JPH0371176A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To effectively remove memory potential without deteriorating fatigue characteristics even when a lamination type selenium photosensitive body is used by destaticizing the photosensitive body by two kinds of light in two steps. CONSTITUTION:An electrifier 2, an exposing light source 3, a developing device 4, a transfer device 5, a separator 6, a 1st destaticizer 7, a cleaning device 8 and a 2nd destaticizer 9 are arranged along the external periphery of the cylindrical lamination type selenium photosensitive body 1. The 1st destaticizer 7 arranged between the separator 6 and the cleaning device 8 uses light having a peak wavelength within the range of >=600nm and <=700nm as destaticizing light and the 2nd destaticizer 9 arranged between the cleaning device 8 and the electrifier 2 uses light having a peak wavelength within the range of >=500nm and <600nm as destaticizing light. The exposure source 3 uses a light source, e.g. a semiconductor laser diode having a peak wavelength in the wavelength area of >=600nm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a reversal development type electrophotographic apparatus equipped with a static elimination mechanism suitable for a selenium photoreceptor for electrophotography.

[Conventional technology]

In recent years, selenium photoreceptors for electrophotography equipped with a photosensitive layer made of a selenium-based material have been developed in order to obtain excellent electrophotographic properties such as high photosensitivity and good repeatability.
Functionally separated laminated photoreceptors, in which functionally separated layers are laminated on a charge generating layer 1 surface protective layer, etc., have become mainstream.

When forming an electrophotographic image using a reversal development method using such a laminated selenium photoreceptor, the static electricity removal process in the image forming process has conventionally been performed at a wavelength of 600 nm to 680 nm between the transfer process and the cleaning process.
A method of removing static electricity using a single red light having a wavelength in the range of 450 nm to 5 QQ nm between the cleaning process and the charging process, Alternatively, a method has been adopted in which static electricity is removed using light in which red light is superimposed on blue light or green light. There is also a method of eliminating static electricity using light in which multiple wavelength components are superimposed using a cold cathode tube or the like.

[Problem to be solved by the invention]

In an electrophotographic image forming process using a reversal development method, when static electricity is removed using a single red light between the transfer process and the cleaning process, the memory potential is reliably removed, but
If the amount of light is too large, the fatigue characteristics of the photoreceptor will deteriorate. There has been a problem in that it is difficult to set an appropriate amount of light that can effectively reduce the memory potential without worsening fatigue characteristics.

Additionally, when static electricity is removed using a single blue or green light between the cleaning process and the charging process, a memory potential tends to remain clearly, and even if the amount of light is increased, the memory potential remains and may cause image defects. Occasionally this occurred. At this time, although it is possible to reduce the memory potential by superimposing red light, a problem arises in that fatigue characteristics tend to deteriorate.

Furthermore, when using a cold cathode tube or the like to use light in which a plurality of wavelength components are superimposed, there is a problem that the ratio of each wavelength component varies depending on the temperature, making it difficult to control the wavelength components.

The problem to be solved by this invention is to solve the above-mentioned problems and to effectively remove the memory potential without deteriorating the fatigue characteristics of a functionally separated laminated type selenium photoreceptor for electrophotography. An object of the present invention is to provide an electrophotographic apparatus of a reversal development type that is equipped with a mechanism for a static elimination process.

[Means to solve the problem]

According to the present invention, the above problem can be solved by reversal development, which is a mechanism in which the electrophotographic image forming process of charging, exposure, development, transfer 1 separation, cleaning, and charge removal is repeated on the electrophotographic photoreceptor mounted inside. In this electrophotographic device, there is a distance of 600 nm between the separation mechanism and the cleaning mechanism.
Equipped with a mechanism for performing first static elimination using a tip having a peak wavelength within a range of 700 nm or less on the JJ, and further provided with a mechanism of 50On+++ or more between the cleaning mechanism and the charging mechanism.
This problem can be solved by providing an electrophotographic apparatus equipped with a mechanism for performing the second charge removal using light having a peak wavelength within a range of less than nm.

[Effect]

The functionally separated laminated selenium photoreceptor for electrophotography has a wavelength of 650n.
In addition to carrier generation from the charge generation layer due to irradiation with long wavelength light of m to 800 nm, carrier generation also occurs in the surface protective layer when irradiated with short wavelength light. In particular, when a selenium-tellurium alloy with a high tellurium concentration is used for the charge generation layer and a material with a composition close to pure selenium is used for the surface protection layer, the film thickness will be between 550 nm and 600 nm, depending on the thickness of the surface protection layer. The surface protective layer contributes to carrier generation for short wavelength light, and the charge generation layer contributes to carrier generation for long wavelength light.By selecting the wavelength of the static eliminating light, the surface protection layer contributes to carrier generation. The carrier generation location can be selected. However, as a characteristic of such a layer structure, there are many energetically deep defects due to changes in structure and composition at the interface between the charge generation layer and the surface protective layer.

When such a selenium photoreceptor is used and carriers are generated in the charge generation layer during the exposure process, holes move toward the substrate due to the electric field, but electrons are trapped at the interface between the charge generation layer and the surface protective layer. Ru.

When static electricity is removed using only red light in this state, carrier pairs are generated on the entire surface of the charge generation layer, and electrons are uniformly trapped on the entire surface of the interface between the charge generation layer and the surface protective layer, forming a negative space charge layer. Therefore, although the memory potential is less likely to occur, it becomes a factor in the decrease in charging.

