Communication method executed in image forming apparatus

An image forming apparatus comprising:

• an image forming unit configured to form an image on a sheet;
• a plurality of conveyance units, configured to convey the sheet to the image forming unit or convey the sheet passed through the image forming unit;
• a main control unit configured to control the image forming unit and the plurality of conveyance units in accordance with a conveyance position of the sheet;
• and
• a plurality of sub control units, each configured to control the image forming unit or one of the plurality of conveyance units on the basis of a communication signal received from the main control unit,
• wherein the communication signal transmitted to one of the plurality of sub control units includes:
• a first region storing information of a first communication type for a specific sub control unit among the plurality of sub control units, the specific sub control unit being a destination of the communication signal;
• and
• a second region storing information of a second communication type configured to be shared by the plurality of sub control units.

An image forming apparatus comprising:

• an image forming unit configured to form an image on a sheet;
• a plurality of conveyance units, configured to convey the sheet to the image forming unit or convey the sheet passed through the image forming unit;
• a main control unit configured to control the image forming unit and the plurality of conveyance units in accordance with a conveyance position of the sheet;
• and
• a plurality of sub control units, each configured to control the image forming unit or one of the plurality of conveyance units on the basis of a communication signal received from the main control unit,
• wherein the communication signal transmitted to one of the plurality of sub control units includes:
• a request region storing a request directed at a specific sub control unit among the plurality of sub control units;
• and
• a timing region storing at least one item of timing information indicating a control timing configured to be shared by the plurality of sub control units.

An image forming apparatus comprising:

• an image forming unit configured to form an image on a sheet;
• a plurality of conveyance units, configured to convey the sheet to the image forming unit or convey the sheet that has passed through the image forming unit;
• a main control unit configured to control the image forming unit and the plurality of conveyance units in accordance with a conveyance position of the sheet;
• and
• a plurality of sub control units, each configured to control the image forming unit or one of the plurality of conveyance units on the basis of a communication signal received from the main control unit,
• wherein the main control unit is configured to, over a communication line corresponding to a specific sub control unit among the plurality of sub control units, transmit a portion of a predetermined size of information of a first communication type for the specific sub control unit, then transmit information of a second communication type configured to be shared by the plurality of sub control units, and thereafter transmit a remaining portion of the information of the first communication type for the specific sub control unit.