| 摘要 |
PURPOSE:To reduce the toner consumption by arranging a specific number of light quantity sensors at equal intervals in the direction orthogonal to the feeding direction of a transfer material and scanning a picture to operate the inclination of the picture and exposing only a part corresponding to the size of a picture frame determined by this inclination. CONSTITUTION:Three or more light quantity sensors S1-S7 are arranged in a row at equal intervals in print frames 16-1 and 16-2 in the direction orthogonal to the feeding direction of the transfer material to scan right and left a picture 20 projected on a screen. Sensors S1 and S7 output high-level signals and sensors S2-S6 output signals which are switched halfway to the high level and the low level, and these signals are analyzed by a CPU 17 to set the width of an exposure range Wb. Coordinates of positions S2-S6 obtained by fall of signals are operated by the CPU 17 to obtain coordinates of a point D, and a point D' is obtained in accordance with picture positions obtained by rise signals. The length between coordinates D and D' in the (x) direction is a transverse exposure width Wf. Only a part corresponding to the picture area detected in this manner is exposed by a printer to form a picture, thereby reducing unnecessary toner consumption. |
