Mimaki has announced a UV-curable metallic ink, MUH-100-Si, designed for use with its UJF-7151plus industrial flatbed printer.
Mimaki says that it has mixed a bright pigment into the ink to create the metallic effect. The key to this ink is the arrangement of the particles within the ink. The printheads used in the UJF-7151plus feature built-in recirculation which helps to keep the pigments in suspension, meaning that when the ink drops hit the substrate the particles naturally create a uniform arrangement.
This printer has six printheads, for CMYK plus white and clear, meaning that if you install this ink then you will have to give up either the white or clear ink and will require a Silver Ink Replacement Kit to flush out the original ink.
Users can choose between a matte foil-like finish or a glossy paint-like effect, which seems to be due to using different curing settings to affect the distribution of the metallic pigment particles. This then affects the way that light is reflected from the substrate back through those particles. As such, this ink should be a viable alternative to using a secondary process such as applying glitter or foil.
The ink itself gives a silver colour but users can achieve a reasonably wide range of different metallic tints by printing coloured ink on top of the metallic ink. The metallic ink can also be combined with the clear ink to produce textured and embossing effects. However, Mimaki does recommend printing the metallic ink separately, which can slow the printing process down. You may need up to three layers – for the silver metallic ink, the colour on the metallic to create tints, and for any non-metallic colour – and this can take up to 54 minutes per bed, assuming that you want good image quality (which seems like a reasonable assumption for value-added printing). Then again, there’s no need to remove the substrate from the printer so there shouldn’t be any registration issues.
Bert Benckhuysen, Senior Product Manager, Mimaki Europe comments: “At Mimaki we dedicate ourselves to providing customers with products that will allow them to stand out within their markets. Not only will the new metallic ink ensure this, but it will also provide a much more efficient way for our customers to manufacture more luxurious and sophisticated products.”
The UV ink will print to a wide range of different substrates and objects for applications ranging from labels and business cards to smartphone covers and product decoration. It appears to perform reasonably well on materials such as polycarbonate and ABS but less well on glass and metal. Mimaki argues that in some short runs it may be cheaper to use this ink than to create a plate or metal mold. Also, it’s worth noting that this ink cannot be used with Mimaki’s Kebab unit, which is a jig to hold cylindrical objects in place. The MUH-100-S metallic ink does not seem to have the same degree of scratch resistance or flexibility as the other inksets offered with this printer, judging by Mimaki’s own test results.
This ink generally seems to have poor resistance to solvent abrasion – meaning that it slowly peels off – but printing the standard LH100 CMYK inks on top can improve this. It fares better in the standard pencil hardness abrasion – rubbing the ink with a nail – scoring 2H, which is reasonable though for comparison the LH100 inks score 5H. And, of course, abrasion resistance of any type does depend on the substrate and how well the ink adheres to it in the first place.
Mimaki has developed an ionizer in the form of a corona unit, sold as an optional extra for this printer, and which is recommended for use with the MUH-100-Si metallic ink. The ink itself is supplied in 200ml bottles. It’s unlikely that Mimaki will offer this ink for its other UV printers because of the requirement for a recirculating print head (where the ink is recirculated through the head itself as opposed to just around the ink supply system).
The MUH-100-Si was officially launched at the beginning of February and should be available worldwide around about this time though this may vary from region to region. Check the mainMimaki website for further details.