| 摘要 |
PURPOSE:To make any damage to a sheet edge preventable from occurring, by installing a light projecting device and a reflected light receiving device in ach tip end of a head and a pusher, while avoiding the forcible insertion of the head and the pusher into the side of a sheet pile. CONSTITUTION:When output of a light receiving element 8 exceeds the specified level while a head 1 searches for paper board P, a fact that a tip end of the head 1 comes too much nearer to the side of a sheet pile is detected whereby the head is stopped and a warning device is made to operate. And, since the light emitted out of an end face of an optical fiber 9 of a pusher 2 is incident into a gap g between upper and lower sheet surfaces at a low incident angle, reflection out of these sheet surface approximates to regular reflection, and the reflected light repeats its reflection toward the gap g, then is gradually absorbed so that when a finger f adjoins the gap f, an output level of the light receiving element is low. Therefore, when the output level is higher than a certain level, it is so judged that gap formation by the head 1 is insufficient or the gap is not yet formed, whereby a forward movement of the pusher is stopped, starting a warning motion, thus any damage to the sheet is prevented from occurring. |
