| 摘要 |
A belt unit includes a first roller; a second roller; a belt extended with at least the first roller and the second roller; a first supporting member for supporting the first roller; a second supporting member disposed to be freely rotatable relative to the first supporting member for supporting the second roller; a switching member for switching the first supporting member and the second supporting member between a first state for applying tension to the belt and a second state for loosening the belt; and a regulating member for regulating the second supporting member to rotate. |
