Image forming apparatus implemented by a distributed control system

An image forming apparatus comprising:

• an upper layer control unit that controls the image forming apparatus which forms an image on a printing material;
• and
• first and second lower layer control units that are controlled by said upper layer control unit and respectively control first and second processing units for performing image formation,
• wherein said upper layer control unit is connected to said first and second lower layer control units by communication bus with a first communication speed, and
• said first lower layer control unit is connected to said first processing unit by a first serial communication line in a one-to-one manner having a communication speed higher than the first communication speed, and said second lower layer control unit is connected to said second processing unit by a second serial communication line in a one-to-one manner having a communication speed higher than the first communication speed, and
• said first lower layer control unit controls a feed function of feeding a printing material and said second lower layer control unit controls an image formation function of forming an image on a printing material.