Blue, red and yellow streaks/shades on scans (TaskAlfa 250ci)

[alkatasz]

Hi everyone,

I have a TaskAlfa 250ci that shows strange streaks on scans, that almost look like an overexposure of sorts. I tried to search if someone has had a similar problem but I couldn't find an existing thread.
I've attached an image of the scan so you can see the problem. I scanned the page with the long side on the left edge.

[blackcat4866]

Re: Blue, red and yellow streaks/shades on scans (TaskAlfa 250ci)

Your scanner is out of focus. Very few modern manuals go into the details of properly focusing the scanner. The reason that the images varies in hue is that the RGB lines of the CCD are misaligned with the image. Here are my suggestions:

There are two basic CCD adjustments
1) moving the CCD left - right.
2) raising or lowering the front or rear of the CCD. These screws are painted, which indicated factory adjustment only. Even so ... you'll probably have to adjust them.

It's probably the CCD height that is mis-adjusted. If the front of the image has the anomaly you must adjust the rear of the CCD (or vice-versa). Make an mark on the adjustment screw and take care to count rotations as you adjust. Decide to raise or lower the one side of the CCD by two full rotations. If the anomaly gets worse return to the original position then continue two rotations in the other direction. Continue in this way with gradually diminishing numbers of rotations. Your last adjustment will be 1/8 of a rotation.

You'll learn as you go.

This is an example of a bizhub 423 scanner with a similar issue. It's a monochrome scanner so you don't see the variations in color. These are ANSI B prints (11" x 17") so they scan and print SEF. Focus issues are best seen at the trail edge of ANSI B/A3.

bizhub 423 focus.jpg

Do you have questions? =^..^=

[alkatasz]

Re: Blue, red and yellow streaks/shades on scans (TaskAlfa 250ci)

Thanks for the quick reply!

If I understand correctly, I will have to adjust the CCD using the screws with the orange resin in the picture is that correct? I checked the service manuals but as you said this topic wasn't mentioned in it.

[blackcat4866]

Re: Blue, red and yellow streaks/shades on scans (TaskAlfa 250ci)

These are your height adjustments:

photo_2020-01-26_19-14-46.jpg

=^..^=

[alkatasz]

Re: Blue, red and yellow streaks/shades on scans (TaskAlfa 250ci)

Thanks for the info, I'll post a heads up with the results.

[tsbservice]

Re: Blue, red and yellow streaks/shades on scans (TaskAlfa 250ci)

Those "cool" streaks pattern is almost what every CCD out of alignment shows.
Expect lots of trials and tribulations, plan your adjustment steps well.
Good luck

[Santander]

Re: Blue, red and yellow streaks/shades on scans (TaskAlfa 250ci)

One thing I would check before adjusting the CCD. On the bottom of the mirror frame assembly are two small white sliders, one on each side. Had a 250ci two months ago where after 800K plus scans [copy and scan to folder] it had worn out and fallen off the mirror frame throwing the focus off. Mine was on front side of the frame assembly as yours appears to be, simply replacing the slider did the trick for me.

[copiertec]

Re: Blue, red and yellow streaks/shades on scans (TaskAlfa 250ci)

Before adjusting the ccd, i would make sure your mirrors are in place and aligned, first. We had a Kyocera machine that was moved by a third party vendor and they knocked the bottom mirror out of place causing a similar problem with scanned images.

[alkatasz]

Re: Blue, red and yellow streaks/shades on scans (TaskAlfa 250ci)

Thanks for everyone's help, I fixed the issue today. I've attached an A3 scan from after the repair
screenshot.239.jpg

In the end I marked the position of all the screws and tried the ones blackcat4866 suggested but they didn't have any effect. Then I moved to the one in front of the CCD et voila, it worked. After 5 minutes of turning the screw ever so slightly, the shade moved downwards until it was completely gone.
Again, thanks for the help everyone!

photo_2020-01-26_19-14-46.jpg

[FrohnB]

Re: Blue, red and yellow streaks/shades on scans (TaskAlfa 250ci)

Thanks for everyone's help, I fixed the issue today. I've attached an A3 scan from after the repair
[ATTACH=CONFIG]44743[/ATTACH]

In the end I marked the position of all the screws and tried the ones blackcat4866 suggested but they didn't have any effect. Then I moved to the one in front of the CCD et voila, it worked. After 5 minutes of turning the screw ever so slightly, the shade moved downwards until it was completely gone.
Again, thanks for the help everyone!

[ATTACH=CONFIG]44744[/ATTACH]

Thanks for getting back to us and posting the FIX!!

[blackcat4866]

Re: Blue, red and yellow streaks/shades on scans (TaskAlfa 250ci)

Congratulations on your success! =^..^=