We propose a green noise diffusion type digital watermarking method that embeds information that identifies a digital artwork (copyright information, database URL, etc.) into image data as a digital watermark, enabling copyright protection and originality verification of digital data and printed artworks. The embedded watermark has two types of green noise patterns with different coarseness. In the case of a copy, the finer watermark pattern disappears, making it possible to verify the originality. The green noise pattern is changed for each artwork, and a camouflage pattern is used, resulting in a secure digital watermark that protects against attacks such as removal or modification by third parties. We have confirmed the effectiveness of this method for digital artworks printed using Laxerop^TM technology based on electrophotography.

We found that the molecular weight of the polymer added to viscoelastic inks should be at least 0.15 million (g/mol) to display jetting behaviors typical of viscoelastic liquids, and at molecular weights near 1.5 million or higher, jetting becomes difficult. A satellite-free state was achieved during jetting when the molecular weight and concentration were appropriately selected, but the droplet velocity decreased as the driving frequency increased. This likely occurs because, at higher frequencies, the elastic strain generated when the jet breaks off remains on the meniscus side, hindering piezoelectric vibration. This was confirmed using a piezo-axial vibrating rheometer. After initializing the ink, different time intervals were given-time for the deformed polymer to relax-and the resulting droplet velocity was measured. As the time interval increased, the droplet velocity increased and stabilized, indicative of relaxation. Calculations of the relaxation time using Rouse and Zimm models produced similar values.

Digital textiles utilizing inkjet technology and other technologies are attracting attention from the perspective of contributing to the reduction of environmental loads toward the realization of a sustainable society. However, the ability of digital technology to produce a wide variety of products in small quantities and to respond immediately to trends has not always been utilized in the real world, and as a result, has not led to fundamental changes in supply chains and business models.

On the other hand, it has been pointed out that addressing these challenges may not necessarily be compatible with the pursuit of the “desirable cycle” in the butterfly diagram specifically, the pursuit of “basic designs that can be worn for a long time” in digital textiles.

This paper examines textile traceability as one approach to addressing these challenges, using it as a starting point to explore the potential and challenges of digital textiles for realizing a sustainable society, including a circular economy.

Introducing Konica Minolta's Single-Pass Printer, NASSENGER SP-1e, and the technology enhancing its Image Quality. Overview of O'ROBE ink for reactive dye preprocessing.

We have developed numerous inkjet inks using pigments to date.

In recent years, the Direct to Film (DTF) system, which uses inkjet printing to produce thermal transfer paper, has become popular both in Japan and overseas.

This paper will explain the overview of this system and how it differs from previous textile printing methods and conventional heat transfer paper production methods, as well as the differences in the finish of the final textile product.

Additionally, we addressed various issues within this system and developed and presented a novel adhesive layer formation method to tackle one of the challenges: the scattering of thermoplastic resin powder.

We will also introduce the development overview of a newly developed inkjet printing method that forms an adhesive layer, replacing the conventional resin powder spraying method.

Additionally, we will introduce our inkjet ink, Digiace, and related supplies for DTF.

A model was developed to estimate dynamic surface tension changes based on the diffusion equation, and numerical calculations and validation were performed. The model assumed one-dimensional surface area expansion, considering advection in the depth direction and mass transfer between the surface and bulk solution. The relationship between solute concentration at the surface and in the bulk was assumed to follow Langmuir-type behavior. Numerical calculations were conducted using the finite difference method, with parameters obtained from static surface tension measurements. To verify the model, calculations were performed in a system simulating dynamic surface tension measurement by the maximum bubble pressure method, and the results showed good agreement with experimental data in the Lifetime region where dynamic changes were observed. Furthermore, calculations under conditions assuming surfactants and humectants used in inkjet inks revealed significant differences in the Lifetime region for surface tension changes. Parameter studies suggested that solute concentration is a dominant influencing factor.

An equivalent circuit model with ink-circulating printhead is newly proposed. In the commercial and industrial printing market, digitization using inkjet technology is progressing. In this field, there is a demand for high reliability of jetting with ink-circulating printheads. In order to make full use of these ink-circulating printheads, a stable ink-circulation system is required. For this purpose, an equivalent circuit model is constructed that incorporates a state equation to reproduce the pump operation and pressure changes due to the compressibility of air and analysis is performed with the use of Microsoft Excel. After that, verification is carried out with an actual ink circulation system.

The RICOH Pro Z75 is a water-based pigment inkjet printer with automatic duplex printing capabilities, developed to promote the digitalization of the printing market. Conventionally, water-based pigment inkjet printers have faced the issue of paper waving when printing on thin paper or high-density images. An effective approach to reducing paper waving involves selectively heating the water-based pigment ink while keeping unprinted areas unheated. In this study, we developed a new drying technology that combines ultraviolet and infrared radiation aimed at reducing paper waving. We confirmed that ultraviolet radiation selectively heats only the water-based pigment ink. Furthermore, by combining infrared radiation, the technology also supports thick paper that requires higher drying energy. Equipped with this new drying technology, the RICOH Pro Z75 effectively suppresses paper waving while maintaining drying performance, enabling automatic duplex printing even on thin paper despite being a water-based pigment inkjet printer.

