Oscillatory band and hammer dot matrix printer

Abstract

Described, is a printing mechanism allowing full exploitation of the potential of dot matrix printing. Dot forming elements are mounted on a carrier for transport past an array of hammers located in front of media to be marked upon. The dots or carrier are impacted by the hammers to form dots on the medium. By appropriate control of motion of the printing medium and timing of the hammer impacts, a dot may be formed anywhere on the surface of the medium. This allows unlimited character font set generation as well as special character printing for enlarged font, miniaturized font, fast rough draft copy printing, the printing of ascenders and descenders for characters and for condensed or compacted printing. In addition, the mechanism permits an all points available graphics generation system and full control for variable vertical spacing of printed elements and of variable horizontal spacing of the printed elements. Variable print element shapes, grey tone graphics printing and multi-color additive or subtractive color processes are also facilitated. To improve the throughput speed, a reversible motor is used for driving the dot element carrier and a plurality of dot font sizes and shapes are provided on the carrier. By selection of the required font size and shape and by comparison with the presently known position of the carrier, the quickest access to the next desired dot font for any given hammer can be achieved.