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Digital Inkjet Printing: What's All the Fuss?

Copyright © 2014 by Davis Multimedia, Int'l. All Rights Reserved.
As Printed in July 2014, Volume 40, No. 1 of The Engravers Journal
Some digital inkjet printers are capable of printing 3D effects and raised lettering and Braille for ADA signage. Photo courtesy of Direct Color Systems, Rocky Hill, CT.

   I'll make a wager that 60% of the people reading this article own at least one inkjet printer. You probably have an inkjet printer right on your desk or credenza and another one (or more) elsewhere in your business, especially in the sublimation department. By the way, the 60% figure was published by printer manufacturer Hewlett Packard which claims that’s the market share of inkjet printers vs. laser printers.
   Today’s printers are unbelievable. Unlike just a decade ago, you can buy an inkjet printer that’s lightning fast and produces incredible high-quality, full-color images. Most unbelievable of all is that you can buy one of these amazing printers for less than $200.
   So although almost everyone has one of these awesome printers on their desk, we can’t use them to personalize the thousands of items we sell to our customers. Unfortunately, we can’t buy a $200 off-the-shelf printer from Staples or Best Buy to use to imprint golf balls, award plaques or ADA signage, but the good news is that a whole host of high-tech printers is now available for doing all of these things and more. Digital inkjet printing technology has arrived in our industry and its arrival is something for everyone to learn about and explore.
   Perhaps the biggest drawing point for digital inkjet printing is the ability to produce dazzling, full-color, photo-quality graphics on a huge variety of materials and items. Just a small sampling of what digital printing can be used for includes awards, promotional products (including three-dimensional items like thumb drives, pens, phone and tablet covers, laptops, golf balls, etc.), banners, signs, POP/POS/trade show displays, window signs, labels, decals, magnets, postcards, fine art reproductions, fabric décor, etc. Some of these printers are also capable of creating unique textured 3D effects and raised printing, e.g. for creating Braille and raised lettering on ADA signage—the list literally goes on and on.
What is Digital Inkjet Printing?
   Today, most of us are aware of the difference between analog and digital technology. Analog technology is defined as a continuously varying event such as voltage or pressure to transmit data, whereas a digital signal is either on or off. Analog printing methods reproduce images by creating a copy of a primary image. Lithography, for example, uses images on plates to transfer ink to print substrates. Screen printing involves using film positives and negative stencils of the original image to create prints. Both of these methods, and others such as flexography and etching, reproduce images from a master image.


This wide format sublimation printer from Mimaki USA, Inc., Suwannee, GA, uses dye-sublimation ink to direct print on pretreated fabrics.

   Digital printing, on the other hand, assembles each image from a complex set of numbers and mathematical formulas. The images are created from a matrix of dots or pixels through the process of digitizing. The digitized image is then sent from a computer to a printer which uses ink or toner to print the image.
   Dye-sublimation is a digital printing process and one that many business owners in this industry are either using or are at least familiar with. This process involves using a digital printer to produce an image in reverse on coated transfer paper using special sublimation inks. The image is then transferred from the paper to the substrate using a heat press which causes the dye to permeate the substrate and solidify into the fibers. Because sublimation is a dye process, it only works with dye-receptive materials such as polyester fabrics and polyester-coated materials.
   Sublimation and digital inkjet printing share many of the same advantages. A major difference is that with digital inkjet printing, the image is printed directly onto the substrate—there is no transfer medium involved. In addition, digital inkjet printers can print on many different materials—glass, ceramic, metal, plastic, wood, vinyl, etc.—without the limitation of requiring a specially-coated material surface.
   Digital inkjet printing (sometimes referred to as direct print) has the potential to offer many advantages to people in the personalization business. For example, there are minimal setup costs so you can print small quantity orders very cost effectively. It’s also possible to print millions of colors in one pass and you can achieve fantastic image detail with pinpoint registration accuracy. Achieving multiple colors with screen printing, on the other hand, is extremely expensive and the process requires high minimum order quantities due to the high setup costs for each image.
   Digital printing could be a perfect fit for businesses involved in personalization and it could be one that opens up many market opportunities. Read on to find out more about this interesting—and growing—technology.
Digital Printing Equipment
   There is an extensive selection of digital printing equipment available, including various sizes, configurations, options, capabilities, etc. Here is an overview of what’s out there.
   Digital inkjet equipment typically includes flatbed printers, roll-fed printers and hybrid flatbed/roll-fed printers. Roll-fed printers utilize rolls of flexible substrates, like paper, canvas, vinyl, film or heat transfer material, which is fed into the printer during printing. With a roll-fed printer, you print directly onto the substrate and you can also print on materials that can then be mounted on a rigid substrate to create the final product. For example, you can print directly on banner vinyl to create banners and you can also print images on self-adhesive calendered vinyl which can then be mounted on a window, foam board, sign blank, etc.
   As the name implies, flatbed printers have a flat table where you place the item to be printed and the inkjet printheads move over the stationary item to print the image. Direct-to-substrate flatbed printers are capable of printing directly on rigid substrates so there is no need to print an image and then mount it on a rigid blank. A big advantage of flatbed printers, at least for some applications, is that they can be used for printing on bulky or dimensional items that cannot be fed through a roll-fed system, such as golf balls, poker chips, pens, phone covers, sign blanks, awards, giftware items, promotional products, etc. A potential drawback of a flatbed printer is that it usually has a larger footprint, particularly with the wide format systems, so these printers typically take up more room in a shop. On the other hand, flatbed printers tend to have a limited printing area because they are limited by the working range of the machine, unlike roll-fed printers which can accept rolls of material in exceptionally long sizes.


