| 摘要 |
<P>PROBLEM TO BE SOLVED: To stabilize image density in an image forming apparatus for forming a toner image and in a toner concentration control device for controlling toner concentration in the image forming apparatus. <P>SOLUTION: The toner concentration control device includes: a concentration sensor for measuring the concentration of toner in a developing unit; an image density measurement section for measuring the density of an image based upon an image signal; and a supply control section for controlling an amount of supply of toner by using a first control system and a second control system, the first control system supplying toner of the amount corresponding to a difference between the toner concentration measured by the concentration sensor and a predetermined target concentration from a toner storage part to a developing unit, and the second control system supplying toner of the amount corresponding to the density of the image measured by the image density measurement section from the toner storage part to the developing unit. In the case where the density of the image measured by the image density measurement section is higher than a predetermined density, the amount of toner supplied by the first control system is made close to zero, and the toner concentration control by the current second control system is prioritized. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
