Control of Coating Thickness
Original Publication Date: 1983-Nov-01
Included in the Prior Art Database: 2005-Feb-07
The thickness (or gloss) of the layer of magnetic recording ink, which is placed on a flexible substrate by the use of the coating head (for example, the one disclosed in U. S. Patent 4,345,543), is closed-loop-controlled by the use of sample-and-hold techniques which are related to the time period which expires between the step of coating the ink and the later step of measuring its thickness (or the step of calendaring the dry coating and the later step of measuring its gloss). The desired characteristic (thickness or gloss) is represented by a DC voltage. A servo system 18 utilizes feedback of a control voltage 24 which is summed with a deviation voltage 17.