JPS6394272A - Transferring device for electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To obtain a distinct image free from toner scattering from a photosensitive body 3 by arranging a stripping lamp for removing an electrostatic latent image from the photosensitive body immediately after a transfer corotron. CONSTITUTION:The stripping lamp 32 for destaticizing the photosensitive body 3 is arranged immediately after the toner image transferring corotron 16 between said corotron and a destaticizing corotron 17. A developed image is transferred to paper 15 by the transfer corotron 16 in the transferring device, but since the paper 15 is charged with negative polarity, toner charged positive polarity is transferred to the paper 15. Since the electrostatic latent image on the photosenstive body 3 is not destaticized scattering of toner from the body 3 can be prevented. After transferring the toner to the paper 15, the electrostatic latent image on the body 3 is destaticized by light radiated from the lamp 32 through the paper 15. Consequently, the paper 15 can be efficiently stripped from the body 3 and a distinct image free from toner scattering can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transfer device for an electrophotographic copying machine, and more particularly to a transfer device that improves the ability to transfer toner to paper.

"Conventional technology" FIG. 4 shows a conventional electrophotographic copying machine 1. As shown in FIG.

While rotating in the direction of the arrow, the photoreceptor 3, which is uniformly charged by the charging corotron 2, is exposed to light by the optical system 4 to form an electrostatic latent image, and further developed by the developing device 5 to form a toner image. Ru. Here, the optical system 4 is the platen 6
A lamp 7 arranged below the lamp 7 and the first to fourth mirrors 8
11 and a lens 12.

The transfer paper 15 is supplied to the photoreceptor 3 from the paper feeder 14 via the feed roll 13, and is transferred to the transfer corotron 16.
The above toner image is transferred by the corona discharge. After the transfer, the paper 15 is neutralized by a static eliminating corotron 17 and then peeled off by a peeling claw 18, and then sent to a fixing device 21 by a conveyor bell 19, where the toner image is fixed. After the toner image remaining on the photoreceptor 3 is cleaned by a cleaning device 22, the charge is removed by a charge removal lamp 23.

Conventionally, when transferring a toner image to the paper 15, the paper 15
In order to improve the transferability of the toner image to the photoreceptor 3, immediately after the development of the photoreceptor 3, the surface potential of the photoreceptor 3 is removed by the pre-transfer lamp 24 to make it easier for the toner image to separate from the photoreceptor 3. The toner image was transferred to the paper 15 by charging the paper 15 with high voltage.

"Problem to be Solved by the Invention" However, in this method, the electrostatic force due to the charge on the photoconductor 3 is weakened, and the toner is easily separated from the photoconductor 3, so the paper 15 comes into contact with the photoconductor 3. There is a problem in that the toner flies off before the image is removed, causing disturbances in the image and deteriorating the image quality.

FIG. 5 shows a process in which the image potential of the photoreceptor 3 changes in the electrophotographic process in a conventional electrophotographic system that performs reversal development. This electrostatic latent image on the photoreceptor 3 becomes a negative image because the image portion is exposed to light and the charge on the photoreceptor 3 is removed, while the background portion retains the charge. When this electrostatic latent image is visualized in the developing process, as shown in FIG. 5(b), by setting the developing bias potential to a high potential and using positively charged toner, the electrostatic latent image is reversely developed and becomes a positive toner. A statue is created.

FIG. 5(C) shows a state where the photoreceptor 3 has been neutralized by the pre-transfer lamp 16, and FIG. 5(d) shows a state after the toner image has been transferred.

Furthermore, if the pre-transfer lamp 24 is removed to eliminate the above-mentioned drawbacks, in the case of an electrophotographic method that performs reversal development, the transfer paper 7 will be charged by corona discharge with a polarity opposite to that of the photoreceptor 3. As a result, the electrostatic attraction between the photoreceptor 3 and the paper 15 is extremely strong, leading to errors in peeling the paper 15 from the photoreceptor 3, resulting in problems such as paper jams.

An object of the present invention is to provide a transfer device that eliminates such problems in electrophotographic copying machines.

``Means for Solving the Problems'' In the present invention, a peeling lamp for removing an electrostatic latent image on a photoreceptor is provided immediately after the transfer corotron, thereby solving the problems of the conventional electrophotographic copying machine. The purpose is to provide equipment.

"Embodiment" An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In addition, those having the same functions as those shown in Figure 4 are:
They will be represented by the same reference numerals and their explanation will be omitted.

In the electrophotographic copying machine 31 shown in FIG. 1, the aforementioned pre-transfer lamp is removed from immediately after the developing device.

