Fixing Device Nip Pressure Control for Curl and Fixation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fixing devices for toner images on transfer paper sheets face challenges in achieving simultaneous satisfactory fixation performance and curl conditions immediately after power-on, due to temperature differences between the fixing roller and pressure roller, which affect warm-up time and environmental conditions.
Innovation Solution
A fixing device with a pressure adjusting unit that changes the nip pressure between the fixing roller and pressure roller based on detected temperatures, allowing for adjustments in surface temperature and temperature differences to optimize fixation performance and curl conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fixing roller is made thick with large heat capacity to ensure fixity, then fixation performance is improved, but warm-up time increases significantly
Solution Approach 1:
The fixing device is divided into three functional rollers: a thin heating roller with heater for rapid temperature increase, a fixing roller with rubber layer for toner fixation, and a pressure roller for applying pressure. This segmentation allows the heating roller to quickly reach operating temperature without requiring the entire fixing assembly to be thick and heat-intensive.
Solution Approach 2:
The thin metal heating roller acts as an intermediary that transfers heat to the fixing roller's rubber layer. This intermediary component enables rapid heating of the critical toner-contact surface without requiring the fixing roller itself to have large heat capacity, thus reducing warm-up time while maintaining fixation performance.
2Force
If the pressure roller is made thick with large heat capacity to ensure pressurizing ability, then pressurizing performance is improved, but temperature difference between fixing roller and pressure roller increases, affecting curl conditions
Solution Approach 1:
The pressure roller is designed with a thin metal core and thin rubber layer, creating local quality differences that enable rapid temperature equalization with the fixing roller. This thin construction allows the pressure roller to quickly reach the same temperature as the fixing roller, reducing temperature differences that cause curling, while still providing sufficient pressurizing force through the rubber layer's elasticity.
3Reliability
If the nip pressure is increased to improve fixation performance, then toner fixation is improved, but temperature difference between rollers increases, worsening curl conditions
Solution Approach 1:
The pressure roller's nip pressure is made dynamically adjustable rather than fixed. This allows the pressure to be optimized for different paper types and environmental conditions, enabling good toner fixation without excessive pressure that would create large temperature differences and curling. The dynamic adjustment capability permits finding the optimal pressure point that balances fixation and curl control.
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 enables simultaneous satisfactory fixation performance and curl conditions without prolonging warm-up time, effectively addressing the temperature and humidity-related issues in existing technologies.
Implementation Method 1
a heat source (4), a fixing roller (2) that is heated by heat provided from the heat source (4)
Implementation Method 2
heat transfer from the fixing roller to the pressure roller is changed
Data Source
AI summary
A pressure lever journaling a pressure roller is rockably connected to a fixation frame journaling a fixing roller. A pivotal position of the pressure lever is adjusted by a motor through driving gears, sector gears, press-contact adjusting levers, and press contact springs, so that a mode of a fixing press contact force is set to a heavy press contact mode or a light press contact mode. By a control section, at start-up immediately after power-on and on basis of a temperature and a humidity detected by a temperature and humidity sensor, the heavy press contact mode is established for rectifying poor curl conditions of paper sheets on condition that the present temperature and humidity environment is a high-temperature high-humidity environment or the light press contact mode is established for rectifying poor fixation performance on condition that the present temperature and humidity environment is a low-temperature low-humidity environment.