Paper requiring a lot more powder

[mazengh]

Lately we aquired a job to print weekly ads with a quantity of over 100,000 2 8 up signatures. The presses we have are two heidelberg sm 102. The powder system is grafix. On this job we are forced to use customer supplied paper which is off course bad quality paper. Not only it doesn't stack well but it requires a lot more powder than we've seen before. Can anyone provide some hints on how we can reduce powder usage. Not trying to save on powder here, just trying to decrease the number of stops and wash on press.

 

[Alois Senefelder]

Set - Off ?-/

Set - Off ?-/

Mazengh,


1) Why are you using more spray powder ?? - a) Is it - Increased set-off using supplied paper ??

b) Then - use correct Ink for this paper.

2) Use larger size (Micron) Powder


Regards, Alois

 

[mazengh]

Like a lower tack ink?

 

[RGPW17100]

Do you know what the stock is? What you might be seeing on your blankets are calcium instead of powder. Seems to me that paper is carrying a lot more calcium then it used to

 

[mazengh]

We are 100% sure its powder because just on this paper type we have to increase the powder.

 

[Cornishpastythighs]

I agree with Alios, seek out a better ink maybe a hard dry or at least have your ink supplier come visit and make a recommendation. Larger Micron will help. If your press is equipped with a IR dryer then make sure it is working properly. Not just heat but air flow also. Check your pile temperatures and make adjustments to your heat/air to give you maximum drying efficiency.

 

[Bob Peterson]

Does the problem paper have more ink hold out then the other papers you normally run? Does it seem like you have to run more water when running this paper? A lower tack ink may help as will a courser spray powder. However, It would be better to know what is so different about this particular paper that is causing the issue.

 

[RGPW17100]

Would be nice to know what the stock it. Could be yupo. If that were the case it would require a lot more powder and the ink might not dry. Some stocks that are high in alkalinity tend to not dry well and have to have more powder. A surface dryer would help for drying but all of this is supposition without knowing the type of stock you are running

 

[DotBox]

The only reason I've ever had to run more powder is to prevent set-off or bricking of the stack, so I assume that is the reason you say you have to run more powder. But I'm also curious why this customer supplied stock doesn't stack well. Is it coated or uncoated? Is it static-y, wavy, or what?

I think a printer has to know what the paper is before he/she can guarantee a successful print run. The manufacturer, grade of paper, type of coating if any, post-consumer waste content (i.e. calcium) and a number of other factors are necessary to determine what ink, solution mix, and drying/handling/racking time is appropriate, and also what to expect in terms of powder usage. Some stocks just require smaller lifts and more time to dry, as well as more powder.

Without knowing the exact details of the paper, I'd be cautious in all respects and if you have to run/deal with more powder, that's just the way it is. If you can find out the specifics of the stock you're dealing with, then you're a leg up and would have a better chance of figuring out what exactly is happening and what you need to do to deal with it.

I hate unidentified "customer-supplied" stock. Always have.

 

[turbotom1052]

you mentioned how the paper does not "stack" well. By stack ill assume that you mean how it jogs in the delivery. Id be working on getting it to jog as best you can. Poorly jogged delivery piles I've found to be more prone to offsetting.