Abstract: An n-bit serial shift register in an ink jet print head operates in a print mode or a test mode. When the shift register is operating in the print mode, n bits of print data are serially scanned into n number of bit registers and are then latched out to heater addressing logic circuitry in the print head to control a print operation. When the circuit is operating in the test mode, x bits of test point data from x number of test nodes in the print head are loaded in parallel into x number of the n number of bit registers, and are then serially scanned out to a test data output. In this manner, a single shift register may be used to scan in print data and scan out test data, thereby providing observability and controllability of the internal logic nodes of the print head while minimizing logic size and the number of input/output connections on the print head.

Abstract: The specification discloses an oil combustion system for burning waste oil in which oil is pumped by an oil transfer pump from an oil reservoir through a bouyant swirling filter. The oil is supplied to a high pressure input of a pressure reducing fitting, and is transmitted through the fitting to a low pressure output and a high pressure output. A siphon nozzle head is operable to siphon the oil from the low pressure output of the fitting, to preheat the oil, to atomize the oil and to output the atomized oil. Retention chambers and heat transfer plugs within the nozzle head facilitate preheating of the oil and perform a baffle function.