| 摘要 |
PURPOSE:To eliminate trouble in the case of supplying toner by rotating a developing device and a toner supply mechanism for a fixed time at the time of detecting no-toner and detecting the presence or absence of the toner again. CONSTITUTION:A no-toner detecting sensor 84 consisting of a piezo-elecric element and detecting the presence or absence of the toner T is provided in a toner supply part 74. The sensor 84 is attached to the side wall of the end of a cylindrical guiding part 80 which is positioned just under the opening part 79 of a toner container 76 and mounted so that the circular detection surface 84a thereof may be on an identical surface with the side wall of the end of the guiding part 80. In such a case, the presence or absence of the toner T is detected by utilizing the fact that the oscillating state of the piezo-electric element is different according to whether or not the toner T contacts with the detection surface 84a of the sensor 84. In a state where the on-state of power and interlocking are released. the presence or absence of the toner is detected. In the case of detecting no-toner, the developing device 39 and the toner supply mechanism are rotated for the fixed time and the presence or absence of the toner is detected again. |
