Heater Support Segmentation for Thermal Stress and Rise Time

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Solution Overview

Problem

Image heating apparatuses face challenges in achieving a short rise time and high reliability while effectively suppressing temperature rises at non-sheet-passing portions during continuous printing of small-sized recording materials.

Innovation Solution

The image heating apparatus incorporates a high heat-conductive member sandwiched between a ceramic heater and a heater supporting member, with a specific structure that includes a pressure region and a non-pressure region to enhance heat conduction and reduce thermal stress, allowing for efficient temperature control and rapid heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a high heat-conductive member is sandwiched between the heater and heater supporting member to suppress non-sheet-passing portion temperature rise, then temperature control is improved, but the rise time to reach predetermined temperature increases

Engineering Contradiction:
Improvetemperature controlVSAvoidrise time
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

The heater supporting member is divided into a pressure region (first region) and a non-pressure region (second region). The high heat-conductive member is pressed against the heater in the pressure region to suppress temperature rise at non-sheet-passing portions, while the non-pressure region allows faster heat transmission to reduce rise time. This segmentation resolves the contradiction between temperature control and rise time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the heater supporting member have different properties: the pressure region has high contact pressure for heat dissipation to adjacent areas, while the non-pressure region has low contact pressure for rapid heating. This local differentiation allows simultaneous achievement of temperature control and fast response.

Inventive Principle:
Principle #3Local quality

2Temperature

If the high heat-conductive member is pressed against the heater to suppress temperature rise, then temperature distribution is improved, but thermal stress on the heater increases

Engineering Contradiction:
Improvetemperature distributionVSAvoidthermal stress
Core Design Contradiction:
TemperatureVSStress or pressure

Solution Approach 1:

The heater supporting member is segmented into a pressure region and a non-pressure region. By concentrating the pressing force only in the pressure region and releasing it in the non-pressure region, the design achieves temperature distribution control while preventing excessive thermal stress that would occur with uniform pressing across the entire heater surface.

Inventive Principle:
Principle #1Segmentation

3Loss of energy

If uniform pressure is applied across the entire heater surface, then heat conduction is maximized, but response time increases and thermal stress accumulates

Engineering Contradiction:
Improveheat conduction efficiencyVSAvoidresponse time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

Instead of uniform pressure application, the design uses localized pressure only in the pressure region where heat dissipation is needed. The non-pressure region maintains low contact pressure to enable rapid heat transmission and fast response time, resolving the contradiction between heat conduction efficiency and response time.

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 enables a shorter time to reach a predetermined temperature and improves the reliability of the image heating apparatus by efficiently conducting heat and reducing thermal stress, thus effectively suppressing temperature rises at non-sheet-passing portions.

Implementation Method 1

a high heat-conductive member having high thermal conductivity is sandwiched between a heater supporting member and a ceramic heater

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP3998511B1Image heating apparatus
Publication Date: 2023.08.30 CANON KK
  • EP3998511B1 patent drawingFigure 1
  • EP3998511B1 patent drawingFigure 2
  • EP3998511B1 patent drawingFigure 3

AI summary

An image heating apparatus includes: a heater including a substrate and a heat generating element; a supporting member; a high heat-conductive member. The recording material on which an image is formed is heated by heat from the heater. The supporting member has a bottom region, where the supporting member supports the heater, including a first region where the supporting member contacts the high heat-conductive member so as to apply pressure between the heater and the high heat-conductive member and including a second region where the supporting member is recessed from the high heat-conductive member relative to the first region. At least a part of the first region overlaps, with respect to a movement direction of the recording material, with a region where the heat generating element is provided.