Toner darker down the middle of page - no lines

[joprinter]

Please help us solve this problem in my office!!! 

It doesn't happen on every print job but we are getting darker toner in the middle of the page - NOT lines, it's darker on the edges and the middle.  (a little hard to see in the pic, but the last few letter of "services" and half of "rendered" are darker, along with "Very" and "Jamie" towards the bottom.  Before you ask, please know that we have tried EVERYTHING we can think of.  This is only happening on 2 printers in the office that are on the same side as each other.  The buidling has tried replacing the electric wires, the data ports and we have tried everything from replacing the fusers to a complete maintenance kit and replacing the toner.  It does not happen on every print job, it can happen once and then not happen on the next print.  We need answers!!  our IT department is stumped!  please help!

[Dovid]

Hi JoPrinter,

I think that the good news is that it is not your print ports, your IT department, nor your Fusers or  kits.  Please let us know the age and the print count on the K cartridge in the engines that are affected.  While you expect lines as the end of life defect, we call (I believe) what you are seeing FADE.  The toner is probably very low and not uniformly distributed across the cartridge (and therefore the page).  Depending on the amount of toner needed to print each page, sometimes the toner loading on the system is decreased in areas and I believe what you are seeing is good toner at the dark areas and a bit lighter on the other areas.  Your whole print should stand out with the darker printing.  One way you might tell is to take out the cartridge and shake it side to side 5-10 times and put it in without tilting one way or the other.  That should make the next several (10-20) prints dark everywhere.  If things are still light or varying across the page and you have other printers of the same model in your area, swap the cartridges in the two machines and see if the problem travels with the cartridge.  Then you will know that a new one is needed, which is what I strongly suspect.  Don't worry if the machines indicate "Non-HP" in a different printer - that would also indicate that the cartridge has passed the internal low indication and may be out of warranty.  Please keep the lines of communication open.  Dovid

[joprinter]

I forgot to mention that it is not the toner, either.  That was the first thing we tried.  We replaced the toners and even tried using a HP brand toner and not the knockoff as we usually do.  I just replaced this toner a few weeks ago.  How do I go about getting a K Cartridge count? 

[Dovid]

JoPrinter,

Not that HP could say this,  but as a private citizen, when we test non-HP knock-off brands in our machines to see what happens, we often get so much dirt and dust inside the machine (toner leaks, etc.) that the machine needs a complete cleaning and vacuuming before we can get good printing out of it.  We have special vacuums, since toner dust goes right thru the bag of a normal vac.  That is why HP strongly suggests only using HP original toners.  That being said, you might be able to clean the laser path and enough of the components inside the machine to bring the system back to life if stray toner is the culprit.  I suspect that the difference in darkness, if it stays in the same locations print to print, could be such stray dust on the glass cover of the laser path.  Since I don't have info on that machine with me, the laser path can be found by looking at the cartridge and finding a clear path that one can see the green roller, but not the part of the green roller that sticks out of the cartridge but the "other side" that is inside the cartridge, usually between two halves of the cartridge.  The laser shines from the inside of the engine into that path.  that is where I would start looking.  Dovid

[Dovid]

Just as a quick add, HP has seen some of this local reduction of laser power if the machine has been kept in a very dusty environment, no matter what cartridges are used.  Machines in tool shops, wood shops with "sawdust" in the air, etc. can sometimes contaminate the same laser path I described before.  Sometimes cleaning helps this, but sometimes this gets into the actual laser scanner and contaminates the mirrors inside.  Not something that many folk would be capable/willing to tackle as a fix.  Please let us know what you find.  Dovid

[joprinter]

i checked the toner and am not able to access the inside - I can see it - and the green roller looks clean as can be.  I understand that using the non-HP toners is not ideal, but that is what our company wants.  We have had complete service and cleaning of the printers, but I don't know if our service guy has the special vacumm you speak of.  We are puzzled by the fact that this is only happening on 2 of our 5 printers in the office - with the two trouble printers being on the same side of the building.  All of the printers are the same age and all use the Non-HP toners.  That is what prompted the electrical supply investigation and subsequent new electric wiring and data ports.

[joprinter]

If this is the case, I would think it would print like this all the time and not just some of the time.  Is it possible that it could be a problem with Word?  Seems to do it more when printing from Word.

[joprinter]

never mind my word comment - just when I think I can narrow it down, it surprises me.  I've attached our printed conversation

[Dovid]

Sorry I may not have been clear.  Looking at the cartridge was only to FIND the laser path.  The laser and the glass to clean (or to have your service person clean) is in the machine but has to shine down into the cartridge while it is in the correct position in the machine down that slot that you found.  The page to page and time to time variation can have many answers and causes.  Basically YES - even if dirty, depending on the image, the areas that block the laser are most of the time may not show up.  Thus, on a page with 2 or 3% coverage like office documents, the spots on the page that might be dirty or dusty would be down the page in dirty and dusty areas in bands of lightness.  Often they might not be seen unless the cartridge is low on toner, since calibration often compensates.  Dovid

[Dovid]

I still think it is a printer problem, not word or electrical wiring, etc.  Wow, by the way, it is worse than I have seen in many, many years of laser printing work.  I still think it is a dirty laser path.  However, is it possible that those two machines are in direct sunlight near a window?  there is a science thing that happens with that green drum.  If it has lots of light on it for a long time, it can fatigue and cause different printing on the area that is exposed.  It can be exposed thru the machine covers and even deep in the machine if the light hits the machine the "wrong" way.  That would be interesting as a cause.  Dovid