Temperature Estimation in Image Forming Apparatus Using Thermal Coupling
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately estimating the temperature of target portions, especially after power restoration, due to limitations in sensor placement and cost considerations, leading to potential defective images from excessive internal temperature increases.
Innovation Solution
The image forming apparatus includes a detection unit for temperature measurement and an estimation unit that uses historical operation data and temperature changes to accurately estimate the temperature of target portions, such as process cartridges and the fixing unit, by employing temperature estimation parameters and coefficients to model temperature rise and fall characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are arranged at all portions likely to be affected by heat, then temperature measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a temperature sensor placed in the fixing unit as an intermediary to indirectly estimate the temperature of other components (process cartridges, development motors) through thermal coupling relationships. Instead of directly measuring temperatures at multiple locations, the system measures temperature at one location and uses thermal models to estimate temperatures at other locations, thereby reducing the number of sensors needed while maintaining estimation accuracy.
2Measurement precision
If temperature sensors are arranged at all portions likely to be affected by heat, then temperature measurement accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The system employs a single temperature sensor in the fixing unit as a cost-effective intermediary measurement point. By establishing thermal coupling relationships between the fixing unit and other components, the system can estimate temperatures throughout the image forming apparatus using data from one sensor, significantly reducing the number of expensive temperature sensors required while maintaining adequate temperature monitoring capability.
3Reliability
If the estimated temperature is used to control operation, then prevention of defective images is improved, but estimation accuracy deteriorates after power restoration
Solution Approach 1:
The patent stores temperature information and operation history data in memory before power restoration occurs. When power is restored, the system retrieves this previously stored data and uses it as initial conditions for temperature estimation calculations. This preliminary preparation of data ensures that temperature estimation can immediately resume with high accuracy after power restoration, avoiding the accuracy deterioration that would otherwise occur during the warm-up period.
Solution Approach 2:
The system continuously monitors actual temperature sensor readings and compares them with estimated temperatures to refine estimation parameters. After power restoration, the system uses feedback from the temperature sensor and operation history to iteratively improve temperature estimates, ensuring that reliability is maintained even during the transition period when estimation accuracy might initially be lower.
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 approach significantly improves the accuracy of temperature estimation at power-on conditions, preventing excessive temperature increases and ensuring high-quality image formation by effectively controlling the operation of the image forming apparatus.
Implementation Method 1
a detection unit configured to detect a temperature of a first member
Implementation Method 2
the temperature of the second member estimated by the estimation unit at a first timing, which is a timing before the image forming apparatus is powered off, the temperature of the first member detected by the detection unit at a second timing, which is a timing after the image forming apparatus is powered on
Data Source
AI summary
An image forming apparatus configured to form an image on a recording material includes a detection unit configured to detect a temperature of a first member, and an estimation unit configured to estimate a temperature of a second member, which is different from the first member. The estimation unit is configured to estimate, based on the temperature of the second member estimated by the estimation unit at a first timing, which is a timing before the image forming apparatus is powered off, the temperature of the first member detected by the detection unit at a second timing, which is a timing after the image forming apparatus is powered on, and information representing an operation history of the image forming apparatus until when the image forming apparatus is powered off, the temperature of the second member at the second timing.