DocuColor7000 Overprint on Offset Varnished Printed Sheet

[erikson73]

Hi, can anyone help? My client requested to a 2C (Metallic colour + Black) + varnish using offset for a voucher. After which, we will be required to overprint serial numbering with barcode on it using our Xerox DocuColor 7000 for security purpose.

I am just wondering will the varnish react with the heat from the digital print process and create any undesirable effects on the printed voucher? Or at the same time, will the varnish react with the high temperature and damage the roller or transfer belt housed inside the digital press. Please advise. Thanks a million!

 

[RUsure]

Or, will the overprint "pick" or smear?

 

[billyinlasvegas]

Can you varnish after the piece goes through your DC7000?

 

[arossetti]

I second Billy's suggestion.

 

[CajunPrinter]

DocuColor7000 Overprint on Offset Varnished Printed Sheet

As it happens my XEROX tech is here working on my 7000. I asked him the question.
Though he'd never known anyone that did it he certainly wouldn't do it, I'd would try it either.

 

[CajunPrinter]

To clarify my last statement: I WOULDN'T try it either.

 

[arossetti]

I see no reason why running it on your 7000 before varnish wouldnt work however.

 

[wmwilker]

We are unable to copy anything over pre-printed (press) stock.
Our DC7000 will melt and smear the ink regardless of how long ago it was printed or what type ink was used.
The heat roller will melt the ink

 

[CajunPrinter]

I "overprint" almost weekly on stock supplied to me that has been offset printed.
Never have we had an issue with the ink melting (?) or smearing. I have to believe if ink is melting then, if supplied from an outside source, you are getting stock that is digitally printed.
I don't see how ink can melt, regardless how hot the heat roller gets. Now if you are overprinting and metallic inks are smearing on a particular stock, I could understand. Are you experiencing this on all stocks, inks (pms, process.)

 

[wmwilker]

In the 5 years we've had our 7000 we have NEVER successfully printed on pre-printed stock. Ours will smear or track every time.
Glad it works for you.

BTW these are normal PMS inks

 

[F.I.ImGoingFishing]

First off, If you pre varnish the piece then you are effectivly sealing the surface giving toner nothing to fuse to. You will need to leave a window of no varnish to digitaly print that area. You also want to linit the coverage in those areas that over-print. We have found that areas that are greater than 60% solid do not take toner well.

As for ink smearing when running through a laser, that has to do with types of inks, or rather the waxes contained in them and cure times. Rubber based inks will remelt regardless of cure times and metalics due to the nature of how they set-up will also smear if they were printed on an uncoated stock.

 

[erikson73]

Hi All,

Thanks for the feedbacks an advises.

The reason why we need to varnish the offset printed sheet as there are metallic colour on it. My press operator is experiencing paper jams due to the metallic "powder" sticking onto the roller. This seems fustrating and minimise the productivity of work. As such, someone from my production teamsuggested to overprint offset varnish onto the metallic area to minimise the "powder" transfer. But I am not sure will the oil-base offset varnish react under the high temperature of digital printing and cause the varnish to smear onto the roller and toner transfer belt within the Docu7000. Can offset varnish withstand the heat in digital printing before it reacts? Please advise. Thanks!

 

[nhprinter]

I'm not sure what he means by "metallic powder", but if you add a little overprint varnish to the metallic ink when printing it will dry a little harder. Most of all though, as previously mention, make sure all of the inks(and varnish if you decide to overprint the metallic) are "wax free" and you should be ok.

 

[erikson73]

@nhprinter: sorry, might have use the worng word. What I meant was the tiny particles in metallic ink. Anyway, your reply is defnitely useful to know. Thanks!

 

[arossetti]

What is the possibility of printing digital first, then sending the work to the press?