Ink jet print head and cap

摘要

A cap 13, 15, for the print face 9 of a drop-on-demand ink jet printer moves between a closed position, in which it covers the print nozzles on the print face 9, and an open position in which the print nozzles are uncovered, without requiring movement of the print face 9. In the open position, the cap is recessed relative to the front surface 21 of the printhead. For at least part of the movement of the cap, it is further forward than the print face 9, so that it does not slide across and damage the print nozzles. The drop-on-demand ink jet printer may be used to print onto objects 3 conveyed past it, for example on a packing line. The cap 13, 15, does not obstruct the path of the objects 3 even if they pass very close (e.g. 0.5 mm) to the print face 9 because its uncapped position is further back than the front surface 21 of the printhead.

主权项

1. An ink jet printer or a print head for an ink jet printer, the printer or print head having a printing position from which ink can be ejected for printing and the printer or print head being suitable for mounting alongside a conveyor for ejection of ink in a direction sideways across the conveyor so that the conveyor can convey products, to be printed onto, past the printing position of the printer or print head in a conveying direction, the printer or print head comprising:
a ramp portion extending away from the printing position, the ramp portion being suitable to be mounted, when the printer or print head is mounted alongside a conveyor for ejection of ink in the direction sideways across the conveyor, so that it extends upstream, relative to the conveying direction, of the printing position and so that it has a ramp surface facing across the conveyor, the ramp surface being angled relative to the conveying direction with (a) the end of the ramp surface that is furthest from the printing position being further in a direction sideways from the conveyor than the printing position, and (b) a place on the ramp surface spaced from the end being no further in the direction sideways from the conveyor than the printing position, whereby a product conveyed by the conveyor that strikes the ramp surface between its end and the said place will be forced sideways relative to the conveying direction as it is conveyed past the ramp surface so as to be no further in the direction sideways from the conveyor than the printing position before it reaches the printing position; a first sensor, for sensing the presence of a product passing the first sensor, the first sensor being mounted on the said ramp portion; and a second sensor, for sensing the presence of a product passing the second sensor, the second sensor being spaced from the first sensor in the direction from the first sensor towards the printing position.