Cool Cure for Heat Related Issues

Mimaki Introduces a New Generation of Latex Inkjet Printers

About five years ago, latex inkjet printers were introduced to the sign market, rapidly gaining acceptance as affordable alternatives to solvent and ecosolvent systems. This novel technology certainly filled a big void in the market. Any of the curling issues that printers encountered when printing on some pressure-sensitive vinyl films with solvent and ecosolvent inks were resolved, because latex inks are water-based.

Latex inks also dry instantly, if cured at the recommended temperatures. That meant that you could laminate prints immediately after printing. Solvent inks, on the other hand, are not completely cured after printing. Before laminating printing vinyl graphics, shop owners had to wait for the prints to outgas. That takes time…a minimum of 24 hours under ideal conditions. Who has time today, especially when you have an anxious customer breathing down your neck?

Heat Related Problems with First Generation of Latex Printers

As wonderful as the first generation of latex printers were, they were not without their issues. The high heat required to cure inks could cause tunneling of vinyl films on their release liners. High heat could also deform some films and discolor others.

If you had heard about these heat related issues, and they dissuaded you from buying a latex printer, recent technological developments should give you a reason to take a second look. This second generation of inks is also more durable and glossier than precedent versions. The newer inks are also denser and more opaque, which provides greater hiding power when printing on colored stock. 

While latex ink and printer technology has improved in several areas, two key features set the Mimaki JV400LX latex printers apart from earlier generations of latex printers. The Mimaki printers are the first latex printers on the market with white ink.  That development is huge, because it provides the operator with the capability of printing on colored media, reflective sheeting and metalized films, such as RTape’s VinylEfx® print media. It also permits production of double-sided window graphics on clear films.

Low Temperature Cure of Mimaki Inkjet Printers

The other significant difference is that the Mimaki latex inkjet printers cure at much lower temperatures than the first generation systems. The first generation of latex printers typically required curing temperatures of 100°C or 212° F. That’s the boiling point of water. At these high temperatures, the water in the ink boiled and turned to water vapor. Heating also coalesces the individual latex resin particles into one mass and binds these particles to the substrate.

All of this sounds great. But the reality was that what you see is not always what you get. Here’s what I mean. Temperatures of the earlier units could fluctuate greatly. You could set the temperatures in the profile at 212°F. But the actual temperatures at the printer could reach as high 220°F or higher. That’s hot enough to fry an egg! What’s more, after the printer has stopped printing, the media could remain under the heater and continue to cook.  At high temperatures, some media could discolor. Other media, such as polyester film, could permanently deform.

There are a few games that you can play to successfully print heat sensitive material.  You could lower the curing temperature, for example, to 88°C or 190°F.  The tradeoff is that the ink may not be entirely curing and you have to wait for the ink to dry. Another solution is to lower the ink density. The problem is that some colors may look a little washed out. Another fix is to increase the number of passes. While you get a nicer looking print, production time is increased.

With the new Mimaki JV400LX latex printer, you don’t have to play these games. Heating consists of three stages: pre-heating of the media; heating during the print mode; and post heating. Most media, cures at 60°C or 140°F.  Some media, such as polyester, does require curing temperatures as high as 70°C or 158°F. At any rate the temperatures are significantly lower. And when you are done printing with the Mimaki system, the prints are completely dry and ready for lamination.

Because the Mimaki latex printer cure at much lower temperatures than the first generation of latex systems, its energy consumption is significantly lower and consequently its operating cost is lower.

The Advantage of White Ink

The Mimaki JV400LX printers are the first latex inkjet printers with white ink. One of the problems with white inks is that the pigment, which is suspended in water and is heavier than other pigments, tends to settle at the bottom of the ink reservoir. Mimaki’s solution was to incorporate a recirculating feature into their system.

The addition of white ink opens up a number of design possibilities when printing on colored vinyls, clear window films, reflective sheeting or metallic films. After printing a base layer of opaque white you can print colored images on top of it. The white blocks out, where the image is, leaving the colored or metalized media as the background.

