How a UV-Curable Inkjet Printer Works: What makes a UV-Curable Ink Printer Function? What makes a UV-Curable Ink Printer Function?

How a UV-Curable Inkjet Printer Works: What makes a UV-Curable Ink Printer Function?

If you thinking of purchasing a UV-curable inkjet printer, you might like to know what kind of technology is inside.

Digital printers, screen printers, offset press commercial printers, sign shops, and photo labs primarily want to produce images that satisfy their clients and thereby bring in a profit for everyone concerned. So the results of the printing are what count. It is rare that a print shop owner or manager has time to learn what is going on inside the machine, other than the obvious need to know enough to properly operate the printer.

But all kinds of interesting technology are inside a UV-curable flatbed printer. If you are seriously thinking of purchasing a UV-curable inkjet printer it is expected that you will visit trade shows and a manufacturer’s or distributor’s demo centers too. Before you make your actual purchase it is essential that you visit companies that have UV-curable inkjet printers at work.

So let’s look at a UV-curable printer from the point of view of what an end-user, who is thinking of buying this printer, needs to know.

efi VUTEk 3r UV printer. Photo: FLAAR-REPORTS archive.

What features and factors to look for when making your Short List of brands and models to consider buying

Printheads as one factor of Print Quality

There are subtle differences between some printheads; dramatic differences among others. So a printhead is a crucial component in a UV printer.

If you are a print shop owner, manager, or operator, it definitely helps to know the pros and cons of the printheads that are inside the printer(s) on your short list. You do not need to know whether it is a side-shooter or top-shooter or shared-wall (leave that to the engineers). What you need to know is how robust they are, how often will they fail, how long does it take to replace them, how long the warranty is.

efi VUTEk 3r printhead alignment. Photo: FLAAR-REPORTS archive.

What part of the Printer System Moves?

When you visit a major trade show you may notice that the relationship between the positions of the printhead and the media vary. There is no one single technology of media-feed that has become de-facto standard. Each printer integrator has done their best to maximize the benefits of whatever feeding mechanism they have decided on. There is no one system, which is perfect, and no system (so far), which has enough serious downsides so as to suggest that you should always avoid it.

Holding stationary materials or transporting moving substrates impacts on image quality. In a regular solvent or aqueous printer the printheads go back and forth on the X axis. The media is transported incrementally by being pushed or pulled along the Y axis. Most of these printers have optional settings for bi-directional printing (faster) or uni-directional printing (tends to be higher quality, but slower).

AGFA Anapurna H3200i LED-UV printer. Photo: FLAAR-REPORTS archive.

Anatomy of the flatbed feeding and take-up system

When you print with a water-based or solvent ink printer, the media or substrates are made for feeding through such a printer. The solvent printer manufactures know more or less what kinds of materials will be fed through their printers, so they can arrange the pinch rollers and all the rest of the feeding system to accommodate these materials.

But with a UV flatbed, people may run ceramic tiles, glass, or wooden doors through the printer. The manufacturer can’t be expected to design a special feeding system for each coefficient of friction of the surfaces of these often radically diverse materials. So some materials feed better than others

But even once the material is printed, it has to move all the way through the system and out the other end. A 9-foot length of wood, Styrene, Sintra, foamcore or whatever needs somewhere to go. This somewhere is the take-up table.

RICOH Pro TF6250 flatbed UV printer. Photo: FLAAR-REPORTS archive.

How is the Material Held Flat?

There are several ways to hold rigid material flat:

  • A vacuum table
  • Pinch rollers

Pinch rollers are as much for feeding the material as they are for holding it flat. Pinch rollers usually work in unison with a grit roller. The pinch roller is on top; the grit roller is at the bottom. But there are many variations and size differences of these roller systems.

Vacuum tables can be very expensive, as in five to fifteen thousand dollars, or more, depending on size. Vacuum tables are not as effective as you might wish; a vacuum table can keep a piece of foam-core from sliding, but a vacuum table can’t hold a warped foam-core totally flat. In other words, a vacuum table does not suck most materials totally flat; at best it holds them relatively flat, and keeps them from sliding around.

efi VUTEk 3r UV printer pinch rollers close up. Photo: FLAAR-REPORTS archive.

UV-cured Ink

UV-curable ink has been used for many years in the screen printing industry. But getting the ink to jet through a piezo printhead, accommodating the speed, and a host of other factors, was not easy.

When hit by UV radiation, UV-curable ink becomes a solid instantly. Once it is no longer a liquid, it can’t enter the pores of the material. Since the material usually is solid, and has no ink receptor layer, the ink stays on top of the material. Indeed you can run your fingers over the image and feel the ink.

A.T. Inks UV inks. Photo: FLAAR-REPORTS archive.

LED and Mercury Arc Lamp on the field

Production expectations as much as the technology dictate the uptake of LED and the speed with which it replaces Mercury Arc curing.

But its just a matter of time before LED technology can match Mercury Arc curing’s performance. When it reaches that point it will cease to be viable, but that point is still on a far horizon.

Mercury Arc lamps are ideal light sources for applications that require high intensity spectral lines emitted in the deep UV to visible light regions. Their unique UV emission spectra make them popular for unique applications that need enhanced UV output such as UV spectroscopy, UV curing and other industrial processes, and environmental and medical applications.

LEDs are based on semiconductor technology. Specific wavelengths are directly emitted by the current input. The spectrum is a quasi-monochromatic radiation in defined wavelengths, e.g. 365nm, 385nm or 405nm.

JHF R3700 UV lamp. Photo: FLAAR-REPORTS archive.

Protecting against Static Electricity

When the material receives a static charge then the entire surface of the printer attracts ink. The ink is drawn to the entire surface of the material, even outside the area of the intended design.

Static charge will be worse in dry environments (such as during winter with central heating), or in an area with rugs, or if the material itself comes with static charge because it is rubbed (while cleaning, for example).

To protect against build-up of static charges on the material most printers are grounded and some printers have static bars.


Every aspect of UV-curable ink printers has advanced in the last years. Ink formulations and printhead engineering are leading the way. In other words, the ink used today is dramatically better than the ink first offered in 2001 and 2002. Manufacturers now see a growing market for their products and are willing to devote R&D dollars to make products tailored for the needs of inkjet printers, such as smaller size, drastically lower prices, and less heat emission.

AGFA JETI Tauro H3300 LED-UV combo printer. Photo: FLAAR-REPORTS archive.

Rate this item
(0 votes)

Leave a comment

Make sure you enter all the required information, indicated by an asterisk (*). HTML code is not allowed.

Recent Posts

Keep up with the latest trends about de digital printing industry and learn more about different technologies, equipment, media & substrates, inks, etc.