International Business Machines Corporation

Charles David Malkemes

Barry R Cavill

Kevin Michael Reinberg

William L Zipoy

Timothy Jackson

Raymond A Schultz

A wire fire control mechanism is provided for use in a wire matrix printer for controlling the firing of the print wires as the printhead moves across a print receiving medium. This wire fire control mechanism enables printing to be accomplished for a wide range of different printhead speeds. It also enables printing to be accomplished while the printhead is accelerating or decelerating. It further enables dots to be printed at positions which are not dependent on or limited to the fixed points defined by the emitter signals which are used to keep track of the position of the printhead as it moves across the print receiving medium. In a representative embodiment, the wire fire control mechanism includes emitter means for sensing movement of the printhead and producing emitter signals which define fixed points across the print receiving medium. The control mechanism also includes means for providing a target signal for determining a position at which a dot may be printed on the print receiving medium, such dot position not being dependent upon or limited to the fixed points defined by the emitter signals. The control mechanism further includes means for sensing the speed of the printhead and producing a flight time distance signal representing the distance the printhead will move while a print wire is in flight from the printhead to the print receiving medium. The control mechanism further includes means responsive to the target signal, the emitter signals and the flight time distance signal for producing a wire fire signal when the distance between the print wire position and the target becomes substantially equal to the flight time distance.

Wire fire control mechanism for a wire matrix printer

A control system for a printer having a print head bidirectionally movable at speeds selected from either a first group of speeds or a second group of speeds which employs a microcomputer to generate a digital signal representing the percentage of time a preselected voltage level should be applied to drive the motor which controls the print head speed. The motor includes an integral dual channel incremental optical encoder which generates a pulse each time an emitter is detected, the pulse being directed back to the microcomputer as measured speed information. The microcomputer compares the measured speed information with the desired speed information during predetermined time intervals and if they differ changes the value of the digital signal by an equal amount for each time interval until the desired speed is obtained or until a different print head speed is desired. A different method is used to determine both the measured speed information and the desired speed information depending on whether the desired speed falls within the first or second group of speeds.

Print head motor control system having steady state velocity compensation

There is disclosed herein printer control logic for controlling a matrix printer. The control logic includes an interruptable microprocessor, together with associated memory. Additionally the control logic includes a programmable timer which provides a signal a determined time after being programmed. The control logic responds to print emitter signals manifesting an incremental movement of the print head by interrupting the microprocessor. The microprocessor then programs the timer to provide signals after a programmed delay time to again interrupt the microprocessor. The microprocessor then provides signals causing the operation of the print elements on print head.

Printer control logic

A system for processing data incorporates a central processing unit and a microprocessor serving as a controller together with associated logic for controlling operation of an attached device such as a serial or line printer. Data is transferred from the microprocessor to the printer by a cable having a number of wires, reduced in number from the number required if printer is directly attached, and involving a multiplexed data transfer operation with storage latches provided in the printer for storing character image information and printer function information. Increased reliability is realized by a repeat cycle operation of the microprocessor wherein significant image or function information is sent to the printer in a succession of repetitive cycles, thus insuring accurate operation of the relatively slow magnets and driving elements in the printer.

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Boca Raton, FL, United States of America

Charles David Malkemes