Drawer Unit Locking Mechanism for Image Forming Apparatus

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Solution Overview

Problem

Existing drawer units for image forming apparatuses require high drawing forces, making it burdensome for users, especially powerless individuals, and previous solutions either combine drawers or rely on insufficient spring resilience, which are not effective for reducing the necessary force.

Innovation Solution

A drawer unit with a locking mechanism that utilizes a rotating shaft and locking member, where the operating handle rotates to engage and disengage the locking member with a lock receiver, reducing the force required for drawing by allowing the locking member to be pushed by a pushing wall, thereby reducing resistance and facilitating easier insertion and removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking mechanism is used to secure the drawer, then the drawer can be firmly held in place, but the drawing force required to remove the drawer increases

Engineering Contradiction:
Improvelocking reliabilityVSAvoiddrawing force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The push-lock mechanism performs preliminary unlocking action before the drawer is fully drawn. When the drawer is pushed during insertion, the pushing wall automatically unlocks the locking member in advance, so that the locking engagement is released before the drawer needs to be pulled out, reducing the force required for removal.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pushing wall acts as an intermediary element that transfers the pushing force to unlock the locking member. Instead of directly pulling the drawer against the locking force, the user pushes the drawer, and the pushing wall mediates this action to disengage the locking mechanism, converting a high-force pulling action into a low-force pushing action.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a spring-based push-lock mechanism is used, then the drawer can be automatically pushed when unlocked, but the spring resilience is insufficient to reduce the drawing force for image forming apparatus drawers

Engineering Contradiction:
Improveautomatic pushingVSAvoiddrawing force reduction
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The invention extracts the automatic pushing function from the spring mechanism and separates it from the locking function. The spring provides only the minimal force needed to unlock the push-lock mechanism, while the actual pushing force is generated by the user's manual push action transmitted through the pushing wall, compensating for the insufficient spring resilience.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system transitions from a static spring-based pushing mechanism to a dynamic user-driven pushing mechanism. The pushing wall enables the drawer to be pushed dynamically by user action rather than relying solely on static spring force, allowing the system to adapt to the higher force requirements of image forming apparatus drawers.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the locking member is engaged with the lock receiver, then the drawer is securely locked, but resistance to drawing increases

Engineering Contradiction:
Improvelocking securityVSAvoidresistance to drawing
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The pushing wall applies preliminary anti-action to the locking member by pushing it in the unlocking direction before the drawer is drawn. This preliminary action counteracts the locking engagement, reducing the resistance that would otherwise be encountered when trying to pull the drawer out while locked.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP3051363B1Drawer unit, and image forming apparatus using the drawer unit
Publication Date: 2018.09.19 RICOH CO LTD
  • EP3051363B1 patent drawingFigure 1
  • EP3051363B1 patent drawingFigure 2~3
  • EP3051363B1 patent drawingFigure 4

AI summary

A drawer unit including a housing and a drawer inserted into the housing in inserting direction and drawn therefrom in drawing direction is provided. A locking member is mounted on the housing or the drawer to extend in direction intersecting the inserting direction, and is rotatable on a rotating shaft extending in the inserting direction such that when the drawer is inserted, the locking member rotates from unlock position to lock position in locking direction while rotating from the lock position to the unlock position in unlocking direction prior to drawing of the drawer. A locking wall and a pushing wall are mounted on the other of the housing and the drawer. The locking member in the lock position is engaged with the locking wall. When being rotated in the unlocking direction, the locking member is contacted with the pushing wall, which pushes the drawer in the drawing direction.