A non-magnetic and non-contact AC development process has been numerically investigated using two-dimensional dynamic model. Simulation of toner dynamics in the development process was carried out using the Finite Difference Method (FDM) for the electric field calculation and the Distinct Element Method (DEM) for the calculation of charged toner motion in the electric field. Distribution of the electric charge density on a photoreceptor, the electrostatic latent image, was derived from a spot profile of a laser beam. Calculated results showed fairly good agreement with experiments.
The prevention of nozzle clogging caused by moisture evaporation at inkjet nozzles is an important issue in ensuring printing reliability. Although comprehending the physical properties of flying ink droplets is effective in analyzing jetting behavior, direct measurement is difficult because droplets are minute and flying is transient. Accordingly, observations were attempted on droplet vibrations produced when satellite droplets collide with main droplets. In result, it became possible to predict the physical properties of droplets in flight, and relationship between increased viscosity due to evaporation and the phenomenon of the jetting degradation was evaluated. In addition, piezoelectric driving power requirements were evaluated with inks that have different initial viscosity conditions. Although the main cause of jetting degradation following non-jetting-time is due to the rise in ink viscosity, results indicate the possibility that a thin ink layer of solid content formed on the nozzle may have slightly contributed to the degradation.
The offset printing accomplished rapid progress in these 15 years. The primary reason of this big progress in offset printing was owing to wide use of CTP. The register adjustment became automatically by combined CTP and the automatic plate exchange machine, and the color tuning was automated by the ink keys control system. Additionally, automation and standardization were developed with various aspects such as the hardware, software, and the material, etc., and it became a high productivity system that covered every field from the long run and low-cost operation to the short-run and quick delivery operation. On the other hand, the production and the consumption trends of the printing paper fail to rise in the developed nations, and the future demand shifts to the rising nations. Especially, Japan faces the population decline, and the consumption in the future will be decrease. It can be said that industrial structure that depends on domestic demand has seems like the limit. Moreover, the advanced know-how of graphic arts is not succeeded, because traditional skill is lost by the progress of digitalization. It is important to cultivate human who coordinates planning, manufacturing and circulation of graphic arts as a printing director. It may be said that the key factor holding the growth of future POD market and the graphic arts market lies on globalization and cultivation of the talented person.
In recent years, electrophotographic color printers, with their advance in speed and image quality, are being increasingly utilized in the printing market. However, print gloss of electrophotography outputs have been known to be less consistent with the gloss of the paper used, when compared to the print gloss of offset printing outputs. Gloss is also known to be determined by the topography, namely the three-dimensional profile, of the printed surface. In this report, it will be explained the difference between surface topography in offset printing and electrophotography.
The electrophotography has evaluated to the original making technology from the copying technology. Then, it has evolved into the value of the print from the value of the printing. In the electrophotography, several value added technologies will be cultivated for this purpose. This technology have included with the value added printing and the added value of the print. In this report, we would like to discuss about how to evaluate value added printing in the electrophotograhy.
Pigment has been applied as color material for ink jet for 10 years. At first, pigment for ink jet was selected from existing products for another application like offset ink, coatings. After that, pigment for ink jet use was developed to meet quality requirement in this use. In this paper, I explain organic pigment focusing on the difference between dyestuff and pigment, classification of organic pigment. Then, quality requirement to pigment for ink jet use, and action in producing pigment to meet these quality requirements are explained.