Transfer Belt Unit Tension Control for Curling Prevention
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Solution Overview
Problem
Conventional electrophotographic image forming apparatuses face issues with curling, cracking, and waving of the transfer belt due to inappropriate tension management, leading to increased complexity and cost, as well as potential defects like curling when using materials with high tensile elastic stress.
Innovation Solution
A transfer belt unit with a thickness of 100-200 micrometers, tension of 80-180 N/m, and tensile elastic modulus of 1000-2000 megapascals, combined with a secondary transfer roller of Asker C hardness 35-50 degrees and stretching rollers with an outer diameter of at least 6 millimeters, to maintain optimal belt tension and prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanism that automatically adjusts tension is used to apply appropriate tension during driving and loosen tension during stopping, then curling can be prevented, but the apparatus becomes complicated and cost increases
Solution Approach 1:
The patent extracts the automatic tension adjustment mechanism from the system and replaces it with a simple tensioning roller that applies constant tension. This removes the complex automatic adjustment mechanism while maintaining the essential function of preventing curling through continuous tension application.
Solution Approach 2:
The tensioning roller is designed to automatically maintain appropriate tension on the transfer belt through its own weight and positioning, without requiring external control systems or automatic adjustment mechanisms. The system serves itself by using the inherent properties of the tensioning roller to maintain belt tension.
2Manufacturing precision
If tension is applied at all times to the transfer belt, then accurate secondary transfer is achieved, but deformation of the fixing belt occurs when the apparatus stops
Solution Approach 1:
The patent applies tension locally and selectively - the tensioning roller applies tension only to the transfer belt in the transfer region, while the fixing belt is positioned separately and not subjected to the same tension forces. This local application of tension maintains transfer accuracy without causing fixing belt deformation.
Solution Approach 2:
The patent segments the tension application function, separating the transfer belt tensioning system from the fixing belt system. The tensioning roller specifically targets the transfer belt without affecting the fixing belt, allowing each component to maintain its optimal state independently.
3Reliability
If a material with lower tensile elastic stress is used for the transfer belt, then curling can be prevented, but cracking at the end of the belt or belt waving may occur
Solution Approach 1:
The patent changes the physical parameters of the transfer belt by specifying a thickness range of 100-200 micrometers and a tensile elastic modulus range of 1000-2000 MPa. These parameter changes optimize the belt's mechanical properties to prevent curling while maintaining sufficient strength to resist cracking and waving under the applied tension.
Solution Approach 2:
The patent employs composite material construction for the transfer belt, combining materials with specific mechanical properties that balance flexibility and strength. The composite structure allows the belt to have low enough tensile elastic stress to prevent curling while maintaining adequate strength and rigidity to prevent cracking and waving.
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 reduces curling, cracking, and waving, ensuring high reliability and cost-effectiveness by using thermoplastic elastomer for the transfer belt and metal or urethane rollers, while maintaining excellent image transfer quality.
Implementation Method 1
a toner image formed on a photoconductor as an image carrier is primarily transferred onto an endless transfer belt, and the transferred toner image is carried by endless movement of the transfer belt
Implementation Method 2
curling likely occurs as a tensile elastic stress of material of the transfer belt increases, and the occurrence of curling can be prevented by using a material having a lower tensile elastic stress
Data Source
AI summary
A transfer belt unit satisfies the following conditions. An intermediate transfer belt has a thickness not less than 100 micrometers and not more than 200 micrometers, a tension not less than 80 N/m and not more than 180 N/m, and a tensile elastic modulus not less than 1000 megapascals and not more than 2000 megapascals. A secondary-transfer bias roller has an Asker C hardness not less than 35 degrees and not more than 50 degrees. Stretching rollers for stretching the intermediate transfer belt have an outer diameter not less than 6 millimeters.