| 摘要 |
PROBLEM TO BE SOLVED: To shorten a stirring time for a developer, for making its electrification stable, when toner whose electrostatic chargeability is low is included by executing a toner consuming operation, at the time of driving a developer stirring means. SOLUTION: The developer and toner in a developer stirring tank is stir- mixed by a stirring roller, during the warm-up just after a device is started and the developing operation, just before and after the developing operation, etc., on purpose to improve the electric charge quantity of the developer reduced in it, in such a manner that the developer and the toner are uniformly mixed. The toner consuming operation of consuming the toner in the developer is executed with this stirring operation. In other words, when a value detected in a white part potential part becomes one larger than a value (m) shown by a short dashed line for three consecutive times, it is judged that the density of the white part potential part becomes stable at a proper value and the developer has a desired electric charge quantity. When the toner consuming operation is executed, the developer has the desired electric charge quantity in a time shorter than that when the toner consuming operation is not executed. |
