Duroweave Premium Dampening and Roller Covers
The Duroweave Difference
Duroweave brand dampening materials are designed to meet the demands of quality conscious printers. Our use of premium yarn and state-of-the-art production methods ensure that our products enhance the operation of the press, the productivity of the press operator, and the quality of the finished printed product.
100% Synthetic Construction:
We use only quality rayon yarn in the knitting of the pile or surface of our dampening products. These strong and yet pliable man-made fibers are continuous in length from beginning to end. Because rayon yarn consists of continuous length filaments there can be no separation of fiber and the resulting lint or quality problems. The benefits are higher print quality and more efficient press operation.
The yarn in lower grade cotton covers consists of short lengths of cotton known as "staples". These fibers are loosely spun together to create a continuous length of yarn. Unfortunately, these fibers often become detached from the cover and end up on the printing plate resulting in lower print quality. The problem is especially noticeable in areas of solid coverage, headline type, and halftones. This fiber contamination also builds-up on the rollers impeding the proper transfer of ink.
Printer's Repair Parts is the only manufacturer in the USA producing sheared surface dampening covers. All of our dampening products undergo an additional production step which further enhances their performance.
All Novatech Brand Dampening Covers are sheared for improved water receptivity
After the cover is knit, it is turned right-side-out to expose the loop surface. Then it is passed through a shearing machine which precisely cuts open the tops of the knitted loops. The resulting plush, velour-like surface provides even plate contact, increased water receptivity and balanced distribution.
Finer Denier Yarn:
Yarn is manufactured according to a specification known as "denier". The higher the denier rating, the greater the number and the finer the filaments a which make up the strand of yarn. Our products are knitted with 200 denier yarn meaning there are 200 individual filaments in each strand. This high fiber count offers increased water absorption and transfer as there are more individual filaments to wick the dampening solution. Most competitive covers use only 120 or lower denier yarn.
We not only use finer denier yarn but also knit more strands of yarn into our covers to construct a dense, water receptive surface. This increased surface density allows a balanced film of water to be transferred to the plate very quickly. The result is overall improved print quality with a sharper dot in halftone reproduction. Since the object of offset lithography is to print while using the least amount of water and ink, our covers actually assist press operators in this goal. Many pressmen report that they can actually reduce the water setting on their dampening unit when running our covers.
Ease of Cleaning:
All dampening covers will attract a certain amount of ink during normal use. The ability to easily clean this ink off the surface of the cover can result in improved performance and extended cover life. Cotton covers are a poor choice for washability as offset inks are very difficult, if not impossible, to clean by any method.
Novatech brand covers clean easily for two reasons: One, our sheared surface is free of fiber loops which commonly trap ink pigment, and, Two, we only use rayon yarn, a synthetic fiber which naturally releases ink and cleans well.
Our covers may be cleaned with the use of ordinary tap water. By simply spraying the roller with hot water under pressure more than 98% of the ink can be flushed off. The benefit is extended cover life and reduced cost. It is not uncommon for Novatech dampening covers to last 2 to 3 months.
Improved Roller Fit:
The base yarn used in the knitting of all Novatech covers is known as "PVA" or polyvinyl alcohol. This yarn has the unique ability to shrink dramatically when wet with water for the first time. This feature results in an extremely tight fit of the cover to the roller. It eliminates bunching, twisting, or creeping so often associated with cotton covers which often stretch with use.
Additionally, our products have the highest shrink ratio of any cover on the market. An advantage of this construction is a wider range of roller diameters that can be fitted by one size cover. For example, one of our popular roll sizes will fit the Heidelberg GTO, KOR, KORA, KORD, MO, S series, and Speedmaster presses. You would need at least three different sizes of some competitive covers to properly cover the rollers on these presses. This versatile sizing results in lower inventory costs in many cases.