Sheet feeder and image forming apparatus

摘要

A sheet feeder includes an air blower adapted to blow air onto an end face of a stacked sheet bundle to thereby float the sheets of the sheet bundle, a conveying section adapted to convey the uppermost floated sheet, a brightness measuring section adapted to measure brightness of light reflected from the end face of the sheet bundle at two or more points in the height direction of the sheet bundle, a determination unit adapted to determine, based on the brightness of each point measured by the brightness measuring section, whether or not the air blowing amount of the air blower is appropriate, and a controller adapted to control the air blowing amount of the air blower based on the determination of the determination unit.

主权项

1. A sheet feeder comprising:
an air blower adapted to blow air onto an end face of a stacked sheet bundle to thereby float the sheets of the sheet bundle; a conveying section adapted to convey the uppermost floated sheet; a brightness measuring section adapted to measure brightness of light reflected from the end face of the sheet bundle at two or more points in the height direction of the sheet bundle, the brightness measuring section including at least two brightness sensors arranged one above the other in a height direction of the sheets of the stacked sheet bundle; a determination unit adapted to determine, based on the brightness of each point measured by the brightness measuring section, whether or not the air blowing amount of the air blower is appropriate; and a controller adapted to control the air blowing amount of the air blower based on the determination of the determination unit, wherein the determination unit determines whether or not the brightness of each point measured by the brightness measuring section is equal to or higher than a predetermined lower limit value and whether or not the brightness of each point measured by the brightness measuring section is within a range defined by the lower limit value and an upper limit value, and determines, if the determination result is positive, that the air blowing amount of the air blower is appropriate.