| 摘要 |
PURPOSE:To eliminate the influence of drum reverse rotation in the control of paper set to the drum, by outputting pulses during normal rotation of the drum and by counting pulses during reverse rotation and by outputting pulses after counting pulses corresponding to the count value when the drum is changed from reverse rotation to normal rotation. CONSTITUTION:An encoder which can discriminate the drum rotation direction is connected to drum shaft 1a of the copying machine or the like where the paper is wound around the drum and is held automatically. This encoder consists of transparent rotary plate 20a provided with light shield paint at equal intervals of a fixed pitch, transparent plate 20b having slits 21(21A-21C), light emitting diodes PEDs (PED-A-C), and photodiodes PDs(PD-A-C). Rotation direction detecting circuit 30 generates a signal indicating the rotation direction on a basis of output pulses Asig and Bsig of the encoder, and pulse output control circuit 40 outputs timing pulses corresponding to normal rotation obtained by counting and cancelling pulses corresponding to reverse rotation on a basis of the said signal, and thus, positional slippage is not generated in the count value. |
