paper wrapping on the blankets

Hi guys,


Have this problem of paper sticking on to the blankets on KBA RA 105. Tried changing different brands of Ink. but the result is the same. this happens only when the m/c is stopped and then started again without cleaning the blankets.It sticks even if the m/c is started immediately ( with in a minute or two).

Checked packing and pressures. All are set exactly to the specifications..

This is happening even with a new set of blankets.

Inks used were from Flint, Sun chemicals and Brancher.

Blankets Used from Kinyo....

The problem is more on paper below 200 gsm and especially where there is more coverage if ink...

Hope to get some useful inputs

Thanks

Anu

 

I take it youve checked the obvious.....Gripper tension/timing? Check from feeder swing arm/ranger drum.

We found this problem 10 years ago when we tried the older Kinyo Titan (green), we then moved to Conti-air 'Ebony' which gave greater release on many very low gsm substrates
Although now we're back on Kinyo's Titan 'Green' due to supply and price which do seem better than the older Kinyo's.

Plus check that your auto-washers are supplying the correct amount of water. We had similar issues with impregnated cloths

 

paper sticking to the blankets, are the sheets pulling out of grippers, are or they pulling off on the blanket(s) like tearing away from the grippers, leaving some paper in the grippers.. i have seen both,, in any case make sure that you are not putting to much pressure between blanket and back cyl.. and check the settings as DATA says,, then move on to ink tack, if ink gets to much tack paper tears can happen, you can reduce the tack of your ink with a good ink reducer,or linseed oil.. good luck.

 

have you tried experimenting with different solvents for your blanket washing device. Ive found that some really aggressive solvents will leave your blankets a bit too tacky! Does this problem still happen if you stop while well into a run after all ink and blanket tack has had a chance to settle in? If all is good once you get into the run then id be looking at ways to get a quicker release by either changing your blanket supplier or running a lower tack ink. You might also want to check your inkers temp. control. experiment by raising up the temp a few degrees to see if this helps with release.

 

Not sure what year Ra 105 you are running but the newer machines at least had the option to start up at a higher speed after the first unit came on impression. This program would sometimes cause problems like this one. Also, there should be an option in the commissioning mode to change when the machine drops pressure on for units ahead of the sheet arriving. Sounds like you just need to have at least one full revolution of fresh ink on the blanket prior to the sheet arriving at each unit.

 

check impression, and if you can put some powder on the blanket just a dusting to see if it helps

 

I think that your problem is only from the inks....but first the question is if you use.. double coated paper.... its chip and very bad
before some years i was have the same problem... when i stop to unload the paper from the delivery paper wrapping !!!!!!!!!!!
the solution i was find was to start the machine again with 20 sheets from another paper !!!!!!!!!!! and use a little value of ink thinner
from then i have better inks and better papers !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

Check grippers, if they are fine it will be one or multiple of the following:

1)Blanket wash to aggresive causing the blanket to become tacky (If you are using a high evaporation type, you will continue to have issues and shorten blanket life)
2)Type of fountain solution not offereing enough lubrication
3)Blankets used have poor sheet release
4) Type of ink used, It is not always tack related either......

 

I've found this same issue with a few of my customers with various presses, regardless of ink tack. Are you running presaturated washup rolls or dry rolls with an auto washer? Also what washup system do you have. The Baldwin units that KBA used after 2006 require a slower drying wash solvent for the autowash system. We were getting the same issues at one of my customers. Check the lead edge of your blankets for wear. If they are wearing first adjust the water cycle up to increase the dry time with your current solvent. I would check the certification of the solvent you are using and check the evaporation rate of it as well. We simply went to a slower drying solvent on one of my customer's KBA105U press and the issue went away. On pressaturated rolls we've had this sheet rollup and blanket wear on several model presses. We simply increase the solvent in the presaturated rolls to avoid the blankets getting sticky and pulling sheets. It doesn't take many washup cycles to wear the surface of the blankets and cause this. You can also look into a harder surface/faster release speed blanket to help this issue. As a test wash your current blankets with a 50/50 mix of bleach and water. This will temporarily harden the surface and increase the release speed and characteristics of the blanket. If this solves your issue step up to the next level of shore and surface hardness of your blankets. Hope this helps.

 

Quickest solution
Spray some Anti Skin/Ink Fresh onto lead edge of blankets just before you re-start the press
Happy Printing

 

this works for me when needed also check ink tack Maybe reduce a little If it still happens after that check grippers and also plus your lays (put more paper in the grippers )

 

Quick fix yes, but in the long run spraying the blankets with anti-skin is bad for your blankets. Aromatic solvents destroy NBR rubber compounds.

 

in all fairness blankets dont last long enough for that to be a problem

 

Check the paper maybe problem is there.

 

Then you should consider using a better blanket. I have customers that run blankets for 2 months running 2 shifts.

 

I do too still takes along time for Solvents to destroy nbr Work it out you wash blankets with solvents

I also work shifts 3

 

Oh really? I happen to have worked for a world wide rubber roller company for 10 years, (the company that made the rollers for your KBA press) I know how aromatic solvents can swell rubber. Try spraying it in 1 small spot on a blanket and let it set there while you take a break or have lunch. If aromatic solvents are in that spray (or roller wash) when you wipe if off you will see a swollen area. Even if it goes back down it still has broken the cross linking that keeps plasticizer oils in the rubber. I have demonstrated this many times to customers that were using harsh solvents and often you will see swell in a short time.
Not to mention, every time you spray that blanket that spray (or solvent) goes into your roller train reducing your ink, it can cause problems with your plates and can end up in your fountain solution. It is not a good practice, best to find the root cause of why this is happening.

 

this works for me when needed also check ink tack Maybe reduce a little If it still happens after that check grippers and also plus your lays (put more paper in the grippers )
When needed being the point Calm done Whats needed to get the job done Customers dont need excuses

 

hi anumenon2
you not mention here how u then sole ur problem..
All post are useful, but i know u get nothing from ur problem.So my opinion is this at make ready time u lose pressure between blanket and impression 2 point more than actual pressure,After make ready , in running adjust actual pressure.Try it, paper will never stick on blanket.