Monday I needed to replace the black cartridge in my HP Deskjet 3520, and the paper came out white! Two people worked on it, we followed all the trouble shooting suggestions, including a user's suggestion of mixing ammonia and water and drop it into the print head, then followed by prayer (I think that was in jest). No. It didn't work. My daughter and I checked all the deals on the internet. So I took all the cartridges (3 used, 1 unused) back to Staples which had a record of my purchase, got a $61 refund, bought a new $150 printer reduced to $95 with all sorts of discounts and coupons, bought a 3 year warranty (I usually don't but these only last about that long), and the whole thing with my $5 coupon from recycled older cartridges came to $54 for a new wireless printer/scanner/copier, an HP Envy (less than a package of ink cartridges if I'd replaced them). Yes, it's a racket to sell ink. Checked all the customer reviews, they were excellent. Now my daughter needs to come by and connect everything. I also signed up for the Instant Ink. HP tracks my paper usage and send me cartridges for $5 a month.