P&P: Why not?

RH: Cost. Only when - or if -DTG can match screen printing in speed and price will it break out of the niche market it now occupies. At present, automatic screen printing presses turn out garments in a fraction of the time it takes to digitally print the same design. In addition, the per-print cost of screen ink remains far less than digital printer ink. And, for now, screen printing is the only realistic option for garments requiring specialty inks and for custom applications like beads, rhinestones, foil and flock.

P&P: Do you see the day when digital garment printing will be able to do all that?

RH: The world we live in is full of things that few, if any, envisioned, so I'm hesitant to say it will never happen. However, if it does, it's unlikely to be in my lifetime.

P&P: You said digital garment printing occupies a niche market...

RH: DTG is ideal for short runs and one-offs [prints characterised by a slight change - like a name or number - from one print to the next].

P&P: Given its relatively slow print speed and high ink cost, what makes DTG more appropriate for this type of printing?

RH: Set-up. The cost of colour separation; screen coating and exposure; and set-up and registration represents a significant expense. That's especially true when intricate designs and multiple colours are involved. And that's why there's such a huge economy of scale involved. If a print run is large enough, the set-up costs become nearly inconsequential, but they're enough to stop a short run dead in its tracks. DTG printing, while more expensive than mass-produced screen-printed images, brings the cost of short runs within the reach of most customers. With minimal set-up costs - meaning no screens to prepare, no screen registration, and no setup or teardown - garments can be profitably printed in the smallest quantities.

P&P: What is required to set up a digital print run?

RH: Nothing more than a digital-image file. The operator simply pulls up the image, specifies the number of prints, and sends it to the digital printer. While the last - or only - garment using that file is being printed, the operator can pull up the file for the next garment.

P&P: What's the target market for digital printers?

RH:  While we're seeing some larger companies investing in multiple DTG printers, the greatest demand is likely to be from embroiderers and screen printers since they're well positioned to serve the pent-up demand for small custom orders. In addition, embroiderers who may have been interested in expanding into screen printing, but were dissuaded by start-up costs; space requirements; or an additional learning curve are likely to find DTG particularly attractive.

P&P: Do you see any other opportunities being opened by digital textile printers?

RH: Actually, the possibilities seem nearly endless. We typically think of DTG printers going to companies that are already involved in the decorative apparel business. However, the fact that these printers take up little space and require far less expertise than screen printing means that companies in wholly-unrelated fields will consider them. Just as affordably-priced, high-definition camcorders make it easy to try your hand as a film director, DTG printers make it easier to become an apparel decorator.

P&P: Can you give us an example of DTG printing by someone in an unrelated field?

RH: Sure. Take a company that specialises in cycling tours of Cornwall. On the first day of the tour, the company takes a group photo of the participants and has shirts ready by the end of the tour, or even the end of the day. The vendor could also incorporate participant names; the date of the tour; and/or a map of the route travelled with notations about things done or seen on this particular outing. In one-off fashion, each shirt could include the name of the participant it was to be given to. That would be far more memorable, and desirable, than a generic tour design. That's just one example, but I'm sure we'll see applications most of us haven't considered. And the Internet is already spurring significant growth.

P&P: Besides relatively high ink costs and print speeds, are there any issues with DTG printing?

RH: No technology is perfect, and digital garment printing is no exception. At present, some of the key issues involve pre-treatment, white-ink formulas, computer hardware and software, and printer maintenance. The issue with pre-treatment is that all dark-coloured garments must be sprayed with a pre-treatment solution prior to the application of the white-ink base upon which the image will be printed. Unfortunately, most pre-treatment is done with a hand-held paint sprayer, making it difficult to evenly apply the proper amount.

P&P: What happens if the application is uneven or the amount is inadequate?

RH:  As you know, ink bonds instantly with pre-treatment chemicals. The speed of that chemical reaction keeps the white ink on the garment's surface, creating a base layer for the other colours. Apply too little pre-treatment, and the result is poor print quality. Apply too much, and the image will wash out when the garment is cleaned. If pre-treatment is applied unevenly, parts of the image may be perfect, but other areas may have poor print quality or wash out prematurely. In short, the amount of pre-treatment and the evenness of its application have to be spot on. That's why we're developing a machine to evenly apply the precise amount of the pre-treatment chemical.

P&P: And the white-ink formulas?

RH: White inks have dramatically improved, but printhead clogging is still an issue. White inks are heavier than coloured inks, and a tremendous amount is needed for printing dark garments. Unfortunately, titanium dioxide, an abrasive solid present in white ink is prone to separate from the other components in white ink. In addition, the size of the titanium dioxide particles creates printhead-clogging issues. Whether the ink comes in a cartridge or in a bulk system, it needs to be agitated at least once a day to blend the solids back into the liquid.

P&P: But as long as you agitate the ink containers at least once a day, you shouldn't have clogging problems?

RH: No. That's only part of the solution. Because printheads can dry out, most machines need to print at least several hours a day. Since we know that's not always practical, especially for shops that don't operate seven days a week, we developed a program to run a nozzle check at preset intervals when the printer isn't in use. The effect of periodically running a small amount of ink through the printheads on a regular basis dramatically reduces the chances of clogging.

