Quantum dot light emitting diodes (QLEDs) with a structure of ITO (indium tin oxide)/poly (3,4-ethylenedioxythiophene) polystyrene sulfonate/hole transport layer/QD (quantum dot)/electron transport layer/Al using CdSe QD were fabricated, and machine learning was used to predict the efficiency of the QLEDs. A machine learning model was constructed to relate the efficiency of the QLEDs and the electronic transport properties of the QLEDs using a large number of data generated by device simulation. The efficiency limiting factors found by the machine learning model are consistent with those found experimentally. In addition, the machine learning model predicts the electronic properties of the hole transport layer for the fabrication of high-efficiency CdSe QLEDs.

We have prepared organic conducting nanocomposite inks consist of polypyrrole and indium tin oxide (ITO). Different oxidants such as ferric chloride (FeCl₃) and ammonium persulphate ( (NH₄) ₂S₂O₈) were used. The nanocomposite of polypyrrole and ITO represent potentially useful processable forms of polypyrrole, normally intractable conducting polymers. The produced by polypyrrole-ITO samples were characterized by using different techniques such as the electrical resistivity by four probe technique, elemental analysis (EA), dynamic light scattering (DLS), X-ray photoelectron spectroscopy (XPS), and scanning electron mictoscopy (SEM). The performance of the oxidants has been investigated and compared. It has been observed that the polypyrrole-ITO samples containing FeCl₃ as an oxidant achieved higher conductivity relative to those containing (NH₄)₂S₂O₈ as another oxidant.

The dry process of a solution film enclosed with a cylindrical wall is numerically simulated to investigate the effect of solution-derived Marangoni flow on the deformation of the free surface. When no Marangoni flow occurs, drying of the liquid progresses while the free surface keeps a spherical cap. As a result, the free surface firstly reaches the center of the bottom surface, and subsequently forms a solid layer from the center toward the wall. When Marangoni flow occurs, Marangoni forces deform and flatten the free surface on the center. As the volume of the liquid decreases to 20%, cavities are developed near the wall. The cavities at a periphery of the solid layer were experimentally reported in the previous work. The calculations thus reveal the cavities results from Marangoni deformation. Moreover, the mechanism of lateral bulk flows derived by Marangoni deformation is discussed.

Relation between evaporation and evolution of ink viscosity in the nozzle of inkjet head is investigated with an experiment and a numerical simulation. Nozzle clogging due to evaporation is a great concern for developing a robust inkjet head. Theoretical and experimental investigations would be useful for understanding the phenomenon and for taking measures it. Experiments with laser doppler vibrometer (LDV) method estimates the viscosity of nozzle for various combinations of ink and inkjet head. The effect of meniscus-vibration method for suppressing nozzle clogging is also investigated experimentally. Viscosity can be estimated from one-dimensional convection-diffusion simulation, and the results show good agreement with the experiments. The simulation can investigate a robust nozzle condition against ink clogging, and it is useful to design a configuration of inkjet head.

The electric field excitation type powder electroluminescent (EL) device has excellent environmental resistance, it is expected to be applied to a multifunctional surface emitting device. We have reported that the EL properties in bottom-emission structured powder EL device are determined by both the substrate surface roughness and transmittance. However, it was not possible to evaluate the effect of these substrate properties on the EL properties separately. To clarify the effect of surface roughness, we fabricated a top-emission structured powder EL device, which is unaffected by substrate transmittance, on an abrasive paper. As a result, the EL properties increased inversely with decreasing surface roughness. Furthermore, the electric field analysis indicates that the changes in film thickness resulting from surface roughness determine the EL properties.

In order to protect the global environment from global warming and ocean plastic problems, it is necessary to use sustainable resources and be able to recycle them. Therefore, we considered making it transparent like plastic while taking advantage of paper's recyclable properties. In order to make the paper transparent, a resin with a refractive index close to that of paper was selected, and the type of pulp was optimized. It was also found that whether or not it can be recycled is determined by the resin content.

Furthermore, we investigated ways to increase visual transparency by printing a checkered pattern reminiscent of a black screen door, and found that printing a checkered pattern increases transparency. This is thought to be because while the reflectance of the surface decreases, transmitted light becomes difficult to diffuse. This was confirmed by measuring the degree of diffusion of transmitted light.

We have developed a technology to react thin film with sulfide such as potassium sulfide, and to exhibit various colors due to the interference of silver sulfide layers. We call this colored silver thin film “decorative silver film” because we are considering its application in the so-called decorative technology field. Since this decorative silver film is insoluble in water and does not elute silver ions, it was thought that it would not exhibit antimicrobial properties unlike conventional silver films. However, in a previous study, we found that this decorated silver film also has antimicrobial activity comparable to that of conventional silver film. In this study, we evaluated the antiviral activity against bacteriophage ϕ6, a virus similar to Covid-19, and confirmed that the decorated silver film exhibits antiviral activity against this virus equivalent to that of silver film.