A digital printer with both print and cut capabilities allows printing items like decals and contour cutting them on one machine. Photo courtesy of GCC America, Inc., Walnut, CA. One of the applications for flatbed digital inkjet printers is printing colorful designs on 3D objects, such as phone covers. Photo courtesy of Mimaki USA, Inc.

   Hybrid printers are also available which are designed to offer the both of best worlds with both roll-fed and flatbed capabilities. This type of printer can hold a roll of material and also convert into a flatbed unit, e.g. with front and rear flat folding tables.
   In addition, some digital printers are equipped with both printing and cutting capabilities. The concept behind this type of printer is that you can print an image on a material such as vinyl and then use the same machine to contour cut the printed image, as opposed to printing the graphic on a printer and then cutting out the image on a separate cutting plotter or laser. You can use a combination printer/cutter for applications such as printing banners, signs, decals, labels, posters, vehicle wraps, floor graphics and apparel decoration in unique shapes including logos and other graphics. For example, you could print the Apple logo on vinyl and then cut out the apple shape using one machine.
   Another type of digital printer available is known as a direct-to-garment (DTG) printer. The type of digital inkjet printers discussed so far in this article are typically not designed to print directly on fabrics, such as cotton T-shirts, canvas bags, etc. For apparel decoration, these printers can be used to print color images on heat transfer material which you then apply to the garment using a heat press. A DTG printer, on the other hand, is a digital printer developed for printing directly on fabrics. With a DTG printer, you load a garment into the printer, print the design directly on a garment and then use a separate heat press to heat-cure the ink. DTG printers offer several advantages, e.g. it is a more economical method for small quantity orders compared to screen printing, it produces a soft “hand” unlike some heat transfers which have a rubbery feel and, unlike sublimation, which can only be used on synthetic fabrics, DTG printing can be used on any fabric. In addition, although you still need a heat press to finish the product, the ability to print directly to the fabric eliminates the middle step of printing a transfer, trimming it and positioning it on the garment. As technology continues to develop, DTG printing is becoming a primary method for customizing wearables with bright, crisp, colorful images.
   There are also wide-format roll-fed and flatbed digital inkjet printers available that work with sublimation inks. Some of these specialty sublimation printers can print sublimation inks directly onto polyester-based materials after which you use a heat press/source which causes the dyes to migrate into the fibers of the fabric. With some printers you also have the option of generating sublimation transfers the traditional way, i.e. you print a reverse-reading image on transfer paper and then use an external heat press to transfer the sublimated image to the garment.


 

 

The 1024 UVMVP is a flatbed printer featuring a 10” x 24” print bed available from Direct Color Systems.

Signage is a major application for digital inkjet printing technology. Photo courtesy of GCC America, Inc.

