Abstract: A thermal ink jet printhead includes a switched power supply for the intermediate voltage predriver sections. The power supply is switched by a MOSFET connected between an intermediate point of a voltage divider and ground. By switching the power supply, the predriver sections are turned off, unnecessary power consumption and overheating the printhead are avoided.

Abstract: A system controls an ink jet printing apparatus for propelling ink jet droplets on demand from a printhead having a plurality of drop ejectors. In the printhead, each ejector includes a heating element actuable in response to electrical input signals, each input signal having an amplitude and a time duration, selectably applied to the heating element to produce a temporary vapor bubble and cause a quantity of ink to be emitted for the creation of a mark on a copy sheet. The temperature of ink in the printhead is sensed, and a combination of power level and time duration of the electrical input signal for the heating element to result in a desired size of the mark of the copy sheet is selected, by entering the sensed temperature of the ink into a predetermined function relating the energy of the electrical input signal to the corresponding resulting size of the mark on the copy sheet.

Abstract: A thermal ink jet printer is disclosed which has a printhead that is maintained at a substantially constant operating temperature during printing. Printing on demand is accomplished by the ejection of ink droplets from the printhead nozzles in response to energy pulses selectively applied to heating elements located in ink channels upstream from the nozzles which pulses vaporize the ink to form temporary bubbles. To prevent printhead temperature fluctuations during printing, especially in translatable carriage printers, the heating elements not being used to eject droplets are selectively energized with energy pulses having insufficient magnitude to vaporize the ink.

Abstract: An ink jet printhead for printing ink droplets on a recording medium on demand is disclosed, comprising an upper and lower substrate, each having at least one substantially flat surface. The substrate flat surfaces are mated and bonded together with a thick film layer sandwiched therebetween. The flat surface of the upper substrate contains a set of parallel, closed-end grooves for subseqeunt use as ink flow channels and a separate associated recess for subsequent use as an ink manifold for supplying ink to the saet of channels. The flat surace of the lower substrate having an array of heating elements and addressing electrodes formed thereon.

Abstract: The vacuum hold down alignment substrate is formed as an array of precisely aligned alignment substrate subunits. Each subunit is formed with an alignment pattern formed in a photo-patternable or electroformable material. When the plurality of alignment substrate subunits are formed into an array to produce the alignment substrate, the alignment patterns are aligned to receive corresponding patterns in discrete subunit devices which are aligned into an array on the alignment substrate.

Abstract: At least one through opening of predetermined location and dimensions is fabricated in a (100) silicon wafer by orientation dependent etching method after completion of integrated circuits on the wafer, the opening extending through the wafer between a circuit surface of the wafer and an opposite parallel base surface of the wafer and having a predetermined location relative to the integrated circuit on the circuit surface of the wafer.

Abstract: An improved thermal ink jet printhead and method of fabrication thereof is disclosed for the type formed by the mating and bonding of first and second substrates. The first substrate is silicon with {100} crystal plane surfaces and has anisotropically etched in one surface thereof a linear series of through recesses together with opposing outer shallow recesses and a plurality of parallel, elongated grooves. The second substrate has a plurality of heating elements and addressing electrodes patterned on one surface thereof. The through recesses with opposing outer shallow recesses serve as a segmented ink reservoir and the elongated grooves serve as ink channels. Adjacent recesses of the segmented reservoir are separated by the dividing walls. The spacing between vias having a dimension which will permit complete undercutting. The undercutting provides ink flow paths. In one embodiment, the shallow recesses of the segmented reservoir are internally fed through the undercut walls.