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Original scanning apparatus

  • US 5,119,136 A
  • Filed: 12/11/1989
  • Issued: 06/02/1992
  • Est. Priority Date: 12/13/1988
  • Status: Expired due to Fees
First Claim
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1. An original scanning apparatus comprising:

  • a motor;

    a scanning system being reciprocated by said motor to scan an orginial through forward movement thereof;

    pulse generating means for generating encoder pulses corresponding to the rotation of the motor;

    pulse supplying means for supplying drive pulses to apply electric current to the motor, said drive pulse having a fixed but different frequency from that of the encoder pulse when the motor is driven at a constant speed; and

    control means for controlling the speed of the motor in accordance with the on time width of the drive pulse which is supplied by the pulse supplying means, said control means deciding a duty ratio of the drive pulse from the encoder pulse width generated at present and a reference encoder pulse width corresponding to the rotation of the motor when it is driven at a desired speed and supplying the drive pulse to the motor according to the duty ratio desired.

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