There are four different alert modes that the Sharp MX-3100N displays when toner is either running low or is completely out. When in copy mode, the machine will display a row of four boxes when one or more of its toner cartridges has hit the 25% mark or below. When toner has gone down to the point where it is strongly advised to order another cartridge, a TONER SUPPLY IS LOW will also appear.

When it is time to change the cartridge because it has almost completely ran out, the message will change to read CHANGE THE TONER CARTRIDGE and when the cartridge has run completely out, the READY TO SCAN FOR COPY message will disappear. If one of the color toner cartridges has run out, the Sharp MX-3100N can continue to operate in black and white but if it is the black cartridge, the machine will not operate until a toner cartridge is changed.

Inside the boxes that appear when toner begins to run low are the letters Y, M, C or Bk, indicating yellow, magenta, cyan, or black, whichever of which requires changing. Remember which color or colors require swapping out, and open the front cover of the unit to begin the replacement process.

Each of the four toner cartridges will have one end displayed with a small release lever in it. Pull this lever on the proper cartridge and slide it out of the machine, keeping the cartridge level so as not to spill toner out of the end of it. Always recycle used toner cartridges through recycling programs.

Open a new toner cartridge to replace the old one and shake it around horizontally so as to spread the toner inside and loosen it. Also remove the plug off the end that is to be inserted into the machine, but be sure not to spill toner out of the now open end.

Insert the new cartridge into its proper slot, as it will not go into any others. Be sure to slide the cartridge all the way into the unit until it snaps into place. If there are no other cartridges to be changed at this juncture, close the front cover of the machine and resume operation.

When a staple finisher is attached to the Sharp MX-3100N, its staple cartridges will often require replacing. When a message appears on the LCD screen indicating that the cartridge has run out, begin the replacement process by opening the cover to the finisher.

A lever is located on the left side of the finisher. This must be pressed on to slide the unit to the left, all the way until it cannot move any further. A small lever found behind this panel will, when pulled, release the staple case. The case will first drop open, and can then be removed by pulling OUT and to the RIGHT. The empty staple cartridge can be easily popped out of the staple case, and then replaced with the new one. Replace the staple case by installing it in the reverse direction, and then slide the finisher back over to the right, until it locks into its original position. Close the cover and continue stapling.