JPS60257480A - After image erasing device - Google Patents

Abstract

PURPOSE:To reduce an electric power consumption for after image ereasing and to prepare a pwoer source and the whole device as well in a small size and light-weight by providing an electrifier and a light source which is electrostatically cherged to the same position on an image carrier and exposed thereon simultaneously and a light source. CONSTITUTION:The second electrifier 21 consisting of a charge wire 21a, which generates about 40muA charging current by a high voltage light source 20, and a casing 21b is provided on the after image erasing device of a photosensitive drum 10 is rotated in the direction of an arrow (x) by a control part 26, and simultaneously, the high voltage light source 20 and the other devices are driven following an electric power source 24. The photosensitive drum 10 is rotated, through the first electrifier 11, an exposing device 15, a developing device 16, and the transferrring device 17 to form a toner image on a sheet paper; and when the photosensitive drum 10 reaches the after image erasing position through a cleaning device 18, the surface of the photosensitive drum 10 is irradiated by a light source 23, and simultaneously, corona ions are given to this surface by the charge wire 21a. When the photosensitive drum 10 passes the after image erasing position, a hysteresis error on the surface of the photosensitive drum 10 is erased, and the surface of the photosensitive drum 10 is uniformly destaticized by overall exposure; and thus, the photosensitive drum 10 is in the state where next copying is possible.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to an electrostatic latent image that remains on the image carrier after transfer, in an electrophotographic device or the like that forms a latent image on an image carrier to obtain an image. The present invention relates to an afterimage erasing device that removes afterimages.

[Technical background of the invention and its problems]

71j, in an image forming apparatus such as a secondary photographic apparatus, a photoreceptor, etc., which is a gJ carrier, is sequentially charged, exposed, and developed.

Images are obtained by repeatedly carrying out various processes such as transfer, cleaning, and erasing afterimages, and by transferring and fixing toner images onto sheets of paper that are sequentially conveyed in synchronization with the photoreceptor.

In such devices, after the cleaning process is completed, there are differences in history due to the presence or absence of exposure on the photoreceptor, so it is necessary to simply expose the entire surface of the photoreceptor uniformly and remove the residual charge. If only this is done, a partial difference will occur in the charging characteristics of the photoreceptor at the next charging time, and this will appear as an afterimage in the next image, causing a reduction in image quality. For this reason, a device as shown in FIG. 3 has been conventionally used to erase the afterimage caused by the above-mentioned causes.

That is, in this apparatus, the photosensitive drum 00, which is an image carrier,
A first charging device (12) that charges the same polarity as the first charging device (12) that charges the same polarity as the charging polarity of the device (10)
Second, the photoreceptor drum (10) is uniformly charged again by C'', and then the entire surface is exposed to light using the static elimination lamp 03!; This is to erase the afterimage on the surface of the cleaning device (photosensitive drum QO that has passed through 181).

However, in this device, in order to cover the history difference during no light and to make the electrical characteristics on the photoreceptor drum α uniform at the time of the next charging by the first charging device (It), it is necessary to ! It is necessary to bring IQ to a higher surface potential than when charging by the first charging device (1,1), for example, the charging current of the first charging device On the other hand, the second charging device (121 bands) must be set at a height of about 75 [μA], which is about 1.5 [times] higher than that, and its power consumption is large. Therefore, a large power source is required, and space is also required for the static elimination lamp α'5 around the photoreceptor drum a, which hinders efforts to reduce power consumption, size, and weight of the device. .

[Purpose of redundancy]

This was done based on the condolence sentiments of ``2'' C, reducing the power consumption by 7 d when erasing the afterimage, Xiaomi, '1 Kyogen, and by extension ;・↓ Making the main body smaller and lighter 1 The purpose is to make the remaining 1 bunch of erasers jI'I+'' (5(J().

[・）Hemei no 4:, ); 'tosa] This understanding is to achieve the objective of 1.1. 4-C [Secondly, it is intended to reduce the amount of light and gradient caused by the optical device C2.
1) Hereinafter, an embodiment of the present invention will be described from Kotobuki with reference to FIGS. 1 and 2. Note that the same parts as those of the conventional device are given the same reference numerals, and the explanation thereof will be omitted.

