Image Heating Apparatus Uniform Temperature Control
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Solution Overview
Problem
Image heating apparatuses in electro-photographic or electrostatic recording devices face challenges in achieving power saving while minimizing image defects such as gloss value unevenness and hot offset, which occur due to varying start-up times of heat generating blocks.
Innovation Solution
The image heating apparatus is designed with independently controllable heat generating blocks, where the start-up sequence is controlled using a combination of fixed duty cycle and proportional-integral (PI) control to ensure that all blocks reach a uniform temperature before the recording material is conveyed, thereby reducing heating unevenness and image defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If heat generating blocks are independently controlled for power saving, then power consumption is reduced, but temperature uniformity deteriorates causing image defects
Solution Approach 1:
The control device performs preliminary action by determining the start-up requirement time for each heat generating block before operation begins. Based on these predetermined times, the control device sets appropriate target temperatures for each block in advance, ensuring that all blocks reach uniform temperature simultaneously when the recording material is conveyed, thus preventing image defects while maintaining power saving benefits
Solution Approach 2:
The control device changes the target temperature parameter for each heat generating block based on its specific start-up requirement time. By adjusting the target temperature according to the block's heating characteristics, the system ensures uniform temperature distribution across all blocks at the time of material conveyance, resolving the temperature uniformity issue while preserving independent control for power saving
2Use of energy by moving object
If heat generating blocks operate with different start-up times, then power saving is achieved, but image quality deteriorates due to gloss value unevenness and hot offset
Solution Approach 1:
The control device uses feedback by continuously monitoring the temperature of each heat generating block and comparing it with the predetermined target temperature. Based on this feedback, the control device adjusts the power supply to each block in real-time, ensuring that all blocks reach their target temperatures simultaneously, thereby preventing image defects while maintaining power saving operation
Solution Approach 2:
The system performs preliminary determination of start-up requirement times and target temperatures for each heat generating block before the heating process begins. This preliminary configuration enables the control device to coordinate the heating of all blocks so that they reach uniform temperature simultaneously, preventing image quality defects while preserving power saving benefits
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 maintains power saving performance while significantly reducing image defects like gloss value unevenness and hot offset by ensuring all heat generating blocks reach a uniform temperature before the recording material is processed.
Implementation Method 1
a heater (a heating region) is divided into a plurality of heat generating blocks with respect to the lengthwise direction of the heater
Implementation Method 2
A heater has a first temperature sensor corresponding to a first heating block, a second temperature sensor corresponding to a second heating block
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A control portion determines the lengths of time required to raise a plurality of heat generating elements to prescribed start-up completion target temperatures, and when a heat generating element determined to have the longest start-up requirement time among a plurality of heat generating elements is a second heat generating element, and a heat generating element determined to have shorter start-up requirement time than that of the second heat generating element among a plurality of heat generating elements is a first heat generating element, the control portion controls power to be supplied to the first heat generating element by changing a start-up control parameter for the first heat generating element with reference to the start-up performance of the second heat generating element.