| 摘要 |
A power supply supplies an a-c power as primary electric power and a d-c power as secondary electric power. A converter converts the primary electric power, for example, 100 VAC into the secondary electric power, for example, +5 VDC and +24 VDC. The primary electric power is used to heat, for example, a heat roller of a printer. An abnormal-temperature detector outputs a detection signal when the temperature of the heat roller heated by the primary electric power exceeds a predetermined temperature. A controller causes the converter to draw an additional current from the primary electric power in response to the detection signal so that a current drawn from the primary electric power exceeds a predetermined current. An abnormal current interrupter shuts down the current drawn from the primary electric power when the current drawn from the primary electric power exceeds the predetermined current. The power supply may have an abnormal current detector instead of the abnormal-temperature detector. The abnormal current detector outputs a detection signal when a current supplied to the heat roller continues to flow longer than a predetermined period, and outputs a detection signal. The controller causes the converter to draw an additional current from the primary electric power in response to the detection signal so that a current drawn from the primary electric power exceeds a predetermined current.
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