Inkjet Technologies Moving Forward

By Andy Tribute

June 24th, 2008 -- The recent drupa highlighted the fact that inkjet technology is moving forward at a substantial pace and that the manufacturers of inkjet printers and presses are making good use of this new technology to bring new products to market.

What was interesting at drupa was that it was not just one inkjet technology that was moving forward but all of the technologies. By this I mean new developments in continuous ink jet (CIJ), in drop on demand (DOD) piezo and thermal inkjet, and in other technologies of DOD thermal and piezo inkjet using new types of inks such as Latex and gel inks. The following article summarises some of these developments and what they possibly may mean for the future of inkjet developments.

Continuous Inkjet

While there are a number of suppliers of CIJ technology only one, Kodak, really uses this technology for digital color printing applications. Up to now Kodak has been using a technology originally developed in the 1970s and substantially enhanced since that time. This technology of using 300 dpi 9-inch wide printheads with aqueous inks is used in the Kodak Versamark 3000 and 5000 families of presses for both monochrome and color printing. The same technology in narrower width heads is used for imprinting applications in many industries. The key development at drupa was the introduction of the STREAM CIJ printheads. These are a totally new technology that allows for higher speeds, better color quality and a wider range of inks to be used. The heads were shown imprinting in monochrome on the Muller Martini continuous feed offset press on the stand and this showed just how fast this technology of CIJ printing could print. The main showing however was the STREAM Concept Press and this showed the potential for high-quality color output. This color technology is not available yet and we shall have to wait until at least 2010 before Kodak brings it to market in a 24-inch wide press. It does however show the potential of this new form of CIJ in allowing high-speed quality presses to be built.

Most activity in inkjet at drupa however was in DOD technology. In this it could be said to be the battle of the printhead suppliers. Many of the new printers and presses being shown at drupa were using relatively new DOD printhead developments. Printheads are not all the same. Some of only suited for printing relatively low viscosity aqueous inks for highest speed applications whereas others can jet more viscous inks suitable for printing on a wide range of substrates. The following were some of the interesting inkjet developments on show and some of the products that used them.

Xaar – In many ways Xaar has to be seen as the most successful of the printhead suppliers in looking at the number of new products being shown using their latest Xaar 1001 printhead. This head that is designed to be built into wide format print arrays was being seen in a number of interesting products printing a wide variety of different inks. I have already written about many of these but I would highlight the FFEI Emblaze digital coater, the Xennia X-treme 9000 wide format single pass printer for printing ceramic tiles and other decorative products, and label printers from FFEI, Beijing Founder, Xennia and EFI Jetrion.

Dimatix

Dimatix, or Spectra as they are better known, did not have so many new products with its latest generation printheads. We saw the first implementation of the M-Series heads in the entry-level flatbed UV curable ink printer from Raster Printers producing excellent quality. The highlight from Dimatix was the new wide format printhead array in the Fujifilm JetPress 720. This used the new SAMBA inkjet technology to build a 1,200 dpi resolution grayscale printhead. This is a substantial leap forward in resolution and small drop size printing for piezo DOD inkjet. The fact it is also substantially manufactured using MEMS technology out of silicon shows real potential for further developments of this head.

Panasonic

The Panasonic wide format print array was seen in at least two different systems these being the Kodak Versamark VL2000 and the Impika presses. The Panasonic printhead array has two ink channels so it can print in two colors at 600 dpi at 75 meters/min or in one color at 150 meters per min. The interesting fact in this is to look at the Kodak Versamark VL2000, Kodak’s first DOD inkjet press, and inside one can see that it has two print head arrays. This means it is printing at 75 meters/min. There is however space for a second set of two print heads so one can envisage that there will be both an upgrade to the VL2000 and perhaps a second model that allows printing in full color at 150 meters/min. This would be the same speed as the current Kodak Versamark VX5000 Plus but the print is in a higher quality.

