Fixing Device Press Roller Speed Control for Thermal Expansion
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses face challenges in maintaining consistent image fixation due to temperature and sheet type variations, leading to unstable transport speeds and potential issues like streaks or wrinkles, especially when the press roller expands with heat.
Innovation Solution
A control device that adjusts the rotation speed of the press roller based on the fixing element's temperature, sheet type, and ambient conditions, using correction values to maintain a consistent transport speed by accounting for thermal expansion, thereby preventing fluctuations in sheet transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the press roller rotates at a constant speed, then the device structure is simple, but the transport speed becomes unstable when the fixing element temperature varies, causing streaks or wrinkles
Solution Approach 1:
The control device measures the temperature of the fixing element and uses this feedback to dynamically adjust the press roller rotation speed. The controller calculates a correction value based on the temperature deviation from target and applies it to the rotation speed command, creating a closed-loop control system that maintains stable transport speed despite temperature variations.
Solution Approach 2:
The system changes the rotation speed parameter of the press roller based on the fixing element temperature. By adjusting this operational parameter in response to temperature measurements, the system compensates for thermal expansion effects and maintains consistent sheet transport speed without requiring mechanical structural changes.
2Reliability
If the press roller rotation speed is increased to compensate for thermal expansion, then the transport speed stability improves, but the risk of sheet transport issues increases
Solution Approach 1:
The control device continuously monitors fixing element temperature and adjusts press roller speed accordingly. By using feedback control with calculated correction values, the system achieves precise speed compensation that prevents both under-compensation (which would cause streaks) and over-compensation (which would cause transport defects), maintaining optimal transport speed consistency.
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 ensures stable image fixation by maintaining a consistent transport speed, preventing streaks and wrinkles, without complicating the device structure, by dynamically adjusting the press roller's rotation speed in response to temperature and sheet characteristics.
Implementation Method 1
The heat source heats a circumferential surface of the fixing element
Implementation Method 2
the press roller expands with heat
Data Source
AI summary
A fixing device includes: a fixing element; a heat source heating the fixing element; a press roller pressed against the fixing element, to form with the fixing element a nip region where a recording sheet passes; a driver device rotating the press roller; and a controller controlling the heat source to set a temperature of the fixing element to a predetermined target temperature, and controlling the driver device to set a rotation speed of the press roller to a predetermined target rotation speed. The controller determines the target rotation speed by adding a correction value to a normal rotation speed, based on the temperature of the fixing element at start of job, a type of the recording sheet, ambient temperature, and elapsed time from start of paper feed, and sets the rotation speed of the press roller to the target rotation speed.