Dot matrix printer

DETAILED DESCRIPTION In a preferred embodiment of the present invention, there is provided a dot matrix printer having a row of fixed uniformly spaced cantilevered hammer elements.
The hammer elements alternately have horizontal impactor bars aligned at upper and lower levels in an over-under fashion, and in partial overlapping relation with adjacent impactor bars.
A row of uniformly spaced cantilevered print elements are provided which have upper and lower non-overlapping horizontal impact receiving bars aligned at upper and lower levels, in an over-under fashion, and positioned opposite the hammer elements and which are impacted by corresponding upper and lower level impactor bars on the hammer elements for transverse deflection to form dot impressions on print lines of a print medium.
The print elements have dot producing print elements thereon which face the print medium.
A row of suitable hammer magnets is provided for actuating the hammer elements.
The hammer elements are fixed and have no horizontal movement, whereas, the print elements are mounted on a horizontally reciprocating shuttle which is driven back and forth by a cam mechanism whereby the print element impact receiving bars move back and forth across the hammer element impactor bars.
The shuttle moves horizontally, in either direction, a distance which is only slightly greater than one dot pitch which is the center-to-center distance between dots.
There are a pair of hammer magnets provided for each hammer element and a dot producing element on each print element.
As the shuttle moves back and forth, the hammer elements may act on the print elements at anytime to produce dots on the print medium at horizontal positions which are predetermined by suitable control logic.
This is accomplished by providing overlapping of the over-under arrangement of the impactor bars on the hammer elements.
The position of the shuttle may be sensed by emitter signals which can be produced by an optical or magnetic emitter means.
An ink ribbon is provided between the dot producing elements and the print medium, such as, paper which is supported and is indexed vertically by an indexing platen or other suitable means