An alternative to a rubber or photopolymer plate, used as an image carrier in flexography.
A design roll consists of any of the various configurations of plate cylinder to which a thin (commonly at least J inch, perhaps thicker) layer of rubber has been applied. After the rubber has undergone vulcanization and cooling, the roll can be ground and polished to ensure that the surface is smooth and as close to perfectly round as possible (or having a total indicated runout of no more than 0.001 inch). The image to be printed is then engraved onto the surface of the cylinder using a high-energy laser which atomizes rubber in the non-image areas of the plate, leaving the image areas in relief. The height of the image above the floor of the cylinder can be varied in the engraving process, depending on the level of relief desired.
Laser-engraved design rolls are used for long pressruns, typically in decorative printing applications. The most important benefit of the design roll is its seamlessness; it can be used to print continuous images or solid-color backgrounds, such as those found on packaging, wrapping, and other such applications. The elimination of image distortion and elongation (a concern on flat, flexible plates mounted on a standard plate cylinder) is also an added advantage of the design roll. Design rolls can also be used in tandem with mounted plates for multi-color or multidesign applications.
See also Plate: Flexography.