Fixing Member Temperature Estimation Algorithm

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Solution Overview

Problem

Existing image forming apparatuses face challenges in accurately diagnosing the internal temperature of fixing device members, leading to inaccurate deterioration diagnosis due to reduced thermal conductivity materials, which cause temperature differences between the surface and internal temperatures, and the complexity and cost of sensor arrangements.

Innovation Solution

An image forming apparatus with a hardware processor that estimates the temperature of the fixing member based on the heating member's temperature and calculates the durability state, using algorithms to estimate the nip portion's temperature without the need for additional sensors, by measuring rotation time and control time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If thermal conductivity is reduced for energy saving, then energy consumption is decreased, but temperature uniformity deteriorates and temperature difference between surface and internal temperatures increases

Engineering Contradiction:

Improveenergy consumptionVSAvoidtemperature uniformity

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent introduces thermal conductivity coefficients as an intermediary parameter to model heat transfer behavior. By using different thermal conductivity coefficients for the elastic layer (first coefficient) and the core (second coefficient), the system can accurately calculate internal temperatures based on surface temperature measurements, resolving the temperature uniformity issue while maintaining low thermal conductivity materials for energy savings.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If surface temperature is detected, then measurement simplicity is improved, but internal temperature detection accuracy deteriorates

Engineering Contradiction:

Improvemeasurement simplicityVSAvoidinternal temperature detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent creates a thermal model that copies the heat transfer behavior of the fixing device. By measuring surface temperature and using thermal conductivity coefficients to calculate internal temperature distribution, the system obtains accurate internal temperature data without physically placing sensors inside the fixing device, thus maintaining measurement simplicity while improving internal temperature detection accuracy.

Inventive Principle:

Principle #26Copying

3Measurement precision

If sensors are provided for internal temperature detection, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improveinternal temperature detection accuracyVSAvoidsensor arrangement complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses thermal conductivity coefficients as mathematical intermediaries to bridge the gap between surface temperature measurements and internal temperature conditions. This approach eliminates the need for complex sensor arrangements inside the fixing device while maintaining high measurement precision for internal temperatures.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Use of energy by moving object

If thermal conductivity is reduced, then energy efficiency is improved, but deterioration diagnosis accuracy deteriorates

Engineering Contradiction:

Improveenergy efficiencyVSAvoiddeterioration diagnosis accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent creates an accurate thermal model that copies the heat transfer characteristics of the fixing device using thermal conductivity coefficients. This model enables precise calculation of internal temperatures and temperature differences, which are critical for deterioration diagnosis. The system can accurately diagnose member deterioration by analyzing temperature differences between the surface and internal temperatures, even when using low thermal conductivity materials for energy efficiency.

Inventive Principle:

Principle #26Copying

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

Enables precise deterioration diagnosis and temperature estimation, improving the accuracy of fixing device maintenance without the requirement for additional sensors, thus reducing costs and complexity.

Implementation Method 1

a heating member having a heat source; a pressing member; and a fixing member heated by the heating member

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10289040B2Image forming apparatus, method of controlling image forming apparatus, and program

Publication Date: 2019.05.14 KONICA MINOLTA INC

AI summary

An image forming apparatus includes: a fixing device having: a heating member having a heat source; a pressing member; and a fixing member heated by the heating member and forming a nip portion passing through a recording material together with the pressing member; and a hardware processor that: estimates a temperature of the fixing member based on a temperature of the heating member; and estimates a durability state of the fixing member according to the temperature of the fixing member estimated.