Canon LBP6000, HP LaserJet Pro P1102, M1132 and M1212 Pick-Roller Change.

These printers look very different but are all based on the same print engine, so the pickup roller and pad are the same - albeit with some changed part numbers.

Paper feed problems are likely to be solved by:

• not overfilling the paper-tray.
• checking the paper guides are guiding but not gripping the paper
• ensuring the paper up against the feed roller at the back of the machine.

Paper is loaded into the tray at the bottom front of the machine. Inside the machine the paper stack should be under the pickup roller.

When the pickup roller turns it engages with the paper and pushes one or more sheets back and up. If paper fails to move at all or is slightly scuffed on its leading edge but does not feed then suspect the pickup roller.

The paper hits the separation pad. If more than one sheet was pushed off the paper stack then the lower sheets will come into contact with the pad and friction with it's rubber surface will stop them travelling. Only the top sheet which is being driven by the soft textured rubber of the pickup roller will be able to move forwards. If several pages do feed:

• the tray may be too full, so there is too much pressure from the roller.
• sheets of paper may be stuck together by damp or by bad mechanical guillotining.
• the separation pad rubber has probably hardened and is too slippery.

If sheets often don't feed or if the last sheet does not feed the pad may have developed an indentation so it has too much grip on the paper.

Paper then hits the registration station, a pair of page-width rollers that are static at the moment it arrives so the paper straightens up. When the page image is about to be fed to the laser unit these rollers start to turn and the page goes past the leading edge sensor - if it doesn't arrive the printer will stop and give a paper feed error.

The paper goes between the cartridge drum and the transfer roller. The voltage difference between them pulls the image made in toner powder onto the page. If the voltages are wrong due to a bad contact on the cartridge or a buildup of toner on the roller then paper can deflect and jam at this point.

The leading edge of the page now passes into the fuser, which has a rubber pressure roller and a ceramic heater surrounded by a non-stick film. The heater raises the toner to its softening point and the pressure forces the tacky material into the paper. The result is a long lasting print.

If the leading edge of the paper doesn't arrive at the delivery sensor in time the printer software assumes something bad happened between the cartridge and the fuser and stops the machine.

Fusers are a trouble spot in printers because the mechanism involves heat and pressure. For instance if people put inappropriate transparency material or labels through the printer they can melt or get stuck in the fuser. Subsequent pages will probably jam or concertina at the fuser entrance. The fuser film itself will ultimately degenerate, bits of grey material are likely to come out into the delivery tray.

There can be a problem distinguishing between a fault in the late stages of printing one page and the early stage of the next. If the printer often stops with one page half-way into the delivery tray try sending a dozen single pages and see where a jam occurs. If it is before registration the problem is likely to be pickup. If the paper stops in the fuser look at the fuser itself, the delivery rollers and the delivery sensor.

Changing the Roller

The feed roller is visible in the bottom of the printer with the cartridge door open and the cartridge removed. The roller actually sits in a cradle, held in place by a pair of bosses and clips on either side. The clips are highlighted in green in the diagram below although in practice they are just the white plastic of the cradle.

The clips push outwards to release the roller, it then rotates up and out. The boss and clip are highlighted in purple in the second diagram.

It may be necessary to push the roller round a bit to get at the clips.

Canon say not to touch the rubber of a roller; this is, of course, impossible. Greasy fingers will de-nature the rubber. Try to handle the rubber surface of the roller as little as possible and use clean hands - or wear a disposable glove.

Don't touch the transfer roller unnecessarily. It is conductive rubber and a grease mark on it may cause drop-outs and uneven print.

Because paper feed faults can be frustrating to deal with it is worth examining a roller to see if it is likely to be the cause of a problem. A good roller has a textured surface. A used roller will have some shiny spots.

Roller texture is sometimes spoiled by a hard deposit on their surface. This will come off in soapy water - make sure the roller is fully dry before putting it back in the printer. Isopropyl alcohol cleans the rollers as well, although it may spoil the plasticiser its worth trying if you want to get a bit more out of a printer whilst waiting for a spare.

The roller seems to appear under several part codes:

HP Documentation says the roller is RL1-2593-000CN.

HP also have a kit with a Pickup roller and Instruction sheet - CE841-67901.

Canon distributors say RL1-1497-000 which is the roller used in the HP P1505, P1566, P1606, M1120, M1522 and M1536.

The parts are probably identical. It isn't unusual to find Canon/HP producing the same part under different numbers. However they can also produce slightly changed parts with locating pins in different places.