By Olivia Cahoon
Coatings enhance the appearance and durability of printed products, increasing the printed product’s value. Spot or flood coatings and varnishes in either UV or aqueous formulations are available. UV coating is popular for digital applications and recommended for paper products with full-coverage images like book covers, cards, and posters. Aqueous coatings offer fast drying capabilities and typically don’t require a heat lamp. These coatings are generally used to protect against blemishes, scratches, and smudges.
Here, we discuss considerations and challenges for coating digitally printed output in digital production environments, including method and the best equipment configuration.
Above: Steinemann continually develops its full flood and spot varnishing machines.
Coatings give digitally printed products added effects that range from matte to high gloss. Effects like high gloss help improve ink adhesion and overall print quality while matte and soft touch provides tactile appeal. This variety gives print providers the ability to meet an array of client demands.
Flood and spot coating capabilities ensure the market provides options for every digital need. Spot coating offers raised texture for physical touchpoints while flood coating covers the entire sheet to protect printed media and enhance colors.
Max Allen, dealer manager, Graphic Whizard, says advantages for coating digitally printed output include protecting toner on printed pieces, enhanced color, vibrancy, and water resistance.
To get the most from digitally coated pieces, Albert. J. Nuño, director of sales, Latin America, senior advisor coating solutions, Brandtjen & Kluge, Inc., says print providers should consider suppliers that handle a range of coatings like gloss, matte, and satin. “With digitally printed sheets you may have to have various suppliers for different applications,” he offers.
The range of coating options available bring benefits and challenges, which depend on coating type and method. According to Anthony Gandara, product manager, Duplo USA, raised UV spot coating is primarily used to highlight an image or text by applying varnish to a specified area. “Print providers can create and add their own embellishments to enhance the appeal and value of their products,” he says.
Challenges result from the chemistry between different types of coatings and inks. According to Gandara, compatibility between toners, oils, and paper helps avoid adhesion and coating issues.
Some digital inks are challenging for coatings to adhere to. Danielle Wood, marketing specialist, Harris & Bruno, says adhesion difficulty can be overcome by using a coater with various heat settings and working with coating suppliers.
She says Corona treatment is an alternative method for addressing adhesion issues. The process alters the surface energy of printed pieces with digital inks to allow adhesion. The treatment is used for plastic films and metallic foils and is applied before printing, laminating, or coating.
Heavily handled applications are ideal candidates for coating treatments that add durability. Coatings provide protection with low-rub characteristics and are used for direct mail, folding carton, and packaging applications.
According to Nuño, digitally printed pieces handled in outdoor environments or those that come into contact with water are well served with a coating. “UV coating is the best product for these types of environments with scruff resistant, smooth layer, and solid adhesion properties,” he explains.
Allen believes any digitally printed piece handled regularly is well suited for coatings, especially business cards. He says a business card with a coating will stay in your pocket the way it was printed until you have a chance to hand it out.
Digitally printed direct mail benefits greatly from coating, which act to protect soft digital inks that scratch easily during handling. According to Wood, one quick pass through a digital coater puts a protective coating over any digital print to ensure it arrives in the customer’s hands looking as it did when mailed. “A coating creates the look and feel of offset printing and can be the finishing element that really catches the eye of the consumer on a printed piece,” she offers.
Other popular coated applications include beverages and containers, commercial printing, corrugated, flexible packaging, food service, and labels.
When looking to invest in a coater for digitally printed output, print providers must consider print applications, coating types, and the printers they use. Determine the proper coating solution based on application requirements like whether brighter colors or durability are more important. In addition, consider if the coating encounters food, which would require a non-toxic, food-safe solution. Once the print provider understands the end goal, it can determine compatible coatings.
For printing environments with multiple coating chemistries, Wood says it’s machines should support changeover to provide easy setup, washup, and minimal downtime. Additionally, automation, reliability, and high throughput are important—requiring the proper equipment and features for each coating type. “While a roll coater may handle simpler coatings well, a chamber/anilox system should be considered if a print provider is looking to use difficult-to-manage coatings with particulates,” she explains.
General considerations for coating equipment include sheet size, coating type, and run length. Roller coaters are suitable for high-quality finishes like high gloss UV, matte, soft touch, and pearlescent coatings. Some machines offer features for easily changing coatings, preventing smearing, and warming varnishes.
