Why do scanners always cut off one edge of the image?
scs0
noticed that every single one will cut off about a half inch or so
from one side of the image. It seems like scanners aren't designed to
scan to the edge of the scanning bed. Why is that? By using the
corner of the scanning bed you can guarantee that you've aligned the
image properly, but then the scanner will happily cut off part of the
image.
Why do all scanners have this design bug?
Charlie Hoffpauir
I've had three flat bed scanners, and none had that problem. Maybe you
bought poor scanners?
--
Charlie Hoffpauir
http://freepages.genealogy.rootsweb.com/~charlieh/
CSM1
news:204e03d2-3fdf-4ece...@t54g2000hsg.googlegroups.com...
They don't.
My Cannon 8400F does not see 5/100 inch of the sides. In decimal = 0.05
inch.
I know that because I scanned a 6 inch ruler that is scaled in 1/100th of an
inch.
That is a long way from 1/2 inch.
--
CSM1
http://www.carlmcmillan.com
--
Barry Watzman
** Posted from http://www.teranews.com **
Talker
They are not supposed to do that. I've had it happen in my first
flatbed scanner, but not in any other since then. I think that the
higher end scanners don't have that problem but the lower end ones
might.
The reason behind this I think, is that the cheaper scanners
don't have the same precision fit as the high end scanners. I've
found that if you take the glass off to clean it, the plastic guide
that you place the document against comes off with the glass. When
you go to place the glass back on the scanner, it's not an exact fit
so you might be moving the glass a bit too far to one side thereby
moving the plastic guide. That will cause the document to be placed
outside of the scanner's sensor.
If you can move the glass around then so can whoever assembled
it. If they installed the glass too far to one side, then you'd get
the results that you mentioned.
Talker
Mark F
> On Fri, 18 Jul 2008 17:50:40 -0700 (PDT), scs0 <sc...@vol.com> wrote:
>
> >I've owned several scanners over the course of 10 years or so and I've
> >noticed that every single one will cut off about a half inch or so
> >from one side of the image. It seems like scanners aren't designed to
> >scan to the edge of the scanning bed. Why is that? By using the
> >corner of the scanning bed you can guarantee that you've aligned the
> >image properly, but then the scanner will happily cut off part of the
> >image.
> >
> >Why do all scanners have this design bug?
The 5 flatbeds that I have had haven't had that problem to any great
extent, of the two I have now,
to have the problem, but only cuts off a small amount (<.02 inches on
one side only)
However the hp LaserJet 3030 automatic document feeder seems to loose
some on all sides even though it shouldn't miss anything. For
example, when scanning something x long it only see x minus a bit
and looses about .13 on each side. This may be a software problem
since the flatbed doesn't have the issue. However I've tried the
software that came with it and VueScan (8.4.56) and both
loose stuff with the ADF. (Scans 8.50 wide with flatbed and
either software, but I'm not sure how wide the flatbed glass
or scanning element is. Some options even say it is scanning 8.5 wide
from the ADF, but it is narrower than what the flatbed sees.)
Epsom Perfection 3200 Photo says it only wants to scan 8.49 wide.
(The glass is definitely wider than 8.5, but I don't know wide it
actually is.)
More questions:
. why isn't the scanning element wide enough so that everything
on the glass is scanned? If tolerances mean that .02 to .1 inch
is black due to the wider scanning element, it is not a big deal.
. why are the beds 8.5 inches or some other standard width?
They need to be .25 wider so that we can see the covers of
magazines that are folder, stapled, and cut so that the innermost
pages are the standard width.
CSM1
news:c6ia845gqf79k00kk...@4ax.com...
Scanners are 8.5 inches wide because in the United States 8.5 inch wide X 11
inches is a standard letter size paper.
In Europe and other countries, the standard paper is A4 and is 210x297
millimeters, which translates to 8.26 inches x 11.7 inches.
If you were using A4 metric paper the scanner bed would be 1/4 inch wider
that the paper.
Barry Watzman
"standard paper", their equivalent of our 8.5"x11", is a different size.
When using an ADF, normally the scanning element goes to a fixed
position and locks there and the "scanning", when using an ADF, is done
by moving the PAPER while keeping the scanning element (the same element
used for individual sheet feed) stationary.
Mark F
<Watzma...@neo.rr.com> wrote:
> Scanners are made for worldwide markets. In other countries, the
> "standard paper", their equivalent of our 8.5"x11", is a different size.
I'm not sure what your point is. My point was that some source
documents, particularly magazines, exceed the standard sizes.
>
> When using an ADF, normally the scanning element goes to a fixed
> position and locks there and the "scanning", when using an ADF, is done
> by moving the PAPER while keeping the scanning element (the same element
> used for individual sheet feed) stationary.
I'm not sure what you are trying to clarify. My point was that the
particular scanner that I have that has an ADF doesn't scan the full
8.5 inch width that it would scan when the flatbed is used on the
same scanner. It also seems to cut the length. (i.e., it doesn't
matter if the page is 8.5x 10.5, 8.5x11, 8.5x11.5 [all of which are
the supported width and shorter than the supported length], the
two sizes of the document are missing and the length is also shorter
than the actual length.)
I don't see a hardware reason for reduced width and neither does hp.
There might be a hardware reason for missing the leading edge or
trailing edge, but hp doesn't think so.
The hardware is old enough so hp didn't feel like trying to reproduce
the problem.