Fixing Device Dynamic Pressure Control for Image Quality
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Solution Overview
Problem
Existing image forming devices face challenges in improving the image fixing quality, particularly in ensuring consistent toner melting across varying sheet thicknesses and initial nip temperatures.
Innovation Solution
The fixing device incorporates a sensor unit that outputs a signal corresponding to the continuously changing distance between the heating roller and the pressure roller, allowing the control unit to adjust the fixing pressure dynamically based on sheet thickness and nip temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the fixing pressure is increased to ensure sufficient toner melting for thick sheets, then the image fixing quality improves, but the power consumption and startup time increase
Solution Approach 1:
The patent applies dynamics by making the fixing pressure adjustable rather than fixed. The control unit dynamically changes the fixing pressure based on detected sheet thickness, allowing the system to use higher pressure only when needed for thick sheets, thereby reducing overall power consumption while maintaining image fixing quality.
Solution Approach 2:
The patent changes the parameter of fixing pressure based on sheet thickness detection. By detecting the thickness of each sheet and adjusting the fixing pressure accordingly, the system optimizes power consumption by applying minimal necessary pressure rather than consistently high pressure, thus resolving the contradiction between image fixing quality and power consumption.
2Manufacturing precision
If the fixing pressure is increased to ensure sufficient toner melting for thick sheets, then the image fixing quality improves, but the startup time increases
Solution Approach 1:
The patent applies preliminary action by detecting the sheet thickness before the fixing process begins. This allows the control unit to pre-adjust the fixing pressure to the appropriate level before heating and pressing, eliminating the need for gradual pressure increases during startup and thus reducing startup time while ensuring adequate toner melting.
Solution Approach 2:
The system dynamically adjusts fixing pressure based on real-time sheet thickness detection, allowing rapid optimization of pressing conditions without requiring extended startup periods. This dynamic adjustment enables the system to achieve optimal image fixing quality quickly regardless of sheet thickness variations.
3Adaptability or versatility
If a sensor unit is added to detect sheet thickness and adjust fixing pressure, then the adaptability improves, but the device complexity increases
Solution Approach 1:
The patent implements feedback by using a sensor unit to detect sheet thickness and feeding this information back to the control unit, which then adjusts the fixing pressure accordingly. This closed-loop feedback system enables the device to adapt to varying sheet thickness automatically, improving versatility while keeping the control mechanism integrated and manageable.
Solution Approach 2:
The patent replaces complex mechanical adjustment mechanisms with a sensor-based detection and control system. Instead of requiring manual or mechanically complex adjustable pressing mechanisms, the system uses electronic sensing and control to achieve precise adaptation to different sheet thicknesses, thereby managing device complexity through electronic substitution.
4Manufacturing precision
If the fixing pressure is dynamically adjusted based on sheet thickness, then the image fixing quality improves, but the difficulty of detecting and measuring increases
Solution Approach 1:
The patent introduces a sensor unit as an intermediary between the sheet and the control system. This sensor indirectly detects sheet thickness by measuring parameters such as light transmission or electrical properties, converting physical thickness into an electrical signal that the control unit can process, thereby simplifying the detection and measurement process while maintaining high image fixing quality.
Data Source
AI summary
According to one embodiment, a fixing device includes a first roller, a second roller, and a sensor unit. The first roller is rotatable around a first rotation axis. The second roller is rotatable around a second rotation axis. The second roller can contact and separate from the first roller. The second roller can contact the first roller to form a nip. The distance between the first rotation axis and the second rotation axis is a first distance. The sensor unit can output a signal corresponding to the first distance which is continuously changing.