Developing Device Lock Mechanism for Stable Process Unit Pull-Out

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Solution Overview

Problem

The existing image forming apparatuses face instability during maintenance or replacement of process units due to the shift in center of gravity when the process unit is pulled out, and the application of downward force to lock the developing devices further destabilizes the system.

Innovation Solution

The image forming apparatus incorporates a pair of side plates with lock members and a biasing mechanism, allowing the lock members to move between lock and unlock positions via a guide part during the pull-out operation, ensuring stable attachment and detachment of developing devices without applying a downward force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the process unit is pulled out from the apparatus main body for maintenance or replacement, then the developing devices can be accessed and replaced, but the center of gravity shifts causing the image forming apparatus to become unstable

Engineering Contradiction:
Improveaccess to developing devicesVSAvoidapparatus stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The locking mechanism is segmented into multiple lock members, each independently controllable for each developing device. This allows selective locking/unlocking of individual devices while the process unit remains pulled out, maintaining stability without requiring full retraction

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lock members are made movable between locked and unlocked states through the guide part mechanism. This dynamic capability allows the system to adapt its locking state based on whether the process unit is inserted or pulled out, maintaining stability in both configurations

Inventive Principle:
Principle #15Dynamics

2Reliability

If the developing device is pushed downward to retract the lock member for attachment, then the developing device can be locked to the side plate, but a downward force is applied to the process unit increasing instability

Engineering Contradiction:
Improvelocking reliabilityVSAvoidprocess unit stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

Instead of pushing the developing device downward to retract the lock member, the guide part protrusion is used to push the lock member outward during pull-out. This reverses the force direction, eliminating the destabilizing downward force while achieving reliable locking

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The guide part acts as an intermediary element between the process unit and the lock member. It transmits the pull-out motion to automatically retract the lock member without requiring direct downward force on the developing device, reducing instability

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This configuration maintains stability during process unit operations by automatically adjusting lock positions, facilitating easy and stable attachment and detachment of developing devices without additional manual effort, thus stabilizing the apparatus even when the center of gravity shifts.

Implementation Method 1

a biasing member (95) which biases the lock member (71) to the lock position

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

a guide part (135) which guides one of the lock members (71) from the lock position to the unlock position with a pull-out operation of the process unit (25)

Methodology Applied
Scientific EffectMechanical guidance: Guided Rotor Compressor

Data Source

PatentEP4586022B1Image forming apparatus
Publication Date: 2025.11.12 KYOCERA DOCUMENT SOLUTIONS INC
  • EP4586022B1 patent drawingFigure 1
  • EP4586022B1 patent drawingFigure 2
  • EP4586022B1 patent drawingFigure 3

AI summary

An image forming apparatus (1) includes a process unit (25) pulled out from an apparatus main body (3) along a pull-out direction. The process unit (25) includes a pair of side plates (61L, 61R), a plurality of developing devices (35), a lock member (71), and a biasing member (95). The side plates (61L, 61R) face each other in a direction crossing the pull-out direction. The developing devices (35) are arranged along the pull-out direction and attached to the side plates (61L, 61R) detachably. The lock member (71) is provided for each developing device (35) and movable between a lock position and an unlock position. The biasing member (95) biases the lock member (71) to the lock position. The apparatus main body (3) includes a guide part (135). As the process unit (25) is pulled out, one of the lock members (71) is guided by the guide part (135) and moved to the lock position or the unlock position such that the developing device (35) corresponding to the lock member (71) is locked or unlocked.