A Very Brief History of Industrial Inkjet Printing
Industrial applications for inkjet are expanding rapidly – perhaps the most exciting developments in all of printing. The roots of these breakthroughs can be traced back further than you may think.
First: What makes something “industrial?” “Digital inkjet?” Or “print?”
The word “industrial” primarily denotes that which is part of a manufacturing process. While the word “digital” derives from counting with fingers or digits, it commonly refers to computer-controlled processes. I define “inkjet” as a digitally controlled process that deposits drops of ink or other material on a substrate without the print head contacting the print surface. While the word “print” derives from the Old French and Latin words for pressing, this article focuses on inkjet and inkjet-like non-contact methods for depositing inks and other materials.
(On-contact methods dominated the early days of print from Mesopotamia before 3000 BCE, where people used cylinders to roll over clay tablets to imprint seals. By about AD 200, folks in China were using woodblock to print paper and cloth. By 1040, Bi Sheng in China made movable type characters in porcelain. Metal movable type, first used in Korea around 1230, eventually appeared on the Mainz printing press of Johannes Gutenberg in about 1439. Other printing technologies arrived: etching in about 1515, mezzotint in 1642, aquatint in 1772, lithography in 1796, offset in 1875, and screen printing in about 1910.)
Sir William Thompson, later called Lord Kelvin, acquired the first patent in 1867 for a drop-deposition, inkjet-type device that recorded the Morse code signals received over the Atlantic cable. But it took almost a century for further developments to occur.
Product Marking, Carpeting, and Textiles
One of the first industrial applications for inkjet came in 1965 when Carl Hellmuth Hertz and Sven Simmonsson applied for a patent on a version of CIJ they developed at Sweden’s Lund Institute of Technology. Stork and Scitex Iris Graphics used this technology with their high-resolution CIJ technology for color photographic proofing for commercial and textile printing.
A few years later, A.B. Dick commercialized Richard G. Sweet of Stanford University’s patent (issued 1968) for continuous inkjet (CIJ) with the VideoJet 9600. Miller Brewing and others adopted it for marking and coding their beverage cans in-line with their production processes. In 1975, Milliken (Spartanburg, South Carolina) introduced the Millitron, a digitally controlled valve-air deflecting-drop CIJ printer for in-line carpet printing. The following year, J. Zimmer Maschinenbau (Klagenfurt, Austria) launched its digital valve drop-on-demand Chromo Jet carpet printer.
In the early 1990s, Seiren of Fukui, Japan, demonstrated how drop-on-demand piezo inkjet (PIJ) printers could provide custom printing of textiles used for swim and athletic wear, apparel, and automotive upholstery. Using its Viscotecs (Visual Communication Technology System) custom inkjet printing process, Seiren developed a successful business plan that provided a model for quick-response custom inkjet printing for textile industrial applications.
In the 1990s, a number of other inkjet textile printing systems proved less successful. Canon and Ichinose of Japan produced a 5.25-foot textile printer using Canon thermal inkjet (TIJ) heads and Ichinose fabric-transport and processing equipment. Encad also offered its TIJ textile printer. Both of these efforts, however, failed to gain market adoption. Italian design and print houses were seeking ways to digitally print short runs of silk fabrics for designer scarves and apparel. The first Mimaki textile printer using Epson PIJ print heads produced the high-resolution print quality that the Como Italian silk printers required. Within a few years, they were inkjet printing most of their short-run, high-value silks with Mimaki printers or Mimaki print engines atop Italian sticky-belt material-handling devices.
Inkjet Printing on Ceramic Tile
In 1998, brothers José Vicente Tomás and Rafael Vicent founded KeraJet of Almassora, Spain, to develop digital ceramic printing. Near the end of 1999, Tomás applied for a patent titled “Dispositivo que permite decorar azulejos cerámicos” for a single-pass inkjet printer for decorating ceramics tiles. In 2000, the brothers formed an alliance with ceramic material manufacturer Ferro of Mayfield Heights, Ohio, to supply ceramic inkjet ink for its project. KeraJet presented its prototype K350 (with a 13.8-inch print width), using Xaar 500 PIJ heads printing 80-picoliter drops at 180 dpi, at Cevisama, the annual international ceramics exhibition in Spain. The K350 used Ferro Quickpaint Ink.
