The Thermography process from start to finish
A high profile way to deliver your message. Thermographic printing is a practical alternative to engraving (copperplate printing) and is more affordable, but still versatile enough to let you fulfil your most exquisite taste in design. While engraving raises the paper surface, thermographic printing raises the image or type. This is achieved by sprinkling powdered resin onto wet ink, then heat-fusing it onto the sheet. The result is a deliciously textured, high gloss finish. Though a similar look is achieved to die-stamping or engraving, thermographic print will not show the fine details of typography or logotypes.
To achieve an engraved look, a slow-drying litho ink is used and is dusted while wet with a fine powder. When heated, the powder and ink fuse to create a gloss relief "orange peel" effect. A matt laser-proof finish can also be achieved.
Thermography is a post print process combining traditional printing methods coupled with thermography machines.
Thermography machines are constructed with three sections connected by a conveyor belt. The first section applies powdered polymer to the entire sheet followed by a gentle vacuuming to remove the excess powder from the non-imaged and dry ink areas. The areas selected for raised printing are printed with inks that do not contain dryers or hardeners so that they remain wet during the application of powder. This ink will be dried or hardened later during the heating process.
The second section of the process is a vacuum system that removes excess powder from those portions of the paper surface that have not been inked. The sheet is then conveyed through a radiant oven system and exposed to temperatures of 900 to 1300 degrees Fahrenheit. The heating process takes on the order of 2.5 to 3 seconds.
During the heating process, the paper/board has a peak in IR radiant absorption. Through conduction from contact with the paper/board, the powder temperature rapidly increases and starts filming at the edges of the selected raised printing areas. The paper/board then feeds into a convection cooling section where the filming action is effectively 'fixed'.
Thermographic printing lends itself well to the following print and stationery items;