Troubleshooting Laser Printer Revision
Posted 19 January 2008 - 02:41 PM
there seems to be quite a confusion about troubleshooting a laser printer
I know its like a reverse of how a laser printer works, but suppose each of the components in the laser printer fails
I know for the A+ 2006 CompTIA will ask like:
blank paper, dirty output, ghosting,
vertical white lines/missing lines/blotchy print/white streaks;
white lines/white stripes;
vertical black or white lines/a repetitive pattern of printing defects such as an identical smudge every 2 in/ repetitive small marks or defects/ repetitive pattern of speckles or blotches;
spotty print appear at regular interval;
a small crack, chip, nick, scratch or groove in the drum;
garbage output/garbled text;
incomplete char on laser printed transparencies;
portion of the page does not print/ slow print;
warped, overprinted or poorly formed char
the A+ texts, A+ wiki, cheat_sheet all give differ causes & differ explanations & differ solns
I am so confused
which exact components caused it & explanations & exact soln?
I know someone out there was asking the same question but was afraid to ask so I volunteer as a guinea pig
Posted 20 January 2008 - 05:27 PM
When I was in the army, I was a medic and had to (troubleshoot) triage patients in a few seconds based on their blood pressure, wounds, vital signs, etc and these things constantly change (and could mean life or death if you got it wrong or right). The great thing about hardware or software is it has more of a constant, meaning that you can limit the problem down to 3-4 possible good causes. I guess what I am getting at is if you know how something works and what processes it goes through, you can narrow down the problem and on the exams you are given 4-5 possibilities and you can more than likely rule two of those out easily then you have two to choose from and will be able to pick the right one from knowledge of learning how it works and what parts are involved at what process of printing.
If you study guide is up to date and covers the objectives I would go with what your book states.
Hope this helps some and good luck on your exams.
Posted 25 January 2008 - 11:52 AM
in other words, I like to know ahead of time of what to expect on the official exam like
if CompTIA asks me question about white stripes on a laser printer, what is the correct ans cuz A+ texts all give me differ ans and I like to know what is the correct ans instead of guessing if narrow down to two possible ans.
on the forum wiki A+, it started out OK but then on the next paragraph things got screwy and I got lost and confused about the laser printer troubleshooting and I request to clear all of them up ASAP.
I request to be fully prepared.
Posted 02 February 2008 - 06:45 AM
yes I have gone to webschool and one of the blogs and does seem a bit confusing on who is actually right
I will post when I have the chance on what was previously was mentioned. It seems outdated.
Posted 02 February 2008 - 06:53 AM
I request clarifications/corrections/omissions if necessary because to me it seems a bit outdated & no one seem to update it lately.
This was taken from the A+ Wiki
Laser Printer Problems
1. Blank Paper: out of toner, print diagnostic page if toner is there
2. Dirt Printouts: get the printer cleaned (fusing mechanism gets dirty)
3. Ghosting: imaging drum not fully discharged, cleaning blade worn-off
4. Black Paper: drum is not being charged. The primary corona is broken or not making good electrical contact.
5. Toner Falls off Paper: Fuser assembly is malfunctioning and is not binding toner to the paper.
6. Clumping toner - Humidity is too high. (recently found this one)
Aside from what was already mentioned,
When a drum gets old it can cause a dirty background which is often hard to see and consists of many tiny dots scattered all over the white area of the print. This is caused by residual charge that can't be neutralized during the erasing step. An old drum may also develop fine rotational lines from the drum cleaning blade. These lines appear as thin black lines on the prints.
An old charge corona wire can cause wavy black streaks (and rainbow streaks on a color printer).
IMHO when there is a lack of toner, the customer will usually call in with a problem of extremely light prints. This is because the lack of toner usually is not absolute, but yes lack of toner in the development unit can cause almost blank prints.
Very light copies can also be caused by a failure of the transfer corona wire (or roller, or belt).
Improper cleaning can cause dirty copies or streaks. This can be caused by a worn out drum cleaning brush or drum cleaning blade.
Ghosting can be caused by failure of the erase lamp(s) or by bad drum ground.
If the laser fails you can get blank prints because nothing is written, therefore there is no latent image to develop. In the real world the machine usually throws an error code and stops itself.
If there is a film of toner dusting the thin strip of glass that the laser beam passes through to write the drum, then you can get void (white) lines where the toner blocks the laser.
A damaged hot roller of the fusing unit can cause black lines from rotational wear to the roller. Usually these lines are not as crisp of a line as seen from a worn drum.
An old hot roller can also cause image ghosting from toner sticking to the hot roller from a printed sheet, then this same toner getting laid down on the next sheet (making a fainter ghost image of the previous sheet's image).
Uneven pressure from a worn pressure roller of the fusing unit can cause smearing or blurry image, chunks missing from the pressure roller can cause unfused parts of the image (loose toner). This is because the toner needs heat and pressure to properly fuse. It also needs the correct amount of heat and pressure.
Any roller or part that transports the paper through the machine can cause a paper jam.
Gradual failure of door safety switches can cause intermittant problems with the laser or jamming.
Remember that many laser printers use a photoconductor unit or imaging unit that is meant to be replaced at a certain interval and usually contains all of the drum, drum cleaning, and development parts. The fusing unit will be separate, as will the transfer / paper separation assembly. Some machines employ a separate development unit, while others break it down even further and require a qualified technician to replace the individual parts such as the drum, developer chemical (powder consisting of a mixture of toner and carrier), drum cleaning blade, filters, etc.
Just remember for the A+ test that if you get a question about poor print quality, the first thing to try is replacing the maintenance kit. It may be called a imaging unit, or a electrophotographic unit, a PCU, a drum unit, or an all-in-one unit.
Also, as previously mentioned, the A+ seems to like the question about what happens when the drum does not get charged (conditioned). Black copies, and I mean totally black copies from edge to edge!
Actually, the maintenance kit has nothing to do with the toner cartridge, where the drum is located. The maintenance kit consists of a fuser or fusing element and rollers and in some models, separation pad(s).
Bad fusers can cause plenty of paper problems, like smearing, paper jams.
Strangely enough, on practice exams, I've only ever seen printer questions related to what goes on inside the toner cartridge. There are so many intriguing mysteries involved in printer troubleshooting that have nothing to do with print quality, like scanner issues, LVPS(low voltage power supply) issues, paper feed issues, etc. Should we expect to see questions relating to any of these?
A virtual pint to anyone who can correctly answer this one:
You give the command to print to your laser printer, and suddenly it emits a loud, continuous sound not unlike a jet engine taking off. What's the first component you suspect?
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