Sheet providing device and image forming device

Abstract

A sheet feeder (3) includes a pickup roller (51) for feeding a sheet on a tray (31) toward a predetermined processing position, an arm member (50) rotatably supporting the pickup roller, a rotary shaft (521) supported on the housing (30) to be rotatable about an axis thereof, a coupling member (57) for coupling the arm member and the rotary shaft, a pivoting mechanism (56) for pivoting the arm member via the rotary shaft so that the pickup roller shifts its position between a feeding position and a retracted position, and a controller (8) for controlling the operation of the pivoting mechanism. The controller controls the arm member to pivot in such a direction that the pickup roller moves toward the retracted position when a sheet is placed on the tray.

Description

technical field [0001] The present invention relates to a sheet feeding device that feeds a sheet to a predetermined processing position, and an image forming apparatus including the sheet feeding device as an automatic document feeder. Background technique [0002] An image forming apparatus that forms an image on a recording sheet based on a document image on the document sheet includes an apparatus main body that performs image formation, an automatic document feeder, and an image reading unit. In an image forming apparatus employing an electrophotographic method, a document sheet placed on a document tray of an automatic document feeder is first conveyed toward an image reading position of an image reading unit, and then the document sheet is optically read. Image, on the other hand, charges the photosensitive drum in advance, irradiates the surface of the photosensitive drum with laser light modulated according to the image data of the original image to form an electros...

AI Technical Summary

Problems solved by technology

If the pick-up roller is lowered, the following disadvantages sometimes occur: the space in the height direction where the original sheet can be placed is narrowed, causing the original sheet to be rolled up when the original sheet is placed; or, it is difficult to make the original sheet The leading edge in the paper feed direction is aligned, resulting in overlapping feed; etc.

[0005] In the device of prior art 1, if a coil spring with a large holding force is used, the problem of the lowering of the pickup roller can be solved, but the torque required for the swing of the arm member becomes large, and it is necessary to increase the swing of the arm member. The problem with the capacity of the motor

In addition, in the device of prior art 2, when the automatic document feeder is powered on, the action of making the pickup roller stand by at a predetermined position is performed, but the problem of the pickup roller falling after the power is turned on cannot be solved.

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