Patents by Inventor Mark Hirst
Mark Hirst 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: 20040103351Abstract: Redundant data storage systems and methods for imaging devices are disclosed. In one embodiment, a control/memory system for an imaging device comprises at least two separate components each including its own processor and memory, and a data recovery module configured to restore data to memory within the control/memory system in the event such data are lost or corrupted. In one embodiment, a data recovery method comprises comparing data stored on various different memories of the imaging device, determining if there is an inconsistency between the data of the various different imaging device memories, determining which data are correct and which data are incorrect if there is an inconsistency, and causing the incorrect data to be replaced with the correct data.Type: ApplicationFiled: November 25, 2002Publication date: May 27, 2004Inventor: B. Mark Hirst
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Patent number: 6721530Abstract: The present disclosure relates to a fusing system for fusing toner to a recording medium. The fusing system includes a fuser roller including a metal layer, a pressure roller in contact with the fuser roller, and an external induction heating element. In addition, the disclosure relates to a method for heating a fuser roller of a fusing system including the steps of positioning an external induction heating element in close proximity to the outer surface of the fuser roller, delivering high frequency current to a coil of the external induction heating element to create a magnetic flux, and directing the magnetic flux toward the fuser roller so as to induce eddy currents within a metal layer of the fuser roller that generate heat within the roller.Type: GrantFiled: March 28, 2001Date of Patent: April 13, 2004Assignee: Hewlett-Packard Development Company, L.P.Inventors: B. Mark Hirst, Mark Wibbels, Kenneth E. Heath
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Patent number: 6710309Abstract: A means for determining the voltage of a power source is disclosed. A portion of the available power from the power source is applied to a heating element. By measuring a rate of change in the temperature of the heating element the input voltage can be determined.Type: GrantFiled: August 23, 1996Date of Patent: March 23, 2004Assignee: Hewlett-Packard Development Company, L.P.Inventor: B. Mark Hirst
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Publication number: 20030222079Abstract: A system for inductively heating a belt employs a magnetic flux intensifier that serves to intensify a magnetic field through which an electrically conductive belt is driven in order to heat said belt. A workpiece such as a sheet of paper having partially dried ink (or electrophotographic toner in need of softening) can be placed in association with the belt and thereby heated in order to dry the ink (or fuse the toner).Type: ApplicationFiled: May 30, 2002Publication date: December 4, 2003Inventors: Robert J. Lawton, Jose Alvaro Barba Villanueva, B. Mark Hirst
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Patent number: 6635864Abstract: A method for determining a scan line error for a scan line, wherein the scan line is produced from one of a plurality of facets of a rotating reflector of a scanning device. The method comprises the steps of (a) determining a difference between a time of an occurrence of a point in a scan line produced from a first facet and a time of an occurrence of a point in a scan line produced from a second facet, and (b) determining from the difference, a scan line error for the scan line produced from the first facet.Type: GrantFiled: July 13, 2001Date of Patent: October 21, 2003Assignee: Hewlett-Packard Development Company, L.P.Inventor: B. Mark Hirst
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Patent number: 6580895Abstract: The present disclosure relates to a fusing system for fusing toner to a recording medium. In one embodiment, the fusing system contains a fuser roller configured as a heat pipe including an inner tube and a coaxial outer tube that is mounted to the inner tube, the inner and outer tubes defining an interior space therebetween that is adapted to contain a liquid and to be evacuated so as be maintained in a vacuum, and a pressure roller in contact with the fuser roller. In another embodiment, the fusing system contains a fuser roller, a pressure roller in contact with the fuser roller, and an external heating roller in contact with the fuser roller, the external heating roller being configured as a heat pipe including an inner tube and a coaxial outer tube that is mounted to the inner tube, the inner and outer tubes defining an interior space therebetween that is adapted to contain a liquid and to be evacuated so as be maintained in a vacuum.Type: GrantFiled: March 28, 2001Date of Patent: June 17, 2003Assignee: Hewlett-Packard Development Company, L.P.Inventors: B. Mark Hirst, Mark Wibbels, Kenneth E. Heath
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Publication number: 20030095423Abstract: The present invention provides a synchronous full-wave AC rectifier connectable to an AC voltage source. In one embodiment, the synchronous rectifier includes a full-wave diode bridge having four bridge diodes. A power switch is coupled in parallel with each bridge diode, and each power switch has a power switch control gate. A power switch control circuit is coupled in parallel with each bridge diode. Each power switch control circuit provides a first control voltage to its associated power switch control gate to cause the power switch to turn on when the parallel-connected bridge diode is forward biased. Each power switch control circuit provides a second control voltage to its associated power switch control gate to cause the power switch to turn off when the parallel-connect bridge diode is reverse biased. The power switch control circuits turn their associated power switches on and off synchronously with the AC voltage source to provide the full-wave rectified AC output.Type: ApplicationFiled: November 21, 2001Publication date: May 22, 2003Inventor: B. Mark Hirst