Immediately after the toner image transfer corotron 16,
A peeling lamp 32 is provided between the static eliminating corotron 17 and the photoreceptor 3 to eliminate static electricity. As the peeling lamp 32, a tungsten lamp or a fluorescent lamp of 400 lux or more is used.

The charges on the photoreceptor 3 are subjected to imagewise exposure to form an electrostatic latent image as shown in FIG. 3(a).

When this electrostatic latent image is formed by, for example, a digital imaging device, the image portion is exposed to light to eliminate the charge on the photoreceptor 3, and the background portion retains the charge. Become. Therefore, the electrostatic latent image becomes a negative image.

When this negative electrostatic latent image is visualized in the developing process, it is reversely developed by setting the developing bias potential to a high potential and using positively charged toner, as shown in Figure 3(b). A toner image is created.

In this case, if the dark potential of the photoreceptor 3 is, for example, 1000V and the image potential after exposure is 200V, the developing bias is set to 800V.

The image developed in this way is transferred onto the paper 15 by the transfer corotron 16 of the transfer device, but at this time, the transfer corotron 16 generates a negative discharge as shown in FIG. 3(C). to charge the paper 7 negatively.

As a result, the positively charged Toku is shown in Figure 3 (d
) is transferred to paper 15 as shown in FIG.

At this time, since the electrostatic latent image on the photoreceptor 3 has not been neutralized, the number of layers of toner from the photoreceptor 3 can be prevented.

After the toner is transferred onto the paper 15, the electrostatic latent image on the photoreceptor 3 is neutralized by the light from the peeling lamp 32 that passes through the paper 15. When performing this static elimination, use paper 15
Since it is in close contact with the photoreceptor 3, even if a fluorescent lamp of about 10 W is used as the peeling lamp 32, sufficient luminous flux can be applied to the drum, and the static electricity on the photoreceptor 3 can be removed without any problem. be exposed.

Therefore, the electrostatic attraction between the paper 15 and the photoreceptor 3 of the peeling lamp 32 is weakened, and the paper 15 can be effectively peeled off from the photoreceptor 3 by subsequently removing electricity from the paper 15 by the static eliminating corotron 17. The paper 15 after peeling is fixed by the transfer device 21 described above.

FIG. 2 shows another embodiment of the invention.

In the electrophotographic copying machine 33 shown in FIG. 2, the static eliminating corotron 34 has a transparent bottom plate 35 made of plastic or the like.
It is equipped with A peeling lamp 32 is arranged on the back side of the static elimination corotron 34, that is, on the bottom plate 35 side.

In this electrophotographic copying machine 33, while the electrostatic latent image on the photoreceptor 3 is being neutralized by the peeling lamp 32, the static eliminating corotron 34 is
Since static electricity is removed from the paper 15 using
It is possible to realize a transfer device that has high peelability in No. 5 and is free from paper jams.

"Effects of the Invention" As explained above, according to the present invention, by providing a peeling lamp for removing the electrostatic latent image on the photoreceptor 3 immediately after the transfer corotron, a clear image can be obtained without toner scattering from the photoreceptor 3. It becomes possible to realize a transfer device that can obtain high image quality, has high peelability of paper from a photoreceptor, and is free from paper jams.

[Brief explanation of the drawing]

FIG. 1 is a front view showing one embodiment of an electrophotographic copying machine to which the present invention is applied, FIG. 2 is a front view of an electrophotographic copying machine to which another embodiment of the present invention is applied, and FIG. A diagram showing changes in image potential during the electrophotographic process of an electrophotographic copying machine to which the present invention is applied, FIG. 4 is a front view showing an example of a conventional electrophotographic copying machine, and FIG. 5 is a conventional electrophotographic copying machine. FIG. 3 is a diagram of changes in image potential in the electrophotographic process. 3...Photoreceptor, 15...Paper, 16
...Transfer corotron, 17... Static elimination corotron, 24... Pre-transfer lamp, 31.33... Electrophotographic copying machine, 32...
... Peeling lamp, 34 ... Static elimination corotron, 35 ... Transparent bottom plate. Applicant: Fuji Xerox Co., Ltd. Agent

Claims (1)

[Scope of Claims] 1. The toner image formed on the photoreceptor through the steps of charging the photoreceptor, exposure to light, and development is transferred to a transfer paper by discharge of a transfer corotron, and the paper is removed by a static eliminating corotron. 1. A transfer device for an electrophotographic copying machine, characterized in that the transfer device for an electrophotographic copying machine is provided with a peeling lamp for peeling paper from a photoreceptor immediately after a transfer corotron. 2. The transfer device for an electrophotographic copying machine as set forth in claim 1, wherein the peeling lamp is provided on the back of a static eliminating corotron having a transparent bottom plate.