Satya G Prakash

US Patent:

6367147, Apr 9, 2002

Filed:

Mar 5, 2001

Appl. No.:

09/802534

Inventors:

Matthew Giere - San Diego CA
Noah C. Lassar - San Diego CA
Satya Prakash - Poway CA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

H05K 320

US Classification:

29611, 29831

Abstract:

In order to overcome inefficient power dissipation in parasitic resistances and to provide economies in the power supply, a higher resistance value heater resistor is employed in a thermal inkjet printhead. Higher current densities in a high resistance segmented heater resistor are reduced by employing a shorting bar divided by a current balancing resistor.

US Patent:

6422688, Jul 23, 2002

Filed:

Mar 6, 2001

Appl. No.:

09/801135

Inventors:

Matthew Giere - San Diego CA
Noah C. Lassar - San Diego CA
Satya Prakash - Poway CA

Assignee:

Hewlett-Packard Company - Palo-Alto CA

International Classification:

B41J 205

US Classification:

347 62

Abstract:

In order to overcome inefficient power dissipation in parasitic resistances and to provide economies in the power supply, a higher resistance value heater resistor is employed in a thermal inkjet printhead. Higher current densities in a high resistance segmented heater resistor are reduced by employing a shorting bar divided by a current balancing resistor.

US Patent:

6565178, May 20, 2003

Filed:

Oct 29, 2001

Appl. No.:

10/002751

Inventors:

Matthew D Giere - San Diego CA
Satya Prakash - Poway CA
Michael J. Barbour - Corvallis OR

Assignee:

Hewlett-Packard Development Company, L.P. - Houston TX

International Classification:

B41J 2938

US Classification:

347 17

Abstract:

An apparatus includes a substrate and a resistive element attached to a region of the substrate and formed of a first material having a first temperature coefficient of resistivity. In addition, the apparatus includes a pair of traces coupled to the resistive element, attached to the substrate, and formed of a second material having a second temperature coefficient of resistivity with the first material selected so that the first temperature coefficient of resistivity exceeds the second temperature coefficient of resistivity. An apparatus includes a substrate and a resistive element disposed onto a first region of the substrate and formed of a first material having a first temperature coefficient of resistivity. In addition, the apparatus includes a pair of traces coupled to the resistive element and each formed of a first plurality of sections of a second material having a second temperature coefficient of resistivity and a second plurality of sections of a third material having a third temperature coefficient of resistivity.

US Patent:

6582040, Jun 24, 2003

Filed:

Sep 28, 2001

Appl. No.:

09/967079

Inventors:

Patrick J Coven - Albany OR
Satya Prakash - Poway CA
Mark S Barbour - Corvallis OR

Assignee:

Hewlett-Packard Company - Fort Collins CO

International Classification:

B41J 2938

US Classification:

347 11, 347 10

Abstract:

A method of ejecting fluid from an ejection device is described. This method includes adding fluid to a firing chamber, and passing a first amount of charge through a heating element of the firing chamber. The first amount of charge causes the heating element to emit a first quantity of thermal energy, thereby forming a vapor bubble in fluid adjacent the heating element to eject fluid from the firing chamber. A second amount of charge is passed through the heating element to cause the heating element to emit a second amount of thermal energy that is insufficient to eject fluid from the firing chamber.

US Patent:

6612673, Sep 2, 2003

Filed:

Apr 29, 2002

Appl. No.:

10/134813

Inventors:

Matthew Giere - San Diego CA
Satya Prakash - Poway CA
Ronald A. Askeland - San Diego CA

Assignee:

Hewlett-Packard Development Company, L.P. - Houston TX

International Classification:

B41J 2938

US Classification:

347 14, 347 17

Abstract:

The present invention includes as one embodiment an inkjet printing system, having a substrate, a plurality of heating elements disposed on the substrate, an ink ejection assembly adjacent the substrate forming a plurality of ink ejection chambers, each chamber associated with a different one of the heating elements and a controller operatively connected to the heating elements, the controller receiving print data and processing the print data to predict thermal conditions of a subset of the ink ejection chambers for selectively operating the corresponding heating elements of the subset.

US Patent:

6719398, Apr 13, 2004

Filed:

Oct 2, 2000

Appl. No.:

09/677837

Inventors:

David McElfresh - San Diego CA
Satya Prakash - Poway CA
Naoto Kawamura - Corvallis OR

Assignee:

Hewlett-Packard Development Company, L.P. - Houston TX

International Classification:

B41J 2015

US Classification:

347 21, 347 34, 347 28

Abstract:

An inkjet printer includes a printhead having a plurality of ink orifices formed therein. During printing, ink drops are ejected through the ink orifices into a print zone between the printhead and a print medium with an intended ink drop trajectory toward the print medium. An air movement system directs an air stream to the print zone substantially parallel to the intended ink drop trajectory as the ink drops are ejected during printing so as to affect air currents acting on the ink drops during printing and prevent print defects caused by the air currents. The air stream, however, does not disrupt the intended trajectory of the ink drops during printing.

US Patent:

6886905, May 3, 2005

Filed:

May 16, 2003

Appl. No.:

10/439700

Inventors:

David McElfresh - San Diego CA, US
Satya Prakash - Poway CA, US
Naoto Kawamura - Corvallis OR, US

Assignee:

Hewlett-Packard Development Company, L.P. - Houston TX

International Classification:

B41J002/165
B41J002/015

US Classification:

347 21, 347 34

Abstract:

A printer for printing on a print medium includes a printhead having ink orifices formed therein through which ink drops are ejected into a print zone between the printhead and the print medium during printing, wherein the printhead has a scan axis oriented substantially perpendicular to a first column and a second column of the ink orifices and along which the printhead traverses during printing, and an air movement system directing a stream of gas to the print zone substantially parallel to the first column and the second column of the ink orifices and offset from and between the first column and the second column of the ink orifices as the ink drops are ejected during printing.

US Patent:

6966693, Nov 22, 2005

Filed:

Jan 14, 2003

Appl. No.:

10/345637

Inventors:

Satya Prakash - Poway CA, US
Winthrop D. Childers - San Diego CA, US

Assignee:

Hewlett-Packard Development Company, L.P. - Houston TX

International Classification:

G01K007/42
G01K017/06

US Classification:

374163, 374 29, 374110, 702136

Abstract:

A thermal characterization chip comprising a substrate having overlying electronics, the electronics including semiconductor circuitry and thin film circuitry overlying the semiconductor circuitry; wherein the electronics define a plurality of thermal domains, each of the domains defining a portion of a receiving surface for receiving an external influence that alters a thermal parameter within the thermal domains; and wherein the electronics further comprises monitoring circuitry for monitoring the thermal parameter in each of the thermal domains over a test time period.