International Business Machines Corporation

Lexmark International, Inc.

Clifford M Denny

Johnnie A Coffey

Donald Lee West

Hugh T Findlay

Selahattin A Okcuoglu

Deh C Tao

John P Bradley

Thomas H Williams

Stephen A Popyach

John G Hughes

Charles W Wampler, Ii

Hugh E Naylor, Iii

A dot matrix printhead is adjusted automatically or manually with respect to a platen in accordance with the thickness of a recording medium on which printing is to occur. When a host data processor sends a control signal to a printer microprocessor to indicate that a recording medium of a different thickness is to be printed, a carrier, which has a first portion supporting the printhead and pivotally and slidably mounted on a front guide rail, is moved so that a shift arm on the carrier engages a right side plate of the frame. This disconnects a ribbon drive motor gear from a ribbon drive gear and moves the ribbon drive motor gear into engagement with a gear train. Rotation of the gear train rotates a gear, which has a threaded shaft and is rotatably supported by a second portion of the carrier slidably mounted on a rear guide rail, to cause pivoting of the first portion of the carrier about the front guide rail to change the gap of the printhead from the platen. When the gap change is completed, the carrier is moved to the left to its recording medium loading printing position and to disengage the ribbon drive motor gear from the gear train and reengage it with the ribbon drive gear. Then, manual adjustment of the spacing of the printhead from the platen may be accomplished.

Printer having printhead gap adjustment mechanism

Roller 1 is heated to a temperature at which correctable thermal printing is caused to be better fixed to the paper and to be darker, while lift-off correction may be subsequently conducted. Roller 1 is spaced from printhead 3 a distance sufficient to permit reading of immediately prior typing. Both roller 1 and printhead 3 are mounted on carrier 5.

Modified thermal printing using a heated roller and with lift-off

Disclosed is drive apparatus especially useful for controllably displacing the carrier of a printer, the drive apparatus including a lead screw having laterally spaced apart and floating threaded followers thereon. Intermediate the threaded followers are a first pair of preloaded springs which press the followers against the opposite flanks of the threads on the lead screw to thereby inhibit backlash intermediate the followers. A second pair of springs are mounted intermediate a bracket, which is fastened to the carrier, and at least one of the followers for effecting coupling between the carrier and the follower while controlling backlash therebetween. A pair of arms extend from the followers and are coupled to a restraining shaft in such a manner as to inhibit rotational movement of the arms (and thus the followers) while permitting motion of the followers in any perpendicular direction to the lead screw to accommodate runout or eccentricity.

Backlash and runout compensator for lead screw drives

In a continuous type ink jet printer having a conventional charging electrode for charging ink drops in accordance with a signal to be recorded on a record receiving media, a pair of deflection electrodes is mounted in a rocker which pivots on a holder mounted on the carrier. As the carrier is accelerated from the stop condition to print speed, the acceleration of the carrier effects rotation of the rocker about the pivot and thus automatic tilt of the deflection electrodes backward from the direction of carrier movement thereby tilting or inclining the electric field formed between the electrodes to compensate for carrier movement. In the preferred form, a simple magnetic type latch is applied to retain the rocker in one position for printing in a first direction, and to enable quick release and reversal, under inertial control, when the carrier moves in the opposite direction.

Inertial deflection field tilting for bi-directional printing in ink jet

Techniques are described for producing superscripts (half indexing), subscripts, and character height reduction for an ink jet printer.

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Lexington, KY, United States of America

Clifford M Denny