Patents by Inventor David Maxfield
David Maxfield has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20210221126Abstract: In some examples, a control apparatus for thermal management of a fluid ejection device includes a thermal controller to detect a number of a plurality of thermal measurements of the fluid ejection device that exceed a thermal threshold, and in response to determining that the number of thermal measurements that exceed the thermal threshold exceeds a count threshold, deactivating a firing controller of the fluid ejection device.Type: ApplicationFiled: October 12, 2016Publication date: July 22, 2021Applicant: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.Inventors: Eric Martin, James Michael Gardner, David Maxfield
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Patent number: 11065867Abstract: Measuring an inkjet nozzle may include taking at least one impedance measurement after the firing command is sent to detect the presence of a drive bubble and taking another impedance measurement to detect a collapse of the drive bubble.Type: GrantFiled: October 23, 2019Date of Patent: July 20, 2021Assignee: Hewlett-Packard Development Company, L.P.Inventors: Eric T. Martin, Andrew L. Van Brocklin, David Maxfield
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Patent number: 10725490Abstract: In some examples, a control circuit for a bypass capacitor includes a switch assembly that is activatable between a first state to connect the bypass capacitor between nodes, and a second state to disconnect the bypass capacitor between the nodes. The switch assembly includes a first switch to activate a first path comprising a first resistance to begin charging the bypass capacitor, and a second switch to, a delayed time after the activating of the first path, activate a second path comprising a second resistance lower than the first resistance, the activated second path connecting the bypass capacitor between the nodes.Type: GrantFiled: October 13, 2016Date of Patent: July 28, 2020Assignee: Hewlett-Packard Development Company, L.P.Inventors: James Michael Gardner, Eric Martin, David Maxfield
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Patent number: 10654268Abstract: In some examples, a controller receives impedance sensor values from an impedance sensor in a printhead, determines whether the impedance sensor values correlate to a production of an effective drive bubble for the printhead, and issues a command to modify a firing parameter for a fluid ejector of the printhead based on the impedance sensor values.Type: GrantFiled: December 5, 2018Date of Patent: May 19, 2020Assignee: Hewlett-Packard Development Company, L.P.Inventors: Gerard Alzona, David Maxfield, Dustin W Blair, Sterling Chaffins, Andrew L Van Brocklin
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Publication number: 20200055312Abstract: Measuring an inkjet nozzle may include taking at least one impedance measurement after the firing command is sent to detect the presence of a drive bubble and taking another impedance measurement to detect a collapse of the drive bubble.Type: ApplicationFiled: October 23, 2019Publication date: February 20, 2020Applicant: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.Inventors: Eric T. Martin, Andrew L. Van Brocklin, David Maxfield
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Patent number: 10493752Abstract: Measuring an inkjet nozzle may include taking at least one impedance measurement after the firing command is sent to detect the presence of a drive bubble and taking another impedance measurement to detect a collapse of the drive bubble.Type: GrantFiled: February 12, 2018Date of Patent: December 3, 2019Assignee: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.Inventors: Eric T. Martin, Andrew L. Van Brocklin, David Maxfield
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Patent number: 10369801Abstract: A liquid propelling component includes a liquid channel, a circuit block. The circuit block includes a first conductor disposed in the liquid channel to be in contact with liquid in the channel and a second conductor insulated from liquid in the channel. The liquid propelling component further includes a memory storing a digital code that corresponds to an analog value of the second conductor under a predefined charge.Type: GrantFiled: November 25, 2014Date of Patent: August 6, 2019Assignee: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.Inventors: Vincent C Korthuis, David Maxfield, Andrew Queisser
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Publication number: 20190235558Abstract: In some examples, a control circuit for a bypass capacitor includes a switch assembly that is activatable between a first state to connect the bypass capacitor between nodes, and a second state to disconnect the bypass capacitor between the nodes. The switch assembly includes a first switch to activate a first path comprising a first resistance to begin charging the bypass capacitor, and a second switch to, a delayed time after the activating of the first path, activate a second path comprising a second resistance lower than the first resistance, the activated second path connecting the bypass capacitor between the nodes.Type: ApplicationFiled: October 13, 2016Publication date: August 1, 2019Applicant: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.Inventors: James Michael Gardner, Eric Martin, David Maxfield
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Patent number: 10336089Abstract: In an implementation, a printhead includes a nozzle and a fluid channel. A sensor plate is located within the fluid channel. An impedance measurement circuit is coupled to the sensor plate to measure impedance of fluid within the channel during a fluid movement event that moves fluid past the sensor plate.Type: GrantFiled: March 29, 2018Date of Patent: July 2, 2019Assignee: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.Inventors: Adam L. Ghozeil, Scott A. Linn, David Maxfield, Andrew Van Brocklin
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Publication number: 20190111676Abstract: In some examples, a controller receives impedance sensor values from an impedance sensor in a printhead, determines whether the impedance sensor values correlate to a production of an effective drive bubble for the printhead, and issues a command to modify a firing parameter for a fluid ejector of the printhead based on the impedance sensor values.Type: ApplicationFiled: December 5, 2018Publication date: April 18, 2019Inventors: Gerard Alzona, David Maxfield, Dustin W. Blair, Sterling Chaffins, Andrew L. Van Brocklin
