| 摘要 |
PURPOSE:To always maintain density and chromaticity of an image constant by controlling value of developing bias voltage of a saturation level test toner image and a test toner image impressed with developing bias of a specified voltage value at the time of image formation, based on each diffused reflected light quantity measured value. CONSTITUTION:A means to form a test toner image where the diffused reflected light quantity is at the level of saturation, a means to form a test toner image while impressing the developing bias of the specified voltage value, and a means 15 which measures the diffused reflected light quantity from the toner adhered to the photosensitive body 1 surface are provided. Then the saturation level test toner image and the test toner image with the developing bias of specified voltage value impressed have their developing bias voltage value at the time of image formation controlled based on each diffused reflected light quantity measured value. Thus, an appropriate developing bias voltage is accurately calculated, the adhering quantity of toner can be maintained constant, and a color image of stable density and chromaticity can be obtained. |
