Print Hammer Control With Rattle Cycle Operation
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
Print hammers in a line printer when not fired for a period of time tend to have a flight time which varies from the design parameter, thereby causing misprinting or misregistration of characters when called upon to print. The problem is prevented by periodically rattling the hammers when not printing. The hammers are rattled by periodic energization with one or more reduced magnitude pulses which cause hammer movement without actually printing. The rattle pulses can be of reduced width and amplitude so that the energy applied to the hammers is enough to overcome the return force of biasing springs and any anomaly forces causing sticking, but insufficient to cause the hammers to impact the type and print medium. As seen in Fig.