Ink contamination with paper lint

[CostaRicaPrinter]

Hello everyone,

I haven't been able to find any posts about this, so here goes. I'm printing in Costa Rica, and we have a very limited supply of paper. For book printing we are using a yellowish, lightweight paper that has good body (thick). It prints great. We call it "papel editorial" - I don't know what it's called in English. The only downside is that with 4,000 sheets (22x17) run through the press, the ink is so contaminated with paper lint that the press has to be cleaned, and the rollers removed and physically scrubbed. The paper lint is seen all over the feeder area in great quantities. We've looked for alternative papers, and this is the only paper sold here by several distributors.

Clearly we aren't making good progress like this, but since we export most of our books, the weight problem is a major factor.

I've tried adding linseed oil to the ink which seems to moisten things enough to allow a bit longer run, but we have not solved the problem. Any ideas would be great!

[What is the yellowish paper used for books called in English? ]

Thanks!

Bill
Costa Rica Printer

 

[gordo]

Try running the paper through the press with no ink to clean the paper.

 

[CostaRicaPrinter]

Hi Gordo,

Yes, I guess that will be our only solution. By the way, what is this paper called in English? And how are commercial operators handling this problem? I can't believe everyone is stopping to clean the ink every little bit!
Thanks!

BG

 

[Green Printer]

You are describing unsized paper.
http://en.wikipedia.org/wiki/Sizing

 

[Cornishpastythighs]

If you have enough print units you can put down an overall Litho Sizing ink in your 1st print unit. Basically an ink with no colour, this traps a lot of the debris. This is what is usually used when we encounter a stock that is giving us a lot of hickeys. IF you dont have that extra unit for 'sizing' then you might want to run the sheet through the press and size first then back through with your print.

 

[davarino]

Papel editorial is a grade of paper that is no longer made as an "off the shelf" item for printers in the United States and, I imagine, most "first world" countries.

It is an unsized and uncalendared (or minimally calendared) pulp paper that resembles construction paper, but is slightly thinner. It is the paper that was referred to in the past as "book" paper when contrasted with "bond" paper, which had a smoother finish and which was sized to accept ink from pens. (Write on old time book paper with a fountain pen and you will see what the problems could be.)

This paper works marvelously for letterpress printing (aside from the ink contamination issue) because it compresses nicely... which reduces makeready time. You don't want to use it on letterpress for posters, though. because of the large ink coverage that posters get... resulting in lots of picking. That is why this paper is referred to as "editorial", or as we would say in English, "book".

It's a monster on litho presses because the blankets on the press will pick the loose fibers (lint) from the entire surface of the sheet, rather than just from the 10%-15% of the surface that is inked.

How to get around the picking? I know of several "kinda" workarounds, none of them easy or and all can be efficient only on a small scale:

1. Run it through a water-only pass on your press once to delint as much as you can. (As suggested above.) This is horribly inefficient unless you get really cheap electricity and have slave labor.
2. Reduce your blanket pressures as much as possible.
3. Reduce the tack of your ink. (As you have done.) If you do... you will get that horrible grey to your printed sheets that is so typical of second-world offset presswork.
4. Change blankets to harder blankets.
5. Change your press speeds.
6. Think about using a poster-grade paper, if it is available and sufficiently low priced. (Probably not an option.)
7. Get as large an idler roller as you can for your inking unit. Then, stop the press every one or two thousand impressions for a fast washup of the idler only.
8. Think for ten seconds about letterpress.
9. Consider importing paper. Even the cheap bond grades intended for North American consumption from Indonesia and Brazil are better on offset than "editorial". You may encounter tariff and duties problems with this... but your paper merchant may have a solution for you if you need enough tonnage. (Money talks.) In fact, if you need enough tonnage, you might tip the balance to convince someone to update their equipment. Good paper can be sold in second and third world countries; it does not have to be a luxury if you can get the price on your exported printed products.
10. Prep your paper outside of the pressroom: fan it out (like is done when separating NCR forms) but vertically and preferably on a grill-like surface to catch debris, then run a vacuum cleaner over the edges to catch any lint. Jog it up and do whatever you can to get the dust out before it gets to your pressroom.

Good luck.

 

[tamale]

Instead of using linseed oil, talk to your ink supplier about an recommended reducer.

Tamale.

 

[Green Printer]

Use a High Release fountain solution along with a low tac ink. We have been using this combination very successfully running unsized book paper.

go to shop.bestchemsupply.com contact them I am sure that they can help.

 

[D Ink Man]

Don't be hesitant to add 15-20% of petrolatum to your ink. For the quality of work you are printing it should work well. I'm guessing that most of you print subject is text type.