Kyocera

Kyocera’s new KJ4 Series printhead that is claimed to be the fastest DOD printhead available was being shown on both the Océ JetStream family and the Miyakoshi  MJP600 presses. These are basically the same presses manufactured by Miyakoshi but the control systems and drive electronics are Océ development for the JetStream presses. These heads are the widest piezo DOD heads available at a width of 4.25 inches and they are built up into wide format arrays, like other modern printheads. They have a running speed at 600 x 600 dpi of 150 meters/min but if the resolution is reduced to 600 x 480 dpi the speed increases to 200 meters/min. This is being offered with the Océ JetStream 3000 model. The printheads can also print slower and with a variable drop size from 4 to 21 picoliters. The printer from Miyakoshi was also being shown at drupa running with UV curable aqueous inks and this potentially opens up new applications for high-speed continuous feed inkjet printing.

Epson and Toshiba Tec

Both of these companies are also supplying printheads to a range of printer and press manufacturers. (Toshiba Tec licenses technology designs from Xaar but develops its own range of printheads). The main user of these two suppliers’ heads at drupa was Dainippon Screen. The Epson printheads are used in the Truepress Jet520 continuous feed color press and in the new Truepress JetSX B2 format sheetfed press. Screen was showing how different resolutions could be used with Epson heads. It introduced a high-speed version of the Truepress Jet520 running at double speed (1,680 A4 pages/min) where the resolution was 720 x 360 dpi. In the Truepress JetSX it runs the print heads at 1440 by 720 dpi to get higher quality. The change in resolution is in the direction of paper travel allowing a smaller or larger number of ink drops to be deployed. In the wide format UV printing area where Screen now has its Truepress Jet2500UV and Truepress Jet650UV, and also was showing of its prototype UV single pass printhead for special applications. It is believed Screen is using the latest Toshiba Tec CA4 printhead for these applications. The quality of imaging on the Truepress Jet650UV was outstanding and this is targeted at special applications like automotive displays that currently are screen-printed. Another user of the Toshiba Tec CA4 printheads is Olympus and they showed single pass printers at drupa. This was the OP-1cd Full Color Printer that prints a 12.4-inch width at 300 dpi with 8 gray levels at 33 meters/min. Two print engines can be linked together for full duplex printing. (This is basically the same print engine that Olympus developed for the RISO HC5500 that surprisingly was not at drupa).

HP

Much has been said about HP and their Scalable Printing Technology using thermal inkjet. We are now seeing this technology being rolled out in a range of products. We first saw it in desktop products like the OfficeJet Pro K550. It then appeared in the CM8060 MFP for enterprise printing. At drupa we saw Scalable Printing Technology move aggressively into the graphic arts space with two new products.  These were the HP Inkjet Web Press and the HP Designjet L65500 wide format printer. These showed how the power of the Scalable Printing Architecture printheads can be utilized in building either very wide format arrays for single pass printing or can be used in scanning print arrays for wide format printing. We can expect many more developments of this technology in both higher quality and higher speed in future.

New Inkjet Ink developments

The above reference to the HP Designjet L65500 printer is an example of how ink developments can change the use of inkjet. HP introduced its new Latex inks at drupa for use with this Designjet. This printer uses aqueous inks with a special formulation that allows them to print on non-absorbent substrates such as vinyl and also for printing for exterior applications. Latex ink will allow for a range of printers to be built, possibly under the HP Scitex brand, that use these new ecologically friendly inks. The other new ink developments came in an announcement from Océ and a technological briefing from Xerox. Océ announced Crystal Point inks. Crystal Point is where the ink is held as a solid called Océ TonerPearls that are stated to internally be similar to toner particles. They are converted to a gel inside the system. This is then imaged as a gel onto the substrate when an agent crystallizes them onto a wide range of substrates without having to use heat. The first implementation of this technology is in the Océ ColorWave 600 printer.

Xerox also has a technology in the market today using solid ink. This is the well-established technology used in many of the Xerox Phaser printers. In a technology preview at drupa Xerox spoke about the future Gel inks. This is where ink would be held as a gel and then converted to a liquid in the printer and then when imaged on any substrate would convert to a solid state without any heat being involved. Xerox sees this technology as a key for its future inkjet products.