Ricoh and Konica Minolta have both taken advantage of the inaugural Japan Inkjet Technology Fair in Tokyo, Japan, to show off new printheads, each aimed at different areas of industrial printing. Ricoh has mostly stuck with piezoelectric designs but its new Gelart printhead is a valve jet design.
The Gelart head stems from Ricoh’s acquisition of the Japanese company LAC back in 2018, as part of Ricoh’s strategy to grow its industrial print business. LAC had developed a number of printing systems able to print directly to the body or trailer of a truck or bus, as well as a wall printer and a coating machine.
We’re likely to be hearing a lot more about valve jet designs in the next few years because of their ability to handle very high viscosity fluids, which go beyond inks to include paints and a wide variety of functional fluids. They typically offer long throw distances and good reliability in industrial – including dusty and humid – conditions. These heads use a small number of very large nozzles. The fluid is forced through under pressure with a mechanical actuator to open the nozzle.
Ricoh has made a number of changes, principally to the actuator mechanism, which is now described as valve jet with piezo actuator, as well as improving the through flow and flow rate. It uses pressurised air to fill the ink chambers. The head itself is mostly stainless steel. It can jet horizontally and with a throw distance of around 20mm, which is suitable for printing in color to the sides of trucks and even aircraft as well as buildings, garage doors and retail units. Ricoh showed several interesting samples on its stand including corrugated metal sheets.
The Gelart head has just eight nozzles, with drop sizes ranging from 0.8 to 2.1 nanolitres – or 800 to 2100 picolitres. The firing frequency is up to 3.3khz.
There are two versions. The Type A has the eight nozzles in series, spaced at 8mm distances, giving a resolution of 3.3 nozzles per inch. It measures 116 x 11 x 92mm and weighs 450 grams. This is available now and Ricoh does have some projects in progress with customers.
Type B is physically bigger and includes recirculation. It’s also certified for protection against paint explosions, which apparently is a problem when trying to jet paint. The Type B head also has eight nozzles but they are staggered to give a higher resolution of 5npi, which should make it better suited for single pass applications. This is not yet available.
However, it can jet several types of paint, including solvent and water based automotive paint. Ryo Idehara, painting business section leader for Ricoh’s New Technology Development department, says, “Many companies want to do direct to shape so we think this head is a very important technology.”
Not to be outdone, Konica Minolta also brought a new printhead along to the show. The KM800 has been based on Panasonic’s thin film piezo technology, Konica Minolta having acquired Panasonic’s printhead division back in 2018. As the name suggests, the KM800 has 800 nozzles with a 56.4mm print width. It’s a four-level grayscale head, producing drop sizes from 5pl up to 22pl at a frequency of 18.2 kHz. It can run at 30mpm.
The resolution is 360dpi but it can also be configured for two color channels, each with 180dpi resolution. It’s been designed to work with oil and water-based solvents, with Atsushi Tomotake, senior technical advisor to Konica Minolta’s Inkjet component business, pointing out, “It does not have an internal heater so we don’t recommend to use UV ink.” It runs at room temperature.
It has a stainless steel nozzle plate. Konica Minolta has developed a new drive waveform for this head but customers are also free to write their own. In terms of viscosity, it can handle inks from 5-7mPa•s.
It’s aimed at industrial applications, including direct to shape, where its compact size will be an advantage. It has quite a long throw distance, from 10mm to 20mm, with samples available on the stand showing quite decent results at a range of distances, including up to 20mm. It can also jet horizontally.
It’s worth noting that there is a further version of this head, the KM1600, which is essentially two KM800s that have been combined together and which has 720npi resolution. This can handle up to four colors, each with 180npi.
Konica Minolta also had a couple of other recent heads on show, namely the analogue KM1024a SHE and KM1024a LHG-RC. These are primarily targeted at corrugated packaging, wall coverings, including the ability to print onto embossed media, and textile printing for both direct to garment and roll to roll. All of these heads, including the KM800, are available now.
The JITF event itself has managed to pack in a wide variety of inkjet-related technologies into a compact space, with a clear emphasis on industrial printing. I’ll write a fuller report later this week. The event has been timed to take place just before IGAS, which I will also cover later this month.
In the meantime, you can find further details on Ricoh’s printhead from industry.ricoh.com but not yet the Gelart which is too new to be listed, and on the KM800 head from konicaminolta.com, as well as the JITF2022 from ohno-inkjet.com.