Future of Waterless Printing, 1996 New Printing Technologies Symposium Proceedings

John Zenner

Toray Marketing & Sales

Waterless printing is not an invention of the 1990’s, but is actually a 27 year old printing process. Waterless printing was developed by two companies working separately in the late 1960’s, 3M and Scott Paper Company. They invested $25 million 1969 dollars into the development and marketing of Waterless, or Dry Offset as it was known then, printing to develop a revolutionary printing process. Unfortunately, they did not have the support systems needed to print Waterless, causing the process to fail. In 1972, Toray Industries of Japan, purchased the patents from both companies and re-developed the Waterless plate. This process took 5 years and in 1977, Toray introduced the positive working plate (TAP). During the 1980’s, Toray introduced the negative working plate (TAN) to the United States. Toray continues to enhance its product line to meet the requirements of the ever changing printing industry. Currently Toray has 5 different positive plates and 1 negative plate with another in development. The positive plate will print up to 900 lpi with a resolution of 1% and 99% dots and a 8 microline. The negative plate will print up to 300 lpi with a resolution of 0.5% and 99.5% dots and a 8 microline. Run lengths on a positive plate can be up to 1,000,000 impressions, while the negative plate is rated at 200,000. The run length can be varied either way depending on the hardness of the substrate being printed on. To properly comprehend Waterless printing, a full explanation of the plate and system is required. The printing plate is completely different than that of a convention printing plate. A conventional printing plate is a grained aluminum substrate with a lacquered surface. This lacquered surface represents the image area, imitating a raised printing surface, allowing the dampening solution to create the non-image area. The Waterless plate is a layered plate, using an aluminum substrate, photopolymer image area and a silicone non-printing area. The silicone surface is 2 microns in thickness. Conventional plate media is used for exposing the plates using UV light. The UV light ruins the adhesion between the silicone and the photopolymer layers. Exposure times are in direct proportion with those of conventional plates. Processing is done by means of a special processor using three separate chemistries. The plate first passes through a pre-treatment chemistry which, depending on whether a positive plate and chemistry or a negative plate and chemistry is being used and for this purpose a negative plate will be used, loosens the silicone in the image area and completely bonds the silicone to the photopolymer layer. Development is done by a rotating oscillating brush using tap water to remove the silicone from the...