Laser printer smearing toner across the whole page...

[eccerr0r]

I have a HP Laserjet 5P. It's smearing toner across the whole page - while the page is printed, it's a shade of gray all along the whole page. There are clear banding parallel to the paper travel, so it's not a roller issue.

I'm guessing it's one of the scrapers inside the toner cartridge.

Anyone had experience with this and know how to fix this?

I had this happen to an old cartridge. When I replaced the cartridge, at first it was working nicely but after a few hundred pages it's smearing once more... A NOS cartridge so perhaps age had something to do with it, but I'm not sure if I want to risk getting another cartridge to experiment...

[stj]

Re: Laser printer smearing toner across the whole page...

start by taking out the cartridge and cleaning the rubber transfer roller.
then use a tissue to clean the drum.

[eccerr0r]

Re: Laser printer smearing toner across the whole page...

There's a rubber roller in the printer (I forget what its name is, might be charge transfer roller) that I can wipe. Usually that first time after I wipe it off, the first print is better than usual, but after that page it quickly returns to the steady state.

The photodrum constantly gets dusted with toner.

[stj]

Re: Laser printer smearing toner across the whole page...

the transfer roller is conductive, if it gets grease on it then it wont transfer the toner to the paper properly.

[eccerr0r]

Re: Laser printer smearing toner across the whole page...

I've actually got two LJ5P's that have the same problem now, which is kind of strange.

The whole page gets smeared, almost fairly evenly. I'd imagine if the transfer roller has grease spots on it, it'd splotch every so often in a repeated pattern as it rolls down the page?

[stj]

Re: Laser printer smearing toner across the whole page...

true.

a quick functional description may help.

the laser draws onto the drum,
the toner should only stick to the areas hit by the laser.
then the drum transfers the toner to the paper.
finally the paper goes through the fuser and the toner sticks.

now the reason the toner clings to the drum, and jumps to the paper is static electricity.

so maybe there is a bad HV board or poor connection to the drum in the toner cartridge or to the transfer roller.

btw, what is a 5p?
is that the cutdown 5 or the faster 5?
i always get the p,plus and + all mixed up!
i have a 5m myself.

[eccerr0r]

Re: Laser printer smearing toner across the whole page...

5P is the cut down 5, smaller "personal" version but still 600DPI. (5si is the big fast one, and the "M"'s are postscript for ... Macintosh. At least it's not the L which is the really slow "lite" one.)

Hmm... will have to look at the HV then. Main gist is that I don't think it's clearing the excess toner from the drum as it's coated with toner powder after using it instead of being clean...

I was thinking the toner cartridge wasn't scraping off the excess, and it was weird that it was working for a bit when I first put in a new cartridge... Now to locate how the HV gets connected too...

BTW how high voltage is high voltage? Looks like the PSU board will be a pain to access... hmm.

[stj]

Re: Laser printer smearing toner across the whole page...

several KV atleast afaik.
it's transfered into the toner cart with sprung pins.

[eccerr0r]

Re: Laser printer smearing toner across the whole page...

Aha! I see two sprung pins, now to somehow tap off of them so I can measure the voltage...
with a meter that can read thousands of volts and not my crappy DMMs...

[stj]

Re: Laser printer smearing toner across the whole page...

there is a HP5 service manual around.

[eccerr0r]

Re: Laser printer smearing toner across the whole page...

yeah, it looks kind of involved to disassemble it... sigh.
Looks like the HVPS is directly under the contacts, which means there's no wire to tap to see if the hvps is working...

[eccerr0r]

Re: Laser printer smearing toner across the whole page...

Ok I think I might have ruled out the HVPS.

1. Black taped back contact.... get dirty white page.
2. Black taped inside contact... get virtually all black page
3. Black taped drum contact... get weak printout
4. Removed all black tape... get original gray background with some print replication smearing.

Maybe fuser is dirty and bad? No, ruled out fuser - because drum is contaminated with toner.

Hmm...really need to find what diameters are of each roller... perhaps multiple problems here too?

(dangit, I need my printer to work to generate toner resist patterns to make PCBs!!!)

