Pen positioning in page wide array printers

摘要

A method and apparatus for positioning a fluid ejection device such as an inkjet pen, or a plurality of aligned fluid ejection devices, on a supporting frame known as a printbar for page wide array printing involves provision of datum surfaces on each ejection device extending in three orthogonally related planes. The datum surfaces on the fluid ejection devices mate with positioning surfaces on the printbar to hold each fluid ejection device in correct position. A datum surface on a laterally outwardly extending key on each device is engaged by a biasing spring mounted on the printbar to position the device lengthwise of the printbar and also to prevent incorrect installation of the device.