Fixing Belt Power Control With Dual Temperature Feedback
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Solution Overview
Problem
The existing fixing devices in electrophotographic image forming apparatuses face issues with temperature instability in the nip region due to excessive heating of the resistance heating element, leading to potential breakdowns and poor image quality, as the power control is based on the temperature of the fixing belt rather than the heater, resulting in unstable temperature regulation.
Innovation Solution
A power control method is implemented with a first power supply control in a first control cycle until the target temperature is reached, followed by a correction control in a second control cycle to adjust the target temperature based on belt and heater temperature detection, ensuring the fixing belt and heater temperatures remain within a stable range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If power is supplied to the resistance heating element based on the temperature of the fixing belt, then the fixing belt temperature can be controlled, but the resistance heating element becomes excessively heated and breaks down
Solution Approach 1:
The patent implements a feedback control system that uses both belt temperature detection and heater temperature detection to control power supply. The control unit adjusts power supply to the heater based on feedback from both temperature sensors, ensuring the heater temperature does not exceed a predetermined threshold while maintaining proper fixing belt temperature. This dual-feedback mechanism prevents excessive heater heating and breakdowns.
2Temperature
If power supply to the resistance heating element is stopped when the fixing belt temperature exceeds the target temperature, then the fixing belt temperature control is achieved, but the temperature becomes unstable and proper fixing cannot be performed
Solution Approach 1:
The patent changes the control parameters by introducing heater temperature as an additional controlled variable alongside belt temperature. The control unit monitors both temperatures and adjusts power supply accordingly, preventing the heater from excessive heating while maintaining stable fixing belt temperature within the target range. This dual-parameter control ensures both temperature control and stability.
3Stability of the object's composition
If the second control cycle is set at a time interval 10 times or more the first control cycle, then the heater temperature can be stabilized, but the response time for temperature correction is delayed
Solution Approach 1:
The patent implements periodic control actions with two different cycles: a first control cycle for rapid belt temperature monitoring and adjustment, and a second control cycle (10 times or more longer) for heater temperature stabilization. This multi-periodic approach allows fast response for belt temperature control while ensuring heater temperature stability through less frequent but more comprehensive adjustments.
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 method stabilizes the temperature of the fixing belt and heater, preventing excessive heating and maintaining proper fixing operations, thereby improving image quality and reducing power wastage.
Implementation Method 1
The heater comes into contact with an inner surface of the fixing belt facing the pressure region, receives electric power, generates heat, and heats the fixing belt
Implementation Method 2
The heater comes into contact with an inner surface of the fixing belt facing the pressure region, receives electric power, generates heat, and heats the fixing belt
Implementation Method 3
The belt temperature detection part detects a temperature of the fixing belt
Implementation Method 4
The heater temperature detection part detects a temperature of the heater
Data Source
AI summary
A fixing device includes a fixing belt, a pressure member, a heater, a belt temperature detection part, a heater temperature detection part, and a power control part. The power control part executes a first power supply control for supply power to the heater, in a first control cycle until the heater temperature detection part detects a target temperature and the belt temperature detection part detects a temperature outside a target range. When the belt temperature detection part detects a temperature outside the target range, the power control part executes a correction control for correcting the target temperature so that the belt temperature detection part detects a temperature within the target range, and a second power supply control for supplying power to the heater so that the heater temperature detection part detects a corrected target temperature, in a second control cycle 10 times or more the first control cycle.