JPH0253070A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body which is harmless to environment and repetition by providing a charge transfer layer contg. a hydrazone compd. onto a charge generating layer contg. tau type nonmetallic phthalocyanine provided on a charge injection control layer. CONSTITUTION:The charge injection control layer is provided on a conductive base by mixing conductive powder and polyamide resin and the charge generating layer contg. the tau type nonmetallic phthalocyanine is provided on the charge injection control layer. Further, the charge transfer layer contg. the hydrazone compd. is provided on the charge generating layer. Namely, the effect similar to the effect of aluminum is obtd. when tin oxide contg. antimony and the polyamide resin are mixed at a suitable ratio. The electrophotographic sensitive body having the high stability to the environment and repetition is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electronic copying machines, printers, and facsimile machines, and particularly relates to an electrophotographic photoreceptor suitable for an electrophotographic printer that uses a laser beam to imagewise line scan the image. be.

2. Description of the Related Art In recent years, the development of electrophotographic printers using laser beams has been remarkable, but the reversal development method has become mainstream from the viewpoint of copying speed and resolution. This method differs from the method previously used in electrostatic copying machines, in that it attaches toner to the exposed areas with a low potential, causing uneven charging, interference fringes, and black spots on the photoreceptor substrate. This resulted in an extremely sensitive understanding of the impact. To solve this problem, the surface may be roughened, an insulating resin may be provided between the conductive substrate and the phosphor layer, or a conductive layer may be created by mixing an i-conductive material and a resin. Efforts have been made. (For example, Japanese Unexamined Patent Publication No. 61-240247) Problems to be Solved by the Invention However, in the method of roughening the surface, the effect appearing on the image differs depending on the degree of roughening. That is, if the degree of interference is weak, moire-like interference fringes will appear on the image, and if it is too strong, image defects will appear. Therefore, it is necessary to control the roughness within a certain range, which poses a practical problem. Furthermore, when the surface is roughened by cutting, periodic scraping causes interference fringes.

When an insulating resin is provided between the conductive substrate and the photosensitive layer, the resin itself is highly dependent on the environment, and in particular, it cannot be expected to be effective in covering defects in the conductive substrate under high temperature and high humidity conditions. This case can be dealt with by using a thick film, but this results in deterioration of characteristics at low temperatures and low humidity. As mentioned above, there were various problems.

Means for Solving the Problems In order to solve the above problems, the present invention provides a charge injection control layer made by mixing a conductive powder and a polyamide resin on a conductive support, and a charge injection control layer formed on the charge injection control layer. The present invention provides an electrophotographic photoreceptor characterized in that a charge generation layer containing a type-free metal phthalocyanine is provided, and a charge transport layer containing a hydrazone compound is provided on the charge generation layer.

As a result of research, the inventors found that the effect of τ-type metal-free phthalocyanine on metals such as gold and copper as a charge generation layer and when it was provided on aluminum, regardless of the charge transport layer laminated. A difference occurred in chargeability. This is because gold, copper, and aluminum have different work functions, and τ
Gold and copper have similar work functions to τ-type metal-free phthalocyanine, and since there is an ohmink contact between the metal and the τ-type metal-free phthalocyanine, allowing charge to move freely, these metals are rarely used as base materials. Not charged. On the other hand, since aluminum forms a Schottky contact with holes with the τ-type metal-free phthalocyanine, the charge movement is limited and the charging property is good. The inventors took a hint from this and searched for a material with a work function close to that of aluminum. As a result, they discovered that when tin oxide containing antimony and polyamide resin are mixed in an appropriate ratio, they have the same effect as aluminum. As a result, we succeeded in obtaining an electrophotographic photoreceptor with excellent environmental and repeated stability by removing the insulating layer mainly made of resin inserted between the base metal and the charge generation layer, which has been widely used to date. did.

