gas ghosting

[Gary Wilkins]

I run a sheetfed MAN ROLAND 700 series 6-c alcohol-free. I have to run 4cp, gold, gloss, and dull varnishes. The plan is to run 4cp and gold 1st. Then varnishes. Last year it ghosted on side 2 from side 1. Would alcohol help this problem?

 

[nagrom]

No ! Alcohol free will help you to carry a lighter film weight of ink.Maybe you need to do a double hit of the gold in seperate passes or else the paper is too light for the job.

 

[Paultheprinter]

there could be many reasons for this and there is no easy cure, you will need to get the solvents out of the inks b4 the second varnish pass, either pass job through press again with one unit on impression so you can use the IR driers to try and promote the complete drying of the ink or leave 24 hours between varnish passes and wind the loads, if these affect production to much fiddle around with the ir and air knife and try to get a good amount of ir onto the sheets without blocking the stacks.

Hope this helps Paul

 

[LSW]

Paul is spot on.
Even if you don't have IR, running the sheets back through the press to aerate will help the drying process. I've always found that the ghosting disappears over time. However it's usually long after the job is delivered!

 

[Gary Wilkins]

Thankz for the help. Its about 35M sheet run. I do have IR and hot air knifes.

 

[nhprinter]

Hi Gary,

Without seeing the job it's hard to make a suggestion, but have you looked at the possibility of running the job a different way such as a sheetwise instead of a work & turn? If you can print an entire side with all colors & varnishes without backing it up...that side will not gas ghost. If your varnishes cover most of the sheet it's likely that the other side will not ghost.

The only gas ghosting we've had for years has been with metallics. If you can "seal" the gold with varnish before you back it up, it might not be a problem. If you've had issues with your process inks ghosting you should try another ink.

Dave

 

[MikeG]

In reply to your question regarding Alcohol vs. sub, I don't believe you will see any difference. I have a similar project I do a few times a year and had the gas ghost issue running alcohol. I run the process color then wash up and put the spot and varnish down on the same side ASAP and haven't had the problem again. A pain in the butt, but better safe then sorry. Note, I don't have a dryer and what I'm trying to accomplish with this is sealing in "wet" ink, maybe you would not want to set up your first pass to quickly with to much heat.

 

[Bob Peterson]

Gary,

It makes no difference whether or not you run sub vs. IPA. The IR driers and hot air knives only evaporate the moisture from the sheet this is the only role they play in speeding up drying. In most cases excessive heat is determental and will only exacerbate the problem.

I would recommend the following to reduce the chances of ghosting:

1. Print the heavy side first.

2. Dry the sheets in small lifts, 2-3 inches, keep them in strict sequence for backing up.

3. Allow maximum time (no less then 24-hours) before backing up the job.

4. Wind the sheets as soon as possible after backing up the job to get water and volatile gases out and fresh air in.

5. Varnish in-line when possible. Varnishing after drying often brings outor developes previously invisible ghosts.

6. Choose the correct ink for the paper. Some papers like Cast coated require higher solids ink.

7. Run as little foutain solution as possible. Just enough to keep it from drying up.

8. Keep delivery piles away from excessive heat or cold.

9. Have your ink company select an appropriate ink for the job and stick with it.

10. Do Not add any additional driers to the ink or fountain drying accelerators as this will only increase the odds of ghosting.

Following these rigorous guidelines should eliminate the problems you are encountering. Should you still have trouble your only other option would be to slip sheet the job as this will entirely prevent the ghosting.

Best of luck!

 

[oxburger]

Would alcohol help this problem?

It all depends on how much you drink! A few shots and you may not even care anymore.....

 

[Bob Peterson]

It all depends on how much you drink! A few shots and you may not even care anymore.....

That works the best!!!!!

 

[Xlb]

Wrong !!!!!!!