| 摘要 |
PURPOSE:To make the device simpler and lower cost, eliminate measurement errors through equal deposition of the toner on both surfaces of detecting electrodes, and facilitate cleaning of the detection faces, by performing the toner deposition on the detection faces by the use of a commerical AC power source without using any special power source. CONSTITUTION:AC electric fields by a commercial AC power source are generated between transparent detecting faces 11 and 12 by closing SW 19 and developer is supplied between guide plates 1 and 2. When the developer passes between the detecting faces 11 and 12, the toner leaves from carrier and deposits on both of the detection faces 11, 12. The changes in the guantity of light owing to toner deposition are vonverted to photo currents by a light emitting element 15 and a photo detector 16 and the photo currents are sent to a detecting circuit 17. After a fixed time, the capacity of the developer is judged at a detecting circuit by comparing with the reference signal having been beforehand fixed. Upon finishing of measurement, electric fields are generated with the commercial AC power source in cleaning rollers 3, 4 by opening SW 19 and closing 6, so that the toner in the developer from the guide plates 1, 2 is deposited thereon. This developer deficient of the toner is led to the detecting faces 11, 12 to attract the toners having deposited on the detection faces, thereby cleaning the detection faces. |
