How to auto-update date to today's in Custom calculation script (Prepare a Form/Text Field Properties) for custom stamp

This may be a repetitive question, but I can't find the exact solution to solve this issue.

I'm currently using this code event.value = util.printd("name mm/dd/yyyy", new Date); for a stamp that is meant to sign off my work documents, but the stamp itself isn't automating the new date. I've had to go into the properties of the original file and reupload the stamp to the stamp palette on Adobe each day to update the date. Does this have something to do with the location of my saved stamp? If so, where should the stamp image be saved, so it would automatically update each day?