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(June 2006) posted on Sun Jun 04, 2006

How to create a successful match

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By Craig Campbell

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So, you've taken the step — leap may be the better word — and invested in a new wide- or grand-format, digital inkjet printer. Great – now, what are you going to print on? Quite likely, one of the first things that goes on your printer will be a roll of digital, pressure-sensitive, adhesive vinyl (DPSA). Whether you opted for eco-solvent, mild-solvent, full-solvent or UV-curable inks, each type will interact with your media differently and produce different results.

You'll need to learn which DPSA will provide the most consistent return. This column explains how different ink technologies interact with different vinyl types, and the anticipated outcomes. Printer manufacturers' data also explains inks' effects on media, and how that relates to your specific application.

Think ink

Before we talk about ink's effects on DPSA, let’s briefly discuss how each ink technology "sticks" to the media’s surface. All media discussed here are uncoated, and the ink must find a way to bind to the film. For this explanation, we'll group eco-solvents, mild solvents and true solvents together, and discuss how these inks bind differently than UV-curable consumables. Later, I'll discuss how the solvent-ink types differ.

"Solvent" inks are called this for a very good reason – they contain solvents. The solvent and pigment are pre-mixed for two very important reasons — to prevent clogging those very expensive printheads, and to carry the pigment to the vinyl's surface.

Once the ink hits the surface, the solvent "bites" into the media and carries the pigment with it (if you're a fisherman, think of tag-and-release). Once the solvent has done its job, it evaporates, or "outgases," with the aid of heat and ventilation, and the pigment is left buried in the media.

UV-curable inks implement a completely different approach. Instead of a solvent carrier, these ink pigments mix with a polymer-based chemical carrier that, when exposed to UV light, instantly binds and, thus, leaves the pigment in place.

So, in this case, when the ink hits the media surface, it's exposed to UV light and "cures" onto the media surface. The big difference is that the ink doesn't penetrate the vinyl; it sits right on top. Besides being a very cool process, it offers the added benefit of sticking to just about anything, However, I would strongly discourage trying to change the color of the family dog.

Solvent solutions