Dainippon Screen Mfg. Co., Ltd.

Hiroshi Tamura

Yasuo Kurusu

Kazuma Kan

An apparatus for and a method of stabilizing the quantity of light of a fluorescent lamp employed for illuminating an original to be duplicated or the like. The quantity of light of a fluorescent lamp reflected by a reference plane is detected, when scanning of an original is started, to control tube current of the fluorescent lamp on the basis of a detection signal, to thereby perform feedback control so that a detected light quantity value reaches a constant value. When the detected light quantity value reaches a prescribed value, the feedback control is released and the detected light quantity value is held to control the tube current of the fluorescent lamp on the basis of the held detected light quantity value. Thus, the tube current of the fluorescent lamp is adjusted to be constant on the basis of the held detected light quantity value during a scanning interval for the original to be duplicated, whereby the quantity of light of the fluorescent lamp is stabilized.

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Hikone, Japan

Hiroshi Tamura