Elephantech Inc. mass-produces flexible printed circuits (“SustainaCircuits”) using a proprietary Pure Additive method based on inkjet deposition. This article presents ELP04-PCB, a high-precision, high-throughput inkjet printer, and NeuralJet, a machine-learning method for droplet-placement correction. ELP04-PCB combines a rigid mechanical frame, a～600 mm head array, an 830 mm × 500 mm stage, and precision motion control; the repeatability of landing position (σ) is 0.75 μm (main scan) and 0.44 μm (sub-scan). For mass production, the system integrates automatic maintenance, near-nozzle ink recirculation, per-head drive-voltage optimization for dot-size control, and jetting-state inspection with feedback to print data. NeuralJet models and compensates systematic errors from mechanics and nozzle individuality, enabling direct targeting of intended coordinates. These technologies are deployed in mass production at Elephantech's Nagoya facility with L/S (Line/Space) ＝100 μm/100 μm and will extend to rigid boards and semiconductor applications.

Continuous inkjet (CIJ) printers are widely used in industrial applications because they can operate reliably with fast-drying inks. In CIJ systems, the shape and uniformity of droplets generated from a liquid jet critically affect both print quality and system stability. However, predicting droplet formation remains challenging, since multiple physical parameters-such as nozzle geometry, ink properties, and vibration conditions-interact in a complex manner that cannot easily be captured by theory alone. In this study, we experimentally and numerically investigate how periodic fluctuations in the nozzle flow rate, induced by piezoelectric vibration, and variations in nozzle geometry influence the droplet formation process. Specifically, we observe droplet generation under different voltages and nozzle diameters and perform numerical simulations to evaluate the velocity distributions inside the nozzle. The results reveal that the internal jet-flow profile plays a crucial role in determining the breakup dynamics and the occurrence of satellite droplets in CIJ systems. These findings provide valuable insight into how internal nozzle flow conditions affect droplet stability and offer a guideline for optimizing droplet control in continuous inkjet printing.

Colloidal cesium halide perovskite nanocrystals (CsPbX₃NCs, where X is a halide) have garnered attention due to their exceptional luminescent properties, including high quantum yields and tunable band gaps. However, CsPbBr₃NCs are ionic crystals that decompose readily upon exposure to polar solvents such as water, limiting their use in aqueous environments. This study focuses on Cs₄PbBr₆NCs. Cs₄PbBr₆NCs possess a unique characteristic: at the interface between water and organic solvent, they convert into CsPbBr₃NCs, which exhibit higher water resistance than CsPbBr₃NCs synthesized directly by the hot injection method. This study aims to develop highly water-resistant CsPbBr₃NCs-containing polystyrene particles that remain stably dispersed in water via polymer encapsulation and conversion of Cs₄PbBr₆NCs. The extremely high water-resistant hybrid particles are prepared via a poor-solvent liquid-phase drying method, with cyclohexane containing Cs₄PbBr₆NCs and polystyrene as the dispersed phase and an aqueous solution of anionic surfactant as the continuous phase.

Couplants are crucial for effective ultrasonic testing, filling the air gaps between probe and specimen to enable sound propagation. Couplants mostly come in the form of liquids, gels, and adhesives. Therefore, they typically require repeated applications, can contaminate the specimen, need cleaning after use, thus preventing automation of ultrasonic testing and hampering inspection of locations with restricted physical access. Here we demonstrate the novel sliding dry couplant. The novel sliding dry couplant combines a soft material layer with a sliding material, which engages the specimen surface upon application of a load, while sliding freely along the surface when the load is released. The soft material layer squeezes through the sliding material to engage the specimen surface upon application of a load, contacting the surface of the specimen and enabling ultrasonic inspection. When the load is released, the soft material retracts without leaving any residue, and the novel sliding dry couplant can slide over the surface.

In this manuscript, the discipline, the domestic and international history, the target range, and the role of Human Factors and Ergonomics (HFE) were overviewed in order to help the members of the Imaging Society of Japan understand HFE. Several kinds of human characteristics, which should be considered in ergonomics design, were outlined as follows: physical characteristics (static and dynamic morphological characteristics, motion and movement characteristics,), physiological ones (visual and auditory characteristics, physiological response characteristics), cognitive ones (performance characteristics in human information processing), and psychological characteristics (psychological effects characteristics in human information processing). The characteristics of Human error and elderly characteristics were also outlined.