Sheet feeding apparatus and image forming apparatus

Abstract

A sheet feeding apparatus includes an endless attraction member (200) attracting a sheet and rotating, and the attraction member (200) includes a plurality of electrode pattern areas. Each of the electrode pattern areas includes first and second electrodes (510 and 511) supplied the voltages from a power feed portion respectively. The electrode pattern areas are arrayed in the circumferential direction in such a manner that the electrode pattern areas are electrically insulated each other, and each circumferential direction length of the electrode pattern areas is set shorter than a circumferential direction length, between the power feed portion and the discharge portion, of the attraction member.

Description

TECHNICAL FIELD[0001]The present invention relates to a sheet feeding apparatus and an image forming apparatus, and more specifically, to a configuration to feed a sheet by using an electrostatic attraction force.BACKGROUND ART[0002]In an image forming apparatus such as a copying machine and a printer, many apparatuses adopting a friction separation-type system as a system for conveying sheets from a cassette in which the sheets are stacked. In the friction separation system, a sheet feed roller formed of a rubber material is rotated while being pushed against the sheet stacked in the cassette, so as to convey an uppermost sheet from the sheets stacked on an intermediate plate. In order to prevent multiple feeding where a lower sheet in contact with the uppermost sheet is conveyed with the uppermost sheet, known configurations such as pressing the sheet against a separation pad during conveyance and applying a conveying force in a direction opposite to the conveyance direction with ...

AI Technical Summary

Benefits of technology

The present invention is about a device that feeds sheets of paper and a machine that makes images on paper. The device doesn't require switching between power and discharge, which means that it can create static force and discharge at the same time. This prevents a decrease in productivity.

Problems solved by technology

In such friction separation configurations, noise caused during the feeding operation becomes a problem, since sheets are conveyed while applying a large vertical drag to the sheets.

This residual electric charge will deteriorate the electrostatic attraction force of the electrostatic attraction belt, so that it is required to discharge the residual electric charge.

According to the above-mentioned configuration, the voltages are applied to the whole area of the electrostatic attraction belt during the operation of attracting the sheet, so that sufficient discharging effect cannot be achieved by having the discharge portion contact the electrostatic attraction belt in this state.

Therefore, the productivity may be deteriorated significantly.

In an attempt to apply the power feed configuration disclosed in Japanese Patent Application Laid-Open Publication No. 2001-48370 to the apparatus disclosed in Japanese Patent Application Laid-Open Publication No. 2012-140224, since the attraction range is moved up and down, it is difficult to have the power feed brush come into secure contact with electrodes disposed on the electrostatic attraction belt to feed power.

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