| 摘要 |
PURPOSE:To replenish toner into the developing device of a color copying machine, etc., with high accuracy. CONSTITUTION:A two-component developer composed of toner and a carrier is housed in the developing device. The decrease of a mixing ratio (toner/ developer) caused by the consumption of the toner in the developer in the developing device following development is prevented in such a manner that the toner is successively replenished into the developing device by a developer replenishing device. The replenishment is executed according to image data as follows. The image data is binarized by a binary circuit 73 in the main scanning and subscanning directios of the image data and counted to obtain the ratio of the number of image edges (spatial frequency) per unit area in the longitudinal direction to that in the lateral direction decide the type of an image by a feature extracting circuit 74. A deciding circuit 75 attains comparison with a known data to estimate the consumption of the toner and determine an exact quantity of the toner replenished to the developing device, according to the decision. |
