After the seal is installed, the hopper should be checked for leaks by tapping it on a table at different angles, and slapping it on the sides. If there is any indication of leaking, it should be re-sealed until it no longer leaks. After sealing, since there is no way for toner to get to the magnetic roller until the seal is removed. Because you must post test the cartridge, it is a good idea to save a little toner from each fill, to use for priming the mag roller for post testing. Filling A pre-measured bottle of toner, and a funnel is the easiest method of filling.
Different cartridges get different types and amounts of toner.
When the desired amount of toner is filled, the hopper cap should be immediately replaced, and the edges of the hopper cap should be blown off with compressed air in a hepa-filtered suction chamber. Be sure to save a little toner for priming the mag roller. The hopper should then be checked for leaks as described in the previous section. After tapping and slapping, turn the magnetic roller to see if any toner is on it. If your hopper is leak free, the magnet roller should be clean.