| 摘要 |
PROBLEM TO BE SOLVED: To obtain a color image whose image density is constant from initial image-forming and whose quality is high by maintaining the toner density of two-component developer constant even if the change or the like of the developing performance of toner caused by environment fluctuation is caused. SOLUTION: At the image-forming station of each color, toner replenishing quantity for toner replenishment control made by a patch detection ATR is obtained based on the density detection of a patch image by a density sensor 73 so as to make it as correction toner quantity. In the case that developer at the inside of a developing device 44 is the color developer of a chromatic color, the toner replenishment control of a developer reflection ATR based on the density detection of the developer by the density sensor arranged at the inside of the developing device 44, and in the case that it is the black developer of an achromatic color, the toner replenishment control of a video counter ATR based on the arithmetic of required toner quantity from the output level of a digital picture signal for each picture element by a counter 66, are made by respectively correcting by the correction toner quantity. |
