Fixing Roller Lifetime Prediction in Induction-Heated Image Forming
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Solution Overview
Problem
Existing image forming apparatuses using induction heating methods for fixing rollers face challenges in accurately predicting the deterioration of the elastic layer due to heat accumulation in the metal base, leading to loss of elasticity and eventual failure.
Innovation Solution
An image forming apparatus with a control system that calculates the cumulative electric power supply time and uses a lifetime prediction formula to determine the remaining lifetime of the fixing roller's elastic layer, based on the supplied electric power, by excluding non-contributory power usage and accurately estimating the temperature of the metal base.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If induction heating is used to heat the fixing belt, then heating efficiency is improved, but leakage flux causes heat accumulation in the metal base of the fixing roller
Solution Approach 1:
The patent converts the harmful leakage flux that causes heat accumulation in the metal base into useful information by measuring the temperature rise of the metal base and using it to predict the remaining lifetime of the elastic layer. The control unit calculates cumulative heating time based on temperature measurements, transforming a harmful thermal effect into a diagnostic tool for maintenance scheduling.
2Temperature
If the elastic layer is exposed to high temperature for extended periods, then the fixing function is maintained, but the elastic layer deteriorates and loses elasticity
Solution Approach 1:
The patent implements a feedback mechanism where the temperature of the metal base is continuously monitored, and this information is fed back to the control unit. The control unit calculates the cumulative heating time and uses it to determine the remaining lifetime of the elastic layer, providing feedback for maintenance scheduling that prevents operation beyond the elastic layer's safe temperature exposure limits.
Solution Approach 2:
The patent performs preliminary assessment of the elastic layer's remaining lifetime by calculating cumulative heating time before actual failure occurs. This allows proactive maintenance scheduling, replacing the elastic layer before it completely deteriorates, thus preventing image quality degradation and ensuring continuous operation within safe temperature exposure parameters.
3Productivity
If the fixing roller operates continuously, then productivity is improved, but the elastic layer deteriorates faster due to cumulative heating
Solution Approach 1:
The control unit continuously monitors the cumulative heating time of the metal base and provides feedback on the remaining lifetime of the elastic layer. This allows the system to operate continuously at high productivity while tracking the degradation state, enabling maintenance to be scheduled before reliability deteriorates to unacceptable levels.
Solution Approach 2:
The fixing roller system performs self-diagnosis by using the temperature rise of its own metal base (caused by leakage flux during normal operation) as an indicator of elastic layer deterioration. This self-service capability eliminates the need for external monitoring equipment while providing reliable data on component health and remaining service life.
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 prediction of the fixing roller's remaining lifetime, allowing for proactive maintenance and minimizing downtime by indicating the remaining lifetime on a gauge, thus ensuring efficient operation.
Implementation Method 1
a fixing device which includes a fixing member having a fixing roller or a fixing belt (i.e., heated rotary member)... The fixing device of a belt fixing type using the fixing belt employs the induction heating method in which a heating layer of the fixing belt is heated by electromagnetic induction
Implementation Method 2
employs the induction heating method in which a heating layer of the fixing belt is heated by electromagnetic induction
Implementation Method 3
as the leakage flux reaches the metal base of the fixing roller, the metal base is slightly heated due to surface resistance
Implementation Method 4
the metal base is slightly heated due to surface resistance
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An image forming apparatus (100) includes an image forming portion (Pa to Pd), a fixing device (13), a fixing voltage power supply (55), and a control portion (90). The fixing device (13) includes an endless fixing belt (20), a fixing roller (21) inside it with a metal base (21a) and an elastic layer (21b) on its outer circumference, a pressing roller (22) in pressed contact with the fixing roller (21) across the fixing belt (20), and an induction heating portion (23) heating the fixing belt (20). The control portion (90) calculates, as a cumulative electric power supply time, the cumulative value of the supply time of a predetermined electric power supplied to the induction heating portion (23), and determines the remaining lifetime of the fixing roller (21) by comparing, as its lifetime, the failure time y [min] of the elastic layer (21b), calculated with the supplied electric power substituted in the damage electric power x [W] in lifetime prediction formula (1), with the cumulative electric power supply time.