Image Heating Device Asymmetric Temperature Control
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Solution Overview
Problem
Image heating devices face issues with lateral temperature differences causing thermal expansion disparities in pressure rollers, leading to uneven film feed and potential damage from transverse forces, while uniform heating results in power wastage.
Innovation Solution
An image heating device with a heater having multiple heating elements and a control system that adjusts power distribution based on image presence, maintaining average temperatures within specific ranges to balance heat distribution and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If uniform heating is applied across the entire heater, then the temperature distribution is even, but power is wasted in non-image portions
Solution Approach 1:
The heater is divided into multiple heat generation blocks along the conveying direction, with each block independently controllable. This allows selective heating of only those blocks that correspond to image portions, while reducing or stopping heating in blocks corresponding to non-image portions, thereby eliminating power waste while maintaining temperature uniformity where needed.
Solution Approach 2:
Different regions of the heater are assigned different heating characteristics based on their function. Image portion blocks receive full heating power to ensure proper fixing temperature, while non-image portion blocks receive reduced or zero power. This local differentiation optimizes both energy efficiency and fixing quality.
2Loss of energy
If selective heating is applied only to image portions, then power is saved, but lateral temperature differences cause thermal expansion disparities in pressure rollers
Solution Approach 1:
The invention introduces asymmetric control strategies where the degree of power reduction in non-image blocks is carefully calibrated to compensate for lateral temperature differences. By adjusting the power distribution asymmetrically across different blocks, the system maintains overall temperature balance while still achieving power savings in non-image portions.
Solution Approach 2:
The control system dynamically adjusts the power supply parameters to each heat generation block based on real-time temperature feedback and predetermined temperature difference thresholds. When lateral temperature differences exceed thresholds, the system modifies power distribution parameters to restore thermal balance, preventing pressure roller expansion disparities.
3Stability of the object's composition
If lateral temperature differences are suppressed, then pressure roller thermal expansion is uniform, but the device complexity increases
Solution Approach 1:
The control system operates dynamically by continuously monitoring temperature differences between adjacent blocks and adjusting power distribution in real-time. The system activates only when temperature differences exceed predetermined thresholds, remaining passive otherwise. This dynamic operation simplifies the control logic while maintaining temperature uniformity.
Solution Approach 2:
Temperature detection means provide feedback signals to the control means, enabling automatic adjustment of power distribution based on actual temperature conditions. This closed-loop feedback mechanism simplifies complex temperature balancing by using simple threshold-based control logic rather than complex predictive algorithms.
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 achieves both power-saving and extended device lifespan by minimizing lateral temperature differences and preventing film damage from uneven thermal expansion.
Implementation Method 1
a heater (300) having a plurality of heating elements (302a, 302b) arranged in a direction orthogonal to a conveying direction of a recording material
Implementation Method 2
a pressure roller (208) that forms a fixing nip portion N together with the heater (300) with the fixing film (202) interposed therebetween
Implementation Method 3
the fixing film and a pressure roller (208) form a pressure contact nip portion. Then, a non-fixed toner image on the recording material is heated and fixed
Data Source
Figure 1
Figure 2(A)~2(B)
Figure 3(A)~3(C)
AI summary
In this image heating device, a control portion controls the supply of electric power to a plurality of heating elements such that a first average temperature which is an average value of control target temperatures of heating regions included in a first region located closer to one end side than a central heating region in a direction orthogonal to a conveying direction of a recording material among a plurality of heating regions heated by a plurality of heating elements of a heater and a second average temperature which is an average value of control target temperatures of heating regions included in a second region located closer to the other end side than the central heating region are within a predetermined temperature range.