In many cases, a coating is the final touch on a printed piece. Not only is it that lasting effect that really makes the colours “pop,” but it also has added value in protecting the document. Coatings can keep fingerprints, scratches and scuffs at bay, while adding a glossy finish that creates depth to the piece and draws the reader’s eye. There are different types of coating for different applications, including varnish, UV coating, and aqueous coating. Lamination is also an option, but that’s another story for another day.
A number of big offset presses have coating capabilities already included via an extra printing unit. Instead, let’s take a look at some interesting developments in coating equipment and technology for offline and digitally integrated products!
Graphic Whizard VividCoater
Graphic Whizard is a company known for its coating products. Its VividCoater line are low-maintenance machines that take up a small footprint, while delivering impressive quality and versatility. Great for the on-demand print market, vibrant effects can be created with a low cost per page.
The XDC-Micro model has a footprint less than 3’x3′ and can produce speeds up to 2,700 sheets per hour. It can achieve different kinds of coating patterns, even one with a raised snakeskin-like effect. Graphic Whizard also has spot coating devices in its VividCoater family of products, such as the DLG model.
Kompac Kwik Finish
Kompac has been providing coating, drying and dampening systems to the industry for over 30 years. The Kwik Finish is an offline coating and curing system that can apply UV, aqueous and other specialty coatings to a wide variety of paper and plastics. Both spot and flood coating is possible at speeds of 5,500 sheets per hour. The company says the system is capable of five-minute coating change and clean-up.
From Kompac: “From onion skin to plastics; whether digital output or offset, each job will have the visual appeal, lasting durability, protection and rub resistant finish that your customers expect.”
The JETvarnish from MGI is a pioneering device – it is the first digital spot UV coater with a 20″ × 29″ format. Capable of producing both flood and spot coating, the award-winning product also does the digital printing as well, making VDP a possibility.
The JETvarnish has integrated UV coating that dries sheets “on the fly” via a conveyor belt. The fact that no ozone or solvents are required makes it an eco-friendly option. Sheets are fully dry and can be handled immediately. Satin, gloss and ultragloss finishes are possible. Designed for short, medium, and even long runs, the product reportedly has a fast startup and utilizes no plates, screens or waste. MGI says production speeds are up to half a meter per second, and the first page is out in 16 seconds – no pre-heating is necessary. It can accommodate a wide range of substrates including sheet widths from 8″ to 20″ and weights from 50 to 220 pounds.
Drytac VersaCoater XL
This device from Drytac can coat at sizes up to about 80 inches wide, perfect for posters or POP displays. This is a UV coater that doesn’t emit any VOCs. The machine has flexibility, allowing users to adjust coating thickness from two to more than 20 microns. Variable roller speed allows for textures from fine to heavy.
The VersaCoater XL can handle rigid cut sheets up to three inches thick, as well as flexible and roll-to-roll media. Speeds from 20-110 feet per minute can be achieved. The device is designed for applications such as indoor graphics and signage.
How a printed job dries is an essential factor in the quality of how it turns out. If sheets aren’t given long enough to dry, a multitude of problems can occur such as rubbing, sticking, smudging, and so on. Manufacturers have developed a number of in-line solutions to combat the effects of this problem from heat lamps to blowers to spray powder.
There are a whole gamut of factors that go into quick drying time including the choice of paper and ink, and even the press itself. Let’s take a look at products from all of these areas and see how they work to achieve optimal drying time.
Quick drying printer – Agfa :Jeti 3348 TurbTech System
Agfa has recently launched its :Jeti 3348 printer, which is considered to be the fastest 3.25m grand-format printer on the market today. The HSS in its name stands for high-speed solvent, and the device uses a new TurbTech drying technology.
TurbTech combines traditional mesh back heaters with a front drying system that uses non-laminar warm air flow drying technology. This lowers vapour pressures and delivers high speed drying without overheating. Because of the :Jeti’s TurbTech system, the printer can deliver 2,500 sq. ft/hour speeds. The 48 Spectra print heads also play an important role in creating such high speeds, as the printer’s motor moves them at speeds up to two metres per second.
Quick drying quality control – Heidleberg DryingMonitor
Not long ago, Heidelberg added DryingMonitor to its line of Star peripherals. It is considered a “world first” and has innovative sensor technology and in-line measuring tools that tell press operators whether a sheet is really dry or not.
How does it work? Heidelberg says it best: “The system records all of the relevant air volumes and temperatures in the drying process together with the air humidity and the water content of the coating applied and uses the data to determine the drying quality.” This in-depth monitoring ensures that problems such as yellowing and sheets sticking don’t occur. Printers who use this technology (available for the Speedmaster XL 105) can achieve better control over the drying process. This, in turn, saves the company money. Dryers are a huge power drain on the overall energy consumption of a printing press, and using less power to achieve the same controlled level of dryness helps both the bottom line and the environment.
Quick drying ink – Presstek DI-Dry
Fast-drying inks also reduce the need for those energy-hungry drying units. There are a number of inks on the market that advertise their rapid-drying abilities; among them is Presstek’s DI-Dry line of waterless inks. These are designed for use on several leading press brands, including Ryobi, Heidelberg and Presstek itself.
The inks are made using a proprietary formula that contains a heavier ink pigmentation density. This means it is possible to use less ink while achieving truer colours and denser solids, which leads to a faster drying time and getting “more miles per gallon,” as they say.
As a side note to this Presstek ink: it is made with more than 50 percent renewable content (bio-derived raw materials), so it fits in with the environmental commitments that many printers are making today.
Just be sure to do your research before selecting one of the many fast-drying inks for your shop. Sometimes there’s a trade-off involved, meaning they may dry faster but other qualities like rub resistance and gloss may be lacking.
Quick drying paper – Sappi Tempo
Let’s also take a look at papers designed to dry faster. Sappi has a brand of paper called Tempo that, due to its innovative coating, has uniquely fast ink setting and drying properties. The company says it also has superior ink scuff resistance and needs less anti offset powder.
Tempo is a coated, wood-free sheetfed product that is FSC and PEFC certified.
According to Sappi, it is a silk paper that behaves like a gloss. Papers like this one that dry at quicker rates can be converted much faster, without needing protective over-coating. From Sappi: “Due to its unique properties, Tempo is helping the environment. Less chemicals are used, fewer washing stops, less use of water, less anti-setoff powder…and, energy is saved thanks to the reduced drying time.”