International Business Machines Corporation

Lexmark International, Inc.

Mohsen Marefat

Kevin Dean Schoedinger

Randall David Mayo

Michael Clark Campbell

Donald K Rex

Tuyen Van Pham

Jeffrey H Paterra

Timothy A Green

David Kurt Klaffenbach

A system for automatically adjusting the print head gap of an impact printer, particularly for paper stocks of differing thicknesses and multi-layer forms, provides for measurement of an absolute distance between an undeflected platen position and a home position of the print head. Paper stock thickness is measured by measuring the distance to the home position from a position of the print head when a predetermined force is exerted by the print head against the platen. Since a similar measurement is made when paper stock is not present in the printer and using the same force against the platen, platen flexure is removed as a source of error and a standardized force is available for compression of the paper stock during measurement. Improved accuracy is achieved at high speed while avoiding the use of position encoder/decoder arrangements. A wider range of manufacturing variations in printer geometry and rigidity can be accommodated with uniformly improved print quality.

Platen to print head gap adjustment arrangement

A low-noise, paper pick or other single cycle mechanism is obtained by employing a rotary solenoid (15) which has a force to a detent position which may be overcome by force from a drive roller (1). In the detent position the drive roller faces a blank sector (5) of a gear (3) which is integral with a shaft (7), which is the shaft to be turned. An electrical control signal to the solenoid rotates gear (3) through gear (13), which is directly driven by the solenoid, and which turns gear (11) on the shaft. The drive gear overcomes the force of the solenoid until it is disengaged after one cycle, at which time the detent force of the solenoid holds the mechanism in its detent position.

Quiet, single-cycle mechanism

Growing community of inventors

Lexington, KY, United States of America

Mohsen Marefat