I have a Brother HL-L2320d printer that I am having problems printing pdf files. It prints them okay, but there is a gray grid behind the print. It has all kinds of write marks on the gray. There are also numbers and letters. I have tried different computers connected to the printer without a difference. I have also tried different pdf readers and it makes no difference. I can print from Word without problems. It is only pdf files where I have a problem.