HP Laserjet producing speckling

[JBR]

HP Colour Laserjet M252dw

We have tilted backwards this printer in order to remove a jammed sheet of paper from underneath, which we managed without any problems. However, the next time we printed a letter in black, the sheet featured blue speckling all the way down one side of the front of the sheet.
Printing documents entirely in another colour, for example dark blue, produces acceptable results which will do for now, but attempting to print in black comes out with the blue speckling.
The printer is no longer under warranty.

We could, of course, buy another black cartridge in the hope that this may solve the problem, but as we all know they are expensive things!

Can anyone offer any suggestions to help sort out this problem, please.

 

[opps]

Isopropyl alcohol on a cotton bud might help to clean the print the head- no guarantees though. At a push, try a cotton bud and warm water.

 

[JBR]

Isopropyl alcohol on a cotton bud might help to clean the print the head- no guarantees though. At a push, try a cotton bud and warm water.

Thanks. You feel that the problem lies with the black print roller then. That makes sense, as the other three colour ones print properly.
We have wiped the black cartridge roller very gently with a tissue, so could try some alcohol. The problem is trying to do that to the whole surface of the roller, as I cannot turn it round by hand and don't want to touch the surface with my fingers.

 

[mcprinter]

Ex Printer Tech here

I think Opps thinks this is an Inkjet Printer. Don't use Alcohol on it.

As you have moved it, some waste Toner has probably got somewhere it shouldn't.
Will probably disappear after a few pages - Always used to run 10 or more Pages with just a Full Stop on to pick up any stray Toner.

Newer Machines have a 'Cleaning Page', including yours.

See Step 1 and select the type of Display you have (Buttons or Touchscreen)
https://support.hp.com/gb-en/document/c04518481

 

[JBR]

Thanks for jumping in, Mcprinter.
No, I haven't used any alcohol on it, though as I said earlier, I carefully wiped the black cartridge roller with a soft tissue.
I'll try the cleaning tip (full stop only) first, as the cleaning page if I remember prints a page full of text. It will be interesting to see what a single full stop (in black) produces.

I'll also read through the link you provided. Thanks.

 

[opps]

Ex Printer Tech here

I think Opps thinks this is an Inkjet Printer. Don't use Alcohol on it.

As you have moved it, some waste Toner has probably got somewhere it shouldn't.
Will probably disappear after a few pages - Always used to run 10 or more Pages with just a Full Stop on to pick up any stray Toner.

Newer Machines have a 'Cleaning Page', including yours.

See Step 1 and select the type of Display you have (Buttons or Touchscreen)
https://support.hp.com/gb-en/document/c04518481

Yup, my bad, I misread the OG's first post and assumed that it was an inkjet.

If I had read it properly, I would have recommended the cleaning sheet/page

https://nerdtechy.com/best-laser-printer-cleaning-sheets

 

[JBR]

I apologise for not responding yesterday, as I was in the hospital for a large part of the day and couldn't find time to follow these suggestions.

I have now printed off ten sheets, each containing only a single black full stop. Unfortunately, the speckling (which is definitely blue) is exactly the same on all ten. I also did the same with a mid-blue full stop and out came a clear sheet of paper.

There is something strange here.
Going by the fact that other colours print correctly, would you suggest that I buy a new black cartridge and hope for the best, or are there any other ideas I could try?
Thanks again for all your help.

 

[mcprinter]

Try the Cleaning Page from the Menu.
If no joy, can you post a Pic of the full page?

 

[JBR]

Try the Cleaning Page from the Menu.
If no joy, can you post a Pic of the full page?

Thank you for this. I have run the cleaning page from the menu on the printer's screen and have attached an image. I realise the speckles are very small so you might need to zoom in to see them!

 

[mcprinter]

For a Toner fault, you would expect to see a repeating defect.
i.e. a 1 Inch Dia Roller would leave a mark every 3.14 Inches (Pi x D)

Looks like some stray Toner from the Cyan.
Might be sat on the Intermediate Transfer Belt (Shiny Sheet that is under the Toners when you push them into the Printer).

Troubleshooting Manual here
Have a Search for Repetitive Defect and Paper Path
https://www.laserpros.com/img/manuals/hp-manuals/hp-clj-m252-m274-m277-troubleshooting-manual.pdf

 

[JBR]

Looks like some stray Toner from the Cyan.
Might be sat on the Intermediate Transfer Belt (Shiny Sheet that is under the Toners when you push them into the Printer).

Troubleshooting Manual here
Have a Search for Repetitive Defect and Paper Path
https://www.laserpros.com/img/manuals/hp-manuals/hp-clj-m252-m274-m277-troubleshooting-manual.pdf

Thank you.

A search for 'paper path' was quite enlightening but at the same time a little worrying as the last mention under 'cleaning page' states that 'this function removes dust and toner from the print paper path' and, of course, my cleaning of the printer didn't remove the speckling.

The 'intermediate transfer belt' that you mention could indeed have some stray toner from the cyan drum, though why this only prints when we print in black I can't understand. Nevertheless, I suppose I could remove all four toner cartridges and have a look underneath.
If I do, and see some stray toner, can you suggest the best way I should go about clearing the toner or perhaps would you advise me to have this done professionally?
I'm not sure how much this would cost, though, and also if there is anyone locally as sending the printer elsewhere might be difficult.

 

[Nozzle]

Try cleaning off the corona wire. It usually has a scraper which you run back and forth. (The corona wire discharges the charged particles so they can drop into the waste)

Nozzle

 

[JBR]

Try cleaning off the corona wire. It usually has a scraper which you run back and forth. (The corona wire discharges the charged particles so they can drop into the waste)
Nozzle

Is this the 'drum cleaning blade' which I have seen on the diagrams? If so, isn't that inside the toner cartridges?

 

[Nozzle]

On my Brother the corona wire is beneath each toner roller, and separate to the toner.

Nozzle

 

[mcprinter]

On my Brother the corona wire is beneath each toner roller, and separate to the toner.

Nozzle

How old is your Brother? Rare that Coronas are used these Days.
Use very high Voltage 7KV to pull the Toner Image from the Drum onto the Paper.
Creates Ozone (burnt O2 I think). Smells a little like Bleach.
Back in the Day, sniffing the HV Power Supply was a 'good' way of diagnosing a dead one

Most Printers use a Transfer Roller to pull the Toner to the Paper.
This HP has 4 Transfer Rollers in the Belt to get each Colour onto the Belt and then another one to transfer from Belt to Paper.

Are you still awake?