公开(公告)号：CA1222411A

公开(公告)日：1987-06-02

申请号：CA462551

申请日：1984-09-06

Applicant: IBM

Inventor： BARTLETT JOHN C ,  BOHNHOFF ALAN E ,  CROLEY DONALD F ,  DYER STANLEY ,  EDDS KENNETH E ,  HORLANDER FRANK J ,  STAFFORD DONALD W

IPC: B41J2/325 ,  B41J29/36 ,  B41J29/373 ,  B41M5/26

Abstract: DRIVE FOR THERMAL PRINTING LIFT-OFF CORRECTION Ribbon (22) in thermal printing has an outer layer which adheres to printed characters at intermediate temperatures, lower than printing temperatures. The printhead (7) has a column of electrodes (9) which sweep across the character area. Lift-off is accomplished by the pattern control (40) controlling the current source (38) to provide rapid, square wave pulses displaced in phase 180 degrees at adjoining electrodes (9). The high level of the pulses is about that of the level at printing, and the pulses are sufficiently rapid so that their net effect is to raise the outer layer ribbon (22) to the intermediate temperature. At areas corresponding to underlines of characters, duration of the up period is longer. Good, long term reliability is achieved by the significant erase level being very close to the print level.