For UV spot varnishing, Ludwig W. Allgoewer, head of print enhancement, Steinemann Technology, says printers need an electronic registry for sheet-to-sheet correction at all times. He believes only coating machines with digital applied varnish offer this feature.
Additionally, prints from digital presses need a thin full-flood varnish before applying a UV spot varnish. “UV spot applications need an evenly closed surface to achieve good results with spot varnish, which makes proper full-flood pre-coating after printing a need in most cases,” explains Allgoewer.
As print, media, and priming solutions continue to advance, drivers for coating digitally printed output remain consistent. “We work in a competitive environment focused on creating value and increasing profit for printers,” says Wood. She believes technology’s advancing speed and the industry’s competitive nature keep high-quality coating in demand.
Allen agrees, adding that the drive for coatings hasn’t changed. This is a result of customers demanding professionally finished pieces for a low cost while printers seek ways to stand out and offer more to their customers—using digital coatings as a means for value-added effects.
According to Michael Barisonek, VP, sales and marketing, Epic Products International Corp., coating has always been a standard in offset, which in turn has affected digital. “Because of this, digital output protection will continue to be a requirement as printing and substrate advances address ink adhesion, not durability of the ink, after printing,” he says.
Nuño agrees and believes the demand for UV and aqueous coatings is growing. “With the on demand need that printers face, the protection and enhanced look coatings offer is still far better than what a digital press offers,” he adds.
Specialty trends like soft touch coatings gain popularity as clients demand quality features. According to Wood, these coatings provide the visual and tactile appeal that determines if a customer selects a package or mail marketing piece.
Soft touch coatings are a mix between matte and satin, giving the paper a velvet feeling that is fingerprint resistant. It can be applied inline during the printing process for fast drying or applied as an inline UV coating. It also protects against scruffs and smudges during finishing operations.
Soft touch coatings are an eco-friendly solution that is non-yellowing with an added gentle touch. It is used for book covers, business cards, brochures, catalogs, mailers, pamphlets, as well as postcards.
Nuño notices soft feel and soft touch coatings trending in the digital space. However, he warns that soft coating types can be challenging to apply with roller coaters.
The choice between nearline/offline or inline coating solutions is determined based upon application, job length, and coating types. Each type has its own benefits and several devices available for either setup.
As a touch-free method, inline coating is beneficial for reducing labor by using a minimal number of employees to run the press in one pass. Inline coaters also reduce waste, a benefit that appeals to print providers of all sizes. Printed sheets are directly loaded into the feed tray—unlike offline coaters—and have features for two-way communication.
According to Wood, inline and nearline machines reduce the time to print and coat. She says offline machines should be considered when a printer has multiple print engines. “With this type of solution, the machine is available to be used for various applications and print devices, whether conventional or digital,” explains Wood. Offline solutions allow page priming and coating while maintenance is performed. However, if an inline machine’s workflow requires maintenance, the entire system is down.
Those with multiple print engines or longer runs typically choose nearline/offline solutions—especially with the use of multiple coating types. Offline solutions are accompanied with high-capacity stackers and feeders and chamber/anilox systems.
Using an automated UV coater, Allen says offline finishing has no limitation to the print engines being used. On the other hand, inline solutions mean only one engine can feed the machine.
Before selecting an inline or nearline/offline solution, Nuño suggests print providers consider how many presses require the sheets to be coated. “If you go inline, then you are limiting the use of that coater to that press—forcing your shop to get more coaters to accommodate other presses. However, inline increases productivity for any one press,” he explains.
The price differences between inline and nearline/offline solutions is generally application dependent. To get the best comparison between the two types of equipment, print providers should consider features and service costs that may be added or required to operate digital coaters. “Generally, a solution with a separate feeding system will be more expensive than adding a conveyor to connect another machine,” explains Allen.
Gandara warns there is almost always a service cost required for inline operation, however, finance options may be more easily acquired.
Andy Brannon, national sales director, American Ultraviolet Coating (AUV), points out that inline coater solutions have a large footprint and price tag. “The large print providers with major output have put considerable capital into inline coating solutions,” he explains.
However, Wood believes inline typically costs less because nearline/offline digital coaters require additional features to purchase. Optional features can be used to automate priming, stacking, and feeding.
