Abstract: There is disclosed additive manufacturing apparatus (10), (22), (34) comprising: a heater (18), (36) to direct radiant heat onto an irradiation region (20) of a build platform (12), at least part of the heater (18), (36) being moveable to cause the irradiation region (20) to traverse over the build platform (12); a coating module (14) moveable relative the heater (18), (36) to traverse the build platform (12) to apply a build material onto the build platform (12); and a print module (16) moveable relative the heater (18), (36) to traverse the build platform (12) to selectively eject a print agent onto the build material.

Abstract: In an example, a method includes acquiring a thermal image of a reflector within an additive manufacturing apparatus through a screen. An energy profile of the thermal image of the reflector may be determined and, based on the energy profile, an operational characteristic of the screen may be determined.

Abstract: A method of forming a three-dimensional object includes detecting, with a thermographic camera, a temperature of a control point within at least one zone of the build material bed, and adjusting a power level supplied to at least one of the lamps of the array of lamps if the detected temperature of the control point of the at least one zone of the build material bed is not equal to a set temperature.

Abstract: A method of forming a three-dimensional object includes detecting, with a thermographic camera, a temperature of a control point within at least one zone of the build material bed, and adjusting a power level supplied to at least one of the lamps of the array of lamps if the detected temperature of the control point of the at least one zone of the build material bed is not equal to a set temperature.

Abstract: There is disclosed additive manufacturing apparatus (10), (22), (34) comprising: a heater (18), (36) to direct radiant heat onto an irradiation region (20) of a build platform (12), at least part of the heater (18), (36) being moveable to cause the irradiation region (20) to traverse over the build platform (12); a coating module (14) moveable relative the heater (18), (36) to traverse the build platform (12) to apply a build material onto the build platform (12); and a print module (16) moveable relative the heater (18), (36) to traverse the build platform (12) to selectively eject a print agent onto the build material.

Abstract: In an example, a method includes acquiring a thermal image of a reflector within an additive manufacturing apparatus through a screen. An energy profile of the thermal image of the reflector may be determined and, based on the energy profile, an operational characteristic of the screen may be determined.

Abstract: In one example, a vapor control heater for a printer includes a housing, a heating element at least partially enclosed by the housing, and a fan to move air over the heating element and into a flow of air from the printer dryer.

Abstract: A three-dimensional (3D) printing device may include a thermal imaging device to record an apparent temperature of the a build platform, and a carriage comprising a diffusely reflective material; wherein the thermal imaging device records an apparent reflected temperature of the diffusely reflective material each time the carriage passes over the build platform and corrects an apparent reflected temperature of a build material on the build platform.

Abstract: Examples of determining the temperature of a print zone in an additive manufacturing system are described. In one case, the additive manufacturing system comprises a print zone, a radiation source, an infra-red sensor and an ambient light sensor. The infra-red sensor is configured to measure the temperature of the print zone, and the ambient light sensor is configured to measure visible electromagnetic radiation. The additive manufacturing system comprises a temperature controller to compensate data from the infra-red sensor for infra-red radiation from the radiation source using data from the ambient light sensor.

Abstract: A drying assembly is disclosed. An example apparatus includes fans; a temperature sensor; a print engine to access instructions to cause a printer to perform a printing operation on media; and a processor responsive to an output of the temperature sensor to control the fans to force air onto the media to cause a substantially uniform temperature to be maintained across a width of the media during the printing operation and to cause a sum of air flow output by the fans to be maintained at a substantially constant value.

Abstract: Apparatus for directing air to media. The apparatus including an impinging plate having an array of orifices. The orifices are arranged in a plurality of rows oblique to the direction of motion of the media, and are also arranged to provide air to the media.

Abstract: In one example, a print zone heater includes a structure defining a plenum, a heating element, a fan to move air over the heating element into the plenum, and a conduit from the plenum to carry heated air into the print zone.

Abstract: In one example, a heating system includes a first heater having a first resistive heating element, a second heater having multiple second resistive heating elements arranged in parallel with a group of the second heating elements having a combined resistance equal to a resistance of the first heating element, and a controller to periodically switch power between the first heating element and the group of second heating elements at a zero crossing of an AC power source.

Abstract: A drying assembly is disclosed. An example apparatus includes fans; a temperature sensor; a print engine to access instructions to cause a printer to perform a printing operation on media; and a processor responsive to an output of the temperature sensor to control the fans to force air onto the media to cause a substantially uniform temperature to be maintained across a width of the media during the printing operation and to cause a sum of air flow output by the fans to be maintained at a substantially constant value.

Abstract: A drying assembly is disclosed. An example apparatus includes fans; a temperature sensor; a print engine to access instructions to cause a printer to perform a printing operation on media; and a processor responsive to an output of the temperature sensor to control the fans to force air onto the media to cause a substantially uniform temperature to be maintained across a width of the media during the printing operation and to cause a sum of air flow output by the fans to be maintained at a substantially constant value.

Abstract: In one example, a heating system includes a first heater having a first resistive heating element, a second heater having multiple second resistive heating elements arranged in parallel with a group of the second heating elements having a combined resistance equal to a resistance of the first heating element, and a controller to periodically switch power between the first heating element and the group of second heating elements at a zero crossing of an AC power source.

Abstract: In one example, a print zone heater includes a structure defining a plenum, a heating element, a fan to move air over the heating element into the plenum, and a conduit from the plenum to carry heated air into the print zone.

Abstract: In one example, a vapor control heater for a printer includes a housing, a heating element at least partially enclosed by the housing, and a fan to move air over the heating element and into a flow of air from the printer dryer.

Abstract: A drying assembly is disclosed. An example apparatus includes fans; a temperature sensor; a print engine to access instructions to cause a printer to perform a printing operation on media; and a processor responsive to an output of the temperature sensor to control the fans to force air onto the media to cause a substantially uniform temperature to be maintained across a width of the media during the printing operation and to cause a sum of air flow output by the fans to be maintained at a substantially constant value.

Abstract: A drying assembly is disclosed. The drying assembly has at least 2 fan units where each fan unit has a fan. The fan speed of each fan is adjusted independently to control the air temperature from the fan. The airflow through all of the fans is maintained at a constant value.