Konica 7100 second pass printing

[COGordon]

Hello Everyone,

I have a Konica 7100. Recently my shop purchased a Skandacor Sleeker. For those who are unfamiliar you print black then run the paper through the sleeker which than applies foil to the black toner. You then run it again through the printer to print the remaining image. Our issue is we cannot run the sheet through a second time and have it line up reliably. Even with the IQ unit on the image stretches and skews. The company that maintains my machine doesn't have any real solutions and has been slow to escalate the issue to Konica themselves. Does any one have any experience running the same job through twice on a Konica 7100.

 

[TJPrinter]

This isn't just a KM issue. When you print and laminate or foil your sheet the heat and pressure will change the dimensions of the sheet. You’re really sucking all the moisture out of the sheets and changing how it will print on the second, third and fourth pass. The larger the sheet the more it will change. Duplexing and laminating or foiling on two sides will make the problem worse. You may need to setup a new paper profile that accounts for the change in paper size to get your crops a bit closer and this may require some experimentation on each stock that you plan to sleek.

When you say it won’t line up reliably what do you mean? Are all four of your crop marks off, by how much?

If you haven’t already done so, talk to Skandacor, they have some very knowledgeable people there.

 

[COGordon]

Thank you for your reply. I have reached to Skandacor and they havent had much advice in this situation. I am attempting to connect Konica with them but it's been a challenge.

Are you familiar with Konica settings? Im not sure I know, besides running the IQ and adjusting imposition on Fiery how to make a change that accounts for stretching.

What I was refering to when mentioned the allignment not being reliable was that there are times that for a few sheets I can get everything to line up pretty well. However the image usually drifts a few mm as the job progresses. the image will skew or twist a bit in addition to drifting on the x and y access.

Thank you very much in advance for any advice you might have.

 

[pippip]

I think you're just experiencing as mentioned. You're printing digitally, then laminating and reprinting, it is going to have alignment issues.

I'd say anything within 2mm is acceptable giving the circumstances.

If you need to get super accurate you either need to move to hot foiling or single up on sheet.

 

[narseman]

We also do sleeking.. with overprint. We have to add a lot of stroke thickness to the foil image, to then print on top with toner, to make it appear to line up better when that kind of accuracy is needed. Toner does not stick well to foil, but it seems to work ok most of the time.
EDIT: Foil special "printable" foil from Nobelus. Has a coating enabling toner to stick.

 

[brettbygrave]

I have done the same, but the only real solution I can recommend is trapping on anything elements that need to touch each other. I did some business cards with full coverage and just some gold sleeking coming through. I had to apply about 0.5mm trapping to eliminate any white areas showing up.

 

[YourCastle]

We also do sleeking.. with overprint. We have to add a lot of stroke thickness to the foil image, to then print on top with toner, to make it appear to line up better when that kind of accuracy is needed. Toner does not stick well to foil, but it seems to work ok most of the time.

I've had to do this with other machines.

While I'm not familiar with the konica 7100, old school "trapping" has been required for a variety of digital presses that I've worked on.

 

[holyoni]

You should do some alignment. So put some marks when doing the first pass. This will be your reference point. Then you will measure them and you should go on the Paper Settings -> Both sides adj. and make the correction.
So you must understand that you stress the paper multiple times and that leads to stretch. So you must apply correction to the print on the second run through the machine.