Image Forming Device Lock Member Positioning Mechanism

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Solution Overview

Problem

Conventional image forming devices experience frictional wear in positioning parts due to repeated attachment and detachment of the image forming unit, leading to degradation in positioning accuracy.

Innovation Solution

The design incorporates a support shaft with cutout parts and a reference shaft, along with a lock member having inclined surfaces, which guides the image forming unit into position without direct contact, reducing frictional wear and maintaining accurate positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the shaft directly abuts against the hole for positioning the image forming unit, then the positioning structure is simple and easy to manufacture, but repeated attachment and detachment cause frictional wear that degrades positioning accuracy

Engineering Contradiction:
Improvepositioning accuracyVSAvoidpositioning structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary mechanism (inclined surface and positioning surface structure) between the shaft and hole to prevent direct abutment. The image forming unit is guided onto the shaft via an inclined surface that engages with a positioning surface, eliminating direct contact between the shaft and hole during attachment/detachment operations, thereby reducing frictional wear while maintaining positioning accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The positioning function is segmented into multiple components: the shaft, the inclined surface, and the positioning surface. This segmentation allows each component to perform a specific function - the shaft provides the positioning reference, the inclined surface guides the attachment motion, and the positioning surface receives the shaft without direct hole-shaft contact, thus resolving the contradiction between simplicity and wear resistance

Inventive Principle:
Principle #1Segmentation

2Ease of repair

If the image forming unit is frequently attached and detached for maintenance, then maintenance efficiency is improved, but frictional wear of positioning parts increases leading to degraded positioning accuracy

Engineering Contradiction:
Improvemaintenance efficiencyVSAvoidpositioning accuracy
Core Design Contradiction:
Ease of repairVSManufacturing precision

Solution Approach 1:

The patent applies beforehand cushioning by designing the inclined surface and positioning surface to prevent direct contact between the shaft and hole from the outset. This preventive design cushioning against frictional wear that would otherwise accumulate with repeated maintenance operations, ensuring positioning accuracy is maintained over time despite frequent attachment and detachment cycles

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

Data Source

PatentEP2136269B1Image forming device
Publication Date: 2012.11.21 BROTHER KOGYO KK
  • EP2136269B1 patent drawingFigure 1(A)~1(B)
  • EP2136269B1 patent drawingFigure 2(A)~2(B)
  • EP2136269B1 patent drawingFigure 3

AI summary

An image forming device having a frame (200), a door (400), and a movable image forming unit (350) to be assembled in the frame when the door is open. The image forming unit has a support shaft (352), and frame has a hole (211) on which the support shaft abuts for positioning of the image forming unit relative to the frame when the door is closed. A lock unit (500) formed with a recessed portion is movable in association with the movement of the door. When the door is open, the lock unit is at its abutment position so that the support shaft abuts the recessed portion. When the door is closed the lock unit is moved so that the support shaft is brought into abutment with the hole.