| 摘要 |
PURPOSE: To surely judge discontinuity/continuity by setting the threshold value for judging the discontinuity/continuity in each image forming device. CONSTITUTION: At the time of setting the device main body, or at the time of replacing the exposure lamp 41, before starting the copy operation, the threshold value is set for judging the discontinuity/continuity of the exposure lamp 41. Namely, the slide volume 101 is turned to the dark max. for making the exposure lamp 41 darkest and the exposure lamp 41 is turned on, then the output of the sensor 48 is sampled for plural times with a specified cycle by the zero cross interruption, the average value is calculated, the dark max. voltage VDK as the first light quantity is set, and the exposure lamp 41 is turned off. Moreover, by sampling the output of the sensor 48 several times while holding the exposure lamp 41 turned off, the average value is calculated, and the off voltage VOF as the second light quantity is set. Then, the threshold value VRF as the intermediate value of the both voltage VDK and VOF is set. Thus, the threshold value VRF is set, taking the property of the exposure lamp 41, the sensitivity of the sensor 48, the noise or the like in consideration. |
