JPS6391667A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body which is used in a simultaneous method and which exhibits high developing efficiency and forms a high-contrast image by incorporating titanium oxide particles into the surface layer thereof. CONSTITUTION:The titanium oxide (TiO2) particles are incorporated into the surface layer 5 of the electrophotographic sensitive body formed by laminating a carrier generating layer 3, a carrier transfer layer 4, and the surface layer 5 on a transparent conductive substrate layer 2. The light transmitted through the carrier generating layer 3 is transmitted through the carrier transfer layer 4, reflects on the surface layer 5 contg. the TiO2 particles, and arrives at the carrier generating layer 3 by passing the carrier transfer layer 4 again. The light eventually contributes to the generation of electric charge again when the light passes the carrier generating layer 3 in the direction of the substrate layer 2. The light at the time of exposing can thus be effectively utilized. The surface layer 5 contg. the TiO2 particles is preferably the layer which does not contain a conductive material, has high resistance and is smaller in film thickness than the carrier generating layer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more specifically, it uses a photoreceptor comprising a laminate of a transparent conductive base layer, a carrier generation layer, a carrier transfer layer, and a surface layer. , an electronic method using a developing method in which a toner image corresponding to the exposed image is formed by exposing the photoreceptor to a photoimage from the base layer side and simultaneously applying toner to the surface of the photoreceptor at the photoexposed area. This invention relates to improvements in electrophotographic photoreceptors used in photographic processes.

[Conventional technology]

Currently, the Carlson process is the mainstream electrophotographic process, but recently, a method of forming images by simultaneously performing exposure and development (hereinafter referred to as the simultaneous method) has the potential to greatly simplify the process. ) has been studied and proposed in, for example, Japanese Patent Laid-Open No. 58-153957.

In this method, a photoreceptor in which a photoconductive layer is laminated on a transparent conductive substrate layer is used.The photoreceptor is exposed to light from the substrate layer side, and at the same time as the exposure, a bias voltage is applied to the surface of the photoreceptor in the exposed area. At this time, a bias voltage is applied to the toner in contact with the photoreceptor surface in the unexposed area where the photoconductive layer acts as an insulator and the exposed area where it acts as a conductor. There is a difference in the amount of charge injected due to the difference in the amount of charge, and the difference in the amount of charge becomes a difference in the electrostatic adhesion force to the surface of the photoreceptor, making development possible.

The electrophotographic photoreceptor used in this simultaneous method generally has a photoconductive layer laminated on a transparent conductive substrate layer, similar to photoreceptors used in other electrophotographic processes, such as the Carlson process. ◇ Various structures and various photoconductive materials have been developed as photoconductive layers of such conventional photoconductors, but among them The photoconductive layer is made of a material that contains a substance that absorbs light and generates electric charges, for reasons such as the wide selection of materials used to manufacture the photoreceptor and the ability to improve the mechanical properties required for the electrophotographic process. It has been proposed to have a structure in which the functions are separated into a carrier generation layer and a carrier transfer layer that transports either holes or electrons or both of the generated charges, and these layers are stacked.

[Problem that the invention seeks to solve]

However, the conventional electrophotographic photoreceptor has a structure in which the photoconductive layer is laminated on a transparent conductive base layer.
When applied to the simultaneous method, there is a problem that the development efficiency is low. The reason for this is: - In electrophotographic processes other than simultaneous, exposure is performed by light irradiation from the surface side of the photoreceptor, and the conductive base layer is made of a material with high light reflectance such as an aluminum tube or an aluminum vapor-deposited layer. In this method, the incident light is reflected back to the photoconductive layer by the conductive substrate layer and is used again to generate charges, which is effectively used. However, in the simultaneous method, the exposure is from the substrate layer side. One of the reasons is that the incident light only contributes to the generation of charges when it passes through the carrier generation layer because it is performed by light irradiation, and the light cannot effectively contribute to the generation of charges. This is thought to cause a significant drop in development efficiency, especially since the quantum efficiency of currently used carrier-generating substances is extremely low. The purpose of the present invention is to develop an excellent electron [Means for solving the problems] The electrophotographic photoreceptor of the present invention has a carrier generation layer, a carrier transfer layer, and a titanium oxide surface layer on a transparent conductive base layer. (
T102) is characterized by containing particles.

