Patent ID: 7461277

Claim:
An image forming device, comprising: a main control section that controls an operation state of the image forming device and outputs a request for low power consumption to change the operation state from a general operation mode to a low power operation mode; an interface section for controlling external communication with a detection circuit for detecting presence or absence of an external signal supplied to the main control section; a main power supply circuit for supplying power to the main control section only at the operation state under the general operation mode; a power supply control circuit for causing the main power supply circuit to be operated under a low power operation mode in response to the request for low power consumption supplied from the main control section; a low power mode prohibition circuit for outputting a low power mode prohibition signal for voiding the request for low power consumption with respect to the power supply control circuit or the main power supply circuit while the external signal is supplied to the signal detection circuit; and an auxiliary power supply circuit for constantly supplying power to the interface section and the power supply control circuit to allow transition from the low power operation mode to the general operation mode when the external signal is supplied to the signal detection circuit.