International Business Machines Corporation

Louis V Galetto

James M Rakes

Johann Hans Meier

Donald Frederick Jensen

Charles O Ross

Robert W Arnold

Bruce Allen Wolfe

Walter Thornton Pimbley

Apparatus for recording a displayed frame of video data by storing the binary data bits from identical segments of each video scan line, thereafter supplying the stored bits of the segments to a traversing matrix print head for recording the bits in those segments, and repeating the process with data bits from a different series of scan line segments. The number of data bits comprising a segment usually corresponds to the number of recording elements in the print head, and the number of print head excursions will vary inversely to the number of data bits in each segment. A resulting recorded video frame thus appears rotated 90.degree. with respect to the original frame orientation.

Apparatus for recording displayed video data

A current shunt multiplexed driver circuit in a high resolution multi-wire printhead is provided for use in an electroerosion printer. The circuit can reduce to the number of active devices required per print wire to two times the square root of the number of wires.

Controlling a multi-wire printhead

A pulse width modulated DC motor control system is designed to operate a DC motor at constant velocity. Feedback pulses generated at a rate proportional to the rotational velocity of the motor are converted to control pulses having a fixed on-time period which is independent of changes in the velocity of the motor. The control pulses are used to modulate a constant current source whose output is integrated to generate a sawtooth voltage signal whose average DC value is used as the basis of or pulse width modulating a DC voltage applied to the motor drive circuits of a DC motor.

Analog DC motor velocity control loop

In a magnetic ink jet printer a continuous stream of ferrofluid ink drops is projected toward a print medium. A magnetic selector located proximate the stream is operated in synchronism with the flight of the ink drops for deflecting individual unwanted ink drops into a drop catcher. Due to fringing effects produced by the selector when unwanted drops are selected, adjacent print drops are deflected a lesser amount from the initial stream trajectory. Print drops not affected by the fringe magnetic field produced to select unwanted drops are subjected to a compensation deflection depending on their position relative to the unwanted drops so that all print drops follow the same trajectory, after passing the magnetic selector in their travel through a vertical deflector and deposition onto the print medium.

Ink jet printer apparatus and method of operation

A dot matrix printer apparatus has a magnetic ink jet recording head which projects a continuous stream of ferro-fluid ink drops toward a print medium. The ink drops are rastered in the direction orthogonal to the direction of relative motion of the recording head and the print medium to form characters from columns of dots. The slant of the characters caused by the change in direction of relative motion is controlled by reversing the direction or sequence of rastering of ink drops when the direction of printing reverses.

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Endicott, NY, United States of America

Louis V Galetto