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1O Things You Should Know

7 Jan, 2008 By: Jon Mueller imageSource

1O Things You Should Know

The list on fusers is meant to be a memory jogger about simple things that
may be overlooked even by the most experienced technician who gets rushed by
having too much to do, but too little time. Over the years, printers have
evolved into highly complex, networked, high-speed machines. However, they still
retain the core group of parts and other “little things” that can be frustrating
when trying to service them.

The next time you hit a fuser error bump, I hope the following input helps
you “defuse” many of your frustrations:

1. There goes the heat

If you receive a 50 service error, or equivalent, the fuser’s heat source
may have burned out. This is the equivalent of walking into a room, flipping on
the light switch, and the light bulb burns out. There is no foolproof way to
prevent or predict when the lamps will burn out in either OEM or refurbished
fusers. The fuser’s necessary heat comes from two primary sources:
halogen/quartz lamps or ceramic elements. Also, check shipping. Though it is
rare, shipping may weaken or break the filaments in the lamps or cause the
ceramic to crack.

2. Where’s the pressure?

If proper pressure isn’t applied, the fuser can’t function. A sign that
there’s a lack of pressure is an improperly fused page. The pressure the fuser
needs comes from the LPR (lower pressure roller) and springs. The springs in the
fuser put pressure on the fuser’s lower pressure roller. Rollers are available
in many different   forms:  foam, solid  rubber, multi-layer coated and other
materials. Some fusers can work with either a solid or foam LPR. The type of
material used by the OEM is specific to each printer.

3. Upper fuser roller (UFR)

Just as it takes two to tango, it takes two rollers to make a fuser function
properly. If the LPR isn’t the issue, it’s possible the upper fuser roller (UFR)
is. Upper fuser rollers come in many types. The most common is an aluminum tube
coated with Teflon, or a similar material, not unlike what you would find on
your pans  at home. The way the coating is applied and the cure temperature of
the coating are critical. If the coating is nicked or scratched, toner can
accumulate on the upper fuser roller and transfer  print defects to the page. 
It’s  normal for separation claws to make marks or thin lines on the roller.
This can happen even after a page or two has printed. In this case, the coating
is not damaged but a line does appear on the roller.

4. Check the fixing film/sleeve (and don’t believe the myths!)

Another fuser component that may be the cause of a fuser malfunction is the
fixing film or sleeve. If the sleeve isn’t turning properly, the paper can’t
move through the printer to its final printed state. There are two common myths
about fixing film or sleeves. One myth is that the sleeve must turn when the
main drive gear turns. When examining the fuser, as you hold it in your hand,
the sleeve may or may not turn. This does not necessarily mean your fuser is
defective, since fixing film fusers rely on the paper’s thickness to provide the
friction needed to rotate the sleeve. Another myth is sleeve color determines
quality.  This is untrue.

5. Check the fuser’s flags or sensors

All fusers have sensing levers (or flags) that must move freely in order to
ensure proper printer function. These flags tell the fuser or other components
inside the printer what to do. Like traffic cops who use flags to direct cars,
sensing levers (flags) guide the paper through the printer, including the fuser.
When a traffic cop’s flag doesn’t work, you get a traffic jam. In a printer, if
a flag doesn’t work properly, you get a paper jam. You know them as “13.xx paper
jams” or “2.xx jams” in Lexmark printers. Depending on the type of error you
receive, you can determine which flag is causing the problem. Flags can be
easily inspected prior to the fuser’s installation by making sure they are
secure and that they move freely. In many cases you can simply snap or lightly
bend the flags back into place.

6. Levers: The ups & downs of the fuser

Some fusers have levers or spacers placed in them to establish a gap between
the upper fuser roller and the lower fuser roller. The levers are meant to
prevent flat spots from developing and in some cases, for printing on envelopes.
When they are on the envelope setting, toner will not fuse properly on normal
paper thickness. This is a very common complaint that’s easily solved. It only
takes a second to check.

7. Adjusting the printer’s temperature

Some printers have the option of making temperature adjustments to optimize
printing for different media types and paper thickness. At companies like Parts
Now!, we commonly hear from field techs that say “I never used to have to turn
up the fuser temp.” If you’ve never had to do this in the past, consider
yourself lucky. But with today’s increasingly sophisticated printers, you may
encounter this in the future. Sometimes fusers will properly fuse the toner to
the paper without these adjustments, but it’s important to know where they are
and how to adjust them for optimum printing quality.

8. Help! The fuser service error is still there!

Another call we receive is, “I put in the new fuser and it still has the
fuser service error.” This may happen with HP 4+ and older printers. If this
happens, it may be a good time for you to take a coffee break, or quick lunch
break and check back in a little while. The printer may need to time-out or
power-down for up to 20 minutes after the fuser service error appears. If you
did not switch the printer off and you installed the new fuser, the machine will
keep displaying the error message. The printer needs up to 20 minutes  in a
power-off condition in order to clear out the error.

9. Inputs and Outputs

Other key parts on fusers are the paper input ramps and output guides (you
might know these by other names). These components allow the paper to enter and
exit the fuser. They should periodically be checked for any foreign material
that may be inside the printer that may end up in the paper path in front of the
fuser. The common term “paper-thin” was probably born out of this situation. 
The foreign material need only be thicker than “paper-thin” to cause a hang-up.
Check the input ramp for a small nick or burr. While the fuser may have worked
in our test printer, after shipping and cleaning, alignment may be slightly
different and could cause a jam. In most cases, you can simply remove small
burrs with your finger. It’s also possible that the exit guides or rollers
shifted during shipping or while in the printer. Simply snap them back in line.

10. Check to see if it’s time to shift gears

All fusers have drive trains (small gear boxes) that must mesh with other
gears inside the printer. Conduct a quality inspection to ensure proper gear
function in its refurbished fusers prior to shipment. But the fuser relies on
proper alignment with other gear assemblies in the printer. If the printer’s
existing gears are severely worn or seized, the newly installed fuser drive
assembly can be damaged. To avoid this mishap, run a quick check of the old
fuser for any gear damage. Make sure all other gears on the assemblies are
functioning properly prior to installing the refurbished fuser. This can prevent
damage to the newly installed fuser & ensure proper printer function once it’s

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