Emergence is one of the key design principles in molecular robotics which aims to construct an artifact by means of the bottom-up fabrication of biomolecules as living things. In order to promote rational design of emergence necessary for molecular robotics, we have developed a virtual reality (VR) computational platform. The computational platform incorporates VR particle simulation, VR live control and interactive VR user interface running on GPU computing. The VR particle simulation is capable to emerge global dynamics in a massive swarm of objects represented by a compound of particles interacted by Lennard-Jones potential. The VR live control enables us to tune simulation parameters while running VR particle simulation. The interactive VR user interface enables us to intervene in simulation with virtual hands. GPU computing plays an essential role in achieving more than 90 frames per second in rendering while computing particle simulations in the millions.
This paper offers an overview of the recent progress in the simulation technology of electrophotography. Electrophotograpy is a complex process commonly used in copiers and faxes, as well as in digital printers. By utilizing highly efficient hardware and software, the simulation technology has been improved significantly, and practical use of numerical simulations for the development of electrophotographic machines becomes possible. Recently, physical mechanisms of various phenomena in the electrophotography have been clarified, and almost all the problems of electrophotography can be investigated with the numerical simulations. There already exist some overviews of the simulations of electrophotography, and this paper presents other simulation models and results to complement them.
Digital on-demand printing machines have been widely used in the commercial printing field. However, magnification errors of an image in the slow scanning direction at a secondary transfer with an elastic belt for intermediate transfer, which likely occur in various kinds of paper printing and environment, are unacceptable problems.
In this study, the mechanism of magnification errors is investigated by FEM (Finite Element Method) analysis. At first, friction characteristics of a secondary transfer nip are investigated experimentally. And then, motion and deformation of a paper, belts, and rollers with the friction characteristics are analyzed by FEM. Finally, calculated paper velocity is validated by comparison with experiments.
Canon has released LBP654C featuring an energy saving and a high-speed printing in April, 2017. This product accomplished a high-speed printing of up to 27 pages per minute with a quick first print of 8.6 seconds and a high print quality. For this achievement, an external heating fuser technology has been newly developed. Especially this new fuser technology contributes to the print quality uniformity and temperature rise on the non-paper region. In this paper, the improvement of the fuser performance has been confirmed through comparison with the conventional fuser by using a heat transfer simulation.
The electro-photography process involves various types of nip such as development nip, transfer nip, and cleaning nip. In this study, we developed a new method that can calculate the behavior of the particles inside these nips in a fairly simple manner. In this new method, the nip pressure distribution is simulated by creating a nip formed through layering rolls. Each roll is uniquely supported by a corresponding spring whose strength has been optimized. Using this method, the calculation was conducted to find out how the additives slip through a nip during the cleaning process. By examining the calculation result, we were able to figure out how the nip pressure affects the additives when they slip through a nip.
Development of a transfer process capable of application to various media utilizing numerical analysis was pursued in a tandem-electrostatic type liquid electrophotography system. To improve transfer efficiency to low capacitance media such as film label stocks, discharge control was studied by wrapping a continuous medium on an intermediate transfer roll in the pre-transfer area. Wrapping was found to have a trade-off relationship with image reproducibility, and dot distortion occurred in a particular image pattern. By simulating medium conveyance, it was found that when an image boundary with a different coefficient of friction passes through the transfer nip, the medium slips, and a shear force is applied to the toner image. By optimizing the medium conveyance parameters based on the analysis results, dot distortion was prevented. These preventative measures enabled achieving of high multi-transferability to various media.
This paper offers an overview of the recent progress in the simulation technology of inkjet printing. The droplet ejection process is very simple, but it is difficult to simulate in detail because of free surface, surface tension, contact angle, evaporation, bubble formation, and so on. However, by utilizing highly efficient hardware and software, the simulation has been improved significantly. Practical use of numerical simulations for better understanding of complicated phenomena and efficient development of inkjet technology become possible. There already exists a magnificent overview of the simulations of inkjet, and this paper presents other simulation examples to complement it.
Fuji Xerox has been developing high-speed inkjet continuous feed printing system for commercial printing market. Offset coated paper used there has relatively low permeability, which causes poor fixing performance and paper cockling in high print coverage. We have researched laser-drying technology with high energy density as a new drying system. This system can quickly heat only the ink without heating any moisture component in paper due to having peaky near-infrared wavelength. In this study, we demonstrate the laser-drying technology can restrain cockling in offset-coated papers (128gsm and 73gsm) using VCSEL as a laser system. Furthermore we develop cockling simulation model based on bi-metal model considering water swelling in printed area and anisotropy of paper fiber orientation. The influences of water swelling ratio and ink penetration depth on cockling profile are investigated and the conditions reproducing experimental results are also demonstrated in the case of with/without laser exposure.
J-OCTA is the integrated simulation system for soft materials, which includes various kinds of modeling tools and simulation engines to perform multiscale simulation. Recently some new functions have been added to the system to treat wider scale phenomena, e. g. quantum mechanics and nonlinear structural analysis based on continuum mechanics. In addition, combination with the data science is becoming important by the evolution of machine learning and deep learning technologies. By using chemical structures and materials properties database with experimental and many numbers of computer simulation data, Quantitative Structure-Property Relationship (QSPR) can be applied to design new materials. Latest updates of the software and case studies are introduced.
Polyimides are durable materials, possessing heat-resistance and a high mechanical strength. The polyimide in this study has a higher order structure which influences mechanical strength. For this reason, predicting mechanical properties from the higher order structure is a useful approach to designing materials and the study of such relationships is important. To study the mechanical property of the polyimide, we constructed coarse-grained simulation models of the polyimide and calculated the stress-strain curve. In this study we applied three models : a model taking into account molecular rigidity, a model taking into account attractive interaction that imitates stacking, and a model in which coarse-grained potential is improved based on full atomistic potential. From simulations, using the third model, the tendency of calculated values for the stress-strain curve ranging from the elastic region to the plastic region were consistent with experimental values.
Model-based development (MBD) is a powerful method of improving the system development process of industrial products and has recently been applied to the development of control systems in aerospace and automotive fields. In particular, in the automobile industry, MBD is an indispensable development method for satisfying required specifications, such as fuel consumption and exhaust gas regulations, and for developing a wide range of vehicles, such as hybrid and electric vehicles. Meanwhile, in the development of imaging technology, an increase in the load of the development process due to an increase in the size of the printer device and the complication of the control are major problems. It is an issue to improve the development efficiency by applying MBD. This paper introduces examples of applying MBD to the development of electrophotographic technology.
We summarized important points when metallic cross-sectional microstructure were observed by optical microscope and scanning electron microscope. Quality of a metallic cross-sectional microstructure depended on a specimen production process for observation. It was needed that a specimen for observation by an optical microscope and a scanning electron microscope was produced according to final observation results.
And type of the optical microscope and operating procedures influenced observation results strongly. In that case of the scanning electron microscope, location relationship between a metallic cross-sectional microstructure and electron scanning line position was very important. And we must make full use of a secondary electron image and a back scattered electron image in that case of scanning electron microscope.