Patents by Inventor Chu-heng Liu

Chu-heng Liu 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).

  • Patent number: 11504766
    Abstract: A method includes moving a first part along a movement path. The method also includes introducing drops of a liquid metal onto the first part using a three-dimensional (3D) printer. The drops of the liquid metal solidify to form a second part that is joined to the first part. The method also includes mechanically joining the second part to a third part.
    Type: Grant
    Filed: October 1, 2020
    Date of Patent: November 22, 2022
    Assignee: XEROX CORPORATION
    Inventors: Jason M. LeFevre, Douglas K. Herrmann, Paul J. McConville, Chu-Heng Liu, Seemit Praharaj
  • Patent number: 11493328
    Abstract: According to aspects of the embodiments, there is provided a method of measuring the amount of fountain solution employed in a digital offset lithography printing system. Fountain solution thickness is measured using a diffractive optical element (DOE) configured with grating surfaces varying in a periodic fashion to hold an amount of fountain solution. When radiated with a light source the combination of the grating surface and the fountain solution therein reduces the scattering of the surface structure (“contrast”) that gives rise to a diffraction pattern. The diffractive optical element can be placed on the printing blanket of the lithography printing system or on a separate substrate.
    Type: Grant
    Filed: December 30, 2020
    Date of Patent: November 8, 2022
    Assignee: Xerox Corporation
    Inventors: Chu-heng Liu, Paul J. McConville, Jason M. Lefevre, Douglas K. Herrmann, Seemit Praharaj
  • Patent number: 11479034
    Abstract: According to aspects of the embodiments, there is provided a method of measuring the amount of fountain solution employed in a digital offset lithography printing system. Fountain solution thickness is measured using a glass roll at a lower temperature than the fountain solution. The lower temperature causes the fountain solution to undergo a change in state and in a solid state the fountain solution crystalizes and changes roll opacity with the thickness of the film. When radiated with a light source the opacity is continuously measured through the surface of the roller. The thickness of the crystallized fountain solution can then be determined via the opacity level increase by the crystallization and the impact to the opacity on the glass roll.
    Type: Grant
    Filed: December 30, 2020
    Date of Patent: October 25, 2022
    Assignee: Xerox Corporation
    Inventors: Douglas K. Herrmann, Chu-heng Liu, Seemit Praharaj, Paul J. McConville, Jason M. LeFevre, Michael J. Levy
  • Publication number: 20220332116
    Abstract: A method for operating a printer can include draining a print material from a printer, placing a sacrificial metal into the printer, ejecting the sacrificial metal from a nozzle of the printer, and cooling to printer to a temperature that is below a melting point of the print material and the sacrificial metal. The print material can be or include aluminum and the sacrificial metal can be or include tin. The print material can be drained from the printer when the print material is in molten form, for example, from about 600° C. to about 2000° C. The sacrificial metal can be ejected from the nozzle at a temperature above the melting point of the sacrificial metal but below the melting point of the print material, for example, below about 300° C. The method can reduce or eliminate cracking of various printer structures such as the nozzle during a shutdown or cooling of the printer.
    Type: Application
    Filed: June 27, 2022
    Publication date: October 20, 2022
    Applicant: XEROX CORPORATION
    Inventor: Chu-heng Liu
  • Patent number: 11475258
    Abstract: A tone reproduction curve for a printing apparatus is periodically generated based on printed items produced by the printing apparatus. The tone reproduction curve is adjusted between periodic print-based generations of the tone reproduction curve by: determining the amount of area coverage of marking material applied by the printing apparatus during printing (in subsequent periods following an initial period in which the tone reproduction curve was generated); weighting the amount of area coverage in each of the subsequent periods differently based on how distant each of the subsequent periods is from the initial period to produce a weighted moving average of the area coverages of the marking material; and adjusting the tone reproduction curve based on the weighted moving average of the area coverages of the marking material.
    Type: Grant
    Filed: August 26, 2021
    Date of Patent: October 18, 2022
    Assignee: Xerox Corporation
    Inventors: Chu-heng Liu, Seemit Praharaj, Jason M. LeFevre, Douglas K. Herrmann
  • Publication number: 20220324031
    Abstract: A method for operating a printer can include placing a first print material into a supply reservoir of the printer. The method also includes placing a second print material into the supply reservoir to combine with the first print material to form a diluted print material. The method also includes causing the diluted print material to exit the supply reservoir. Another method for operating a printer includes adding a first print material having a first melting point to a supply reservoir at a first rate. The method also includes adding a second print material having a second melting point to a supply reservoir at a second rate. The method for operating a printer also includes allowing the first print material and the second print material to combine to form a diluted print material. A printing system is also disclosed.
