Abstract: 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.

Abstract: A rotatable print disk is mounted on a carrier which traverses along the print line. The disk is moved from each character position to the next by the shortest distance and it is stopped at the time of printing. The carrier is moved from one print position to the next at a speed which is selected depending on the time required for the disk to rotate to the next character. Printing takes place with the carrier moving at one of a number of speeds. Hammer firing is timed dependent on printing speed.

Abstract: Adaptive control circuit for a stepping motor in which each motor displacement from a present position to a target position is monitored and the proportion of acceleration signals to deceleration signals is modified as necessary to obtain minimal elapsed time during motor movement. Each designated motor displacement is assigned a corresponding number of acceleration signals which are applied to move the motor. Then during a subsequent homing of the motor, the motor displacement is monitored and the number of acceleration signals previously applied is either altered or left unchanged as a result of comparison between this displacement and a standard. The adaptive control circuit is shown as applied to printing apparatus in which a print disk is variously rotated by a first stepping motor mounted on a carrier and the carrier is moved along a print line by a second stepping motor.

Abstract: A serial matrix printer has a print head mounted to move along a print line. The print head has means to change the relative vertical positions of some of the print wires with respect to the others. A first embodiment uses a pair of wire guides arranged so that one is translatable with respect to the other, thereby altering the relationship of the wires in the one guide with respect to the other, and a second embodiment employs a rotatable guide which positions the wires at angles such that the desired spatial relation between the wires is obtained.