JPH0458256A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body for TESI enhanced in durability and lengthened in life by forming a light-transmitting conductive substrate or light-transmitting electrode on the surface of the substrate, and laminating a amorphous silicon type photoconductive layer on the substrate. CONSTITUTION:The electrophotographic sensitive body is formed by successively laminating on the light-transmitting substrate 1 the light-transmitting electrode 2 and the amorphous silicon type photoconductive layer 3 or inserting an amorphous silicon type light-transmitting insulating layer 4 between the layers 2, 4. The light- transmitting substrate 1 is formed into a plate, a drum, a sheet, or the like, and made of an inorganic transparent material, such as glass, quartz, or sapphire, or an organic transparent material, such as fluororesin or polyester, or further, optical fiber of celfoc optical plate, and as the light-transmitting electrode layer 2, a transparent conductive material, such as ITO (indium tin oxide), or tin oxide, is used, or a metal, such as A1, Ni, or Au, may be formed into so thin a sheet as made translucent, by vapor depositing or sputtering, and the photoconductive layer 3 and the layer 4 are formed into a film by the glow discharge decomposition method, the ECR method, or the vapor deposition method, or the like, and an element for finishing a dangling bond, such as H or halogen, is contained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic method using an electrostatic latent image transfer method, and in particular to a simultaneous electrostatic latent image transfer method in which electrostatic latent image formation and electrostatic latent image transfer are performed at the same time. The present invention relates to an electrophotographic photoreceptor suitable for an image transfer method.

[Conventional technology]

As an electrophotographic method, an electrostatic latent image transfer method is already known in which an electrostatic latent image on a photoreceptor is once transferred to a recording paper provided with a dielectric layer, and this electrostatic latent image is developed with toner. This electrophotographic method is known as the transfer of electrostatic
Image (Transfer of Electro-S
The method is called the TESI method, and can be roughly divided into the "sequential transfer method" in which forming an electrostatic latent image on a photoconductor and transferring the electrostatic latent image to a recording paper are performed in separate steps.
There is a "simultaneous transfer method" in which image exposure is performed with a photoconductor and recording paper stacked, and electrostatic latent image formation and transfer are performed simultaneously to form an electrostatic latent image on the recording paper.

The basic structure of the photoreceptor used in the latter simultaneous transfer method is one in which a photoconductive layer is laminated on a transparent conductive support. A layer structure in which an insulating layer is formed between them has been proposed (Japanese Patent Publication No. 57-55140 and Japanese Patent Application Laid-Open No. 56-43).
(See No. 665).

In addition, JP-A-49-52643 discloses a layer structure in which an organic photoconductive layer having a higher dark resistance than the photoconductive layer is formed between the conductive support and the photoconductive layer. -4
No. 6067 also proposes a layered structure in which a transparent electrode layer, a photoconductive injection blocking layer, and a photoconductive layer are sequentially laminated on a transparent support.

[The problem that the invention attempts to solve]

The photoconductive layer includes Se, 5e-Te, 5e-As,
Te-As.

ZnO, ZnCd5. CdS, Cd5-nCdCO
5, CdSe, CdTe.

Inorganic materials such as PbO and 5b2S, and organic materials such as polyvinylcarbazole, anthracene, and anthraquinone have been used.

However, the photosensitivity of these photoconductive materials is not high enough, and therefore a large exposure energy (several tens to hundreds of lux-seconds [I!ux-8eC]) is required when forming an electrostatic latent image.
was needed.

Therefore, we have achieved miniaturization by using optical print heads consisting of LED arrays and EL arrays, which have developed rapidly in recent years.
The demand for reducing power consumption could not be met because the sensitivity of the photoreceptor was insufficient.

In addition, in the TESI method, since the photoreceptor is not in contact with a developer or cleaner, there is no wear or scratches on the photoreceptor surface compared to the normal Carlson method, and the life of the photoreceptor can be extended. On the other hand, with conventional photoconductive materials,
The surface hardness of the photoreceptor is not high, which causes problems such as abrasion of the surface of the photoreceptor and scratches on the surface due to contact with electrostatic recording paper or a transfer roller.

Therefore, the present invention was devised in view of the above circumstances, and its purpose is to provide a simultaneous electrostatic latent image transfer method that achieves high sensitivity to light in the visible light range and long life. An object of the present invention is to provide a suitable electrophotographic photoreceptor.

[Means for solving problems]

In the present invention, the surface of a photoreceptor having a light-transmitting support is brought into contact with one main surface of a dielectric material, and at the same time as the image is exposed from the light-transmitting support side, a gap is formed between the other main surface of the dielectric material and the photoreceptor. Regarding an electrophotographic photoreceptor used in a simultaneous electrostatic latent image transfer method in which a voltage is applied, the transparent support itself has conductivity, or a transparent electrode is provided on the surface of the support, and the support thereof It is characterized by having an amorphous silicon-based photoconductive layer laminated on the body.

