Rear+Side+Marking

=When printing the first side of a blank page I am getting a mark on the rear side.=


 * Problem:** When printing the first side of a blank page I am getting a mark on the rear side about 1/2 inch from the right side and on the trailing edge. It seems to line up with the exit roller (which is clean).


 * Cause:** I have figured out what is causing the problem--it is not dirty rollers as I first suspected. The problem occurs when I print right up to the 3mm border and the printer is printing on the side opposite the papers natural curvature. When the paper gets to the trailing edge the vacuum pulls the edge down slightly into the borderless ink grooves near the printhead rest position. This causes the underside of the paper to drag on the edge of the groove and that is where the mark is coming from. I am guessing the vacuum is dragging in ink mist and it collects on the edge of the groove.

It appears to me that Canon could improve the platten design to stop this happening. If I build up the ridge between the two grooves with some tape it improves things. Changing the vacuum strength does not significantly change the severity of the mark.


 * Solution:** Make sure you feed the paper the right way up (curvature-wise) so the vacuum does not pull it in and cause the mark. My recommendation is that if you want to do double sided printing dont print up to the 3mm margins (I have to at the moment).