| 摘要 |
PURPOSE:To stably detect toner concentration with accuracy and reliability over a long period by installing an acoustic energy element in a developing part and detecting the toner concentration in developing by the acoustic output of a frequency peculiar to carrier, or toner. CONSTITUTION:The acoustic energy detecting element 16 is installed on the outer surface of a bristle cutting board 7 in a closely contact state in order to detect the toner concentration in developer in a case 3. And a mechanism 17 for detecting and controlling the toner concentration based on an electroacoustic output from the acoustic energy detecting element 16 is installed. The detecting and controlling mechanism 17 is constituted of a discriminating mechanism for taking out the acoustic output of the frequency peculiar to the carrier, or the toner from the electroacoustic output from the acoustic energy detecting element 16, a computing element for comparing the output from the discriminating mechanism with a reference value and outputting a control signal, and a control mechanism for controlling a toner supply motor based on the control signal from the computing element. |