According to Nuño, the price difference between nearline/offline digital coaters to inline isn’t very different. He believes savings is only apparent when print providers go offline without a feeder and feed by hand. “Many shops start off this way. Handfeeding can yield up to 2,000 sheets per hour (sph),” he shares.
Here are product highlights from coaters serving digital print environments.
Alliance Technology Corporation (ATC)’s UV-36SD Cyclone is an offline, sheet-fed liquid coating system for protecting and enhancing output materials from digital and photo printers, featuring a coating width of 36 inches and thickness up to one inch. ATC also offers its UV13 Cyclone offline with a coating width of 13 inches and thickness up to .75 inches.
AUV digital coating systems handle a maximum width of 52 inches or any length when fed by hand. The AUV systems handle roller coater and peristaltic pump compatible coatings. “We have provided our systems to all sizes of print providers, even some that have an inline solution per their production needs,” shares Brannon.
AUV engineers and manufactures nearline/offline UV and aqueous roll coater systems. The systems can be palletized with AUV universal feeder and stacker lines.
The company also offers the Linear Measurement System (LMS) for print providers that need coating on digital output and non-paper substrates. The LMS determines exact digital calibration to change between thin and thicker substrates including non-paper substrates.
Brandtjen & Kluge offers inline and nearline/offline equipment. “Customers choose how they want their setup and we make the recommendation based on their needs,” says Nuño. Its coaters are made for a variety of applications including cardboard, paper, plastic, and wood.
Released in July 2017, the Brandtjen & Kluge OmniCoat 1800S and 3000S Servo are compatible with gloss, matte, primer, satin, and soft touch coatings. The coaters feature a user-friendly touchscreen panel and precision self-roller adjusting. It is equipped with an AutoFeeder and Stacker and runs 5,000 sph.
Nuño says the coating devices are memory capable and feature lower power consumption as well as fast and easy cleanup. OmniCoat has less than a five minute startup and five minute cleanup with gloss coating. Matte, satin, and aqueous coatings entail 15 to 30 minute cleanups. The 1800S is $40,000 and the 3000S is $50,000.
Duplo offers offline solutions for UV flood and spot coating. Released earlier this year, the DDC-810 Raised UV Spot Coater includes 600×600 dpi inkjet heads and handles a maximum paper size of 14×29 inches. It features adjustable varnish thickness from 20 to 80 microns in addition to an air suction feed system with almost six-inch feed capacity. The coater processes up to 36 pages per minute (ppm) in letter size and 21 ppm in ledger.
Job preparation is easy with the PC Controller, which is included with the DDC-810, says Gandara. “Using the PC Controller software on the DDC-810, operators can set up a job in four steps and begin production in minutes,” he explains.
The DDC-810 is compatible with coating types from HP, Xerox, and offset solutions. While still under development, Gandara says laminated media from Canon, Konica Minolta, and Ricoh are also compatible.
The coater’s CCD camera system automatically corrects for shrinkage, stretch, and skew. Unique registration marks allow precise alignment of the spot UV layer onto the printed document. The DDC-810 coater is $160,000 with a preventative maintenance agreement.
EMT International offers the Chameleon Coater, which is available in its UVF20, UVF30, and UVF42 models for 20-, 30-, and 42-inch web width applications, respectively. The device operates in simplex or duplex capability with a standard speed of up to 500 feet per minute (fpm)—higher speed options are available. It features inline or near-line UV coating with an aqueous coating option available.
Epic Products offers inline and nearline solutions and configures coating systems according to customers’ needs and requirements. Its newest coating system—the Epic CT-750—is an integrated sheetfed coater for B2 formats.
The Epic CT-750 applies spot coating in UV, aqueous, or specialty coatings like blister or soft touch. It feeds 29.5-inch sheet sizes and offers glue tab and knock out capabilities. According to Barisonek, it can run inline with presses of this size or offline with a feeder.
Epic also offers the Web Coating System for duplex coating with inkjet and digital webs. UV and aqueous coatings are supported with 20-, 30-, and 40-inch widths up to 1,000 fpm. “Epic Products has a list of suggested UV and aqueous formulations tested with various stocks and printing methods, and we offer testing services to customers and printers considering Epic coating systems,” shares Barisonek.
