Induction-Heated Fixing Member with Segmented End-Heat Control

Solution Overview

Problem

Existing fixing members in induction heating type fixing units experience excessive temperature rise in non-sheet passing portions, leading to potential deterioration and reduced durability due to uneven heat distribution, which also results in inefficient energy consumption.

Innovation Solution

The conductive layer of the fixing member is divided into segments arranged in a longitudinal direction, with each segment electrically separated and formed continuously over the circumference, ensuring less heat generation in end portions compared to central portions when an alternating magnetic field is applied.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the conductive layer is continuous over the entire circumference and longitudinal direction, then the heat generation is uniform, but the temperature rise in non-sheet passing portions becomes excessive

Engineering Contradiction:

Improvetemperature uniformityVSAvoiddurability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The conductive layer is divided into multiple segments in the longitudinal direction, with each segment forming a complete circle around the tubular shape. These segments are electrically separated from each other, creating distinct heating zones. This segmentation allows the central segments to generate heat for image fixation while the end segments generate less heat, preventing excessive temperature rise in non-sheet passing portions and improving overall reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the fixing member are given different heat generation characteristics. The central portion (sheet passing portion) is designed to generate sufficient heat for image fixation, while the end portions (non-sheet passing portions) are configured to generate less heat. This local differentiation ensures that heat is concentrated where needed for fixation while minimizing unnecessary heat in areas that would otherwise deteriorate from excessive temperature.

Inventive Principle:

Principle #3Local quality

2Productivity

If the conductive layer generates heat uniformly throughout, then image fixation is effective, but energy is wasted in non-sheet passing portions

Engineering Contradiction:

Improveimage fixation efficiencyVSAvoidenergy efficiency

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The conductive layer is divided into multiple segments in the longitudinal direction, with each segment forming a complete circle around the tubular shape. These segments are electrically separated from each other, creating distinct heating zones. This segmentation allows the central segments to generate heat for image fixation while the end segments generate less heat, preventing excessive temperature rise in non-sheet passing portions and improving overall reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the fixing member are given different heat generation characteristics. The central portion (sheet passing portion) is designed to generate sufficient heat for image fixation, while the end portions (non-sheet passing portions) are configured to generate less heat. This local differentiation ensures that heat is concentrated where needed for fixation while minimizing unnecessary heat in areas that would otherwise deteriorate from excessive temperature.

Inventive Principle:

Principle #3Local quality

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 configuration reduces temperature rise in non-sheet passing portions, enhances durability, and improves energy efficiency by minimizing unnecessary heat generation in areas not contributing to image fixation.

Implementation Method 1

generates heat by Joule heat which is generated when an induction current circulates around the conductive layer in response to an alternating magnetic field formed by a magnetic field generation member such as a coil

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

fixing units which heat fixing members by the principle of induction heating

Methodology Applied

Scientific EffectInduction heating: Induction Heating

Implementation Method 3

when an induction current circulates around the conductive layer in response to an alternating magnetic field formed by a magnetic field generation member such as a coil

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS12372906B2Fixing member and fixing unit

Publication Date: 2025.07.29 CANON KK

AI summary

A fixing member includes a conductive layer that generates heat when a circulation current in a circumferential direction of the fixing member having a tubular shape is induced. The conductive layer includes segments arranged in a row in a longitudinal direction of the tubular shape and electrically separated from each other. Each segment is formed continuously over an entire circumference of the tubular shape in the circumferential direction. The conductive layer is configured such that a heat generation amount in an end portion of the fixing member in the longitudinal direction is less than a heat generation amount in a central portion of the fixing member in the longitudinal direction when an alternating magnetic field is applied to a whole area of the fixing member in the longitudinal direction in a state where a temperature of the central portion is equal to a temperature of the end portion.