Elastic Seal for Contactless Temperature Sensor in Image Forming Apparatus

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Solution Overview

Problem

Conventional image forming apparatuses using contactless temperature sensors face issues with temperature detection precision due to air flow influencing the fixing unit, leading to temperature variations and image quality issues, and existing solutions like infrared windows are prone to detection errors from surface state variations and moisture-induced cloudiness.

Innovation Solution

An image forming apparatus with a contactless temperature sensor attached to the main body, detecting the temperature of the heating member through an opening in the fixing unit's outer casing, and an elastic seal surrounding the space between the opening and the sensor to prevent air flow, ensuring accurate temperature control and improved image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a contactless type temperature sensor is used to detect the temperature of the fixing unit, then the precision of temperature detection is improved and image quality is enhanced, but air flow around the fixing unit influences the detection accuracy causing temperature variations and detection errors

Engineering Contradiction:

Improvetemperature detection precisionVSAvoidair flow influence

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an elastic seal as an intermediary element between the temperature sensor and the fixing unit. This seal fills the gap and prevents air flow from directly influencing the detection area, while still allowing the sensor to detect temperature through it. The elastic material transmits thermal energy while blocking harmful air convection currents.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs an elastic seal (flexible shell) to surround the temperature detection area. This flexible barrier prevents air flow intrusion while maintaining thermal conductivity for accurate temperature detection. The elastic nature allows it to adapt to the gap between the sensor and fixing unit surface.

Inventive Principle:

Principle #30Flexible shells and thin films

2Object-affected harmful factors

If an infrared transmitting window is used to prevent air flow, then air inflow is blocked, but detection errors occur due to surface state variations and moisture-induced cloudiness

Engineering Contradiction:

Improveair flow preventionVSAvoidtemperature detection accuracy

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent replaces the expensive and problematic infrared transmitting window with a simple elastic seal that is part of the disposable fixing unit assembly. This eliminates issues with surface state variations and moisture cloudiness while maintaining effective air flow prevention.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces the optical-based infrared window system with a mechanical elastic seal system. This substitution eliminates optical interference problems while achieving the same goal of preventing air flow influence on temperature detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If the contactless sensor is arranged at a predetermined distance from the fixing unit surface, then the sensor can detect temperature without contact, but a certain space must be assured into the fixing unit increasing device complexity

Engineering Contradiction:

Improvecontactless temperature detectionVSAvoidfixing unit structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The elastic seal serves as a flexible barrier that can be integrated into the existing fixing unit structure without requiring additional space. It fills the minimal gap between the sensor and fixing unit surface, maintaining contactless detection while preventing air flow intrusion.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent integrates the elastic seal as part of the fixing unit assembly, separating the sealing function from the sensor mounting. This modular approach allows the seal to be included in the disposable fixing unit while the sensor remains on the permanent apparatus body.

Inventive Principle:

Principle #1Segmentation

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 elastic seal effectively prevents air inflow, stabilizing temperature detection and improving image quality by maintaining precise temperature control and reducing the risk of detection errors, enhancing the reliability and stability of the temperature detection and control process.

Implementation Method 1

an elastic seal surrounding a space between the opening and the sensor to prevent air flow

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a contactless type sensor such as a thermopile

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentUS7522861B2Image forming apparatus having contactless type temperature sensor

Publication Date: 2009.04.21 CANON KK

AI summary

A sealing member which is compressed by a contactless temperature sensor and a cover member of a fixing unit is provided between the sensor and the cover member. An opening portion for temperature detection is shut off from a space around the fixing unit by the sealing member, thereby preventing the air from flowing from the opening portion into the fixing unit.