    Type: Application
    Filed: June 28, 2022
    Publication date: October 13, 2022
    Applicant: XEROX CORPORATION
    Inventor: Chu-heng LIU
  • Patent number: 11467785
    Abstract: A processor maintains image quality degradation for a printing device. A communications device receives a print job that includes instructions to print a plurality of printed sheets in a sheet printing sequence. The processor generates a predicted output image for a mid-job sheet of the printed sheets based on the image quality degradation and the sheet count of the mid-job sheet within the sheet printing sequence. The printing engine alter printing characteristics to print a proof sheet matching an appearance of the predicted output image.
    Type: Grant
    Filed: September 8, 2021
    Date of Patent: October 11, 2022
    Assignee: Xerox Corporation
    Inventors: Seemit Praharaj, Jason M. LeFevre, Chu-heng Liu, Douglas K. Herrmann
  • Publication number: 20220314652
    Abstract: A printing system comprises a printhead to eject a print fluid to a deposition region. Print media are held by vacuum suction against a movable support surface, which moves over a vacuum platen to transport the print media through the deposition region. The vacuum platen has platen holes through which the vacuum suction is communicated. Multiple vacuum plenums are provided to supply the vacuum suction to different groups of the platen hoes. A first vacuum plenum is fluidically coupled to a first group of the platen holes located at least partially in the deposition region, and to a second group of platen holes located upstream of the first group. A second vacuum plenum is fluidically coupled to a third group of the platen holes comprising at least some platen holes located between the first and second groups of platen holes.
    Type: Application
    Filed: March 31, 2021
    Publication date: October 6, 2022
    Applicant: XEROX CORPORATION
    Inventors: Douglas K. HERRMANN, Jason M. LeFEVRE, Chu-Heng LIU, Paul J. McCONVILLE, Seemit PRAHARAJ
  • Publication number: 20220314653
    Abstract: A printing system comprises a printhead to eject a print fluid to a deposition region. Print media are held against a movable support surface via vacuum suction, and the movable support surface transports the print media through the deposition region. A vacuum plenum comprises a vacuum platen over which the movable support surface moves. The vacuum platen has platen holes that communicate the vacuum suction from the vacuum plenum to the movable support surface. An airflow restriction mechanism forms a high impedance zone in the vacuum platen, the high impedance zone comprising a subset of the platen holes. The airflow impedance through the high impedance zone is relatively high compared to the airflow impedance through another subset of the platen holes, which are part of a low impedance zone. The high impedance zone may be located near the printhead to reduce airflow through uncovered platen holes near the printhead.
    Type: Application
    Filed: March 31, 2021
    Publication date: October 6, 2022
    Applicant: XEROX CORPORATION
    Inventors: Chu-Heng LIU, Douglas K. HERRMANN, Jason M. LeFEVRE, Paul J. McCONVILLE, Seemit PRAHARAJ
  • Publication number: 20220314654
    Abstract: A printing system comprises a printhead to eject a print fluid to a deposition region. A movable support surface, such as a belt, is used to transport print media through the deposition region, with the print media being held against the movable support surface by vacuum suction through holes in the movable support surface. A media registration device loads print media onto the movable support surface and registers the print media to a location of the movable support surface. The movable support surface comprises no-suction-regions in which the vacuum suction through the movable support surface is prevented. The no-suction regions extend across the width of the movable support surface in a cross-process direction and are arranged at predetermined intervals along the process direction. The control system causes the media registration device to register each of the print media relative to a respective one of the no-suction-regions.
    Type: Application
    Filed: March 31, 2021
    Publication date: October 6, 2022
    Applicant: XEROX CORPORATION
    Inventors: Chu-Heng LIU, Douglas K. HERRMANN, Jason M. LeFEVRE, Paul J. McCONVILLE, Seemit PRAHARAJ
  • Publication number: 20220314650
    Abstract: A printing system comprises a printhead to eject ink through an opening in a carrier plate to a deposition region. A print medium is held against a movable support surface by vacuum suction communicated through platen holes of a vacuum platen and transported through the deposition region. An airflow control system comprises upstream and downstream valves associated with the printhead, individually addressable channels for the vacuum platen, or both. The upstream and downstream valves are arranged to selectively block and allow airflow through an upstream side or a downstream side, respectively, of the opening in the carrier plate. Actuation of the upstream and downstream valves may be controlled based on a location of the print medium. The channels are arranged to selectively control the supply of vacuum suction to respectively corresponding columns of platen holes. Actuation of the channels may be controlled based on a size of the print medium.
