The Shearing Transfer Method works such that the liquid color toner images are moved from the photoreceptor surface onto the intermediate transfer medium by applying shear stress. By using this method, stable operation and high-quality image output have been realized in liquid color toner electrophotography. Although the working mechanism of this transfer process has been reported previously, why the transfer process works well when the toner is slightly wetted, but not when it is completely dried or soaked, has not been explained adequately until now. This phenomenon is analyzed in the present paper. The derived conclusion is that it is attributable to liquid bridge formation, which is related to the cohesion force, the liquid content, and the transfer efficiency.
A new objective image quality evaluation method for image noise has been developed. Its metrics are based on the output responses from a cooperative human vision model which can theoretically simulate accommodative responses and various kinds of perceptual responses. In order to examine the effectiveness of the proposed evaluation method, it is applied to noise evaluation for the copies of uniform density patch images that are made by using three kinds of digital color copying machines. The following results were obtained: (1)the vision model theoretically predicted how the human vision system responded to the patch images' noise at every viewpoint; (2)the mean-square-log error of the vision model's evaluation function value correlated closely with the psychological image noise score for the patch images (absolute correlation coefficient>0.96). These results suggest that the proposed method is effective as an objective evaluation method for image noise and that perceptual responses in the subjective evaluation process are appropriately reflected in its metrics.
Recently the intermediate transfer belt system is very popular in the color electrophotography. In order to analyze this system it is necessary to consider the electric field, resistance of the belt and discharge phenomena in the vicinity of the nip, and the two-dimensional simulation is desired to consider these phenomena. Two-dimensional electric field simulation program is developed in order to make clear the effect of these phenomena in this transfer system. Poisson's equation of electrostatic field and Ohm's law are solved using finite difference method on the boundary-fitted coordinate system. As the potential distribution, electric field strength, the amount of charge by discharge can be obtained from the calculation, this simulation program is useful for developing this transfer system and analyzing phenomena happened in this system.