Abstract: A multi-sheet cooling buffer suitable for use in a printing device and a method of sheet processing with the cooling buffer are described. The cooling buffer includes an inlet and an outlet and a sheet cooling mechanism. An array of cooling stations, intermediate the inlet and the outlet, are each configured to receive print media sheets independently from the inlet and direct cooled sheets towards the outlet. In the cooling buffer, multiple print media sheets are able to be cooled contemporaneously in respective ones of the cooling stations.

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.

Abstract: Alignment apparatuses include a frame and contact elements connected to the frame. The contact elements contact items that are to be transported in a processing direction relative to the frame. The contact elements are in permeant fixed positions relative to the frame, and do not move relative to the frame. Adjustable mounts are connected to the frame and move the frame in the processing direction and in a perpendicular cross-processing direction. A controller is electrically connected to the adjustable mounts, and the controller is adapted to control the adjustable mounts to simultaneously move the frame and all the contact elements in the cross-processing direction and the processing direction while rotating the frame. Methods laterally shift imaging on sheets that have had rotational correction performed by such alignment apparatuses.

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.

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: An inkjet printer includes solvent vapor generators that direct two flows of solvent vapor on each side of each printhead in the process direction toward media passing the printheads in the printer. The solvent vapor attenuates the evaporation of ink solvent from ink drops on the nozzle plates or from the ink in the nozzles of the printheads. Thus, the ink on the nozzle plates and in the nozzles does not dry out and the operational status of the inkjets is preserved.

Abstract: An inkjet printer includes solvent vapor generators that direct two flows of solvent vapor on each side of each printhead in the process direction toward media passing the printheads in the printer. The solvent vapor attenuates the evaporation of ink solvent from ink drops on the nozzle plates or from the ink in the nozzles of the printheads. Thus, the ink on the nozzle plates and in the nozzles does not dry out and the operational status of the inkjets is preserved.

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: A coefficient of friction (COF) sensor on a carrier roll surface wetted with fountain solution transferred from an imaging member measures COF of the wetted carrier roll surface in real-time, even between or during printing operations. The transferred fountain solution may be concentrated and/or chilled to solidify before the measurement. The measured COF 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 an imaging or other printing operation to reach a desired uniform thickness for the printing. This fountain solution monitoring system may be fully automated.

Abstract: A method of operating a printer supplies an ink solvent or mixture of ink solvents to porous members positioned adjacent printheads. The ink solvent or solvent mixture evaporates from the porous members to provide a solvent vapor environment in the vicinity of the nozzle plates of the printheads. The solvent vapor environment attenuates the evaporation of ink solvent from ink drops on the nozzle plates or from the ink in the nozzles of the printheads. Thus, the ink on the nozzle plates and in the nozzles does not dry out and the operational status of the inkjets is preserved.

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.

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 holes. 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.

Abstract: A metal ejecting apparatus is disclosed. The metal ejecting apparatus includes a nozzle orifice in connection with the inner cavity and configured to eject one or more droplets of the liquid metal printing material, a float in contact with a surface of the liquid metal printing material, where the float is buoyant within the liquid printing material, and a filament attached to the float on a first end and attached to a level sensing system on a second end. The level sensing system may include an ultrasonic sensor, a visual sensor, a mechanical force sensor, a laser sensor, or a combination thereof. A method of sensing and controlling a level of liquid printing material in a metal jetting apparatus is also disclosed.

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 metal ejecting apparatus is disclosed. The metal ejecting apparatus includes a nozzle orifice in connection with the inner cavity and configured to eject one or more droplets of a liquid metal may include the metal printing material, and a first sensor pair in contact with an internal surface of a lower portion of the inner cavity. Each sensor pair is electrically connected to a printing material feed system where the printing material feed system is configured to receive an electrical signal indicative of an electrical connection from each sensor pair when the metal printing material bridges the electrical connection between each sensor in each sensor pair. A method of controlling level in a metal jetting apparatus is also disclosed.

Abstract: A method of operating a printer supplies an ink solvent or mixture of ink solvents to porous members positioned adjacent printheads. The ink solvent or solvent mixture evaporates from the porous members to provide a solvent vapor environment in the vicinity of the nozzle plates of the printheads. The solvent vapor environment attenuates the evaporation of ink solvent from ink drops on the nozzle plates or from the ink in the nozzles of the printheads. Thus, the ink on the nozzle plates and in the nozzles does not dry out and the operational status of the inkjets is preserved.

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.

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.

Abstract: A marker transport system and a method of operating the marker transport system. A group of print bars is located with respect to a marker transport platen and a marker transport belt. A vacuum source and a pneumatic solenoid block are associated with the marker transport platen. The marker transport platen includes airflow sections divided into process-direction slots and cross-section direction slots. The cross-section direction slots are located beneath the print bars and are connected to the vacuum source via the pneumatic solenoid block, which facilitates an individual control of each of the cross-process direction slots. Pneumatic valves are associated with the pneumatic solenoid block, which supplies a flow of vacuum to the cross-process direction vacuum slots. The pneumatic vales can be timed to allow the vacuum to be present when a sheet is present over a corresponding vacuum slot among the process-direction slots and the cross-section direction slots.

Abstract: A method of operating a printer distributes inkjet operations from frequently used inkjets to lesser used inkjets. The redistribution of the inkjet operations helps reduce the number of inkjets exhibiting cross-process direction error so printhead maintenance operations, such as purging, occur less frequently.