    Type: Application
    Filed: March 30, 2021
    Publication date: October 6, 2022
    Applicant: XEROX CORPORATION
    Inventors: Seemit PRAHARAJ, Douglas K. HERRMANN, Jason M. LeFEVRE, Chu-Heng LIU, Paul J. McCONVILLE
  • Publication number: 20220305819
    Abstract: A printing system comprises a print fluid deposition assembly, a media transport device, and an air flow control system. The print fluid deposition assembly comprises a carrier plate and a printhead arranged to eject a print fluid through an opening of the carrier plate to a deposition region. The media transport device holds a print medium against the movable support surface by vacuum suction and transports the print medium through the deposition region. The air flow control system comprises an air supply unit comprising air flow guide structure extending into the opening of the carrier plate between the carrier plate and the printhead to flow air through the opening. The air flow control system controls the air supply unit to selectively flow the air based on a location of a print medium relative to the printhead.
    Type: Application
    Filed: March 29, 2021
    Publication date: September 29, 2022
    Applicant: XEROX CORPORATION
    Inventors: Patrick Jun HOWE, John Patrick BAKER, Brian M. BALTHASAR, Glenn BATCHELOR, Anthony Salvatore CONDELLO, Ali R. DERGHAM, Timothy P. FOLEY, Douglas K. HERRMANN, Richard A. KALB, Peter John KNAUSDORF, Jason M. LeFEVRE, Jack T. LESTRANGE, Chu-Heng LIU, Paul J. McCONVILLE, Seemit PRAHARAJ, Palghat S. RAMESH, Joseph C. SHEFLIN, Emmett James SPENCE, Robert Jian ZHANG, Megan ZIELENSKI
  • Publication number: 20220305817
    Abstract: A printing system comprises a print fluid deposition assembly, a media transport device, and an air flow control system. The print fluid deposition assembly comprises a printhead to eject a print fluid through an opening of a carrier plate to a deposition region. The media transport device holds a print medium against the movable support surface by vacuum suction and transports the print medium through the deposition region. The air flow control system comprises an air supply unit to selectively flow air through the opening based on a location of a print medium relative to the printhead. The air supply unit comprises an air guide structure comprising an air outlet portion extending into the opening of the carrier plate between the printhead and the carrier plate, the air outlet portion terminating in an end wall that is angled obliquely relative to the movable support surface towards a reverse-process direction.
    Type: Application
    Filed: March 29, 2021
    Publication date: September 29, 2022
    Applicant: XEROX CORPORATION
    Inventors: Douglas K. HERRMANN, Jason M. LeFEVRE, Chu-Heng LIU, Paul J. McCONVILLE, Seemit PRAHARAJ
  • Publication number: 20220305736
    Abstract: An additive manufacturing system has an extruder and a printhead module with a conveyor for moving between the extruder and the printhead module. The extruder is operated to form a support layer having microneedle protrusions. The conveyor moves the support layer having the microneedle protrusions to a position opposite the printhead module for sharpening of the microneedle protrusions and the application of a medicament to the sharpened microneedle protrusions.
    Type: Application
    Filed: March 26, 2021
    Publication date: September 29, 2022
    Inventors: Seemit Praharaj, Chu-Heng Liu, Douglas K. Herrmann, Jason M. LeFevre, Paul J. McConville
  • Publication number: 20220305815
    Abstract: A printing system comprises a print fluid deposition assembly, a media transport device, and an air flow control system. The print fluid deposition assembly comprises a carrier plate and a printhead arranged to eject a print fluid through an opening of the carrier plate to a deposition region. The media transport device comprises a movable support surface to transport a print medium along a process direction through the deposition region, the media transport device holding the print medium against the movable support surface by vacuum suction. The air flow control system is arranged to selectively flow air through the opening of the carrier plate between the carrier plate and the printhead based on a location of a print medium transported by the media transport device relative to the printhead.