The present invention is also characterized in that an amorphous silicon-based light-transmitting insulating layer is formed between the light-transmitting support and the amorphous silicon-based photoconductive layer (hereinafter amorphous silicon will be abbreviated as a-3i).

Next, the present invention will be explained in detail.

FIGS. 1 and 2 are diagrams showing typical layer structures of the electrophotographic photoreceptor of the present invention.

In these figures, ■ is a transparent support, and a transparent electrode layer 2 and an a-3i-based photoconductive layer 3 are sequentially laminated on this support 1, or a-3i They are laminated with a translucent insulating layer 4 interposed therebetween.

The transparent support 1 has a shape such as a plate, a drum, a sheet, or a belt, and its materials include transparent inorganic materials such as glass, quartz, and sapphire, as well as fluororesin, polyester, polycarbonate, There are transparent organic resins such as polyethylene, polyethylene terephthalate, vinylon, epoxy, and mylar, as well as optical fibers, selfoc optical plates, and the like.

For the transparent electrode layer 2, a transparent conductive material such as ITO (indium tin oxide), tin oxide, lead oxide, indium oxide, or iodized steel may be used, or A1. A metal such as Ni or Au may be formed thin enough to be semitransparent.

Said a-Si-based photoconductive photoconductive layer-Si-based transparent insulating layer 4
The film is formed by a glow discharge decomposition method, a sputtering method, an ECR method, a vapor deposition method, or the like, and an element for terminating a dangling bond, such as hydrogen (H) or a halogen, is contained during the formation.

In the a-3i photoconductive layer 3, some of the silicon elements are replaced with elements such as carbon, oxygen, nitrogen, germanium, tin, and sulfur to change the physical properties such as conductivity, band gap, and surface hardness as appropriate. Good too.

When an LED head is used as a light source, the light is effectively received by the a-Si layer, but when an EL head is used, the emission wavelength is shifted to the shorter wavelength side, so the a-3i layer receives light effectively. It is preferable to widen the band gap by incorporating elements such as carbon, oxygen, and nitrogen. Furthermore, when a semiconductor laser is used, its emission wavelength is shifted to the longer wavelength side, so that the bandgap may be narrowed by incorporating elements such as a-3ill::germanium and tin.

Furthermore, it is also possible to adjust the electrical properties by adding an element of group 1 [A or group Va of the periodic table] to the a-3i-based photoconductive material 3.

The thickness of the a-3i photoconductive layer 3 is 0.1 to 100 μm
The preferred range is 1 to 50 μm, which makes it easy to ensure the dielectric strength necessary for forming an electrostatic latent image, absorbs exposure light and effectively generates photocarriers, and reduces the residual potential. increase can be suppressed.

The a-3i light-transmitting insulating layer 4 needs to have a band gear knob larger than that of the photoconductive layer 3 so that its inner layer does not absorb light that is effective for generating optical carriers in the photoconductive layer. There is an optical energy gap Eg opt
is preferably set to 1.9 eV or higher.

Further, in order to effectively prevent carrier injection from the electrode layer 2 to the photoconductive layer 3, it is desirable to set the resistivity to 1013 Ωcm or more.

The thickness of the insulating layer 4 is preferably within the range of 0.1 to 10 μm, preferably 0.3 to 5 μm, so that it is easy to ensure the dielectric strength necessary for forming an electrostatic latent image, and it also absorbs exposure light. In this way, photocarriers can be effectively generated, and an increase in residual potential can be suppressed.

Thus, when an electrophotographic photoreceptor with the above configuration is used in a simultaneous electrostatic latent image transfer method, the exposure energy required to form an electrostatic latent image is reduced due to its high photosensitivity, which is compared to conventional photoreceptors. It is now possible to use a compact and low power consumption exposure light source, such as an LED head or an EL head, which was previously unavailable.

It also has a higher surface hardness than conventional photoreceptors, making it possible to provide an electrophotographic photoreceptor with a long life. Incidentally, the Vickers hardness of the amorphous As2Se3 layer is 150 kg/mm'', and the hardness of the organic photoconductive layer is less than that, whereas the Vickers hardness of the a-3i layer is 1500 to 2000 Kg/mm''. , and when carbon, oxygen, and nitrogen are added to it, the hardness becomes even higher.

Furthermore, when an a-3i transparent insulating layer 4 is formed as shown in FIG. 2, the dielectric strength of the photoreceptor can be increased and transfer of background charges can be suppressed, resulting in high contrast and
Good images with no background fog can be obtained.

