Fixing Device Temperature Sensor Assembly with Biasing and Locking

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Solution Overview

Problem

Existing fixing devices in image forming apparatuses face issues with unstable assemblability and reduced assembly efficiency due to the lack of stable positioning and engagement of the temperature sensor and sensor holding member with the heater holding member.

Innovation Solution

The fixing device incorporates a biasing member to stabilize the engagement between the sensor holding member and the heater holding member, using a locking portion and engaged portion to maintain a stable assembly state, enhancing assemblability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the temperature sensor and sensor holding member are assembled with the heater holding member without a biasing member, then the assembly structure is simpler, but the assembly stability and positioning accuracy deteriorate

Engineering Contradiction:
Improveassembly structureVSAvoidassembly stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The biasing member is configured to automatically push the temperature sensor toward the heater, enabling self-positioning and self-adjustment during assembly. This self-service mechanism eliminates the need for complex external positioning systems while ensuring stable assembly composition.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The biasing member is pre-installed in the sensor holding member to perform preliminary positioning action on the temperature sensor before final assembly with the heater holding member. This preliminary action ensures proper alignment and stability are achieved automatically during the assembly process.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the temperature sensor and sensor holding member are assembled without a biasing member, then the assembly process is faster, but the positioning accuracy and assembly efficiency deteriorate

Engineering Contradiction:
Improveassembly efficiencyVSAvoidpositioning accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The biasing member enables the temperature sensor to self-position relative to the heater through automatic mechanical pushing. This self-service capability maintains high positioning accuracy while actually improving assembly efficiency by eliminating manual adjustment requirements.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The biasing member introduces dynamic adjustment capability to the assembly, allowing the temperature sensor to automatically adjust its position during assembly. This dynamic mechanism ensures precise positioning without slowing down the assembly process.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the sensor holding member is freely movable without locking, then the assembly process is easier, but the assembly stability and reliability deteriorate

Engineering Contradiction:
Improveassembly easeVSAvoidassembly reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The locking mechanism is segmented into distinct locking portions on the heater holding member and corresponding locked portions on the sensor holding member. This segmentation allows for easy engagement during assembly while ensuring reliable locked positioning, resolving the contradiction between ease of operation and reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking portions are designed to automatically engage with the locked portions when the sensor holding member is positioned correctly, performing the locking action as a preliminary step. This preliminary locking action ensures reliability without complicating the assembly process.

Inventive Principle:
Principle #10Preliminary action

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 allows for more stable assembly of the fixing device components, improving assembly efficiency and maintaining the positional relationships of the heater and temperature sensor, thereby enhancing the overall assembly process.

Implementation Method 1

The sensor holding member includes a biasing member. The biasing member faces the heater holding member via the temperature sensor and biases the temperature sensor in a direction directed from the temperature sensor to the heater.

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The heating device includes a heater that heats the fixing belt and faces an inner peripheral surface of the fixing belt.

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

The pressurizing member sandwiches the fixing belt between the pressurizing member itself and the heater, forms a fixing nip portion, in which a recording medium is sandwiched and transported, between the pressurizing member and the fixing belt.

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4603921A1Fixing device and image forming apparatus
Publication Date: 2025.08.20 KYOCERA DOCUMENT SOLUTIONS INC
  • EP4603921A1 patent drawingFigure 1
  • EP4603921A1 patent drawingFigure 2
  • EP4603921A1 patent drawingFigure 3A~3C

AI summary

A fixing device (13) includes a fixing belt (20), a heating device (30), and a pressurizing member (40). The heating device (30) includes a heater holding member (32), a temperature sensor (33) that faces a heater (31) and is disposed in the heater holding member (32), and a sensor holding member (34) that is assembled with the heater holding member (32) in a direction of facing the temperature sensor (33) and includes a biasing member (35) that biases the temperature sensor (33). The heater holding member (32) includes a locking portion (323) that locks one end (341) of the sensor holding member (34), and an engaged portion (325) engaged with an engaging portion (342) provided in the sensor holding member (34) at a different position from the one end (341) in a length direction of the sensor holding member (34) when the sensor holding member (34) moves in the length direction with the one end (341) locked by the locking portion (323), the engaging portion (342) receiving the sensor holding member (34) pressed by a counterreaction of biasing.