Laserjet Ink Cartridges HP LaserJet Ink Doesn't Adhear Properly, Why?

HP LaserJet ink doesn't adhear properly, why? - laserjet ink cartridges

I have an HP LaserJet 4, like me. I have revived over a year and recently restored. The impression seemed to be thinking outside of the ink ... Toner unequal pressure on the front and back (like when you run out of ink). So I baught a new cartridge and yet all the results of gray - as if my doctor was a gray paper. Then the oven toner is out? Apparently, the toner does not adhere. HELP!?