DI ink pilling

[_socket]

Hi,

When running heavy black solids I get pilling on the tail edge of the solid. I've tried two inks, but no change. Different blankets, but no change. Can anyone give me some ideas to try or to look for? The problem doesn't seem to ever happen to the K control bar.

Attaching dropbox images as site only lets me upload smaller photos:
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[gordo]

Some thoughts.

Piling occurs when ink builds up on the blanket until it eventually lifts off a portion of the image
 or pulls the fibres or coating from the sheet. It can be caused by defective paper coating, wrong ink consistency (drys too fast), inadequate film of fountain solution (running too dry)., improper fountain solution mix, excessive impression cylinder squeeze or blanket wash that renders the blanket sticky, and the type of plate used (smooth grain plates usually pile less).

Try a lower tack or lower set rate of ink, and/or increase fountain solution to plate.

If above suggestions do not work, replace the blanket or try a different production run of paper.

 

[old guy]

i have seen this on the DI. Being waterless you only have tack, roller pressure and roller quality to work with. glaze on the rollers is the usual culprit with worn rollers coming in close second.

 

[_socket]

Thanks for all the posts!

So after close inspection of the first few sheets of the run I noticed under the loop that the paper was actually picking in the area that would then start to pile. I currently run 25c which is the top of the temp range that the chiller allows so can't go up from here. I ran a different premium coated stock and the problem went away vanished instantly. This problem stock was "designed" for digital printers. I'm wondering if the coating that is applied for digital is what is possibly separating from the sheet? I'm going to test a "offset" version tomorrow and see how things go.

 

[Andrei83]

1. Low durability of paper.
2. Dense viscous ink.
3. Low temperature of the ink device to lift till 28-32.

 

[turbotom1052]

Crappy paper with poor surface strength is becoming par for the course these days. Too hard to resist the savings associated with buying garbage. Ive found that if you can just get the press started and running without the piling it can continue to run clean. I suggest that when you have the issue that you thoroughly clean not only the black blanket but any blankets that follow. That sort of piling will continue right on down the line. Once ALL you blankets are clean with ZERO traces of the issue on ANY of the blankets you can often solve your problem by spraying some anti skin spray on the rollers in question. Spray a liberal amount onto the rollers and allow the anti skin spray to work itself into the rollers. The idea is that if you can start out with low tack, the job has a shot at staying clean. You may even have to spray the blanket lightly in the offending area. It will likely require about 25 to 50 sheets on startup to come up to color but it just may allow you to run without the piling issue. It would be wise to keep the press running if possible once the press gets going piling free. If you should have to stop the press for anything but the shortest time you may have to repeat the process.

 

[raj9469]

Some thoughts.

Piling occurs when ink builds up on the blanket until it eventually lifts off a portion of the image
 or pulls the fibres or coating from the sheet. It can be caused by defective paper coating, wrong ink consistency (drys too fast), inadequate film of fountain solution (running too dry)., improper fountain solution mix, excessive impression cylinder squeeze or blanket wash that renders the blanket sticky, and the type of plate used (smooth grain plates usually pile less).

Try a lower tack or lower set rate of ink, and/or increase fountain solution to plate.

If above suggestions do not work, replace the blanket or try a different production run of paper.

I am having similar kinda problem, piling is seen on blanket in yellow ink more than other colours can anyone please help me to come out of this.
Since it is special inks we cant add any unknown additives in regards to Oekotex and other certifications.

Where as other brand inks has no issues on same plate, same unit