| 摘要 |
An improved fluid jet device and method of keeping a fluid jet head clean a re provided. The face of the fluid jet head includes one or more orifices, through which fluid is jetted. The orifices are formed through convex ridges at the surface of head . In a preferred embodiment of the invention, the slope from the face to the orifice is eithe r generally constant or decreasing, to provide 'the convex shape. In an embodiment of the invention, air is blown over the ridge and over the orifice, to keep dust and debris away from the orific e. The flow of air, the shape of the ridge and the proximity of material on which printing occurs ca n be constructed and arranged to provide laminar flow of air or other gas over the orifice. The downstream side of the ridge from the orifice can have a shallower slope than the upstream side. A vacuum port can be provided on the downstream side.
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