PURPOSE: To facilitate the assembly by setting a platen, a paper holding roller and a thermal head support guide on a loading holder/frame block of a trans- thermo material cassette in a trans-thermo type printer.

CONSTITUTION: A platen 4, a paper holding roller 11 pressing a paper on the platen 4 and a guide member 53 for supporting a thermal head 5 provided in such a manner as to be allowed to approach and separated from the platen 4 are set on a frame block 50 concurrently serving as a loading holder 6 for a trans-thermo material cassette. Therefore, to set these components into an equipment case, the frame block 50 is inserted securely between right and left side plates of an image formation unit. This facilitates the assembly of an image formation apparatus.