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Patent number: 10183488Abstract: In some examples, a printhead includes a firing chamber to receive printer fluid, an ejector positioned in the firing chamber to eject printer fluid droplets from the printhead, and a nozzle in fluid communication with the firing chamber. The printhead can further include an impedance sensor positioned in the firing chamber to contact printer fluid to measure impedance values of the printer fluid. The impedance sensor can be connectable to a controller to transmit impedance values of printer fluid to the controller.Type: GrantFiled: April 30, 2015Date of Patent: January 22, 2019Assignee: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.Inventors: Gerard Alzona, David Maxfield, Dustin W Blair, Sterling Chaffins, Andrew L Van Brocklin
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Publication number: 20180297370Abstract: In an implementation, a printhead includes a nozzle and a fluid channel. A sensor plate is located within the fluid channel. An impedance measurement circuit is coupled to the sensor plate to measure impedance of fluid within the channel during a fluid movement event that moves fluid past the sensor plate.Type: ApplicationFiled: March 29, 2018Publication date: October 18, 2018Inventors: Adam L. Ghozeil, Scott A. Linn, David Maxfield, Andrew Van Brocklin
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Patent number: 10082015Abstract: An apparatus for measuring a profile of a tubular string and the components thereof as the tubular string is made up and run into a borehole. The apparatus includes a rotating assembly disposed within a housing, the rotating assembly including a plurality of upper legs, and plurality of lower legs and a plurality of rolling elements, each upper leg having a proximal end and a distal end coupled to an upper ring, each lower leg having a proximal end coupled to a lower ring and a distal end, and each rolling element rotatably coupled to the proximal end of an upper leg and a distal end of a lower leg. The apparatus further includes a sensor for detecting a position of the rolling elements as they engage an exterior surface of a tubular string being made up and run into a borehole from a rig. The apparatus receives the tubular string through aligned central passages in the upper ring, lower ring and the rotating assembly.Type: GrantFiled: September 1, 2016Date of Patent: September 25, 2018Assignee: ACCU-TALLY, LLCInventors: Charles M. Williams, Lance C. Jordan, Kevin J. Smith, Patrick A. Burns, Jr., David Maxfield, Phillip Phelps, Dale Benditz
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Patent number: 10029464Abstract: An example provides a fluid ejection apparatus including a fluid feed slot along a length of a print head die of the fluid ejection apparatus to supply a fluid to a plurality of drop ejectors, control circuitry adjacent to at least one side of the fluid feed slot to control ejection of drops of fluid from the plurality of drop ejectors, and a single power supply connector at an end of the print head die to supply power to the control circuitry.Type: GrantFiled: September 15, 2017Date of Patent: July 24, 2018Assignee: Hewlett-Packard Development Company, L.P.Inventors: Adam L. Ghozeil, David Maxfield, Peter James Fricke
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Publication number: 20180162124Abstract: Measuring an inkjet nozzle may include taking at least one impedance measurement after the firing command is sent to detect the presence of a drive bubble and taking another impedance measurement to detect a collapse of the drive bubble.Type: ApplicationFiled: February 12, 2018Publication date: June 14, 2018Applicant: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.Inventors: Eric T. Martin, Andrew L. Van Brocklin, David Maxfield
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Patent number: 9987850Abstract: A printhead assembly is provided, the printhead assembly including a printhead die, a black fluid slot formed in the printhead die to deliver black printing fluid, and a color fluid slot formed in the printhead die to deliver color printing fluid.Type: GrantFiled: February 16, 2017Date of Patent: June 5, 2018Assignee: Hewlett-Packard Development Company, L.P.Inventors: David Maxfield, Sean P. McClelland
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Patent number: 9962949Abstract: In an implementation, a printhead includes a nozzle and a fluid channel. A sensor plate is located within the fluid channel. An impedance measurement circuit is coupled to the sensor plate to measure impedance of fluid within the channel during a fluid movement event that moves fluid past the sensor plate.Type: GrantFiled: January 30, 2014Date of Patent: May 8, 2018Assignee: Hewlett-Packard Development Company, L.P.Inventors: Adam L. Ghozeil, Scott A. Linn, David Maxfield, Andrew Van Brocklin
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Patent number: 9956771Abstract: An example provides a fluid ejection apparatus including a fluid feed slot to supply a fluid to a plurality of drop ejectors, a first rib at a first side of the fluid feed slot and supporting drop ejection circuitry to control ejection of drops of the fluid from the plurality of drop ejectors, and a second rib at a second side, opposite the first side, of the fluid feed slot supporting a thermal sensor to facilitate determination of a temperature of the first rib and the second rib.Type: GrantFiled: September 15, 2017Date of Patent: May 1, 2018Assignee: Hewlett-Packard Development Company, L.P.Inventor: David Maxfield
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Patent number: 9950517Abstract: Measuring an inkjet nozzle may include taking at least one impedance measurement after the firing command is sent to detect the presence of a drive bubble and taking another impedance measurement to detect a collapse of the drive bubble.Type: GrantFiled: June 1, 2016Date of Patent: April 24, 2018Assignee: Hewlett-Packard Development Company, L.P.Inventors: Eric T. Martin, Andrew L. Van Brocklin, David Maxfield
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Publication number: 20180058194Abstract: An apparatus for measuring a profile of a tubular string and the components thereof as the tubular string is made up and run into a borehole. The apparatus includes a rotating assembly disposed within a housing, the rotating assembly including a plurality of upper legs, and plurality of lower legs and a plurality of rolling elements, each upper leg having a proximal end and a distal end coupled to an upper ring, each lower leg having a proximal end coupled to a lower ring and a distal end, and each rolling element rotatably coupled to the proximal end of an upper leg and a distal end of a lower leg. The apparatus further includes a sensor for detecting a position of the rolling elements as they engage an exterior surface of a tubular string being made up and run into a borehole from a rig. The apparatus receives the tubular string through aligned central passages in the upper ring, lower ring and the rotating assembly.Type: ApplicationFiled: September 1, 2016Publication date: March 1, 2018Inventors: Charles M. Williams, Lance C. Jordan, Kevin J. Smith, Patrick A. Burns, JR., David Maxfield, Phillip Phelps, Dale Benditz