Image forming apparatus and communication method
AssigneeCanon Kabushiki Kaisha
InventorHirotaka Seki
Life of this patent
Estimating the term…
Abstract
An image forming apparatus that executes processes necessary for image formation in a distributed manner. An image forming module (304) executes a process assigned by a sub master control unit (330) and a slave control unit (331) which are connected to each other by a pair of serial communication buses (380tx, 380rx). The sub master control unit (330) transmits first data for executing a process assigned to the slave control unit (331) via the serial communication bus (380tx). The slave control unit (331) transmits second data to the sub master control unit (330) via the serial communication bus (380rx) in a period during which the slave control unit (331) does not receive the first data.
Claims11
An image forming apparatus, comprising:
- a first control unit configured to transmit an instruction to a second control unit and receive a return which corresponds to the instruction from the second control unit;
- the second control unit that is connected to a load, and is configured to receive the instruction from the first control unit and control the load based on the instruction;
- a first communication line configured to transmit data from the first control unit to the second control unit;
- and
- a second communication line configured to transmit data from the second control unit to the first control unit,
- wherein the second control unit comprises:
- a holding unit configured to hold data;
- and
- a processor
- configured to transmit a return to the first control unit by using the second communication line when receiving the instruction from the first control unit via the first communication line,
- and configured to transmit the data held in the holding unit to the first control unit periodically based on a set period by using the second communication line when receiving the instruction to set to a specific mode from the first control unit via the first communication line, and
- wherein the processor, which is in the specific mode,
- is configured to determine at the timing for transmitting the data held in the holding unit based on the set period
- if it is determined that it is the timing for transmitting the data held in the holding unit,
- determine
- whether or not it is in a first state of the reception of the instruction from the first control unit via the first communication line and
- whether or not it is in a second state of the return to the first control unit using the second communication line
- and,
- if it is determined that it is neither in the first state nor in the second state, transmit the data held in the holding unit, and
- if it is determined that it is in the first state or in the second state, delay a timing for transmitting the data held in the holding unit so that the transmission of the data held in the holding unit is prevented from overlapping the transmission of the return.
A communication method to be executed by a second control unit, the second control unit being configured to communicate to a first control unit by using a first communication line that receives data from the first control unit and a second communication line that transmits data to the first control unit and thereby control a load based on an instruction from the first control unit,
- the communication method comprising:
- transmitting a return to the first control unit by using the second communication line when receiving the instruction from the first control unit via the first communication line;
- transmitting data to be held in a holding unit in the second control unit to the first control unit based on a set period via the second communication line when receiving the instruction to set to a specific mode from the first control unit via the first communication line;
- and;
- determining, in the specific mode, at the timing for transmitting the data held in the holding unit based on the set period,
- if it is determined that it is the timing for transmitting the data held in the holding unit,
- determining
- whether or not it is in a first state of the reception of the instruction from the first control unit via the first communication line and
- whether or not it is in a second state of the return to the first control unit using the second communication line
- and
- if it is determined that it is neither in the first state nor in the second state, transmitting the data held in the holding unit,
- if it is determined that it is in the first state or in the second state, delaying a timing for transmitting the data so that the transmission of the data held in the holding unit so that the transmission of the data held in the holding unit is prevented from overlapping the transmission of the return.
Dependencies are inferred from the claim text.