I have had an HP Officejet Pro 6230 for just over a year. It is used on a daily basis for our small business. I use HP cartridges but I have constant problems with the black ink not printing. I regularly clean the print heads but that is now making no difference, it is still streaky and patchy. The printer was replaced when a few months old for the same problem now I am unable to print a decent copy. I have also just bought two sets of new cartridges from HP. Having read that this is a known problem with this model, why has it not been sorted. I need a printer that works for my business and this one is just not up to the job.