We have a Canon C1 ImagePRESS that was installed roughly 4.5 years ago. We still use it quite often, despite it requiring several forms of maintenance over the last 6 months. One issue neither ourselves nor our contracted maintenance tech has been able to solve is an issue with certain outputs: quite plainly, we are experience output pages that have an odd C-M-Y-K array of small dots, appearing on the extreme edge of the printed page. They are always the same order, always occur within the same 1-inch region, and repeat on larger sheets approx 8-10 inches apart. Our techs have been asking Canon if they have any ideas of where to start looking into this, and nothing has come back in the three months this has been happening. We already know it's not software-related, because it appears on the test print that our imagepress spits out, and we already eliminated the Q1 Server as well....
These may be the dots that many printers image to record model/date/serial number of the printer for anti-counterfeiting. I thought that they were usually yellow on color printers though. The Electronic Freedom Foundation had something on this (EFF's "Yellow Dots of Mystery" on Instructables | Electronic Frontier Foundation ). But maybe the dots you are seeing are different than this.
It's hard, intentionally, to find info on the dots. I'm not sure if anyone has decoded them or not. But that is assuming that they are "markers" and not an imaging anomaly.
Well, Matt - IMO they're anything but 'code'.... I'll scan the marks/dots into a 100% scale image for this thread so everyone else can see exactly what we're seeing: that might help.
Last edited by Qkarmark; 03-15-2011 at 05:15 PM.
Reason: adding resource image
Yeah, Matt - it's very weird... I wish more people like yourself would chime in and throw around some wild ideas like yours.... it seems Canon is totally in the dark on this one.
It's a rather significant issue too, because obviously we can't run all our work oversized just so we can crop that awful stuff off, and it seems to also affect the back-to-back alignment: it's as though the dots are causing the imageable area to offset in the direction opposite to whichever edge the dots have occurred.
Oh, and one other note: it seems this anomaly rarely (almost never) happens when jobs are run out of the external paper feed...but that has not been extensively tested.
Those are interesting "occurrences" for lack of a better term. I'm at a loss... Might they be used for aligning the drums/gears and be imaging on the paper when they shouldn't be? Is their offset from each other, or in total, the same as the offset on back to back registration?
Hey, everyone... just a little update: our tech returned this week stating he'd heard back from Canon. Apparently he was asked to inspect the drum. It turns out the drum has a tiny blemish on the surface (rather visible to the naked eye depending on how the light reflects on it) that is picking up virtually 100% toner, and dropping it on the page, in all four colours.
He tested the theory by replacing our drum with a different used one and - despite introducing far more imperfections in the output quality - he was able to make the dots go away. Now we're waiting to have a brand new replacement drum and blade installed whenever it ships. I will keep you posted.
It's official: our C1 ImagePRESS is repaired of the weird colored dots. The factory replacement drum was the trick, so the dots are now gone, and we actually have considerably better outputs now too.
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CMYK printing dots anomoly
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