Patents by Inventor Palghat S. Ramesh

Palghat S. Ramesh 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: 11912013
    Abstract: Ink-based digital printing systems useful for ink printing include a rotatable charge-retentive reimageable surface layer configured to receive a layer of fountain solution. The fountain solution is carried to the charge retentive surface by a fog or mist including fountain solution aerosol particles, dispersed gas particles, and charge directors that impart charge to the fountain solution aerosol particles. The charge-retentive reimageable surface may be charged to a uniform potential, and selectively discharged using an ROS according to image data to form an electrostatic latent image. The charged fountain solution adheres to portions of the charge-retentive reimageable surface according to the electrostatic latent image to form a fountain solution image thereon. The fountain solution image can be partially transferred to an imaging blanket, where the fountain solution image is inked. The resulting ink image may be transferred to a print substrate.
    Type: Grant
    Filed: January 19, 2021
    Date of Patent: February 27, 2024
    Assignee: Xerox Corporation
    Inventors: Kathryn F. Murphy, Thomas Wunderer, Anne Plochowietz, David K. Biegelsen, Joerg Martini, David Mathew Johnson, Palghat S. Ramesh
  • Patent number: 11900588
    Abstract: An image based correction system compensates for the image quality artifacts induced by thermal ghosting on evolving imaging member surfaces. With thermal ghosting directly tied to previous image content, a feed forward system determines thermal ghosting artifacts based on images previously rendered and generates an open loop gray-level correction to a current image that mitigates undesirable ghosting. For example, the correction system compensates for the thermal ghosting by making the current image “lighter” in areas that will be imaged onto warmer blanket regions, thereby cancelling out TRC differences between different temperature regions. A temperature sensor is used to measure the temperature of the imaging blanket due to the stresses induced by the image. This data is used to learn the parameters of the temperature model periodically during operation, and used in subsequent corrections to mitigate thermal ghosting in spite of changes in blanket properties over use and time.
    Type: Grant
    Filed: June 2, 2021
    Date of Patent: February 13, 2024
    Assignee: Xerox Corporation
    Inventors: Joseph C. Sheflin, Jack T. Lestrange, Palghat S. Ramesh
  • Patent number: 11890863
    Abstract: A printing system comprises an ink deposition assembly and a media transport device. The ink deposition assembly comprises printheads to deposit a print fluid, such as ink, on print media, such as paper. The media transport device holds the print media against a movable support surface, such as a belt, by vacuum suction platen and transports the print media though a deposition region. The vacuum suction is communicated to the movable through platen holes and platen channels in a vacuum platen. At least some of the platen channels have a high impedance region that has a reduced open cross-sectional area as compared to another region of the platen channel.
    Type: Grant
    Filed: March 31, 2021
    Date of Patent: February 6, 2024
    Assignee: XEROX CORPORATION
    Inventors: Anthony Salvatore Condello, Peter John Knausdorf, Jack T. Lestrange, Palghat S. Ramesh, Joseph C. Sheflin
  • Patent number: 11884086
    Abstract: A color inkjet printer includes an electrode that emits an electric field into a gap between a printhead and a media transport that carries media past the printhead. Image data generated by an optical sensor after an ink image is printed on the media is analyzed to measure at least one image quality metric. When the measured image quality metric is outside of a tolerance range, the voltage of a voltage source electrically connected to the electrode is adjusted to improve the wetting of the media type with the ink ejected by the printhead.
    Type: Grant
    Filed: January 24, 2022
    Date of Patent: January 30, 2024
    Assignee: Xerox Corporation
    Inventors: Palghat S. Ramesh, Jack T. LeStrange, Anthony S. Condello, Joseph C. Sheflin, Peter Knausdorf
  • Publication number: 20240005118
    Abstract: A method of inkjet printer operation identifies a problem with an inkjet printer using a comparison of an index for a printhead map identifying inoperative inkjets in a printhead with indexes for clusters of extracted feature descriptors corresponding to printhead maps for printheads having inoperative inkjets stored in a dictionary in a database operatively connected to a controller in the inkjet printer. The dictionary is developed using unsupervised cluster analysis of datasets comprised of printhead maps identifying inoperative inkjets in a plurality of printheads.
    Type: Application
    Filed: July 1, 2022
    Publication date: January 4, 2024
    Inventors: Palghat S. Ramesh, Qingyu Yang, Christine A. Steurrys
  • Publication number: 20240001669
    Abstract: A method of inkjet printer operation indicates a need for a remedial printhead operation by predicting a number of inoperative inkjets and locations for the inoperative inkjets in at least one printhead in the inkjet printer at a predetermined time. The prediction is made using Markov chain Monte Carlo models that correspond to different ranges of area coverage density for inkjet areas of a printhead.
