[Misc] Canoscan Lide 700f calibration

[AlanHK]

Hope this is kosher here, the Canoscan is just a flatbed scanner, no printer. But presumably shares tech with MFPs.

I have a Canoscan Lide 700f, probably over 10 years old, the manual is dated 2009.

I use it a few times a year to scan photos usually, for DTP. So I need good scans.

Last year I noticed banding, like pinstripes, in the scans. After a search I found this article:
How to calibrate your Canoscan Scanner in six frustrating steps - Fully Psyched
which documents the problem and gave a solution; which is to do a "platen calibration".
That did work, but I used the scanner again recently and the problem had returned. Again, the calibration cleared it.

So I am wondering what the cause is, and what "calibration" actually means and if it is going to eventually get unfixable.

I guess calibration means focusing the scanner so it exactly focuses on the paper surface on the platen.
Don't know though if this is a software or hardware correction.

Could it be that the scanner gets out of place when I store the scanner? I have been putting it in the box between uses, then stood it on its side.
So now I will store it horizontally, and also I will engage the lock which I have not routinely done.
If I do that, would it remain calibrated, or is this a precursor to it going out of whack regardless?

Of course I have started to look out for a replacement, but cash is tight.

Image: scan with stripes.

badscan.jpg





.

[onlyinnewfoundland]

Re: Canoscan Lide 700f calibration

Probably just due to age and storage for long periods, the bushing under the CIS unit is probably getting sticky or having a bit of a shake when it initially goes across the rail for the first while after being stored for a while.

Calibration probably going to be necessary going forward.

Storing it flat instead of on it's side might help, only time will tell.

[Canuck]

Re: Canoscan Lide 700f calibration

Usually Canon scanner calibrations set white reference levels, like for shading correction on copiers. It probably needs to have the CIS unit cleaned, clean any white reference strips on underside of glass,etc. Cleaning is a start

[AlanHK]

Re: Canoscan Lide 700f calibration

Usually Canon scanner calibrations set white reference levels, like for shading correction on copiers. It probably needs to have the CIS unit cleaned, clean any white reference strips on underside of glass,etc. Cleaning is a start

"underside of glass"
The last time I tried to open up a scanner to clean the gunk off the glass, I cracked the glass trying to pry it out. These are not made to be user-serviceable.
There's nothing in any manual I could find about that for sure.

Anyway, it doesn't look obviously dirty inside, and dirt would not cause the regular stripe pattern I see before I calibrate it.

[Canuck]

Re: Canoscan Lide 700f calibration

Yes probably not designed to be serviced I agree. But I've been working on Canon scanners and printers/mfp/digital presses for over 30 years. I know tons of techs that would tear into it and clean it,reseat cables, etc.lol. This is a tech forum, I give tech suggestions. Good luck

[AlanHK]

Re: Canoscan Lide 700f calibration

Yes probably not designed to be serviced I agree. But I've been working on Canon scanners and printers/mfp/digital presses for over 30 years. I know tons of techs that would tear into it and clean it,reseat cables, etc.lol. This is a tech forum, I give tech suggestions. Good luck

Well, to me, the regular stripes do not suggest a problem with dirt.

If you have a link to where I can find how to tear it down I would really appreciate that.
There are no visible screws, so if it comes apart at all without destroying it, it will be concealed clips.
I have done work on various laser printers, which do have take apart instructions, to clean and swap parts.
But trial and error attempts to disassemble these scanners, not knowing what needs to be forced and pried to release, and what will break, has not been a happy experience.
The more high end devices you mention are designed to be fixable.

[Canuck]

Re: Canoscan Lide 700f calibration

I work on small cheque scanners and many things that aren't designed to come apart. Do you what shading correction is? What happens when scanners are dirty and fail shading correction?You seem to know everything, so our conversation is done.

[AlanHK]

Re: Canoscan Lide 700f calibration

I work on small cheque scanners and many things that aren't designed to come apart. Do you what shading correction is? What happens when scanners are dirty and fail shading correction?You seem to know everything, so our conversation is done.

If I knew everything, I would not be here asking questions.
I don't know how to open this scanner, for instance.
And no, I didn't know what shading correction is, looked it up and it might be relevant, but I don't understand how the dirt specks that corrects for would cause regularly spaced stripes.
The article I linked and the replies to it show this is a problem with this model, the consistency of the stripes suggests it's not dirt.
I've seen scans with irregular lines from dust. Had those on an old fax machine till I worked out how to clean the mirror.
I'm not a professional technician, just trying to maintain the machines I use.