GMP offers its SureCoater Series for print on demand environments. Ideal for a range of applications it features an ergonomic touchscreen for easier operator control. The series offers adjustable UV intensity, precise coating thickness adjustment, and a compact design, gloss and matte coating, and an automatic UV recirculation pumping system.
Graphic Whizard’s UV coaters are offline systems and can be run inline with finishing equipment to automate and remove touch points. According to Allen, Graphic Whizard partners with Actega and Kelstar for coating and recommends them to customers. “The samples we run in house are all from Actega,” he adds.
Actega offers water- and UV-based overprint varnishes and coatings including rigid metal coatings for food cans and protective coatings for flexible packaging.
Graphic Whizard’s VividCoater XDC 370M is a digital coating system that handles multiple coating types. It is a 14.5-inch wide, full-flood machine with touchscreen controls, removable roller, and three IR lamps with adjustable intensity.
The coater can be used as an inline installation to any digital print engine or inline Graphic Whizard creasing and feeding device. The XDC 370M features a three-pump coating system.
Harris & Bruno offers inline and nearline/offline coating solutions for a variety of machines and applications. “We provide solutions for both large commercial print environments and smaller print environments, and as a result, our machines may see many different applications,” says Wood.
Released in September 2017, the ExcelCoat ZRS30 Spot Coater is compatible with all types of UV and aqueous coatings including glitter, gloss, high gloss, matte, pearlescent, soft touch, and specialty coatings. It handles inline and offline spot or flood coating and has a 29.5-inch coating width. The ZRS30 utilizes a camera registration system to compensate for digital drift.
“High throughput and increased efficiency make it ideal for packaging and commercial print applications,” offers Wood. The ZRS30 is priced between $50,000 and over $300,000 depending on features and applications.
Kompac provides a variety of coating solutions, including its ELITE line for labels, EZ Koat for flood coating, and Kwik Finish products for spot coating.
MGI offers its JETvarnish 3D products for spot coating effects. The company’s JETvarnish 3D Evolution is a B1+ format device specially designed to offer digital and offset printers a scalable upgrade path for a full range of production environments and postpress applications.
Print enhancement machine provider, Scodix, offers the Scodix Ultra Digital Press and the Scodix Ultra Pro, which enable specialty coating. Additionally, the company’s S-Series allows print providers to add tangible dimensions that stand out.
Shark Machinery presents several coating solutions, including its latest SUV-24 PLUS UV Coater, which offers a “glass like” finish, according to the company. Similar to its other coaters, the machine coats using traditional UV coating liquid, but also has the ability to offer a soft touch and glass shine effect. The machine offers a maximum width of 25.25 inches and is compatible with both offset and digitally printed stocks.
Steinemann Colibri systems are used for full flood coating of digitally printed products in commercial applications. The Colibiri line may be operated for UV varnish, aqueous, or hybrid coatings and suits a variety of applications including matte and soft-touch varnishes.
Colibri systems handle 12,000 sph and are compatible with a range of substrates including adhesive labels, cardboard, magnetic, paper, and plastic. Smith says the systems can be alternatively equipped with a roller coater for full flood varnishing or an Anilox roller.
The company also features its dmax digital inkjet systems for spot and relief varnishing. Featuring performance of up to 10,000 sph, the machine offers minimal setup times and high substrate flexibility.
TEC Lighting’s TruCoat UV Coater features an easy-to-use touchscreen, variable intensity IR lamps, and quick-change rollers that take only five minutes to replace, according to the company.
Targeting digitally printed folding cartons, TRESU DigitalSolutions provides coating technology for an efficient, single-pass digital folding carton workflow. TRESU’s modular coating systems apply full-surface, spot, and line varnishes inline with the latest digital printing presses from leading OEMs. They work with a range of UV-curable and water-based coating media, to create gloss, matte, soft touch, and metallic effects. These are specially formulated by TRESU to perform in the unique conditions of the digital line.
A range of features and capabilities differentiate digital coaters from one another in addition to compatible coating types and configurations. Print providers offer coating for digitally printed output to add vibrancy and durability to a range of applications from business cards and book covers to labels and packaging. With demands for stronger durability and special effects, the coating landscape continues to expand for on demand and high-volume production environments.
Nov/Dec 2017, DPS Magazine