Developing Device Cartridge Mounting Mechanism

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Solution Overview

Problem

Existing image forming apparatuses face challenges in safely attaching and detaching developing cartridges without interference between the developing roller and photosensitive drum, leading to potential damage and increased apparatus size due to required clearance.

Innovation Solution

The design incorporates a mechanism where the developing cartridge is mounted and detached using a locking lever system that allows the developing roller to pivot between contact and separated positions relative to the photosensitive drum, utilizing guide rails and biasing members to manage the movement and prevent interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the developing cartridge is configured to be movable between contact and separated positions to prevent interference, then damage to developing roller and photosensitive drum is prevented, but the apparatus size increases due to required clearance space

Engineering Contradiction:
Improveprevention of damage to developing roller and photosensitive drumVSAvoidapparatus size
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The developing cartridge is designed with movable support members that allow the developing roller to dynamically change position between contact and separated states. The support members can pivot or translate to adjust the distance between the developing roller and photosensitive drum, enabling the system to adapt its configuration based on operational needs versus maintenance needs.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mechanism introduces movement in an additional dimension (radial or axial direction) beyond the normal rotational plane. By allowing the developing cartridge to move in a direction perpendicular to the drum surface, the system creates separation without requiring excessive lateral space, thus resolving the volume constraint while maintaining damage prevention.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If guide rails are made movable to enable developing cartridge attachment and detachment, then cartridge replacement is facilitated, but the position of mounting/dismounting becomes unstable causing interference and potential damage

Engineering Contradiction:
Improveattachment and detachment of developing cartridgeVSAvoidstability of mounting position
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Locking levers serve as intermediary elements that mediate between the developing cartridge and the guide rail system. These levers engage with corresponding locking surfaces to secure the cartridge at precise mounting positions, eliminating the instability caused by purely movable guide rails while maintaining ease of attachment and detachment.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system replaces a purely mechanical movable guide rail system with a hybrid system that incorporates locking mechanisms. The locking levers transform the continuously movable guide rail into a discretely positioned system with stable, predetermined mounting points, preventing interference while preserving operational ease.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3239782B1Developing device and image forming apparatus
Publication Date: 2019.08.21 CANON KK
  • EP3239782B1 patent drawingFigure 1
  • EP3239782B1 patent drawingFigure 2
  • EP3239782B1 patent drawingFigure 3

AI summary

An image forming apparatus (100) includes a first pressing member (80) pressing a unit (39) having a second rotating member (25) contactable with a first rotating member (1), and a supporting member (31) rotatably supporting the second rotating member (25). The first pressing member (80) moves the supporting member (31) and the second rotating member (25) moves from the contact position to the separated position. Also provided is a second pressing member (106) that presses the supporting member (31). The second pressing member (106) can move between a mounting/detaching restriction position restricting mounting/detaching of the cartridge (9), and a mounting/detaching allowing position allowing mounting/detaching of the cartridge (9). The second pressing member (106) moves the unit (39) to a position distanced from the first rotating member (1) by moving from the mounting/detaching restriction position to the mounting/detaching allowing position while pressing the supporting member (31).