Switching Member Guides Cartridge Replacement in Image Forming Apparatus

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Solution Overview

Problem

The existing image forming apparatuses using electrophotographic methods face usability issues during cartridge replacement, leading to potential damage of cartridges and image defects due to improper handling and simultaneous removal or insertion of drum and developing units.

Innovation Solution

The implementation of a switching member, such as the CRG lever, which selectively allows the detachment and attachment of either the developing unit or the drum unit, preventing simultaneous operation and guiding the user to ensure proper handling, thereby reducing the risk of damage and improving usability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the drum unit and developing unit are independently replaceable, then maintenance flexibility is improved, but the risk of simultaneous improper handling and damage increases

Engineering Contradiction:
Improvemaintenance flexibilityVSAvoidcartridge damage risk
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

A guide member is introduced as an intermediary component between the drum unit and developing unit. This guide member includes a guide portion that physically guides the developing unit during insertion, ensuring it is inserted at the proper position and orientation. The guide member prevents simultaneous improper handling by providing mechanical guidance and restriction, thereby reducing the risk of damage while maintaining independent replaceability of both units

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If both drum unit and developing unit can be removed simultaneously, then replacement efficiency is improved, but handling safety deteriorates

Engineering Contradiction:
Improvereplacement efficiencyVSAvoidhandling safety
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The guide member is pre-installed in the apparatus before the developing unit is inserted. The guide portion of the guide member is positioned in advance to receive and guide the developing unit during insertion. This preliminary positioning ensures that even when both units are removed simultaneously for efficiency, the developing unit will be properly guided during reinsertion, maintaining handling safety

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the developing unit has movable contact with the photosensitive drum, then image quality is improved, but the complexity of proper insertion increases

Engineering Contradiction:
Improveimage qualityVSAvoidinsertion complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The guide member acts as an intermediary that simplifies the insertion process for the developing unit. By providing a physical guide portion that aligns with the insertion direction, the guide member reduces the complexity of proper insertion. This allows the developing unit to be easily inserted at the correct position and orientation, enabling the movable contact configuration with the photosensitive drum to be properly implemented without increasing user complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3584639B1Image forming apparatus
Publication Date: 2024.06.26 CANON KK
  • EP3584639B1 patent drawingFigure 1A~1B
  • EP3584639B1 patent drawingFigure 2
  • EP3584639B1 patent drawingFigure 3A~3D

AI summary

An image forming apparatus (100) comprises a drum unit (5) including a photosensitive drum (1) configured to bear a toner image; a developing unit (4) including a developing roller (24) configured to supply toner to the photosensitive drum (1); an apparatus main body having a mounting space to which the drum unit (5) and the developing unit (4) are independently and detachably attached in an insertion and removal direction; and a switching member (36) configured to be movable, with respect to the drum unit (5) and the developing unit (4), between a first position and a second position, the first position being a position where the switching member (36) is overlapped with the drum unit (5) and is not overlapped with the developing unit (4) when viewed in the insertion and removal direction, the second position being a position where the switching member (36) is overlapped with the developing unit (4) and is not overlapped with the drum unit (5) when viewed in the insertion and removal direction.