© 2003 all rights reserved. This document and and photos can only be reproduced with the written permission of Terry Mehan.

A way around HP4100 fill problem. . .
As with so many Canon/HP cartridges there are always little obstacles to be overcome to be able to successfully remanufacture. The HP4100 isn’t the first (and nor will it be the last) cartridge designed to block access to the OEM fill hole. The second preference for pouring toner into a cartridge is through the mag roller aperture. The design of the HP4100 mag roller aperture prevents this as it is too small to give comfortable access.

Split hopper is one way around the problem of pouring toner into this cartridge, but a large number of small remanufacturers don’t use this method. An alternative is to cut away a small portion of the plastic combing that sits above the OEM fill hole, blocking access. This section of the cartridge does not perform any real function. The cogs that turn the agitator within the toner hopper do not rely on this section of plastic for support. When the cartridge is reassembled the cut area is covered by the cog assembly housing, so the end user will be unaware of the modification.

Method:
Imagine that the agitator cog is a clockface (photo 1). The plastic that needs to be cut away to gain access to the OEM fill hole is between approximately 5.30 and 8.30. It can take a deal of pressure to achieve the cuts.
(a) With a pair of side cutters, cut a small V in the right angled edge of the plastic combing at the 5.30 start position (see photo 2). This allows better access to cut across the surface of the plastic combing
(b) Cut across the plastic combing towards the centre of the agitator cog (see photo 3)
(c) Repeat cut at the 8.30 start point and remove plastic piece (see photo 4)
(d) The aim is to clear an opening to allow easy access to the OEM fill hole, but leave as much of the plastic combing as possible.

The HP4100 OEM toner hopper cap is also one that is difficult to remove without damage. There are as many methods for removing this as there are technicians. It is important not to damage the ledge immediately under the white plastic cap as this may allow toner to leak from the cartridge. We prefer to gently slide a fine screwdriver under the cap and past this ledge without putting any pressure on it. Use the screwdriver to place pressure inwards towards the middle of the cap (do not use the fill hole perimeter as leverage for pressure). Angle the screwdriver towards you and lift the cap up and out (see photo 5). You can use the side of the cartridge to help with leverage for lifting the cap out, but not the fill hole itself.

Use the rubber band technique (page 96, Recharger Magazine, January, ‘03) to hold the mag roller in position (see photo 1), then fill with toner (see photo 6) and cap off. Fit the mag roller end cap, mag roller axle bearing and drive cog, and the gear assembly and you’re done.

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