newbie: synchronization of media and image

[garya]

Not sure this is the right forum for this; please redirect me if it's not.
I'm looking at an application using inkjet technology to print multiple passes on roll material, where the web will be fed continuously from one printer to the next. The images are relatively small (e.g. 1/4" x 3" labels) and have to be lined up pretty precisely. Can anyone point me to an explanation of the mechanisms used to do this alignment and synchronize / trigger the start of the print process for each machine?

For example, if one had a roll with adhesive-backed removable labels, how does the printer identify the start of a label? How is the printing action triggered?

Thanks.

 

[richsweeney]

At Signs101, and many on this forum do what I think you are asking. You need a printer and cutter. You can buy 2 in 1 like a Rolland to save space. However I would suggest HP and a Graphtec. You are looking at 15 to 20k for both, plus the software rip. Only buy used if you want to waste a bunch of time.

 

[garya]

At Signs101, and many on this forum do what I think you are asking. You need a printer and cutter. You can buy 2 in 1 like a Rolland to save space. However I would suggest HP and a Graphtec. You are looking at 15 to 20k for both, plus the software rip. Only buy used if you want to waste a bunch of time.

That won't work in our case. We are going to have to custom build / adapt a print line that deposits custom fluids. At the moment I'm not worried about the cutting. I'm worried about depositing ink from separate printers onto the same material in a well-controlled location. An analogy would be a four color print process where there are four printers, each printing one color. How can I trigger printers 2, 3, and 4 to begin depositing ink at the same relative position? Let's say I have a sensor that reads a mark on the web, so I can raise a signal that means start printing. Is there a way to do that? What sort of timing constraints are there? What type of signal is needed?

Also, any information on tolerances / slippage in position on a web-fed machine would be helpful, e.g. 1mm/10m -- so I have some idea how often a registration / timing mark would be needed. How fast can a web-fed machine feed?

 

[richsweeney]

I don't think you will get the register you need that way. You would need print alignment marks like you were diecuting, so the next machine could register from that.
That is assuming that the material did not streach or distort in some way. The closet thing I can think of is a web offset press. However that is only 4 to 8 colors. Are you trying to build a solar receptive material? Then you may not need to worry about registration.