JPH10115942A - Electrophotographic organic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a single layer type electrophotograhic organic photoreceptor usable in a positive charging reduced in the deterioration of potential acceptance in the case of successive repeating uses by doping a phthalocyanine high in ionization potential. SOLUTION: The single photosensitive layer is formed on a conductive substrate 2 and it contains a mixed aggregate of an X type metal-free phthalocyanine and a titanyl phthalocyanine is doped with the phthalocyanine compound higher in the ionization potential than the mixed aggregate, thus permitting transfer of surface potential imediately after charging at the time of image formation to be obstructed by the hardening obtained by ionization potential of the doped phthalocyanine and to be prevented from deterioration of potential acceptance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic photoreceptor for electrophotography, and more particularly to a single-layer type organic photoreceptor for electrophotography in which a photosensitive layer has a single layer and is used by positive charging.

[0002]

2. Description of the Related Art An electrophotographic organic photoreceptor currently in practical use has an undercoat layer (UCL), a charge generation layer (CGL), and a charge transport layer (TCL) formed in this order on a conductive substrate. , And a configuration called a function-separated laminated type, and a type used in a negative charging system is mainly used.
In the photoreceptor having such a configuration, each layer is usually formed by applying a coating solution obtained by dispersing and dissolving a required organic material in an organic solvent. There is a problem that the manufacturing defect rate is large. In addition, since it is used with negative charging, negative corona discharge occurs when the surface of the photoconductor is charged with corona discharge, which is a normal charging method, and more ozone is generated as compared with positive corona discharge. There was a problem that the durability of the body was poor and the adverse effect on the surrounding environment was large. For this,
A photoreceptor which can be used in a single layer type and a positive charging system has been studied. Such a single-layer type photoreceptor generally has a high dielectric constant as a binder, a high polymer having high insulating properties and a good film-forming property, and an organic photoconductive substance mixed with an organic solvent on a conductive substrate. It is produced by applying a dissolved and dispersed coating liquid to form a photosensitive layer.

[0003]

However, in a single-layer type organic photoreceptor for electrophotography, the chargeability gradually decreases after continuous repetition of use, and the density of an image obtained with a regular development type electrophotographic apparatus is reduced. In the electrophotographic apparatus of the reversal developing system, there has been a problem that a blank portion of an image becomes black (ground fog).

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, reduces the charging performance when used continuously and repeatedly, and
An object of the present invention is to provide a single-layer organic photoconductor for electrophotography that can be used for positive charging.

[0005]

According to the present invention, there is provided an electrophotographic organic photoreceptor comprising a single photosensitive layer on a conductive substrate, wherein the photosensitive layer is an X-type metal-free material. By including a mixed agglomerate of phthalocyanine and titanyl phthalocyanine as a charge generating material, and further by using a photoreceptor doped with a phthalocyanine compound having a higher ionization potential than a mixed agglomerate of X-type metal-free phthalocyanine and titanyl phthalocyanine Will be resolved.

[0006] By doping a phthalocyanine compound having a higher ionization potential than a mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine, the transfer of surface charge immediately after charging at the time of image formation causes the ionization potential of the doped phthalocyanine compound. The effect hindered by the above is obtained, and a decrease in charging ability can be reduced.

As a phthalocyanine compound having a higher ionization potential than a mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine, phthalocyaninato nickel 2 and dichlorophthalocyaninato tin 4 are preferred. In this case, a polyester resin is preferably used as a binder for forming the photosensitive layer.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The conductive substrate of a photoreceptor according to the present invention may be in any shape of a cylinder, a plate, a film, or a metal, such as aluminum, stainless steel, nickel, or glass. Any of those usually used as a substrate of a photoreceptor, such as those obtained by conducting a conductive treatment on a resin or the like, can be used.

On such a conductive substrate, a binder,
An appropriate amount of a phthalocyanine compound having a higher ionization potential than a mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine as a charge generating material and a mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine as a doping material, The photoreceptor according to the present invention can be obtained by forming a single photosensitive layer by applying and drying the dispersed and dissolved liquid.

[0010] A mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine (ionization potential 4.
Examples of the phthalocyanine compound having an ionization potential higher than 85 eV) include dichlorophthalocyaninato tin 4 (5.05 eV),
Phthalocyaninato nickel 2 (ionization potential: 6.2 eV).

[0011] Examples of the binder include polyester resin, polyvinyl resin, polycarbonate resin, polystyrene resin, and acrylic resin.

