| 摘要 |
PROBLEM TO BE SOLVED: To smoothly drive a belt with the simple constitution by arranging a plate spring for imparting tension and an elastic member for regulating deformation of the plate spring at reversing time to prevent a tooth skipping by elastically contacting with a timing belt. SOLUTION: When carrying a document, rotational driving force for moving a timing belt 26 in the normal rotation direction A is transmitted via a driving gear 21 of a stepping motor, a driven gear 22 and a driving timing gear 23 to rotate a carrier roller in the normal rotation direction via driven timing pulleys 24, 25. At this time, a plate spring 31 imparts tension to the loosening side of the timing belt 26 via a roller 30. When moving the timing belt 26 in the reverse rotation direction B to move a pickup roller to a standby position, since the loosening side of the timing belt 26 becomes the tension side, the plate spring 31 is deformed by deflecting outside, and is regulated by an elastic member 32 to prevent excessive deformation of the plate spring 31 to maintain a tension state of checking the occurrence of a tooth skipping.
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