Photosensitive Drum Coupling Mechanism for Stable Torque Transmission

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Solution Overview

Problem

Existing electrophotographic image forming apparatuses face challenges in maintaining stable torque transmission to cartridges, which can affect the reliability and efficiency of image formation.

Innovation Solution

A drum unit and cartridge design that includes a drum coupling mechanism to stabilize the rotation of the photosensitive drum, ensuring consistent torque transmission and improved maintainability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a coupling structure is used to transmit driving force from the main assembly to the cartridge, then the cartridge can be driven for image formation, but the torque transmission becomes unstable affecting reliability

Engineering Contradiction:
Improvetorque transmission stabilityVSAvoidcoupling structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The coupling structure incorporates a movable supporting portion that can dynamically adjust its position to accommodate variations in torque requirements. The driving force receiving portion is designed to move relative to the coupling member, enabling the system to adapt to changing operational conditions and maintain stable torque transmission throughout the cartridge's lifecycle.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The coupling mechanism allows for changes in the physical parameters of torque transmission by enabling movement between the driving force receiving portion and the photosensitive drum. This movement capability permits the system to adjust torque delivery parameters dynamically, ensuring consistent performance despite variations in cartridge wear or operational demands.

Inventive Principle:
Principle #35Parameter changes

2Ease of repair

If the cartridge structure is designed to be dismountable for user maintenance, then maintainability improves, but the torque transmission stability may be compromised

Engineering Contradiction:
Improveuser maintainabilityVSAvoidtorque transmission consistency
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

The cartridge is divided into separable components including the drum unit and process cartridge, allowing users to easily remove and replace consumable parts for maintenance. Despite this segmentation, the coupling structure maintains reliable torque transmission through its movable supporting portion that ensures proper engagement and force transmission even after user maintenance operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cartridge is designed to enable user self-maintenance through easy dismounting and remounting. The coupling structure accommodates repeated user operations while maintaining torque transmission stability, allowing users to perform maintenance without compromising the reliability of the driving force transmission.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If the photosensitive drum rotation is stabilized by increasing torque, then rotation stability improves, but the torque requirements increase affecting energy consumption

Engineering Contradiction:
Improvephotosensitive drum rotation stabilityVSAvoidenergy consumption for drum rotation
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The movable supporting portion acts as an intermediary between the coupling structure and the photosensitive drum, optimizing the transmission of torque. This intermediary mechanism ensures stable drum rotation by smoothly transmitting driving force while minimizing energy losses, achieving rotation stability without excessive energy consumption.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The dynamic movement capability of the supporting portion allows the system to optimize torque transmission in real-time, providing just enough torque to maintain stable rotation without over-consuming energy. The system adapts its torque delivery to match actual operational needs, improving energy efficiency while maintaining rotation stability.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4202557B1Cartridge, drum unit and image forming apparatus
Publication Date: 2025.08.13 CANON KK
  • EP4202557B1 patent drawingFigure 1(a)~1(b)
  • EP4202557B1 patent drawingFigure 2
  • EP4202557B1 patent drawingFigure 3

AI summary

[TASK] To further develop prior art technique. [SOLUTION] A cartridge includes a photosensitive drum and a coupling. the coupling includes a main body and a movable member movable relative to the main body. The movable member includes an engaging portion which is capable of entering between a driving force application member and a braking force application member by the movement relative to the main body. The movable member receives a driving force for rotating the photosensitive drum, from the driving force application member and also receives a braking force applying a load against rotation of the photosensitive drum, from the braking force application member.