Abstract: A phase-change ink transfer printing process and apparatus (10) applies a thin layer of a liquid forming an intermediate transfer surface (12) to a heated receiving surface, such as a drum (14). Then an ink-jet printhead (11) deposits a molten ink image (26) onto the heated drum where it cools to the drum temperature and solidifies. After the image is deposited, a print medium (21) is heated by a preheater (27) to a predetermined temperature and fed into a nip (22) formed between the heated drum and an elastomeric transfer roller (23) that is biased toward the drum to form a nip pressure that is about twice the yield strength of the ink image. As the drum turns, the heated print medium is pulled through the nip to transfer and fuse the ink image to the print medium. When in the nip, heat from the drum and print medium combine to heat the ink in accordance with a process window (90), making the ink sufficiently soft and tacky to adhere to the print medium but not to the drum.

Abstract: A print drum and associated clamping assembly is provided for use in printing or similar operations. The print drum is characterized by uniform thermal characteristics and is constructed from a material having thermal diffusivity of greater than about 1.3.times.10.sup.-5 m.sup.2 /sec. The print drum may moreover have a highly reflective surface that permits optical sensors to distinguish between the drum and substrate surfaces. Clamping sections of a substrate clamp assembly project through slots provided in the print drum and are raised and lowered to release and clamp a substrate respectively. Other constituents of the clamp assembly are mounted in the hollow interior of the print drum. The print drum and associated clamping mechanism is especially suitable for use in ink jet printing apparatus utilizing thermal phase change inks.