| 摘要 |
PURPOSE:To provide the image recorder having a toner concn. detecting circuit which has the high accuracy of detecting the toner concn. and is low in cost. CONSTITUTION:This image recorder has the toner concn. detecting circuit which detects the toner concn. of a developer by detecting a change in the magnetic permeability of the developer of a two-component system. The above-mentioned toner concn. detecting circuit consists of sensors 51Y, 51M, 51C, 51k for detecting the change in the magnetic permeability, an analog multiplexer 52a, a buffer transistor 52b, a waveform shaper 53, a counter 54 connected to a CPU 50 for control and a gate signal generating circuit 55 connected to the CPU 50 for control which delivers a gate signal to this counter 54. |
