Non-magnetic one-component developer and development process

A non-magnetic one-component developer suitable for use in a development process in which a development roll for bearing a developer layer charged to the same polarity as the electric charge of a latent image formed on a photosensitive drum is disposed in a relation opposite to a photosensitive drum, and the remaining developer adhered to a non-latent-image area on the photosensitive drum is attracted toward the development roll at the same time as the development of a latent image on the photosensitive drum to remove the remaining developer, thereby cleaning the photosensitive drum, characterized in that the non-magnetic one-component developer comprises a binder resin and a colorant, and has the following physical properties:

• (a) the volume-average particle diameter (dv) ranging from 5 to 15 .mu.m;
• (b) the ratio (dv/dn) of the volume-average particle diameter (dv) to the number-average particle diameter (dn) ranging from 1.00 to 1.40;
• (c) the quotient (Sc/Sr) obtained by dividing the area (Sc) of a circle supposing the absolute maximum length of a particle is a diameter by the real projected area (Sr) of the particle ranging from 1.00 to 1.30;
• (d) the product (AxdnxD) of the specific surface area (A) (m.sup.2 /g) as measured in accordance with the BET method, the number-average particle diameter (dn) (.mu.m) and the true specific gravity (D) ranging from 5 to 10;
• and
• (e) the ratio (Q/A) of the charge level (Q) (.mu.c/g) to the specific surface area (A) ranging from 80 to 150,
• said non-magnetic one-component developer being substantially spherical from the conditions of (c) and (d).