Paper wrinkles

[printr640]

We have had problems with paper wrinkles for some time now usally occurs with 70# text or lighter and with paper thathas not been wrapped. We do have a small amount of wrinkles occassionally on back up with new paper...
Just looking for some input.

 

[RGPW17100]

Press causing this? What press and what type of stock. We used to have problems with Cougar. If you cant back it up right away try putting a garbage bag over it. Could be low humidity doing this. Where are you from?

 

[GazKL440]

What press are you running? Im guessing the 640 refers to a Komori but cant be sure.. We get a bit of wrinkling on really light stocks on our 40" Lithrone, usually from the running wheels and brush wheels being a little too tight, but also from smoothers being fractionally too tight as well... One other thing i check on the feed table is running wheel pressure; i try to have them set up tighter in the middle of the sheet and progressively lighter towards the edges to help ease the air out of the sheet as when it gets trapped under the sheet it will bubble and cause creasing...i also will run light smoothers well up the table to help move the air out from under the sheet before it reaches the head lay.

Hope this helps

 

[Jimbo]

Could be tight edges/corners . Unfortunately I work in a place that isn't temp and humidity controlled so I run into these situations. A little trick I learned back in the day, and this really only works if the press room conditions are warm, is pour a little water on the ground where the sheets are being delivered.

Amazing, but it rejuvenates the paper after the harsh conditions it endures passing the IR's. Makes for easier backup.

Of course this doesn't help you if this is the first pass. So, if this is first pass issues I would immediately jump to the feeder and check tapes, wheels and hold downs. Never had wrinkles on the first pass that wasn't feeder related.

 

[Copper]

Turn all air blast off through the press.

 

[Copper]

This happens on our Man Roland 700. Turn off all air blast through the press. To much air and it will blow the tail end up.

 

[printr640]

640 refers to mitsubishi 6 color 40 inch press. And yes humidity has been very low lately, we were down to 10% @ one point. I believe this to be the problem it comes with this time of year. We have a non climate controlled warehouse and the paper I had trouble with was in said warehouse for quit some time. A new never been opened skid ran fine. However on back up I did have a minor wrinkle that did not affect anything and you really had to look to see it

 

[DanB]

640 refers to mitsubishi 6 color 40 inch press. And yes humidity has been very low lately, we were down to 10% @ one point. I believe this to be the problem it comes with this time of year. We have a non climate controlled warehouse and the paper I had trouble with was in said warehouse for quit some time. A new never been opened skid ran fine. However on back up I did have a minor wrinkle that did not affect anything and you really had to look to see it

You need to get the paper out of the warehouse and into the pressroom a few days before you run it so it can get to the same temp as the pressroom. Changes in temperture will cause paper to dry up or absorb moisture.

 

[MHS]

The main problem we have had with unwrapped paper is dry or tight corners. Trimming the edges usually helps with this. As for wrinkles, we have most of our problems right after the perfector.