| 摘要 |
PROBLEM TO BE SOLVED: To prevent the deterioration of image quality by setting the lowest toner residual quantity in a developing machine at a specific rate to a replenishing quantity of fresh toner when post-transfer residual toner is reused by agitating it with the fresh toner by returning the post-transfer residual toner to the developing machine. SOLUTION: Electric charge is given to a photoreceptor 10 by a primary electrifier 11, and an image is made to appear as a toner image by a developing machine 12, and is transferred to transfer paper P by a transferring separating electrifier 14, and is fixed by a fixing unit 16. After transfer, toner remaining on the photoreceptor 10 is collected by a cleaning unit 20, and is transported to a hopper 30 arranged above the developing machine 12 by an oblique carrying pipe 21. This post-transfer residual toner and fresh toner are agitated in the hopper 30 by a toner agitating part 36, and it is reused. Here, a piezoelectric toner residual quantity sensor arranged in the hopper 30 restricts a toner residual quantity in the hopper 30, and sets the lowest toner residual quantity in the developing machine 12 not less than almost 1/2 to a replenishing quantity of fresh toner. |
