Electrophotographic Drum Unit Coupling Member Dynamics

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Solution Overview

Problem

Existing electrophotographic photosensitive drum units face challenges in smooth mounting and dismounting, particularly when the main assembly lacks a mechanism for moving the coupling member, leading to potential misalignment and reduced rotational accuracy.

Innovation Solution

The electrophotographic photosensitive drum unit is designed with a coupling member that can pivot in various directions relative to the axis, allowing for smooth mounting and dismounting perpendicular to the driving shaft, and a regulating portion to manage inclination angles, ensuring accurate engagement and disengagement with the driving shaft.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the main assembly lacks a mechanism for moving the coupling member, then the device complexity is reduced, but the manufacturing precision and rotational accuracy deteriorate

Engineering Contradiction:
Improvedevice complexityVSAvoidrotational accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The coupling member is designed to be movable rather than fixed, allowing it to dynamically adjust its position and orientation during mounting and operation. This dynamic capability enables the coupling member to self-align with the driving shaft, achieving accurate engagement without requiring complex positioning mechanisms in the main assembly.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The coupling member incorporates self-aligning features that allow it to automatically position itself relative to the driving shaft during mounting. The movable design enables the coupling member to self-correct alignment deviations, eliminating the need for external adjustment mechanisms and maintaining rotational accuracy through self-service functionality.

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If the coupling member is fixed in position, then the manufacturing precision is improved, but the ease of operation for mounting and dismounting deteriorates

Engineering Contradiction:
Improveengagement accuracyVSAvoidmounting ease
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The coupling member transitions from a fixed to a movable design, enabling it to adjust its position during mounting operations. This dynamic capability allows the coupling member to accommodate alignment variations and engage smoothly with the driving shaft, significantly improving ease of operation while maintaining engagement accuracy through self-aligning features.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The movable coupling member is designed to preliminarily position itself before final engagement with the driving shaft. This preliminary self-positioning action facilitates easier mounting by reducing the precision required during the mounting operation, while still achieving accurate engagement in the final state.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the coupling member can pivot in various directions, then the ease of operation for mounting is improved, but the stability of the object's composition deteriorates

Engineering Contradiction:
Improvemounting easeVSAvoidstructural stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The coupling member is designed with controlled mobility, allowing it to pivot in specific directions during mounting to accommodate alignment variations. Once engaged with the driving shaft, the structure transitions to a stable locked position, maintaining structural integrity while providing operational flexibility during the mounting process.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The coupling member's movement capabilities are segmented into specific degrees of freedom, allowing pivoting in controlled directions during mounting while preventing unwanted movements during operation. This segmentation enables easy mounting through selective mobility while maintaining structural stability through constrained movement in critical directions.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2291714B1Process cartridge, electrophotographic image forming apparatus and electrographic photosensitive drum unit
Publication Date: 2016.06.29 CANON KK
  • EP2291714B1 patent drawingFigure 1~2
  • EP2291714B1 patent drawingFigure 3(a)~3(b)
  • EP2291714B1 patent drawingFigure 4~5

AI summary

A process cartridge which is detachably mountable to a main assembly of an electrophotographic image forming apparatus including a driving shaft (180) having a rotational force applying portion by moving in a direction substantially perpendicular to an axis of the driving shaft, includes i) an electrophotographic photosensitive drum rotatable about an axis; ii) a coupling. member engageable with the rotational force applying portion to receive a rotational force for rotating the drum, the coupling member being capable of taking a rotational force transmitting angular position for transmitting the rotational force, a pre-engagement angular position in which the coupling member is inclined away from the axis and a disengaging angular position in which the coupling member is inclined away from the axis and iii) a regulating portion (170) for regulating an inclination angle of the coupling member such that downward inclination angle of the coupling member is smaller than an inclination angle of the coupling member when the coupling member is at the pre-engagement angular position, wherein in mounting the cartridge to the main assembly, the coupling member moves from the pre-engagement angular position to the rotational force transmitting angular position, and in dismounting the cartridge from the main assembly, the coupling member moves from the rotational force transmitting angular position to the disengaging angular position to disengage from the driving shaft.