor test piece. Table 1 shows the evaluation results of this electrophotographic photoreceptor.

Example 20. FIG. 5 is an explanatory diagram showing a photoconductor according to Example 20 of the present invention, in which the surface of the photosensitive layer 2 is treated with a hydrophobic treatment agent.

Next, this embodiment will be described more specifically. The same photoreceptor substrate 1 as in Example 1 was used.
X-type metal-free phthalocyanine 15g, polyester resin 2
A mixed solvent of 130 g of toluene and 130 g of MEK (methyl ethyl ketone) was added to 7.9 g and 6.98 g of butylated melamine resin, and the mixture was dispersed for 2 hours with a paint shaker to prepare a photosensitive solution. This photosensitive solution is dip-coated on the photoreceptor substrate 1 (polyamide layer on aluminum plate), dried at room temperature,
It was dried and cured at 150 ° C. for 1 hour. 0.2 on this photosensitive layer
Fluorine epoxy (E-3630 / 3- (perfluoro-5-methylhexyl) -1,2-epoxypropane manufactured by Daikin), which is a wt% fluorine-based compound, was applied and applied.
It was dried and cured at 4 ° C. for 4 hours to obtain a photoconductor test piece.
The photosensitive liquid was applied so that the thickness of the photosensitive layer at this time was 18 to 22 μm. Table 1 shows the evaluation results of this electrophotographic photoreceptor.
Shown in.

As comparative examples of Examples 1 to 4 and 6 to 14, the characteristics of the untreated photoreceptors of silane coupling and titanate coupling were evaluated. That is, a photosensitive resin substrate 1 was prepared by dipping and coating a polyamide resin layer having an average film thickness of 0.5 μm as an undercoat layer on a polished aluminum plate in a solution consisting of a methanol solution and drying it. X-type metal-free phthalocyanine 15 g, polyester resin 27.9 g, butylated melamine resin 6.98
130 g of toluene, MEK (methyl ethyl ketone)
130 g of the mixed solvent was added and dispersed for 2 hours with a paint shaker to prepare a photosensitive solution. The photosensitive solution thus obtained is dip-coated on the photoreceptor substrate 1 (polyamide layer on an aluminum plate), dried at room temperature and dried and cured at 150 ° C. for 4 hours, and further 30 wt% polyester resin, butylated melamine. It was applied by dip coating in a toluene solution of a resin (blended to 4: 1) and dried and cured at 150 ° C. for 4 hours to obtain a test piece for a photoreceptor. At this time, the photosensitive solution was applied so that the film thickness of the photosensitive layer was 18 to 22 μm. The evaluation results of this electrophotographic photoreceptor are shown in Table 1 as Comparative Example 1.

As a comparative example of Examples 5 and 16, the following photoreceptors having an intermediate layer were evaluated for characteristics. As the photoconductor substrate 1, the same one as in Comparative Example 1 was used. X-type metal-free phthalocyanine 15g, polyester resin 27.9
g, butylated melamine resin 6.98 g with toluene 130
g, and 130 g of MEK (methyl ethyl ketone) were mixed and dispersed by a paint shaker for 2 hours to prepare a photosensitive solution. The photosensitive solution thus obtained is used as the photosensitive substrate 1
A photosensitive layer was formed by dip coating on the above (polyamide layer on aluminum plate), drying at room temperature, and drying and curing at 150 ° C. for 4 hours. Next, dip coating in a 1.0 wt% polyamide / methanol solution and drying at 100 ° C. for 30 minutes to form an intermediate layer,
Further, dip-coat with a 30 wt% polyester resin, butylated melamine resin (blended to 4: 1) / toluene solution, and apply 1
It was dried and cured at 50 ° C. for 4 hours to obtain a test piece for a photoreceptor. At this time, the photosensitive solution was applied so that the film thickness of the photosensitive layer was 18 to 22 μm. The evaluation results of this electrophotographic photoreceptor are shown in Table 1 as Comparative Example 2.

Further, as a comparison with the above Example 17, the characteristic evaluation of the following photoreceptor was carried out. As the photoconductor substrate 1, the same one as in Comparative Example 1 was used. Additive (antioxidant) [pentaerythrityl-tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate) in the protective layer in Example 17 (melting point 117-125 ° C) )]
A photoconductor test piece containing no added was produced. Epicoat # 815 and Epomate B002 (both made by Yuka Shell,
A photoconductor of an epoxy resin composed of a 6 wt% toluene solution with a 2: 1 composition was prepared. The evaluation results of this electrophotographic photoreceptor are shown in Table 1 as Comparative Example 3.

[0053]

[Table 1]

From these results shown in Table 1, it is confirmed that the photoconductor of the present invention is excellent in corona resistance as compared with the photoconductor of the comparative example, and has good characteristics in that dark decay and deterioration of photosensitivity do not occur. did it.