When printing on clear films, a white layer allows you to print double-sided window graphics. In imaging on both sides of clear film the printing sequence is to print a wrong reading image; then print block out white; and finish by printing a right reading image.

Mimaki recommends the Color-Logic software, when
using their new JV400LX latex printer. The program allows
creation of white ink masks and gives the user the ability
 to achieve dramatic metallic special effects. 

Color-Logic Software Recommendation

For printing on colored substrates, Mimaki recommends the Color-Logic software, which allows spot printing of white inks to mask the substrate prior to printing process colors.

According to Richard Ainge, the Chief Technology Officer for Color-Logic, Mimaki’s introduction of the world’s first latex printer with white ink capability gives users the ability to achieve dramatic metallic special effects when printing on metallic or reflective substrates. “The Mimaki white ink enables graphic designers to block the effect of metallic substrates where the metallic effect is not desired,” Ainge says. “Using the Color-Logic software to create the necessary white ink masks significantly reduces design time. Using out software with the Mimaki latex printer also enables designers to accurately assess their metallic designs without expensive on-press test prints.”

Latex Ink Advantages

Latex inks feature many of the advantages of solvent inks. Because latex inks are water-based, you have none of the hazards of solvent inks. There is no obnoxious solvent odor. No dangerous VOCs to pollute the environment.  So there’s no need for a special ventilation system. And no hazardous waste is produced. That’s good for the environment and it’s good for the health of the personnel operating the equipment.

If you are allergic to latex rubber, there is no need for you to worry about skin irritation caused by the HP latex inks.  The latex in the HP inks is not the same as natural rubber. These synthetic inks are non-allergenic.

Latex inks are not only more ecofriendly, but they also provide outstanding outdoor durability, adhering to a wide variety of non-topcoated print media used in the sign market. This media includes banner material, polycarbonate film, polyurethane heat transfer films and pressure-sensitive vinyl. 

Latex inks embed into the surface of the substrate. Good adhesion and robust pigments allow the ink to withstand the elements. These inks were specifically formulated to meet or exceed the demanding requirements of the billboard and sign industries.   They are ideal for exterior applications such as outdoor advertising, banners, transit advertising and vinyl lettering and graphics on signs and vehicles.

The second generation of latex inks produces denser, more durable colors. The dried ink is also very flexible, which makes it suitable for vehicle wrap graphics, white are stretched during vinyl application. 

Used for outdoor signage and vehicle applications, vinyl graphics printed with the Mimaki inks provide up to 3 years exterior life without a laminate. Although lamination is not required, it’s not a bad idea. Lamination provides protection from abrasion and chemicals, as well as additional fade resistance from exposure to UV light. With a laminate, durability is expected to be up to 5 years. The reason that latex inks are so durable compared to other types of inks is that the colorant is a pigment, not a dye.

Outstanding durability is not at the sacrifice of production speed or print quality. The latex inks are suitable to print high resolution prints with vibrant colors of indoor applications such as Point-Of-Purchase displays, wall graphics, tradeshow graphics and museum graphics. 

The new Mimaki JV400LX printer features six color print process (CMYK, orange, green) plus white. The orange and green inks, which were not available with the first generation of latex printers, expand the color gamut. That makes matching specific PMS colors or company logo colors a lot easier. In fact, the color gamut for the second generation of latex inks allows the printer to reproduce 93% of the color in the Pantone color chart.

Another difference between the newer latex printers and the first generation of latex printers is that Mimaki has incorporated piezo rather than thermal inkjet printheads. The piezo printheads are permanent fixtures rather than a consumable. That’s a big deal because piezo heads allow for variable dot printing in three different droplet sizes. The result is  smoother tonal transitions and a grain-free, higher quality image. 

Mimaki’s David Robinson says that “the quality and resolution of the JV400LX is so good that you can actually print copy as small as 2 point text. You can’t do that with the first generation of latex printers.”