In 2001, KeraJet began shipping its printer into the European market. In 2004, it offered the KeraJet K560 single-pass printer (with a 22-inch print width), also using Xaar 500 printheads and Ferro inks. In 2005, it launched its Titan ceramic tile printer with SII Printek PIJ heads and terminated its exclusive arrangement with Ferro for its inks.
In the following years, other companies developed, manufactured and distributed inkjet ceramic tile printers. In January of 2006, Durst (Brixen, Italy) introduced its Gamma 60 ceramic tile printer using Dimatix SL-128 AA binary PIJ heads shooting Torrecid pigmented soluble salts ink. By 2007, Xaar released its 1001 PIJ head with recirculation of ink flow through the printhead manifold, which improved head reliability with ceramic inks.
EFI has been expanding its vertically integrated offerings through acquisition of companies in industrial ceramic and textile printing. In January of 2012, it acquired Cretaprint, based in Castelló, Spain, a leading developer of inkjet printers for ceramic tile printing. EFI now offers three production ceramic tile inkjet printers with its C3, C4, and P3 models, as well as its Cretaplotter, an injection plotter for making samples and prototypes.
The market for digital ceramic printers grew quickly, capturing over 40 percent from screen printing by 2014 and now approaching 60 percent, according to the estimates of some industry observers. The economic advantages of inkjet are rapidly driving it to replace virtually all screen printing for ceramic decoration in the coming decade. Inkjet ceramic printing provides higher-resolution images that better replicate popular patterns, such as marble, granite, and wood grain, without the noticeable repeat images that characterize screen-printed ceramic tile output.
The requirements for ceramic and textile inkjet printing have inspired printhead manufacturers to develop more robust and capable heads that will likely have application for other industrial processes. Xaar’s 1001 was the first of a new generation of PIJ print heads with ink recirculation; it was later refined with the Xaar 1002 head launched in 2014. These heads have found broad application for label printing as well. Xaar also released versions of its ink-recirculation heads with larger drop volumes to meet ceramic printing requirements. It offers the Xaar 1002 in 6-, 12-, and 40-picoliter primary drop versions, with the first two capable of printing with eight gray levels (that is, seven drop sizes). Xaar also developed its 16-nozzle Xaar 001 head for printing ceramic glazes requiring drop volumes up to 200 nanoliters (1000 times the volume of a picoliter). KeraJet employs the Xaar 001 on its KeraJet K8 print station for depositing glazes as the first part of its 100-percent digital ceramic printing production line system.
Fujifilm Dimatix developed its Starfire SG1024/MC 400-dpi recirculation grayscale PIJ head for ceramic applications. Each printhead has 1024 independent channels arranged in eight rows on a single nozzle plate for single-color operation. In its 26-picoliter operating mode, it can generate drops at rates up to 35 kilohertz (or 35,000 drops per second from each of its 1024 nozzles). Its 65-picoliter primary drop system produces drops at a maximum frequency rate of 14 kilohertz. Trained users of the Starfire head can disassemble and reassemble the head’s nozzle plate for maintenance cleaning, which is particularly desirable for printheads operating in abrasive and dusty environments, such as those associated with ceramic printing. KeraJet employs the Starfire for its K6 color-decoration and decorative-effects print stations.
Other inkjet printhead manufacturers have produced robust inkjet heads to satisfy the requirements of ceramic printing. These include PIJ heads from Seiko SII Printek, Toshiba Tec, Konica Minolta, and Ricoh.
3D Inkjet Printing
3D market leaders 3D Systems and Stratasys use inkjet printing for a number of their 3D rapid-prototyping systems, and ExOne is using inkjet to form functional objects in stainless steel and also to make casting investments. Voxeljet uses inkjet printing with its binder chemistries to fabricate very large models. Both 3D Systems and Stratasys offer inkjet systems that can print z-axis layer steps that are less than 30 micrometers. Generally, this is considered the dimension below which the artifact of the step cannot be detected.
