Have you ever wondered how your Brother Inkjet Printer detects the ink levels in each cartridge? Unlike most inkjet printers which use a small micro chip the Brother Printer uses small infrared beams which shoot through the small window (see image to left) on your cartridge and determines how much ink is left. These infrared beams detect when the ink level changes in this small transparent window and people often fool the printer by placing small pieces of electrical tape over the window to make the printer think the cartridges are still full.
While this certainly works it is not advised because if you keep printing untill the cartridge runs completly dry you risk damaging your print head. Print heads need the ink running through them in the same manner as a car requires coolant to flow through the engine to keep it cool. When the ink runs out and you keep trying to print the print head can simply self destruct.
This is a fairly archaic form of detection however it seems to work reasonably well. This is one of the reasons why a Brother cartridge is so easy to replicate. Brother has used this method on their inkjet printers for many years however the latest Brother printers released have now followed other manufacturers and have incorporated a micro chip onto their latest cartridges.
When replacing a Brother Ink Cartridge you should always have the printer turned ON and it is best if you only replace each cartridge when the printer tells you so. Due to the simplistic nature of the infrared system if you replace a cartridge when turned OFF or even before prompted to it may not detect that it has been changed !