Check up on toner level, maybe you need to replace the cartridge?
More Supplies To Buy Together With Toshiba PK-04
More supplies for Toshiba TF 521, 551, 58 HN, 621, 651, 681, 831, 851, 856, 861 that you can buy together with Toshiba PK-04 Toner/Drum (Toshiba PK04):