ABSTRACT. We have simulated the evaporation behavior of multi-component liquid film in the forced convection field. For high-speed water-based inkjet printers, it is one of the important issues for the productivity to improve the drying performance. Impinging jets are often used for the printers. It is important to understand the evaporation behavior for the ink consisting of multi-component solvents in the impinging jet field, and numerical simulation is desired. However, it is difficult to analyze with a conventional solver. We have proposed the newly customized simulation model including the convection-diffusion equation of multi-component vapor concentrations and the convection equation of the liquid film in OpenFOAM. Comparison between simulation and experiment shows good agreement, and the model is useful to investigate drying performance for high-speed inkjet printers.

ABSTRACT. Inkjet printing technology has been developed for many commercial applications and is widely accepted as reliable manufacturing process. Under these circumstances, the varieties of ink properties and well-controlled drop formation are essential for the print quality. The objectives of this investigation are to boost efficient optimization of inkjet process. Herein the combination of a free surface simulation and a particle simulation was suggested for a reasonable evaluation of inkjet system. The evaluation technique enables us to predict and discuss print quality preceding experiments.

ABSTRACT. In the production of water-based pigment dispersions adsorbed with polymer dispersants on the surface of pigments, the adsorption distribution of ionic functional groups on the surface of pigment dispersions is measured by performing zeta potential measurement that eliminates the effects of Brown motion on pigment dispersions. This method is useful for designing and quality control of pigment dispersions with excellent jetting performance without actual long-term jetting test.

ABSTRACT. The evaporation rate of a pico-liter droplet of water was measured by a visualization system to evaluate the effect of surrounding droplets. This system consists of piezo inkjet head with linear actuator, camera, LED light, media, and thermo-hygrometer. The experimental results were compared with an existing evaluation equation and simulation results. In the simulation, the effect of surrounding droplets was evaluated with the consideration of surface temperature decrease due to evaporation. The results confirmed when the distance between droplets becomes closer, the effect of surrounding droplets becomes greater.

ABSTRACT. In previous report, we demonstrated that the laser drying system we developed using VCSEL unit had ability to reduce a cockling of thin coated paper by selectively drying only printed surface. In this study, we have built a system bench of a high-speed inkjet printing system implemented the laser drying unit, evaluated a cockling and fixability. Here, we report the experimental result and extracted problems, and applicability to high speed inkjet printing system. Furthermore, we will also mention about a trial to improve granularity of multi-color by controlling an interval of laser exposure and other application cases.

ABSTRACT. For inkjet printing system using water-based ink, paper deformation and roller offset resistance are highly difficult problems. In particular, two problems greatly affect of the quality of paper conveyance in high-speed cutsheet inkjet system. To solve these problems, the paper deformation is controlled by selecting the solvent in the ink, and roller offset resistance is solved by designing ink formulation of setting lower the dynamic surface tension in time domain of spreading. This paper describes the ink designing techniques that achieves both paper deformation and roller offset resistance. And this water-based ink designed by two techniques was equipped with TASKalfa Pro 15000 c.

ABSTRACT. “Samba JPC” provides the core components of FUJIFILM “Jet Press 750S” inkjet digital press, which achieves high image quality superior to offset printing. It consists of components such as a Printbar which equips “Samba”1200dpi MEMS printheads manufactured by FUJIFILM Dimatix Inc., a Fluid circulation unit, Image correction software, an Inline scanner, a printhead cleaner. Here, I report some unique technologies adopted in “Samba JPC” components which are realized by FUJIFILM’s inkjet technologies.

ABSTRACT. Ejection of the highly viscous liquid jets is required in inkjet printer, 3D printing, and automobile painting, among others. This study introduces a painting system that ejects highly viscous liquids as microjets. Our proposed device enabled us to paint letters on a car body panel with car paint of 100 Pa · s in zero shear viscosity. Furthermore, we investigated the jet velocity of the device for practical use. It turns out that the pressure impulse approach cannot predict the jet velocity trend because the actual position of the stagnation point is different from the predicted position. Therefore, we improved the jet-velocity model by considering mass conservation. This model can predict the jet velocity successfully.

ABSTRACT. We propose an entirely new printing system based on an optical vortex laser induced forward transfer (OV-LIFT) technology, which allows the production of microdroplets with a volume of ~10 picoliter formed of an extremely high viscosity ink (viscosity: 4Pa∙s). The microdroplets are forwarded and printed as a dot with a diameter of ~75 μm on a receiver film.

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ABSTRACT. Because inkjet printing can form thin films through liquid-type materials regardless of simple process and substrate size, it can be used to develop Soluble OLEDs and QLED, which are actively researched for high-tech industries [1]. During the inkjet printing process, the reliable drop of solutions is one of the important factors that determine the performance of display devices and the reliability of inkjet printing equipment.