Patents by Inventor B. Mark Hirst

B. 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).

  • Publication number: 20030015654
    Abstract: 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: Application
    Filed: July 13, 2001
    Publication date: January 23, 2003
    Inventor: B. Mark Hirst
  • Publication number: 20030016403
    Abstract: 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: Application
    Filed: July 13, 2001
    Publication date: January 23, 2003
    Inventors: Gerard J. Carlson, B. Mark Hirst, Mark Wibbels
  • Publication number: 20020172536
    Abstract: 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: Application
    Filed: March 28, 2001
    Publication date: November 21, 2002
    Inventors: B. Mark Hirst, Kenneth E. Heath, Mark Wibbels
  • Publication number: 20020141795
    Abstract: 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: Application
    Filed: March 28, 2001
    Publication date: October 3, 2002
    Inventors: B. Mark Hirst, Mark Wibbels, Kenneth E. Heath
  • Publication number: 20020141794
    Abstract: 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: Application
    Filed: March 28, 2001
    Publication date: October 3, 2002
    Inventors: B. Mark Hirst, Mark Wibbels, Kenneth E. Heath
  • Publication number: 20020141797
    Abstract: 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: Application
    Filed: March 28, 2001
    Publication date: October 3, 2002
    Inventors: B. Mark Hirst, Mark Wibbels, Kenneth E. Heath
  • Patent number: 6445902
    Abstract: 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: Grant
    Filed: March 28, 2001
    Date of Patent: September 3, 2002
    Assignee: Hewlett-Packard Company
    Inventors: B. Mark Hirst, Mark Wibbels, Kenneth E. Heath
  • Patent number: 6396724
    Abstract: 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: Grant
    Filed: November 21, 2001
    Date of Patent: May 28, 2002
    Assignee: Hewlett-Packard Company
    Inventor: B. Mark Hirst
  • Patent number: 6339211
    Abstract: 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: Grant
    Filed: July 7, 2000
    Date of Patent: January 15, 2002
    Assignee: Hewlett-Packard Company
    Inventors: Wayne E Foote, David J Arcaro, Kenneth E Heath, B. Mark Hirst, Mark Wibbels
  • Patent number: 6307584
    Abstract: 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: Grant
    Filed: August 19, 1999
    Date of Patent: October 23, 2001
    Assignee: Hewlett-Packard Company
    Inventors: B. Mark Hirst, K. Trent Christensen
  • Patent number: 6294904
    Abstract: 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: Grant
    Filed: September 7, 2000
    Date of Patent: September 25, 2001
    Assignee: Hewlett-Packard Company
    Inventor: B. Mark Hirst
  • Patent number: 6181895
    Abstract: The present invention provides image forming devices, image forming methods, and methods of supplying power to an image forming device. According to one aspect of the invention, an image forming device includes an input adapted to couple with an external power source; electrical circuitry configured to provide images; a first power supply coupled with the input and configured to supply electricity from the input to the electrical circuitry; and a second power supply coupled with the input and configured to supply electricity from the input to the electrical circuitry; wherein the electrical circuitry is configured to control the supply of electricity from the first power supply and the second power supply.
    Type: Grant
    Filed: November 5, 1999
    Date of Patent: January 30, 2001
    Assignee: Hewlett-Packard Company
    Inventor: B. Mark Hirst
  • Patent number: 6127816
    Abstract: 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: Grant
    Filed: August 4, 1999
    Date of Patent: October 3, 2000
    Assignee: Hewlett-Packard Company
    Inventor: B. Mark Hirst
  • Patent number: 6122478
    Abstract: A fixing device includes a compliant material positioned between a heating member and a support member. Cyclical heating of the fixing device induces differing amounts of thermal expansion in the support member and the heating member. Deformation of the compliant material reduces the thermally induced mechanical stresses that would have been experienced by the heating member had the heating member been rigidly attached to the support member. Reducing the thermally induced mechanical stresses experienced by the heating member reduces the likelihood of failure of the heating member resulting from fracturing of the heating member.
