Abstract: In a printer, a sheet feeder includes a motor which is used for a plurality of mechanisms in common so as to make the printer lighter in weight and more compact in size. The sheet feeder can vary the feeding amount of the sheet in response to the printing operation. The sheet feeder also permits the manual operation of a sheet feed roller shaft by disconnecting power from a motor via a power switching mechanism. The power switching mechanism includes a clutch mechanism which has a gear for transmitting the power of the motor, and a clutch wheel. The clutch mechanism is used when feeding the sheet by the operation of the motor. The sheet feeding amount is varied by the operation of a partial gear which comes into contact selectively with a first or second feed cam. These feed cams have projections having different heights.

Abstract: A sheet conveying device provided with a detent mechanism and capable of effecting automatic feeding of the shet by the use of a drive source and also capable of effecting feeding of the sheet by manual operation, the sheet conveying device including a rotational member for conveying a sheet, a drive source for driving the rotational member, a drive transmitting device for transmitting the drive force of the drive source to the rotational member to rotate the rotational member by the drive force of the drive source, a manual operating member for manually driving the rotational member, a detent device producing a rotation restraining force, a restraining force transmitting device for transmitting the restraining force from the detent device, and apparatus for connecting and disconnecting the restraining force transmitting device and the drive transmitting device.