Abstract: Examples of the present disclosure relate to a method for providing a status of a radiation emitter of a printing device, the method comprising image sensing at least part of a print agent after deposition onto a print substrate and after heating by the radiation emitter: obtaining, based on the image sensing, an irradiance applied on the heated print agent and providing a status of the radiation emitter in response to determining a deviation of the irradiance with respect to an expected irradiance.

Abstract: A printing unit comprises a movable carriage being movable along a path and having a plurality of energy emitters arranged in an array, a controller to control a supplied energy level of the emitters, and a sensor unit to measure an emitted energy level of each emitter, wherein the controller is to compare the measured energy level with a target energy level associated with the supplied energy level to obtain and to generate a matrix indicating a compensation value for each emitter based on the comparison result so as to calibrate the energy level of comparison result.

Abstract: A build unit for a three-dimensional printer, comprising a housing comprising sidewalls and a build platform movable within the housing. The housing and the build platform form a build chamber. The build unit further comprises a lateral heater mounted on the housing. The lateral heater is operable to apply a uniform housing temperature across all the section of the build unit by delivering variable power density along the housing.

Abstract: An additive manufacturing machine (34) comprising a build material spreading system (2). The spreading system (2) has a moveable spreader (4) with an exterior surface (8) to spread build material. The spreading system (2) also has a heater (10) located separate from the spreader (4). The heater (10) has a heat dissipater (20) extending around the spreader (4) to retain, between the dissipater (20) and the spreader (4), air (36) heated by the dissipater (20).