Fixing Device Leaf Spring Tensile Force Transmission

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Solution Overview

Problem

Conventional thermal fixing devices face issues with accurately transmitting tensile force to a tubular member, leading to increased complexity, cost, and rotational torque due to the use of a movable wall and spring mechanism.

Innovation Solution

The implementation of leaf spring members that are in sliding contact with the inner peripheral surface of the fusing film, providing a stable and accurate tensile force by reducing the contact area and number of parts, allowing for balanced and efficient circular movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a movable wall and spring mechanism are used to provide tensile force to the tubular member, then the tensile force can be applied to prevent film slack, but the number of parts increases and the structure becomes complicated

Engineering Contradiction:
Improvetensile force applicationVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the movable wall component from the conventional structure. Instead of using a separate movable wall that requires a spring mechanism, the invention integrates the tensile force application directly through the guide member's elastic deformation, reducing the number of parts while maintaining the reliability of tensile force application to prevent film slack.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the functions of the movable wall and spring mechanism into a single integrated guide member structure. The guide member itself possesses elastic properties that enable it to provide tensile force without requiring separate spring components, thereby simplifying the overall structure while maintaining the necessary functional performance.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a movable wall and spring mechanism are used to provide tensile force to the tubular member, then the tensile force can be applied to prevent film slack, but the cost increases

Engineering Contradiction:
Improvetensile force applicationVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By extracting and removing the separate spring mechanism and movable wall components, the invention reduces the number of parts that need to be manufactured and assembled. This directly lowers manufacturing costs while maintaining the essential function of applying tensile force to the tubular member through the elastic deformation of the integrated guide member.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the movable wall is in surface contact with the inner peripheral surface of the tubular member, then the tensile force can be applied, but the contact surface increases and rotational torque increases

Engineering Contradiction:
Improvetensile force transmissionVSAvoidrotational torque
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention segments the contact interface between the guide member and tubular member from a continuous surface contact into a localized point or line contact. This segmentation reduces the contact surface area, thereby minimizing the friction and rotational torque generated while still maintaining effective tensile force transmission to the tubular member.

Inventive Principle:
Principle #1Segmentation

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 solution ensures accurate transmission of urging force to the fusing film, reducing the number of parts and contact surface, thereby lowering the rotational torque and enhancing the stability and assemblability of the fixing device.

Implementation Method 1

a pair of leaf spring members 190 which are in sliding contact with an inner peripheral surface of the fusing film 110 and which urge the inner peripheral surface of the fusing film 110 outward in a radial direction of the fusing film 110

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a halogen lamp 120 as a heat generator disposed in an internal space of the fusing film 110

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 3

a nipping portion 130 which nips the fusing film 110 in cooperation with a pressure roller 150 and which is arranged in the internal space of the fusing film 110... the nipping portion 130 is in sliding contact with an inner peripheral surface of the fusing film 110

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2469347B1Fixing device
Publication Date: 2020.05.06 BROTHER KOGYO KK
  • EP2469347B1 patent drawingFigure 1
  • EP2469347B1 patent drawingFigure 2
  • EP2469347B1 patent drawingFigure 3

AI summary

A fixing device (100) includes: a flexible tubular member (110), a nip member (130), a backup member (150), and a leaf spring member (190). The flexible tubular member (110) is circularly movable in a moving direction and has an inner peripheral surface. The nip member (130) is disposed so as to be in sliding contact with the inner surface of the tubular member. The backup member (150) is configured to provide a nip region in cooperation with the nip member (130) upon nipping the tubular member between the backup member and the nip member. The leaf spring member (190) is disposed so as to be in sliding contact with the inner peripheral surface of the tubular member and is configured to urge the inner peripheral surface of the tubular member outward in a radial direction of the tubular member.