Image Forming Apparatus Power Control for Temperature Stability
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining uniform temperature control during the heating process, leading to uneven toner melting and image glossiness issues due to the delay in power correction timing relative to the entry of recording materials into the heat nip portion, particularly with wave number control methods.
Innovation Solution
Implementing a hybrid power control method that switches from wave number control to phase control before the recording material enters the heat nip, allowing for precise power correction timing to match the entry point, thereby minimizing temperature fluctuations and ensuring consistent image glossiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wave number control method is used for power supply control, then device complexity is reduced and ease of operation is improved, but temperature control precision deteriorates leading to temperature ripples and uneven toner melting
Solution Approach 1:
The power supply control is segmented into two distinct control methods: wave number control for general operation and phase control for precise temperature maintenance. The controller switches between these two methods based on operational requirements, thereby combining the simplicity of wave number control with the precision of phase control without permanently increasing system complexity.
Solution Approach 2:
The control system dynamically switches between wave number control and phase control modes. The controller monitors temperature and operational state, automatically selecting wave number control when simplicity is sufficient and phase control when precise temperature maintenance is required, making the system adaptable to different operational demands.
2Speed
If power correction timing is delayed relative to recording material entry, then response time is reduced, but temperature uniformity deteriorates causing uneven brightness and glossiness
Solution Approach 1:
The controller performs preliminary action by detecting the leading edge of the recording material and calculating the precise timing for power correction in advance. The power correction is applied at the optimally timed moment before or during material entry, ensuring temperature uniformity without excessive delay. This preliminary detection and calculation enable precise timing control.
3Stability of the object's composition
If wave number control with prolonged revising cycle is used, then power supply stability is improved, but timing precision for power correction deteriorates
Solution Approach 1:
The control cycle is segmented into different phases: the wave number control operates with its prolonged revising cycle for general stability, while the phase control operates with precise timing for power correction. This segmentation allows each control method to operate in its optimal regime without compromise.
Solution Approach 2:
The controller acts as an intermediary that bridges the prolonged revising cycle of wave number control and the precise timing requirements of phase control. It monitors the recording material entry and triggers phase control at the appropriate moment within the wave number control cycle, thereby reconciling the timing precision requirement with the stability of the prolonged cycle.
4Manufacturing precision
If phase control is used for power correction, then temperature control precision is improved, but harmonic currents increase affecting power supply quality
Solution Approach 1:
The power supply control is segmented into two distinct control methods: wave number control for general operation and phase control for precise temperature maintenance. The controller switches between these two methods based on operational requirements, thereby combining the simplicity of wave number control with the precision of phase control without permanently increasing system complexity.
Solution Approach 2:
The system uses periodic wave number control as the baseline operation and applies phase control periodically only when precise temperature correction is needed. This periodic application of phase control minimizes the generation of harmonic currents while maintaining temperature precision when required, rather than continuously applying phase control.
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 reduces temperature ripples and harmonic currents, achieving stable temperature control and improved image quality by aligning power correction with the exact timing of the recording material's entry, thus preventing hot offsets and uneven brightness.
Implementation Method 1
a heating element (heat source) 16, and a pressure member 22... the visible image bearing surface of the recording material is accordingly heated by the heating element through the film to fix a visible image by heat
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The image forming apparatus includes a fixing portion, a temperature detection element, and a power control portion, wherein the power control portion is capable of setting a first power supply control mode for supplying power according to the detected temperature for each one control cycle, a second power supply control mode for supplying power according to the detected temperature for each one control cycle and a third power supply control mode for supplying predetermined power, and switches, immediately before a leading edge of the recording material enters the fixing portion, a state of supplying the power in the first power supply control mode to a state of supplying the power in the second power supply control mode, and then switches the state of supplying the power in the second power supply control mode to a state of supplying the power in the third power supply control mode.