Donald William Walker

US Patent:

43963080, Aug 2, 1983

Filed:

Aug 13, 1981

Appl. No.:

6/292553

Inventors:

Steven L. Applegate - Lexington KY
James J. Molloy - Lexington KY
Donald A. Walker - Lexington KY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

B41J 2916

US Classification:

400696

Abstract:

In thermal printing the guide (29) positionable toward the platen (3) on a pivoted arm (50) during lift-off correction allows a bond for correction to set before the ribbon (22) is pulled away. The ribbon (22) has an outer layer which adheres to printed characters at somewhat elevated temperatures but is non-tacky at room temperatures. Thermal printing is conducted by setting the switch (44) for heating to temperatures higher than the lift-off temperature.

US Patent:

43753396, Mar 1, 1983

Filed:

Dec 1, 1980

Appl. No.:

6/211886

Inventors:

Stanley Dyer - Lexington KY
James J. Molloy - Lexington KY
Donald A. Walker - Lexington KY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

B41J 3536

US Classification:

400249

Abstract:

A ribbon feed failure in a printer can cause serious problems, particularly for a printer that uses heat to cause selective ink transfers. Localized heat buildup may injure the printhead and, if allowed to continue, might injure other printer instrumentalities. According to the invention, it is recognized that for ribbons having a degree of electrical conductivity, a mechanical ribbon failure will almost always result in a detectable change of electrical properties. By monitoring the characteristics of an electrical circuit passing through a section of the ribbon around the print point and, preferably, also the printhead-ribbon interface, abnormal electrical parameter values that indicate ribbon failure may be detected to trigger a cessation of printer operation. For a presently preferred implementation in a printer that uses a printhead with multiple electrodes for supplying current to a ribbon, the electrode voltage levels for a plurality of non-adjacent electrodes are combined to provide a resultant voltage level that is examined to detect abnormalities. By so combining voltages, insignificant excursions in electrical characteristics as might result from minor ribbon imperfections are generally eliminated from the triggering of a shutdown response, while still retaining a rapid response for preventing further heat generation in those situations where a serious ribbon failure has occurred.