Lexmark International, Inc.

International Business Machines Corporation

John P Bradley

Johnnie A Coffey

David Carl Bishop

Selahattin A Okcuoglu

Clifford M Denny

Joon Won Ha

Printer

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

Disclosed is a drive for a ribbon disc (20) for a printer (10), the printer (10) including a printwheel (12) mounted for rotation on the shaft (15) of a printwheel driver (16) and intermediate a print hammer (18) and print receiving means (40). The printwheel driver (16) is connected to the printwheel (12) for effecting rotation thereto to position predetermined petals (14) of the printwheel (12) opposite the hammer (18). A ribbon disc (20) is interposed intermediate the printwheel (12) and the print receiving means (40) and clutch means (31), in one embodiment, is connected to the shaft (15) for coupling and uncoupling the ribbon disc (20) to and from the printwheel driver (16) dependent upon the direction of rotation of the printwheel (12). In a second embodiment, wherein the printwheel is mounted in a protective cartridge (70), the ribbon disc (20) is also mounted in the cartridge (70) and the known biasing spring is modified slightly to form a clutch (75) to first inhibit the rotation of the ribbon disc (20) when the printwheel (12) rotates and allow the rotation of the ribbon disc (20) when the printwheel (12) rotates in the opposite direction.

Drive mechanism for a ribbon disc

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Versailles, KY, United States of America

John P Bradley