Fixing Roller Hardness and Velocity Differential for Toner Offset
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Solution Overview
Problem
Existing external heating type fixing apparatuses in image forming devices face issues with toner and paper dust contamination, where offset toner and paper dust adhere to the fixing roller, leading to defective images due to insufficient adhesion differences between the fixing roller and rotator, and between the contamination and heating/pressing films.
Innovation Solution
The fixing apparatus incorporates a heating unit with a film and a pressing unit, where the micro hardness of the roller's surface is lower than the film's at the heating portion, and velocity differences are created between the roller and film surfaces to prevent contamination from moving to the heating unit, while ensuring effective adhesion to the pressing unit for discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the adhesion of offset toner to the fixing roller is made stronger than to the rotator, then offset toner remains on the fixing roller, but contamination (mixture of offset toner and paper dust) may still move to the rotator due to weak adhesion of contained toner
Solution Approach 1:
The invention changes the surface hardness parameter of the fixing roller to be softer than both the heating film and pressing film. This parameter modification creates selective adhesion where contamination adheres to the softer fixing roller during heating, preventing transfer to the rotator while maintaining effective discharge through the pressing unit.
Solution Approach 2:
The invention applies preliminary action by having the heating film transfer contamination to the fixing roller before the contamination can naturally move to the rotator. This proactive contamination management prevents image defects by ensuring contamination is captured and discharged through the pressing unit rather than transferring to subsequent components.
2Use of energy by moving object
If a heating film is used to heat the fixing roller, then heating efficiency is improved, but contamination may adhere to the heating film and transfer to subsequent recording materials
Solution Approach 1:
The invention modifies the surface hardness parameter of the heating film to be harder than the fixing roller. This creates a hardness gradient where the softer fixing roller preferentially adheres contamination, while the harder heating film resists contamination adhesion and facilitates contamination transfer to the fixing roller for discharge.
Solution Approach 2:
The fixing roller acts as an intermediary between the heating film and the rotator. It captures contamination from the heating film through selective adhesion and transfers it to the pressing film for discharge, preventing direct contact between contamination and subsequent recording materials while maintaining heating efficiency.
3Reliability
If the micro hardness of the roller surface is made lower than the film surface, then contamination adhesion to the roller is enhanced, but the roller surface may wear faster
Solution Approach 1:
The invention optimizes the surface hardness parameter of the fixing roller to be softer than the films but within a range that balances adhesion performance and wear resistance. This parameter optimization ensures contamination is effectively captured while maintaining adequate service life through controlled wear characteristics.
Solution Approach 2:
The fixing roller is constructed as a composite structure with a softer surface layer that provides selective adhesion for contamination capture, while the underlying structure maintains structural integrity and wear resistance. This composite approach allows the surface to be softer for better contamination control while the bulk material ensures durability.
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 contamination from transferring to the heating unit, maintaining image quality by ensuring contamination adheres to the pressing unit for discharge, reducing defects and maintaining image quality even after printing large volumes.
Implementation Method 1
a heating unit configured to be in contact with the roller to form a heating portion with the roller, and heat the roller via the heating portion
Implementation Method 2
a velocity difference is provided between the surface of the roller and the surface of the film
Data Source
AI summary
A fixing apparatus that heats, at a nip portion, a recording material, bearing a toner image, while conveying the recording material to fix the toner image thereto, includes a roller, a heating unit configured to contact the roller to form a heating portion with the roller, and heat the roller via the heating portion, wherein the heating unit includes a film, and a heating portion forming member configured to contact an inner surface of the film and form the heating portion with the roller via the film, and a backup member configured to contact the roller and form the nip portion with the roller. A micro hardness of a surface of the roller is lower than that of the film at the heating portion, and in at least a partial region of the heating portion, a velocity difference is provided between the surfaces of the roller and the film.