Abstract
The mechanism of the Canon Toner Projection Development is studied. The technical features of TPD comprise two processes; one is to smoothly coast a toner applicating sleeve which involves permanent magnets in it with electrically insulative and magnetic toner, and the other is to oppose the sleeve to the image bearing member retaining the gap between them, which is larger than the thickness of the toner layer and to accomplish the development. It is the characteristic of TPD that toner goes back and forth between the toner applicator and the image bearing member both in the image areas and in the non-image areas under the influence of the external alternating electric field.
The model of the development is made with some simplifications considereing the following forces which act on the toner particles; the first is electric forces which originate from both the image bearing member and the alternating electric field, the second is image force which originates from the tridoelectric charge of the toner layer, and the last is magnetic force.
The numerical calculation of the V-D characteristic well agrees with the experimental results, which confirms the validity of the model. According to this model, V-D characteristics of TPD depend on mainly the image force of the toner charge.
