Canon 3200F - stuff under the glass - bad?

[Oliver Rothe]

Hi,

I just received a new Canoscan 3200F scanner and it has some stuff _under_
the glass, at the upper edge near the resting position of the scanning
line. It is not dust, it looks more like very fine spray residue
(about 1 to 2 pixels on a 1200dpi scan) distributed across an area of
a few cm^2.

What could that be? I did some test scans and it does not show up
in normal situations (I have to scan with the lid open and increase
the contrast by at least 5 times to see it), so I would
not go to the hassle of sending it back unless it indicates
a real problem.

Thanks,
Oliver

 

[Don]

Hi,

I just received a new Canoscan 3200F scanner and it has some stuff _under_
the glass, at the upper edge near the resting position of the scanning
line. It is not dust, it looks more like very fine spray residue
(about 1 to 2 pixels on a 1200dpi scan) distributed across an area of
a few cm^2.

What could that be? I did some test scans and it does not show up
in normal situations (I have to scan with the lid open and increase
the contrast by at least 5 times to see it), so I would
not go to the hassle of sending it back unless it indicates
a real problem.

I noticed the same thing on my scanner (Mustek BearPaw 4800TA Pro)
which prompted me to open it up and try to clean the underside with
lens cleaner liquid and paper. (I wrote about the whole thing a couple
of weeks ago, subject: "Care and feeding of flatbeds: Cleaning under
the glass".)

Since then the "fog" keeps coming back and I've already cleaned the
glass several times even using a microfiber cloth.

It appears to me that the "fog" seems to increase the longer the
scanner is on. It starts out pretty much invisible but then gets
stronger as the temperature within the scanner rises. This seems to
indicate either evaporation from the lamp or maybe some electronic
components which creates this condensation.

Anyway, I would also be interested to learn more about this even
though, as you say, the effect is very faint and the image needs to be
boosted radically to even notice it. Nevertheless, it's still there...

Don.

 

[Steve]

I wrote Canon recently about the same thing with my 5000F. I don't know that
I buy their reply, something along the lines of it was there to prevent
fogging or something and would not affect the scans. Didn't make sense to
me, but they're right in that I've yet to see any impact to my scans.

 

[lostinspace]

----- Original Message -----
From: "Steve" <>
Newsgroups: comp.periphs.scanners
Sent: Saturday, October 02, 2004 5:53 AM
Subject: Re: Canon 3200F - stuff under the glass - bad?

I wrote Canon recently about the same thing with my 5000F. I don't know
that I buy their reply, something along the lines of it was there to
prevent fogging or something and would not affect the scans. Didn't make
sense to me, but they're right in that I've yet to see any impact to my
scans.

I purchased a Canon D1250U in December of last year.
I recall reading either in the documentation or in a support web page of the
haze.

The entire underside of the glass was haze covered. More of a haze from
either smoke or the accumulation any scanner gets over time from plastic.
After one scan on this new scanner, I took it apart and cleaned both sides
of the glass thoroughly.
Perhaps it does and does not make a difference, however I do way too much
scanning and I'm not about to take any chance on possible quality loss of
such a trivial issue as keeping the glass clean.
I do notice a better quality of scan after the regular glass cleanings
which for me are every 4-6 weeks and in some instances sooner after a heavy
project.