Abstract: The fluid jet applicator orifice plate inspection apparatus provides an optoelectronic inspection system including a laser light source and an optical detector mounted on a carriage for traversing an orifice plate to cause laser light to pass through the orifices one at a time for detection on the other side of the orifice plate by an optical detector. The intensity of the detected light is proportional to the area of an individual orifice through which the laser light has been transmitted. The detector generates light intensity signals which are proportional to the area of the orifices and which signals are processed, digitized, and further processed by a data processor to determine, for example, the relative sizes of the orifices along the plate, the orifice size distribution along the plate and flaws of the individual orifices.

Abstract: A print pulse control and driver circuit for an electrostatic fluid jet applicator is provided which promotes enhanced image quality by adjustably controlling the rising and falling edge duration of print pulses that are applied to the applicator's charge electrode array. The control circuit in pattern printing applications employs a print pulse drive bus which is shared by a large number of high voltage charge electrode drive circuits. Print pulses present on the bus are selectively used to gate high voltage to individual charge electrodes. In addition, the print pulse control circuit includes circuitry for detecting short circuits on an individual electrode basis.

Abstract: A frequency-stabilized oscillator is frequency modulated by band-limited random varying signals used to drive a suitable transducer randomly to and artificially perturb fluid jets in an electrostatic fluid jet applicator. Such random artificial pertubation is desirable (especially with longer cross-machine orifice plates) so as to obscure printing irregularities caused by standing wave or other phenomena. However, such random variations are best made with respect to a highly stabilized center frequency.

Abstract: An auxiliary droplet catcher and a method for its use in an ink jet printing apparatus of the type having charge and deflection electrodes to respectively charge selected droplets and then deflect the selected charge droplets from a normal droplet flight path towards a primary droplet catching structure. The auxiliary droplet catcher is mounted for reciprocal movements between retracted and advanced positions and is moved into the advanced position in response to a control system sensing an inability of the charge and/or deflection electrodes to respectively charge and/or deflect the selected droplets, thereby preventing flooding of a print medium.