Sheet supply apparatus

摘要

The present invention provides a sheet supply apparatus comprising a lifter device for maintaining a height of an upper surface of a sheet stack supported by a sheet supporting device substantially constant by lifting or lowering the sheet supporting device, and a supply device for feeding out an uppermost sheet from the sheet stack maintained in a constant height position by the lifter device, and wherein the lifter device comprises a clutch member for transmitting a predetermined amount of rotation from a drive gear, a rock member for rocking a ratchet pawl by the rotation transmitted by the clutch member, a ratchet gear engageable by the ratchet pawl and rotated by a rocking movement of the ratchet pawl, a lifter member connected to the ratchet gear and adapted to lift the sheet supporting member by rotation of the ratchet gear, and an actuation device shifted in accordance with the height of the upper surface of the sheet stack rested on the sheet supporting device and adapted to actuate the clutch member when the height of the upper surface of the sheet stack is below a predetermined height.