[sane-devel] Canon laser multi-functional support: MFNP protocol

[Michael Shigorin]

On Mon, Jun 22, 2015 at 02:58:48PM +0300, I wrote:
> > The MF6100 series is not listed, but it again might be quite
> > possible to get it to work.
> The same almost white image as with 8540:
> http://fly.osdn.org.ua/~mike/tmp/sane-pixma/Canon-MF6140dn-scanimage.ppm.xz

Silly me, it wasn't "almost white" but rather a valid scan of
the scanner's background!  Managed not to check the actual page
is in place, sorry for being *that* stupid that day...

Retested as of RELEASE_1_0_24-296-g0655b05 and these are the
results with a USB2-connected crop of Canon devices:

MF8540Cdn: scanimage OK, xsane OK (75/150/300/600, colour/bw)
  (at least "Good" by me)

MF6140dn and iR1133if: scanimage/xsane OK _BUT_ only once, sort of
  (might be "Basic", don't know if this passes for git)

Now there's a problem with 6140 and 1133 that looks like this:

- scanimage produces a file (which is fine);
- second scanimage in a row hangs;
- xsane hangs too when trying to preview/scan;
- turning "remote scan" off and on is not enough;
- turning the device off and on (with subsequent
  selection of scan mode plus "remote scan") helps;
- scanimage would hang the same after xsane;
- several consecutive scans using a running xsane
  instance are OK (e.g., different density).

6140 also exhibited weird behaviour at 600dpi (the sound's also
different from 75/150/300 which scanned just fine): the head
might have been hitting the edge for a second or two with the
result being gray bands along the scanning direction at the end
of the file, I've uploaded a (8Kx5K) sample here just in case:
http://fly.osdn.org.ua/~mike/tmp/sane-pixma/Canon-MF6140dn-xsane-600dpi.jpeg

1133 didn't hit that (the 600dpi sound is also different) but the
image quality suffers from some kind of a "cellular" effect, see
http://fly.osdn.org.ua/~mike/tmp/sane-pixma/Canon-iR1133iF-xsane-600dpi.jpeg
(300dpi and lower are fine though).

Again, 8500 had neither of these problems for me now --
never got stuck whatever scanimage/xsane/scanimage I did,
the image wasn't distorted, the head didn't hit anything.
At least so far. :)

Thank you!

-- 
 ---- WBR, Michael Shigorin / http://altlinux.org
  ------ http://opennet.ru / http://anna-news.info