DEVELOPING DEVICE AND IMAGE FORMING APPARATUS PROVIDED WITH SAME

摘要

A developing device includes a development housing, a developer carrier, a toner carrier, a bias applying unit, a leakage detecting unit, a bias control unit and a leakage detection control unit. The developer carrier carries a developer layer. The toner carrier receives the toner from the developer layer and supplies the toner to an image carrier. The bias applying unit includes one transformer and applies direct-current voltages and alternating-current voltages to the developer carrier and the toner carrier. The leakage detecting unit detects leakage occurring between the image carrier and the toner carrier or between the toner carrier and the developer carrier. The leakage detection control unit detects a value of an inter-peak voltage, at which the leakage occurs, by applying the same direct-current voltage to the toner carrier and the developer carrier and changing the inter-peak voltages of the alternating-current voltages.

主权项

1. A developing device, comprising:
a development housing configured to store a developer containing toner to be charged to a predetermined polarity and carrier; a developer carrier configured to receive the developer in the development housing and carry a developer layer by being rotated; a toner carrier configured to receive the toner from the developer layer, carry a toner layer and supply the toner to an image carrier having an electrostatic latent image formed on a surface and carrying a toner image to be developed by the toner by being rotated in a state in contact with the developer layer; a bias applying unit including one transformer and configured to apply direct-current voltages and alternating-current voltages having the same frequency and phases opposite to each other to the developer carrier and the toner carrier; a leakage detecting unit configured to detect leakage occurring between the image carrier and the toner carrier or leakage occurring between the toner carrier and the developer carrier; a bias control unit configured to provide a predetermined potential difference of the direct-current voltage between the toner carrier and the developer carrier and apply the alternating-current voltages so that the toner is transferred from the developer carrier to the toner carrier by controlling the bias applying unit during a developing operation in which the toner is supplied from the toner carrier to the image carrier; and a leakage detection control unit configured to detect a value of an inter-peak voltage, at which the leakage occurs, by applying the same direct-current voltage to the toner carrier and the developer carrier and changing the inter-peak voltages in a state where a ratio of the inter-peak voltages of the alternating-current voltages applied to the toner carrier and the developer carrier is kept constant during a leakage detecting operation different from the developing operation.