| 摘要 |
PURPOSE:To make a titled device adaptive to a partial change in the density of an original and to shorten the time for starting image formation by controlling the value of bias for development with the density values of the original detected in plural regions. CONSTITUTION:When a copying start button is pushed, the 1st mirror 104 and the 2nd and 3rd mirrors 105 scan an original 101 at a speed ratio of 2:1. A means 107 for detecting the quantity of light samples the quantity of light at every 0.1sec and stores successively the same in an RAM via an A/D converter. The bias for development is determined according to the average value of the sampling data between A-C of the original in the stage of developing the position B of the original at the point (b) in a developing device 110. The sampling data between B-D is similarly used in the stage of starting development of the point C and therefore the bias is controlled by the average data before and behind the point to be developed. Good accuracy is thus obtd. and the device is made adaptive with a partial change in the density of the original. |
