Fixing Device Shutter Pivot Axis Downstream Nipping Region

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Solution Overview

Problem

Conventional fixing devices require a larger pivotally moving amount for the shutter and can make image forming apparatuses bulky due to the placement of pivot axes, especially when a nipping pressure changing mechanism is included.

Innovation Solution

A fixing device with a shutter that pivots about a first axis positioned downstream of the nipping region, coinciding with the pivot axis of a cam for nipping pressure change, reducing the need for additional mechanical components and allowing a more compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the pivot axis is positioned in the vicinity of the sheet inlet, then the shutter can close the inlet effectively, but the shutter requires a relatively larger pivotally moving amount to open and close the inlet

Engineering Contradiction:

Improveshutter closing effectivenessVSAvoidpivotally moving amount of shutter

Core Design Contradiction:

Ease of operationVSLength of moving object

Solution Approach 1:

The pivot axis is repositioned from the conventional location near the sheet inlet to a new location downstream of the nipping region. This spatial relocation in the conveying direction allows the shutter to achieve effective closing while reducing the required angular movement for operation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If the pivot axis of the cam is arranged at a different position from the pivot axis of the shutter, then the nipping pressure changing mechanism can function independently, but the image forming apparatus becomes bulky

Engineering Contradiction:

Improveindependent mechanism functionVSAvoidapparatus size

Core Design Contradiction:

Adaptability or versatilityVSVolume of stationary object

Solution Approach 1:

The pivot axis of the shutter and the pivot axis of the cam are arranged to coincide with each other. This merging of pivot axes allows both the shutter mechanism and the nipping pressure changing mechanism to share a common rotational center, eliminating the need for separate pivot support structures and reducing the overall apparatus volume.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The common pivot axis structure serves dual functions: it acts as the rotation center for the shutter while simultaneously serving as the rotation center for the cam. This multi-functional design eliminates redundant mechanical components and reduces apparatus size.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12085887B2Fixing device including shutter pivotable about axis positioned downstream of nipping region in sheet conveying direction

Publication Date: 2024.09.10 BROTHER KOGYO KK

AI summary

A fixing device includes a first rotatable body, a second rotatable body, a frame, and a shutter. The frame supports the first rotatable body and the second rotatable body. The first rotatable body and the second rotatable body provide a nipping region therebetween where a sheet is configured to be conveyed in a conveying direction. The sheet is configured to pass through an opening of the frame to be conveyed toward the nipping region. The shutter is pivotally movable about a first axis between a closed position where the shutter closes the opening and an open position where the shutter opens the opening. The first axis is positioned downstream of the nipping region in the conveying direction.