The phthalocyanine photoconductive compound in the present invention is, for example, the above-mentioned JP-B-49-43.
What is shown in the publicly known sample such as Japanese Patent No. 38 is used. Among the phthalocyanine-based photoconductive compounds, it is preferable to use the X-type crystal of the metal-free phthalocyanine used in each of the above examples. In the metal phthalocyanine, phthalocyanine is ideally coordinated with the metal to maintain electrical neutrality, but in reality, a defective portion is likely to occur and that portion is easily oxidized by ozone. On the other hand, metal-free phthalocyanine has only small hydrogen atoms coordinated thereto, and coordination defects are less likely to occur. Further, in terms of high sensitivity, titanyl phthalocyanine is preferably used.

The particle size of the phthalocyanine photoconductive compound is, of course, preferably small so that the particles can be dispersed well and the average particle size is 0.5 μm or less.

In the positive charging type photoreceptor of the present invention, the phthalocyanine compound is usually used in a state of being dispersed in a resin binder. The binder resin used in the present invention has a usual charge retention rate. Is good,
Those having characteristics such as a good dispersion medium of phthalocyanine can be used as they are, but from the viewpoint of ozone resistance, there are few ionic and radical active species, and at the time of the reactive monomer or oligomer treatment described later. Those that do not dissolve or swell are preferred. For example,
Acrylic resins, polyester resins, urethane resins, butyral resins, and thermosetting / photocurable resins such as amino resins and isocyanate resins are preferably used.

The blending ratio of the phthalocyanine photoconductive compound in the photoconductor of the present invention must be 15 to 40%. This is a condition necessary for the photoconductor to function as a positive charging type photoconductor, and when it is less than this range, the photosensitivity is remarkably reduced, and when it is more than this range, it is a bulk of the photoconductor. The resistance is lowered and the charge retention ability is lowered. The most preferable range is 25 to 35% in terms of the balance between photosensitivity and charge retention ability.

Further, the thickness of the photosensitive layer must be in the range of 10 to 30 μm. If it is thinner than this, the charge retention ability is lowered and pinholes are apt to occur, resulting in mechanical characteristics such as resistance to resistance. The printability is significantly reduced. On the other hand, if the thickness is thicker than this range, the photoresponse speed will be insufficient, and the amount of expensive photoconductive material used will increase, which is uneconomical. Considering the charge retention ability, the photoresponse speed, etc., the most preferable range of the film thickness is 15 to 25 μm.

For the photosensitive layer having the above-mentioned film thickness, a phthalocyanine-based photoconductive compound is usually mixed with a resin binder and a solvent and dispersed by a paint shaker as described in each of the above-mentioned examples, or by using a ball mill, a disperser or the like. It may be dispersed, and is formed by applying it to the surface of an aluminum drum or the like provided with an undercoat layer by a dipping method (dipping method), a spray method or the like.

The method of treating the particle surface of the phthalocyanine-based photoconductive compound with a silane coupling agent or a titanate coupling agent (Examples 1 to 3 and 6) was carried out by adding 0.01 to 2. It is advisable to dilute with a suitable solvent so as to have a concentration of about 0% (compounding ratio per solid content when the photosensitive layer is formed), and mix the phthalocyanine photoconductive compound therein and stir sufficiently. If the concentration of the treatment agent is less than this range, sufficient corona resistance cannot be obtained, and if it is more than this range, the photoresponsiveness is deteriorated.

[0062] In addition, the antioxidants and ozone decomposable compound used in Example 8-19, ozone, and active species such as NO _X absorbed efficiently to effectively prevent the deterioration of the photosensitive layer, of The amount added to the photosensitive layer and the protective layer has an optimum value range (both 0.01 to 5.0 wt% / per solid content). Within this range, the characteristics of the photosensitive member are not impaired and deterioration of the photosensitive member is prevented. It can be effectively prevented. When these are too small, their functions become insufficient, and when they are too large, responsiveness deteriorates.

Further, as the antioxidant that can be used in the present invention, in addition to those used in Examples 15, 17 and 18, triethylene glycol-bis (3- (3-t- Butyl-5-methyl-4-hydroxyphenyl) propionate), 2,4-bis-
(N-octylthio) -6- (4-hydroxy-3,5
-Di-t-butylanilino) -1,3,5-triazine, 2,2-thio-diethylenebis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5-di-t-butyl-
4-hydroxyphenyl) propionate, N, N'-
Hexamethylene bis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, tris- (3 , 5-di-t-butyl-
4-hydroxybenzyl) -isocyanurate, 2,4
It may be a compound containing a dialkylhydroxylphenyl skeleton such as -bis ((octylthio) methyl) -O-cresol, or an antioxidant other than these compounds. Further, these antioxidants are added to the protective layer in an amount of 0.01 to
The effect is recognized by adding 5.0 wt%, and a plurality of compounds may be mixed and used.

Since the photosensitive member undergoes mechanical friction during the developing, transferring and cleaning steps, its surface is made of an amino resin such as acrylic resin, polyester resin, urethane resin, butyral resin, silicone resin or epoxy resin. A thermosetting / photocurable resin cured with an isocyanate resin or the like is preferable.

As the conductive support, a conductor or an insulator subjected to a conductive treatment is used. Examples of such a substance include Al, Ni, Fe, Cu and A.
A on metal such as u, or alloy, polyester, polycarbonate, polyimide, glass or other insulating substrate
Illustrative examples include a thin film formed of a metal such as 1, Ag, Au or the like or a conductive material such as In ₂ O ₂ , SnO ₂ or the like, and a paper subjected to a conductive treatment. The shape of the conductive support is not particularly limited, and a drum shape, a plate shape, or a belt shape may be used if necessary.

