A new energy-saving electrostatic imaging process requiring no toner thermal fusing is proposed. Toner images are formed using an electrostatic transfer process on a specific type of transfer sheet. On the surface of the sheet fine parallel grooves are formed. The grooves are separated by thin walls. These thin walls can be called micro-walls that are 2-5 times higher than the toner particle size. The transferred toner particles are attracted to the bottom of the grooves by the electrostatic image force, and the toner images formed in the grooves are protected by the wall-like boundaries (micro-walls) between the grooves. The formed images are stable with gentle handling for reading or inspection.
In the image-forming electrostatic transfer process, some toner particles are transferred to the top of the walls and not in the grooves. Because these toner particles located on the wall tops are not protected, they are eliminated from the sheet by a cleaner roller utilizing the electrostatic image force on the roller surface.
The toner images in the grooves on the transfer sheet are erased by an electrostatic method using a biased magnetic brush with a magnetic developer attracting the charged toner particles of the images.
The erased transfer sheets and the collected toner can be repeatedly used for the next images and are not wasted.

View full abstract

The organic photosensor used in Elgraphy, a novel image acquisition system that combines electrophotography and liquid crystal technology, not only generates a sufficient dark current but exhibits photocurrent amplification as well. A single-layer photosensor made by mixing Charge Transport Materials (CTMs) into the Charge Generation Layer (CGL) exhibits both the enhanced photocarrier generation and larger photocurrent amplification. The magnitude of this effect depends on the ionization potentials of the CTMs used as additives, and is thought to result from a lowering of the barrier to hole injection brought about by the generation of oxygen acceptor sites at the electrode/photosensor interface. In illuminated areas, the generation of photocarriers is thought to further lower the barrier, thus increasing photocurrent amplification. These results demonstrate that the use of various combinations of CTMs with different ionization potentials is an effective way to control the dark current in the Elgraphy photosensor.

View full abstract

In the organic photosensor used for Elgraphy (Elgraphy photosensor), electrons trapped at the electrode/photoconductive layer interface promote hole injection from the electrode, thereby enhancing the photocurrent amplification. The authors have shown that the dark current of the Elgraphy photosensor, which is made by stacking a Charge Generation Layer (CGL) and a Charge Transport Layer (CTL) on a transparent electrode, can be changed by altering the composition of the CGL through the use of a mixture of various binder resins. Furthermore, the addition of an electron acceptor material with an electron affinity greater than 1 eV has proven to be effective in increasing the dark and photoamplification currents. This technique enables even a photosensor with blocking characteristics to be given a photocurrent amplification capability. Careful selection of both the type and amount of electron acceptor material provides good control, and improves the long-term stability, of the dark current.

View full abstract

Influence of charge control agent (CCA) in toners on their tribocharging characteristics was examined experimentally. Three kinds of toners were prepared using three kinds of CCA (azo ion compound) differing in the particle size. It was found that the particle size of original CCA did not influence on the saturated Q/M of toners but influenced on the tribocharging rate. Chemical analysis, particle analyzer analysis and optical microscope observation of fused toner layers suggested that the particle size of CCA on the toner surface was larger than that inside the toner. The tribocharging was faster for the toner containing surface CCA with a larger particle size. It is concluded that the particle size of toner surface CCA as well as the total amount of CCA is an important factor which determines the tribocharging rate of toners.

View full abstract

A seamless three-dimensional (3D)Gamma-Compression Gamut Mapping Algorithm (GMA) is proposed. Currently Gamma-Compression GMA has been designed to work in two-dimensional (2D) Lightness-Chrominance planes segmented by primary and secondary color hues. The advanced 3D GMA is expected to work in 3D uniform color space without color segmentation.
This paper describes a 3D GMA based on the concept of Image-dependent. Considering the color gamuts' relations between source image and printing device, the Gamma-Compression GMA is applied in relation to the 3D shell shapes in CIEL*a*b* space. 3D shell shapes of source image and printer device are formed by connecting the most outside color points on their gamut surfaces. The surface polygon meshes or parametric cubic Spline surfaces are built up from these most outside color points, and true seamless 3D mapping is performed.
It is shown that the 3D GMA coupled with nonlinear compression and multi-mapping directions resulted in the better rendition than 2D GMA. Two kinds of methods, Image Lightness Division (ILD) and Focal Lightness Scaling (FLS), are introduced to find the optimum mapping directions.

View full abstract

The authors developed the novel ink-jet technology using electrostatic force. The ink contains positively or negatively charged colorants which disperse in a highly resistive solvent. The injection needle with an inner diameter of more than 500μm is the ink-jet electrode. When the signal and bias voltage with the same polarity as that of the colorants is applied to the injection needle, the charged ink droplets are ejected onto the paper. One of the features of this technology is that the minute ink droplets are ejected from a large aperture. It means that fewer clogging problems are expected than conventional ink-jet technologies. More than 2000dpi resolution can be achieved with this technology. The dot-size can be modulated by pulse-width modulation. Furthermore, the authors observed the concentration effect of the ink when it is ejected.
In this paper the features of the novel ink-jet technology, experimental setup, observation results, and the printing samples are described.

View full abstract

In recent years, the innovative progress in inkjet head technology has made the largest contribution in improving print quality in producing photo-quality prints by introducing extremely fine droplets. This rapid and drastic progress, that has reduced the minimum droplet size by a factor of ten in the last five years, has made the inkjet a widespread device and has been introducing this technology into new market fields and application areas.
This paper focuses on Epson’s Micro Piezo Head Technology and describes the structure of Epson’s piezo print heads: MACH, the dynamics analysis and ink meniscus control basics for understanding the fine droplet technology of piezo heads, and then the head structure and driving signal designing for fine droplets generation.

View full abstract

Ab initio structure prediction of molecular crystals is polarized between the potentially high impact on materials design on one side, and the limitations of the currently available methods and theoretical models on the other side. In some way organic pigments offer an escape from these limitations because of their low molecular flexibility.
The focus of this paper is to exemplify pragmatic approaches in this subject, which include the validation of force fields and the analysis of specific intermolecular interactions. A calculation of possible crystal structures of a terrylene derivative is described and the predictive power of such a global minimization discussed with respect to energy ranking and knowledge-based selection criteria.

View full abstract