Abstract: In a dot-matrix printer including a wire-dot print head having print wires which print dots by impact on a printing medium, and a sensor for sensing the position of the print wires and generating signals indicating the position of the print wires, a parameter is set to determine a printing force with which each of the print wires impacts the printing medium. A control and driving circuit drives the print wire responsive to the signals from the sensors and the set parameter. The combination of the feature of setting a parameter for controlling the printing force and the feature of detecting the position of the print wire enables the control over printing force with a high reproducibility. So printing with an optimum printing force is ensured.

Abstract: A wire-dot impact printer includes a wire-dot print head having a plurality of print wires disposed therein. Each of the plurality of print wires has a distal end, and each is displaced in response to a drive signal so as to strike a printing medium with the distal end. A displacement detecting device is provided for detecting a displacement resulting from the drive signal of each of the plurality of print wires and for outputting a corresponding displacement detection signal. A control unit, which controls the overall printing operation of the impact printer, varies the print repetitive cycle of each of the plurality of print wires in accordance with the displacement detection signal outputted by the displacement detecting unit.

Abstract: A driving apparatus for a wire-dot print head in a wire-dot impact printer has a sensor mounted in the print head to detect the motion of the print wires, enabling each print wire to be driven for the optimum time for each dot. Beneficial results include improved print quality, reduced power consumption and operating temperature, and faster printing.

Abstract: In a printer in which a printing medium is moved by a line-feed stepping motor during line-feed operation, and the line-feed stepping motor is stopped during printing operation and in a ready state, the line-feed stepping motor is caused to generate a first holding torque for preventing unwanted movement of the printing medium while permitting the operator to feed the printing medium manually, in the ready state of the printer, and the line-feed stepping motor is caused to generate a second holding torque which is greater than the first holding torque, during the printing operation.