Printer Faults - Marginal Marks or EdgeWear.

A succession of defects down the very margins of pages are likely to be print process rollers and particularly the OPC drum and Fuser which are directly exposed to the paper. The pattern suggested here tends to be characteristic of a fuser.

Continually dirty margins on a page are characteristic of a fuser wearing out. Fusers put pressure on the page. A typical page is 0.1mm thick and at the edge of the page the pressure density changes and slightly buckles and erodes the fuser parts, so they are likely to fail first in this position.

The fault is often visible in the fuser.

On hard rollers the wear pattern is visible a couple of millimetres in from the sides of the fuser. What looks like a build up of grunge at the sides of the fuser rollers will partly but not wholly remove when rubbed with a cotton bud.

On foil rollers the pattern is also visible, possibly more so. The material of the roller often looks a bit broken up at the sides. Don't mistake the black stripe at one side for wear - it's actually a brush-track allowing a little carbon fibre brush to contact a conductive layer in the fuser foil. Many foil fusers carry a voltage on the top, bottom or both rollers. However the sides of the foil are in constant contact with some guides and they do break down.

The cure is a new fuser. For some printers a roller or film - foil might be available. The fuser doesn't have to be changed the moment you spot edgewear unless the dirty margins are spoiling your prints too much.

Cleaning the Rollers.

If you are parsimonious or uncertain whether the fault really is edgewear, it may be worth trying to clean the rollers. Most fusers aren't particularly easy to dismantle (or rather they come to bits easily but don't go back together so well). We recommend cleaning them using a cotton bud and rotating the cogs by hand to get at the whole surface. Use a cotton bud, or a tissue to rub; use water, spit, isopropyl or meths as a solvent. DON'T whatever you do use a metal scraper and score the teflon - if you break the coat on the top roller it is finished. If the surface does seem to be damaged at the edges the problem is clear.

However do get a new fuser - the breakdown of the old one can be sudden.

Other Edges.

The fuser is most likely to exhibit edgewear because there is pressure along the paper margins.

AN OPC drum tends to show a similar wear pattern. In principle it doesn't actually need to contact the paper but in practice they come very close. There is a strong electrostatic attraction between a page and the drum which is normally resisted by the lack of flexibility in the page. The corners of the leading edge of a page can be deflected up and touch the drum. OPC drums usually have a tenth the life of the fuser so the effects aren't usually seen.

The pattern on an OPC resembles tyre marks. The margins tend to have more of a wave-like pattern. This might be the edge of the cleaning blade oscillating.

Transfer rollers and belts might take up the same pattern for similar reasons.

Similar Looking Faults.

Some patterns might look like edgewear but are not. For instance, toner adrift in the printer will tend to wind up at the sides of the print path where it might look rather similar to the onset of edgewear. If the contamination is light clean it away with a slightly damp tissue. If contamination is quite heavy see the section on