Canon Kabushiki Kaisha

Junichi Kishimoto

Toshio Hayashi

Noriaki Matsui

Katsuhiro Ishido

Nobuo Matsuoka

Satoru Kijima

An optical scanning apparatus includes a plurality of light sources capable of emitting light. A detection unit detects a light quantity of the light emitted from the plurality of light sources. A control unit controls drive current of a light source designated as a control object based on a detection result obtained by the detection unit. The control unit controls the drive current based on an activation state of the light source designated as the control object and an activation state of a light source other than the control object.

Optical scanning apparatus

In an image reading apparatus having a light source for illuminating a document, an image sensing element for outputting an electrical signal in accordance with an input light quantity, a first reference member, and a second reference member, shading correction data is acquired. A time since the light source is turned on is measured, and when the measured time does not reach a predetermined time, shading correction data is acquired by a first method using the first reference member. When the predetermined time has elapsed, shading correction data is acquired by a second method using the second reference member.

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Kashiwa, Japan

Junichi Kishimoto