| 摘要 |
A jet drop printing head comprises a transportable upper assembly and a lower assembly adapted for receiving the upper assembly in such a manner as to control the alignment between the two assemblies. The upper assembly, which is primarily a fluidics package, carries an orifice plate and fluidic elements for producing a jet-forming flow of printing liquid through a series of orifices in the orifice plate. The upper assembly also carries a set of three rests which have been prealigned for mating engagement with a set of precision machine balls mounted in a charge ring plate carried by the lower assembly. Upon assembly the three rests are readily received by the three balls, and the orifice plate orifices are brought into precise registration with corresponding apertures in the charge ring plate. In this arrangement the charge plate assembly, including the three balls, functions as a reference subassembly, and once an upper assembly has had its three rests adjusted for alignment with any charge plate assembly, then the upper assembly may be mated with any lower assembly carrying a similar charge plate and ball arrangement.
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