The tiny and almost undetectable dots on a digital output product is referred to as "printer steganography". This is a restriction implemented in digital print machines to prevent forgery; strictly enforced by the manufacturers of Digital Output machines. We have no ability to remove the steganography.
The dots are printed with all colour Digital Output. It is only evident on a white background and most people will not be able to see this with the naked eye. It is intended to be unnoticeable and will not affect the overall look or colour of your design.