Pressure Roller Outer Diameter Profile for Fixing Device Wrinkle Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fixing devices in image forming apparatuses often experience temperature unevenness due to the arrangement of resistive heat generators, leading to reduced heat generation in separation areas and subsequent wrinkles in heated sheets.
Innovation Solution
The implementation of a pressure roller with a specific outer diameter profile that compensates for thermal expansion differences across the fixing device, ensuring consistent force application and preventing wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the outer diameter of the pressure roller is increased from the center to both ends in the axial direction, then the force applied to the sheet prevents wrinkle occurrence at the edges, but temperature unevenness in the separation area causes thermal expansion differences that reduce the effectiveness of wrinkle prevention
Solution Approach 1:
The pressure roller is designed with a non-uniform outer diameter profile where specific regions (first and third regions) have different increasing rates from the center toward the ends. This local variation in geometry compensates for the local temperature unevenness in the separation area, ensuring that the pressure distribution adapts to the thermal expansion differences and maintains effective wrinkle prevention across the entire sheet width.
Solution Approach 2:
The outer diameter of the pressure roller is deliberately designed to change at different rates in different axial regions. The first region has a first increasing rate and the third region has a second increasing rate, creating a parameter variation that compensates for thermal expansion effects. This parameter change allows the pressure roller to maintain consistent contact pressure despite temperature variations in the separation area.
2Force
If the pressure roller has a larger outer diameter at the ends to apply greater force, then edge wrinkles are prevented, but the temperature decrease in the separation area causes insufficient thermal expansion to maintain the desired pressure distribution
Solution Approach 1:
The pressure roller incorporates local quality variations through its non-uniform outer diameter profile. The first and third regions have different increasing rates compared to the second region, creating localized pressure characteristics that compensate for temperature-induced thermal expansion differences. This ensures reliable and consistent pressure distribution across regions with varying temperatures.
Solution Approach 2:
The pressure roller's geometry is pre-designed to anticipate and counteract the thermal expansion differences that occur during operation. By creating regions with different increasing rates before heating occurs, the system pre-compensates for the temperature decrease in the separation area, maintaining reliable pressure distribution without requiring active control during the fixing process.
3Temperature
If the pressure roller is designed with different increasing rates in different regions, then thermal expansion differences are compensated, but the manufacturing complexity of the pressure roller increases
Solution Approach 1:
The pressure roller is manufactured with local quality variations in its outer diameter profile. By dividing the roller into regions with different increasing rates, the design achieves thermal expansion compensation while using conventional manufacturing techniques to create the non-uniform geometry, balancing performance requirements with manufacturing feasibility.
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 configuration effectively prevents wrinkles in heated sheets by maintaining consistent thermal expansion and force distribution across the pressure roller, thereby enhancing the reliability of the fixing process.
Implementation Method 1
a heater as a heating body that includes a plurality of resistive heat generators arranged in the longitudinal direction of the heater and separated from each other
Implementation Method 2
the temperatures of the fixing belt and the pressure roller also decrease at positions corresponding to the separation area
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
A heating device (9) includes a heater (22), a rotator (20), and a pressure rotator (21). The heater (22) includes resistive heat generators (31) forming a heat generation area (C) and has a separation area (B) formed by the resistive heat generators (31). The pressure rotator (21) includes a region (J1) and a region (J2). The region (J2) includes a position corresponding to the separation area (B) and faces the heater (22) in a part of a range from a center (B0) of the area (B) to a center (C0) of the area (C). The region (J1) is nearer to a position facing the center (C0) on the pressure rotator (21) than the region (J2). The outer diameter of the region (J1) increases at an increasing rate smaller than an increasing rate of the outer diameter of the region (J2) from the center (C0) toward an end of the area (C).