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Patent number: 6563726Abstract: The present invention provides a synchronous full-wave AC rectifier connectable to an AC voltage source. In one embodiment, the synchronous rectifier includes a full-wave diode bridge having four bridge diodes. A power switch is coupled in parallel with each bridge diode, and each power switch has a power switch control gate. A power switch control circuit is coupled in parallel with each bridge diode. Each power switch control circuit provides a first control voltage to its associated power switch control gate to cause the power switch to turn on when the parallel-connected bridge diode is forward biased. Each power switch control circuit provides a second control voltage to its associated power switch control gate to cause the power switch to turn off when the parallel-connect bridge diode is reverse biased. The power switch control circuits turn their associated power switches on and off synchronously with the AC voltage source to provide the full-wave rectified AC output.Type: GrantFiled: November 21, 2001Date of Patent: May 13, 2003Assignee: Hewlett-Packard CompanyInventor: B. Mark Hirst
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Patent number: 6512913Abstract: The present disclosure relates to a fusing system for fusing toner to a recording medium. The fusing system includes a fuser roller including an elastomeric layer and a heat transport layer disposed around the elastomeric layer, the heat transport layer having high thermal capacity, and a pressure roller in contact with the fuser roller. The present disclosure also relates to a fusing method that helps reduce gloss variation of printed media fused to a recording medium with a fusing system. The method includes the steps of forming a heat transport layer having high thermal capacity at an outer surface of a fuser roller of the fusing system, heating the heat transport layer, and transferring heat from the heat transport layer to the recording medium as it passes through a nip of the fusing system.Type: GrantFiled: March 28, 2001Date of Patent: January 28, 2003Assignee: Hewlett-Packard CompanyInventors: B. Mark Hirst, Mark Wibbels, Kenneth E. Heath
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Publication number: 20030015654Abstract: A method for determining a scan line error for a scan line, wherein the scan line is produced from one of a plurality of facets of a rotating reflector of a scanning device. The method comprises the steps of (a) determining a difference between a time of an occurrence of a point in a scan line produced from a first facet and a time of an occurrence of a point in a scan line produced from a second facet, and (b) determining from the difference, a scan line error for the scan line produced from the first facet.Type: ApplicationFiled: July 13, 2001Publication date: January 23, 2003Inventor: B. Mark Hirst
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Publication number: 20030016403Abstract: A method for refining a length of a scan line, where the scan line is produced from a facet of a scanning device. The method comprises the steps of: (a) acquiring a plurality of scan line lengths produced from the facet, (b) determining from the plurality of scan line lengths, an average scan line length for the facet, and (c) determining from the average scan line length, a scan line length correction for the facet. A method for measuring a length of a scan line comprises the steps of: (a) charging an electrical current integrator to a voltage while a scan line is produced from a facet, (b) measuring the voltage, and (c) determining from the voltage, the length of the scan line produced from the facet.Type: ApplicationFiled: July 13, 2001Publication date: January 23, 2003Inventors: Gerard J. Carlson, B. Mark Hirst, Mark Wibbels
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Publication number: 20020172536Abstract: The present disclosure relates to a fusing system for fusing toner to a recording medium. The system comprises a fuser roller, a pressure roller in contact with the fuser roller, and an external heating roller. In addition, the disclosure relates to a method for heating a fuser roller of a fusing system. The method comprises the steps of providing an external heating roller, contacting an outer surface of the fuser roller with the external heating roller, heating the external heating roller, and rotating the external heating roller and the fuser roller such that heat is transferred from the external heating roller to the fuser roller.Type: ApplicationFiled: March 28, 2001Publication date: November 21, 2002Inventors: B. Mark Hirst, Kenneth E. Heath, Mark Wibbels
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Publication number: 20020141795Abstract: The present disclosure relates to a fusing system for fusing toner to a recording medium. In one embodiment, the fusing system comprises a fuser roller configured as a heat pipe including an inner tube and a coaxial outer tube that is mounted to the inner tube, the inner and outer tubes defining an interior space therebetween that is adapted to contain a liquid and to be evacuated so as be maintained in a vacuum, and a pressure roller in contact with the fuser roller. In another embodiment, the fusing system comprises a fuser roller, a pressure roller in contact with the fuser roller, and an external heating roller in contact with the fuser roller, the external heating roller being configured as a heat pipe including an inner tube and a coaxial outer tube that is mounted to the inner tube, the inner and outer tubes defining an interior space therebetween that is adapted to contain a liquid and to be evacuated so as be maintained in a vacuum.Type: ApplicationFiled: March 28, 2001Publication date: October 3, 2002Inventors: B. Mark Hirst, Mark Wibbels, Kenneth E. Heath
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Publication number: 20020141794Abstract: The present disclosure relates to a fusing system for fusing toner to a recording medium. The fusing system comprises a fuser roller including a metal layer, a pressure roller in contact with the fuser roller, and an external induction heating element. In addition, the disclosure relates to a method for heating a fuser roller of a fusing system comprising the steps of positioning an external induction heating element in close proximity to the outer surface of the fuser roller, delivering high frequency current to a coil of the external induction heating element to create a magnetic flux, and directing the magnetic flux toward the fuser roller so as to induce eddy currents within a metal layer of the fuser roller that generate heat within the roller.Type: ApplicationFiled: March 28, 2001Publication date: October 3, 2002Inventors: B. Mark Hirst, Mark Wibbels, Kenneth E. Heath