3D Systems, headquartered in Rock Hill, South Carolina, offers a wide range of 3D print technologies including a number of methods using inkjet. Its ProJet 3510 SD, 3510 HD, 3510 HDPlus, 3500 HDMax, 5000, and 5500X use Xerox T-series PIJ inkjet heads that print photopolymer UV-curable build materials. Its ProJet 3510 CP, 3510 CPX, 3510 CPXPlus, and 3500 CPXMax also inkjet print using the Xerox heads, which are able to melt wax-like build materials at 140 C for producing models for lost wax casting. Jewelers and fine metal casters are the primary markets for this device. In 2012, 3D Systems acquired Z Corp and its inkjet technology using low-cost materials and HP inkjet printheads for prototyping. It also offers non-inkjet 3D print solutions, such as stereo-lithography, which its founder Chuck Hull invented (1986 US patent), selective laser sintering, direct metal printing, and fused filament fabrication.
Stratasys merged with the Israeli company Objet and now maintains dual headquarters in Eden Prairie, Minnesota, and Rehovot, Israel. Stratasys offers PolyJet inkjet printers that produce 3D objects using Ricoh PIJ inkjet heads to print photopolymer materials with UV curing. The PolyJet printers can print a range of materials and colors. Stratasys also acquired Solidscape of Merrimack, New Hampshire, which uses its own very high-resolution (5000 x 8000 dpi) hot-melt inkjet technology to create wax-like models for making lost wax casting molds primarily for the jewelry industry, but also for some medical and industrial high-resolution casting applications. Stratasys invented non-inkjet fused deposition modeling (FDM) and gained a patent for it in 1989. In 2009, its patent expired, but Stratasys continues to hold the trademark for FDM.
ExOne of Irwin, Pennsylvania, is using Dimatix inkjet heads to bind powdered stainless-steel layer upon layer into functional metal objects. It then uses high heat to burn off the binder while sintering the stainless steel. The sintered objects are then infused with metal powder to fill any voids in a very high-temperature vacuum chamber. ExOne also manufactures 3D inkjet solutions for casting at its operations in Gersthofen, Germany.
Voxeljet of Friedberg, Germany, manufactures 3D printers that use inkjet printheads to bind powdered particles with its proprietary chemical binding agents to make parts and casting molds from a number of material types. It manufactures six 3D printers ranging from the VX200 designed for laboratories to the VX4000 that can product parts and models that are 13.1 x 6.6 x 3.3 feet, making it the largest 3D printer available.
Roland DGA (Irvine, California), which has offered a number of digitally controlled subtractive manufacturing devices for many years, recently entered the additive-manufacturing space with its first 3D printer. Roland has complemented its line of CNC milling devices, used in applications such as making dental prosthetics, with its monoFab Arm-10 rapid prototyping 3D printer, which uses a digital light processing layered projection system that builds small objects by UV curing liquid photopolymer jetted materials.
Inkjet Display Printing
Video display screens and panels have displaced cathode ray tube televisions and computer screens. Inkjet technology has played a role in the manufacture of LCD, LED, OLED, and PLED devices.
LCD screens use colored polymer filter material inkjet printed through specialized heads on the panel’s front plane. The printing process is usually conducted in controlled, dust-free environments. Inkjet systems for printing LCDs typically image large panels up to 8.2 x 8.2 feet that are then cut to provide a number of smaller panels. The specialized inkjet systems reportedly can print LCD panels at a rate of 3.3 feet per second.
Kateeva of Newark, California, founded in 2008, overcame technical hurdles and refined the process to cost competitively inkjet print OLED panels. Its YieldJet system prints in a nitrogen clean-room atmosphere to eliminate oxygen and particle contamination. The company has also advanced its inkjet printing mechanism to eliminate nozzle-to-nozzle non-uniformity and “mura” banding.