Drive for thermal printing lift-off correction

US4545693A · kind A · utility

Assignee

• International Business Machines Corporation · US

Inventors

• John C. Bartlett · Lexington, US
• Alan E. Bohnhoff · Lexington, US
• Donald F. Croley · Georgetown, US
• Stanley Dyer · Lexington, US
• Kenneth E. Edds · Versailles, US
• Frank J. Horlander · Lexington, US
• Donald Wayne Stafford · Georgetown, US

Key dates

• Filing date: Oct 11, 1983
• Grant date: Oct 8, 1985
• Expiry date: Oct 11, 2003

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B41J2/325
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

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.