Patent ID: 7242416

Claim:
A control device for an optical head, which successively lights in a sub-scanning direction the respective light emitting elements of a light emitting element matrix in which a plurality of light emitting element groups arranged in the sub-scanning direction are further arranged in a main scanning direction, and subjects each of the plurality of pixels disposed in the main scanning direction to multiple exposure, comprising: a storage unit for receiving pixel data for each pixel and storing data corresponding to the plurality of pixels disposed in the main scanning direction; a shift register group consisting of a plurality of shift registers respectively corresponding to the plurality of pixels disposed in the main scanning direction, each shift register having a plurality of registers respectively corresponding to the light emitting element groups arranged in the sub-scanning direction, each shift register receiving the data for each pixel stored in the storage unit, and said shift register group successively shifting the data of each register within the shift register; and an element drive circuit for lighting the corresponding light emitting elements on the basis of the data in each register of the shift register, wherein the light emitting elements are driven by the element drive circuit that relays the light emission state from the receipt of a light emission start signal until the receipt of a light emission end signal, and the light emission start signal and the light emission end signal for the element drive circuit of each light emitting element are each transmitted by a time division signal, wherein the element drive circuit is equipped with a plurality of first signal lines and with second signal lines that intersect with the first signal lines, and is constituted such that the light emission of the light emitting elements located at the intersections between two signal lines is started and ended by switching the second signal lines on or off when the first signal lines are active, and the start and end of the light emission of the respective light emitting elements are controlled by synchronizing the on/off state of the second signal lines with the active signal output to the first signal lines, and shifting the active signal output time to the first signal lines for another element drive circuit that shares the second signal lines.