Drive-side Drum Flange Rigidity via Recessed Portions

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Solution Overview

Problem

The flange member in electrophotographic photosensitive drum units has low rigidity, leading to deformation under driving force, which affects the rotational speed of the drum and subsequently the image quality formed by the image forming apparatus.

Innovation Solution

The drive-side drum flange is designed with a specific configuration, including cylindrical portions and recessed portions, to enhance rigidity and stability, preventing deformation and maintaining consistent rotational speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the flange member has low rigidity, then the device complexity is reduced and manufacturing is easier, but the flange member rotates in a deformed state under driving force, causing change in rotational speed and decreasing image quality

Engineering Contradiction:
Improverigidity of flange memberVSAvoidstructural complexity of flange member
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The flange member is divided into multiple functional portions: a first cylindrical portion for bearing support, a second cylindrical portion for drum connection, and multiple recessed portions for reinforcement. This segmentation allows each portion to be optimized independently for its specific function while collectively achieving high rigidity without excessive overall complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Recessed portions are strategically positioned at specific locations on the flange member where structural reinforcement is most needed. These localized features provide targeted rigidity enhancement at critical stress points without requiring uniform thickening of the entire flange structure, thus improving rigidity efficiently while controlling manufacturing complexity

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the flange member deforms under driving force, then the structure becomes simpler, but the rotational speed of the drum changes, decreasing the manufacturing precision and image quality

Engineering Contradiction:
Improverotational speed consistencyVSAvoidrigidity of flange member
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The recessed portions are pre-formed during manufacturing to provide structural reinforcement before the flange member is installed and subjected to driving forces. This preliminary structural preparation ensures that when the drum rotates, the flange member maintains its shape and prevents deformation, thereby maintaining consistent rotational speed and high manufacturing precision

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If the flange member is made more rigid, then the rotational speed stability is improved, but the manufacturing complexity and difficulty increase

Engineering Contradiction:
Improverotational speed stabilityVSAvoidmanufacturing ease of flange member
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The rigidity of the flange member is enhanced by changing its geometric parameters - specifically by adding recessed portions with optimized dimensions and positions. This allows achievement of high rotational speed stability through dimensional optimization rather than material changes or complex assembly structures, thereby maintaining ease of manufacture while improving performance

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3156848B1Electrophotographic photosensitive drum unit, cartridge, and flange member
Publication Date: 2021.12.08 CANON KK
  • EP3156848B1 patent drawingFigure 1A~1C
  • EP3156848B1 patent drawingFigure 2
  • EP3156848B1 patent drawingFigure 3

AI summary

A flange member (63) includes a first cylindrical portion (63a), a second cylindrical portion (63b) disposed inside the first cylindrical portion (63a) coaxially with the first cylindrical portion (63a), an inwardly protruding portion (63e) protruding from an inner circumference of the second cylindrical portion (63b), a first wall (63f1), a second wall (63f2) opposed to the first wall (63f1), and a connecting portion (63f3). The first wall (63f1) connects the first cylindrical portion (63a) and the second cylindrical portion (63b) and is in contact with a shaft member (75) between the first wall (63f1) and the second wall (63f2) to receive a driving force. The connecting portion (63f3) connects the first cylindrical portion (63a) and the second cylindrical portion (63b) and connects the first wall (63f1) and the second wall (63f2). A groove (63g) is provided inside the first cylindrical portion (63a) and outside the second cylindrical portion (63b).