    As with any type of personalization equipment, specifications such as the maximum material width, maximum print width and maximum material thickness are important considerations and there is a huge selection of sizes to choose from. For example, on the smaller end there are flatbed printers available with print areas of around 12" x 11" x 4" thick to 24" by 16" x 6" thick. On the very large end there are wide format (loosely defined as those with a printing width of 17" or wider) roll-fed printers that can handle materials up to 200"+ wide. And there are many machine sizes in between. If you are interested in purchasing a digital printer, you will need to know what you are going to use it for before making a final purchase decision. A small flatbed unit, for instance, is a good choice for printing items like small signage, phone covers, golf balls, pens, awards, giftware, etc., whereas a large roll-fed printer allows entering different markets with the capability of printing items like large posters, vehicle wraps, “building wraps,” transit advertising, banners, trade show graphics, etc.
    Two other major printer specifications are print resolution and print speed. These printers are capable of achieving incredible detail in designs and photographs, and you can adjust the resolution for the job and the material being printed. These printers are also incredibly fast with some claiming maximum printing speeds of over 1,000 square feet per hour. One DTG printer manufacturer claims that the company’s fastest printers are capable of laying down a typical 12" x 10" image on a light T-shirt in about 20 seconds. (Like laser engraving, the higher the resolution, the slower the printing speed.)
Basic Ink & Printing Technologies
    The types of inks and printing technologies that digital printers use can vary greatly from printer to printer and can get somewhat complicated. Here is a basic overview of what you need to know to get started.
    Digital printers are generally available as a four-color printing system, six-color printing system or eight-color printing system which refers to the number of inks (cartridges) the printer can use to print images. In simple terms, a four-color printer uses the traditional four process colors of cyan, magenta, yellow and black (CMYK). In theory, you can reproduce virtually any color using a combination of the four CMYK process colors. However, those of you who have experience in color matching know that CMYK tends to fall short when, for example, your image consists of human flesh tones or items that are “fire engine red” and other shades. To get more pleasing and accurate color renderings, it helps to add a few more colors to the CMYK mix. In answer to this, printer manufacturers have added additional printheads to their printers. A six-color system uses CMYK in addition to two “light” colors, usually light cyan and light magenta (Lc, Lm); and an eight-color printer uses CMYK in addition to four light colors, including light yellow and light black (Ly, Lk). However, increasingly you have the option of choosing other ink configurations where some of the light colors are swapped for other colors, such as white, clear or metallic. For example, you can purchase a six-color printer with CMYK plus white and clear (transparent) inks.
    One problem common to all printing processes has to do with printing on various colored substrates. Many inks are slightly transparent, so if you apply the transparent ink onto a colored substrate, the end result can be an image showing the blend of the ink color plus the substrate color. As an example, if you print yellow ink onto a blue shirt, the result can be a green logo (blue + yellow = green).
    A simple workaround for this problem is to first apply a layer of opaque “white” ink to the substrate, then overprint the white area with the desired color. Many of the digital inkjet printers available today are capable of printing white ink. Until recently, the ability of digital printers to print white ink has been a challenge and, in some cases, impossible. Among other problems, white ink needs to have a high degree of opacity in order to cover non-white substrates, but increasing the opacity turns it into a thick ink that can play havoc with inkjet printheads. White ink also needs to be translucent enough for use in backlit applications. Recent advancements in ink, printing technologies and the hardware itself, however, have led to the development of white ink that manufacturers say now works well in digital printers.
    The ability to successfully print white ink has several useful applications, including the ability to create unique types of transparent and backlit products. White ink can also be used by itself on dark substrates or serve as a base coat on non-white substrates on top of which other colors can be printed. The clear ink is used to create different finishes, such as matte or high-gloss finishes, and also adds additional durability.

GCC America, Inc. recently introduced the JC-241UV which is a hybrid printer that also features both print and cut capabilities.

