By Melissa Donovan
Digital single-pass printing is a revolutionary concept, as implied from the name—a print in one pass. To achieve this, machines must be equipped with upwards of a hundred printheads. As technology has evolved throughout the last 20 years, printhead performance has advanced tangentially—creating a powerhouse of speed combined with high-quality imagery.
Single-pass printing is found in corrugated and ceramic markets as well as textiles. “Single pass represents an innovation in digital textile printing, even if it is a simple concept. The idea is the same as traditional rotary textile printing—a fixed array of printheads, arranged in bars one for each color, while the fabric runs below them, applied on sticky conveyor belts,” explains Dario Bernasconi, technical sales engineer, MS Printing Solutions.
Textile manufacturers recognize the advantages of working with digital as a decoration method. It’s eco-friendly, offers high levels of productivity, and meets the current demand for shorter turnaround times in addition to the feasible production of smaller runs of limited designs.
History of Single Pass
Single-pass printing in the textile segment is the most recent iteration of this technology. Many printer manufacturers participating in this space also hold patents related to single-pass devices used in ceramic and corrugated.
For example, EFI leveraged its Cretaprint ceramic tile product line as well as its Nozomi single-pass corrugated printer technology and subsequent Cubik single-pass printers used in the building materials market in the construction of its textile printer. “EFI Reggiani engineers and experts collaborated with our EFI colleagues in Spain, along with EFI Fiery experts, to develop the EFI Reggiani BOLT, which is manufactured in the EFI Reggiani facility in Bergamo, Italy, near Milan,” notes Micol Gamba, product marketing manager, EFI Reggiani.
Similarly, KERAjet’s experience in developing single-pass printers for the textile sector derived from its work creating printers for ceramics. “KERAjet installed its first single-pass printer in 2018 in Mexico for the decoration of blankets, and has since started other projects in the fashion, home textile, and carpet industries. Whether for flat fabrics, knitted fabrics, or fabric with high fiber thickness,” explains Juan Montero, textile sales manager, KERAjet.
Each company’s history tracks a bit differently. MS Printing Solutions began research and development (R&D) on single-pass printers at the end of the 1990s. Bernasconi says the company built a prototype in 2002—with the first speeds clocking in at 26 meters per minute (mpm).
“Thanks to the rapid industrial printheads’ performance evolution, MS Printing Solutions installed, in Italy, the first functioning LaRio single-pass machine in 2011. We haven’t stopped since. By the end of 2012, five LaRio machines were functioning worldwide. Today, 32 LaRio printing machines are working worldwide using reactive, disperse, dye-sublimation, and pigment inks. The printing speed reachable today is 120 mpm and the printing width is up to 3.2 meters,” says Bernasconi.
Preferred Over Analog?
Traditional production printing of textiles involves rotaries, screens, time, limitations in color, and minimum number of quantity requirements to be met. It’s no surprise that single-pass textile printing—with similarities in the process—takes the positives of analog and presents its own advantages, thus developing a steady presence in textile production worldwide.
While “analog printing technique remains the best in terms of print quality and achievable effect, single-pass digital textile technology gives much for flexibility, and of course it has a huge advantage from the environmental point of view,” shares Gianluca Macchi, manager of sales – inkjet textile, Konica Minolta Business Solutions Italia SpA.
Screens must be engraved, inventoried, and washed, which Toff Shen, marketing manager, Atexco, notes is a long procedure and creates more pollution. “Furthermore, analog limits colorways and it cannot make halftone designs. There is also a minimum quantity requirement. While digital single-pass printing can solve all the above problems.”
And how? According to Bernasconi, a digital printer takes up less footprint since it does not require rotary or flatbed screens, which not only reduces process steps but minimizes inventory space used to house the screens.
“In digital printing, the water consumption is 60 percent less, and the energy consumption is 30 percent less. Color management is through software, thus using only the ink quantity necessary to achieve colors and designs. The ink wastage is reduced by 20 percent. The fabric’s wastage during the design or colorways change is nearly null,” continues Bernasconi.
Focusing on the creative side of design and product development, Montero points out advantages like “the ability to obtain high-quality graphic details, less limitations in size, almost infinite flexibility in the development of new products allowing high customization, shorter development time of new products, and lower costs as you don’t need engrave rollers and screens.”
“Digital printing allows for the potential production of infinity colorways and designs. There is no limit to the number of colors printed. Thus, expanding the designers’ creativity at low costs as well as granting a lean workflow,” says Bernasconi.
Macchi agrees, citing single-pass technology as the ideal substitute for traditional rotary printing. “The great advantage of digital is the fact that no more huge batches are needed in order to make the business feasible and attractive.”
It is important to point out that digital single-pass printing is not necessarily a one-to-one replacement solution to an analog production line. While textile manufacturers are attracted to the technology, there are a “range of applications—such as metallic ink—that cannot be accomplished by industrial digital textile printing,” explains Gamba.
Digital printing, as aforementioned, is attractive for numerous reasons. Multi-pass or scanning technology is also used in textile decoration, however for high-production environments, single-pass printing is preferred due to its ability to reach high speeds.
“The main difference between scanning technology is the fact that with single pass the number of printheads is much higher, which allows production to achieve incredible speeds that may change based on the chosen printing resolution,” admits Macchi.
Shen says that most of the digital single-pass printers available today are achieving actual printing speeds of 50 to 70 linear mph—which is similar to traditional rotary printers. This is primarily because of the larger number of printheads found on a device, as well as advancements in drive and control systems.
“Single-pass technology, more than scanning machines, makes the most out of printhead performance by offering high and constant productivity. This result is possible thanks to the advancements in printheads and inks, as the higher jetting frequency and customized ink waveform,” agrees Bernasconi.
According to Montero, multi-pass printing remains an option. “For projects where there is no requirement to produce a certain amount of meters per year, the option of a multi-pass printer is highly recommended as it allows for greater flexibility, optimizing the print quality by the number of steps and all this at a lower initial investment.”
Generally speaking, most manufacturers agree there is a minimal learning curve when transferring from traditional analog to digital single-pass printing in the textile production space. It isn’t so much operating the hardware, but more the understanding of how to properly prepare a digital file.
“The only improvement that must be done changing from analog to digital concerns the digitalization of works. The customer must know how to prepare the file and create the correct profile on the machine,” explains Macchi.
Shen agrees. “For analog background people it takes slightly more time to get into the work of single pass. The major time spent is on the operation of the RIP software and printhead maintenance.”
“While there is a learning curve for companies used to decoration with traditional systems and making the leap to digital decoration, this is short and there is also support at all stages of the project, from the operation and maintenance of the machine, to product development and issues related to color management and profiling,” admits Montero.
Textile printing benefits greatly from digital single-pass technology. Advancements in printheads, automatic maintenance and surveillance systems, drive controls, and more have taken these printers from fast to faster. Thus offering the attractive combination of speed, quality, and ability to meet demand for limited runs at a cost-effective price.
“The great advantage of single-pass printers is high productivity, as they can produce up to 60 linear mpm and even faster depending on the printer model, ink configuration, and working mode. These printers are preferred for lines producing at least four for five million meters per year, as the return on investment makes them very competitive,” concludes Montero.
Mar2022, Digital Output