Therefore, the first charge removal is performed using red light having a peak wavelength within the range of 600 nm or more and 700 nm or less as the minimum amount of light necessary to remove the memory potential, and carriers at the interface between the charge generation layer and the surface protective layer are removed. 500 with high generation efficiency
The second charge removal is performed using light with a peak wavelength in the range of 300 nm or more and less than 600 nm to generate excess carrier pairs at the interface, which accelerates the release of electron traps by red light and performs charge removal at the same time to improve fatigue characteristics. It becomes possible to remove the memory potential while improving the memory potential.

In addition, by setting a time lag between the first static elimination and the second static elimination, the first static elimination mainly removes the residual potential in the unexposed area, and the second static elimination mainly removes the trapped carriers and removes the bulk of the photoreceptor. This will have the effect of removing the space charge inside.

〔Example〕

FIG. 1 is a conceptual diagram of the main parts of a printing device as an embodiment of an electrophotographic apparatus according to the present invention, in which a charger 2, an exposure source 3. Developing device 4. Transfer device 59 Separator 6° First static eliminator 7. Cleaning device 8. A second static eliminator 9 is provided. The first static eliminator 7 disposed between the separator 6 and the cleaner 8 has a 600
The light having a peak wavelength within the range of 700 nm or less on JJ is used as static eliminating light, and the second static eliminator 9 disposed between the cleaning device 8 and the charger 2 has a wavelength of 500 nm or more and 60 nm or more.
Light having a peak wavelength within a range of less than 0 nm is defined as static elimination light. Further, as the exposure source 3, a light source 2 having a peak wavelength in a wavelength range of 600 nm or more is used, for example, a semiconductor laser diode.

Example 1 A charge transport layer made of pure selenium and having a thickness of 50 μm was provided on the outer surface of a cylindrical substrate made of an aluminum alloy.

A charge generation layer with a thickness of 0.5 μm to 1.0 μm made of a selenium-tellurium alloy containing 35% by weight of tellurium, and a 2 μm thick film made of a selenium-arsenic alloy containing 4 at% to 5 at% arsenic.
A photoreceptor prepared by sequentially forming a surface protective layer of ~3 μm using a vacuum evaporation method was installed in the printing device shown in FIG. 1, and the memory potential and fatigue characteristics (charge reduction amount) were evaluated. The memory image was evaluated by printing. At this time, using a 650 nm red LED as the first static elimination light source,
A 570 nm yellow LED is used as the second static elimination light source, and the light intensity of the first static elimination light is set to 5 times and 10 times the half-attenuation exposure amount E1/2 of the photoreceptor, and the light intensity of the second static elimination light is set to 5 times and 10 times the half-attenuation exposure amount E1/2 of the photoreceptor, respectively. Similarly, the evaluation was performed by changing E1/2 to 10 times, 20 times, and 40 times.

As a result, in all the combinations of the above-mentioned first and second charge removal light amounts, no memory potential or memory image was observed, which was good. Regarding the fatigue characteristics, when the light intensity of the first static eliminating light was set to 5 times that of E17°, the amount of charge reduction was small and good.

Example 2 The photoreceptor was evaluated in the same manner as in Example 1 except that the wavelength of the second static elimination light was changed to 520 nm, and the same results as in Example 1 were obtained.

Comparative Example 1 In Example 1, only the first static elimination light was used, and the light intensity was set to E1.
Example 1
When evaluated in the same manner as above, no memory potential was observed, but fogging occurred on the image.

Comparative Example 2 In Example 1, only the second static elimination light was used, and the light amount was set to E.
Eliminate static electricity by changing the ratio of l/2 to 10 times, 20 times, and 40 times,
When evaluated in the same manner as in Example 1, a memory potential was clearly observed.

〔Effect of the invention〕

According to the present invention, in an electrophotographic apparatus of a reversal development type, a first charge removal mechanism using light having a peak wavelength within a range of 600 nm or more and 700 nm or less is provided between the separation mechanism and the cleaning mechanism; In between, a second static elimination mechanism using light having a peak wavelength within a range of 500 nm or more and less than 600 nm is provided. By performing two-step static neutralization on the photoreceptor using two types of light using such an electrophotographic device, it is possible to lower the memory potential without deteriorating fatigue characteristics even when using a laminated selenium photoreceptor. It becomes possible to effectively remove the particles, and a high-quality image can be obtained.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of the main parts of a printing device as an embodiment of an electrophotographic apparatus according to the present invention. 1 photoreceptor, 2 charger, 3 exposure source, 4 developer, 5
Transfer device, 6 Separator, 7 First static eliminator, 8 Cleaning device, 9 Second static eliminator. 1st

Claims (1)

[Claims] 1) Charging the electrophotographic photoreceptor installed inside;
In an electrophotographic apparatus using a reversal development method in which the electrophotographic image forming process of exposure, development, transfer, separation, cleaning, and static elimination is repeated, a peak wavelength within the range of 600 nm or more and 700 nm or less is provided between the separation mechanism and the cleaning mechanism. 500n between the cleaning mechanism and the charging mechanism.
An electrophotographic apparatus comprising: a mechanism for performing second static elimination using light having a peak wavelength within a range of m or more and less than 600 nm.