Abstract: In one example, a device for dispensing build material powder in an additive manufacturing machine includes a first dispenser including a first scoop rotatable in a first direction to scoop build material powder into the first dispenser, a second dispenser including a second scoop rotatable in a second direction opposite the first direction to scoop build material powder into the second dispenser, and a leveler between the first dispenser and the second dispenser.

Abstract: According to examples, an apparatus may include a memory on which is stored instructions that when executed by a processor, cause the processor to access a digital file identifying a first plurality of parts to be fabricated in a first level of a build volume in a three-dimensional (3D) fabrication operation and a second plurality of parts to be fabricated in a second level of the build volume. The processor may also determine a first usage of a plurality of nozzles corresponding to fabrication of the first plurality of parts in the first level of the build volume and determine a modification to a property of the second plurality of parts to be fabricated in the second level of the build volume to have a second usage of the plurality of nozzles that differs from the first usage.

Abstract: According to examples, a system may include a recoater and a controller. The controller may identify a structure of a surface of a layer of build material formed on a build platform and may determine whether the identified structure of the surface includes a portion that has a property that is outside of a predefined property level. Based on a determination that the portion has a property that is outside of the predefined property level, an adjustment to be applied to an operation of the recoater to achieve an intended structure of the layer and/or an intended structure of a subsequent layer may be determined and the determined adjustment on the operation of the recoater may be applied.

Abstract: An example system includes an inlet, a guide structure, a heat exchange device and an outlet. In that example the heat exchange device is in thermal contact with the guide structure to change the temperature of print material. The print material may act on the temperature of a print head die while guided through the print head die.

Abstract: According to one example, there is provided a 3D printing build unit comprising a build chamber, a build platform, and a heating element controllable to heat a portion of the contents of the build chamber to a temperature at or above a curing temperature whilst maintaining upper layers of the build chamber at or below a printing temperature.

Abstract: In some examples, a fluid system includes a support structure to attach a fluid dispensing device comprising a fluid chamber to contain a fluid, and an orifice to dispense the fluid from the fluid chamber. The fluid system includes a circulation path comprising a path portion in the fluid dispensing device, the circulation path to circulate a fluid flow through the fluid chamber to remove, from the fluid chamber, a particle ingested through the orifice. A filter in the circulation path is to remove the particle from the circulation path.

Abstract: A method comprises receiving data representing a 3D object model. The 3D object model is for use in generating a 3D object in a build chamber by forming a plurality of successive layers. Each layer is formed by providing a layer of build material and applying a volume of a binder agent to a plurality of voxel locations of the layer of the build material. The volume of the binder agent to be applied to each voxel location is based on the volume of binder agent to be applied to proximate voxel locations of the 3D object.

Abstract: An example service station system may include a guide bar to provide tension on web material. An example print apparatus may include a sensor mounted to a carriage and a controller to use data from the sensor to identify that the web material is incorrectly routed with reference to the guide bar.

Abstract: An example system includes an inlet, a guide structure, a heat exchange device and an outlet. In that example the heat exchange device is in thermal contact with the guide structure to change the temperature of print material. The print material may act on the temperature of a print head die while guided through the print head die.

Abstract: An example service station system may include a guide bar to provide tension on web material. An example print apparatus may include a sensor mounted to a carriage and a controller to use data from the sensor to identify that the web material is incorrectly routed with reference to the guide bar.

Abstract: A fluid ejection device is described. The fluid ejection device has a set of coding elements and a trap element. Each coding element is movable between an initial position and a coded position. The trap element is capable of trapping one or a plurality of the coding elements in the initial position when one or a plurality of other ones of the coding elements is moved from the initial position to the coded position.

Abstract: Example methods for the maintenance of printheads are provided, the printheads comprising a reservoir containing a printing fluid with particles in suspension, and a nozzle plate. Example methods may comprise capping the nozzle plate of the printhead, and rotating the capped printhead. Example maintenance devices for printheads are also provided, comprising a support with a socket to attach a printhead to the support, a drive unit to rotate the support about a rotation axis, and a control unit connected to the drive unit to perform a predetermined rotation cycle.

Abstract: Example methods for the maintenance of printheads are provided, the printheads comprising a reservoir containing a printing fluid with particles in suspension, and a nozzle plate. Example methods may comprise capping the nozzle plate of the printhead, and rotating the capped printhead. Example maintenance devices for printheads are also provided, comprising a support with a socket to attach a printhead to the support, a drive unit to rotate the support about a rotation axis, and a control unit connected to the drive unit to perform a predetermined rotation cycle.

Abstract: Thermal inkjet printing wherein a printhead has ink ejection elements which are energizable by electrical pulses of a given energy with fire pulses of an amplitude (V) and a fire pulse width (fp). A printer controller sends commands to the printhead to spit ink drops, one or more temperature sensors coupled to the printhead measure a temperature of the printhead, and a calibration component coupled to the temperature sensor variably adjusts the fire pulse energy provided to the having ink ejection elements of the printhead.

Abstract: Example methods for the maintenance of printheads are provided, the printheads comprising a reservoir containing a printing fluid with particles in suspension, and a nozzle plate. Example methods may comprise capping the nozzle plate of the printhead, and rotating the capped printhead. Example maintenance devices for printheads are also provided, comprising a support with a socket to attach a printhead to the support, a drive unit to rotate the support about a rotation axis, and a control unit connected to the drive unit to perform a predetermined rotation cycle.

Abstract: A printing method is disclosed, in which a fixing liquid is applied to a print medium both to first regions of the print medium that are to be printed and to second regions of the print medium that are not to be printed. A printing liquid is also applied to the print medium at the first regions of the print medium. The fixing liquid applied to the second regions of the print medium protects the second regions of the print medium from aerosol droplets generated when applying the printing liquid to the first regions of the print medium.

Abstract: A fluid ejection device is described. The fluid ejection device has a set of coding elements and a trap element. Each coding element is movable between an initial position and a coded position. The trap element is capable of trapping one or a plurality of the coding elements in the initial position when one or a plurality of other ones of the coding elements is moved from the initial position to the coded position.

Abstract: An example of a printing fluid supply connector is described that has a first connector and a second connector, where each of the first and second connectors is to fluidly connect to a respective replaceable reservoir of printing fluid. The printing fluid supply connector also has an outlet to fluidly connect to a printer and a selector to selectively fluidly connect one of the first and second connectors to the outlet in response to an electrical control signal or to fluid pressure at the first and second connectors.

Abstract: A printing fluid circulation system is described. The system comprises first and second reservoirs, an outlet to supply printing fluid to a fluid inlet of a printhead, an inlet to receive printing fluid from a fluid outlet of the printhead, and a supply system. The supply system is to operate in a first mode to concurrently supply printing fluid from the first reservoir to the outlet and from the inlet to the second reservoir, and in a second mode to concurrently supply printing fluid from the second reservoir to the outlet and from the inlet to the first reservoir.

Abstract: Thermal inkjet printing wherein a printhead has ink ejection elements which are energizable by electrical pulses of a given energy with fire pulses of an amplitude (V) and a fire pulse width (fp). A printer controller sends commands to the printhead to spit ink drops, one or more temperature sensors coupled to the printhead measure a temperature of the printhead, and a calibration component coupled to the temperature sensor variably adjusts the fire pulse energy provided to the having ink ejection elements of the printhead.