PURPOSE: To obtain a reversible paper feed mechanism with a small number of parts by providing a planetary gear between a paper feed member mounting on a driving shaft and an internally geared gear that is fixed to the driving shaft.

CONSTITUTION: When a paper feed roller 17 performs ordinary paper feeding as it rotates in the direction as a shaft 10, a spring 18 slackens and the paper feed roller 17 is stationary and the driving shaft idles at the time when a claw 13 meshes with a gear 11. At this time the claw 14 and the gear 12 do not mesh. Motion that urges to eliminate slack in the spring is generated and the paper feeding roller is rotated by one tooth of the complex gear 11 by releasing the claw 13 from the gear 11 by a solenoid 16. In the reverse rotation, electric current is applied to a solenoid 15, and the gear 12 is fixed at a specified position by meshing the claw 14 with the gear 12, and the rotation of a internally geared gear 9 becomes reverse through a planetary gear 20 and it is transmitted to the gear 11. The driving shaft that is rotated in the direction so as to slacken the spring 18 goes into idling and the complex gear 11 stops reverse rotation, and the paper feeding roller also rotates reversely by means of a hook 21.