Replacing Fuser Film Sleeves

Film based fusers are quite common and all HP and Canon printers made in the last ten years use them. In normal use the film lasts well - typically about 100,000 pages in light duty printers like the Laserjet 6L and 200,000 pages in machines like the Laserjet 4200. At some point the film will fail - all prints will have dirty edges or lense-shaped areas of toner on the page will not be properly adhered. Quite often bits of broken film will emerge with the last sheet of paper.

If the printer was a low cost home model complete fusers are relatively expensive, so if you don't want to buy a new printer (or have spare cartridges that would be wasted) then the best answer is to fit a new fuser-film.

If the printer is an office model then the answer that will give least trouble is to buy a manufacturer's original new fuser. Refurbished fusers are a bit more prone to giving teething trouble - which gives some idea that replacing the film isn't easy. However if you want to cut costs, or have a large fleet of printers where repair is part of the daily routine then new fuser films might be the right answer.

To repair a fuser you need

• A new fuser sleeve for the right model - HP use three different types of film: polymer based (most older models), metal based (fast models) and rubber coated (colour and newer printers)
• A small quantity of the correct high temperature grease (e.g. code MSPGREASENM [polymer films], CARBAFLO10GM [polymer and metallic films] or MSP2828 [metallic films] available from mindmachine.co.uk)
• Patience - especially for the first of any model

Check the fuser heater for continuity before buying a fuser film sleeve. Heaters aren't so readily available as films. If the heater won't work there is no point in replacing the sleeve and they aren't returnable because a handled sleeve isn't re-useable.

Fitting the Sleeve

Remove the fuser from the printer. Dismantle the fuser observing the orientation of parts. Take care with the plastics - they are usually ABS but with a lot of glass fill to handle the high temperatures of the fusing process.

Note the black stripe on the existing fuser film (if it has survived) - it should line up with a carbon-fibre brush. The new film will need to go on the same way round.

Check the heater element. There will be an electrical connector, the silvered ends under this should not be charred (they may be tarnished but there should be a good connection). Check that the heater isn't buckled or damaged.

Check electrical continuity - something like 100 to 200 Ohms is typical (it depends on whether the fuser is a 110 Volt or 220 Volt model). If parts are broken or the heater doesn't have continuity there is no point fitting the film sleeve until this is rectified .

Clean the existing high-temperature grease off the fuser heating element. The heating element itself is normally white ceramic with two black tracks (the heater) on a metal support. Use a tissue dampened with isopropyl alcohol and a cotton bud to reach any dirt in crevasses. The new grease needs to be clean to make good contact between heater and film.

Use a spatula or plastic strip to apply the grease. Don't use a screwdriver tip, it may score the heater elements. For an A4 printer apply about 1 gramme of grease from the container in about 20 small dots along the heater. For an A3 printer increase this to 1.5 to 2 grammes. Use double the amount of grease if the printer has a metal sleeve.

Spread the grease evenly along the surface by wiping it with the spatula.

With clean hands take the new film sleeve out of any packaging. Put the sleeve over the metal core and the heater in the correct orientation so that the conductive stripe will match the brush. Avoid getting any grease onto the outside of the sleeve or pushing the grease down the heater - try to put the sleeve on the core without touching the heater.

Turn the sleeve several times by hand until the movement is smooth. The grease is quite thick at room temperature but the sleeve should turn quite freely.

Reassemble the fuser and try it out. If the printer manages 100 pages then the job seems good.

Support on Fuser Films

Fusers can be fairly complicated items.   Don't try to repair a fuser unless you have a good idea how it works. We won't be able to talk you through the rebuild process.

HP and the other printer manufacturers do make some fuser films available but at prices that offer little advantage compared with a refurbished fuser.

We buy our fuser sleeves from UK distributors and they do their best to source them from good suppliers. However there can be problems. For instance there are more than 40 Chinese companies claiming to make fuser films and there is little to distinguish good from bad.

Printer manufacturers don't make the specification of the films or lubricant they use available for obvious reasons - they would prefer people to buy their own branded spares - and generally they would prefer to sell new fusers because that gives the least trouble. Manufacturers don't issue "authorised part maker" badges. We expect the distributors we use to own-up if they get a bad batch of sleeves or lubricant but they are unlikely to give a refund. Fuser sleeves are like electrical and car engine components - you buy and use them at your own risk.

If you want a reliable repair buy a manufacturers original fuser. Risks are slightly higher with refurbished fusers. Fuser sleeves are a cheap alternative.