I would like to buy this printer. Now I don't know which toner number I need for this printer. I have a 10 year old printer also from HP but I still have 8 toner 305 A. I only bought two full sets from you in January. In the meantime, the old printer prints a brownish colour on the left side of the paper and the feed is no longer clean. I don't think it's worth repairing. Question: can I return the toner 305 A or exchange it with the toner for the above printer? Can I return the old printer (could solve everything with the store in St.Gallen). Thanks for an answer Greetings Jürg C.