    Type: Application
    Filed: June 30, 2022
    Publication date: January 4, 2024
    Inventors: Palghat S. Ramesh, Qingyu Yang
  • Patent number: 11850842
    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: Grant
    Filed: March 29, 2021
    Date of Patent: December 26, 2023
    Assignee: 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
  • Patent number: 11827035
    Abstract: A method of operating a printer extends the print zone of the printer by separating at least two printhead modules in the print zone by a distance that is greater than a width of a printhead module. The printhead modules are operated to print multiple color separations of an ink image and operates an optical sensors generates image data of the printed multiple color separations. The image data of the printed color separations are used to adjust distances between printhead modules in the print zone.
    Type: Grant
    Filed: October 1, 2021
    Date of Patent: November 28, 2023
    Assignee: Xerox Corporation
    Inventors: Anthony S. Condello, Jack T. LeStrange, Palghat S Ramesh, Joseph C. Sheflin, Peter Knausdorf
  • Patent number: 11801674
    Abstract: An optical gloss meter above an imaging member surface measures fountain solution surface gloss on the imaging member surface in real-time during a printing operation. The measured gloss corresponds to a thickness of the fountain solution layer and may be used in a feedback loop to actively control 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: Grant
    Filed: January 14, 2021
    Date of Patent: October 31, 2023
    Assignee: Xerox Corporation
    Inventors: Anthony S. Condello, Jack T. Lestrange, Joseph C. Sheflin, Brian M. Balthasar, Palghat S. Ramesh
  • Patent number: 11801693
    Abstract: A printing system comprises an ink deposition assembly, a media transport device, and an airflow control system. The ink deposition assembly comprises a printhead to eject ink through a carrier plate opening in a carrier plate. The media transport device holds a print medium against a movable support surface by vacuum suction and transports the print media through a deposition region. The airflow control system comprises a baffle that is movable between an upstream-blocking configuration and a downstream-blocking configuration, and an actuator configured to move the baffle. In the upstream-blocking configuration the baffle blocks airflow through an upstream side of the printhead opening while allowing airflow through a downstream side of the printhead opening. In the downstream-blocking configuration the baffle blocks airflow through the downstream side of the printhead opening while allowing airflow through the upstream side of the printhead opening.
    Type: Grant
    Filed: March 30, 2021
    Date of Patent: October 31, 2023
    Assignee: XEROX CORPORATION
    Inventors: Peter John Knausdorf, Anthony Salvatore Condello, Jack T. Lestrange, Palghat S. Ramesh, Joseph C. Sheflin
  • Patent number: 11787167
    Abstract: Ink-based digital printing systems useful for ink printing include a secondary roller having a rotatable reimageable surface layer configured to receive fountain solution. The fountain solution layer is patterned on the secondary roller and then partially transferred to an imaging blanket, where the fountain solution image is inked. The resulting ink image may be transferred to a print substrate. To achieve a very high-resolution (e.g., 1200-dpi, over 900-dpi) print with these secondary roller configurations, an equivalent very high-resolution fountain solution image needs to be transferred from the secondary roller onto the imaging blanket. To increase the resolution of the image on the secondary roller, examples include a textured surface layer added to the secondary roller for contact angle pinning the fountain solution on the roll. Approaches to introduce a micro-structure onto the surface layer of the secondary roller, and also superoleophobic surface coatings are described.
    Type: Grant
    Filed: January 19, 2022
    Date of Patent: October 17, 2023
    Assignee: Xerox Corporation
    Inventors: David K. Biegelsen, Joerg Martini, Gregory B. Anderson, Jengping Lu, Palghat S. Ramesh, Anne Plochowietz
  • Patent number: 11766874
    Abstract: Apparatus and method for using a line laser (LL) to quickly mark a substrate or media by utilizing a laser additive on/within the substrate/media, which greatly reduces the power requirement for marking the substrate/media. The combination of the LL wide swath (>305 mm) and the improved media/surface sensitivity to laser wavelength allows the LL marking system to achieve faster marking than other systems. The LL is mounted over a transport which transports the sensitized substrate/media past the LL for marking. The desired image is projected from the LL line by line in synch with the moving media and once the media passes the beam path of the LL, marking is complete. In this case, the media has been physically-altered via the heat generated by the LL interacting with the photosensitized media and is permanent. A second method would use a photosensitizing agent coated on top of the media to be marked.
    Type: Grant
    Filed: November 19, 2021
    Date of Patent: September 26, 2023
    Assignee: Xerox Corporation
    Inventors: Peter J. Knausdorf, Anthony S. Condello, Jack T. Lestrange, Palghat S. Ramesh, Joseph C. Sheflin
  • Patent number: 11760086
    Abstract: A method of operating a printer separates the image content data for a sheet in a print job into multiple color separations and operates a digital air curtain between the printhead modules that print the multiple color separations. Image data of the printed color separations are used to adjust operating parameters for the digital air curtain.
