Heating Roller Temperature Uniformity via Periodic External Contact
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Solution Overview
Problem
In electrophotographic image forming apparatuses, the existing fixing devices face challenges in maintaining uniform temperature of the heating roller, leading to variations in glossiness between images, especially when handling full-color toner images, due to inappropriate timing in the separation of the external heating roller from the heating roller.
Innovation Solution
A fixing device is designed with a control unit that adjusts the timing of the external heating roller's contact and separation from the heating roller based on the type of toner image and the number of sheets being processed, ensuring consistent temperature distribution by setting specific times (t1 and t2) after the paper passes through the nip part, thereby maintaining uniform heat supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the external heating roller is continuously contacted with the heating roller, then the temperature uniformity is improved, but the energy consumption increases and the response time to processing changes decreases
Solution Approach 1:
The external heating roller is moved to contact with the heating roller periodically based on detected processing conditions (such as paper size or color). The control unit determines contact timing and duration, allowing the system to maintain temperature uniformity when needed while reducing energy consumption during normal operation. This periodic contact action enables dynamic adaptation to processing requirements.
2Temperature
If the external heating roller is moved to contact with the heating roller frequently, then the temperature uniformity is improved, but the productivity decreases due to increased movement operations
Solution Approach 1:
The system uses a detection unit to monitor processing conditions (such as paper size, color, or temperature variations) and provides feedback to the control unit. Based on this feedback, the control unit intelligently determines when external heating is necessary, moving the external heating roller to contact with the heating roller only under specific conditions. This feedback mechanism maintains temperature uniformity while minimizing disruptions to productivity.
3Loss of time
If the external heating roller is separated from the heating roller immediately after paper passes, then the response time to processing changes is improved, but the temperature uniformity deteriorates
Solution Approach 1:
The system dynamically adjusts the separation timing of the external heating roller from the heating roller based on detected processing conditions. Rather than using fixed timing, the control unit determines optimal separation moments considering factors such as paper size, color, and temperature distribution. This dynamic adjustment allows the system to respond quickly to processing changes while maintaining temperature uniformity through strategically timed contact periods.
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 solution effectively reduces temperature variations on the heating roller's surface, preventing differences in glossiness between images and ensuring consistent image quality by optimizing the heat transfer process.
Implementation Method 1
The heating member heats the outer circumferential surface of the fixing member
Implementation Method 2
The movement mechanism moves the heating member to contact with and be apart from the fixing member
Implementation Method 3
The pressing member is pressed against an outer circumferential surface of the fixing member to form a fixing pressure part between the pressing member and the fixing member
Data Source
AI summary
A fixing device includes a fixing member, a pressing member, a heating member, a movement mechanism, and a control unit. The fixing member fixes a toner image onto a recording material. The pressing member is pressed against an outer circumferential surface of the fixing member to form a fixing pressure part between the pressing member and the fixing member. The heating member heats the outer circumferential surface of the fixing member. The movement mechanism moves the heating member to contact with and be apart from the fixing member. The control unit controls the movement mechanism to move the heating member relatively apart from the fixing member after a predetermined time elapses after a trailing end of a recording material in a transport direction thereof passes through the fixing pressure part each time when a recording material passes through the fixing pressure part.