anajet sprint crash

I am using an Anajet Sprin, everything seems working ok but after 3-4 prints the printer crashes. i have to unplug and restart and then crashes again after 2-3 printings. That didn't happen that often before. I am from spain and I bought the printer second hand "revised" from the oficial dealer, I had so many problems in the begining and they just did not help at all. So I coul learn from the forums how to fix problems. If somebody has had the same problem and has a solution that will be very apreciated, thanks in advance!