| 摘要 |
PROBLEM TO BE SOLVED: To provide a printer capable of providing an optimum image for every high and low resolution and suppressing time loss and image change caused by switching the processing speed corresponding to the resolution. SOLUTION: The printer adopting a two-components developing system, where the resolution is switched in accordance with the switching of the linear velocity of a developer carrier and a photoreceptor drum, is equipped with a toner concentration sensor for outputting a voltage value by detecting the toner concentration of the developer carrier at the time of switching the resolution. Threshold voltage in accordance with the image resolution respectively represented by the voltage value of the toner concentration outputted by the toner concentration sensor is changed based on the relation of the image density to the toner concentration so as to properly judge whether the replenishment of the toner is required or not. |
