The layup was held in position by a lid with an inflatable rubber bladder that was latched down by the user.
In subsequent versions, beginning with the Model 17, the layup was fed into a slot, and continuously exposed as it passed the lamp and reflector.
As copying technology advanced, Thermofax machines were subsequently marketed as a method of producing transparencies (viewgraphs) for overhead projector presentations.
Textile and Printmaking artists use these machines for creating silk screens in several seconds by running a piece of Riso film through with a photocopied image.
When the Riso film is exposed to the infrared bulb inside the machine, the saran plastic emulsion side opens up wherever there is an ink toner on the photocopy.
Model 45EGA was manufactured with an electrical defect that requires a conversion kit to be installed for safe use of the machine.
Since the heat absorption of the ink does not necessarily correlate with its visible appearance, there were occasional idiosyncrasies; some inks that looked nearly black to the eye might not copy at all, and an exposure setting that worked well for some originals might require a change to make usable copies with another.