Transfer Roller Friction Control for Image Forming Apparatus
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Solution Overview
Problem
In image forming apparatuses, metal rollers used as primary transfer rollers tend to slip on intermediate transfer belts, leading to abrasion and a decrease in transfer efficiency due to low friction coefficients, which results in degraded image quality and increased costs from complex bias control or ineffective cleaning methods.
Innovation Solution
The use of metal rollers with elastic bodies at their ends, where the maximum static friction between the roller and the belt is higher than the static friction between the roller's shaft and its bearings, and dynamic friction between the roller and belt is higher than the dynamic friction between the shaft and bearings, prevents slipping and maintains transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a metal roller is used as the primary transfer roller, then the cost of the apparatus is reduced, but the roller slips on the intermediate transfer belt due to low friction coefficient
Solution Approach 1:
The invention uses a composite structure combining a metal roller core with a resin layer having a high friction coefficient. This composite material approach maintains the cost advantage of metal while adding the friction properties needed to prevent slipping on the intermediate transfer belt.
Solution Approach 2:
The resin layer is applied specifically to the surface of the metal roller where contact with the belt occurs. This local modification provides high friction only where needed for belt engagement, while the metal core maintains structural integrity and cost-effectiveness.
2Productivity
If the primary transfer roller slips on the intermediate transfer belt, then abrasion powder is generated and forms a film on the roller, but transfer efficiency decreases and image quality degrades
Solution Approach 1:
The high friction coefficient resin layer is applied in advance to prevent slipping before it occurs. By addressing the root cause of abrasion (slipping), the invention prevents the harmful sequence of abrasion powder generation, film formation, and subsequent transfer efficiency degradation.
3Ease of repair
If cleaning blades are used to remove abrasion powder from the metal roller, then the powder firmly adheres and cannot be effectively removed
Solution Approach 1:
By preventing slipping in the first place through the high friction resin layer, the invention eliminates the source of abrasion powder. This preliminary prevention makes cleaning unnecessary, as no abrasion powder is generated to begin with.
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 maintains stable transfer efficiency and image quality over time by preventing abrasion and the formation of films on the rollers, while reducing costs by eliminating the need for complex bias control and effective cleaning methods.
Implementation Method 1
F1>F3 and F2>F4 are satisfied, where F1 is a maximum static friction between the transfer roller and the endless belt member, F2 is a dynamic friction between the transfer roller and the endless belt member
Data Source
AI summary
An image forming apparatus includes an image carrier; a movable endless belt member forming a nip between the image carrier; and a transfer roller made of metal contacting the belt member at a region corresponding to the nip. At the nip, a toner image on the image carrier is transferred onto the belt member. The transfer roller slidably rotates in bearings supporting its shaft. Members having a higher friction coefficient than that of the transfer roller are provided at end portions of the transfer roller. F1>F3 and F2>F4 are satisfied, where F1 is a maximum static friction between the transfer roller and the belt member, F2 is a dynamic friction between the transfer roller and the belt member, F3 is a maximum static friction between the shaft of the transfer roller and the bearings, and F4 is a dynamic friction between the shaft of the transfer roller and the bearings.