Kyocera has announced a new printhead, the KJ4B-EX1200-RC, which has been designed for use with aqueous inks, and is targeted at commercial, packaging and textile printing applications.
The new head appears to be an improved version of the KJ4B EX1200 that was announced in January 2020, and which I’ve previously covered, and which I believe has been subsequently discontinued back in 2022. Instead, the new KJ4B-EX1200 RC has a slightly more compact body, measuring 200 x 58.5 x 79.3mm but with the same print width of 108.3mm and the same 5116 nozzles, equivalent to 1200 npi nozzle density.
This printhead features full recirculation of fluid past the nozzle plate, which should help limit the potential for nozzles to become clogged. It appears to have a single ink channel and is capable of delivering up to 1200 dpi resolution. It’s said to run at up to 101.6mpm.
Most importantly, this new head has a native drop size of 2pl and can produce up to 4pl drops with a maximum jetting frequency of 80 kHz. This gives a lot of flexibility for OEMs in developing waveforms to optimise the drop volumes for their particular application. It also means much higher ink laydown, which Kyocera has suggested is useful for delivering fluids with more functionality such as faster drying for commercial printing or pigment inks for textiles. This is a growing trend in inkjet as water-based inks are being used for a wider variety of applications, such as printing onto coated papers and films, while presses are getting faster at high resolution, meaning there’s also a demand for faster drying of those inks.
However, this level of functionality would also imply the ability to handle high viscosity inks, though the recommended ink viscosity range for the new printhead is 5.0-6.0mPa*s. There’s heating on the head, which is typically used to control the viscosity of the ink immediately prior to jetting. Interestingly, there is also water cooling on the head to protect the electronic board from over-heating.
The KJ4B heads are designed for high speed printing of water-based inks, which is primarily commercial, packaging and textile printing applications though Kyocera’s press release also mentions building materials. The EX platform is the latest iteration of Kyocera’s bulk piezo approach and benefits from Kyocera’s unique monolithic piezo actuator. The Kyocera name derives from Kyoto Ceramics, and the company has used its expertise in ceramics to create a dense polycrystalline ceramic actuator using thin piezoelectric ceramic substrates. The result is a very thin piezo electric actuator plate that measures 116mm long and 34mm wide with a depth of just 0.04mm, which sits above the ink chambers within the head. By precisely controlling the voltage applied to this actuator, through the waveform and drive electronics, Kyocera is able to subtly control the shape of this actuator to eject the ink from each of the ink chambers. I’ve already covered this in a previous report.
The new printhead uses the same electrical interface as the much older KJ4B 1200, which should make it easier for OEMs to upgrade their machines to the newer model. But it’s worth noting that the EX1200-RC has a narrower print swathe to the older KJ4B 1200 head.
Kyocera says that the KJ4B-EX1200-RC head will be available from April 2024. However, I believe that it may already be in use by some printer OEMs. It appears to me that this is the same printhead that’s been used by Kyocera’s Nixka Inkjet Systems subsidiary for its Lenix print engine, which KNIS referred to as the previously discontinued KJ4B EX1200.
The new head has been developed at Kyocera’s Kagoshima Kokubu plant in Japan. You can find some further details on Kyocera’s printhead range from kyocera.com.
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