Belt unit and image forming apparatus

摘要

A belt unit is provided with an endless belt, a driving roller, and a pair of guide ribs. The driving roller is disposed on an inner peripheral surface side of the endless belt and drives the endless belt. The pair of guide ribs is placed on each opposite widthwise end of the inner peripheral surface of the endless belt and contacts both end faces of the driving roller, thus preventing meandering of the endless belt. Additionally, the driving roller is equipped with a low friction region at both opposite lengthwise ends in a predetermined width and the low friction region is configured to have a friction coefficient that is lower than a friction coefficient of a region adjacent to the low friction region.

主权项

1. A belt unit comprising:
an endless belt; a driving roller comprising a cylindrical body that is disposed on an inner peripheral surface side of the endless belt and that drives the endless belt; and a pair of guide ribs that is placed on each opposite widthwise end of the inner peripheral surface of the endless belt and that contacts both end faces of the driving roller, thus preventing meandering of the endless belt, wherein the driving roller is equipped with:
a low friction region at least at both opposite lengthwise ends of the cylindrical body in a predetermined width; andan adjacent region adjacent to the low friction region, the adjacent region being on an outer peripheral surface of the cylindrical body of the driving roller, the adjacent region being made of a different material which is different from a material of the low friction region, and wherein the adjacent region has a friction coefficient that is higher than a friction coefficient of the low friction region, the cylindrical body of the driving roller is made of the same material as the low friction region, the driving roller is equipped with an uneven level on an outer peripheral surface of the driving roller, the uneven level being placed at each boundary between the adjacent region and the low friction region; and a diameter of the adjacent region is set to be longer than a diameter of the low friction region in such a manner that the uneven level is formed.