PURPOSE: To realize a proper copying picture without being influenced by a noise and by making it unnecessary to raise the sampling frequency, by detecting a frequency distribution corresponding to a density of an original, and controlling a copying process condition in accordance with the lowest density and the highest density in that which has its frequency distribution exceeding some frequency.
CONSTITUTION: A spot (a) of an optical beam emitted from an original sheet density detector scans in the diagonal direction a part of an original 19 set on platen glass 1, original sheet density is detected successively, and after the scanning is ended, the spot (a) is hit on a reference density plate 18 and its density is detected continuously. In this way, when density of the original 19 is detected, its original sheet density signal is sent to a data processing part through an amplifier and an A/D converter, a detected data is accumulated successively at each density value in a memory part 23, by which a frequency distribution characteristics of density is obtained. In this regard, by the data processing part, frquency which exceeds some frequency (m) is saturated, the lowest density D1 and the highest density D2 of said frequency (m) are set as ground face density and picture density, respectively, and copying process condition controls such as an exposure quantity control, an development bias control, etc. are executed in the process control part.
| JPS6091370 | IMAGE RECORDING DEVICE |
| JP2009288474 | IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD |
| JPS5670575 | ELECTROPHOTOGRAPHIC COPIER |
YOSHIDA KEIICHI
SAWAKI AKIRA
| JPS5689751A | 1981-07-21 | |||
| JPS55130535A | 1980-10-09 | |||
| JPS543546A | 1979-01-11 |
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