Developing apparatus having a toner regulating member with an extended lifetime

A developing apparatus using monocomponent developer, comprising:

• monocomponent magnetic toner;
• a developer carrying body for carrying and transporting said monocomponent magnetic toner;
• magnetic field generation means located inside said developer carrying body;
• developer supply means for supplying said developer carrying body with said monocomponent magnetic toner;
• and
• a flexible metal trimming member mounted inside said developer supply means for pressing a rubber sliding part affixed to one end of said trimming member against an outer surface of said developer carrying body to slidingly engage said developer carrying body;
• wherein the following condition is met:
• aP>bP
• where, P comprises a contact point of said sliding part with said developer carrying body, a comprises an upstream end position of said sliding part in a direction of rotation of said developer carrying body, b comprises a downstream end position of said sliding part in the direction of rotation of said developer carrying body, aP comprises a distance between the upstream end position a and the contact point P, and bP comprises a distance between the downstream end position b and the contact point P, and wherein the following conditions are met:
• w.gtoreq.10t, r>w
• where, w comprises a width of said sliding part in the direction of rotation of said developer carrying body comprises a thickness of said sliding part, and comprises a radius of said developer carrying body.