Developing apparatus and image forming apparatus

An image forming apparatus comprising:

• a rotatable image bearing member;
• a first rotatable developer carrying member, disposed so as to be opposed to said image bearing member, for carrying a magnetic one component developer to a first developing position to develop a latent image on said image bearing member;
• a second rotatable developer carrying member, disposed so as to be opposed to said image bearing member at a position downstream of said first developer carrying member with respect to a rotational direction of said image bearing member, for carrying the magnetic one component developer to a second developing position to develop a latent image on said image bearing member, wherein said second developer carrying member is rotatable in the same direction as a rotational direction of said first developer carrying member;
• a first magnetic member provided in said first developer carrying member and having a plurality of magnetic poles;
• and
• a second magnetic member provided in said second developer carrying member and having a plurality of magnetic poles,
• wherein said magnetic poles of said first magnetic member includes:
• a first magnetic pole which is closest to said image bearing member,
• a second magnetic pole having the same polarity as said first magnetic pole and disposed at a position which is adjacent to a closest position where said first developer carrying member and said second developer carrying member are closest to each other and which is downstream of the closest position with respect to the rotational direction of said first developer carrying member, and
• a third magnetic pole having a magnetic polarity different from that of said first magnetic pole and disposed upstream of said second magnetic pole and downstream of said first magnetic pole with respect to the rotational direction of said first developer carrying member,
• wherein said magnetic poles of said second magnetic member include:
• a fourth magnetic pole which is closest to said image bearing member and which has the same polarity as said first magnetic pole;
• and
• a fifth magnetic pole which has a polarity different from that of said second magnetic pole which is disposed at a position opposed to said second magnetic pole adjacent to and upstream of said fourth magnetic pole with respect to the rotational direction of said second developer carrying member.