| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus in which a criterion whether developer can be supplied to a developing means or not can be set for each image forming apparatus and the toner concentration of the developer in the developing means can be stabilized. SOLUTION: The image forming apparatus includes photoreceptor drums 13Y to 13K, developing units 14Y to 14K, a toner concentration detection sensor 47, a shutter member 48, a reflection sheet 81 and a CPU 74. The CPU 74 closes the shutter member 48, receives reflection light from the reflection sheet 81 by means of the reflection signal light receiving element 63 of the toner concentration detection sensor 47, and stores an output voltage V1 in a memory. Subsequently, the CPU 74 opens the shutter member 48, receives reflection light from a developing sleeve 143 by means of the reflection signal receiving element 63 of the toner concentration detection sensor 47, and stores an output voltage V0 in the memory. If an amount Vs of output change per unit toner concentration calculated from V1 and V0 does not fall in a defined range, the operation of the body of the image forming apparatus is stopped. If it falls within the defined range, Vs is stored in the memory. COPYRIGHT: (C)2009,JPO&INPIT |
