Fixation Section Heating Control for Uniform Temperature
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in heating control during startup, leading to uneven temperature distribution and thermal degradation at the fixation section, particularly when the initial temperature is low, and do not effectively manage the transition from heating control modes.
Innovation Solution
The apparatus employs a controller that switches between a first heating mode with a higher temperature changing rate and a second heating mode with a lower rate upon reaching an intermediate target temperature, while rotating the roller, to reduce temperature bias and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the heater is controlled to heat without rotating the pressure roller when initial temperature is low, then heating efficiency is improved, but temperature distribution uniformity deteriorates
Solution Approach 1:
The heating process is divided into multiple stages: a first heating stage where the heater operates without roller rotation to rapidly increase temperature, and a second heating stage where the roller rotates to distribute heat uniformly. This segmentation allows the system to achieve both high heating efficiency and uniform temperature distribution by applying different control strategies at different phases of the heating process.
Solution Approach 2:
The pressure roller is rotated in advance during the second heating stage before the heater is fully deactivated, ensuring that temperature uniformity is established before the heating process concludes. This preliminary action prevents temperature bias from occurring in the final temperature distribution.
2Speed
If the heater is continuously energized to reach final target temperature, then heating speed is improved, but thermal degradation increases
Solution Approach 1:
The heater operates in periodic cycles rather than continuously. During the first heating stage, the heater is energized to rapidly increase temperature. During the second heating stage, the roller rotates to distribute heat while the heater operation is modulated, preventing excessive localized heating and thermal degradation while still achieving the target temperature efficiently.
Solution Approach 2:
The pressure roller acts as an intermediary that redistributes heat across the fixation section. By rotating the roller during the second heating stage, heat is evenly distributed throughout the fixation film and pressure roller, preventing localized overheating and thermal degradation while maintaining overall heating efficiency.
3Stability of the object's composition
If the roller is rotated during high-rate heating, then temperature uniformity is improved, but power consumption increases
Solution Approach 1:
The heating process is segmented into two stages with different roller rotation strategies. During the first heating stage, the roller remains stationary to minimize power consumption while the heater rapidly increases temperature. During the second heating stage, the roller rotates to ensure temperature uniformity. This segmentation ensures that power is consumed for roller rotation only when necessary for temperature distribution, not during the high-power heating phase.
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 ensures uniform temperature distribution, reduces thermal degradation, and minimizes power consumption by adjusting heating control conditions during startup, effectively addressing the bias in temperature distribution and optimizing energy use.
Implementation Method 1
a heating mechanism which heats a recording medium on which a developer is placed to form an image
Implementation Method 2
a temperature detector which detects a temperature of the fixation section
Data Source
AI summary
An image forming apparatus includes: an image forming section; a fixation section having a heating mechanism and a roller arranged to face the heating mechanism; a temperature detector for detecting temperature of the fixation section; and a controller for performing a first heating-control in a first heating mode to raise the temperature of the fixation section at a first changing rate, and a second heating-control in a second heating mode to change the temperature of the fixation section at a second changing rate lower than the first changing rate upon rotating the roller when the temperature of the fixation section has reached an intermediate target temperature. The controller performs the first and second heating-controls, respectively, at the time of startup of the fixation section at least once until the temperature of the fixation section reaches a final target temperature.