Phase Change Ink Jet

In contrast to continuous ink jet printers, this ink jet printing technology only generates an ink droplet if it is to be ejected onto the substrate to form a dot, thus the terminology: drop-on-demand (DOD), or impulse jet print. Solid ink, consisting mainly of a transparent mixture of synthetic waxes, is used in phase change printers. It is purchased in the form of a pellet or stick, which is inserted into the printhead, where it is partly heated so as to form a liquid. This hot wax is then ejected by a piezoelectric printhead onto the medium. As the droplet hits the substrate, it freezes immediately, without allowing much of its substance to penetrate the surface of the paper. One of the problems associated with phase change prints is that the image might be more susceptible to abrasion than a liquid ink print, but with a final step of cold pressure fusing the bond between the ink and the medium is greatly improved and the spherical droplet form is flattened out.

Other Given Names: solid ink jet, heat-melt ink jet Dates: since 1991 (Tektronix Phaser III printer) Colorant: synthetic waxes with dyes Medium: no restrictions in material, but usually uncoated media Inscriptions: Contribute to this category! Formats: Contribute to this category! Surface: Printed areas, especially those with a heavy coating of ink, have a distinctly glossy surface that differs from that of the substrate. A distinct relief that is especially visible at borders between light and dark areas when viewed with raking light at an extremely small angle is an indicator for ink on the surface of the print (Figure II). Although it might be damaging to the object, a finger can also be run over a printed and adjacent non-printed area. A slight relief might be discernible to the touch, which would indicate that the ink dots are hard spheres resting on the surface of the print. Although an electrophotographic print will also have a relief effect, it is not quite as prominent as that apparent on a phase change ink jet print. The surface is easily scratched or abraded. Image Quality: brilliant, saturated colors, dots have sharp edges that do not bleed or feather. The image consists of round shiny dots that form a separate layer on top of the substrate. In general, a continuous tone effect is not achieved with phase change printing. Applications: Contribute to this category!

Figure I. Tektronix 350 (uncoated bond paper, phase change), 30 x magn.   Figure II. Apparent relief on Tektronix 350 (phase change) in raking light, 30 x magn.