| 摘要 |
PURPOSE:To accurately detect an adhering toner quantity by calculating an adhering half-tone testing toner quantity based on the measured value of the quantity of light reflected on the basic surface of an electrostatic latent image carrier, a measured value of the quantity of light reflected on a saturation level testing toner image and the measured value of the quantity of light reflected on a half-tone testing toner image, and also controlling an image forming condition based on the calculation value. CONSTITUTION:A sensor output voltage Vs0 at the basic surface level of a photosensi tive body is measured. The saturation level testing toner image is formed, and then, the quantity of the light reflected on the saturation level testing toner image is mea sured by the sensor 15 so as to obtain the output voltage Vs2. When a basic surface level measuring point on the photosensitive drum 1 reaches a toner image forming position C1 again, the half-tone testing toner image is formed while impressing a developing bias voltage Vb1. The quantity of the light reflected on the half-tone testing toner image is measured by the sensor 15, and then, the output voltage Vs1 is obtained. Vs1 - Vs0/Vs2 - Vs0 is calculated every color toner, and the adhering toner quantity which is obtained when the developing bias voltage Vb1 is impressed is obtained. Then, the developing bias voltage Vb of every color toner is calculated. |