At the afterimage erasing position of the photosensitive drum 11F11, there is a second charging device consisting of a charge wire (2]a) and a body (2]b) that generates a charging current of about 40 [μA] by the high-voltage light source 1. eO is provided. Furthermore, inside the body a (21b), there is a grid wire shield which is a shielding part for shielding the corona ions caused by the charge wire (21a).
A light source (23) is provided so as to overlap the charge wire (2]a) with respect to the photoreceptor drum (1ω). It is formed from a miniature lamp, and its irradiation light exposure device (151) has an exposure h1 of approximately 1.0 (L IJX
-Sec) approximately; 3 times (9)(Lux-sec)
) is set to be. Furthermore, 0a is the power supply for the light source, (::rg is the power supply for the photoreceptor drum (11 and the developing device f).
16) It is a control unit that drives the f1 high FE power supply (20 and power supply (24)) together with the Toshiba device.

With the start of copying, the photosensitive drum (10) is simultaneously rotated in the direction of the arrow
be moved by Then, a toner image is formed on a sheet paper (not shown) through the photoreceptor drum θ1, the first charging device (11), the exposure device (■9, the developing device (1e1), the transfer device 11n, and When the cleaning device (Iυ) reaches the afterimage erasing point, the photosensitive drum 0 (]11 table is illuminated by the light source Q, 3) and corona ions are emitted by the charge wire (2] a). Therefore, by irradiation with light R(2:II), the surface potential of photosensitive drum 4 gradually decreases to 0 (
As the temperature approaches V), corona ions will be injected into the areas where a history difference has occurred during exposure. When the photoreceptor drum 00 passes through the afterimage erasing position, the history difference on the surface of the photosensitive drum 00 has been erased and the charge has been uniformly removed by the entire surface exposure, and the next copy is ready.

With this configuration, even if the charging current due to the second charging device eυ is set as low as about 0.8 [times] the charging current of the first charging device θη, it is possible to erase the history difference and Since static electricity is removed reliably, the power consumption when erasing afterimages is much lower than before, and the power supply is also much smaller and lighter, which facilitates the miniaturization and weight reduction of the main body. ,
Charge wire (2) a) and light source (c) are in the same housing (
In 2] b), since the photoreceptor drum 00) is superposed in a direction perpendicular to the photoreceptor drum 00), it is possible to save space around the photoreceptor drum (field) and to downsize the photoreceptor drum (10).

Note that this invention is not limited to the above-mentioned embodiments and can be modified in various ways. For example, if the charging polarity of the second charging device is the same as the charging polarity of the first charging device, it can be either (positive) or (negative). Although the magnitude of the charging current is not limited, experiments have shown that approximately 0.75 to 1 times the charging current of the first charging device is sufficient to erase history differences. be done.

Further, the type and size of the light source are also arbitrary. Further, the second charging device and the light source may be arranged in any arbitrary manner as long as they can simultaneously charge and irradiate the same position on the image carrier, and may be provided separately. Note that when the second charging device and the light source are arranged as in the embodiment, a transparent shielding member may be provided as a shielding member.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to reduce the surface potential of the image carrier by irradiation with light and to inject partial molecular nicronon ions that have a history difference.
Since the charging current of the charging device can be reduced by about 1/3 to 1/2, the power consumption can be reduced, and the power source can be made smaller and lighter, and the main body can be made smaller and lighter.

In addition, if the second charging device and the light source are arranged perpendicularly to the image carrier in the same housing as in the embodiment, the space near the image carrier can be saved, and the main body can be made more compact. It becomes possible to promote

[Brief explanation of the drawing]

ns 1 and 2 show an embodiment of the present invention.
The figure is a schematic cross-sectional view thereof, FIG. 2 is a schematic block diagram using a cross-sectional view as a part thereof, and FIG. S3 is a schematic cross-sectional view showing a conventional device. DESCRIPTION OF SYMBOLS 10... Photoreceptor drum, jl... First charging device, 21... Second charging device, 22... Grid wire, η... Light source. Agent Patent Attorney Inoue - Male Lineage 1 Figure 7 Figure 2 Figure 3! ! 5 7

Claims (1)

[Scope of Claims] 1. In an image forming apparatus that forms an electrostatic latent image on an image bearing member charged by a first charging device, a second charging device facing the image bearing member after transfer is completed; An afterimage erasing device characterized by a skewer equipped with a charging device and a light source provided near the second charging device and irradiating the charging position on the image carrier when the second charging device is charging. . 2. The second charging device and the light source are arranged in the same housing so as to be superimposed perpendicularly to the photoreceptor through a member that blocks corona ions. Afterimage erasing device. 3. The afterimage erasing device according to claim 1 or 2, wherein the first charging device and the second charging device have the same charging polarity.