Linear Motion Door Mechanism for Nip Relaxation

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Solution Overview

Problem

Existing image forming apparatuses face challenges in efficiently clearing the nipping condition in the fixing unit, leading to sheet jam issues, as the existing mechanisms require significant space and complex mechanisms to relax the nipping pressure, making them bulky and difficult to manage.

Innovation Solution

The apparatus incorporates a linear motion member and guiding member configuration that allows for the nipping condition to be cleared through the opening motion of a door, using a coupler assembly and manipulation member to smoothly transition between nipping and relaxed conditions, reducing the size of the nip-relaxing mechanism and maintaining a compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional nip-relaxing mechanism with rotatable connector rod is used, then the nipping condition can be cleared when door is opened, but the mechanism requires significant internal space and has complex structure

Engineering Contradiction:
Improvenipping condition clearingVSAvoidinternal space requirement
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The mechanism is divided into separate functional components: the connector rod (220) that transmits motion, the nip-relaxing member (210) that applies force to separate the rollers, and the groove (211) that guides the connector rod's movement. This segmentation allows each component to be optimized independently and reduces the overall space required compared to a monolithic rotating mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of rotating the connector rod in an arc as in conventional designs, the connector rod moves linearly along a groove (211) formed in the nip-relaxing member (210). This inversion from rotational to linear motion eliminates the need for large internal space while still achieving the nipping condition clearing function when the door is opened.

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

2Strength

If a rigid shaft and groove configuration is used to bear nipping load, then structural strength is improved, but smooth movement becomes difficult to achieve

Engineering Contradiction:
Improvenipping load bearing capacityVSAvoidsmooth movement
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The groove (211) in the nip-relaxing member (210) is designed with specific geometric parameters that allow the shaft (212) to move smoothly while bearing nipping loads. The groove's shape and orientation are optimized to convert the linear motion into effective roller separation force, maintaining both strength and smooth operation.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the connector rod rotates in an arc to follow door opening motion, then the nipping condition is cleared effectively, but the mechanism becomes bulky and complex

Engineering Contradiction:
Improvenipping condition clearing effectivenessVSAvoidmechanism structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The conventional approach of rotating the connector rod in an arc is inverted to linear motion along a groove. This simplifies the mechanism structure by eliminating the need for complex rotational joints and arc-shaped paths, while still achieving effective nipping condition clearing through the linear displacement of the nip-relaxing member.

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

Solution Approach 2:

The groove (211) acts as an intermediary element that guides the connector rod (220) and translates the door opening motion into linear movement of the nip-relaxing member (210). This intermediary structure simplifies the overall mechanism by providing a straightforward motion path without requiring complex rotational components.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2444858B1Image forming apparatus
Publication Date: 2015.04.22 BROTHER KOGYO KK
  • EP2444858B1 patent drawingFigure 1
  • EP2444858B1 patent drawingFigure 2
  • EP2444858B1 patent drawingFigure 3

AI summary

An image forming apparatus (1) is provided. The image forming apparatus includes an image forming unit (20), a door (2) to cover an opening in a chassis (30), a fixing unit, a frame (100), a linear motion member to linearly move along with the door, a guiding member to guide the linear motion member to move linearly, a coupler assembly to couple the door with the linear motion member and move the linear motion member, and a manipulation member being movable according to movement of the linear motion member. The linear motion member includes a contact portion, with which the manipulation member comes in contact along an intersecting direction. The guiding member includes a slider plane to slidably support the linear motion member. The linear motion member is slidably supported by the slider plane of the guiding member at a surface which is on an opposite side from the surface having the contact portion.