P&P: What are the issues with hardware and software?

RH: Most DTG printers are sold without a computer. That gives some manufactures a competitive price advantage by reducing the price of the system. However, that also means that there's no standardisation in a key system component. As most of us know from personal experience, working with a company's tech support unit to troubleshoot a balky computer can be a nightmare - and that's with technicians trained to handle a specific line of computers. If customers provide their own computers, there's no end to the hardware and software conflicts that may ensue. That, plus the fact that most PCs, even fairly recent models, are ill equipped to support a DTG printer led us to make the tough decision to include a PC in our digital-printer system. We decided the slight additional cost was well worth the reduction in system problems and the increase in customer satisfaction.

P&P:What's the issue with maintenance?

RH: As a group, DTG printers require more maintenance than screen-printing presses, and the sooner printers accept this fact, the better. Basic knowledge of how to maintain the digital printheads and the supporting items that feed ink is a necessity.

P&P: What's changed since DTG printing burst onto the scene?

RH: Although it's not a technological advance, the increased competition has helped improve quality and kept pressure on printer prices. That's good for customers and good for manufacturers up to the task.

P&P: What about technological advances? Have print speeds got faster?

RH: Speed has increased, but it's unlikely to increase much more under the constraints of current technology. The next big step in print speed will likely come with the arrival of affordable and reliable fixed-array printheads.

P&P: For those who aren't familiar with fixed-array printheads...?

RH:  A conventional inkjet printhead - like those used in DTG printing - involves a series of stops and starts, with the printhead moving back and forth across the width of the substrate as the substrate passes below. The substrate has to come to a stop while the printhead makes a pass; then the printhead pauses while the substrate is moved and the process is repeated. In contrast, there are far more individual printheads on a typical fixed-array. In fact, there are normally enough printheads to span the entire width of the printer. Since there's no back-and-forth movement of the printhead, print speed is dramatically increased. Some manufacturers claim fixed-array print speeds in excess of 50 colour pages per minute. With fewer moving parts, operating costs may also decrease. Unfortunately, the high cost of fixed-array printheads makes them impractical for DTG printing for the time being, and even when that changes, fixed-arrays will be more expensive to replace.

P&P: Any other advances?

RH: RIP software has improved, at least among some manufacturers new to the market. Many, if not most, printers don't realise the role RIP software plays. Well-designed RIP software will quickly convert data files into printed images with maximum sharpness and exceptional colour accuracy while minimising print time. In addition, our i-Colour RIP software precisely calculates the need for white underbase when printing on black garments. Since i-Color RIP recognises black areas in the image file, it prevents the printheads from laying down a base of white in those areas and then printing over the white with black ink. This can substantially reduce the consumption of white and black ink, significantly increase print speed; and provide superior shading and gradations.

We've also made advances in transporting and registering garments. Although inkjet print engines have built-in encoders and transport motors, they're designed for moving sheets of paper one at a time, and no provision is made for the precise repositioning necessary for double-printed designs on dark shirts. When used to drive the relatively heavy weight of a pallet and shirt, these encoders are unable to maintain pinpoint accuracy, and the overworked motors are vulnerable to early failure. So, rather than relying on the print engine's built-in low-resolution encoder, we developed Absolute Position® Technology, which enables us to print multiple layers of ink on dark and colour shirts with consistent layer-to-layer accuracy.

P&P: Most conventional conveyor dryers are too short to cure digitally-printed garments in a single pass, and heat presses, while effective, are labour intensive. Have there been any advances in this area?

RH: Heat presses are still the best solution for smaller operations. As you pointed out, they're effective. They're also compact and relatively inexpensive. However, they're not a viable solution for high-volume digital operations. To address that need, we recently developed the Boomerang Gas Dryer. Although it can also function as a traditional one-way gas dryer, it has a second belt that moves in the opposite direction. Digitally-printed garments are automatically dropped onto the lower belt, giving them twice as much time in the heat chamber and returning them to the operator.

P&P: One final question: You were somewhat late entering the market. Why was that?

RH: It's a combination of things, most of which were positive. First, it's no secret that rushing to market isn't necessarily the best way to create a reliable product. Early adopters of any technology often find that they've paid more and got less than if they'd waited even a short while for competition to develop and problems to be identified and sorted out.

In addition, the last few years have brought record sales to our textile screen-printing division, and it only made sense that our first priority remain the satisfaction of customers in that market. We've also been heavily invested in aggressively expanding our worldwide presence.

However, while all that was going on, our engineers continued to work diligently to develop an affordable DTG printer capable of producing exceptional images, and one without some of the problems found in many of the models that were first into the market. We think we've done that, but the final verdict rests in the hands of the customer.

Rich Hoffman is president and CEO of M&R, the Chicago-area company he co-founded in 1985. M&R manufactures textile, graphic, and digital equipment. Go to: http://www.mrprint.com/ for details

Printer friendly version

Email this article to a friend

Bookmark this

---