Abstract: A print head for impact printers of the dot matrix type comprising a hollow die cast housing having solenoids mounted upon a rear wall thereof and having print wires driven thereby and extending through the rear wall and hollow housing toward the forward end. A plastic bearing is releasably mounted in the forward wall and serves as a low friction bearing for the reciprocating print wires and to prevent abrasive wear of the print wires when in the retracted position. The guide means mounted within the housing and intermediate the forward and rearward ends thereof support guide tubes for maintaining relative positioning of the print wires as well as maintaining their desired natural curvature.The plastic bearing is formed of a plastic material for significantly increasing operating life and which is compliant to attenuate a significant amount of side loading due to impact. The plastic bearings are admixed with additives to make the bearings self lubricating.

Abstract: The print head in a high-speed printer of the dot matrix type is provided with a bearing comprising an element fixedly attached to the front wall of a plastic block. The element is made of a material substantially harder than plastic, such as metal or a jewel. Guide passages extending through the element are aligned with similar guide passages in the plastic block and are axially directed towards a paper document. The forward end of the print head is provided with slots for receiving the plastic block which may be releaseably secured into position by means of a substantially U-shaped compliant brad, greatly simplifying both assembly and disassembly thereof.

Abstract: A thermal print head assembly preferably for use with temperature sensitive impression material in a dot-matrix line printer includes a housing having a plurality of electrically actuatable means for impinging upon the impression material; means for guiding each of the plurality of impinging means to form a straight line at the housing front end and adjacent the impression material; and electrical means positioned within the housing for heating the impinging means without interfering with their movement through the frong housing end and being insulated from the housing to prevent excessive heating thereof. In a preferred embodiment, the electrical heating means is energized simultaneously with the motor of the line printer to maintain the forward ends of the impinging means at a temperature of the order of 300.degree.F. to allow printing on thermally activated paper.