| 摘要 |
PURPOSE:To set the quantity of light emitted from all LEDs in an LED array to within an allowable range, by a method wherein a plurality of chips constituting an LED array are provided respectively with constant-current circuits, and constant current setpoints for the circuits are set in accordance with the characteristics of each chip and printing information. CONSTITUTION:A plurality (e.g., 16) of chips 1a-1n each of which comprises a plurality (e.g., 128) of LEDs are arranged to constitute the LED array 1, and each of the LEDs is selectively driven by a matrix driving circuit 2 in accordance with the printing information S. In this exposure light source, the constant- current circuits 3a-3n and current-setting circuits 4a-4n are provided between the driving circuit 2 and each of the chips 1a-1n, and the constant current setpoints for the circuits 3a-3n are set by the current-setting circuits 4a-4n in accordance with the characteristics of each of the chips 1a-1n and the printing information. |
