Inks drying Issues

raj9469

Active member
Dear Friends,

I have a Ink drying problem. I have used Vegetable oil based CMYK litho inks on Heidelberg SM74 with Alcohol Dampening on coated paper and PET films. Usually it takes 24 - 48 hours to dry. But this time it is taking more and more time to dry, even more than a week. I am unable to find the reason. Whether can affect? Now it is winter and temperature is 18 - 22C, does it cause slow down in drying?

I cant even force dry it. Is there any other way to fasten the oxidation process of Inks printed?

I have attached TDS of the inks i am using, Kindly refer it. View attachment 10-10- TDS.pdf

Thank you.
 

gordo

Well-known member
Dear Friends,

I have a Ink drying problem. I have used Vegetable oil based CMYK litho inks on Heidelberg SM74 with Alcohol Dampening on coated paper and PET films. Usually it takes 24 - 48 hours to dry. But this time it is taking more and more time to dry, even more than a week. I am unable to find the reason. Whether can affect? Now it is winter and temperature is 18 - 22C, does it cause slow down in drying?

I cant even force dry it. Is there any other way to fasten the oxidation process of Inks printed?

I have attached TDS of the inks i am using, Kindly refer it.

Thank you.

PH and conductivity affect drying times. What's your numbers?
 

Cornishpastythighs

Well-known member
Here are some reasons for ink not drying properly.
Too much water in the ink(Ink taking up too much water)
Having to carry a Thick ink film caused by weak pigment
Humidity too high.
Fountain solution (as previously mentioned)
Poor press condition, rollers,dampening, ink roller temperatures resulting in poor ink/water balance.

As a first step try adding some Liquid drier 2-5% I think the TDS says
 

aqazi81

Well-known member
As other members mentioned, check your fountain solution pH, too low pH will cause the drying issues.
Make sure you are mixing proper dosage of fountain solution and IPA?
 

raj9469

Active member
Dear Alll,
I have checked pH of Fountain Solution, it is reading 6.7. What is the recommended pH level? 4.0 to 5.5? I guess it is higher than recommended. What are the possible problems at this pH level. Kindly advise. . .
 

Cornishpastythighs

Well-known member
From your first post you say you have ran this ink/stock/press combination successfully before so a question would be, what if anything has changed to give you a poor result this time. Has your Fountain solution always been 6.7pH

Some bedtime reading
http://www.printing.org/page/9654
 
Last edited:

gordo

Well-known member
From your first post you say you have ran this ink/stock/press combination successfully before so a question would be, what if anything has changed to give you a poor result this time. Has your Fountain solution always been 6.7pH

Some bedtime reading
http://www.printing.org/page/9654

Where that article says "emulsification" it should read "over emulsification." And raj9469 use your usb microscope to take photos of your halftone dots before and after fixing the issue. You can post here or jus use for your own reference.
 

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