JPH01291279A - Electrophotographic device constituted by using amorphous silicon photosensitive body - Google Patents

Abstract

PURPOSE:To eliminate the light which does not contribute to the removal of the host by reflection of main destaticizing light and hinders the drop of potential so that stable image quality is obtd. by specifying the quantity of the reflected light reflecting from a photosensitive body between the irradiation position of the main destaticizing light and a main electrostatic charger. CONSTITUTION:A casing 8-1 which allows the photosensitive body to be irradiated with the light only in the surface direction is provided to a main destaticizing light source 8 and a sheet metal 8-2 which is subjected to an antireflection treatment on the surface opposite to the photosensitive body, for example, to black painting, is simultaneously used, by which the quantity of the reflected light between the irradiation position of the main destaticizing light and the main electrostatic charger 2 is decreased to <=5% as compared to the quantity of the main destaticizing light cast to the photosensitive body 1. The phenomenon that the reflected light does not contribute to the removal of a light memory and degrades only the electrostatic chargeability is thus eliminated by suppressing the irradiation of the photosensitive body 1 by the reflected light.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electrophotographic apparatus using an amorphous silicon photoreceptor.

[Prior Art] Amorphous silicon photoreceptors have high surface hardness, exhibit high sensitivity to long wavelength light such as semiconductor lasers (770 nm to AOONM), and show almost no deterioration due to repeated use, making them especially suitable for high-speed copying. It is prized as a photoreceptor for electrophotography in machines and laser beam printers.

FIG. 3 shows an example of a conventional electrophotographic apparatus using such an amorphous silicon photoreceptor. In Figure 3,
Reference numeral 1 denotes an amorphous silicon photoreceptor, which is configured as a rotating cylindrical photoreceptor drum that rotates in the direction shown by the X-rays in a direction perpendicular to the plane of the paper. Around the photoreceptor 1, there are a main charger 2 that is close to the photoreceptor and uniformly charges the photosensitive layer on the surface of the photoreceptor, an image information imparting means 3 for forming an electrostatic latent image, and a means for visualizing this image. A developing device 4 for transferring the developed image onto a transfer material, a transfer charging device 5 for transferring the developed image onto a transfer material, a separating means 6 for separating the transfer material from the photoreceptor, a cleaning device 7, and a main static eliminating light source 8 are arranged in parallel. It is. The cleaning device 7 includes
A cleaning blade 7-1 made of a suitable elastic material such as urethane rubber is provided, and one edge of the cleaning blade 7-1 is in pressure contact with the counter in one direction or in the trailing direction, and does not contribute to the transfer at the transfer site and cleans the surface of the photoreceptor. Any residual toner remaining on the blade is scraped off the surface when it reaches the blade location.

[Problems to be Solved by the Invention] In an electrophotographic device using an amorphous photoreceptor as described above, the amorphous silicon photoreceptor has many tangling bonds (dangling bonds), and these are localized. It becomes a level and captures some of the photocarriers, reducing their mobility or reducing the recombination probability of photogenerated carriers. Therefore, in the image forming process, some of the carriers generated by exposure are released from the localized level at the same time as an electric field is applied to the photoreceptor during the next charging step, and the surface potential of the photoreceptor is There is a difference in
This ultimately appears as image unevenness called ghost.

In order to erase such ghosts, it is common practice to perform uniform exposure in the main static elimination process to increase the amount of latent carrier inside the photoreceptor and make it uniform over the entire surface, thereby erasing non-memory. be. It is possible to eliminate ghosts more effectively by increasing the amount of light or by bringing it closer to the spectral sensitivity peak of the amorphous silicon photoreceptor (approximately 680 nm to 700 nm).However, as mentioned above, the amorphous silicon photoreceptor Silicon photoreceptors are susceptible to optical memory, and if the main charge removal light is made too strong, the excess carriers latent inside the photoreceptor will enter the main charging process before recombining, reducing charging efficiency. In other words, in the charging process, the initial phase is a recombination process of carriers.
Then, since a step of increasing the surface potential is taken, the amount of carriers on the photoreceptor immediately before the charging step greatly influences the level of the subsequent surface potential, that is, the charging ability.

Therefore, it is preferable that the main neutralizing light be applied a certain period of time before the main charging to erase the optical memory and proceed to the charging step after the carriers have been generally recombined. However, in copying machines that are becoming faster and more compact, it is difficult to take a long time for this recombination (at least 100m5ec or more), and due to constraints on the charging ability, that is, securing the dark potential, some ghosts may occur. The situation was such that we had no choice but to cut it off.

However, since the ghost elimination mechanism is based on a mechanism in which carriers are generated in excess as described above, the carriers generated by low intensity light such as the reflected light from the main static elimination light source after the main irradiation are It has almost no effect on erasing ghosts, and not only has the negative effect of reducing the charging ability, but also often causes the incident position on the photosensitive layer to move closer to the main charger due to reflection, further reducing the charging ability. The research conducted by the present inventors has revealed that this effect is frequently caused.

