M477fdw Color Laser Jet Pro - grey dots on left side for each printout

[Merigouldi]

All of the sudden little grey dots have started appearing for each printout.  They are about 1 1/16" from the left hand side of the paper and 1 1/16" apart.  I have attached a scan of one of my printouts (ignore the other stuff in the image, the glass is probably dirty) and you can see the dots clearly.  I do not think it is a cartridge issue since I have the problem even when I "print" a blank sheet from Microsoft Paint. 

Any help at all would be greatly appreciated.  Thanks a lot.

[Valsimot · Accepted solution]

It's the toner probably black it's damaged and it leaves dots even when not printing.

[Merigouldi]

Ok I guess I'll give the toner cartridge a change then.  If that is the problem then that would be fine since it's an easy fix.  I'll update soon.

[Repairatrooper]

Measure the dots carefully and compare the distance between dots to this chart.

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@Valsimot is probably correct that you have a black cartridge issue. You can check the cartridge to see if there is any debris like a bit of label stuck in the cartridge.

[Merigouldi]

I went out and bought a genuine HP black cartridge and it seems to have fixed the issue.  Thanks again for your help.