| 摘要 |
PURPOSE:To miniaturize a developing device using a two-component developer and to facilitate handling it similarly to the one-component developer system by varying the bias voltage, with which a toner is supplied to a magnetic brush, in accordance with the quantity of a recovered toner. CONSTITUTION:The developing device is so constituted that a magnetic brush 14 is formed on the surface of a cylindrical sleeve 12 by the magnetic force of magnet 13, and developing bias voltages having the same polarity are applied to the cylindrical sleeve 12 and a photosensitive drum 11 from a power supply circuit 15. The magnetic brush 14 on the cylindrical sleeve 12 is brought into contact with the photosensitive drum 11, on which an electrostatic latent image 16 is formed, while moving and gives the toner to the electrostatic latent image 16 to form a developed image 17. In this case, a controller 28 detects the quantity of the recovered toner and controls the voltage so that the bias voltage outputted from a power supply circuit 27 for toner supply is varied in accordance with the quantity of the recovered toner. |
