Abstract: 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.

Abstract: 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. There is also a fluidics system which minimizes accumulation of coagulated ink and includes a double diaphragm having a valving diaphragm which works against the raised lip of a conduit insert and a control diaphragm which works against a valve closing spring.