customer has print system. it enlarges the image even on the test print. the problem only happens when the copier sits idle for more than 20 minutes. any suggestions?

Disconnect the printer from the customer's hardware, unplug to reset it, and let it sit while turned on for a half-hour. If it still does the enlargement on an internal test print then the print system H is broken.

If it passes this test, some kind of ESC code is being sent to the printer to change to a lower print resolution by custormer's hardware or software. Not much you can do to fix that beyond trying to fully delete the driver and reinstalling from scratch to make sure it's done correctly.