| 摘要 |
PURPOSE:To prevent heat generating elements from overheating, by setting two periods respectively on a first timer and a second timer, and taking a predetermined rest period before driving the heat generating elements in the period set on the second timer. CONSTITUTION:With a power source switched ON, various registers are reset, and a first timer TM1 is started, under an initialization program stored in a ROM 2. When a predetermined time t1 is counted, it is checked whether the value in a P register is not more than '0', namely, whether the sum total P of thermal outputs is in excess of an allowable thermal output P1. When P<=0, the P register is reset, the timer TM1 is restarted, and when the predetermined time t1 is counted, the same processing as above is performed. When the value in the P register exceeds P1, P>0, and a timer TM2 is started. A predetermined rest period is taken before driving heat generating elements in a period set on the timer TM2. When the period set on the timer TM2 runs out, it is discriminated whether the sum total of thermal outputs is in excess of a second predetermined amount P2. When the sum total of the thermal outputs is not more than the amount P2, the timer TM1 is started, whereas when the sum total is more than the amount P2, the timer TM2 is restarted. |
