Printer ribbon drive apparatus

Abstract

A hammer is movable to strike paper against a rotatable type member through a ribbon for printing. The hammer is moved for printing by a rotary shaft formed with a projection which engages with the hammer upon rotation of the shaft. A rockable ribbon guide holds the ribbon which has upper and lower portions provided with different colors of ink. A setting lever is pivotally connected to the ribbon guide in such a manner that rocking movement of the setting lever produces rocking movement of the ribbon guide. The setting lever is formed with two engaging portions with which latch members of two solenoids are respectively engagable. A spring urges the setting lever toward a reset position. A first one of the solenoid latch members is arranged to hold the setting lever in a first set position at which one of the colors on the ribbon is in a printing position. Actuation of this first solenoid releases the setting lever so that it is moved by the spring to a second set position at which it is held by a second of the solenoid latch members, the other color of the ribbon being in the printing position. Actuation of this second solenoid releases the setting lever so that it is moved by the spring to the reset position. The projection of the shaft is engagable with the setting lever in the reset position to return the setting lever to the first set position. A ribbon drive shaft is integral with a ratchet, a pawl being reciprocatable to advance the ratchet. A cam fixed to the type member reciprocates the pawl through a rocker linkage to advance the ribbon upon rotation of the type member.

Dependencies are inferred from the claim text.