Black Line only when *scanning* from ADF, not copying

[lamikie]

Hello, I'm having a problem that has me stumped.

I'm getting a classic thin black line down my pages when scanning from my HP7740 ADF. 

But, to clarify - it is ONLY when scanning and ONLY from ADF.

Copying from ADF - no problem.

Scanning from flatbed - no problem

Copying from flatbed - no problem

It seems bizarre to me that it would only be from scanning on ADF but not also copying from ADF...aren't they using the same sensor?

I know this can be a common problem with debris and such so I have cleaned and checked all areas of the glass scanning sensors are, carefully. Including air blowing for debris, on both the bed and the lid.

My firmware is up to date

I have unplugged the printer and waited 60 seconds and plugged it back in.

Any thoughts on how this could only be on ADF scans ONLY but not copies from ADF?

Thank you!

[Andr-1611]

Hello @lamikie 

Everything you wrote sounds plausible.

But:
1. A scan from the ADF has a standard resolution of 300 dpi.
2. A copy from the ADF has a resolution of ?

That's why you should check the small glass surface again very carefully.

It is advisable to use a magnifying glass, as very small smudges cannot be seen with the naked eye.

Kind Regards
Andr-1611

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