The original Brother LC-75
cartridge is made not to be refilled.
If you want to refill, you have to refill the LC-75 refillable cartridges
which are made to be refilled and are easy to refill as
You can purchase a set of Brother LC-75 refillable cartridges
LC-71 and LC-75 and LC-79 are
Printer ink and Refill kits for your Printer