The piezo printheads in the Mimaki printers also operate at lower temperatures than thermal heads. That lower operating temperature makes them more durable and more reliable.

In manufacturing, time is money. Printing at the 6-pass mode, the output of the JV400LX is about 20 square feet per hour. At the higher resolution 12-pass mode, output is a respectable 8 square feet per hour.  Robinson says that the newer generation of latex printers is 20% faster than the first units that came out.

Conclusion

Improvements in the latex printers certainly warrants your consideration, if your are shopping for a new wide format digital printer. With their cold cure inks and white ink capability, Mimaki has expanded the range of substrate that latex printers can print on. What’s more, the new Mimaki latex printer offers print providers a system that yields a high output without sacrificing print quality.

Vinyl Application Videos

Squeegee Technique. Nothing is more basic in vinyl application than the squeegee. But some squeegees work better than others. And there are right ways and wrong ways to use this simple tool. This video clip reviews squeegee selection, squeegee care and squeegee technique. Click to Link

Wet Applications. Dry applications are typically recommended for most vinyl applications. For those exceptions to the rule, this instructional video explains the right way to perform a wet application. Click to Link

Application of Window Graphics. Installing vinyl graphics on glass can be challenging, because the adhesive aggressively grabs onto this high energy surface. Repositioning graphics on window is generally difficult, if not impossible. This instructional video explains how to dry apply window graphics right the first time. It also describes the necessary steps required for surface preparation. Click to Link

Transferring Frosted Window Graphics Films.  Because frosted window films are highly textured, transferring cut vinyl graphics can be problematic. This video provides direction in selection of the right application tape and how to apply these films quickly, easily and without problems. Click to Link

3-Step Surface Prep. This instructional video describes how to properly clean the surface of a vehicle before applying pressure sensitive vinyl graphics to a trailer or doing a full wrap of a car or van. This three step surface prep involves detergent washing, solvent cleaning and a final wipe down with IPA. Click to Link

Vinyl Application Over Rivets. Applying vinyl graphics on vehicle surfaces with rivets is challenging for most sign makers. Vinyl failures to these surfaces are all too common. This video demonstrates some tips and procedures, used by professional decal installers, which will make these demanding applications easier and more trouble-free.  Click to Link

Vinyl Application to Corrugations. Learn how to apply vinyl graphics to corrugations in a relaxed state. Forcing films into the valleys of corrugations puts too much mechanical stress on the film. Sooner or later, the vinyl will lift or tent in valleys. Click to Link

Applying Air Egress Vinyls. Vinyl films with air egress release liners have almost eliminated bubbles and wrinkles from applied graphics. Air egress release liners with their highly textured surface structure are problematic. Not much will stick to these liners other than the vinyl film. At RTape our best premask solution for air egress liners is a special Conform® tape called 4761RLA. Click to Link

About Jim Hingst: After fourteen years as Business Development Manager at RTape, Jim Hingst retired. He was involved in many facets of the company’s business, including marketing, sales, product development and technical service.

Hingst began his career 42 years ago in the graphic arts field creating and producing advertising and promotional materials for a large test equipment manufacturer.  Working for offset printers, large format screen printers, vinyl film manufacturers, and application tape companies, his experience included estimating, production planning, purchasing and production art, as well as sales and marketing. In his capacity as a salesman, Hingst was recognized with numerous sales achievement awards.

Drawing on his experience in production and as graphics installation subcontractor, Hingst provided the industry with practical advice, publishing more than 150 articles for  publications, such as  Signs Canada, SignCraft,  Signs of the Times, Screen Printing, Sign and Digital Graphics and  Sign Builder Illustrated. He also posted more than 325 stories on his blog (hingstssignpost.blogspot.com). In 2007 Hingst’s book, Vinyl Sign Techniques, was published.  Vinyl Sign Techniques is available at sign supply distributors and at Amazon. 

Slides of Jim's Artwork

© 2016 Jim Hingst