1. Home

     When in the home position the pad is located above the object to be printed, and the ink cup is located directly over the recessed image area in the cliche. The recessed image area is only microns (millionths of a meter) in depth.
   
   

2. Doctor Out

     As the cliche actuates out from under the ink cup, (or in some machines the ink cup actuates over the surface of the cliche) the sharp edge of the ink cup (commonly referred to as the doctor ring) cleans (doctors) the surface of the cliche clean, leaving ink only in the shallow image area. Once the ink is exposed to the air, solvents immediately begin to evaporate, causing physical changes (increase in surface energy) in the ink making it "tacky" on the surface.
   
   

3. Pick-Up

     The pad is evenly compressed onto the surface of the cliche and then lifted away. The physical changes that occured in the ink film as a result of solvent evaporation allow the ink film to leave the cliche and adhere to the silicone transfer pad.
   
   

4. Doctor In

     As the cliche actuates back to it's original position (or in some machines the ink cup actuates forward over the recessed image area) the outside layer of ink (which used to be the bottom layer when the ink was in the cliche) continues to undergo physical changes, ideally becoming a cohesive layer, tacky on the outside surface.
   
   

5. Transfer

     The pad is compressed onto the surface of the object to transfer the image. Even though the pad is compressed considerably during this step, the contour of the pad is designed to roll out onto the object rather than compress flat against it. This enables the pad to evacuate all of the air from between the ink film and the object as the image is tranferred. Because the pad is made of silicone, the ink layer wants to leave the surface of the pad and adhere to pretty much any object that has a higher surface energy than silicone.
   
   

6. Return

     The pad returns back to the Home position. When all of the variables in the process are correctly controlled, all of the ink will have released from the pad during image transfer, and the pad will be ready for the next print cycle.

View Animation of Functional Principles