Patent ID: 8276906
Filing Date: 2012-10-02
Classification: B65H

Abstract:
1. An image forming device comprising: a main frame; a sheet supply tray assembled to the main frame and configured to hold a stack of sheets; a pressure plate positioned immediately below the stack of sheets when held by the sheet supply tray and movable to a stopping position and to an elevated position for lifting the stack of sheets upward at a sheet supplying timing; a pickup roller positioned above the sheet supply tray and configured to make contact with an uppermost sheet of the sheet stack held by the sheet supply tray for supplying the uppermost sheet, the pickup roller being movable upward and downward in accordance with an amount of sheets in the sheet stack; a planetary gear mechanism including an input gear, an output gear, and a trigger member that is configured to selectively transmit rotation of the input gear to the output gear; a drive source engaged with the input gear and configured to rotate the input gear; a lift mechanism engaged with the output gear and configured to convert rotary motion of the output gear to a force to lift the pressure plate; a cam member rotatably supported to the main frame and having a cam portion; a change-over member pivotally supported to the main frame and pivotally movable, the change-over member comprising a first arm movable between a first position engaging with the trigger member for transmitting rotation of the input gear to the output gear and a second position disengaging from the trigger member for shutting off the transmission of rotation from the input gear to the output gear; and a second arm contactable with the cam portion for moving the first arm between the first position and the second position in accordance with the movement of the pickup roller; a stop assembly pivotally supported to the main frame and pivotally movable independent of pivotal movement of the change-over member and comprising a third arm pivotally movable between a third position engageable with the output gear for stopping rotation thereof and a fourth position disengaging from the output gear for permitting rotation of the output gear; and a fourth arm contactable with the cam portion for moving the third arm between the third position and the fourth position in accordance with the movement of the pickup roller; wherein the cam portion has a cam profile configured to position the first arm at the second position and to position the third arm at the third position when the pressure plate is at the stopping position at a stopping phase of rotation of the cam portion, and to position the first arm at the first position after the start of rotation of the cam portion, and then to position the third arm at the fourth position, and to again position the third arm at the third position while maintaining the first position of the first arm after the temporary rotation stop phase and the rotation re-start phase, and then to position the first arm at the second position.