Canon S820MG Service Manual page 195

When borderless printing on normal paper,
the trailing edge of the paper contacts the
platen absorber and stains the printout.
Uneven density due to sudden release of
trailing edge from roller
Barely perceptible with normal images.
Postcard leading edge curl
Occurs when printing the address side of
the card after borderless printing the other
side. Conspicuous with IJ postcards, but
also occurs with government issue
postcards and KH201 although barely
perceptible.
When borderless printing, uneven print
density occurs about 4mm from the trailing
edge.
Occurs with PR101 and the pattern for
checking striping and uneven density.
Barely perceptible with normal images.
When using VIVID Photo, uneven color can
occur in areas of high density
Problem occurs almost solely with solid
dark color, such as images of night sky.
Other:
1) The occurrence rate of the following problems is very low, and they can be recovered by normal cleaning:
* Color mixing (a issue mainly with yellow).
* Non-ejection (one color of ink is suddenly not ejected)
* Ink smearing (ink concentrations on the face results in long smears on the paper surface)
2) About throughput:
* Throughput is lowered during borderless printing -> since the number of nozzles used to print the leading and trailing edges is limited.
* Throughput is lowered during quiet mode -> since paper feeding operations are conducted slower.
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All The distance between the platen rib surface and
the platen absorber is too narrow for paper
curling during printing.
borderless printing the trailing edge of the paper
may fall into the channel and come in contact
with the absorber.
All Uneven density due to feeding, when the paper is
released by the pinch roller.
All There is friction with the leading edge at the ASF
separation pad when feeding. As such, when the
address side is printed after the reverse has
already been printed the leading edge tends to
curl.
All Based on the amount of curling due to printing,
when printing the end of the trailing edge it falls
into the platen channel. If the paper thickness
lever is adjustment, dot placement is affected.
All Possibility that this problem occurs due to digital
camera (etc.) CCD noise.
ManualsBooks
Have the user understand that although
borderless printing is possible with normal
As such, during paper, it is not recommended.
As per specifications.
When there are problems with leading edge
curl, print the address side of the card first.
As per specifications.
If this is a problem, advise against use of
VIVID Photo. (VIVID Photo is default OFF).