Abstract: The present invention, whose auto sheet feeder is demountably mounted on a printing machine, which includes a sequential arrangement of a reversible motor, a transmission mechanism, and a rotatable platen, is provided with an input gear, an arm whose one end is supported by the input gear for rotation around its axis of rotation and is urged to move toward a gear of the transmission mechanism, and as planetary gear rotatably provided at the end of the arm to be constantly in mesh with the input gear and opposite to the periphery of the gear of the transmission mechanism.

Abstract: The invention provides a paper feed device for a printer which comprises a pin feed mechanism mounted for changing over movement between a pushing position and a drawing position, a guide plate for guiding sprocket paper to a platen from a position rearwardly of the pin feed mechanism in the pushing position, a pinch roller mounted on the guide plate for movement toward and away from the platen, a movable guide plate for guiding a cut sheet from between a front face of the pin feed mechanism and the platen to a contact point between the platen and the pinch roller, a pair of arms pivotally supported at opposite side ends of the movable guide plate, and supporting means located on opposite sides of the pin feed mechanism, the supporting means retracting the movable guide plate upwardly when the pin feed mechanism is changed over to the drawing position.

Abstract: A printer includes a carriage, a printing head, a platen, a cartridge holder for removably holding a cartridge accommodating a multi-colored ink ribbon which is rockably mounted on the carriage so as to be able to move the multi-colored ink ribbon in the width direction relative to the printing head, and a ribbon-position switching device for driving the cartridge holder to bring a desired color zone on the multi-colored ink ribbon to a position corresponding to an end of the printing head for using the desired color zone.