Oki es7120 Reference Manual page 118

3. Take the new drum/toner cartridge out of the packaging box and shake it 7 to 8
times as shown in the diagram.
NOTE
> If the toner is not evenly spread out, the print quality may be reduced.
Also, if you did not shake the drum/toner cartridge well, there may be
operating noise or the interior of the cartridge may be damaged during
operation.
> Do not touch the surface of the photosensitive drum.
4. Place the drum/toner cartridge on a flat surface and pull out the seal horizontally.
NOTE
> When pulling out the seal, pull it out horizontally. The tape might break if
it is pulled out diagonally.
> After the seal has been pulled out, do not shake or bump the drum/toner
cartridge.
Daily care > 118