As the main static neutralization light source, point 5 is to eliminate ghosts and ensure charging ability.
In many cases, an LED array is used, which can strictly control the wavelength and light intensity, and is placed between the cleaner and the charger. However, with the conventional device configuration, there is a problem in that even though the ghost level is the same between devices, there is a large variation in charging ability, and due to charging ability constraints, there are cases where it is necessary to weaken the static elimination light to eliminate the ghost. Ta.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic apparatus that maximizes the ghost erasing ability of the main static eliminating light that is essential for ghost erasing, minimizes deterioration in charging ability, and has excellent overall performance.

[Means for Solving the Problems] As described above, the present invention provides a main static eliminator light in order to maximize the ghost erasing ability of the main static eliminator light, which is essential for ghost erasing, and to minimize deterioration in charging ability. By providing an anti-reflection member that is orthogonally incident on the surface of the photoreceptor and absorbs the reflected light from the photoreceptor, the amount of main neutralizing light that erases the residual potential of the photoreceptor before the main charging process is reduced. Provided is an electrophotographic apparatus using an amorphous silicon photoreceptor, characterized in that the amount of reflected light reflected from the photoreceptor between a static eliminating light irradiation position and a main electronic device is 5% or less.

[Function] According to the present invention, the main static elimination light is made orthogonally incident on the photoconductor to prevent reflected light, and an anti-reflection member is provided to suppress the irradiation of the reflected light to the photoconductor, thereby removing optical memory. It is possible to eliminate the phenomenon that only reduces the charging ability without being involved in the electrification.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the invention. In FIG. 1, the same parts as those of the conventional electrophotographic copying apparatus using an amorphous silicon photoreceptor described with reference to FIG. 3 are designated by the same reference numerals, and the explanation thereof will be omitted.

In the embodiment shown in FIG. 1, a casing 8-1 is provided in which the main static elimination light source 8 emits light only in the direction of the surface of the photoreceptor, and at the same time anti-reflection treatment is applied to the surface facing the photoreceptor, for example, the surface is coated with black paint. By using the scraped sheet metal 8-2, the amount of light reflected between the irradiation position of the main charger and the main charger is 5% or less compared to the amount of the main charger that hits the photoreceptor.

In the embodiment shown in FIG. 1, a 27 μm amorphous silicon photosensitive layer deposited on an aluminum cylinder was used as the photosensitive member, the diameter of the photosensitive member was 108 mm, the process speed was 340 mm/sec, and the casing 8-1 By variously changing the shape and coating material of the sheet metal 8-2, the light intensity ratio B/A between the direct light irradiation position A and the reflected light irradiation position B is set to 0.01. O, [1
The relationship between ghost and charging ability was examined by varying the angle of 5,0,1°015. The results are shown in Table 1.

Table 1 In the above experimental examples, when the reflectance B/A was reduced to 0.05, it was observed that the ghost level did not change and only the charging ability decreased. In the conventional example, deterioration of ghosting was observed, which made the charging ability equivalent to that of the present experimental example.

FIG. 2 shows a second embodiment of the invention. In this case, a casing 8-3 made of a light-shielding flexible material such as carbon-dispersed polyethylene is provided as a casing member in place of the casing 8-1 and the sheet metal 8-2 treated with anti-reflection treatment shown in FIG. Show the configuration. Regarding this example, the first
The experiment was conducted under the same conditions as the experiment conducted for the example shown in the figure. The experimental results are shown in Table 2.

Table 2 The same trends as shown in Table 1 were observed in the above experiments.

[Effects of the Invention] The present invention has the above-described structural action, and in order to maximize the long life and high stability of the amorphous silicon photoconductor, the present invention eliminates a potential drop that does not involve ghost removal due to reflection of the main neutralizing light. By removing the harmful light, it has become possible to obtain an electrophotographic device with stable image quality.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing a main part of a first embodiment of an electrophotographic apparatus according to the present invention, and FIG. 2 is a schematic side view showing a main part of a second embodiment of an electrophotographic apparatus according to the present invention. 3 are similar diagrams showing a conventional example. 1...Amorphous silicon photoreceptor 2...Main charger 8...Main static elimination light source

Claims (1)

[Claims] 1. In an electrophotographic apparatus using amorphous silicon, the main charge removal light irradiation position and the main charger are different from each other in comparison to the light intensity of the main charge removal light that erases the residual potential of the photoreceptor before the main charging step. An electrophotographic apparatus characterized in that the amount of reflected light reflected from the photoreceptor between the photoreceptors is 5% or less. 2. The electrophotographic apparatus according to claim 1, further comprising an anti-reflection member that causes the main static elimination light in the main static elimination step to be incident orthogonally onto the surface of the photoreceptor and absorbs reflected light from the photoreceptor.