| 摘要 |
<p>1289671 Feeding sheets and webs RICOH KK 1 Jan 1970 [25 Jan 1969] 68/70 Heading B8R A photocopying machine comprises a support 1a for a roll of copying paper 1; solenoid actuated feed rollers 3 for advancing the paper to a cutter 4; charging, exposure and developing devices 5, 6, 8; and a photosensitive device 9, 10 which produces a signal to stop the operation of the feed rollers 3 in the absence of paper on the support 1a. As shown, the roll of paper is illuminated by a light source 9 and the reflected light is detected by a photo-conductive element 10. The length l 0 of the path P o between the point of reflection A and the cutter 4 is greater than the length 1 1 of the path P 1 between feed rollers 8a, 8b of the developing device 8, 1 1 being the length of sheet which is required to be cut from the roll. Thus, if paper is present at point A there is a sufficient length available to produce at least one sheet of correct length; when, however, the paper is almost exhausted so that its length in the path P o is less than 1 1 and is therefore not suitable for use, it will not be present at the point A. This absence is detected by the element 10 which produces a signal to inhibit operation of the feed rollers 3, so that the unsuitable tail-end of the roll is not advanced further into the machine. A suitable transistorized control circuit is described with reference to Fig. 2 (not shown).</p> |
