Distributed Control Modules for Image Forming Apparatus

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Solution Overview

Problem

Image forming apparatuses using electrophotography face processing delays and complex wiring due to a single central processing unit handling multiple functions, leading to inefficient serial communication and potential jamming issues during sheet conveying.

Innovation Solution

A distributed control system using multiple control modules with peer-to-peer serial communication buses, where a master control unit coordinates sub-master and slave control units to ensure reliable data transmission and motor control through CRC verification and continuous read protocols.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single central processing unit controls all functions, then the control structure is simple, but the processing load increases and overall processing speed decreases

Engineering Contradiction:
Improvecontrol structureVSAvoidprocessing speed
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The control system is divided into multiple independent control modules, each with its own sub-CPU that handles specific functions. This segmentation distributes the processing load across multiple units, improving overall processing speed while maintaining manageable complexity through modular architecture.

Inventive Principle:
Principle #1Segmentation

2Reliability

If serial communication is used for data transmission between control modules, then data exchange is achieved, but communication delays occur when checking establishment and acquiring information regularly

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidcommunication delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by continuously monitoring communication status and pre-acquiring information before it is actually needed for control decisions. This allows the system to maintain communication reliability through proper establishment checks while reducing delays by having data ready in advance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sub-CPU continuously executes communication checks and information acquisition without interruption, ensuring that communication establishment is always verified and information is regularly updated. This continuous operation eliminates gaps in monitoring and reduces overall communication delays by maintaining constant data flow.

Inventive Principle:
Principle #20Continuity of useful action

3Manufacturing precision

If the motor speed is determined through serial communication, then proper speed control is achieved, but jamming may occur if communication is not established before motor rotation starts

Engineering Contradiction:
Improvemotor speed control precisionVSAvoidoperation reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The system applies preliminary anti-action by continuously verifying communication establishment and determining motor speed before the motor rotation actually begins. This preventive approach ensures that communication is fully established and speed parameters are correctly set, preventing jamming and operational failures before they can occur.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The control system performs preliminary determination of motor speed through serial communication before initiating motor rotation. By ensuring communication establishment and speed calculation are completed in advance, the system prevents operational errors and jamming while maintaining precise speed control.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If distributed control modules are used, then processing speed improves, but wiring arrangement becomes complicated

Engineering Contradiction:
Improveprocessing speedVSAvoidwiring arrangement
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Each control module is designed as a universal unit with integrated communication capabilities and standard interfaces. This multi-functionality allows modules to be interconnected using standardized wiring patterns, reducing overall wiring complexity despite the distributed architecture, while maintaining improved processing speed through parallel operation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2690503B1Image forming apparatus and communication method
Publication Date: 2020.07.08 CANON KK
  • EP2690503B1 patent drawingFigure 1
  • EP2690503B1 patent drawingFigure 2
  • EP2690503B1 patent drawingFigure 3

AI summary

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.