| 摘要 |
PROBLEM TO BE SOLVED: To correct a reference voltage for deciding automatic original density wherever the number of plural sheets reaches the fixed number of sheets by detecting the reference voltage for deciding the automatic original density by the detection signal of a light quantity detecting means. SOLUTION: The light quantity detecting means 37 for detecting the light quantity of an exposure lamp 16 is arranged at the defocused position near an exposure optical system. When a scanner unit including a 1st scanner and a 2nd scanner lies at a stoppage position on a home position side, a reference white board is positioned just above a 1st mirror 17, and then, light reflected by the reference white board is made incident on the light quantity detecting means 37 through the 1st, 2nd and 3rd mirrors 17, 18 and 19, then, the light quantity of the exposure lamp 16 is sensed. And the detection signal obtained when the light reflected by the reference white board is detected by the light quantity detecting means 37 is inputted to a reference voltage detecting means, and the reference voltage for deciding the automatic original density is detected by the detection signal. |