Further, in the photoreceptor of the present invention, an undercoat layer or an intermediate layer can be used, and its function is to function as a barrier for stabilizing the electrical characteristics and to improve the mechanical characteristics by adhesion. It is known that sex can be improved.

[0067]

As described above, according to the present invention, a phthalocyanine photoconductive compound having a particle surface treated with a coupling agent is dispersed in a binder resin to form a photosensitive layer. It was possible to improve the corona resistance without deteriorating the photosensitivity characteristics.

The corona resistance could also be improved by treating the surface of the photosensitive layer with a coupling agent.

Further, by adding an antioxidant or an ozone decomposable compound into the photosensitive layer, the corona resistance could be improved.

As the above coupling agent, a silane type or titanate type coupling agent is effective.

The same effect can be obtained by subjecting the surface of the photosensitive layer to a hydrophobic treatment.

Fluorine compounds are effective as the hydrophobic treatment agent.

The corona resistance could also be improved by providing a protective layer containing an antioxidant or an ozone decomposable compound on the photosensitive layer.

Further, as an ozone decomposable compound to be added to the photosensitive layer or the protective layer, one using an active oxygen quencher is effective.

The phthalocyanine photoconductive compound is a metal-free phthalocyanine X-type crystal having an average particle size of 0.5 μm or less, dispersed in a binder resin in an amount of 15 to 40% by weight, and a photosensitive layer having a thickness of 10 to 10. By making it 30 μm,
It has excellent ozone resistance, photosensitivity, charge retention ability, printing durability, and photoresponse speed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a photoconductor according to Examples 1 to 3 and 6 of the present invention.

FIG. 2 is an explanatory diagram showing a photoconductor according to Examples 4 and 7 of the present invention.

FIG. 3 is an explanatory diagram showing a photoconductor according to Examples 8 and 9 of the present invention.

FIG. 4 is an explanatory diagram showing a photoconductor according to Examples 15, 17 and 18 of the present invention.

FIG. 5 is an explanatory diagram showing a photoconductor according to Example 20 of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate 2 Photosensitive layer 20 Coupling-treated phthalocyanine-based photoconductive compound 21 Binder resin 22 Phthalocyanine-based photoconductive compound 23 Antioxidant 24 Protective layer

Front Page Continuation (72) Inventor Wei Nagae 8-1-1 Tsukaguchihonmachi, Amagasaki City Mitsubishi Electric Corporation Material Device Research Center (72) Inventor Kajuko Wakita 8-1-1 Tsukaguchihonmachi, Amagasaki Mitsubishi Electric Corporation (72) Inventor Yoshimi Sugimoto, 8-1-1 Tsukaguchihonmachi, Amagasaki Mitsubishi Electric Corporation

Claims (9)

[Claims] 1. A positive charging type electrophotographic photoreceptor comprising a photosensitive layer having a phthalocyanine photoconductive compound dispersed in a binder resin, wherein the phthalocyanine photoconductive compound dispersed in the binder resin is a particle thereof. A positively chargeable electrophotographic photoreceptor, the surface of which is treated with a coupling agent. 2. A positive charging type electrophotographic photosensitive member comprising a photosensitive layer in which a phthalocyanine photoconductive compound is dispersed in a binder resin, wherein the surface of the photosensitive layer is treated with a coupling agent. Positively charged type electrophotographic photoconductor. 3. The positive charging type electrophotographic photoconductor according to claim 1, wherein an antioxidant or an ozone decomposing compound is added in the photosensitive layer. . 4. A positive charging type electrophotographic photoconductor, wherein the coupling agent according to any one of claims 1 to 3 is a silane type or titanate type coupling agent. 5. A positive charging type electrophotographic photosensitive member comprising a photosensitive layer in which a phthalocyanine photoconductive compound is dispersed in a binder resin, wherein the surface of the photosensitive layer is subjected to a hydrophobic treatment. Charge type electrophotographic photoreceptor. 6. The positive charging type electrophotographic photosensitive member according to claim 5, wherein the hydrophobizing agent is a fluorine compound. 7. A positive charging type electrophotographic photoreceptor comprising a photosensitive layer in which a phthalocyanine photoconductive compound is dispersed in a binder resin, wherein a protective layer containing an antioxidant or an ozone decomposable compound is formed on the photosensitive layer. A positive charging type electrophotographic photoconductor characterized by being provided. 8. A positive charging type electrophotographic photoreceptor, wherein the ozone decomposing compound according to claim 3 or 7 is an active oxygen quencher. 9. The phthalocyanine photoconductive compound according to claim 1, which is an X-type crystal of a metal-free phthalocyanine having an average particle size of 0.5 μm or less, and is contained in a binder resin in an amount of 15 to 40% by weight. Dispersed, photosensitive layer thickness is 1
Positively charging type electrophotographic photoconductor characterized by having a thickness of 0 to 30 μm.