[stj]

Re: Laser printer smearing toner across the whole page...

not the fuser, that just bonds the toner to the paper.

i can give you some risky advice that works when i re-build hammered printers from the university.

take out the soft transfer roller - it's under the toner cartridge and is oposite the drum.
it unclips.

gently wash it with COLD water and dish washing fluid.
make sure it's fully rinsed off, and dry it with paper towels.
dont touch it after this without washing your hands first, or just lift it by the metal shaft-ends.

i find they get clogged with toner after 100,000-200,000 prints.

hmm.... pretty funny looking at that - anything other than a HP4/5 wouldnt be able to survive that long!

i find these really can last forever with a good clean.
the only failure i had was a bad rom on the postscript sim - so i binned it and set the printer type to a regular 5.

[jetadm123]

Re: Laser printer smearing toner across the whole page...

Since you have two LJP5's, is the "banding" different on the output of both printers? If yes, try exchanging the toner cartridges. If the banding follows, then I suspect the toner cartridge. I also think it might be the cartridge wiper blade, since letting it sit so long might have allowed the blade to stiffen up. Of course, if these are rebuilt or new non-HP cartridges, then all bets are off.

[eccerr0r]

Re: Laser printer smearing toner across the whole page...

My printer is relatively young in that respect, it's got just 10000 prints. Being a 5P I don't know if it was meant to take 100000 prints, but yes the older HP laserjets do last a while.

I noticed my print density is at setting 5 right now, but I'd imagine the print quality should be better than this even if this is too dark. I'll need to figure out how to set this back down to the default 3, I believe I set it to 5 before I hooked it up to the jetdirect, now I'm not exactly sure how to send raw PJL commands...

[eccerr0r]

Re: Laser printer smearing toner across the whole page...

I have three toner cartridges for the 5P and the 5MP, and all three of them streak darkness on both printers. The two "original" cartridges do this, and the new old stock cartridge also started doing this. Hard to tell the cartridges apart other than "darkness" of the actual print as I'm sure one of the cartridges is pretty much empty, yet it still seems to gray out the pages.

I was thinking the wiper blade in the toner cartridge too, but not sure if that can be replaced.

I was able to pull the transfer roller. I suspect I should either use compressed air (hmm. Maybe I should get an inline oil remover for my automotive air compressor) or vacuum it to see if I can get rid of the toner collected on it.

---

Attached is from the 5MP from two different cartridges. The one on the right is from the "newer" cartridge. The third cartridge is somewhat like the one on the right, the one on the left is the faintest of all the three but darkest background... The third cartridge has printing defects that I'm sure is caused by a scratched photodrum but also has the dark background.

The 5MP has it's darkness setting at "2". Both the 5P and the 5MP print very similarly depending on which cartridge is inserted but always has that gray background hue...

---

(and woah, this 5MP is just a baby. Not even 4 reams of paper has gone through it.)

[eccerr0r]

Re: Laser printer smearing toner across the whole page...

I think I sort of figured out why cleaning the roller helped, it was a false flag of sorts. I'm pretty sure it's one of the scrapers in the toner cartridge indeed. Cleaning off that roller worked because that roller was cleaning all the excess toner off that one of the scrapers in the cartridge wasn't doing, and was doing its job until it got full of toner, and then it would just splash toner everywhere.

I guess now it all makes sense.

I wish I could replace the scraper in the cartridge, or somehow fix it temporarily...

I just don't get why the scraper failed well before it ran out of toner... even for new old stock cartridges. I suspect for refills it would make sense.

Then the other question is how to prolong the life of these scrapers - cool? humidity? what else could make it last longer?

[stj]

Re: Laser printer smearing toner across the whole page...

3rd party clone cartridges are dirt-cheap on ebay.
and are fully filled - HP charge extra for that and put "XL" on the part number!

i think my last toner cost about $10 inc post.

[eccerr0r]

Re: Laser printer smearing toner across the whole page...

Well, that's the risk that jetadm123 hinted at - getting a "clone cartridge" may be simply refilled OEM cartridges, and who knows if they replace worn parts in the cartridge - and I'll get the same problem again down the line with a duff scraper, not to mention possibly scraped drums, etc. - seems like a craps shoot if you don't get completely sealed OEMs in bags.

The "NOS" toner cartridge I had was an official OEM cartridge. However the pull strip was not sufficient apparently as this "new" (but opened bag) HP toner still broke. This leads me to believe there's either some environmental issue or time issue, and there's nothing I can do about the time issue unless I guarantee fresh cartridges - and this royally sucks if it's yet another problem just like inkjet cartridges.

[stj]

Re: Laser printer smearing toner across the whole page...

probably a time issue, HP boxes have a use-by date on them!