Grain direction on digital presses

[jlazerus]

We are having a debate about paper grain direction, whether it really makes a difference to prevent cracking, or whether digital presses in general "prefer" grain short or grain long, and why.
Ideas?

 

[Ritter]

Cracking tends to depend upon moisture content in the paper and grain direction. Digital tends to crack no matter what due to the xerography and thermal processes zapping pretty much any moisture in the paper. Hence the need of humidification control to achieve top notch reliable digital printing. If you go to Print this year take a look at how many gargantuan humidifiers are in the Xerox area.

 

[transcorotron]

Yes make diference

Yes make diference

Yes grain direction makes a lot of diference when folding but if not folding it does not make a diference...

 

[Chris_PTA]

On a heavier stock it is better to run with the grain running across the machine. The stock will travel through the paper path with less effort and less jams.

 

[UberTech]

Short Grain for anything over 150gsm. Long grain anything under.

 

[RGPW17100]

It really depends on the machine. As mentioned the sheet for cover stock should conform the the drum. Our indigo runs short grain on cover and long grain on text. Cannon doc 12 seems to want long grain for everything. Curl is the worst part more then graing direction. A curl on cover stock can be a real problem. Folding and scoring on anything but an indigo is going to crack. Even if you get a decent score on the stock the toner will crack.

 

[lensam69]

We have a DC240, and grain direction affects registration on the heavier stock. By running grain short (grain runs across paper path) we achieve the best consistency.

 

[Steve_S]

We have found short grain to be best, especially on cover stock, but even on some lighter materials. Some of it is trial and error for your equipment - folders, scoring, etc. We use a Duplo DC645 to score and have very little cracking issues on folds. Our biggest issue is climate - Colorado is BONE dry!

 

[doubting_thomas]

For us it matters for bindery, as previously posted, but it also matters in order to get the stock through the machine in the first place. Short grain for most heavier stocks seems to work the best whether printing single sided or duplexing. Curl is the most difficult to control because of the odd settings for curl that the Docucolor 5000 uses. A, B, C, D for adjusting is pretty much a crap shoot and if perfecting, the sheet misses one set of decurlers, which can cause jams when the second side tries to go back into the fuser.

 

[X33]

For digital, short grain is better, because the paper is fed by the short edge of the sheet (SEF).

It will crack either way, short or long grain.

 

[Craig]

In order to stop cracking you need some type of creasing. I use a set of Ultimate Scores from D&R Bindery on our Baum 2020. But there are others as well. Grain direction will have very little to do with toner cracking. With the Ultimate Scores I have 99% eliminated cracking even on the rich black solids on 300gsm gloss cover. They actually out performed Tri Creasers when I put them head to head. The Morgana Digi-Fold is a nice option as well.