JPH01312570A - Image forming device - Google Patents

Abstract

PURPOSE:To remove the electric charges of a sheet before the sheet is carried to a transfer part and to obtain an image of excellent quality even when the sheet is electrified by the cause of friction between the sheet and a sheet guide, etc., by providing an earthed destaticizing device on a sheet path on a sheet supplying side near the facing part of an image carrier and a transfer corotron. CONSTITUTION:When the sheet is carried and even when the sheet is electrified by the causes of the friction between the sheet and the sheet guide 18, etc., the destaticizing device 24 is provided on the sheet path in the upstream of the facing part of the image carrier 10 and the transfer corotron 12. Therefore, the destaticizing device 24 removes the electric charges of the sheet. Thus, toner is not attracted to the sheet before the sheet is carried to a transfer area by the transfer corotron 12, whereby blurring, etc., do not occur and the deterioration of image quality is reduced.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an image forming apparatus such as a printer or a copying machine.

Conventional technology In image forming apparatuses such as printers and copying machines that use electrophotographic technology, a charging corotron applies a uniform charge to the surface of a rotating photoreceptor drum, and an exposure device applies an electric charge to the original or image data to be printed. Expose with the corresponding light,
An electrostatic latent image is formed on the photoreceptor drum. The electrostatic latent image formed on the photoreceptor drum is developed and visualized using a developer containing toner.

At the same time, the paper supply device feeds the paper so that it overlaps the toner image on the photoreceptor drum, and the transfer corotron generates a corona discharge with the opposite polarity to the toner from the back of the paper, injecting electric charge into the paper. . As a result, the toner is electrostatically attracted to the paper at the same time that the paper comes into close contact with the photoreceptor drum, and the toner is transferred. The toner image transferred to the paper is fixed by a fixing device to become a permanent image.

The paper supply device includes a paper guide that forms a paper path, a paper transport roller, and the like, and some paper guides are made of plastic molded products from the viewpoint of reducing weight and cost.

Problems to be Solved by the Invention As described above, when the paper guide that forms the paper path is constructed using a plastic molded product, etc., the paper becomes electrically charged due to friction between the paper and the paper guide when the paper is conveyed. However, before the toner reaches the transfer area by the transfer corotron, the toner is attracted to the paper, causing blurred toner scattering (toner scattering) and deteriorating image quality.

The present invention has been made in view of the above points, and its purpose is to prevent the paper from reaching the transfer section even if the paper becomes electrically charged due to friction with a paper guide or the like. Good image quality by removing the charge of
It is an object of the present invention to provide an image forming apparatus.

Means for Solving the Problem A transfer corotron is provided opposite to the image carrier, paper is supplied to the opposing portion of the image carrier and the transfer corotron, and the toner image carried on the image carrier is transferred to the corona by the transfer corotron. The image is configured to be transferred onto paper by electric discharge.

A grounded conductive member, for example, a second
The above-mentioned problem is solved by providing a static eliminator having the configuration as shown in FIGS.

According to the configuration of the present invention, even if the paper is charged due to friction between the paper and the paper guide when the paper is conveyed, the paper path on the upstream side of the opposing portion between the image carrier and the transfer corotron is maintained. In addition, since a static eliminator is provided, the charge on the paper is removed by this static eliminator. As a result, the toner is not attracted to the paper before it reaches the transfer area by the transfer cocotron, and blurring and the like do not occur, so that deterioration in image quality is reduced.

Embodiment An embodiment of the present invention will be described in detail with reference to the drawings.

10 is a photosensitive drum around which a charging device, an exposure device, a developing device, etc. (all not shown) are provided;
2 is a transcription corotron. 14 is a paper cassette in which papers are stacked; 16 is a paper cassette in which paper is loaded one by one from the paper cassette 14;
A paper feed roller 18 is a plastic paper guide that guides the conveyance of paper, and 20 and 22 are a pair of paper conveyance rollers.

24 is a static eliminator, and the static eliminator 24 is grounded to the frame of the main body of the device via a resistor 26.

The resistor 26 is, for example, 100MΩ, and the resistor 2 is
A capacitor 27 may be connected in parallel with 6.

The static eliminator 24 is, for example, as shown in FIG. 2, a member 25 made of aluminum or the like in which a plurality of needle-like members 28 made of stainless steel or carbon are implanted, or as shown in FIG. 3, a stainless steel plate 30 is used. Use a piece with one side cut into both sides.

Returning to FIG. 1, 32 is a daytack saw for peeling off the paper that is in close contact with the photoreceptor drum, 34 is a paper conveyance roller, 35 is a paper guide 1, and 36 is a fixing machine that fixes the toner carried on the paper by heat or the like. It is a device.

The surface of the photoreceptor drum 10 is uniformly charged by the charging corotron, an electrostatic latent image is formed in accordance with the document or print content by the exposing device, and then the electrostatic latent image is developed with toner by the developing device. Ru.

On the other hand, the paper is transferred from the paper feed roller 1-14 to the paper feed roller 1.
6, the sheets are sent out one by one. For paper, use paper guide 18
While being guided by the paper transport rollers 20, the paper is transported first. Next, the paper is further fed by the paper transport roller 22 while being synchronized with the toner image formed on the photoreceptor drum 10 .

At this time, the paper may be charged due to friction with the paper guide 18, etc. (especially at low temperatures and low humidity), but the charge on the paper is removed by the static eliminator 24 provided downstream of the paper transport roller 22. It is supplied to the transfer section. In the transfer section, the toner image on the photoreceptor drum 10 is transferred onto the paper by corona discharge by the transfer corotron 12, and the paper is peeled off from the photoreceptor drum 10 by the detack saw 32.

Next, the paper is moved to the paper guide 3 by the paper withdrawal roller 34.
5, the toner image is thermally fixed onto the paper by a fixing device 36, and the toner image is ejected to an ejection tray (not shown).

With this configuration, the electric charge injected into the paper by the transfer corotron 12 during transfer is transmitted through the paper, and the static eliminator 2
There is little leakage to the frame via the paper, and the efficiency of charge removal from the paper can also be increased.

Effects of the Invention As described in detail above, the present invention is provided with a static eliminator in the paper path on the paper supply side near the facing portion of the photosensitive drum and the transfer corotron, so that the paper is free from frictional charging when the paper is withdrawn. However, since the electric charge is removed by the static eliminator, toner is not attracted to the paper before it reaches the transfer area by the transfer corotron and blur (toner scattering) does not occur, providing an image forming device with good image quality. It has the effect of being able to do it.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram of an embodiment of the present invention, FIG. 2 is a diagram showing an example of a static eliminator, and FIG. 3 is a diagram showing another example of the static eliminator. DESCRIPTION OF SYMBOLS 10... Photosensitive drum, 12... Transfer corotron, 18... Paper guide, 20.22.34... Paper transport roller, 24... Static eliminator, 26... Resistor, 27...・Capacitor. Applicant: Fuji Xerox Co., Ltd.

Claims (1)

[Claims] An image carrier, a transfer corotron facing the image carrier,
means for supplying paper to a portion facing the image bearing member and the transfer corotron; the toner image carried on the image bearing member is transferred between the image bearing member and the transfer corotron by corona discharge by the transfer corotron; An image forming apparatus configured to transfer images onto a sheet of paper conveyed to a transfer section, characterized in that a grounded static eliminator is provided in a paper path on a paper supply side near a portion where the image carrier and a transfer corotron face each other. image forming device.