SOT: Scanning old computer docs

[Kevin Parker]

If there is anyone on the list familiar with scanners I'd be most grateful
for some advice please.

Some time ago I bought a HP 8270 sheet feed (full duplex) scanner NOS. I
wanted to digitise a whole heap of old computer documentation and for a
little while I've been working through the big heap of stuff. But for quite
some time I've had an issue with scans that go through the sheet feeder
(irrespective of whether I do them double sided or not). Basically the
problem is that anything that goes via the sheet feeder has issues with
"streaks" in the document whereas anything done on the flat bed is perfect
(I have some links to some examples below).

By way of clarity, anything done on the flatbed the lamp traverses the flat
bed to do the scan. For sheet fed items the lamp is moved to specific slot
on the scanner and the sheet feeder takes over wrapping the document past
the lamp. Given that flat bed scans are OK I don't think its an issue with
the lamp.

I've done the following things to try to resolve the issue with no joy:

* Checked for any specific settings
* Tried doing scans in grayscale
* Tried increasing the resolution (default is 300dpi) to slow the speed that
the document is fed through the feeder.

According to HP the issue is a cleanliness one i.e. dirt on the glass can
cause reflections. I've followed their instructions for cleaning the glass
but still no joy.

Flatbed  example.

https://drive.google.com/file/d/1jYiFzERiZiaq7-WoTiQ2eIzITn6giviR/view?usp=s
haring

Sheet feed example.

https://drive.google.com/file/d/1WF4SHbwV3bVET_bzwIUiULywbCGZBf_V/view?usp=s
haring

Thank you!!!



Kevin Parker