JP2000321797A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the amount of film chipping and to eliminate the problem of filming of toners by incorporating an organic binder resin of a high molecular weight and a lubricant into a charge transfer layer. SOLUTION: This electrophotographic photoreceptor includes the photoreceptor formed by laminating an underlying layer, a charge generating layer and the charge transfer layer containing the organic binder resin of the high molecular weight and the lubricant on a conductive substrate, the photoreceptor formed by laminating the charge generating layer, the charge transfer layer, then an over-coating layer containing the organic binder resin of the high molecular weight and the lubricant on the conductive substrate and the photoreceptor formed by laminating a single photosensitive layer containing the organic binder resin of the high molecular weight and the lubricant on the conductive substrate. A compound of a methyl phenyl silicon system is used for the lubricant, a diamine-base compound, styryl-base compound or their mixture is used for the charge transfer material and an azo-base compound or phthalocyanine-base compound is used for the charge transfer material. The charge transfer layer consists of the diamine-base compound and the organic binder resin of the high molecular weight and the lubricant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member for a copying machine or a laser printer, and more particularly to an electrophotographic photosensitive member having good printing durability.

[0002]

2. Description of the Related Art The technology of electrophotography has been developed in the field of copiers, and has recently been applied to laser printers to achieve high image quality, high speed, and quietness comparable to conventional impact printers. Proud and rapidly spreading.

[0003] The electrophotographic photosensitive member applied to the electrophotographic apparatus is changing from conventional Se or a-Si to an organic photosensitive member. Organic electrophotographic photoreceptors make use of the advantages of non-pollution, film-forming properties, and light weight. By using a substance most suitable for the photoreceptor, the sensitivity can be greatly improved, and the spectral sensitivity can be set according to a desired wavelength of the exposure light.

FIG. 1 is a sectional view showing a conventional electrophotographic photosensitive member. Most of the laminated organic electrophotographic photoreceptors currently in practical use have an undercoat layer 2, a charge generation layer 3, and a charge transport layer 4 laminated on a conductive substrate 1 in this order.
Here, the charge generation layer 3 and the charge transport layer 4 constitute the photosensitive layer 6. In such a photoreceptor, a charge generation material is dispersed and dissolved in a solvent together with an organic binder resin, and a coating solution is applied and dried to form a charge generation layer 3. Subsequently, a charge transport material is further added to the organic binder resin. A charge transport layer 4 is formed by applying and drying a coating solution dissolved in a solvent.

[0005]

However, such an organic electrophotographic photoreceptor has a problem in that the printing durability is poor as compared with a conventional electrophotographic photoreceptor made of Se or a-Si. In order to improve printing durability, a method of increasing the molecular weight of the organic binder resin added to the charge transport layer is used.
When the molecular weight of the organic binder resin is increased, the amount of film scraping of the charge transport layer decreases, but the amount of toner filming increases, so the amount of pressure applied to the blade must be increased. There is a problem that the shaving amount is increased and the printing durability is not finally improved.

An object of the present invention is to provide an electrophotographic photoreceptor having good printing durability by preventing the occurrence of toner filming when the molecular weight of an organic binder resin is increased. It is in.

[0007]

According to the present invention, there is provided an electrophotographic apparatus comprising a conductive substrate and a charge generating layer formed by laminating a charge transporting material with an organic binder resin. In the photoreceptor, it is achieved by including a high molecular weight organic binder resin and a lubricant in the charge transport layer.

In the above invention, the molecular weight of the organic binder resin is 38,000 or more, and the content of the organic binder resin in the charge transport layer is 40% by weight or more;
Alternatively, it is effective that the content of the lubricant in the charge transport layer is 0.5% by weight or more.

The molecular weight of the organic binder resin is 38,000
If the polymer is the above and the content of the organic binder resin is 40% by weight or more, the amount of film shaving decreases. Even when the charge transport layer contains a high molecular weight organic binder resin, filming of the toner is prevented if the lubricant is present in an amount of 0.5% by weight or more.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As an electrophotographic photoreceptor, a photoreceptor in which an undercoat layer, a charge generation layer, and a charge transport layer containing a high molecular weight organic binder resin and a lubricant are laminated on a conductive substrate, Photoreceptor having a charge generation layer, a charge transport layer, and then an overcoat layer containing a high molecular weight organic binder resin and a lubricant on a substrate, and a high molecular weight organic binder resin and a lubricant on a conductive substrate. A photoconductor in which a single photosensitive layer is laminated is included.

