hp 3050 picking

[ar17]

i have an hp indigo 3050 printing on offset substrates from 100gsm to 300 gsm. i hope you can help me identify the culprit or the solution to reduce or eliminate picking or appearance of white dots on colored areas. this problem come and go despite a controlled room temperature and humidity, proper curing of the substrate and there are days that we encounter this and some other days we don't (with the same paper stocks). the thing is we can have a very good prinitng but in a little over 20 minutes after printing, the picking takes place. how can we overcome this picking problem?... help is requested and appreciated. thank you very much

[Curtis Johnson]

You could try these possible solutions:

Increase the Blanket Temperature.
Add Null Cycles.
Increase the Second Transfer Pressure.
Rebuild the inks.
Lower the Total Ink Limit in the files.
Coat the substrates with Sapphire or DigiPrime coating.
Use HP Indigo approved substrates.

[tmason]

Generally, when we see this problem we will no longer use that paper. You can try to do all of the things the previous reply suggested, but it usually boils down to the stock.
Even some of the Indigo approved stocks will pick. We found a few stocks that are bullet proof and stick with those. If our sales guys want to run another paper, we test it first.

We struggled with this issue for several years before we came to this conclusion and now we rarely have to re run a job due to picking.

[blidghie]

Hello there

I agree with tmason's advice. Have you also checked your conductivity of the ink and added more imaging agent to the ink if it is low. just a thought. Good luck

Kindest Regards
Blidghie