The other good ideas given here are also wortrhwhile, such as blanking the stock in the first unit to help remove the lint. If not, install a brush type device across the width of your press, before the stock hits the print units. D

 

[Dan Roll]

I'm with D Ink Man on this one, making the ink more liquid will reduce the stresss on the paper surface.

 

[CostaRicaPrinter]

Thanks Davarino - good ideas. I'm thinking about importing paper! No other options here - either heavy, white paper, or editorial - nice and light, and a pain to print! I appreciate your suggestions. BG

 

[CostaRicaPrinter]

Thanks everyone! We are running a one-color unit, so can't dust the paper off with a first head. I appreciate the comments. We'll look into applying several ideas given. Thanks! BG

 

[Tomtech]

There is good advice from all who responded. Davarino suggested importing paper. Perhaps you could get together with other printers to order larger volume of your most used papers. That might bring the price down to cover any tariffs.

 

[CostaRicaPrinter]

Well, we continue the struggle! Tried petrolatum, but had quite severe toning issues (am using a Kompac). We've run whole "towers" of paper through the press to pre-dust the paper, and that helped a lot. Big waste of time. Cannot find any other supplier that brings in the paper we need - since we export books, we are looking for a light weight paper to keep shipping costs down.

Question - will Mineral Oil (from the pharmacy) do the same thing as the petrolatum I used, or is it a bit more hydrophilic? I can get liquid mineral oil for reducing tack.

Thanks!

BG

 

[D Ink Man]

Mineral Oil will murder your body and increase toning if you claim you had it with the petrolatum addition. By the way, how much petrolatum did you add?

D

 

[Alois Senefelder]

Linting

Linting

Hello CostaRica Printer,


Obvious - 1) until you change to a better grade of Paper, Linting will be a major problem.

Some of my ideas to help you -- 1) check the the Plate/Blanket/Impression Cyl. pressures are correct.

2) use a 10% IPA enriched F.S 3) use a QR (Quick Release) Blanket.

4) are you using Metal Plates ? if not, I recommend that you do. 5) what type of Litho Ink are you using??


NEXT - beg borrow or steal 1 - 2 kilos of CSWO INK (Coldset Web Offset Ink) and have a Paper/ Ink trial

Regards, Alois

 

[Dan Roll]

Linseed oil. Anyone who sells paint has it. The best inks used to be made from it. Mineral oil, while used as an ingredient in coldset inks, is not likely to help.

 

[Tomtech]

Mineral oil is the primary ingredient in overnight spray. I wouldn't recommend it for anything else in the printing industry. Linseed oil has been used as base for ink for years. Hence, oil base inks. In your circumstances, there may be no quick cheep fixes.

Tomtech

 

[CostaRicaPrinter]

Thanks everyone for the information. To answer some of the questions:

1) I'm running an AB Dick 385 with a Kompac system. So the water and ink rollers are separate. ALL rollers collect tons of lint. I've tried "thinner" web ink but got a lot of toning.

2) We are using silvermaster plates. Not really viable for us to use metal plates - we are doing relatively short runs (between 500 and 2,000 per plate), and I got rid of my old plateburner, and no one does this size. !!

3) I have used linseed oil to thin the ink, and it has helped. However, I get stripping on my steel ink fountain roller. For some reason the ink dries on the roller and causes stripping. That's why I asked about mineral oil, since I know it won't dry at all.

4) With regard to petrolatum - I didn't think I was using an excessive amount - the ink wasn't 'that' thinned out. But I got immediate toning. Not going to work!

5) I'm using Kerley Ink "Formsmaster", a newspaper / forms ink that stays open a long time and doesn't skin at all. With "normal" paper we can print all week long before we have to clean the press. The ink has been great. The problem is the huge quantity of paper dust and lint that fills the rollers, so that ink/water balance can't be maintained.

Conclusion - we might have to go back to using white paper, in spite of the extra cost, and weight of the books.

I appreciate everyone's help!

BG
Costa Rica Printer

 

[Tomtech]

High lint paper is always a problem for offset. It gets all through the ink and water system as well as all over the machine. After you clean the ink using the cleanup attachment, you then need to use water to clean the lint from the rollers too. You may even need to scrub them with a damp shop towel. It is mandatory that the rubber pan roller and the chrome or stainless ductor roller stay free of ink for the best quality printing. Because you need to soften the ink to prevent paper dust in the ink, you are also reducing the inks ability to withstand emulsification. The ink is becoming waterlogged and piles on the water rollers and perhaps on the other rollers as well making things very messy. Perhaps a paste reducing compound may work better than linseed oil or petroleum.