| 摘要 |
PROBLEM TO BE SOLVED: To reduce density unevenness among printing pages without supplying a large amount of toner in a short time, even when a difference between toner density and a toner density target value is increased.SOLUTION: A toner supply control device 100 sets a value higher than a toner density target value by a predetermined density as a first supply control threshold (1), and a value lower than the toner density target value by a predetermined density as a second supply control threshold (2). When a difference between toner density and the toner density target value is larger than a difference between the first or second supply control threshold and the toner density target value, the control device calculates toner consumption on the basis of the number of pixels of an output image, and calculates a toner supply amount by adding or subtracting a predetermined amount to/from the calculated toner consumption (quantitative control method). When a difference between toner density and the toner density target value is equal to or smaller than a difference between the first or second supply control threshold and the toner density target value, the control device calculates a toner supply amount required for making the toner density close to the toner density target value with PID control (PID control method). |
