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.

Abstract: A dross extraction system for a printer is disclosed, which includes an ejector defining an inner cavity associated therewith, the inner cavity retaining a liquid printing material. The dross extraction system also includes a first inlet coupled to the inner cavity of the ejector, a probe external to the ejector, which is selectably positionable to contact the liquid printing material to attract dross thereto, thereby extracting dross from the liquid printing material when the probe is withdrawn from the liquid printing material. A method of extracting dross from a metal jetting printer is also disclosed, which includes pausing an operation of the metal jetting printer, advancing a probe into a melt pool within a nozzle pump reservoir in the metal jetting printer, extracting dross from the metal printing material and onto the probe, retracting the probe from the nozzle pump reservoir, and resuming the operation of the metal jetting printer.

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.

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.

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.

Abstract: A three-dimensional (3D) metal object manufacturing apparatus is equipped with an orifice cleaning system that removes metal drops that have adhered to a plate, an orifice in the plate, and a nozzle ejecting melted metal drops through the orifice during object forming operations. The orifice cleaning system includes an orifice cleaning tool that consists essentially of a soft carbon material, such as graphite. The orifice cleaning tool is configured with a handle that is gripped by an articulated arm to move the orifice cleaning tool against the plate, the orifice, and a portion of the nozzle at the orifice.

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.

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.

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.

Abstract: A three-dimensional (3D) metal object manufacturing apparatus is equipped with a removable vessel to reduce the time required for start-up procedures after the printer is serviced. The removable vessel is filled with solid metal that is heated to its melting temperature before the bulk wire is inserted into the vessel to commence printing operations. The melting of the solid metal in the removable vessel requires less time that the melting of an length of bulk wire adequate to produce a volume of melted metal suitable for printer operation. The solid metal in the removable vessel can be metal pellets, metal powder, or a solid metal insert.

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.

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.

Abstract: A dross extraction implement for a printer is described. The dross extraction implement includes a cylindrical portion having a first section along a length of the cylindrical portion of the extraction implement having a first diameter and a second section along a length of the cylindrical portion of the extraction implement having a second diameter, where the first section is adjacent to the second section. The dross extraction implement is configured to be advanced into and retracted from an inner cavity of an ejector in the printer. A printer using the dross extraction implement and a method of using is also described.

Abstract: A dross extraction system for a printer is disclosed. The dross extraction system includes an ejector defining an inner cavity associated therewith, the inner cavity retaining a liquid printing material. The dross extraction system also includes an inlet coupled to the inner cavity and a conduit external to the ejector having a distal opening, positionable to contact the liquid printing material to attract dross therein, thereby extracting dross from the liquid printing material when a negative pressure is introduced between an internal volume of the conduit and the dross.

Abstract: A method of controlling sensing level in a liquid ejector is disclosed. The method includes filling a reservoir in communication with a liquid ejector with a printing material to a first level set point, receiving a drop out signal from a laser-based level sensor that reads from a surface of a melt pool in the reservoir, pausing an operation of the liquid ejector, adjusting the printing material level set point to a second level set point of printing material in reservoir that is higher than the first level set point, increasing a quantity of printing material in the reservoir to fill the reservoir to the second level set point, and resuming the operation of the liquid ejector.

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.

Abstract: A three-dimensional (3D) metal object manufacturing apparatus is equipped with an orifice cleaning system that removes metal drops that have adhered to a plate, an orifice in the plate, and a nozzle ejecting melted metal drops through the orifice during object forming operations. The orifice cleaning system includes an orifice cleaning tool that consists essentially of a soft carbon material, such as graphite. The orifice cleaning tool is configured with a handle that is gripped by an articulated arm to move the orifice cleaning tool against the plate, the orifice, and a portion of the nozzle at the orifice.

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.

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.

Abstract: A method of controlling sensing level in a liquid ejector is disclosed. The method includes filling a reservoir in communication with a liquid ejector with a printing material to a first level set point, receiving a drop out signal from a laser-based level sensor that reads from a surface of a melt pool in the reservoir, pausing an operation of the liquid ejector, adjusting the printing material level set point to a second level set point of printing material in reservoir that is higher than the first level set point, increasing a quantity of printing material in the reservoir to fill the reservoir to the second level set point, and resuming the operation of the liquid ejector.