Patent ID: 8659633
Filing Date: 2014-02-25
Classification: B41J,H05B

Abstract:
1. A light source control apparatus comprising: a light source configured to output a light beam of which light amount depends on supplied driving current, wherein a current-light characteristic of the light source includes an uptrend region where the light amount increases with increasing driving current and a downtrend region that touches the uptrend region at a peak value of the light amount and where the light amount decreases with increasing driving current; a light variation detection unit configured to detect variation of the light amount of the light beam outputted from the light source and to output a light variation detection signal; a current variation detection unit configured to detect variation of the driving current and to output a current variation detection signal; a determination unit configured to determine whether the light source is operating in the uptrend region or in the downtrend region based on the light variation detection signal and the current variation detection signal; and a control unit configured to control the driving current so as to match the light amount of the light beam with predetermined target light amount, by increasing the driving current when said determination unit determines that the light source is operating in the uptrend region and when the light amount of light beam is less than the target light amount or when said determination unit determines that the light source is operating in the downtrend region and when the light amount of light beam exceeds the target light amount, and by decreasing the driving current when said determination unit determines that the light source is operating in the uptrend region and when the light amount of light beam exceeds the target light amount or when said determination unit determines that the light source is operating in the downtrend region and when the light amount of light beam is less than the target light amount.