| 摘要 |
PURPOSE:To record intermediate gradation by using a CRT as a light source for forming electrostatic latent image and controlling the size of spot on the CRT in response to the gradation level of a picture signal. CONSTITUTION:After a photosensitivity drum 1 is charged uniformly, a light pattern by the CRT3 is irradiated to form the image of the light pattern on the photosensitive drum 1 thereby forming the electrostatic latent image. Then a desired recording picture is obtained by the successive process of development/ transfer/copy. The area of the spot on a fluorescent plane 22 of the CRT3 is controlled in response to the gradation level of the picture signal to obtain an intermediate gradation recording picture by dots. Thus, a voltage applied to an electrode having a function focusing an electron ray of an electron gun 20 is controlled in response to a level of the picture signal so as to control the focus from the just focus to a slight out-focus where the spot has a prescribed spread, and the intensity of the electron beam is controlled properly to make preferably the brightness in the spot constant.
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