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).

  • Publication number: 20210221126
    Abstract: 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: Application
    Filed: October 12, 2016
    Publication date: July 22, 2021
    Applicant: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.
    Inventors: Eric Martin, James Michael Gardner, David Maxfield
  • Patent number: 11065867
    Abstract: 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: Grant
    Filed: October 23, 2019
    Date of Patent: July 20, 2021
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Eric T. Martin, Andrew L. Van Brocklin, David Maxfield
  • Patent number: 10725490
    Abstract: 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: Grant
    Filed: October 13, 2016
    Date of Patent: July 28, 2020
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: James Michael Gardner, Eric Martin, David Maxfield
  • Patent number: 10654268
    Abstract: 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: Grant
    Filed: December 5, 2018
    Date of Patent: May 19, 2020
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Gerard Alzona, David Maxfield, Dustin W Blair, Sterling Chaffins, Andrew L Van Brocklin
  • Publication number: 20200055312
    Abstract: 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: Application
    Filed: October 23, 2019
    Publication date: February 20, 2020
    Applicant: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.
    Inventors: Eric T. Martin, Andrew L. Van Brocklin, David Maxfield
  • Patent number: 10493752
    Abstract: 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: Grant
    Filed: February 12, 2018
    Date of Patent: December 3, 2019
    Assignee: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.
    Inventors: Eric T. Martin, Andrew L. Van Brocklin, David Maxfield
  • Patent number: 10369801
    Abstract: 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: Grant
    Filed: November 25, 2014
    Date of Patent: August 6, 2019
    Assignee: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.
    Inventors: Vincent C Korthuis, David Maxfield, Andrew Queisser
  • Publication number: 20190235558
    Abstract: 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: Application
    Filed: October 13, 2016
    Publication date: August 1, 2019
    Applicant: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.
    Inventors: James Michael Gardner, Eric Martin, David Maxfield
  • Patent number: 10336089
    Abstract: 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: Grant
    Filed: March 29, 2018
    Date of Patent: July 2, 2019
    Assignee: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.
    Inventors: Adam L. Ghozeil, Scott A. Linn, David Maxfield, Andrew Van Brocklin
  • Publication number: 20190111676
    Abstract: 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: Application
    Filed: December 5, 2018
    Publication date: April 18, 2019
    Inventors: Gerard Alzona, David Maxfield, Dustin W. Blair, Sterling Chaffins, Andrew L. Van Brocklin
  • Patent number: 10183488
    Abstract: 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: Grant
    Filed: April 30, 2015
    Date of Patent: January 22, 2019
    Assignee: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.
    Inventors: Gerard Alzona, David Maxfield, Dustin W Blair, Sterling Chaffins, Andrew L Van Brocklin
  • Publication number: 20180297370
    Abstract: 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: Application
    Filed: March 29, 2018
    Publication date: October 18, 2018
    Inventors: Adam L. Ghozeil, Scott A. Linn, David Maxfield, Andrew Van Brocklin
  • Patent number: 10082015
    Abstract: 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: Grant
    Filed: September 1, 2016
    Date of Patent: September 25, 2018
    Assignee: ACCU-TALLY, LLC
    Inventors: Charles M. Williams, Lance C. Jordan, Kevin J. Smith, Patrick A. Burns, Jr., David Maxfield, Phillip Phelps, Dale Benditz
  • Patent number: 10029464
    Abstract: 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: Grant
    Filed: September 15, 2017
    Date of Patent: July 24, 2018
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Adam L. Ghozeil, David Maxfield, Peter James Fricke
  • Publication number: 20180162124
    Abstract: 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: Application
    Filed: February 12, 2018
    Publication date: June 14, 2018
    Applicant: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.
    Inventors: Eric T. Martin, Andrew L. Van Brocklin, David Maxfield
  • Patent number: 9987850
    Abstract: 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: Grant
    Filed: February 16, 2017
    Date of Patent: June 5, 2018
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: David Maxfield, Sean P. McClelland
  • Patent number: 9962949
    Abstract: 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: Grant
    Filed: January 30, 2014
    Date of Patent: May 8, 2018
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Adam L. Ghozeil, Scott A. Linn, David Maxfield, Andrew Van Brocklin
  • Patent number: 9956771
    Abstract: 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: Grant
    Filed: September 15, 2017
    Date of Patent: May 1, 2018
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventor: David Maxfield
  • Patent number: 9950517
    Abstract: 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: Grant
    Filed: June 1, 2016
    Date of Patent: April 24, 2018
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Eric T. Martin, Andrew L. Van Brocklin, David Maxfield
  • Publication number: 20180058194
    Abstract: 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: Application
    Filed: September 1, 2016
    Publication date: March 1, 2018
    Inventors: Charles M. Williams, Lance C. Jordan, Kevin J. Smith, Patrick A. Burns, JR., David Maxfield, Phillip Phelps, Dale Benditz