    Type: Grant
    Filed: August 4, 1999
    Date of Patent: September 19, 2000
    Assignee: Hewlett-Packard Company
    Inventor: B. Mark Hirst
  • Patent number: 6018151
    Abstract: When the media enters the fuser, the added thermal load causes the fuser temperature to dip. Eventually, the control system compensates for the thermal load and stabilizes the fuser temperature at the desired temperature. Depending on several factors, the dip in fusing temperature may cause a degradation in the fusing process. An improved temperature profile can be achieved by increasing the amount of power supplied to the fusing system a predetermined amount of time before the thermal load enters the fusing system. Similarly, the amount of power supplied to the fusing system is decreased a predetermined amount of time before the thermal load exits the fusing system. The Desired Temperature input to the fuser temperature control system is modified to anticipate changes in thermal loads thereby changing the amount of power supplied to the fusing system.
    Type: Grant
    Filed: July 31, 1998
    Date of Patent: January 25, 2000
    Assignee: Hewlett-Packard Co.
    Inventor: B. Mark Hirst
  • Patent number: 6014161
    Abstract: A system and method of calibrating pulsewidth modulation of a laser. The output power of the laser is determined and a signal indicative of the output power is provided to a printer system control computer. The control computer calibrates the pulsewidth modulated signal responsive to the signal indicative of the output power. In a preferred embodiment, the control computer includes a lookup table or a mathematical model. The control computer compensates for timing variations in the pulsewidth modulated signal induced by system components and environmental operating conditions.
    Type: Grant
    Filed: January 31, 1997
    Date of Patent: January 11, 2000
    Assignee: Hewlett-Packard Company
    Inventors: B. Mark Hirst, Mark Wibbels
  • Patent number: 5930553
    Abstract: A consumable having a memory device for storing information such as usage information to be used by a the original manufacturer or re-manufacturer. The memory device can also be used to provided software updates or patches for the microcomputers within an image forming or other office automation device.
    Type: Grant
    Filed: April 25, 1997
    Date of Patent: July 27, 1999
    Assignee: Hewlett-Packard Company
    Inventors: B. Mark Hirst, K. Trent Christensen, Andrew J. Binder
  • Patent number: 5925278
    Abstract: The present invention provides a circuit for heating a heating element to a desired temperature and generating an output from a single common AC power source. First, the AC power is rectified. An inductor and a capacitor form an L section type filter for the DC from the rectifier. The inductor and the capacitor have a resonate frequency that is greater than the AC power frequency. A switch is connected to the heating element. Next, a controller receives a signal that indicates the actual temperature of the heating element along with an indication of the desired temperature. The controller generates an error signal that PWMs the switch thereby controlling the heating element. Another switch is connected to a transformer. A separate controller PWMs the second switch generating the output at the secondary side of the transformer. The two controllers use a pulse width modulating frequency that is greater than the resonate frequency of the inductor and capacitor.
    Type: Grant
    Filed: August 23, 1996
    Date of Patent: July 20, 1999
    Assignee: Hewlett-Packard Company
    Inventor: B. Mark Hirst
  • Patent number: 5835817
    Abstract: A printer/copier apparatus is adapted to receive a replacement ink cartridge that is employed during the printing/copying operation. The apparatus includes a receptacle with a first connector that is coupled to a processor which controls operation of the apparatus. The cartridge includes a second connector which mates with the first connector and a serial access memory that is connected to the second connector. Data transfers are enabled both from and to the memory to enable access and modification of data stored therein that is indicative of cartridge usage, calibration, and to parameters for controlling operation of the apparatus. The invention is applicable to replaceable apparatus used with laser and ink jet printers, copiers, etc.
    Type: Grant
    Filed: July 28, 1997
    Date of Patent: November 10, 1998
    Assignee: Hewlett Packard Company
    Inventors: Michael L. Bullock, Winthrop D. Childers, B. Mark Hirst, Ronald D. Stephens, Jr., Antoni Gil Miquel
  • Patent number: 5811764
    Abstract: The present invention is a control system for controlling the temperature of the fusing system. This control system utilizes the knowledge of the heating characteristics of the fuser filament along with the knowledge that the human eye is most sensitive to temporal changes near the 8 Hz to 10 Hz rate as well as the concept of shape factors to control the rate at which power is applied to the filament to bring the fusing system up to operating temperature. From the study of the electrical characteristics of the heating element it is known that the heating element resistance in the fusing system under study exhibits a thermal time constant of 330 mS while heating. Also, from the summary of flicker regulations it is known that the best reduction in flicker is for the case in which a ramp voltage change is implemented with a ramp time of at least 1 second.
    Type: Grant
    Filed: August 23, 1996
    Date of Patent: September 22, 1998
    Assignee: Hewlett-Packard Company
    Inventor: B. Mark Hirst