公开(公告)号：US3987883A

公开(公告)日：1976-10-26

申请号：US568961

申请日：1975-04-17

申请人： Daniel P. Darwin ,  Donald K. Rex

发明人： Daniel P. Darwin ,  Donald K. Rex

IPC分类号： B41J35/04 ,  B41J3/04

CPC分类号： B41J35/04

摘要： An improved mechanism is provided for preventing long-term oil contamination of the print ribbon in a wire matrix printer. In the event that the print ribbon has an excess of oil thereon, it will cause the printed characters to be alternatively too light or too dark thereby reducing the print quality on the document. The print head of the wire matrix printer is operated to an idle or at rest position when printing is not being effected, a camming mechanism retracts the print head away from the platen and document. When this occurs, a stationary member on the printer carriage engages the ribbon and moves it away from contact with the print head in the vicinity of the apertures through which the print wires are guided for printing. With the ribbon moved away from the apertures, the lubricant oils on the print wires do not flow on to the ribbon. The retracting of the print head away from the platen and document by the camming mechanism also permits the easy insertion of new forms into the printer.