The present invention provides a one-component development type developing
apparatus including a rotatable electrostatic latent image holding member
1 on the surface of which an electrostatic latent image is formed, and
using a toner 4 for rendering the electrostatic latent image visible,
wherein when the shape factor SF-1 of a toner fine particle is expressed
by: SF-1=(M.sup.2/A).times.(.pi./4).times.100 where A is the projected
area of the fine particle and M is the absolute maximum length of the
fine particle, then the shape factor SF-1 of the toner 4 is at least 100
and at most 140, and the developing apparatus includes: a toner holding
member 3 that is formed from a silicone rubber elastic material and that
is for holding the toner 4 and transporting it to the electrostatic
latent image holding member 1; a toner layer regulating member 9 for
forming the toner on the toner holding member 3 into a thin layer; and a
toner supply member 5 that is formed from a silicone rubber foam and that
rotates, in a position opposed to the toner holding member 3, in a
direction opposite to that of the toner holding member 3, and an AC
electric field is formed between the toner holding member 3 and the toner
supply member 5.