SHEET FEEDER, IMAGE FORMING APPARATUS INCORPORATING THE SHEET FEEDER, AND IMAGE FORMING SYSTEM INCORPORATING THE SHEET FEEDER

摘要

A sheet feeder, which is included in an image forming apparatus and an image forming system, includes a sheet loader on which a sheet bundle is loaded, an air blower to blow air to the sheet bundle loaded on the sheet loader and float upper sheets of the sheet bundle, a loader elevation device to lift and lower the sheet loader, a reflective optical detector including a first reflective optical detector to detect the upper sheets floated by the air blower and a second reflective optical detector to detect multiple floating sheets located below the floating sheets detected by the first reflective optical detector, and a controller configured to control the loader elevation device to perform a lifting operation of the sheet loader based on a combination of an output value of the first reflective optical detector and an output value of the second reflective optical detector.