This paper has clarified the difference in image noise evaluation performance between the Wiener spectrum based method and the cooperative vision model based method by comparing both methods' noise evaluation values for the identical evaluated images composed of two groups of monochrome patch images with a uniform optical density. The first group and the second group consisted of images with the identical output resolution and various types of dot structure (or texture) and with various kinds of output resolution and the same type of dot structure, respectively. Consequently the following differences were clarified:(1)for the first group, the vision model based method was considerably superior in agreement with subjective judgments to the Wiener spectrum based method;(2)for the second group, both methods agreed well with subjective judgments;(3)the vision model based method specified viewpoints where image noise was conspicuous. The above results suggest that the vision model based method covers a wider range of application than the Wiener spectrum based method.
In order to realize both speedup and energy saving in color MFP, large shortening of warm-up time and keeping of fusing temperature in the color fusing system serve as subjects. In conventional color fuser, large heat resistance of fusing roller prevented warm-up time shortening and fusing temperature keeping. Therefore we developed new fusing technology that supplies thermal energy to the surface of fusing roller efficiently. This new fusing system uses external heating belt to heat the surface of fusing roller and optimal control of power source and fusing temperature matched to the heating system. Heating belt forms wide heating nip, so that the heating performance to fusing roller improves greatly. As the result of introducing this new technology to high-speed color fusing system, it achieves shortening warm-up time 67% and energy saving 44% compared with a conventional fuser.
The typical approach to develop an electrophotographic system is the trial and error approach. First of all, an undesirable phenomenon caused by toner properties in each elementary process of the electrophotographic system is observed, next, a relationship between the phenomenon and toner properties is guessed, and then, several modifications are tried and tested in order to find a good condition to control the electrophotographic system. If the relationship between the phenomenon and toner properties is explicit, the electrophotographic system will be developed more efficiently and the quality of the system will be higher than now. Therefore, in this paper, the generol view of physical properties and electrophotographic characteristics of a toner are described.
The development technologies, associated with nano-size particles, require instrument which has a wider range and whose range is extended to smaller particles. But instruments or methods are not necessarily determined by only the size of samples. So operators must choose them to meet their requirements. Now we try to explain in this article the methods, theory, and trend in characterization of particles.
In the toner manufacturing process there are many parameters such as particle shape, size, flowability, electrostatic property and so on to be monitored. Especially toner shape influences the adherability and the cleaning performance of the toner. Therefore it is very important to evaluate a toner shape to improve a printing quality on the paper. However conventional microscopic method takes time to measure and may cause human error. Sysmex recently developed a new technique to solve these problems. In this report a basic theory of an image analysis method and new technique based on a sheath flow particle image analysis method are introduced.
Powder flowability is a characteristic related to the change in the relative position of individual particles and is affected by many factors, such as adhesion, static and kinetic friction, gravitation and inertia forces, packing fraction, coordination number, particle diameter, shape, surface roughness and density;thus, it is difficult to theoretically estimate the flowability. To accurately evaluate the flowability, the powder should be tested by an appropriate method;however, the result is different depending on the viewpoint of the powder flow phenomena;for this reason, various methods for measuring powder flowability have been proposed. In this paper, the methods are categorized based on the mechanism of the measurement, and their features, measurement procedures and evaluation methods are explained.
Measurement apparatus of powder bed shear stress analyzer (NS-200) can measure the continuous shear force on a shared surface (friction force on a sheared surface) by simultaneously collecting data on the normal compression force. Powder properties (flowability (angle of internal friction), adhesion, compressibility and stress relaxation characteristics) of raw materials powder and semifinished product, used for toner, pharmaceutical compound, cosmetics and so on, can be evaluated with high precision and good reproducibility.
Specific surface area and pore size distribution are effective to evaluate the surface properties of toner and its composition materials, especially nano-scale structure overall. It differs from immediate information seen with the microscope etc., and averaged data on the entire sample can be obtained efficiently. Gas adsorption method and mercury porosimetry are both typical techniques effectively used for the measurements of specific surface area and pore size distribution. In this text, it explains an outline, an analytical method of these two techniques, and the application limit, etc.
A charge to mass ratio (q/m) measurement is one of the most critical measurements for electrophotography developers. A compact draw-off system provides substantial versatilities for q/m measurement of both dual and single component developers. There are two different Faraday cups equipped on the system so that it can measure each charge amount of both toner and carrier simultaneously for dual component developer. Nozzle unit, which consists of a dedicated Faraday cup itself, is designed to ensure an excellent maneuverability for separating toner and carrier through mesh on sample cell case for dual component toner. Direct toner sampling can be accomplished from toner charging roller and/or photoreceptor for single component toner. Additionally a toner concentration ratio between toner and carrier can be obtained. Extremely accurate q/m measurement is easily available at both R & D and manufacturing sites with this simple and user-friendly measurement system.
Apparatus (PAF-300N) for measuring adhesive force between fine particles uses contact needle to measure the adhesive force of single particle or between the particle and surface directly with high precision. Adhesive force between fine particles and plane (or cambered) surface can also be measured by centrifugal separation method. In this study, these two methods and their application examples are introduced.