Fixing Rotator Support Geometry for Reliable Temperature Detection

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Solution Overview

Problem

Reducing the size of the conductive support in a fixing device to minimize the fixing rotator size complicates appropriate temperature detection by the temperature detector, potentially leading to short circuits and improper device operation.

Innovation Solution

Incorporating a support with recessed portions or openings facing the exposed conductive portions of the temperature detector to maintain adequate distance and prevent short circuits while allowing for size reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the size of the conductive support is reduced to minimize the fixing rotator size, then the fixing rotator size is reduced, but appropriate temperature detection by the temperature detector becomes difficult

Engineering Contradiction:
Improvefixing rotator sizeVSAvoidtemperature detection reliability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The conductive support is divided into multiple segments with recessed portions or openings, creating isolated conductive regions that prevent short circuits while maintaining structural support function. This segmentation allows the temperature detector's exposed conductive portion to be positioned near the support without causing electrical contact, enabling compact design while preserving detection reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conductive support has non-uniform structure with recessed portions or openings at specific locations where the temperature detector is positioned. This local modification creates adequate clearance zones precisely where needed, allowing the exposed conductive portion of the temperature detector to maintain sufficient distance from the conductive support without compromising overall support functionality.

Inventive Principle:
Principle #3Local quality

2Volume of moving object

If the size of the conductive support is reduced, then the fixing rotator size is reduced, but short circuit between the exposed conductive portion and the support may occur

Engineering Contradiction:
Improvefixing rotator sizeVSAvoidshort circuit risk
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The conductive support is segmented into multiple isolated conductive regions by recessed portions or openings. This segmentation physically separates conductive areas, preventing the exposed conductive portion of the temperature detector from making unintended contact with the conductive support, thereby eliminating short circuit risk in compact configurations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The recessed portions or openings in the conductive support act as intermediary spaces that maintain electrical isolation between the exposed conductive portion of the temperature detector and the conductive support. These intermediary zones provide the necessary clearance without requiring additional insulating components, enabling compact design while preventing harmful electrical contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Ensures accurate temperature detection and proper functioning of the fixing device even with reduced conductive support size, meeting size reduction demands without compromising operational integrity.

Implementation Method 1

a temperature detector that detects a temperature of the fixing rotator

Methodology Applied
Scientific EffectTemperature detection: Thermistor

Implementation Method 2

The support has at least one of a recessed portion or an opening at a position facing the exposed conductive portion of the temperature detector, such that a closest distance between the exposed conductive portion and the support is sufficient to prevent a short circuit

Methodology Applied
Scientific EffectElectrical insulation through geometric design: Geometry

Implementation Method 3

The fixing rotator has a hollow and heats an image to fix the image onto a recording medium

Methodology Applied
Scientific EffectThermal heating: Heating

Data Source

PatentEP4057075B1Fixing device and image forming apparatus incorporating same
Publication Date: 2026.01.28 RICOH CO LTD
  • EP4057075B1 patent drawingFigure 1
  • EP4057075B1 patent drawingFigure 2
  • EP4057075B1 patent drawingFigure 3

AI summary

A fixing device (30) includes a fixing rotator (31), an opposing rotator (32), a temperature detector (40, 34), and a support (33). The fixing rotator (31) has a hollow and heats an image to fix the image onto a recording medium. The opposing rotator (32) forms a fixing nip between the fixing rotator (31) and the opposing rotator (32). The temperature detector (40, 34) includes an exposed conductive portion (40b). The support (33) has conductivity and is disposed in the hollow of the fixing rotator (31) to support the fixing rotator (31) at the fixing nip. The support (33) has at least one of a recessed portion (33e) or an opening (33d) at a position facing the exposed conductive portion (40b) of the temperature detector (40, 34).