[0012]

Embodiments Hereinafter, specific embodiments will be described. Example 1 Red Devil containing 80 g of a SUS ball containing a mixed solvent of 20 g of cyclohexanone and 20 g of dichloromethyl, 1.59 g of a mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine, and 0.053 g of phthalocyaninato nickel 2 And stirred for 1 hour to obtain a dispersion.
9 g of a polyester resin (manufactured by Toyobo Co., Ltd .; trade name "Vylon 200") was added to the dispersion, and the mixture was further stirred for 1 hour with a red devil to prepare a coating solution. This coating solution was applied on an aluminum alloy plate at 20 μm and dried to prepare a photoreceptor.

Example 2 In Example 1, except that the amount of phthalocyaninato nickel 2 was changed from 0.053 g to 0.53 g,
A photoconductor was produced in the same manner as in Example 1. Example 3 In Example 1, the phthalocyaninato nickel 2 was added in an amount of 0.1%.
053 g of 0.053 of dichlorophthalocyaninato tin
A photoconductor was prepared by the same way as that of Example 1 except that g was changed to g.

Example 4 A photoconductor was prepared by the same way as that of Example 3 except that the addition amount of dichlorophthalocyaninato tin was changed from 0.053 g to 0.53 g. Comparative Example 1 In Example 1, the phthalocyaninato nickel 2 was added in an amount of 0.1%.
A photoconductor was prepared by the same way as that of Example 1 except that 053 g was not added.

COMPARATIVE EXAMPLE 2 In Example 1, the phthalocyaninato nickel 2 was treated with 0.1.
A photoconductor was prepared by the same way as that of Example 1 except that 053 g was changed to 0.053 g of chlorophthalocyaninato aluminum (ionization potential 4.65 eV). Comparative Example 3 A photoconductor was prepared by the same way as that of Comparative Example 2 except that the addition amount of chlorophthalocyaninatoaluminum was changed from 0.053 g to 0.53 g.

The change in the amount of charge of each photoconductor obtained as described above during repeated use is described in "EPA8" manufactured by Kawaguchi Electric Works.
000 ". The corona discharge voltage is set so that the photoconductor surface is charged to + 600V. The surface of the photoreceptor is charged with the discharge voltage, and thereafter, white light of 0.7 lux is irradiated. Such a charging and irradiating process is performed 50 times.
The repetition was performed 0 times, and the first and 500th charge positions were measured, and the change in the charge amount was determined as the difference. Table 1 shows the results.

[0017]

[Table 1] As shown in Table 1, each of the photoconductors of Examples 1, 2, 3, and 4 doped with a phthalocyanine compound having a higher ionization potential than a mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine was doped. The decrease in the charge amount is smaller than that of the photosensitive member of Comparative Example 1 which is not provided. The doping amount may be a very small amount (about 0.5% by weight) as seen in Examples 1 and 3, but as shown in Examples 2 and 4, it is preferable that the doping amount is further increased by about one digit (about 5% by weight). Great effect. However, if the amount is too large, the sensitivity tends to decrease, which is not preferable.

Further, as seen in the photoreceptors of Comparative Examples 2 and 3, the photoreceptor doped with a phthalocyanine compound having a smaller ionization potential than the mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine has a lower charge amount. The drop is greater. The effect of doping a phthalocyanine compound having a higher ionization potential than a mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine is apparent.

[0019]

According to the present invention, in an organic electrophotographic photoreceptor comprising a single photosensitive layer on a conductive substrate,
The photosensitive layer contains a mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine as a charge generating material, and is further doped with a phthalocyanine compound having a higher ionization potential than a mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine. Photoreceptor. By doping the phthalocyanine compound having a large ionization potential as described above, a single-layer type electrophotographic organic photoreceptor that can be used for positive charging with reduced charging ability reduction during continuous repeated use can be obtained.

Claims (4)

[Claims] 1. An electrophotographic organic photoreceptor comprising a single-layer photosensitive layer on a conductive substrate, wherein the photosensitive layer contains a mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine as a charge generating material. An organic photoreceptor for electrophotography, further comprising a phthalocyanine compound having a higher ionization potential than a mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine. 2. The organic photoconductor for electrophotography according to claim 1, wherein the phthalocyanine compound having a higher ionization potential than a mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine is phthalocyaninato nickel 2. . 3. The organic photosensitive material for electrophotography according to claim 1, wherein the phthalocyanine compound having a higher ionization potential than the mixed aggregate of X-type metal-free phthalocyanine and titanyl phthalocyanine is dichlorophthalocyaninato tin 4. body. 4. The organic photoconductor for electrophotography according to claim 2, wherein the binder used for the photosensitive layer is a polyester resin.