| 摘要 |
PURPOSE:To execute a return operation of a scanner at an optimum position at any time, by counting the number of pulse signals generated at every unit extent of movement of the scanner when it advances, and returning the scanner when its counting contents have reaches a prescribed value. CONSTITUTION:When a start command is given, an advancing flip-flop FF1 is set, and by its output, switches SW1, SW2 are opened, a motor 21 is driven, and a scanner runs in the sub-scanning direction from its home position. At the same time, a counter 25 is set, a pulse signal set out from a rotary encoder 24 whenever the scanner runs by a unit distance is counted, and when its counting number becomes equal to a number which has been set in advance by a return position setting device 23, a retrogressing FF2 is set by a coincidence output from a coincidence circuit 26, the advancing FF1 is reset, the motor 21 is driven in reverse, and the scanner executes the return operation. |
