Re: [gentoo-user] Scanner and weird streaking

[Dale]

Michael wrote:
> On Friday, 30 December 2022 02:28:32 GMT Dale wrote:
>> Howdy all,
>>
>> I have a HP scanjet 4570c flatbed scanner.  I bought it used years ago
>> and most of the time, it works just fine.  On occasion tho, I get
>> something weird.  When I scan something, it adds some pinkish colored
>> streaks.  I took a scrap sheet of paper and scanned the back of it. I
>> used a magic marker on some text that was there, also drew a smiley face
>> on it as well.  Anyway, the side with print is on the opposite side.
>> Basically, it is also seeing the back side of the paper.  I'm not sure
>> if that could cause this weird streaking but wanted to mention it.
> I've come across the pink hue artefact on an old HP scanner, but can't recall
> the model.  It is not related to the print of the opposite side becoming
> visible, which is caused by a high light exposure setting.  You need to reduce
> the exposure to a level where you can see the primary print clear enough,
> without the back side bleeding through.
>

I kinda figure that.  It is pretty bright.  I don't recall seeing a
setting for it but I may not have seen it.  I mostly tried different
color settings, resolution and such.  Goes to show tho, it is
sensitive.  ;-) 


>> At first, I thought it was something on the glass so I disassembled the
>> thing and cleaned it as best as I could.  When I put it back together, I
>> concentrated on the back side of the glass, since I have to disassemble
>> it to clean it.  I also clean the side the document goes on regularly.
>> If it changed, I can't tell it.  Another odd thing, the streaks change
>> depending on the document.  Sometimes you can barely see it, other times
>> it is awful.  I've not been able to reason out what makes the difference
>> tho.
> Cleaning the glass won't affect the pink hue.  I dismantled the scanner and
> cleaned the glass too, with no improvement.
>
>
>> I've got about the same results using Scanlite, Scanpage and XSane
>> software.  XSane may be a tiny bit better but it does vary at times.
>> There's not a lot of settings available.  I tend to use either 100dpi or
>> 300 dpi for resolution thingy. I fiddled around a bit but it doesn't
>> seem to help.  This is a link to the page I described above.  It's a
>> little sizey so I didn't want to attach, for those who have email
>> clients that puke a lot.  lol
>>
>> https://freeimage.host/i/HTQLpWb
>>
>> You may notice that it is a little heavier at the top and gets lighter
>> as it goes down.  I've checked the glass, I can't find anything that
>> would cause this.  Is my scanner just going bad?  Am I doing something
>> wrong with a setting or something?  Any ideas?  Thoughts?
> The pink hue is probably due to the scanner bar going bad.  Some fixes, which
> did not work in my case, are as follows:
>
> 1. Reset internal chipset:  Plug it in, switch it on, then pull the power
> lead, followed by the USB.  Wait for a minute or longer to discharge, then
> reconnect, power on and try to see if the problem is fixed.
>
> 2. Overheating: More of a problem in the summer.  Use a desk fan while
> operating to see if it makes a difference.
>
> If none of the above work, then the scanner bar needs replacing.  Probably
> time for a new scanner, unless you can find a donor scanner for the scanner
> bar.

Well, bummer.  I was afraid it was going bad.  I knew it moved the light
thing back and forth and all but know there is a lot more to it than
that.  If it was a consistent streak, I'd think a bad CCD or whatever
that chip that grabs the image is called nowadays.  This tho, wasn't
looking like that. 

I may disassemble it again and check all the cables. Disconnect and
reconnect everything and hope for a bad or lose connection.  Now let us
pray. 

Given I only use Linux, know of any good and commonly available flatbed
scanner models?  I'm fine with used ones as long as they work.  I like
the one I got since when I'm done, it stands upright in my closet and
takes up very little floor space.  It does a really good job. I've even
scanned in pictures and they looked good, when it wasn't doing the
streak thing. 

Thanks.

Dale

:-)  :-)