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Printing on Heavy Weight C1S - The Solution

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Post time: 2013-4-12 13:28:28 |Show all posts
I was asked the following question by my friend Kaoticor in regards to printing on C1S. I thought it would be worthy to publish on Print Planet to try to help anyone else who has run into similar problematic situations such as these. Here's the question from K:
Hi D,
I hope all is well. Would you have a second to provide some comments for me on a recommendation for a process? I am interested to hear what other people reccomend for our current setup.
- What would you request from an ink maker for the following scenario:
--Printing 2 sided work on C1S (coated on one side) paper. One side of the paper is coated and the other is an uncoated. Paper weight is 210gsm. The uncoated side of the paper has almost a matte feel to it.
--First pass on the press is with the uncoated side. An aqueous coating is used and tone value sum is around 300% on some areas, or in other words, some dark colors, almost rich black, on certain parts of the artwork.
--After briefly sitting, the job is flipped and printed on the coated side, also having an aqueous coating applied. It is very important that we do not get any marking when we flip the job. The artwork on the uncoated
side must not set-off on to the front cover, either during turning the job, or just sitting there.
--Lastly, the sheets will have a gloss laminate applied them, utilizing heat of around 90 degrees celcius between a set of pressure rollers.
Thank you if you have a minute to provide your thoughts!
Here's the Remedial Answer:
Number 1) I would first check with your paper rep, paper manufacturer if in fact the C1S is 'sized to print offset on'. Most C1S paper stocks are not sized for printing on. Once you establish that, we can go further.
2) Worse Case Scenario> The C1S is not properly sized for litho, but you are forced to print your jobs on it. However, please check for other paper stocks that are available, in similar basis weights in C1S you are using.
If you need inks, here is what to do. Continue to print the uncoated side 1st. Wow, that is a lot of coverage on the unctd side, but that's what we're dealing with. Get inks that are 100% oxidizing, even inks that go well and above your normal hard surface, synthetic type inks. YOU NEED DRYING! Van Son Tough Tex is a very good can ready ink for your application. If you use another brand, have the inkmaker prepare this formula:
Strong Hard Dry Job Black 100% Solids (No VOC's)  90.00% >>Poly Wax Compound>>2.75% >>6% Cobalt Drier 1.25% >> 12% Manganese Drier 1.00% >> 2.50% >> Chinawood Oil >> 2.50% Grafo or Water Activated Drier. This equals 100%.  
This takes care of the ink portion of it.
1) Add some fountain solution drier additive to your tank. Follow label directions.
2) Use a spray powder in the 40-45 micron size range that is silicone treated.
3) Run very short stacks.
4) Keep your IR dryer unit between 90-95 F.
5) Wind the print loads as much as possible without causing disturbance of print.
6) Wait if possible, a minimum of 12 hours before backing up the coated side.   
7) When backing up use the leat amount of squeeze to get a perfect 'kiss impression'.
Summary: Your ink as described will and should dry up very rapidly on your press. Do not leave it unattended for longer than 1 hour. It that dries up on press, this is ink that DRIES on substrate.
Please let me know if you need anything else.
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