Developing device having regulating rotary member for regulating toner amount

Abstract

A developing device for an image forming apparatus such as a copying machine, a printer, or the like to develop an electrostatic latent image on an image carrier includes a toner carrier which moves while carrying a toner on its surface, and a regulating member for regulating the amount of toner on the toner carrier by applying a moving force to the toner in a direction opposite to the moving direction of the toner carrier. In a regulating portion defined by the regulating member, a convey force received by a toner portion, which does not contact the surface of the toner carrier, from the regulating member is larger than a convey force received from the toner carrier.

What is claimed is:  
     
       1. A developing device comprising: 
       a toner carrier, having a magnet therein, for carrying a magnetic toner;  
       a regulating rotary member, having a magnet therein, for regulating an amount of toner on said toner carrier, said regulating rotary member being provided to be spaced apart from the surface of said toner carrier by a predetermined distance; and  
       magnetic field generating means for applying a magnetic force to said regulating rotary member from a side of said regulating rotary member opposite said toner carrier, said magnetic field generating means applying the magnetic force in a direction substantially opposite to a direction of a magnetic force received by said regulating rotary member from the magnet in said toner carrier.  
     
     
       2. A device according to  claim 1 , wherein said magnetic field generating means comprises a magnet which is arranged at a substantially central portion, in an axial direction, of said regulating rotary member. 
     
     
       3. A device according to  claim 1 , wherein a magnetic flux density of the magnetic force applied by said magnetic field generating means increases in a direction from said toner carrier toward said regulating rotary member. 
     
     
       4. A device according to  claim 1 , wherein, in a regulating portion of said regulating rotary member, a rotational direction of said regulating rotary member is opposite to a moving direction of said toner carrier.