| 摘要 |
PURPOSE:To stably maintain a specified image density or gradation by providing traveling means capable of setting a screen gap arbitrarily in a screen filter. CONSTITUTION:The traveling means 40 to 42 capable of setting arbitrarily the screen gap in the screen filter 15 are provided. The photosensitive body 9 allows its image density and gradation to change with increase of the number of pieces to be copied, on the other hand, in the screen filter 15, the image density and the gradation can be set by the screen gap. The screen gap 15 can be arbitrarily set by the traveling means 40 to 42. Therefore, the screen gap 15 can be set responding to the change in the photosensitive body 9. Thus, the specified image density and the gradation can be stably maintained. |
