| 摘要 |
PURPOSE:To retain a fixed amount of slackening to keep the lower end of the slackening portion and the floor from contacting each other and prevent lack of supply by providing a control circuit of a rolled sheet feeder, which comprises a reversible counter adapted to add and subtract according to a clock pulse and a detection signal. CONSTITUTION:A control circuit of a sheet feeder is adapted to control the height of the lower end of a slackening portion of a rolled sheet. The control circuit comprises an AND gate 10, a frequency division circuit 12, a reversible counter 14 and an AND gate 16. The reversible counter 14 is adapted to perform forward counting by outer of a photo detector 6b and a clock pulse phi, and when the photo detector 6b is turned off, the clock pulse phi is down-counted. When the value of the counter 14 is zero, a let-out motor 3 is stopped, and driven except the value is zero. Accordingly, even if the photo detector 6b is turned off, let-out operation is performed for the time corresponding to the let-out speed to keep a fixed amount of slackening, whereby the sheet can be prevented from contamination, deformation and lack of supply.
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