JPH04104186A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To prevent a failure in printing such as fogging by providing a second electrifying part carrying out the electrification of the same polarity as that of a first electrifying part from a transfer part to a first electrifying part. CONSTITUTION:This electrophotographic device is composed of a photosensitive drum 1, electrifying part 2, exposing part 3, developing part 4, a transfer part 5, a transfer after-electrifying part 7, cleaner part 8, and an erasing part 9, and the electrifying part 7 is provided in front of the cleaner 8. The electrifying part 7 is set so as to have a required electrifying quantity for eliminating the fluctuations of a charge on the photosensitive drum 1 by the tailing edge of the sheet 6 when it is separated after being transferred from the transfer part 5 to the electrifying part 2, or above, and simultaneously, so as to carry out the electrification not to exceed the electrifying quantity by the electrifying part 2. Thus, the fluctuations of the charge on the photosensitive drum 1 are eliminated, uniform electrification can be carried out, and the failure in the printing such as the fogging can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrophotographic device using cut paper, and in particular, to an electrophotographic device that eliminates charge fluctuations on a photosensitive drum due to the trailing edge of paper when paper is separated after transfer in an electrophotographic device. and related to uniform charging.

[Conventional technology]

Conventionally, the electrophotographic process of an electrophotographic apparatus using this type of cut paper is comprised of a photosensitive drum, a charging section, an exposure section, a developing section, a transfer section, a cleaning section, and an erasing section.

[Problem to be solved by the invention]

The electrophotographic process of the above-mentioned conventional electrophotographic device using cut paper involves charging in a charging section that applies a positive or negative charge to the photosensitive drum, and an electrostatic image formed by toner charged to the same polarity. A charge of a polarity opposite to that of the charging part is applied to the paper by a transfer unit which applies a charge of a polarity opposite to that of the charging part, and the electrostatic image on the photosensitive drum is transferred to the paper, and then an electrostatic microscope is applied. The paper holding the image is successively separated from the photosensitive drum, but when the trailing edge of the paper is separated, the electrical charge of the opposite polarity to the charged portion on the paper is concentrated on the photosensitive drum. Injected into the charged part, the polarity will be opposite to that of the charged part, or the potential level will be significantly lower than that of the surrounding area.
Even when the next electrostatic latent image is formed, the potential gap with the surrounding area is not resolved even when the electrostatic latent image is formed. Therefore, if an electrostatic latent image is formed on a part where this potential fluctuation occurs, density unevenness will occur, and in the non-latent image area, the potential gap will not be resolved. This method has the disadvantage of causing printing defects such as black streaks and fog due to toner adhesion.

[Means to solve the problem]

The present invention provides an electrophotographic apparatus including a photosensitive drum, a first charging section, an exposure section, a developing section, a transfer section, a cleaning section, and an erasing section. , has a second charging section that performs charging to the same polarity as the first charging section.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a side view showing a first embodiment of the present invention. In FIG. 1, the electrophotographic apparatus of the present invention shows a photosensitive drum 1.
Charging part 2. Exposure section 3. Developing section 4 Transfer section 5. Post-transfer band mold part7. It is composed of a cleaner section 8 and an erase section 9,
The post-transfer band mold section 7 is provided in front of the cleaner section 8.

The post-transfer band portion 7 is provided with an amount of charge required to remove charge fluctuations on the photosensitive drum 1 due to the trailing edge of the paper 6 when the paper 6 is separated after transfer between the transfer unit 5 and the charging unit 2. In addition to the above, the setting is such that charging does not exceed the amount of charging by the charging section 2. Thereby, fluctuations in the charge on the photosensitive drum 1 can be removed and uniform charging can be performed.

FIG. 2 is a side view showing a second embodiment of the invention. In FIG. 2, in this embodiment, a post-transfer band mold section 7 is provided after the cleaner section 8. As shown in FIG.

〔Effect of the invention〕

As explained above, the present invention eliminates charge fluctuations on the photosensitive drum due to the trailing edge of the paper when separating the transfer-assisted paper by additionally installing a charging section, and achieves uniform charging.
This has the effect of preventing printing defects such as density unevenness in electrostatic latent images, black streaks and fog due to toner adhesion in non-latent image areas.

[Brief explanation of drawings]

FIG. 1 is a side view showing a first embodiment of the invention, and FIG. 2 is a side view showing a second embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Photosensitive drum, 2... Charging section, 3... Exposure section, 4... Developing device, 5... Transfer section, 6... Paper, 7
... Post-transfer band mold part, 8... Cleaner part, 9... Erase part.

Claims (1)

[Claims] A photosensitive drum, a first charging section, an exposure section, a developing section, a transfer section,
The electrophotographic apparatus includes a cleaning section and an erasing section, and includes a second charging section that performs charging to the same polarity as the first charging section between the transfer section and the first charging section. An electrophotographic device characterized by: