The Poggendorff illusion is an illusion in which lines appear to shift when the middle part of an oblique line is hidden by an obstacle. In this study, we evaluated the effect of the width of the obstacle, the angle between the obstacle and the oblique line by using subjective evaluations. Our experiments showed that the larger the width of the obstacle, the larger the illusion rate, and that the closer the angle between the obstacle and the oblique line, the larger the illusion rate. We introduced the supposition that accumulated experiences of observation in 3D space for an oblique line hidden by a distant obstacle must bring us a curious impression when we observe an oblique line hidden by an obstacle at the same plane written as 2D picture. Our experimental results support this supposition. As an application of the Poggendorff illusion, we investigated the appearance of diagonal lines across joint gap in tiled displays. It was shown that in the arrangement in which the starting position of the slanted line was intentionally shifted based on the prediction of the Poggendorff illusion rate, the viewer's discomfort was reduced compared to the arrangement in which the slanted line was placed on a straight line.

In the design of the image formation process of electrophotographic technology, it is important to accurately measure the surface potential of the electrophotographic photoreceptor. Furthermore, it is required to improve the performance of surface potential measurement in high response and micro area for high speed and high image quality. In this article, we report an overview about visualization and measurement technology of surface potential behavior and electrostatic latent image profile on photoreceptor, which are important elements for improvement and stabilization of image quality, and comparative verification of experimental results by photo-induced decay characteristic simulation.

Cleaning blades are required to be improved in the qualities of durability and reliability. These qualities are correlated with the internal stress generated inside the cleaning blades, with the horizontal component of the internal stress correlating to durability and the vertical component of the internal stress correlating to reliability. Therefore, analysis of the internal stress of cleaning blade can lead to the achievement of the quality improvements required of cleaning blades. A suitable method to measuring internal stress of cleaning blade is the photoelastic method, because the cleaning blade has transparent body. As an analysis technology using photoelastic method, we have developed a technology to capture high-speed photoelastic videos and analyze the vibration of internal stress at the edge of the cleaning blade and the uniformity of internal stress in the axial direction. Based on these results, we have built schemes to analyze the durability and reliability of cleaning blade.

In the fixing process of heating and pressurization used in electrophotography, toner is brought into contact with the heated fixing material and fixed to the media by pressurizing. In this system, when the media passes through the fixing device and the toner is peeled off from the fixing material, it is necessary to design in a state with good mold releasability. We developed a peeling test machine as a measurement technique to evaluate the release property of toner and fixing material. This method is used in the evaluation test of adhesive, and the release property of toner and fixing material can be evaluated by using this peeling test machine. In this paper, mechanism and measuring method of this peeling test machine, and toner release property under various conditions are explained.

In inkjet printing, the area of droplet penetration affects both print quality and energy efficiency, making the control of the penetration area crucial for enhancing the performance of inkjet printing. To achieve precise control over ink penetration, it is necessary to elucidate the behavior of ink (droplet) penetration. However, most existing studies have been limited to two-dimensional measurements of the droplet penetration area, either from the surface or in cross-section. Our research group has developed dyes and pigment inks that can be imaged using X-ray CT (computational tomography), along with a high-resolution X-ray CT measurement method, enabling the measurement of the penetration area within various media of single micro-droplets. This paper discusses the X-ray CT imaging technique and explains the penetration characteristics of dye and pigment inks in various media.

When printing on plain paper by inkjet, the ink permeates into the paper and colorant in the ink fix to fibers. It is important to understand a relation between the distribution of fixed colorant and surface visibility quantitatively for aiming for high quality of printed images. In this study, printings were sliced using a microtome and broken down into thin slices. Then we devised a method to quantitatively analyze an amount of fixed colorant at each depth by computing pixel value of microscopic images of thin slices. As a result of applying the method to some condition printings, we found that the amount of fixed colorant increases and turn to decrease with becoming deep. Also, when using two-color inks, the distribution of each colorant change with the sequence and time interval of ink transfer.

Metal additive manufacturing (AM) is being employed in industries because it creates metal objects of any shape. The applicability of metal AM in industries will improve if related costs and reliability issues are addressed. Powder bed fusion (PBF), a metal AM technique, is slower than other metal AM methods but offers several advantages. It excels at fine modeling, generates shapes that cannot be generated using conventional methods, and reduces post-processing workload. PBF is currently being vigorously researched. In-process inspection is necessary to reduce PBF-related costs, resources, and time and enhance the reliability of formed products. Laser ultrasonics (LU) generates acoustic waves without contact and is a promising technique adaptable to PBF. This article introduces the concept of PBF with an in-process inspection system and summarizes elemental inspection techniques, such as LU-based subsurface-defect detection in AM products and evaluation of the acoustic characteristics of solid-liquid phase transition in lead-free solder.

High-speed cameras can conclusively capture and record instantaneous behavior that is difficult to capture with ordinary video cameras. In recent years, the use of high-speed cameras has been expanding not only with the improvement of their shooting performance, but also with the miniaturization of the camera itself and the combination with external devices and image analysis software.

This presentation will introduce such examples using actual high-speed video footage.