In the above-mentioned electrophotographic photoreceptor, the transparent electrode layer 2 is laminated on the transparent support 1, or the transparent support 1 is formed using a conductive material, and the electrode is formed on it. The electrode layer 2 may be made unnecessary by providing a function.

〔Example〕

Next, examples of the present invention will be described.

(Configuration of electrophotographic copying machine) FIG. 3 shows the configuration of the electrophotographic copying machine used in this example.

In the figure, an LED head 6 and an erase lamp 7 are arranged inside a photosensitive drum 5, which is formed by sequentially laminating a transparent electrode layer 2 and a photoconductive layer 3 on a drum-shaped transparent support 1. A voltage can be applied to the transparent electrode layer 2 by a DC power source 8. 9 is a conductive roller, 10 is a developing device, and 11 is a fixing device, and an electrostatic transfer paper 12 is conveyed between the photoreceptor 5 and the conductive roller 9.

In such a configuration, first, a voltage is applied between the transparent electrode layer 2 of the photoreceptor drum 5 and the conductive roller 9 via the electrostatic transfer paper 12, and image exposure is performed using the LED head 6. A latent charge image is formed on the surface of the photoreceptor according to the image exposure by the generation of light carriers in the conductive layer 3 and the transport of the light carriers, and then, as the photoreceptor drum 5 rotates,
When the electrostatic transfer paper 12 is separated from the photoreceptor drum 5, a charged latent image is transferred onto the electrostatic transfer paper 12 due to air discharge in the gap between the two. This electrostatic latent image is subsequently developed as a toner image by a developing device IO, and fixed by a fixing device 11. On the other hand, the photoreceptor drum 5 is then irradiated with light from the erase lamp 7 to erase residual charges, and is used for forming the next latent image.

(Example 1) An ITO layer was formed as a transparent electrode layer 2 on the circumferential surface of a transparent cylindrical glass substrate to a thickness of 1,000 mm by electron beam evaporation, and then a capacitively coupled glow discharge decomposition device was placed on top of the ITO layer. An a-3i photoconductive layer was laminated using the film forming conditions shown in Table 1.

[Margin below]

Table 1 The gas is diluted with H2 at a concentration of 20 ppm.

The photoreceptor thus obtained was installed in the electrophotographic copying machine shown in FIG.
0 nm, exposure amount 1. While performing image exposure under conditions of OuJ/cm2, a voltage of +500 .mu. was applied between the photoreceptor and the electrostatic transfer paper via a conductive roller.

Then, an electrostatic latent image is formed on the electrostatic transfer paper, and then this electrostatic latent image is developed using a two-component developing machine using negatively charged toner, and the resulting toner image is thermally fixed. An image corresponding to the exposed area was obtained. When this image was evaluated, it was 0. D.
The image had an image density of 1.0, had no background fog, and had good resolution.

(Example 2) In producing the electrophotographic photoreceptor of (Example 1), a-
Photoconductive fine powder CdSn Cd instead of Si-based photoconductive layer
A photoconductive layer having a thickness of 30 μm was formed by dispersing CO5 (0.8≦n≦1.0) together with a metal activator in a near-acrylic resin and thermosetting it, and the other configuration was the same as in Example 1.

The thus obtained photoreceptor was mounted on an electrophotographic copying machine in the same manner as in Example 1, and an LED head was arranged inside the photoreceptor, and image exposure was carried out under the conditions of a wavelength of 6601 m and an exposure amount of 1.0 μJ/cm2. During this process, a voltage of 1,800 μm was applied between the photoreceptor and the electrostatic transfer paper via a conductive roller. Then, an electrostatic latent image is formed on the electrostatic transfer paper, and then this electrostatic latent image is developed using a two-component developing machine using positively charged toner, and the resulting toner image is thermally fixed. An image corresponding to the exposed area was obtained. When this image was evaluated, it was found that due to insufficient photosensitivity of the photoconductive layer, a sufficient electrostatic latent image was not formed, and the image had almost no density.

(Example 3) An ITO layer is formed on the surface of a transparent cylindrical glass substrate to a thickness of 1000 nm by electron beam evaporation, and then an amorphous silicon layer is formed using a capacitively coupled glow discharge decomposition apparatus under the film forming conditions shown in Table 2. A photoconductive layer made of carbide (hereinafter abbreviated as a-3iC) was laminated.

[Margin below]

Table 1: The thus obtained photoreceptor was installed in an electrophotographic copying machine, and an LED head was arranged inside the photoreceptor, and image exposure was performed under the conditions of a wavelength of 6600 m and an exposure amount of 1.0 μJ/cm2, while
150 mm between the photoreceptor and the electrostatic transfer paper via a conductive roller.
A voltage of 0 ■ was applied. Then, an electrostatic latent image is formed on the electrostatic transfer paper, and then this electrostatic latent image is developed using a two-component developing machine using positively charged toner, and the resulting toner image is thermally fixed and exposed. An image corresponding to the area was obtained. When this image was evaluated, it was found to be 0.0, similar to (Example 1). D, is 1. The image had an image density of O, no background fog, and good resolution.