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Publication number: 20020141797Abstract: The present disclosure relates to a fusing system for fusing toner to a recording medium. The fusing system comprises a fuser roller including an elastomeric layer and a heat transport layer disposed around the elastomeric layer, the heat transport layer having high thermal capacity, and a pressure roller in contact with the fuser roller. The present disclosure also relates to a fusing method that helps reduce gloss variation of printed media fused to a recording medium with a fusing system. The method comprises the steps of forming a heat transport layer having high thermal capacity at an outer surface of a fuser roller of the fusing system, heating the heat transport layer, and transferring heat from the heat transport layer to the recording medium as it passes through a nip of the fusing system.Type: ApplicationFiled: March 28, 2001Publication date: October 3, 2002Inventors: B. Mark Hirst, Mark Wibbels, Kenneth E. Heath
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Patent number: 6445902Abstract: The present disclosure relates to a fusing system for fusing toner to a recording medium. The fusing system comprises a fuser roller that does not have an internal heat source, a pressure roller that does not have an internal heat source, the pressure roller being in contact with the fuser roller, and an external heat source that heats at least one of the fuser and pressure rollers.Type: GrantFiled: March 28, 2001Date of Patent: September 3, 2002Assignee: Hewlett-Packard CompanyInventors: B. Mark Hirst, Mark Wibbels, Kenneth E. Heath
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Patent number: 6396724Abstract: A DC power supply is disclosed. In one aspect, the DC power supply is a DC bias supply connectable to an AC source. The supply includes a first and second input node connectable to the AC source. A pump capacitor is provided having a first terminal coupled to the first input node and having a second terminal. A pump circuit is coupled between the second terminal of the pump capacitor and the second input node and having first and second output nodes. A storage capacitor is coupled between the output nodes, wherein during a first half-cycle of the AC source the pump circuit causes the pump capacitor accumulate a charge and during a second half-cycle of the AC source the pump circuit causes the pump capacitor to transfer to the storage capacitor the accumulated charge, thereby providing a rectified AC output voltage between the output nodes.Type: GrantFiled: November 21, 2001Date of Patent: May 28, 2002Assignee: Hewlett-Packard CompanyInventor: B. Mark Hirst
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Patent number: 6339211Abstract: A temperature differential over a length of a fuser can result from a thermal load applied to the fuser by media having a dimension, corresponding to a longitudinal axis of the fuser, less then the length of the fuser. The temperature on regions of the surface of the fuser contacting the media is lower than on regions of the surface not contacting the media. With feedback used to control the fuser surface temperature near its center, the fuser surface temperature in regions not contacting the media can become hot enough to damage the fuser. With a heat pipe included in the fuser, heat flows from the higher temperature regions on the surface of the fuser to the lower temperature regions on the surface of the fuser, thereby reducing the peak magnitude of the fuser surface temperature and the magnitude of the temperature differential over the length of the fuser.Type: GrantFiled: July 7, 2000Date of Patent: January 15, 2002Assignee: Hewlett-Packard CompanyInventors: Wayne E Foote, David J Arcaro, Kenneth E Heath, B. Mark Hirst, Mark Wibbels
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Patent number: 6307584Abstract: A color laser printer includes a photoconductor section having photoconductive material configured to be exposed to receive a plurality of color toners in a selective manner representative of a color image to be printed. The printer further includes a scanning section having a plurality of lasers, preferably four lasers, each of the lasers being configured to generate pulsed beams of laser energy to be directed to the photoconductor section to selectively expose the photoconductive material. The scanning section also includes a single, rotating, polygonal-sided mirror having at least four reflective facets corresponding to selected sides of the polygon. The polygonal-sided mirror is positioned relative to the lasers and the photoconductor section such that the pulsed beams of laser energy from each of the lasers are reflected by the reflective facets of the polygonal-sided mirror to a predetermined lineal position on the photoconductive material.Type: GrantFiled: August 19, 1999Date of Patent: October 23, 2001Assignee: Hewlett-Packard CompanyInventors: B. Mark Hirst, K. Trent Christensen
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Patent number: 6294904Abstract: A multiple frequency switching power supply including a pulse width modulation circuit having an output, having an input and having a clock signal input. The power supply also includes a switching transistor having first and second current-carrying electrodes and a control electrode. The first current-carrying electrode is coupled to a voltage source, the control electrode is coupled to the output of the pulse width modulation circuit and the second current-carrying electrode is coupled to a power supply output configured to provide a regulated output voltage. The power supply additionally includes a voltage sensing circuit coupled to the power supply output and having an output coupled to the pulse width modulation circuit input and a switch coupled to the clock input of the pulse width modulation circuit.Type: GrantFiled: September 7, 2000Date of Patent: September 25, 2001Assignee: Hewlett-Packard CompanyInventor: B. Mark Hirst