Patent ID: 8098271

Claim:
An exposure device comprising: a light output device that outputs light for exposing a charged image carrier, the light output device including: a plurality of light-emitting elements caused to emit light or not to emit light through a control using a light-emission signal; a plurality of switch elements provided respectively corresponding to the plurality of light-emitting elements, the switch elements being sequentially turned on to set the respective light-emitting elements ready to emit light; a transfer signal generating unit that generates a transfer signal for sequentially turning on the plurality of switch elements; a light-emission signal supply unit that supplies the light-emission signal to the plurality of light-emitting elements; and a detection unit that causes the transfer signal generating unit to generate a transfer signal for each failure detection operation, the transfer signal having a plurality of cycles corresponding to transfer periods that detect disconnection in the wiring for the light-emitting elements and also having another cycle after the plurality of cycles corresponding to a transfer period that detects transfer trouble of the switch elements, the total number of cycles of the transfer signal for each failure detection operation being larger than the number of the plurality of light-emitting elements, and that detects an electric potential of an output region of the light-emission signal supply unit while making an output from the light-emission signal supply unit high impedance; and an optical member that focuses light outputted by the light output device onto the image carrier.