Magnetic brush developing process and developer

摘要

Disclosed are a two-component type developer which is supplied to an area where a bias voltage of at least 250 V is applied, and a developing process using this developer. In this developer, by adjusting the particle size distribution of carrier particles within a specific range, occurrence of the so-called carrier dragging phenomenon of the transfer of the carrier together with the toner to a photosensitive material can be prevented. This adjustment of the particle size distribution is such that the content of carrier particles having a size smaller than 250 mesh is less than 8% by weight based on the entire carrier particles, the diameter D50 of the weight average particle size corresponding to 50% of the weight of the entire carrier particles is in the range of from 80 to 120 mu m and the difference between D25 and D75 is in the range of from 5 to 20 mu m.