Image Heating Controller Switching Temperature Detection Modes

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Solution Overview

Problem

The increasing demand for devices capable of handling various sheet sizes in image forming apparatuses leads to challenges in space allocation and cost due to the need for multiple temperature detecting elements, which complicates electrical circuits and increases energy consumption.

Innovation Solution

An image heating apparatus with a cylindrical film, a heater, and multiple temperature detecting elements to control heating based on the sheet width, allowing for efficient temperature management by switching between different control modes depending on the sheet width, thereby reducing the number of necessary temperature detecting elements and simplifying the control system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple temperature detecting elements are provided for detecting temperature rise in non-sheet-passage-part areas, then temperature control precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvetemperature detection precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The single temperature detecting element is positioned to serve multiple detection purposes: it detects temperatures in both the non-sheet-passage-part area and the sheet-passage area, allowing one element to perform the function of multiple elements through strategic placement and multi-mode operation

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the functions of multiple temperature detecting elements into a single element by positioning it to detect temperatures across different areas (non-sheet-passage-part and sheet-passage area) and using it for multiple control purposes, thereby reducing the total number of elements required

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

Engineering Contradiction:

Improvetemperature detection precisionVSAvoidenergy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The single temperature detecting element operates in multiple modes to detect temperatures in different areas and provide control signals for various heating zones, eliminating the need for multiple elements and their associated energy consumption while maintaining comprehensive temperature monitoring capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

Engineering Contradiction:

Improvetemperature detection precisionVSAvoidspace allocation

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

By positioning a single temperature detecting element to serve multiple detection purposes across different areas, the patent eliminates the need for multiple elements that would require separate space allocation, thereby solving the space constraint problem while maintaining comprehensive temperature monitoring

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Temperature

If sheet feeding timing is delayed to prevent non-sheet-passage-part temperature rise, then temperature control is improved, but productivity decreases

Engineering Contradiction:

Improvetemperature controlVSAvoidproductivity

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The temperature detecting element provides real-time feedback on temperatures in both non-sheet-passage-part and sheet-passage areas, enabling the control unit to dynamically adjust heating operations and sheet feeding timing based on actual temperature conditions, thereby maintaining temperature control without unnecessary delays that would reduce productivity

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts its operation based on real-time temperature feedback, allowing flexible control of heating and sheet feeding operations to optimize both temperature management and productivity rather than using fixed delay strategies

Inventive Principle:

Principle #15Dynamics

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 solution effectively manages temperature control across different sheet widths, preventing image defects and reducing energy consumption by optimizing the use of temperature detecting elements and adjusting the heating process accordingly.

Implementation Method 1

a ceramic heater, as a heating element

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the thermal resistance increases between the sleeve and the ceramic heater

Methodology Applied

Scientific EffectThermal resistance: Electrical Resistance

Data Source

PatentUS10429776B2Image heating device including a controller that executes first and second heat controls based on temperatures detected by first and second detecting elements

Publication Date: 2019.10.01 CANON KK

AI summary

A controller of an image heating apparatus executes a first heater control operation, when a sheet having a width such that the sheet passes both a position of a first temperature detector and a position of a second temperature detector, is heated in a nip, for controlling power supply to a heater so that a temperature detected by the second temperature detector is maintained at a heater target temperature, and a second heater control operation, when a sheet having a width such that the sheet passes through the position of the first temperature detector, but does not pass through the position of the second temperature detector, is heated in the nip, for controlling the power supply to the heater, so that the temperature detected by the first temperature detector, irrespective of the temperature detected by the second temperature detector, is maintained at a film target temperature.