Four years ago we purchased 15x Prixma IP7250 printers. We initially replaced the inks with genuine cartridges but as the costs became substantial we used refills. Two years ago three printers started to malfunction so they were put aside. Later four others became faulty and we noticed some faults were identical. Later all the others introduced faults. We examined all of these faults and noticed that many were similar and the others also were similar. We then suspected these faults were introduced by the canon manufacturer in order to deter the use of refills. One of our staff started to look into the problem and we now understand the eprom was loaded with software that introduces a corruption if it notices the use of non Canon cartridges. If the software was initially downloaded from new and when a fault developed the eprom was reloaded with the initial software, the IP7250 started to work correctly! How can Canon justify the disposal of perfectly sound printers in this day and age.