Fuchio Takeda

Model for a mono-component development process using edge enhancement effects of floating electrodes (electrophotography)

The contributions of the electrostatic and magnetic fields to the development characteristics of a monocomponent development system are analyzed. This development system uses a special development roller which comprises a development sleeve and a magnetic roller rotating at high speed. The analysis indicates that the magnetic field has a significant effect only on the toner particles which are charged below a certain level. The effect of the magnetic field on the toner particles, which are normally charged above a predetermined level, is negligible. The analysis of the magnetic field indicates that the presently used magnet roller, which rotates at high speed, can be replaced by a micropitch magnet roller, which rotates at low speed. The analysis also indicates that if the quality of the electric charge on the toner particles can be controlled, and that a nonmagnetic toner can also be used in the present development system. >

Design of electrostatic fields in a new monocomponent system

A method of designing electrostatic fields for the development of latent electrostatic images as used in a new monocomponent development system is described. This development system uses a development roller with a special structure in which a dielectric layer is formed on a conductive substrate, and a number of small independent electrodes are located on the surface of this dielectric layer. The system is capable of developing latent electrostatic images using only the high-spatial-frequency components of the latent electrostatic images for intensification so that reproduction of sharp line images and solid line images with broad-range density gradation is realized. This has been achieved by analysis of the electrostatic fields in a conventional development system, using a computer simulation based on the finite-element method. A variety of parameters in the system is determined so as to optimize the electrostatic field. >