[For production]

Since the quantum efficiency of the carrier-generating substance is low, the light incident from the base layer side only contributes slightly to charge generation when passing through the carrier-generating layer. Therefore, the light that has passed through the carrier-generating layer It has enough energy to generate electric charge.

According to the electrophotographic photoreceptor of the present invention, the light that has passed through the carrier generation layer further passes through the carrier transfer layer, and TlO
The light is reflected by the surface layer containing the two particles, passes through the carrier movement layer again, reaches the carrier generation layer, and when transmitted through the carrier generation layer toward the base layer, contributes to the generation of charges again, and is exposed to light. It is preferable that the surface layer containing particles does not contain a conductive substance, has high resistance, and has a thickness smaller than that of the carrier generation layer. Embodiment] FIG. 1 is a cross-sectional view of an electrophotographic photoreceptor in an embodiment of the present invention, in which 1 is a substrate, 2 is a transparent conductive base layer, 3 is a carrier generation layer, 4 is a carrier migration layer, and 5 is a This is the surface layer.

In the following examples, an electrophotographic photoreceptor with this structure was created,
We conducted an evaluation.

FIG. 2 shows how development is performed by the simultaneous method using the electrophotographic photoreceptor of the present invention.

An electrophotographic photoreceptor 6 formed by laminating a substrate 1, a transparent conductive substrate layer 2, a carrier generation layer 3, a carrier movement layer 4, and a surface layer 5 receives image exposure 8 as it moves in the direction of an arrow 7.

Due to the magnetic nature of the toner 9, the toner 9 is brought into contact with the photoreceptor 6 in the exposed area by a well-known magnetic brush formed using a magnetic roller 10 and a sleeve 11.

Since a bias voltage 12 is applied to the sleeve 11, charge is injected into the toner 9 that is in contact with the photoreceptor 6, but the amount of injection is different between the exposed area and the unexposed area, and as a result, the amount of charge is injected into the toner 9 that is in contact with the photoreceptor 6. A difference is caused in the electrostatic adhesion force of the toner 9 to the 60 surface, and development is performed. [Example 1] A transparent conductive film (
Using the product name (:!ELKK-KEO, manufactured by Daicel Chemical Industries, Ltd.), type-free metal 7-tet-tetracyanine (
Product name IF astofta* Blue 8110,
manufactured by Dainippon Ink) and polyvinyl acetate (product name: Denka A)
SR, manufactured by Denki Kagaku Kogyo ■) at a weight ratio of 3:1,
A solution dispersed in methyl ethyl ketone (hereinafter referred to as MEK) was applied with a doctor blade, dried with hot air, and the surface was uniformly rubbed to form a carrier generation layer.

On this carrier generation layer, a diphenylhydrazone derivative (trade name CTC-236, manufactured by Anan Kogyo Sangyo ■) and polyvinyl butyral (trade name 5-LKC!BM-2, manufactured by Sekisui Chemical Co., Ltd.) were added in a 1:1 weight ratio. A solution dissolved in tetrahydro-7 run (hereinafter referred to as THF) was applied with a doctor blade, and after drying with hot air, the surface was uniformly scraped to form a carrier transfer layer.

Furthermore, T10. Particles and alkyd-modified silicone (trade name KR-201, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed at a weight ratio of 6=1 and dispersed in xylene. A solution was applied with a doctor blade, and after drying with hot air,
The surface was uniformly rubbed to form a surface layer.

When the electrophotographic photoreceptor produced in this way was mounted on a testing device having a mechanism as shown in Figure 2, a clear and sharp image of the mount was formed on the surface of the photoreceptor. optical density (0ptia&l
Density, hereinafter referred to as 0°D value. )teeth,
It was tOS.

Further, when printing was performed in the same manner using an electrophotographic photoreceptor prepared in the same manner as in this example except that the surface layer did not contain TiO□ particles, the obtained image was 0. The D value was α84.Furthermore, when an electrophotographic photoreceptor was prepared in the same manner as in this example except that it did not have a surface layer, printing was performed in the same manner.
The O and D values of the obtained image were 0.32〇 [Example 2] On the same transparent conductive film as in Example 1, type B steel 7 talocyanine (trade name B-7 Taloshi Ryonin Pure, Sumitomo) manufactured by Kagaku Kogyo ■) and polyvinyl butyral (product name 5-LBO)
EM-2 (manufactured by Tansui Kagaku Kogyo ■) were mixed at a weight ratio of 3=1, and the solution dispersed in THIF was applied with a wire bar.
This was dried with hot air and the surface was scraped uniformly to form a carrier generation layer.

