Hickeys

[RGPW17100]

15 years ago I dont remember this as a big problem in fact as a teen it was cool to have one. Is it that paper mills are cutting so many corners and paper is not clean anymore?

We are very careful on Cutter Blade maintainence and always back cut stock but hickeys are always there. We almost need a full time person on unit 2 (5 color SM52 using unit one to depowder and catch hickeys) to run the hickey catcher. So what is the deal. Everyone is making cheap paper? We use Cougar as an uncoated and use Flo for our gloss sheet. We even had a run with centura that was problematic. Seems like designers are not aware of this because they sure like to use large black solids and almost never covert these files to rich black. Any ideas on how to reduce this. Are hickey catcher form rollers worth it and if so do you only use them of the first printing unit or on all? Here is what we are currently doing to help reduce this

Back trim all stock with sharp blades tossing the bottom couple sheets on every lift
Use quick release blankets
Make sure we have almost a 4 mm stripe on the forms to help pull crap off the plate.
Try not to buy the cheapest stock whenever possible.

 

[Al Ferrari]

Do you notice any difference in the problem between printing the first side compared to the second side?

 

[richck]

there are alot of places for bits to drop from on a SM52, if you dont look after it.

 

[RGPW17100]

Press is clean as a whistle. We do a good clean up every night all cylinders and the whole system At start up we feed 100 sheets of blank stock with all units on impression to knock off any loose debris that we disloged the night before cleaning. First side is worse for the hickeys however back side has the powder. With Aqueous we run the sprayer at .5 on the first side and 1.0 on the back up. Are hickey catcher rollers worth the cost and the extra clean up time?

 

[Paultheprinter]

Hi there,

I too have suffered major issues with hickeys over the past three years, i never seemed to get these issues before. One problem which i read about was the change from mineral oil to veg bassed inks causing higer tack at point of transfer, how true this is im not sure. Im sure with all the cost cutting measures across the industry that the quality of our materials has dropped and will continue too but there are ways to reduce problems caused by poor materials. What type of hickeys are you getting? flick through the stack and see where the hickeys stared and look for picking at these points, if you cant find them them at these points then it might not be the paper causing these issues, do tape pulls from plate and blanket and look under a powerfull microscope, i use a 50x and most of mine were from dried ink from the prevous units superblues, once they were changed they were 80% better. This is only only one way to go you could try a more lubricating fount soloution or better release blankets, good luck

Paul

 

[madjock]

First of all, are all your rollers in good condition and set properly, a roller which is breaking up can cause plenty of hickeys, also are you sure the hickeys are coming form the stock, I would stop the press and pick the hickey off the plate to try and determine if it is coming from the paper or the ink.
We run our vario rollers on all the time which almost, but not completely elliminates hickeys.

 

[Albert Noel]

we get hickeys when running on flo as well. not exactly a high quality sheet.
as for the knife, try turning your second pile so that the cut edge is always facing you, that way the edge of the blade forces all loose fibers outward and not to the pile face.

ive got as far as hanging tarps over the feed end of the press, it helps collect settling dust and keeps it from getting into the feeder. (its over my fountains as well)


my .02

 

[RGPW17100]

I will examine the hickeys via a tape test. I am guessing the surface coating is picking but until I test it I cant say for sure. Cougar hickeys just as bad if not worse then Flo. We switched to flo because it ran cleaner then Titan, Commerce, Altima and many other cheaper sheets we tried. Flo is a number three but it finishes real nice with little cracking. We starter replacing all of our rollers till money ran out. Only got units 1 and 3 done. Water and ink forms on the rest of the press are about 2 years old.

 

[roy35ka]

Hickeys

Hickeys come from one of 3 sources, paper, ink, or press. The first step is to isolate the problem to one of the 3 sources. If it is the paper, you should have evidence on the blanket. Look at the hickey under 50 power magnification. That tells the story. Can you see fibers? Coating will typically look like a clear glass like particle. If it is ink you should be able to tell from the color. Are the ends of the rollers pitted? Are there "ink cuffs" on the ends of the rollers? We had a problem that sounded much like this. Ours was ink. We switched to a vacuum sealed ink and had a more consistant grind that solved the majority of our issues. I think hickey picker rollers are a waste. They are very hard, so you effectively lose one form roller. Unless you are prepared to remove and hand scrub these rollers regularly, they are just going to pick up the hickey and redeposit it later. Our latest press has Heidelberg Vario dampening. We print on some real junk for paper and have minimal hickey problems.

 

[67drake]

Good advice so far.
Hickies or picking? First you HAVE to determine the source of the hickie. As said above,ink,paper,press contamination.If you are picking off of the paper as you think,here are a few ideas I use.
Make sure you are not running excessive pressure. I have found that on cheaper stocks you may have to squeeze to get good print quality,but over squeezing tends to just break apart the paper surface even more. Squeeze just enough for good print.
If you have a sheet cleaner before the 1st unit,make sure it's working,clean,and use it.
If you have an open printing unit,try running a "wet plate" on the first unit to help clean the sheet. Just run a junk plate on that unit,water forms dropped,and on impression.
If possible,reduce the ink in the problem units. Also,I have had our ink lab put PMS colors back on the mixer to "loosen" them up,this can help by itself. If running process colors out of a can/bucket that are kept in a colder storage area,keep them out by the press to let them warm up before they are put in the fountain.
Faster press speeds will pick more.
Tack cloth the sides of the load before it is run.
The hickie catcher rollers will do you no good if the problem is paper picking off onto the blanket. I have run these in the past,with mixed results,but are more for ink/ink train contamination.
Let us know what you find out about where the source is. (If it's ink or press,I'll give you another list!)

 

[MHS]

THe first thing I would check is the ink roller train to make sure you do not have a roller going bad, or one out of adjustment that is building up ink. Are you running the same color in that unit? Could it be a bad batch of ink that did not get a good grind? Tack to high? have you tried reducing the ink?

 

[Al Ferrari]

Here is an excellent article on the subject. Don't be put off by the fact that it is offered by an after market dampening system supplier. There is a lot of good knowledge in this article, especially in light of various comments in this thread advocating against Hickey Picking Rollers. What this article describes is totally different. But the greatest value of this article is in the explanations given in the last two pages.

http://www.epicproducts.com/assets/MacFee.pdf

Save it to your hard drive and keep it as a reference.

Al

Edit: I was led to this article by a post by Dana in this other thread:

http://printplanet.com/forums/sheetfed-web-offset-discussion/15803-sorsz-conventional-damping

Thanks Dana.