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Risca · #1 (**permalink**) 02-23-2007, 03:32 AM

When using a digital colour copier how accurate is your duplexing, ie. do the crop marks on the front of a sheet line up exactly with those on the back consistantly through a run, or do they vary or do they never back up accurately. What degree of tolerance is there if they don't. We are new to digital copiers and are disappointed with what we are getting.

30YearsandCounting · #2 (**permalink**) 02-23-2007, 04:42 AM

What machine are you using and how far off is the back-up?

steve2112 · #3 (**permalink**) 02-23-2007, 05:57 AM

we have a ricoh 3260 and sometimes the duplexing is off by almost an 1/8. I can make some minor adjust to the otherside but even still it is never accurate but usually when I have a .25 margin things work out ok. Also things that get duplexed on our copier are not critical jobs so i can get away with it. All our other copiers never duplexed well but i find that if you print one side at a time it does duplex a little better and also thicker paper is harder to duplex.

steve

#4 (**permalink**) 02-23-2007, 06:01 AM

Get used to it...
tolerance - about 3mm or so....
It's "hit & miss" throughout a run.
There are usually exercises you can do to bring it in nice and tight.
We keep ours close, cause we run saddlestitch work on it alot. so it's gotta be close.
1/8" would be too far out to stitch.

remember- It is NOT offset

Risca · #5 (**permalink**) 02-23-2007, 11:46 AM

Thanks for your replies.
We have a Canon C1 imagePress, which is a "new generation" machine, that's only just become available in Australia.
http://www.canon-europe.com/For_Work...S_C1/index.asp
The back up of the crop marks can vary by up to 3mm, but some crops could be almost spot on while others on the same sheet can be out by 2mm or more and this will vary during the print run. Also, when we fold a sheet in half for checking there is skew, is skewing inevitable?

#6 (**permalink**) 02-23-2007, 11:57 AM

Quote:

Originally Posted by Risca

....Also, when we fold a sheet in half for checking there is skew, is skewing inevitable?

Yep - more or less.
From my experience with digital.... again it's not offset. :roll: :roll:

Mungo · #7 (**permalink**) 02-25-2007, 02:00 PM

We run a docucolor 8000 and backups usually depend on the stock. We have set both trays differently within the machine but still have to average it out. Light weight from tray 1 and mid to heavyweight from tray 2 but I will still have to offset each stock weight differently in the rip (up to 2mm). I also have gotten used to how far it can go out during a run and compensate for that too. We also have the problem of an A3 coming out at about 418mm width instead of 420mm. There should be more options for a "mechanical" adjustment rather than just software.

GopherBroke · #8 (**permalink**) 02-27-2007, 01:40 PM

Hi Risca

Because copiers run at a high fuser temperature you have to keep in mind that your paper will shrink on the first pass thru a fuser (i assume a loss in moisture content), I have also found that the amount of toner coverage on the paper alters that shrinkage factor as well. I try to do the least coverage first, followed by the heaviest. It appears the more toner the more shrinkage. The heat temperature varies alot during a run also.
Its just a crap shoot and you hope for the best. Sometime it works and other times ...

Gopher

Risca · #9 (**permalink**) 02-28-2007, 01:37 AM

Thanks again everyone for your input.

ATG204 · #10 (**permalink**) 03-06-2007, 10:55 AM

we've had a lot of troubles in the past with duplexing and skew on digital.

Something I didn't know and was told by a xerox employee, if you align your tray say for a heavyweight1 12 x 18, throwing a heavyweight2 12 x 18 through the same tray will not guarentee the same alignment. each tray needs to be aligned for that sized stock, weight and coating. very tedious but in most cases if you're out a mile this is your problem. depending what software you're using as well, i know ours allows for an image shift.

some xerox machines also have a manual skew, something that was adjusted with out my knowledge and was throwing everything out. make sure you find out if your machine has something like that, it causes a lot of headaches and saves a lot of time if you get this skew bang on.

GopherBroke is right about the shrinkage too, something that I haven't noticed drastically but I have noticed losing 1/32" image area on gloss stocks due to slipage, again its such a small amount but it does effect the overall project if someone is just trimming to crops