On this carrier generation layer, 1-phenyl-6(4-N
, N-diethylminostyryl)-5-(4-N,N
-diethylaminophenyl) pyrazoline and phenoxy resin (trade name 5TX-07, manufactured by Tobu Kasei Co., Ltd.) were mixed at a weight ratio of 1:1, the solution dissolved in THF was applied using an applicator, and this was dried with hot air to coat the surface. A carrier movement layer was formed by uniformly scraping.

Furthermore, TlO2 particles and polycarbonate (product name N0VARICX, manufactured by Mitsubishi Chemical Corporation) are placed on the carrier transport layer.
were mixed at a weight ratio of 5:1, a solution dispersed in THF was applied with a wire bar, and after drying with hot air, the surface was scraped uniformly to form a surface layer.◎ In this way, When the produced electrophotographic photoreceptor was mounted on the same apparatus as in Example 1 and printed, a sharp image with clear contrast was formed, and the Q and D values of the obtained image were 1.01. In addition, as in Example 1, an electrophotographic photoreceptor was prepared in the same manner as in this example, except that the surface layer did not contain Tie and particles, and an electrophotographic photoreceptor was prepared in the same manner as in this example, except that it did not have a surface layer. When printing was carried out in the same manner using electrophotographic photoreceptors prepared in the same manner, the O and D values of the image obtained with the former were 075, and the O and D values of the image obtained with the latter were α28.

[Example 3] On the same transparent conductive film as in Example 1, copper 7 talocyanine (trade name OM-Os 05, manufactured by Wako H Pharmaceutical Industries Ltd.) finely ground using a ball mill and polyester (trade name Byron 200 (manufactured by Toyobo) was mixed at a weight ratio of 3=1, the solution dispersed in MIK was applied with a doctor blade, and after drying with hot air, the surface was uniformly rubbed to form a carrier generation layer. 〇 On this carrier generation layer, 1=1 diphenylhydrazone derivative (trade name CTC!-256, manufactured by Anan Kogyo Sangyo ■) and a phenoxy resin (trade name 5TX-07, manufactured by Tobu Kasei) were applied.
A solution dissolved in MIK was applied with a doctor blade, and after drying with hot air, the surface was scraped uniformly to form a carrier migration layer.Furthermore, on the carrier migration layer , Tie, particles and styrene-methyl methacrylate copolymer (trade name: Estyrene M
! J-200, manufactured by Nippon Steel Chemical Industry ■) at a weight ratio of 6:1, the solution dispersed in MIK was applied with a doctor blade, and after drying with hot air, the surface was scraped uniformly. When the electrophotographic photoreceptor thus prepared was placed in the same apparatus as in Example 1 and printed, a sharp image with clear contrast was formed. The O and D values of O were 103. Also, as in Example 1, an electrophotographic photoreceptor was prepared in the same manner as in this example except that the surface layer did not contain TiO and particles, and When printing was carried out in the same manner using electrophotographic photoreceptors prepared in the same manner as in this example except that the surface layer was not provided, the images obtained with the former were 0. Ill value is 0.
82, the 0.1) value of the image obtained with the latter was α29.

〔Effect of the invention〕

As is clear from the above examples, according to the present invention, a carrier generation layer, a carrier migration layer,
In an electrophotographic photoreceptor formed by laminating a surface layer, by containing T107 particles in the surface layer, it exhibits excellent development efficiency as an electrophotographic photoreceptor used in a simultaneous method,
It is possible to provide high-contrast images.In addition, by improving the light efficiency during exposure, it is expected that exposure equipment can be made smaller, simpler, and lower in cost.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electrophotographic photoreceptor in an embodiment of the present invention. Figure 2 is a diagram showing how development is performed by the simultaneous method using the electrophotographic photoreceptor of the present invention.

Claims (1)

[Claims] An electrophotographic photoreceptor comprising a carrier generation layer, a carrier transfer layer, and a surface layer laminated on a transparent conductive substrate layer, the surface layer containing titanium oxide (TiO_2) particles.