Experiences using the mirroblade coater in fine paper production

The Mirroblade® technique for simultaneous two-sided blade coating has now been in mill operation since more than two years on two paper machines. The coater uses a new blade type, with soft-tips. The conclusions so far are that a) paper can be blade coated on both sides using a single coater, b) the soft-tip blades give a fiber coverage that is superior to that of conventional blade-coated paper and c) the lifetime of the soft-tip blades is long, averaging 5-7 days. Two-sidedness of the sheet is no problem and is controlled in a number of ways including using different solids content of the coating color on the two sides. Runnability was somewhat poorer after the rebuild to the new coaters. It has steadily improved since then and is now essentially equal to previous runnability. Finally, results trom a pilot coater are shown, and they indicate that a wide range of coat weights can be applied in this type of coater.