Abstract: A pulley for connecting a driven device, that is sensitive to speed variations, to be driven by an a.c. motor that is susceptible to speed variations, caused by power line disturbances. The pulley has a peripheral drive surface for a belt drive and two side surfaces through which an opening is formed to receive a drive shaft that is turned by the a.c. motor. One of the sides of the pulley has a slot formed therein with surfaces on each side of the slot. A resilient material of a preselected Durometer value is positioned within the slot and contiguous with at least one of the surfaces in the slot, against which an element projecting from the drive shaft acts to turn the pulley. During a momentary slowdown in the motor speed, the projecting element moves away from the resilient material and permits the momentum of the driven device to maintain its speed while the motor recovers its speed.

Abstract: Circuit for detecting variations in the nominal velocity of a character band and adjusting the hammer firing times to compensate for the variations. This circuit measures deviations in band velocity that are either faster or slower than a nominal velocity during each character emitter pulse and makes an appropriate correction in the subscan times that gate the hammer firing signals. A bidirectional counter is counted up at a high frequency to a value representing the emitter period including the velocity deviation and then counted down after the error determination at a selected frequency that is a preselected fraction of the high frequency. This technique corrects for each character emitter pulse and incorporates a timing proportionality to assure correct hammer impact.

Abstract: A printer having an ink ribbon with a bidirectional ribbon drive in which a pair of stepper motors have their windings cross-coupled so that a drag current flows through one stepper motor to apply drag torque to the ribbon when the other stepper motor is operated for driving.

Abstract: Damper element which absorbs soundwave energy produced in the liquid mass of an ink jet nozzle by a magnetostrictive drop generator is submersed in the liquid mass with or without attachment to the nozzle chamber.