Image Heating Member Curie Point Control for Standby Energy Efficiency
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Solution Overview
Problem
Conventional image heating apparatuses face issues with high energy consumption and slow warm-up times, and the temperature control of image heating members made of magnetic alloys can lead to excessive heat generation and power source overheating due to improper positioning of temperature detecting members and uneven heating.
Innovation Solution
An image heating apparatus with a Curie point-adjusted image heating member and a temperature detecting system that controls electric power supply to maintain the temperature below the Curie point across the image heating member, preventing excessive current flow and reducing power source stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the temperature detecting member is positioned to detect the temperature of a portion of the image heating member that is small in the amount of heat generated, then the device complexity is reduced, but the temperature control precision deteriorates leading to excessive heat generation in other portions
Solution Approach 1:
The patent applies local quality by positioning the temperature detecting member to detect temperature at a specific location (one end in the axial direction) of the image heating member, while the control system compensates for temperature variations across different regions. This allows simplified detection at one point while maintaining overall temperature control precision through understanding of the heat generation distribution pattern.
Solution Approach 2:
The patent implements feedback control where the temperature detecting member continuously monitors the temperature of the image heating member, and the high-frequency power source adjusts its output based on this feedback to maintain temperatures below the Curie point. This feedback mechanism ensures that even with detection at a single point, the entire heating member remains within safe temperature limits.
2Use of energy by moving object
If the image heating member is controlled in temperature while kept stationary in standby mode, then the energy consumption is reduced, but the temperature uniformity deteriorates causing portions to exceed Curie point
Solution Approach 1:
The patent applies preliminary action by pre-positioning the temperature detecting member at a strategic location that provides information about the highest temperature region. The control system uses this advance information to adjust power supply before temperature excursions occur, preventing any portion from exceeding the Curie point while maintaining energy efficiency in standby mode.
Solution Approach 2:
The patent changes the operating parameters of the image heating member by adjusting the temperature setpoint and power supply levels based on the detected temperature and operational mode (standby vs. active). This dynamic parameter adjustment allows the system to maintain temperature uniformity below the Curie point while minimizing energy consumption during standby periods.
3Loss of energy
If high frequency current is flowed through the coil to heat the image heating member, then the heat generation efficiency is improved, but the power source load increases causing overheating
Solution Approach 1:
The patent implements feedback control where the temperature of the image heating member is continuously monitored and used to adjust the high-frequency power supply in real-time. This prevents excessive power loading by reducing power when temperatures approach the Curie point, while maintaining high heat generation efficiency during normal operation by optimizing power delivery based on actual temperature conditions.
Solution Approach 2:
The patent applies dynamics by making the power supply to the coil dynamically adjustable based on temperature feedback. The system transitions between different power levels depending on operational requirements and temperature conditions, allowing high efficiency heating when needed while preventing power source overheating through automatic power reduction when temperature limits are approached.
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 reduces the load on high-frequency power sources, prevents overheating, and ensures uniform temperature distribution, thereby improving energy efficiency and extending the lifespan of the power source.
Implementation Method 1
high frequency current is flowed through the coil (exciter coil). As the current is flowed, current (eddy current) is induced in the image heating member by the magnetic field generated by the coil
Implementation Method 2
heat (Joule heat) is generated in the image heating member by the interaction between the skin resistance of the image heating member and the eddy current
Implementation Method 3
an image heating apparatus which employs a heating method based on magnetic induction, which is very high in heat generation efficiency
Data Source
AI summary
An image heating apparatus has a coil; a rotatable image heating member capable of generating heat by a magnetic flux generated by the coil to heat an image; a temperature detecting member; an electric power supply controller for controlling electric power supply to the coil; and an execution portion for executing a stand-by mode operation in which the image heating member is at rest, and the apparatus waits for input of an image formation signal while the electric power supply controller carries out its power supply control operation such that in the stand-by mode, along no longitudinal line on said image heating member, the temperature of the image heating member exceeds Curie temperature on an entirety of the longitudinal line.