Flange Member Stress-Absorbing Linking Portion for Photosensitive Drum

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Solution Overview

Problem

The existing flange members in photosensitive drums for electrophotography devices face challenges in maintaining high runout accuracy due to deformation and displacement of axle openings during press fitting, leading to issues with smooth rotation and image quality, particularly in full-color printing applications.

Innovation Solution

A flange member design incorporating stress-absorbing openings in the linking portion to absorb stress and prevent deformation of the axle opening, ensuring accurate alignment and secure attachment to the sleeve member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the flange member is press-fitted to the sleeve member to ensure secure attachment, then the attachment strength is improved, but the axle opening deforms or displaces due to stress transmission, worsening the runout accuracy

Engineering Contradiction:
Improveattachment strengthVSAvoidrunout accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent introduces a stress-absorbing portion (ridges or recesses) in the linking portion of the flange member that acts as a cushioning element before stress reaches the axle opening. This beforehand cushioning absorbs the stress generated during press-fitting, preventing stress transmission to the axle opening and thus avoiding deformation or displacement that would worsen runout accuracy, while still maintaining secure attachment through the press-fit connection

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Stability of the object's composition

If the flange member has high rigidity to maintain structural stability, then the structural stability is improved, but the stress cannot be absorbed during press fitting, worsening the deformation of the axle opening

Engineering Contradiction:
Improvestructural stabilityVSAvoidaxle opening position accuracy
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating a stress-absorbing portion with specific local structural features (ridges or recesses) in the linking portion of the flange member. This local modification provides stress-absorbing capability exactly where needed during press-fitting, while the rest of the flange member maintains its overall rigidity and structural stability. The localized stress-absorbing structure prevents axle opening deformation without compromising the global structural integrity of the flange member

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the linking portion is made thin to reduce material usage, then the ease of manufacture is improved, but the stress transmission causes deformation, worsening the runout accuracy

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidaxle opening alignment
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent incorporates a stress-absorbing portion (ridges or recesses) in the linking portion that provides beforehand cushioning against stress during press-fitting. This allows the linking portion to be manufactured with simpler, thinner structures while still protecting the axle opening from stress-induced deformation. The cushioning effect compensates for the reduced structural capacity of thinner linking portions, maintaining axle opening alignment accuracy without complicating the manufacturing process

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The proposed flange member effectively reduces deformation and displacement of the axle opening, enhancing runout accuracy and maintaining image quality by absorbing stress, thus improving the reliability of the photosensitive drum's rotation and image formation process.

Implementation Method 1

the linking portion includes a stress-absorbing opening when the press-fitted portion is press-fitted in the end-opening portion, the stress transmitted from the press-fitted portion via the linking portion to the axle opening portion is absorbed by the stress-absorbing opening

Methodology Applied
Scientific EffectStress absorption: Stress Relaxation

Data Source

PatentEP2638434B1Flange member, photosensitive drum, process cartridge, image forming apparatus, and image forming method
Publication Date: 2021.03.24 RICOH CO LTD
  • EP2638434B1 patent drawingFigure 1A
  • EP2638434B1 patent drawingFigure 1B
  • EP2638434B1 patent drawingFigure 2

AI summary

A disclosed flange member includes a press-fitted portion to be press-fitted in an axial end-opening portion of a hollow and cylindrical sleeve member; an axle opening portion including an axle opening into which a shaft member is inserted when the press-fitted portion is press-fitted in the end-opening portion; and a linking portion extending in a direction parallel to a circular cross section of the sleeve member and connecting the axle opening portion to the press-fitted portion. The linking portion includes a stress-absorbing portion that is deformed so as to absorb stress to which an outer peripheral surface of the press-fitted portion is subjected upon contact with an inner peripheral surface of the sleeve member when the press-fitted portion is press-fitted in the end-opening portion, thus preventing the stress from being transmitted to the axle opening portion via the linking portion.