Even if you use the best equipment and products, the printed result is determined by a single point in time – the precise moment when the printing supplies and blanket come into contact with the substrate. Is it not your job to make sure you have the best printing blanket?
Offset printing blankets are designed to withstand heavy use. Printers want a blanket that can transfer a high-quality image from the plate to the blanket and work quickly with various papers. They are looking for a blanket that can withstand chemical changes such as solvent, fountain solution, and ink.
WHAT HAS OFFSET PRINTING, AND HOW DOES IT WORK?
The method is based on the fact that certain inks and water do not mix. Text and images are first transferred to plates using various techniques, the most common of which is a chemical process similar to film development. The plates are then alternately painted with water and inks, with ink adhering to the image areas and water adhering to the rest. The images on the plate are then rolled over or covered by a rubber sheet known as a “blanket.” Henceforth, the image is transferred to the paper stock from the blanket. The process is then repeated for each color separately.
Colors are applied as microscopic dots blended in different proportions to give the appearance of different shades and hues to the human eye. The plate does not transfer ink directly onto the paper at any point in time, hence the term “offset.”
LET’S ANALYZE THE TWO MOST IMPORTANT ELEMENTS OF AN OFFSET PRINTING BLANKET
The Face of the Blanket
The surface layer, or part of the blanket that comes into contact with the plate and paper, is more commonly referred to as the blanket’s face. It is designed to transfer images as sharply as possible. To accomplish this, blankets are made with a smooth surface. However, if they are manufactured too smooth, the ink may have a more challenging time releasing onto the paper. Hence, manufacturers strive for a balance.
In addition, the rubber compound on the compressible layer must be resistant to offset press chemicals. The blanket is constantly pushed with solvent, ink, and fountain solution. These chemicals must not be able to penetrate the rubber. Moreover, it must not swell, shrink, or crack as a result of the reaction. UV inks, for example, will cause the rubber to swell. You must order the appropriate blankets based on the chemicals you use.
The Body of the Carcass
Everything sandwiched beneath the surface layer is referred to as the carcass. The offset printing blanket has two layers: a fabric layer and a compressible layer.
The fabric layer is made up of right-angle woven strong quality thread. A warp or weft is the term for each direction. Because the warp is the strongest, the blanket is constructed so that the warp wraps around the cylinder in a circumferential direction. When this direction is tightened against it, it receives the most stress.
In comparison, the blanket is subjected to very little lateral stress.
A sponge-like layer is included in the compressible blanket’s design which is a compressible layer. This layer can be made up of closed or open cells.
The open-cell design of the blanket allows air to flow freely throughout it and has its uses. On the other hand, closed-cell is the more popular design because it retains its compressible state for a long and has a high resistance to smashing over time.
A PIECE OF ADVICE
If the printers are operated by experienced personnel, the offset process produces more consistent results in terms of print quality and printing supplies.
Always choose your printing supplies from a reputed brand that offers a 100% guarantee and comes with full technical support, including on-site assistance, if needed.