US 9,176,435 B2Granted

Belt unit and image forming apparatus having the belt unit

AssigneeCanon Kabushiki Kaisha

InventorsHiromi Sakurai, Eiichiro Kimizuka, Yuichiro Inaba, Yasuhiro Fukase, Toshiyuki Watanabe

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Abstract

A belt unit used for an image forming apparatus is provided. The belt unit includes a rotatable endless belt, a plurality of stretching members configured to stretch the belt, an urging member, and a contact and separation unit configured to be able to switch a position of the stretching member urged by the urging member. In moving the stretching member urged by the urging member from the separation position to the contact position, the contact and separation unit makes one end side of the stretching member urged by the urging member in a longitudinal direction coming into contact with the inner surface of the belt faster than the other end side, and temporarily decreases the movement speeds of the both ends of the stretching member in the longitudinal direction respectively before arriving at the contact position.

Claims11

Dependent claims

A belt unit used for an image forming apparatus, the belt unit comprising:

a rotatable endless belt;
a drive roller;
an urging member;
a tension roller that is one of a plurality of rollers to stretch the belt and is pressed from an inner periphery to an outer periphery side of the belt by the urging member and configured to apply tension to the belt,
wherein the tension roller is a roller disposed at a farthest position from the drive roller among the plurality of rollers;
and
a contact and separation unit configured to switch a position of the tension roller to a contact position to come into contact with the inner surface of the belt, or a separate position for separating from the inner surface of the belt,
wherein, the contact and separation unit comprises a shock-absorbing member and a regulating member configured to regulate the position of the tension roller in an urged direction, and
wherein, in a case where moving a position of the tension roller from the separation position to the contact position, the regulating member moves and the shock-absorbing member reduces the movement speed of the regulating member by making contact with the regulating member.

6 more elements

An image forming apparatus comprising:

a rotatable endless belt;
a drive roller that is one of a plurality of rollers to stretch the belt and configured to drive the belt;
an urging member;
a tension roller that is one of a plurality of rollers to stretch the belt and is pressed from an inner periphery to an outer periphery side of the belt by the urging member and configured to apply tension to the belt,
wherein the tension roller is a roller disposed at a farthest position from the drive roller among the plurality of rollers;
and
a contact and separation unit configured to switch a position of the tension roller to a contact position to come into contact with the inner surface of the belt, or a separate position for separating from the inner surface of the belt,
wherein, the contact and separation unit comprises a shock-absorbing member and a regulating member configured to regulate the position of the tension roller in an urged direction, and
wherein, in a case where moving a position of the tension roller from the separation position to the contact position, the regulating member moves and the shock-absorbing member reduces the movement speed of the regulating member by making contact with the regulating member.

6 more elements

Dependencies are inferred from the claim text.