Fixing Device Vapor Chamber Protrusions for Thermal Efficiency

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Solution Overview

Problem

Existing fixing devices with vapor chambers suffer from reduced thermal efficiency due to heat transfer from the fixing member to the holding member, leading to temperature deviations and inefficiencies.

Innovation Solution

A fixing device design that includes a fixing member, pressure rotator, and nip forming member with a vapor chamber and holding member, where the holding member features protrusions to reduce heat transfer and enhance thermal efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a vapor chamber is used to maintain thermal uniformity in the fixing member, then temperature distribution is improved, but heat is transferred to the holding member through the vapor chamber, deteriorating thermal efficiency

Engineering Contradiction:
Improvetemperature uniformityVSAvoidthermal efficiency
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The holding member is segmented into multiple protrusions that contact the vapor chamber at discrete points rather than a continuous surface. This segmentation reduces the total contact area between the holding member and vapor chamber, thereby minimizing heat transfer to the holding member while maintaining structural support and thermal uniformity benefits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The contact interface between the holding member and vapor chamber is made non-uniform through the protrusion structure. Different regions have different contact characteristics - the protrusions provide localized contact points that reduce overall heat transfer area while maintaining necessary mechanical support. This creates local variations in thermal conductivity that prevent excessive heat loss.

Inventive Principle:
Principle #3Local quality

2Temperature

If a hollow vapor chamber is used for heat transfer, then thermal uniformity is improved, but the structure has reduced strength

Engineering Contradiction:
Improvethermal uniformityVSAvoidstructural strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The holding member is divided into multiple protrusions that contact the vapor chamber at discrete locations. This segmented structure provides mechanical support at multiple points, strengthening the overall assembly while maintaining the hollow vapor chamber structure for thermal uniformity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fixing device uses a composite structure combining the hollow vapor chamber (for thermal management) with the protrusion-type holding member (for mechanical support). This composite design integrates the thermal benefits of the hollow chamber with the structural strength of the reinforced holding member.

Inventive Principle:
Principle #40Composite materials

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

The design inhibits heat transfer from the fixing member to the holding member, maintaining thermal uniformity and improving overall thermal efficiency of the fixing device.

Implementation Method 1

Heat is transferred from an inner circumferential face of the fixing member to the vapor chamber

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a vapor chamber including a columnar member for reinforcement inside its hollow has been known as an alternative technique to such a heat pipe

Methodology Applied
Scientific EffectVapor chamber thermal conduction: Heat Pipe

Implementation Method 3

The holding member holds the vapor chamber and includes a plurality of protrusions in contact with the vapor chamber

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4632494A1Fixing device and image forming apparatus
Publication Date: 2025.10.15 RICOH CO LTD
  • EP4632494A1 patent drawingFigure 1
  • EP4632494A1 patent drawingFigure 2
  • EP4632494A1 patent drawingFigure 3~4

AI summary

A fixing device (20, 20', 20") includes a fixing member (21, 21'), a heating means (25, 38, 50), a pressure rotator (31), and a nip forming member (26, 26'). The fixing member (21, 21') is rotatable and has an endless shape. The heating means (25, 38, 50) heats the fixing member. The pressure rotator (31) is disposed outside the fixing member to press the fixing member. The nip forming member (26, 26') is disposed inside the fixing member (21, 21') to form a nip between the fixing member and the pressure rotator (31). The nip forming member (26, 26') includes a vapor chamber (28) and a holding member (30). Heat is transferred from an inner circumferential face of the fixing member (21, 21') to the vapor chamber (28). The holding member (30) holds the vapor chamber (28) and includes a plurality of protrusions (30a) in contact with the vapor chamber.