| 摘要 |
PROBLEM TO BE SOLVED: To realize a method for correcting light amount fluctuations and a means which are hardly affected by dirt of a belt in an image reader. SOLUTION: The image reader comprises a means which calculates a gain setting candidate value [G0] by prescribed calculation from an image sensor output level [S0] during reading reflected light with an image sensor 101, when an original manuscript backup member is exposed to light of a lamp in a nonexistent state of an original manuscript at a reading part before reading the original manuscript and an image sensor output level [S1] during reading reflected light with the image sensor 101, when the original manuscript backup member is exposed to the light of the lamp between respective original manuscripts after starting the reading of the original manuscript; a gain setting range calculating means, which calculates an allowable range of a gain setting value by prescribed calculation from the light amount change amount during pre-lighting obtained by a light amount change detecting means and an illuminating time counter value; and a gain setting means which executes limit processing, so that the gain setting value does not exceed the gain setting range and sets the gain setting value [G1] subjected to the limit processing to a gain variable circuit. COPYRIGHT: (C)2005,JPO&NCIPI
|