EXAMPLE Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

Although any metal can be used as the base material, aluminum was used this time. The charge control layer provided on top of this is made of polyamide (
The weight ratio of antimony-doped tin oxide (T-1, manufactured by Mitsubishi Metals Co., Ltd.) was varied from 20% to 60% in AQ nylon (manufactured by Toshi Co., Ltd.), hardening agent melamine resin (M-3400), and used. These were dispersed in a methanol solvent, applied by dip coating, and dried at 150 degrees. A photosensitive layer is coated on this charge injection control layer. The photosensitive layer is a charge generation layer in which τ-type metal-free phthalocyanine and butyral resin (manufactured by Sekisui Chemical Co., Ltd., trade name Nisrex BH-3) are mixed in a weight ratio of 4:3, and the mixture is prepared using a solvent such as tetrahydrofuran. After dispersing the mixture, a film was formed to a thickness of about 0.3 μm and used.

The charge transport layer was prepared by mixing a hydrazone compound with a polycarbonate resin. As a hydrazone compound, 1-
Phenyl-1,2,3,4-tetrahydroquinoline-6
- Carpoxyaldehyde ~ 1.1'-diphenylhydrazone is mixed in a 1:1 weight ratio with a polycarbonate resin (Mitsubishi Chemical Industries, Ltd., trade name: Tubarex 7030A, currently manufactured by Bayer, Macrophor N), and a solvent such as methylene chloride is added. A film was formed on the charge generation layer. Film thickness is 1
7~20/! It was m. The photosensitive drum thus produced was evaluated using the tester shown in the figure. The figure is a front view of the tester.
1 is a charger, 2 is a photoreceptor, 3 is an exposure light source, and 5 is a static elimination lamp. Further, 7a and 7b are electrometer probes, 7a is installed for the purpose of monitoring the potential after charging, and 7b is installed for the purpose of monitoring the potential after static elimination. Exposure energy is 1.50μJ/c4
, the static elimination energy is 9.75 uJ/c4. The circumferential speed of the drum was 120 mm/sec. Test at 33°C/8
The test was carried out under an environment of 0% PH and 7°C/20% PH. Table 1 shows the weight ratio (P/B) of conductive powder and polyamide resin.
, indicates the thickness and specific resistance of the charge control layer.

Table 1 Table 2 also compares potential fluctuations when a photosensitive layer is provided on this charge control layer between the first time and the 1000th time.

1000 times in Table 2 corresponds to copying 1000 A4 sheets.

Table 2 As is clear from Table 2, when the weight ratio (P/B) of the conductive powder and polyamide resin is 30 wt%, the potential repeat stability is 30°C/80% PH and 7°C/ 20%P
It can be said that it is optimal in both environments. Further, from Table 1, the specific resistance of the charge injection control layer in this case is 4 to 5×10I0Ω·mark. For reference, Table 3 shows the results of 1000 repetitions when a photosensitive layer was laminated in the order of a charge generation layer and a charge transport layer on an aluminum base material.

Through a series of these experiments, it was discovered that a charge injection control layer of 30% by weight of antimony-doped tin oxide and polyamide resin exerts the same effect as aluminum on τ-type metal-free phthalocyanine.

This effect collapses as the proportion of tin oxide to resin increases. That is, this means that the Schottky contact with the τ-type metal-free phthalocyanine is broken and changes to ohmic properties.

Effects of the Invention In short, the present invention provides a charge injection control layer with a specific resistance of 101°Ω·1 by mixing antimony-doped tin oxide and polyamide resin as conductive powder on a conductive support, and A charge generation layer containing τ-type metal-free phthalocyanine is provided on the injection control layer.

This makes it possible to achieve Schottky contact, eliminate the need for an insulating layer intended to prevent charge injection from the conductive base material by the resin, and provide an electrophotographic photoreceptor that is stable in the environment and with repeated use.

No. figure It is.

1... Charger, 2... Photoreceptor, 3...
...Exposure light source, 5...Static elimination lamp, 7a,
7b... Electrometer probe.

Claims (3)

[Claims] (1) A charge injection control layer is formed by mixing a conductive powder and a polyamide resin on a conductive support, and a charge generation layer containing a τ-type metal-free phthalocyanine is provided on the charge injection control layer;
An electrophotographic photoreceptor characterized in that a charge transport layer containing a hydrazone compound is provided on the charge generation layer. (2) Claim (1) wherein the specific resistance of the charge injection control layer made of conductive powder and polyamide resin is 10^1^0 Ωcm.
) The electrophotographic photoreceptor described above. (3) The electrophotographic photoreceptor according to claim (1), wherein the conductive powder is tin oxide containing antimony.