asked Jun 2, 2004 at 12:53pm
Hp HP Color LaserJet 4550

HP 4550 vertical Faded Streaks

Hope this post is helpful to those who come across this baffling problem. I was asked to look at a color Laserjet 4550 that had two one inch wide vertical lines from top to bottom of the page on the right hand side. The printed image in the lines was visible but very faded except for black it looked a little faded. My first inclination was the transfer roller but the printer had just been serviced and a new transfer kit was installed the day before as well as a new drum unit and ITB. I re-checked all of the new parts in another lj 4550 and they were indeed all good parts. I noticed that the printer had been cleaned when the new parts were installed so the usual toner dust was not everywhere. I completed several tests including the formatter line test and discovered that the color lines were faded or missing on the same areas and the black lines were printing a little light. I remover the cover and opened the scanner. The scanner was full of cyan dust. I cleaned the outer scanner lenses with a small paint brush and that fixed the problem. I guess the people who cleaned the printer used canned air or a compressor and that caused the optics in the scanner to get fouled.
Beware of canned air!
I had a HP 4550 shipped to me via UPS. The toner cartridges were packed on the outside of the printer and subsequently squashed. The styrofoam rubbed against the plastic housing of the printer for hours creating a huge static charge. The toner, now contained within the box and being shaken around went into every nook-and-cranny... everywhere.

I found toner covering the bottom of the prism and even toner inside of the laser unit dusting the optics. Carefully cleaning these surfaces (vacuum + careful use of compressed air + a paint brush as above) fixed my fading and streaking problems.
by Dirkasaurus-rex on Nov 17, 2005 at 4:52pm Add comment
I'll bet they forgot to clean the waste tray inside the printer. This is why I won't ship any big printers.
by moe on Nov 17, 2005 at 5:00pm Add comment
Waste tray? There isn't anything by that name (or similar name) in a 4550. Which item are you referring to?

Yes, shipping big printers... bad idea.
by BYUI_PaulL on Nov 18, 2005 at 11:43am Add comment
The tray Moe is referring to is located above the fuser. You have to remove the fuser and in the middle you will see a black tab which is part of the black tray. You just grab the top part of the tab and pull the tray out.
by dmzcompute on Nov 18, 2005 at 12:08pm Add comment
Ah! Thanks!
by BYUI_PaulL on Nov 18, 2005 at 9:08pm Add comment
You guys just made me very happy. We were tearing hair out over this. Now we have clean lens and clean prints!
by unknown on Sep 28, 2006 at 7:16am Add comment
I'm having the same problem in my 4550 as Mike in the first post. I've replaced everything but the transfer kit, and I'm still getting these light streaks across the page.

"I completed several tests including the formatter line test and discovered that the color lines were faded or missing on the same areas and the black lines were printing a little light. I remover the cover and opened the scanner. The scanner was full of cyan dust. I cleaned the outer scanner lenses with a small paint brush and that fixed the problem."

How do I perform the formatter line test? And how do I get to the scanner in order to clean the lens?

Thanks for your help,

by bodyalive on Oct 24, 2006 at 3:28pm Add comment
You have to take off the top cover to get to the scanner.

The engine test will just show you the same problem as the other test pages.

The dust is not really cyan, it's a mixture of cyan and the other colors that has a purplish hue.
by Stephen on Oct 24, 2006 at 4:11pm Add comment
OK, I've checked out the scanner. It did not need cleaning.

Here's what I've got... a HP 4550 with a new fuser and drum. Transfer belt shows 88\% remaining.

I've printed out a test page that has wide bands of black, cyan, magenta and yellow printed across the width of the page. Instead of solid color bands, many very faint vertical lines from top to bottom are appearing in each color. I put in a different drum and the lines still appear in the exact place on the page.

Any ideas?
Thanks, Brian
by bodyalive on Oct 25, 2006 at 10:52am Add comment
Im having a sightly differnt problem.
I have a 4550n and over a day it prints fine right up till about 5.00pm then it fades out until no blank txt can be seen.
We then go home come in the next day and everything is find.
We have replaced all then usally stuff and there is plenty of ware on everything.
Any idea's
by unknown on Jan 28, 2008 at 8:05am Add comment
If you have vertical streaks, that fade the colour of whatever is beneath them, then it could be the laser/scanner at the top. If the streaking is not on all of the colours, sometimes goes away or appears in different places then IT is probably NOT the laser/scanner assembly.

the laser assembly is hard to get to - I have just done it and it was a bit scary.

Make sure the printer is off, disconnected and has had 30 mins or so to cool down.

First you have to get the whole plastic top off the printer. the top has two screws at the back, and clips round the front. I had to remove the drum kit (don't expose to sunlight) and one of the sides too before i worked it out.

Now you will see a large metal surface with about 10 screws in it - get them all out and put the metal cover to one side.

Inside you will see a plate with a yellow warning sticker on it. This is the one you need to get off. it has about 6 black screws. remove the screws, and remove the black wire holder on the right. some of the wires are connected to the laser unit, through the top of the plate with the yellow sticker on it. carefully ease this connection out.

BE CAREFUL - do not get dust inside the laser housing.

using dry q-tips brush all the optical surfaces. It may not be obvious which one has dust on it. now put it all back together again.

hold your breath and see if it worked!

by unknown on Mar 13, 2008 at 3:24am Add comment
Incredible! My printer hasn't printed this great in years! The reds are red again, etc... It is like I have a brand new printer and the only thing I did is clean the lenses as you recommended. I just can't believe it was something that simple. Thanks for the post and taking the time to post! Saved me alot of money and alot of down time!
by unknown on Dec 2, 2008 at 10:56am Add comment

I just bought a used HP4550 printer and I have faded streaks on the printed page. Here is what I have;

Cartridge information;
Black toner 100\%
Cyan 100\%
Magenta 100\%
Hellow 100\%

HP Drum Kit 84\%
HP Transter kit 77\%
HP Fuser kit 85\%

Total printed pages 7669
in color 6875
B/W 794

What would my first step be in getting the steaks to go away? If I open the door #1 there is alot of dust in this area. Any help would be appreciated.
by klpost on Dec 29, 2009 at 11:31am Add comment
Probably got moved with the waste toner tray full of toner. If you open the rear door and disconnect the latches holding it, you will be able to flip the blue latches on the fuser and pull it out. The waste tray sits behind and above it and slides out.
Since there is that much dust, we'll theorize that it got up inside the laser scanner unit and is on the mirrors diffusing the laser beam in those areas where there is fading. You'll have to take the top off to access the laser scanner, open it up and clean the mirrors with a dry cotton swab. Help yourself to a free manual
by moe on Dec 29, 2009 at 12:45pm Add comment