HP Laserjet 3050 all-in-one - prints but won't copy

I have this HP Lasejet 3050 for 6 years but won't copy. It print reports and from computer too. No problem but When I copy b&w original then copy comes all solid black. Please help

P.S. This thread has been moved from Printers - LaserJet to Multifunction and All-in-One. -HP Forum Moderator