| 摘要 |
PURPOSE:To accurately detect toner concentration and to eliminate a decrease in the flowability of a developer, and to reduce a load placed on a developing roller by providing a raised wall to a path for the developer which flows correspondingly to the lower part of a toner concentration sensor. CONSTITUTION:The raised wall 12 which is as wide as or slightly wider than the toner concentration sensor 9 is projected at the end part of a guide plate 11 on the side of a doctor blade, and an opening 14 which is linked with an auxiliary guide plate 13 coupled with the lower part of the guide plate 11 is bored in the side part of the raised wall 12. A developer which is scraped off by the doctor blade 8 and passes on the wall surface and guide plate 11 is present by a sufficient amount even under the toner concentration sensor through the operation of the raised wall 12. Then a developer which is to stay is moved from the opening 14 and the side part of the raised wall 12 through the operation of the raised wall 12. Consequently, the toner concentration of the developer is accurately detected, there is no decrease in flowability, and the load placed on the developing roller 4 is reduced.
|
