Patent ID: 8207994

Claim:
A light-emitting device, comprising: a plurality of light-emitting elements that are arrayed in a line at intervals corresponding to a first resolution; a plurality of switch elements that are electrically connected respectively to the plurality of light-emitting elements, and that each set one of the light-emitting elements which is connected thereto to be more ready to emit light when each of the switch elements is set to be in an on state as compared to when each of the switch elements is set to be in an off state; a transfer signal supply unit that supplies a transfer signal for transmitting an on state among the plurality of switch elements by alternately repeating an operation of turning on one switch element in the plurality of switch elements, and an operation of turning on two adjacent switch elements in the plurality of switch elements, the two adjacent switch elements including the one switch element; and a light-emission signal supply unit that supplies a light-emission signal corresponding to a second resolution being a half of the first resolution, at supply timing changed according to whether in a first mode or in a second mode, the first mode being a mode in which an odd-numbered light-emitting element and an even-numbered light-emitting element downstream from and adjacent to the odd-numbered light-emitting element are caused to emit light as a pair, the second mode being a mode in which an even-numbered light-emitting element and an odd-numbered light-emitting element downstream from and adjacent to the even-numbered light-emitting element are caused to emit light as a pair, each odd-numbered light-emitting element being one of the light-emitting elements arrayed at a position corresponding to an odd-number thereof, each even-numbered light-emitting element being one of the light-emitting elements arrayed at a position corresponding to an even-number thereof.