| 摘要 |
PROBLEM TO BE SOLVED: To detect average speed variation of a whole belt without nipping a belt by arranging a speed detecting roll at a position a specific distance apart from a belt driving roll. SOLUTION: An intermediate transfer belt B is transported through a primary transfer region Q3 in which a toner image on the surface of an image carrier body 16 is primary-transferred on the surface of a belt B and a secondary transfer region Q4, in which a toner image primary-transferred on the surface of the belt B is secondary-transferred on a recording sheet S. A belt driving roll 26 and a speed detecting roll ER are arranged interposing the primary transfer region Q3 between them. The speed detecting roll ER and the belt driving roll 26 are arranged apart from each other by >= a quarter of circuit length of the belt B. Thereby, the speed detecting roll ER can detect averaged speed of the belt B without being affected by speed variation of the belt B caused at an adjacent position of the belt driving roll 26. |
