Sheet feeder, image reading apparatus and image forming apparatus

Abstract

A paper press member 240 configured to be capable of advancing and retracting with respect to a paper guide 220 is provided between a paper feed roller 234 and the front end in the paper feed direction of paper loaded in a manual feed tray 230. When a plurality of sheets of paper enter into the press-contact section between the paper feed roller 234 and a reverse roller 235, the reverse roller 235 is rotated in the reverse direction to retract the sheet on the reverse roller side to the manual feed tray 230. At this time, by causing the paper press member 240 to project from the upper surface of the paper guide 220, the sheet to be retracted and the paper press member 240 come into contact with each other, so that the travel amount of the sheet when retracting the sheet is reduced.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2007-124930 filed in Japan on May 9, 2007, the entire contents of which are hereby incorporated by reference.BACKGROUND[0002]1. Technical Field[0003]The present application relates to a sheet feeder capable of certainly preventing multi-feeds (feeding two or more sheets at a time), and an image reading apparatus and an image forming apparatus comprising the sheet feeder.[0004]2. Description of Related Art[0005]As the paper feeding system in an image forming apparatus, two types of feeding systems are used. One is a paper feeding cassette system in which one sheet of paper is taken out of the paper feeding cassette at one time and fed to a printing section, and the other is a manual feedtray system in which paper of irregular size, or only a small amount of paper to be used, is loaded in the manual feed tray, and the paper is taken out of the ...

AI Technical Summary

Benefits of technology

[0014]The present application has been made with the aim of solving the above problems, and it is an object of the present application to provide a sheet feeder comprising, between a paper feed roller and the front end of a stored sheet in a sheet feed direction, a contact member configured to be capable of advancing and retracting and capable of coming into contact with an extra sheet fed by a multi-feed, and thereby capable of reducing the travel amount of sheet when retracting the extra sheet fed by the multi-feed and capable of certainly preventing multi-feeds, and to provide an image reading apparatus and an image forming apparatus comprising the sheet feeder.

Problems solved by technology

However, a member for regulating the paper position is not generally provided for the paper feed direction (particularly for the rear end of the paper loaded in the manual feed tray 530).

If the paper is transported to the printing section in the multi-feed condition, not only the print quality is degraded, but also friction with peripheral members may cause a paper jam and damage to the peripheral members.

Therefore, if the type of paper is thin paper, since the paper has small flexibility, the returning force is not sufficiently transmitted, the paper is bucked, and the return amount is relatively small.

However, when the paper type is thick paper, the paper has strong flexibility, and therefore the returning force of the reverse roller is directly transmitted to the paper and the return amount is large.

In particular, when the paper is small-sized thick paper such as a post card, since the weight of the paper is light with respect to the returning force, the return amount is large and the following problem occurs.

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