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 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: An apparatus and method for compensating for variation of the image placement for each color station in an intermediate transfer drum system. A sensor detects the image placed by the previous station and triggers the imaging on the drum such that it properly registered to the previous image. However, the variation of the drum's radius results in runout which creates an error in the image placement, since the surface drum travel will be larger or smaller than expected. The method to correct for a lead edge offset for radial runout involves dividing the drum into regions and calculating an offset center of each region. As the drum transitions from region to region the offset value is updated to determine when to start imaging for proper placement on the sheet. The offset can be derived from the image runout to find the distance traveled from the transfer point or can be measured directly from color-to-color registration variation.

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 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: 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: An apparatus and method for compensating for variation of the image placement for each color station in an intermediate transfer drum system. A sensor detects the image placed by the previous station and triggers the imaging on the drum such that it properly registered to the previous image. However, the variation of the drum’s radius results in runout which creates an error in the image placement, since the surface drum travel will be larger or smaller than expected. The method to correct for a lead edge offset for radial runout involves dividing the drum into regions and calculating an offset center of each region. As the drum transitions from region to region the offset value is updated to determine when to start imaging for proper placement on the sheet. The offset can be derived from the image runout to find the distance traveled from the transfer point or can be measured directly from color-to-color registration variation.

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 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 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: 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 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 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 an airflow guide structure extending into the opening of the carrier plate, the airflow guide structure configured to flow air at a direction aimed under the printhead and at an oblique angle relative to the movable support surface. 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: An MFD is disclosed. For example, the MFD includes a printhead to dispense print material, an enhancement printhead to dispense an enhancement printing fluid, a processor and a non-transitory computer-readable medium storing a plurality of instructions. The instructions when executed by the processor cause the processor to perform operations that include determining that an automated enhancement feature was selected, analyzing each pixel of an image to be printed to determine one or more pixels that are to receive the enhancement printing fluid, controlling the printhead to print the image, and controlling the enhancement printhead to dispense the enhancement printing fluid on the one or more pixels that are to receive the enhancement printing fluid.

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.

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.