Thank you for your enquiry. It sounds as though ink nozzles in the printhead are blocked up with dried-up ink residue hence one of the colour inks is not flowing correctly. It's important to note that the blockage is not in the cartridge, it's underneath in the cradle where the cartridges sit, so putting in new cartridges will not solve the problem. Please contact our customer support team on 0871 288 4549 quoting your order number and we'll then be able to advise you further.