I have a Brother DCP-J315 printer and a few weeks ago I started to get prints in blue when I selected black so I checked the ink volume and it showed almost full.I then took the cartridge out and it was blue not black so I checked the blue cartridge and that was blue..So bought some new cartridges I fitted the black and did a test print and it still came out in blue.And the test print had two blue prints no blackThere is also a problem with the yellow in that when I did a test print it only showed to lines so installed a new yellow cartridge and the ink volume was full but it still does not print right when I do a test page.I hope this makes sense.Any advice appreciated.