Disc Print Methods Explained
Offset Lithographic Print (for CMYK images)Disc label artwork is directly printed onto the disc surface using high-quality waterless offset printing. Offset printing quality is often superior to that of screen printing due to higher line count and thinner ink film layers. The offset printing process begins with a digital file, which are output directly to the offset plate in 4 separated colors; Cyan, Magenta, Yellow and Black. The screen printing process is then used to print a white primer layer, providing the artwork with a bright, smooth surface that more closely resembles coated paper stock. After the primer print, the disc is cured using UV light and passed through the four offset print heads, curing after each station. In some cases, a sixth color is applied using the screen printing process and the disc is cured again.After printing, the disc label is inspected using a high-speed digital vision system. In some cases, the read-side of the disc is inspected using a similar method. Screen Print (for Special Pantone colours) The screen printing process begins with color separated, positive, emulsion-up film. The film is output from customer supplied electronic files. If all inspection criteria are met, the film is sent into production. Screens are made of a fine mesh cloth which is stretched tightly over a metal frame and glued into place. A thin layer of light-sensitive emulsion is applied to each screen. The film is placed on top of an emulsion-coated screen and exposed to a bright light. The light reacts with the emulsion, hardening it into the screen. The excess emulsion is then washed away. A separate screen is created for each color. The screens are then placed in the printing machine. The discs pass underneath each screen and stop. A squeegee presses the appropriately colored ink through the screen. The disc passes underneath an ultraviolet light to cure the ink before the next color is applied. Thermal Retransfer (Digital) Print for Duplicated Media Using the relevant disc production software, the image is interpreted into a .prn file and then sent to the printer where the 4 colour panels or the black only panel on the ribbon are heated onto a transfer film, which is in turn applied to the disc and the image transferred across. The result is glossy, waterproof and well defined, with high definition and gradiented prints possible. Thermal Transfer Print for Duplicated Media Using the relevant disc production software, the image is interpreted into a .prn file and then sent to the printer where the ribbon is directly heated in the relevant positions by the strobe and the ink from the ribbon transferred directly to the disc. Less definition is possible using this method, although it is cheaper, therefore only text prints are recommended for this method. Inkjet Print for Duplicated Media Much like a desktop inkjet printer, the relevant disc publication software interprets the image and sends the information to the inkjet disc printer where liquid ink is transferred onto the print heads and then onto the relevant media, in a line-by-line print as the heads slide back and forth across the disc. Unless discs are then lacquered, the resulting print will smudge under a wet finger, however to avoid this happening and using chemical products, Dischromatics only offers Taiyo Yuden Watershield discs which absorb the ink after printing, providing a waterproof and glossy finish.
