| 摘要 |
PURPOSE:To execute a toner concentration management control with high reliability and with high accuracy by providing plural developer quantity detecting means in the longitudinal direction of a developer carrying member, and constituting the developer quantity detecting means placed at the opposite side of the development reference side, so as to be movable. CONSTITUTION:In the longitudinal direction of a developing sleeve 11, plural toner concentration detecting members 201, 202 are provided, and the detecting member 201 moves within the width of copying paper by a rotation of a screw-like supporting rod 21 by a prescribed circuit. These two toner concentration detecting members 201, 202 detect alternately a toner concentration at every one sheet of copying paper. Accordingly, in case when copying of a document whose toner consumption is different in between a detecting area of one toner concentration detecting member and the outside of the detecting area is continued, an erroneous detection of the toner concentration detection can be prevented. Also, the toner concentration detecting member 202 is provided so as to always move within the paper width to match the width of the copying paper, therefore, the toner concentration detecting member is always placed in an area having the possibility that a developer is consumed, and a proper toner concentration adapted to the development can always be detected. |
