Parallel Resistance Heating Elements for Uniform Temperature Control
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Solution Overview
Problem
Existing fixing devices in electrophotographic image forming apparatuses face challenges in maintaining uniform temperature across resistance heating elements, leading to potential anomalies and inefficiencies in heating processes.
Innovation Solution
A heating device with a base, multiple resistance heating elements connected in parallel, and a control system using first and second temperature sensors to regulate power supply, ensuring all elements reach a predetermined temperature and cutting off power when a second predetermined temperature is sensed to prevent anomalies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple resistance heating elements are used to heat the fixing belt, then the heating efficiency is improved, but the temperature uniformity across the heating elements deteriorates
Solution Approach 1:
The heating system is divided into multiple independent resistance heating elements (first, second, third, and fourth heating elements) that can be controlled separately. Each heating element has its own temperature sensor and control circuit, allowing individual temperature regulation to achieve uniform heating across the entire fixing belt while maintaining high heating efficiency
Solution Approach 2:
Different regions of the fixing belt are heated by dedicated heating elements with localized temperature control. The control circuitry adjusts power supply to each heating element based on its specific temperature sensor readings, ensuring that each local region reaches the required temperature uniformly without affecting other regions
2Temperature
If temperature control is implemented to maintain uniform heating, then the temperature uniformity is improved, but the device complexity increases
Solution Approach 1:
Each heating element is equipped with its own temperature sensor that continuously monitors its temperature and feeds back to the control circuitry. The system automatically adjusts power supply to each heating element based on its own temperature status, achieving self-regulating temperature control without requiring complex external monitoring systems
Solution Approach 2:
The control circuitry is designed to maintain equal temperature (thermal equipotential) across all heating elements by comparing temperature sensor readings and adjusting power distribution accordingly. This ensures uniform heating while using a relatively simple control architecture that equalizes temperature conditions across the system
3Temperature
If power is continuously supplied to maintain temperature, then the temperature stability is improved, but the energy consumption increases
Solution Approach 1:
The control circuitry supplies power to heating elements in a periodic on-off manner based on temperature sensor feedback. When a heating element reaches the target temperature, power supply is interrupted; when temperature drops below the target, power is restored. This periodic control maintains temperature stability while minimizing energy consumption compared to continuous power supply
Solution Approach 2:
Temperature sensors continuously monitor the temperature of each heating element and provide feedback to the control circuitry. The control circuitry adjusts power supply based on this feedback, increasing power when temperature is low and decreasing or cutting off power when temperature is sufficient, thereby maintaining temperature stability with optimized energy consumption
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 ensures uniform temperature distribution across the heating elements, preventing anomalous temperature increases and maintaining efficient heating processes, thereby enhancing the reliability and performance of the fixing device and image forming apparatus.
Implementation Method 1
a plurality of resistance heating elements disposed in a longitudinal direction of the base and electrically connected in parallel with each other
Implementation Method 2
a first temperature sensor configured to sense a temperature of a first resistance heating element of the plurality of resistance heating elements and a second temperature sensor configured to sense a temperature of a second resistance heating element
Implementation Method 3
The heating device is configured to heat the belt member and transfer heat of the belt member to the fixing nip
Data Source
AI summary
A heating device includes a base, a plurality of resistance heating elements, a power control circuit, a first temperature sensor, a second temperature sensor, and control circuitry. The resistance heating elements is disposed in a longitudinal direction of the base and electrically connected in parallel with each other. The power control circuit is configured to supply electrical power to the resistance heating elements. The control circuitry is configured to control an electrical power amount of the power control circuit so that temperatures of the resistance heating elements become equal to a first predetermined temperature based on a result of sensing with a first temperature sensor of the resistance heating elements and cut off the electrical power supplied from the power control circuit to the resistance heating elements in response to sensing of a second predetermined temperature with a second temperature sensor of the resistance heating elements.