I have heard from friends of mine that using compatible inks in HP printers means that you are unable to use the ink monitor to find out the remaining ink. martd77 are you able to check ink levels on yours?
The thing you have got to remember with HP compatibles is that most if not all HP ink cartridges have a printhead built into the cartridge, now if these cartridges have been used before, recycled, cleaned and then re-filled, who knows how many times they have done this, the heads could be worn as they will be only really designed to last the life of the cartridge until it is empty. Basically HP ink cartridges are designed so that everytime you replace the cartridge you are also replacing the printhead.
correct you cant check the ink monitor but thats false anyway my original colour hp 351xl that i have in has popped up numerous times saying low ink level for the last month its still printing full colour a4 now,its not an accurate tool,i change my cartridges when they run out not when the utility advises me to. I repeat ive had hp for near 7yrs and used a mix of compatibles and originals,with few problems from only one supplier,and they have stopped doing them now anyway.
another thing to try is to purchase ink cartridges through your work. businesses usually get better discounts than us mere mortals because of their bulk purchases. now this method hinges on couple things: whether or not your boss is going to allow you to do so is the first and highest hurdle and the next obvious one is if you've got the same kind of printer as your office/will the business still get the same discount if you order an produc unrelated to the one they've been buying for the past however-long...anyhow, i work in a small office and am lucky enough to have a chilled boss who's allowed me to tag my ink cartridge needs onto the work order. we buy from caboodle, click here who have pretty good deals whether you're buying bulk or not...