As the lubricant, a methylphenylsilicon compound or a dimethylsilicon compound is used. As the charge transporting substance, a diamine compound, a styryl compound or a mixture thereof is used. As the charge generating substance, an azo compound or a phthalocyanine compound is used. EXAMPLE A nylon-based subbing layer was applied to a thickness of 3 μm on a cylindrical aluminum conductive substrate, and a charge-generating layer containing an azo compound represented by the chemical formula 1 was applied to a thickness of 0.5 μm. Applied. A charge transport layer was applied over the charge generation layer.
The charge transport layer is composed of a diamine compound represented by Formula 2, an organic binder resin having a high molecular weight, and a lubricant.
Is the thickness. A charge transport layer was formed using an organic binder resin having a molecular weight of 38,000 or 48,000, a lubricant, and the above-described diamine-based compound, and changing the charge transport material / binder ratio and the amount of the lubricant added, respectively. Thus, seven types of photoconductors were produced.

[0012]

Embedded image

[0013]

Embedded image Each of the obtained photoreceptors was mounted on a copier and copied 300,000 times, and the amount of film scraping of the charge transport layer was measured after 100,000 and 300,000 times. Further, filming was judged from the copied image after 100,000 times. The results are shown in Table 1. In the table, ○ indicates a significant effect, Δ indicates an effect, ×
Indicates no effect.

[0014]

[Table 1] As shown by the characteristics of the photoreceptors of Examples 1 to 7, the charge transport material / binder ratio was 5: 5 and the lubricant concentration was 0.5.
At 2% by weight, filming occurs, but there is no practical problem. When the lubricant concentration is 0.5% by weight or more, filming does not occur, and the film abrasion amount is about 3 even after 100,000 copies.
The target of 10 μm or less was achieved after 300,000 copies of μm, and a photosensitive member optimal for a high-speed copying machine was obtained. Comparative Example A nylon-based subbing layer was applied to a thickness of 3 μm on a cylindrical aluminum conductive substrate, and a charge generation layer containing an azo-based compound was applied to a thickness of 0.5 μm. A charge transport layer was applied over the charge generation layer. The charge transport layer is made of a diamine compound represented by Formula 2, an organic binder resin having a high molecular weight, and a lubricant, and has a thickness of 30 μm. A charge transport layer was formed using an organic binder resin having a molecular weight of 28,000, 38,000 and 48000, a lubricant and the above-mentioned diamine-based compound, and changing the charge transport material / binder ratio. Thus, nine types of photoconductors were produced.

The obtained photoreceptor was mounted on a copying machine and copied 300,000 times, and the amount of film scraping of the charge transport layer was reduced by 1
The measurement was performed at 100,000 times and 300,000 times. Further, filming was judged from the copied image after 100,000 times. The results are shown in Table 2. In the table, x indicates no effect.

[0016]

[Table 2] As shown by the characteristics of Comparative Examples 1 to 9, the molecular weight was 2
When the organic binder resin of 8000 is used, filming does not occur, but the amount of film shaving is large. In this case, it becomes 10 μm or more after 300,000 times of copying, and it is not possible to satisfy the requirement of the film shaving amount of 10 μm or less.

When an organic binder resin having a molecular weight of 38,000 or more is used, the amount of film shaving is small, but filming is observed except when the charge transporting material / binder ratio is 4: 6. When the charge transport material / binder ratio is 4: 6, the amount of film shaving becomes 10 μm or more after 300,000 operations.

[0018]

According to the present invention, in a photoreceptor for electrophotography, comprising a charge generation layer on a conductive substrate and then a charge transport layer in which a charge transport substance is bound with an organic binder resin, the charge transport layer Since it contains a high molecular weight organic binder resin and a lubricant, it is possible to obtain an electrophotographic photoreceptor having a small amount of film scraping and having no problem of toner filming.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a conventional electrophotographic photoconductor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive substrate 2 undercoat layer 3 charge generation layer 4 charge transport layer 6 photosensitive layer

Claims (3)

[Claims] 1. An electrophotographic photoreceptor comprising a charge generation layer laminated on a conductive substrate, and then a charge transport layer in which a charge transport substance is bound with an organic binder resin. An electrophotographic photoreceptor comprising an organic binder resin and a lubricant. 2. The organic binder resin having a molecular weight of 3800.
The electrophotographic photoconductor according to claim 1, wherein the content is 0 or more, and the content of the organic binder resin in the charge transport layer is 40% by weight or more. 3. The electrophotographic photoconductor according to claim 1, wherein the content of the lubricant in the charge transport layer is 0.5% by weight or more.