| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of accurately calculating a toner concentration by an optical system toner concentration detecting means even in case where spent occurs on a carrier surface due to stress resulting from use of developer in a developing device using a donor roll. SOLUTION: The image forming apparatus develops an electrostatic latent image on an image forming body by using the developing device accommodating a two-component developer composed of toner and carrier. In the image forming apparatus, a control section calculates the concentration of the toner by measuring an amount of light reflected from the developer in the developing device with the use of an optical sensor. Using the optical sensor, the control section also measures an amount of light reflected from the developer substantially containing only the carrier due to the consumption of almost all the toner in the developer. Based on the amount of light reflected from the carrier, the control section corrects the calculated toner concentration value. COPYRIGHT: (C)2006,JPO&NCIPI |
