| 摘要 |
PURPOSE:To supply an optimum developer quantity which is not influenced by a ground color, and also, corresponds to the contents of a video signal, by a simple and inexpensive constitution, by determining the supply quantity of a developer in accordance with the number of white or black dots in the sampled dots. CONSTITUTION:A counter 2 counts the number of dots for taking the black level of an incoming video signal V10, at every one main scanning line, and gives the contents CBU of the high-order 8 bits of its count value to a control part 1 through a buffer circuit 7. The control part 1 estimates the quantity of the developer consumption corresponding to a video signal image, based on the number of black dots CBU related to such one line, and applies a driving signal DR1 to a toner supply device 8 through an input/output device 3, by the time corresponding to the result of estimation. In such a way, when a developing machine 6 executes a developing action, the state of excess or shortage of a toner does not occur. |