    Type: Application
    Filed: March 29, 2021
    Publication date: September 29, 2022
    Applicant: XEROX CORPORATION
    Inventors: Douglas K. HERRMANN, Linn C. HOOVER, Patrick Jun HOWE, Joseph C. SHEFLIN, Robert Jian ZHANG, John Patrick BAKER, Brian M. BALTHASAR, Glenn BATCHELOR, Anthony Salvatore CONDELLO, Ali R. DERGHAM, Timothy P. FOLEY, Richard A. KALB, Peter John KNAUSDORF, Jason M. LeFEVRE, Jack T. LESTRANGE, Chu-Heng LIU, Paul J. McCONVILLE, Seemit PRAHARAJ, Palghat S. RAMESH, Erwin RUIZ, Emmett James SPENCE, Rachel Lynn TANCHAK, Kareem TAWIL, Carlos M. TERRERO, Megan ZIELENSKI
  • Publication number: 20220283683
    Abstract: Devices include first and second frame elements having mounting points connectable to opposite ends (e.g., first end, second end) of the touchscreen. First and second rollers are connected, respectively, to the first and second frame elements. A web of transparent material is supported by and between the first and second rollers. Further, an ultraviolet light device is connected to the second frame element and is positioned to expose the web of transparent material to ultraviolet radiation to disinfect the transparent material between users.
    Type: Application
    Filed: March 3, 2021
    Publication date: September 8, 2022
    Applicant: Xerox Corporation
    Inventors: Douglas K. Herrmann, Seemit Praharaj, Jason M. LeFevre, Paul J. McConville, Chu-heng Liu, Linn C. Hoover, David A. VanKouwenberg
  • Publication number: 20220258464
    Abstract: A drag force sensor on a fountain solution carrier roller surface measures drag force of a fountain solution layer on the fountain solution carrier roller surface in real-time during a printing operation. The measured drag force is used in a feedback loop to actively control the fountain solution layer thickness by adjusting the volumetric feed rate of fountain solution added onto the imaging member surface during a printing operation to reach a desired uniform thickness for the printing. This fountain solution monitoring system may be fully automated.
    Type: Application
    Filed: February 17, 2021
    Publication date: August 18, 2022
    Inventors: Jack T. LESTRANGE, Joseph C. SHEFLIN, Palghat S. RAMESH, Anthony S. CONDELLO, Brian M. BALTHASAR, Seemit PRAHARAJ, Chu-heng LIU, Paul J. MCCONVILLE, Douglas K. HERRMANN, Jason M. LEFEVRE
  • Publication number: 20220257810
    Abstract: An apparatus includes, among other components, a frame adapted to be connected to the exterior surface of a device that has a touchscreen. A retractable cover is operatively connected to the frame. The size of the retractable cover is equal to at least the size of the touchscreen, and the retractable cover is positioned to extend so as to cover the touchscreen. At least one ultraviolet light is also operatively connected to the frame. The ultraviolet light is positioned to direct ultraviolet lighting toward the touchscreen when the retractable cover extends to cover the touchscreen.
    Type: Application
    Filed: February 17, 2021
    Publication date: August 18, 2022
    Applicant: Xerox Corporation
    Inventors: Seemit Praharaj, Douglas K. Herrmann, Chu-heng Liu, Paul J. McConville, Jason M. LeFevre, Linn C. Hoover, David A. VanKouwenberg
  • Publication number: 20220247888
    Abstract: A system and method enable determining a total colorant limit for printing images. The system includes memory which stores instructions for: determining a grain value for each of a set of printed patches printed on a first print media, the grain value being based upon a visual contrast sensitivity function computed for the respective patch, the set of printed patches including patches printed on the print media at different total colorant values; determining a total colorant limit for the first print media, as a function of the total colorant values and corresponding grain values for the printed patches in the set, wherein the total colorant limit is a total colorant value which corresponds to a grain value which does not exceed a threshold grain value for the first print media. A processor executes the instructions.
    Type: Application
    Filed: February 3, 2021
    Publication date: August 4, 2022
    Applicant: Xerox Corporation
    Inventors: Stuart A. Schweid, John T. Newell, Chu-Heng Liu, Roger L. Triplett, Mojgan Rabbani, Martin S. Maltz, David A. VanKouwenberg, Seemit Praharaj, Douglas R. Taylor, Martin L. Frachioni, Paul J. McConville
  • Patent number: 11400714
    Abstract: A method for operating a printer can include draining a print material from a printer, placing a sacrificial metal into the printer, ejecting the sacrificial metal from a nozzle of the printer, and cooling to printer to a temperature that is below a melting point of the print material and the sacrificial metal. The print material can be or include aluminum and the sacrificial metal can be or include tin. The print material can be drained from the printer when the print material is in molten form, for example, from about 600° C. to about 2000° C. The sacrificial metal can be ejected from the nozzle at a temperature above the melting point of the sacrificial metal but below the melting point of the print material, for example, below about 300° C. The method can reduce or eliminate cracking of various printer structures such as the nozzle during a shutdown or cooling of the printer.
    Type: Grant
    Filed: December 22, 2020
    Date of Patent: August 2, 2022
    Assignee: XEROX CORPORATION
    Inventor: Chu-Heng Liu