Hewlett-Packard Company

Hewlett-Packard Corporation

Michael B Saunders

James R Hulings

Ross R Allen

Rajeev Badyal

S Dana Seccombe

George Barbehenn

Andre Garcia

Rajeev Babyal

The interconnections for transmitting print commands from a printer to a printhead are reduced by the use of on-printhead circuitry. In a basic embodiment, the printhead driver circuitry includes a matrix of drivers controlled by gates, power and control interconnections. Interconnections are reduced by enabling rows and columns of drivers with the power and control interconnections. A multiplexer may also be added to further reduce control interconnections. In an advanced embodiment, the printhead driver circuitry includes a register for converting a serial stream of print enable signals from the printer into a format for applying such signals concurrently to switching devices for one or more heater resistors. An address generator on the printhead generates address signals in response to an address generating signal from the printer. The printer provides constant power to the printhead so that energizing of the heater resistors is a function of the address and print enable signals and not of the power. Variations on the basic and advanced embodiments are also shown and described.

Printhead with reduced interconnections to a printer

An integrated circuit for use in the printhead of an ink jet printer includes an array circuit for heating an ink reservoir to produce a pattern of ink jets, the array circuit including a plurality of resistor cells arranged into rows and columns. A corresponding number of row and column lines are coupled to the integrated circuit array for selecting and energizing the resistor cells according to the desired printing pattern. An identification circuit integrated into the same substrate as the array circuit includes one or more programmable paths, the programmable paths corresponding and coupled to each row line. The programmable paths each include the serial combination of a programmable fuse and an active device. The opposite end of the programmable paths are coupled together at a common node, which in turn is coupled to an output circuit for providing a single output signal in response to a polling of the row lines. The identification circuit can be programmed and polled without adversely affecting or energizing the array circuit.

Integrated circuit printhead for an ink jet printer including an

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Corvallis, OR, United States of America

Michael B Saunders