In this image evaluation test, the LED head of the exposure light source was changed to an EL head with a wavelength of 585 nm, and the exposure amount was 0.
When an image was obtained in the same manner while performing image exposure under the condition of 9μJ/cm'', a similarly good image was obtained, and a-3
It was confirmed that the i-photoconductive layer exhibited higher sensitivity to light with a shorter wavelength than the i-photoconductive layer.

(Example 4) An ITO layer was formed on the circumferential surface of a transparent cylindrical glass substrate to a thickness of 1000 nm by electron beam evaporation, and then a
- A SiC insulating layer and an a-3i photoconductive layer were laminated.

[Margin below]

The thus obtained photoreceptor was installed in an electrophotographic copying machine, and an LED head was arranged inside the photoreceptor to generate a wavelength of 6601 m.
, while performing image exposure at an exposure amount of 1.0 μJ/cm2, a voltage of +700 μ is applied between the photoreceptor and the electrostatic transfer paper via a conductive roller to generate electrostatic charge on the electrostatic transfer paper. A latent image was formed. Subsequently, this electrostatic latent image was developed using a two-component developing machine using negatively charged toner, and the resulting toner image was thermally fixed to obtain an image corresponding to the exposed area. When this image was evaluated, it was 0. D, had an image density of 1.3, had no background fog, and had good resolution.

(Example 5) 170 layers were formed on the circumferential surface of a transparent cylindrical glass substrate to a thickness of 1000 layers by electron beam evaporation, and then a capacitively coupled glow discharge decomposition device was used to form the film under the film forming conditions shown in Table 4.
-3i insulation and a-3iCi conductive layers were sequentially laminated.

[Margin below]

The thus obtained photoreceptor was installed in an electrophotographic copying machine, and an LED head was placed inside the photoreceptor to perform image exposure under the conditions of a wavelength of 6600 m and an exposure amount of 1.0 μJ/cm.
170 mm between the photoreceptor and the electrostatic transfer paper via a conductive roller.
A voltage of 0 ■ was applied. Then, an electrostatic latent image is formed on the electrostatic transfer paper, and then this electrostatic latent image is developed using a two-component developing machine using positively charged toner, and the resulting toner image is thermally fixed and exposed. An image corresponding to the area was obtained. When this image was evaluated, it was 0. The image had an image density of D, or 1.3, had no background fog, and had good resolution.

In this image evaluation test, the LED head of the exposure light source was changed to an EL head with a wavelength of 585 nm, and the exposure amount was 0.
When an image was obtained in the same manner while performing image exposure under the condition of 9 μJ/cm, a similarly good image was obtained.
It was confirmed that the i-conducting layer exhibits characteristics of high sensitivity to light with a shorter wavelength than the i-conductive layer.

〔Effect of the invention〕

As described above, according to the electrophotographic photoreceptor of the present invention, since the a-3i-based photoconductor with high photosensitivity is used, the exposure energy when forming an electrostatic latent image is reduced, and as a result, the LED
It was possible to use a compact and low power consumption exposure light source such as a head or an EL head.

Further, according to the present invention, it was possible to provide an electrophotographic photoreceptor for TESI that achieved high durability and a long service life due to its excellent surface hardness.

Furthermore, according to the electrophotographic photoreceptor of the present invention, good images with high contrast and no fogging were obtained.

[Brief explanation of drawings]

1 and 2 are cross-sectional views showing the layer structure of the electrophotographic photoreceptor of the present invention, and FIG. 3 is an explanatory view of the TESI method. l...Transparent support 2...Transparent electrode layer 3...Amorphous silicon-based photoconductive layer 4...Amorphous silicon-based light-transparent insulating layer

Claims (2)

[Claims] (1) The surface of the photoreceptor having a transparent support is brought into contact with one main surface of the dielectric, and at the same time as the image is exposed from the side of the transparent support, the other main surface of the dielectric is placed between the photoreceptor and the other main surface of the dielectric. An electrophotographic photoreceptor used in a simultaneous electrostatic latent image transfer method in which a voltage is applied, wherein the transparent support itself has conductivity or a transparent electrode is provided on the surface of the support, and the transparent support has conductivity. An electrophotographic photoreceptor characterized in that an amorphous silicon-based photoconductive layer is laminated on a support. (2) The electrophotographic photoreceptor according to claim 1, wherein an amorphous silicon-based light-transmitting insulating layer is formed between the light-transmitting support and the amorphous silicon-based photoconductive layer.