ITMA (International Textile Machinery Association), a textile-related machinery exhibition held once every four years in Europe (once every two years in Asia), was held in Milan as scheduled. This exhibition is an exhibition of all kinds of textile machinery, including machines that make thread, machines that weave and knit cloth, and machines that print. Due to the coronavirus pandemic, ITMA has not been held in Asia since 2019, and this was the first textile machinery exhibition in the world in a long time, and we were able to see a new direction different from conventional exhibitions. In this article, we will discuss each company's response to pigment printing, which has become the mainstream at this exhibition, how the number of single-pass printing machines has decreased dramatically, and how they are responding to the increasing number of large scanning machines, as well as new decorations such as double-sided, three-dimensional, and metallic. We will report on the future of textile printing as seen at ITMA, including its expansion into printing.

ITMA (Textile & Garment Technology Exhibition) is the world's largest international textile & garment technology trade show. At ITMA, researchers present their cutting-edge technologies, and its expected customers are textile mills. The author visited Print & Ink Hall at ITMA2023, not as an expected customer, but as one of those customers in the downstream of the Japanese textile and apparel industries.

With the distribution system collapsing and digital transformation not taking root in the industries, inkjet printing has not been effectively or efficiently used by downstream customers in Japan. The author believes that it is one of the important roles of inkjet printer makers to adapt digital textiles into the industries and make the most of it for the future.

In this paper, the author shares the impact of the exhibition and will propose the expected future roles of the printer makers in the Japanese textile and apparel industries.

After going through the COVID-19, society is undergoing an accelerating transformation not only in terms of material aspects but also in terms of values. ITMA2023, which was held there, was a very manufacturer-driven exhibition. Characteristics of the inkjet printers at this exhibition include the development of pigment printers in line with the trend of sustainability and the rise of decorative value-added printing. In other words, the industrialization of equipment is progressing at an accelerated pace.

In this article, I will first look back on ITMA2023 from the perspective of a dye factory. At the same time, I would like to discuss the future direction that has emerged, the challenges to that direction, and what I expect from the exhibiting companies based on the issues that have emerged.

Speaking about textile digital printing today and the technologies used within this market looks a little bit odd at the first sight. In a such competitive and growing market the expectation is to have some new emerging technologies every year, like in any digital revolution, but the reality appears to be quite different with technologies well established and nearly identical to the ones used in early 2000. In particular, we have got great steps forward in printing speed and inks reliability but the overall process and the print quality are not so different than the Mimaki TX1 of the 1999 based on EPSON printheads.

Pattern is still printed onto fabrics mainly by analog screen printing. Digital printing by inkjet printer was begun around the end of 20th century, but its progress had been slow. Its ratio in the market has remained in a few percent. Production rates in the conventional inkjet printer, even in the fastest ones, were less than 10% of the screen printers. The small productivity limited the progress of digitalization. Recently a high-speed inkjet printing technology, so-called “single pass printing technology,” has been developed. The technology has made the inkjet printer much faster in production rate, and it has accelerated the conversion from analog to digital. In addition, many vendors have showcased pigment solution at ITMA 2023.

In this paper, we will explain about the recent trend of digital printing business.

What society and the textile industry are looking for from textile printing suppliers now. Products and production systems must be sustainable.

I believe that it is a question of whether we are working to protect people and the environment and consider the future of the earth.

While the textile industry faces many problems such as waste disposal, water pollution, and harsh working conditions, industry stakeholders are meeting many of the items listed in the SDGs. Our top priority is to create a recycling-oriented society that delivers safe and secure products to consumers, and also regenerates them after use, returns them to yarn, and manufactures cloth.

Under these circumstances, each country is tightening legal regulations regarding water quality, chemical substances, and disposal, and certifications such as OEKO-TEX^® are gradually becoming a requirement for safety certification.

This document is noted about various regulations surrounding digital textiles.

Brother's “At your side 2030,” the Brother Group's vision for FY2030, calls for expansion in the industrial field. And under CS B2024, Brother's mid-term strategy through FY2024 to achieve this vision, the company is promoting activities aimed at “evolving printing technology with inkjet at its core and expanding its range of applications” to create a “future business portfolio”.

The “WF1-L640,” Brother's first latex wide-format printer for sign and display applications, is a product that takes on the challenge of a new area by utilizing its in-house ink and print head technologies cultivated through the development of garment printers for printing on fabric.

The newly developed latex ink used in the “WF1-L640” realizes a wide color gamut and richly expressive colors, while at the same time being highly weather resistant and environmentally friendly as it is a water-based ink that can be used for outdoor advertising materials. It is an eco-friendly product that can be used safely in restaurants, educational institutions, medical institutions, etc.