System and method for forming an image on a substrate

Abstract

A scanning laser having a wavelength compatible with a coating binder so as to cure it as the laser scans and irradiates the coating on a moving web. A system and method for curing flakes by providing a scanning laser which scans across a moving coated substrate in a magnetic field allows images to be formed as magnetically aligned flakes are cured into a fixed position. The images have regions of cured aligned flakes. The scanning laser cures the magnetically aligned flakes within it region it irradiates. Alternatively an array of lasers can be used wherein individual lasers can be switched on and off to fix irradiated coating as a moving web is moved at a high speed.

What is claimed is: 
     
         1 . A system for coating a substrate comprising:
 a station for moving a substrate at a speed of at least 25 ft/sec along a path;   a coater for coating the substrate with a plurality of coating regions each coating region for forming a separate visible image formed of at least two contrasting regions of magnetically alignable flakes within a binder;   a first magnetic field generator positioned about a portion of the path for generating a first magnetic field for aligning magnetically alignable flakes within a each coating region as the substrate moves along the path; and,   one or more lasers for providing one or more laser beams; and,   a controller for controlling the one or more lasers to irradiate a plurality of locations on the substrate along a direction across a downstream direction of the path so as to cure lines of the coating across the substrate in succession as the substrate is moving and wherein the length of the lines vary in a predetermined manner so as to form one of the at least two contrasting regions of magnetically alignable flakes.   
     
     
         2 ) A system as defined in  claim 1  wherein the controller is programmed to control the speed of the substrate and a sweep of the laser beam to ensure that the length of the lines vary in the predetermined manner. 
     
     
         3 . A system as defined in  claim 2  wherein the controlled speed of the substrate and the sweep of the laser determine an angle between the lines and a line coincident with the path. 
     
     
         4 . A system as defined in  claim 1  wherein the controller is programmed to vary the speed of the substrate along the path. 
     
     
         5 . A system as defined in  claim 1  wherein the controller is programmed to control the amplitude of a sweep back and forth of the one of the one or more laser beams across the downstream direction in conjunction with controlling the speed in which the substrate moves along the path in the downstream direction for forming the visible image. 
     
     
         6 . A system as defined in  claim 5  wherein the controller is programmed to control the speed at which the laser moves back and forth across the path. 
     
     
         7 . A system as defined in  claim 1  wherein the controller is programmed to control the amplitude of a sweep back and forth of the one of the one or more laser beams across the downstream direction and to control the speed at which the laser beam moves in the back and forth direction, and wherein the substrate moves along the path in the downstream direction at a fixed speed for forming the visible image. 
     
     
         8 . A system as defined in  claim 1  wherein the one or more lasers is an array of lasers and wherein the controller is programmed to switch the lasers on and off in a predetermined manner as the substrate is moved along the path in the downstream direction.