Folding digital printing

[banjoman]

One thing I was told and the salesman didn't mention it, imagine that, is that the paper cracks a lot when you fold a job even on text weight. Don't understand why with a DI wich uses ink but that is what I'm told. Now I'll probably have to buy a creaser, more $$$$

banjoman

 

[LoneGoose]

Re: Folding digital printing

I don't know about DI, but with toner you certainly need to crease. We use a Morgana Digifold to fold digital prints because it has an inline creaser. (This is not an endorsement of Morgana equip. Am just saying you need to crease...)

 

[jlind]

Re: Folding digital printing

Roger:
What kind of digital? The DI doesn't cook the sheet like xeroprinting.
Cooking the sheet makes it crack more, and putting coverage on the fold doesn't help either.
John Lind
Cranberry Township, PA
724-776-4718

 

[banjoman]

Re: Folding digital printing

I'm talking about a presstek digital press. The guy I spoke with said that the waterless ink dries harder and cracks more when folded, even on 70# offset. I have not heard anyone say anything about this but it doesn't seem right to me, ink on paper isn't like toner which I have folded and know how bad it is.

banjoman

 

[jlind]

Re: Folding digital printing

Banjo:
I think that's blowing smoke. Waterless ink is the same as regular ink, just with some additives to make it dewet the silicone non image area. It's the same ink film thickness as any offset ink. To the point: this thickness is very small compared to the thickness of the paper and the paper coating that is doing the cracking. Look to the paper for the source of the cracking. Lots of tech papers on this by Stora and SAPPI. It's cheaper for a paper company to put mineral filler and coatings on the paper than it is to use more fibers (we don't want to cut down too many trees, now do we?) The coatings are applied in layers, sometimes three layers, and when folded, they crack like crazy without very careful scoring and maybe moisturized scoring. Look to the paper. Is there an IR drier on the delivery of your DI? Turn it down or off.
John Lind
Cranberry Township, PA
724-776-4718

 

[cosmo]

Re: Folding digital printing

what kind of folder are you using? one trick is to set the calipers to double the normal size, you get a more rounded fold but no cracking. Also, make sure the grain direction is right, if you are folding against the grain it will crack, you want the grain running the same direction as your fold.

Edited by: max on Dec 14, 2007 8:24 AM

 

[smatros]

Had similar problems, planning to buy the creaser from Graphic Whizard, seen it on Drupa and was impressed of quality.

 

[Internal_R&D_Analyst]

I don't think we've had any issues with several HBG DI's or the Ryobi or KBA Karat. I suppose any ink can crack but think it would be pretty minimal if the grain direct is correct.

If you have a need to perf or cut things down from multiple up the Duplo 645 works well, not as fast a creasers but does eliminate other steps.

 

[RGPW17100]

Graphic wizard scores will help but dont compare to tri creasers you can buy for a stahl or MBO and definatly not compete against letter press. Grain direction will help but different stocks will help more. We were using sheets like altima, titan and other number 2 sheets and found flo has much less cracking and is a #3 sheet. Alot of the cracking you see is not the ink but the paper coating. Even on offset against the grain for cougar cracks real bad without scoring. If you have a Stahl, Baum or MBO I would get tricreasers for your folder instead of the graphic wizard ones.

 

[rcreveli]

We have KM 6500 and use a Morgana creaser the prevent craking. We also use it in place of the pizza wheel scoring system on our sulby 7. It's also great for adding a hinge on covers. We don't have DI so I can't speak to that but I can say the crease has made us a better shop.

 

[che.c]

We run a wee creasematic programmable creaser. Feed every sheet by hand, but it's cheap and got two different size creasing bars for different weights. Tend to get away creasing only stock over 170gsm (as long as the coverage isn't heavy). Above that weight it's essential for us to crease to achieve any sort of good finish.

 

[jdkmfish]

Paper cracking can happen with any type of printing, digital or litho.

You need to watch the grain of your paper as well,
trying to fold against the grain with give you worst results.

A channel scorer is the best for preventing cracking . . .
we use a morgana autocreaser, but started with a handiscore manual machine
called R&B Enterprises HS-100, which goes for about $ 450.

If your volume is low, you can start with that.

If anyone is interested, we no longer use our R&B Enterprises HS-100,
and are willing to sell it, please email me at [email protected]

Thanks
Jim