Patent ID: 7823874

Claim:
A paper feeder comprising: a sheet tray provided along a guide portion mounted on a main body of an image forming apparatus and capable of being pushed in and pulled out in horizontal directions with respect to the main body; a bottom plate provided inside the sheet tray to be vertically movable; an elevating device for raising the bottom plate as the sheet tray is pushed into the main body and lowering the bottom plate as the sheet tray is pulled out of the main body; the main body having an actuator capable of contacting an upper surface of a sheet placed on the bottom plate as the bottom plate is raised, and a sensor capable of detecting the sheet on the sheet tray based on the actuator contacting the upper surface of the sheet; a through bore or a recess formed in the bottom plate for receiving the actuator when the sheet tray is empty of a sheet, for enabling the sensor to detect that the sheet tray is empty of a sheet; the actuator being oscillatable about an axis extending generally along a pull-out direction of the sheet tray; and a push-out guide provided on peripheries of the through bore or the recess for contacting the actuator lying in the through bore or the recess as the sheet tray is pulled out, thereby pushing the actuator upward out of the through bore or the recess, the push-out guide including an edge portion of peripheries of the through bore or the recess for facing the actuator lying in the through bore or the recess from an upstream side in the pull-out direction, the edge portion being formed in a direction inclined with respect to the pull-out direction and a sheet-feeding direction.