Patent ID: 6650858
Filing Date: 2003-11-18
Classification: G03G

Abstract:
A developing apparatus comprising:first developing means for developing a latent image formed on an image bearing member with a first developer comprising a magnetic toner, said first developing means including a first developer carrying member for carrying and feeding the first developer to the image bearing member and first magnetic field generating means disposed in said first developer carrying member; and second developing means for developing a latent image formed on the image bearing member with a second developer comprising a magnetic carrier and a non-magnetic toner while the second developer contacts the image bearing member, said second developing means including a second developer carrying member for carrying and feeding the second developer to the image bearing member and second magnetic field generating means disposed in said second developer carrying member, wherein a magnetization intensity M&sgr; (Am2/kg) of the magnetic toner in an external magnetic field of 795.8 (kA/m) and a magnetization intensity C&sgr; (Am2/kg) of the magnetic carrier in the same external magnetic field, satisfy the following inequalities: 35<C&sgr;(Am2/kg)<M&sgr;(Am2/kg)Ã—1.7.