| 摘要 |
PROBLEM TO BE SOLVED: To provide a protection circuit against an overcurrent in the scanner of an image formation device which can surely perform a drive element protec tion motion, with the detection of an overcurrent over a certain time, performing an overcurrent detecting action without using a microcomputer. SOLUTION: An image formation device, which reciprocates a scanner with a motor, has an H-type bridge circuit which rotates the motor normally or reversely, a microcomputer which performs the detection of the rotational speed of the motor, the speed operation, and the speed control by the detection signal of an encoder, a motor current value detector, and two comparison means IC51 and IC52 which compares the motor current value with the preset two protective current values. When it is judged that an overcurrent is flowing to the motor by the first comparison means IC51, this protection circuit performs limit of the overcurrent. When the overcurrent is detected with the first comparison means, and it is judged that the condition that the overcurrent is flowing has continued for a specified time by the second comparison means, it stops the motor control. |
