Hewlett-packard Company

Grrreen, Inc.

Jaime H Bohorquez

Winthrop D Childers

Clayton L Holstun

Kenneth J Courian

Ulrich E Hess

James W Grace

James R Hulings

Ronald Albert Askeland

David W Swanson

Brian J Keefe

John M Wade

James E Clark

George H Corrigan

James A Feinn

George T Kaplinsky

Charles Edward Schinner

King-Wah W Yeung

John H Dion

Mindy A Hamlin

James G Salter

Tofigh Khodapanah

Niels J Nielsen

Frank Drogo

Scott A Norum

Brian P Canfield

James Robert Schmedake

Arthur R Hart

Susan Tousi

A battery charging system and method, includes a high voltage charger for charging a group or string of series connected battery cells, and a group of individual cell chargers for charging individual ones of the cells. The charging technique includes detecting at least one cell being charged to a predetermined voltage, and then inhibiting the high voltage charger from further charging any of the cells. The individual cell chargers charge individual ones of the cells, except the at least one cell charged to the predetermined voltage.

Battery charging system and method

This present invention is embodied in a printing system for a printhead portion of an inkjet printer. The printing system of the present invention includes a filter, coupled between an ink supply and an inkjet printhead. A filter member having a plurality of holes can be coupled between the ink supply and the microscreen filter. Alternatively, the filter can be a thermally efficient filter comprised of a filter integrated with a heat transfer device and can be coupled to the inkjet printhead.

Filter for an inkjet printhead

An ink-jet swath printer employing a cartridge with a spring bag primary reservoir and an auxiliary ink reservoir interconnected via a tube to form a closed ink replenishment system. The primary reservoir creates a negative pressure which draws ink from the auxiliary reservoir as ink is expelled from the cartridge printhead during printing operations. The auxiliary reservoir can either be mounted on the cartridge carriage or on the printer body. The auxiliary reservoir is a large capacity collapsible bag mounted below the level of the printhead to establish an ink pressure head at the primary reservoir connection which is not so large as to destroy or diminish the negative pressure and allow ink to drool from the printhead, yet is sufficient to permit replenishment of the primary reservoir to avoid printhead ink starvation.

Ink-jet swath printer with auxiliary ink reservoir

Data input received by a printer is printed. Dot data, which indicates location of dots on a print medium, is generated from the data input. Dot shift data is used in order to make sub-pixel shifts in locations of a subset of the dots on the print medium. Pulses are provided to a printhead which result in ink being emitted through nozzles located on the printhead. When placing the dots on the print medium, sub-pixel shifts in locations of the subset of the dots is achieved by time shifting the occurrence of pulses used to generate the dots.

Fractional dot column correction for scan axis alignment during printing

A technique for controlling print quality in an inkjet printer by delivering synchronized heating, non-printing pulses and printing pulses to the ink firing resistors during print firing operations such as during the printing of a swath. A temperature of the printhead substrate is measured and compared against a reference temperature during printing operations. If the measured temperature is below the reference temperature, then the printhead substrate is heated during the printing operations to bring the substrate up to the reference temperature. The heating is done by delivering synchronized heating non-printing pulses and printing pulses to the ink firing resistors during selected print firing periods, wherein either the heating pulses or the printing pulses, but not both, occur during a selected print firing period. The heating pulses are logically OR-ed with the printing pulses to achieve the synchronization.

Temperature control of thermal inkjet printheads by using synchronous

A method of operating a thermal inkjet printer having a thermal inkjet printhead that includes the steps of selecting an ink drop volume, selecting a pulse width that will cause the thermal inkjet printhead to deposit an ink drop having the selected drop volume, and operating the thermal inkjet printhead with the selected pulse width and at an operating energy that is greater than a turn-on energy of the printhead for the selected pulse width.

Control of ink drop volume in thermal inkjet printheads by varying the

A bipolar ink jet driver circuit includes a plurality of individual driver cells having a common collector and a resistive heater element. A common collector obviates the need for any isolation between adjacent driver cells. The driver cells each include two bipolar transistors configured as a Darlington pair, which drive an associated resistive heater element. The cells are grouped together to form individual driver circuits each having a control line for enabling each driver circuit. The cells within each driver circuit are individually addressable via address lines which are coupled to each of the driver elements. The resistive heater elements are actuated by enabling a driver circuit and addressing a driver cell within the enabled driver circuit.

Method for forming a bipolar integrated ink jet printhead driver

An ink pen is provided with a protective capping apparatus to protect against damage caused by the ingress of dirt and debris, the accumulation or solidification of ink, the discharge of static electricity or the like. The protective capping apparatus has a protective cap movable between an open position and a closed position. In the closed position the protective cap shields a portion of an ink pen such as the ink-jets or the electrical contacts.

Protective capping apparatus for an ink-jet pen

A simple and inexpensive method for halftone printing by an inkjet printer is disclosed. Improved halftone printing in an inkjet printer is provided by varying the ink drop volume of an thermal inkjet printhead by controlling the pulse width of the delivered firing pulses.

Variable halftone operation inkjet printheads

Bipolar integrated ink jet printhead driver

A circuit for controlling the power applied to the heater resistor of a thermal inkjet printer printhead wherein the heater resistor is connected to a first source of current. The inventive circuit includes a first transistor having a first terminal connected to the heater resistor, a second terminal connected to a return path for the heater resistor and a simple circuit for maintaining a constant voltage at a third terminal of the transistor. In a particular embodiment, the circuit for maintaining a constant voltage at the third terminal of the transistor includes a diode connected between the second and third terminals and a resistor connected between a second source of current and the third terminal of the transistor. In the illustrative embodiment, the transistor is a bipolar NPN transistor and the anode of the diode is connected to the base terminal thereof. In the best mode, the diode is fabricated by connecting the base and collector terminals of a second transistor fabricated on a substrate with the first transistor. The invention provides a simple, low cost, reliable system for controlling the power applied to the heater resistor of a thermal inkjet printhead which consumes little power.

Power supply for individual control of power delivered to integrated

A thermal ink jet printhead including a substrate, a resistor layer on the substrate having ink drop firing resistors and energy controlling resistors defined therein, a metallization layer adjacent the resistor layer and having metallic interconnections formed therein for providing serial energy controlling connections between predetermined ones of the ink drop firing resistors and predetermined ones of the energy controlling resistors, a plurality of ink containing chambers respectively formed over the metallization layer adjacent respective ones of the ink drop firing resistors, and an orifice plate secured over the chambers and containing a plurality of nozzles respectively associated with the chambers.

Growing community of inventors

Escondido, CA, United States of America

Jaime H Bohorquez