Abstract: Techniques for controlling moisture content of build material in a three dimensional printer are provided. An example system includes a build material vessel to contain the build material and receive a flow of air, and a humidifier to adjust the humidity of the air flowing into the build material vessel. The system also includes one or more sensors to determine a dew point of the air flowing into the build material vessel. The humidity level of the air flowing into the hopper is controlled by the humidifier to maintain the dew point at a level that will prevent condensation of water inside the build material vessel.

Abstract: In an example, a scanning system includes a scanner device, a first bias member, and a second bias member. The example first bias member is able to apply pressure on a medium towards a scan surface of the scanner device (e.g., apply pressure at a scan zone defined by the boundaries of the scanner device) and the example second bias member is able to orient the medium towards the scan surface before the medium reaches the first bias member.

Abstract: The technology described herein includes a spreader that creates scattered incidental particles in a build chamber when spreading build material is applied in the build platform. One or more vacuum sources create negative pressure zones in one or more receptacles to collect the incidental particles in the build chamber during printing process and thus minimize the scattering of the incidental particles.

Abstract: In one example, a temperature control system for a spreader roller in an additive manufacturing machine includes: a first duct to carry air to an air passage through the roller; a second duct to carry air away from the air passage through the roller; a fan to move air through the ducts; a temperature sensor to sense a temperature of the roller; and a controller to control a flow of air through the ducts based on a temperature sensed by the sensor.

Abstract: In one example, a build material supply system for additive manufacturing includes a mixer to aperiodically rotate a non-circular mixing chamber containing powdered build material to form mixed powdered build material.

Abstract: In one example, a document scanner has a fixed-position scan bar and a built-in translatable calibration target. The scan bar has a linear array of imaging elements aimed in an imaging direction. The calibration target is spaced apart from and parallel to the linear array, and has a planar surface orthogonal to the imaging direction spanning the length of the linear array. The target is translatable during a calibration in a direction in a plane of the surface.

Abstract: In an example implementation, a fluid supply assembly includes a printhead assembly and a carriage comprising a quick-release, hand-operable attachment mechanism to removably attach the printhead assembly to the carriage. A fluid conduit interconnect is rigidly attached to the printhead assembly by a tool-operable fastener. The fluid conduit interconnect is to connect to a fluid conduit to communicate printing fluid from an off-axis printing fluid supply to the printhead assembly.

Abstract: According to an example, an apparatus to prevent media transport jams may include an actuator to load and advance a media within a media path width. The apparatus may also include a first sensor and a second sensor to detect respective edges of the media, in which the first sensor and the second sensor may be positioned outside of a media action area and on opposite sides of the media path width. The apparatus may further include a controller to prevent the actuator from advancing the media along the media path in response to a detection of one or both of the first edge of the media by the first sensor and the second edge of the media by the second sensor.

Abstract: In an example implementation, a fluid supply assembly includes a printhead assembly and a fluid conduit interconnect to connect to a fluid conduit to communicate printing fluid from an off-axis printing fluid supply through the fluid conduit interconnect to the printhead assembly. The fluid supply assembly includes a carriage with a dual attachment mechanism to simultaneously attach the printhead assembly to the fluid conduit interconnect and to the carriage by a single user action.

Abstract: According to an example, an apparatus to prevent media transport jams may include an actuator to load and advance a media within a media path width. The apparatus may also include a first sensor and a second sensor to detect respective edges of the media, in which the first sensor and the second sensor may be positioned outside of a media action area and on opposite sides of the media path width. The apparatus may further include a controller to prevent the actuator from advancing the media along the media path in response to a detection of one or both of the first edge of the media by the first sensor and the second edge of the media by the second sensor.

Abstract: A method of three-dimensional (3D) printing is provided. Print data is received, which defines patterns of at least one agent to be applied to a layer of build material. These patterns are at least partially based on a 3D model of at least one object to be generated. The print data print data is processed to determine regions which are distant from said patterns. The print data is modified to add a further pattern of a detailing agent to be selectively applied to the layer of build material to generate fracture regions in a processed volume of build material.

Abstract: There are disclosed methods and apparatuses for 3D printing post-processing. The methods and apparatuses provide a container for an additive manufacturing system, the container for receiving a build volume of fused and unfused build material. The container comprises a connector for connecting the container to a pressure source, and at least one air hole to allow passage of air into or out of the container. When the connector is connected to the pressure source, there is generated a flow of air through the container between the connector and the at least one air hole so as to remove unfused build material from the container and to help cool the volume of build material.

Abstract: In an example, a scanning system includes a scanner device, a first bias member, and a second bias member. The example first bias member is able to apply pressure on a medium towards a scan surface of the scanner device (e.g., apply pressure at a scan zone defined by the boundaries of the scanner device) and the example second bias member is able to orient the medium towards the scan surface before the medium reaches the first bias member.

Abstract: A build material management apparatus for a three dimensional printing system is provided having a plurality of conduits to connect to a respective plurality of ports of at least one build material container. Processing circuitry is provided to control coupling of a 5 pump interface to the plurality of conduits to independently set, for at least two of the plurality of conduits, a given air flow parameter for cooling build material in the at least one build material container. A build material container and machine executable instructions are also provide.

Abstract: A build material management system for a 3D printing system is described in which one or more input ports of a housing of the build material management system is to connect to one or more respective transportable containers. The transportable containers contain a volume of build material comprising 3D printed parts and a portion of non-fused build material. A pump also comprised within the housing is operable to provide a pressure differential across a conduit network of the build material management system. The pump is connected to the input port(s) by the conduit network. An air-flow caused through at least one of the one or more input ports is controlled by processing circuitry also comprised within the housing. The air-flow causes cooling within the respective transportable container. In one alternative, the housing comprises at least two input ports.

Abstract: In an example implementation, a method of extracting three-dimensional (3D) objects includes forming on a vibratory extraction platform, a build cake comprising a fused 3D object encased within build material and vibrating the extraction platform to break apart the build material and sift it through openings in the extraction platform.

Abstract: An off-axis printhead assembly includes a printhead body that has an engagement element removably attachable to an attachment mechanism of a carriage of a printing system, the attachment mechanism of the carriage removably attachable to an on-axis printhead assembly. A fluid conduit interconnect is removably attached to the printhead body, the fluid conduit interconnect to connect to a fluid conduit to communicate printing fluid from at least one off-axis printing fluid supply through the fluid conduit interconnect to the printhead body.

Abstract: According to an example, an apparatus for controlling a media scan operation may include a first scan module to scan a section of a media, a tracking mechanism to track the media as the media is moved past the first scan module, and a controller. The controller may receive signals corresponding to the media movement from the tracking mechanism, determine, based upon the received signals, a current position of the media, and vary a timing at which the first scan module collects a scan of the section of the media based upon the determined current position of the media.

Abstract: In one example, a temperature control system for a spreader roller in an additive manufacturing machine includes: a first duct to carry air to an air passage through the roller; a second duct to carry air away from the air passage through the roller; a fan to move air through the ducts; a temperature sensor to sense a temperature of the roller; and a controller to control a flow of air through the ducts based on a temperature sensed by the sensor.

Abstract: In one example, a group of interchangeable supply modules to hold powdered build material for additive manufacturing. Each supply module in the group includes an exterior sized and shaped to fit into a mixer; an interior defining a non-circular mixing chamber, and an outlet through which powdered build material may leave the mixing chamber.