| 摘要 |
PURPOSE:To extend the life of a sprocket by uniformizing the abrasion of the outer periphery of the sprocket caused by the contact with a paper delivery hole, by providing the sprocket in a freely revolvable manner with respect to the shaft thereof. CONSTITUTION:A sprocket 6 can be simply attached to a rotary wheel 5 in such a state that a holding spring plate 9 is pressed to the direction shown by an arrow A by a finger chip and the detachmement thereof can be performed in the same way. The diameter of a circular hole 5a and that of the pin part of the sprocket 6 are selected so as to be capable of being loosely fitted and the sprocket 6 is held to the circular hole 5a of the rotary wheel 5 in a freely rotatable manner by the holding spring plate 9. Therefore, when the rotary wheel 5 is rotated to the direction shown by an arrow B, the outer periphery of the large diameter part 6a of the sprocket 6 is intermittently contacted with a friction body 8 and, at this time, the sprocket 6 is intermittently rotated to the direction shown by an arrow C every at an irregular angle with respect to the central shaft of said sprocket 6. As a result, the entire periphery of the sprocket 6 is almost equally contacted with a paper delivery hole and it can be prevented that only a part of the sprocket is abraded and the life of the sprocket wheel can be extended. |
