Heating apparatus, heating method, three-dimensional object forming system, and non-transitory computer-readable storage medium

A heating apparatus comprising:

• an emitter that emits light to a thermal expansion sheet that expands according to a heating amount absorbed, the light being converted into heat by the thermal expansion sheet;
• a relative mover that causes the thermal expansion sheet to move relative to the emitter in a predetermined direction or that causes the emitter to move relative to the thermal expansion sheet in the predetermined direction;
• and
• a controller configured to:
• gradually change an amount of the light emitted by the emitter according to a movement distance from a start position of the relative movement by the relative mover in the predetermined direction, during a period in which the relative mover causes the thermal expansion sheet to move relative to the emitter in the predetermined direction or causes the emitter to move relative to the thermal expansion sheet in the predetermined direction while the light is being emitted by the emitter;
• and
• adjust the amount of the light emitted by the emitter according to a distance between the emitter and the thermal expansion sheet, during the period in which the relative mover causes the thermal expansion sheet to move relative to the emitter in the predetermined direction or causes the emitter to move relative to the thermal expansion sheet in the predetermined direction while the light is being emitted by the emitter,
• wherein the distance between the emitter and the thermal expansion sheet changes during the period in which the relative mover causes the thermal expansion sheet to move relative to the emitter in the predetermined direction or causes the emitter to move relative to the thermal expansion sheet in the predetermined direction while the light is being emitted by the emitter.