Ink Types
     Digital inkjet printers are designed to use a specific type of ink of which there are several available. Three of the most common inks used are solvent, eco-solvent and UV-curing inks. The difference between these has to do with how they cure and change from a liquid to a solid after they dry or cure. Note that digital inkjet printers are generically named for the type of ink they use, i.e. they are referred to as a solvent printer, eco-solvent printer or UV printer.
     Solvent inks have been the traditional inks used in digital printing. Solvent inks contain pigments (as opposed to dyes) in addition to large amounts of organic solvents. These solvents evaporate and create strong odors and hazardous fumes requiring a specialized ventilation system in the printing area in addition to careful handling and disposal. The advantage of solvent inks, however, is that they create an extremely durable print that is outdoor weatherable, waterproof and UV safe without the need for a special coating, making them a good choice for vehicle wraps, billboards, banners, adhesive decals, floor graphics, etc. When you see a bus or other vehicle decorated with graphics that look as though they have been painted over the entire vehicle, it’s most likely a wrap that has been printed on a solvent inkjet printer.
     In more recent years, eco-solvent inks have been developed as a green alternative to solvent inks. Eco-solvent inks solidify by drying as the solvent evaporates, but they generally contain smaller amounts of organic solvents that emit less odor and are gentler for people and the environment. As a general rule, eco-solvent inks can be used outdoors but are not as durable as solvent inks. According to some sources, eco-solvent inks will last up to six months unprotected outdoors, depending on the environment, and up to two years if a clear coat is applied over the printed image.
     The most recent type of ink to enter the digital printing market is UV-curing ink. There have been (and are) many new UV printers introduced, making this technology one that is gaining a lot of ground. Instead of having solvents in the ink that evaporate into the air and absorb into the substrate, UV inks are exposed to UV lights that are built into the printer which quickly cure the ink to turn it from a liquid to a solid. This technology offers several advantages, including quicker curing times, no noxious fumes and fewer emissions of volatile organic compounds into the environment. Previously, if you wanted to print on an odd shape, solvent inks were the way to go. However, recent developments in UV inks have made them flexible which enables them to conform around odd shapes and corners without cracking or chipping. Reportedly, UV inks will last three to five years outdoors. UV inks are also suitable for a wider variety of substrates because, unlike solvent inks, they don’t have to penetrate the material because they dry by exposure to UV light. UV printers can print on materials like plastic and porous substrates like paper with vibrant, crisp images.
     Another type of ink used in digital inkjet printing is known as aqueous ink. These inks are water-based and are available as either a dye or pigment ink. Dye inks will fade due to UV light exposure and are not waterproof but they are noted for strong colors and the ability to print small dot sizes which creates a high-quality image. These inks are suitable for applications in dry environments, short-term use in UV light or for indoor lighting only. Pigment inks are considered short-term waterproof and are stable in UV light allowing them to be used for applications such as window displays. Both dye and pigment aqueous inks can only be used on media that is manufactured with a special coating.


 

Mimaki USA, Inc. offers the UJF-6042 A2 format UV-LED printer for printing on a wide variety of materials and objects.

The mP10i is a direct-to-garment printer available from Anajet, Costa Mesa, CA. This unit has a maximum print size of 14” x 18”. Optional print platens for hats, smaller items and sleeves are also available.


What About Price?
    As you can see, there are many different options and variables involved when it comes to choosing a digital printer, including the style of the printer, the size, the ink technology used, options and more. There are also many manufacturers of digital printing equipment. All of this means that prices for digital printing equipment can vary widely. (Note: Some manufacturers offer leasing programs for digital printing equipment.) To give you a general idea, here are some base prices from some of the manufacturers contacted for this article:
• $13,995: 30"roll-fed printer/cutter, four-color, eco solvent
• $16,995: 64" roll-fed, four-color, eco solvent
• $19,995: 12" x 11" flatbed, six-color, UV
• $29,995: 20" x 13" flatbed, six-color, UV
• $29,995: 64"roll-fed printer/cutter, nine-color, eco solvent
• $32,500: 10" x 24" flatbed, eight-color, UV
• $35,495: 64"roll-fed, eight-color, eco solvent
• $55,995: 104" roll-fed, six-color, eco solvent
• $68,995: 64" hybrid, six-color, UV
Conclusion
    Digital printing is somewhat of a new process to our industry but it is clearly one that is here to stay and that has a great deal of potential. First and foremost, digital printing is a full-color process and that carries a lot of weight in the personalization industry. Consumers clamor for products featuring full-color photos, graphics, logos and artwork, and these printers can do this type of work quickly and easily.
    Secondly, the process is pretty versatile which gives you the opportunity to tap into some new markets that you may not have thought of. With a roll-fed printer, for example, you can sell banners, signs, wall art, even vehicle graphics. And the flatbed printers give you even more opportunities for printing on a wide variety of substrates and items.
    If you haven’t considered digital inkjet printing for your business, perhaps you should. It could mean one more step in the direction of diversification.

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