An exposure device for a non-impact printing apparatus which includes a plurality of light-emitting elements for forming images, a driver element for individually applying energy output levels to the light-emitting elements, lens for focusing the light emitted by the light-emitting elements, storage ability for storing a list of setting values for setting the energy output levels, wherein the list includes a plurality of series of setting values, each one of the series enabling to attribute at least one setting value to each one of the light-emitting elements, each one of the series being selectable as a function of an exposure device condition. A method is also provided for adjusting a non-impact printing apparatus which includes the step of selecting the most adequate series of setting values on the basis of an analysis of the optical density of printed images on a receiving medium.