    Type: Grant
    Filed: September 27, 2021
    Date of Patent: September 19, 2023
    Assignee: Xerox Corporation
    Inventors: Joseph C. Sheflin, Palghat S. Ramesh, Anthony S. Condello, Jack T. LeStrange, Peter Knausdorf
  • Publication number: 20230278104
    Abstract: A printer having a pump which includes an inner cavity which retains a liquid metal printing material, and a nozzle, where the nozzle is configured to eject a plurality of liquid metal drops, an actuation coil configured to supply a pulse to the liquid metal to generate an electromagnetic force upon the liquid metal, where the actuation coil supplies a pulse at a first time varying current pulse, where the electromagnetic force causes the nozzle to eject a drop of liquid metal. The actuation coil also supplies a pulse at a second time varying current pulse, where the electromagnetic force is not sufficient to eject a drop of liquid. A method for metal jetting in a printer is also disclosed where differences between the temperature in an upper portion of the pump and the temperature in a lower portion of the pump are minimized.
    Type: Application
    Filed: March 2, 2022
    Publication date: September 7, 2023
    Applicant: XEROX CORPORATION
    Inventors: Palghat S. RAMESH, Viktor SUKHOTSKIY, Christopher T. CHUNGBIN, Paul J. McCONVILLE, Peter M. GULVIN, Gary D. REDDING
  • Publication number: 20230234352
    Abstract: A color inkjet printer includes an electrode that emits an electric field into a gap between a printhead and a media transport that carries media past the printhead. Image data generated by an optical sensor after an ink image is printed on the media is analyzed to measure at least one image quality metric. When the measured image quality metric is outside of a tolerance range, the voltage of a voltage source electrically connected to the electrode is adjusted to improve the wetting of the media type with the ink ejected by the printhead.
    Type: Application
    Filed: January 24, 2022
    Publication date: July 27, 2023
    Inventors: Palghat S. Ramesh, Jack T. LeStrange, Anthony S. Condello, Joseph C. Sheflin, Peter Knausdorf
  • Patent number: 11697296
    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: Grant
    Filed: March 29, 2021
    Date of Patent: July 11, 2023
    Assignee: 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: 20230182201
    Abstract: A method includes ejecting a plurality of drops of a build material from a nozzle of a 3D printer. The build material cools and solidifies after being ejected to form a 3D object. The method also includes controlling an oxidation of the drops, the 3D object or both to create different oxidation levels in first and second portions of the 3D object.
    Type: Application
    Filed: February 8, 2023
    Publication date: June 15, 2023
    Applicant: XEROX CORPORATION
    Inventors: Viktor Sukhotskiy, David A. Mantell, Palghat S. Ramesh, Kareem Tawil, Alexander J. Fioravanti, Dinesh Krishna Kumar Jayabal
  • Publication number: 20230173585
    Abstract: A three-dimensional (3D) metal object manufacturing apparatus is equipped with a magnetic field generator to form a magnetic field selectively about a nozzle from which melted metal drops are ejected. The drops ejected in the presence of the magnetic field have their velocities reduced from the initial velocity at which they are ejected. The reduced velocity increases the time in flight of the drops before they impact their landing areas. The increased travel time enables the melted metal drops to oxidize sufficiently that they bond less tightly than the drops ejected without passing through the magnetic field. Thus, the apparatus can form metal support structures that adhere less tightly to the part portions of the object so they can be more easily removed after printing of the object.
    Type: Application
    Filed: December 7, 2021
    Publication date: June 8, 2023
    Inventors: Douglas K. Herrmann, Chu-Heng Liu, Seemit Praharaj, Jason M. LeFevre, Paul J. McConville, Palghat S. Ramesh
  • Publication number: 20230158811
    Abstract: Apparatus and method for using a line laser (LL) to quickly mark a substrate or media by utilizing a laser additive on/within the substrate/media, which greatly reduces the power requirement for marking the substrate/media. The combination of the LL wide swath (>305 mm) and the improved media/surface sensitivity to laser wavelength allows the LL marking system to achieve faster marking than other systems. The LL is mounted over a transport which transports the sensitized substrate/media past the LL for marking. The desired image is projected from the LL line by line in synch with the moving media and once the media passes the beam path of the LL, marking is complete. In this case, the media has been physically-altered via the heat generated by the LL interacting with the photosensitized media and is permanent. A second method would use a photosensitizing agent coated on top of the media to be marked.
    Type: Application
    Filed: November 19, 2021
    Publication date: May 25, 2023
    Inventors: Peter J. KNAUSDORF, Anthony S. CONDELLO, Jack T. LESTRANGE, Palghat S. RAMESH, Joseph C. SHEFLIN
  • Publication number: 20230150026
    Abstract: A three-dimensional (3D) metal object manufacturing apparatus is configured to eject melted metal drops from an ejector head at different velocities to form different portions of metal object layers with different measurable values of a same physical property. The different velocities are achieved by operating the ejector head with two different electrical voltages. The greater voltage that achieves the higher velocity is about 25% greater than the voltage used to achieve the lesser velocity. By operating the ejector head with the two different voltages different portions of the object can be formed with different physical property characteristics.
    Type: Application
    Filed: November 18, 2021
    Publication date: May 18, 2023
    Inventors: Joseph C. Sheflin, Chu-Heng Liu, Paul J. McConville, Peter Knausdorf, Alexander J. Fioravanti, Palghat S. Ramesh