HP Scanjet 3770 Scanner: Slow Operation

[Pete Nurse]

This message is driven more by bewilderment than anything else. I know
that scanners have a lot of work to do but I can't explain why my
scanner (and my previous one for that matter) is s-o-o-o slow.

The whole process of scanning a pair of negatives takes 200 seconds
(more on the first time through). It takes 60 seconds for the scanner
assembly to move out from it's hiding place. Then it takes a further 40
seconds (ie up to 100 seconds total) to actually start scanning - I
have left the lid open for 100 seconds and only then closed it - the
result is perfect. The rest of the time (100 seconds) seems to be
reasonably productively spent scanning (albeit slowly) with about 30%
processor usage.

So, the burning question is what is the scanner doing for the first 100
seconds? Is the whole process deliberately slowed down to prevent
overheating or something? Thanks for your help.

 

[Bart van der Wolf]

SNIP

So, the burning question is what is the scanner doing for
the first 100 seconds?

Most likely, it's warming up the lamp till it's a bit more stable in
output. That will help to get even brightness along the scan
direction. Then after warming up, it presumably calibrates itself, so
the sensor elements across the scan are equally sensitive and neutral
in color.

Then the actual scan requires a certain exposure time for each
scanline. As you have noticed, this takes enough time, given the
output of the lamp, to not swamp the interface and the scanner driver
with data.

Bart

 

[Pete Nurse]

Thanks for your response, Bart - it makes good sense.

I deleted my original post in the (mistaken) belief that it exposed my
private email address.

Here for anyone who missed it is that origanal post:-

This message is driven more by bewilderment than anything else. I know
that scanners have a lot of work to do but I can't explain why my
scanner (and my previous one for that matter) is s-o-o-o slow.