Developing Roller Surface Glossiness and Bead Spacing
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Solution Overview
Problem
Electrophotographic image forming apparatuses using polymerized toner face challenges in extending lifespan due to filming of the developing roller, which affects image quality and durability, and existing solutions like increasing the nip between rollers or using low surface energy coatings are either costly or ineffective in preventing filming.
Innovation Solution
An electrophotographic image forming apparatus with a developing roller having a surface glossiness of 4 to 15 and protruding beads with a specific average distance, combined with a supplying roller featuring foam cells of a certain size and rotation velocity, improves the resetting performance of the developing roller, effectively preventing filming and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the nip between the developing roller and the supplying roller is increased or the hardness of foam of the supplying roller is increased to improve resetting performance, then the resetting performance improves, but stress applied to the toner increases causing image quality degradation
Solution Approach 1:
The patent changes the physical and chemical parameters of the developing roller surface by controlling glossiness (4-15) and incorporating protruding beads with specific spacing (Rsm: 200-400 μm). These parameter changes modify the surface properties to reduce toner adhesion without increasing mechanical stress, thereby improving resetting performance while maintaining image quality.
Solution Approach 2:
The patent applies local quality by creating protruding beads at specific locations on the developing roller surface with controlled spacing (Rsm: 200-400 μm). This localized structural modification provides targeted resetting action at bead locations while maintaining gentler conditions in other areas, reducing overall stress on toner particles.
2Reliability
If a coating solution containing fluorine resin is used to coat the developing roller surface to improve fouling resistance, then the manufacturing cost increases and reverse polarity toner problems occur, but filming is not significantly reduced
Solution Approach 1:
The patent replaces expensive fluorine resin coatings with a cost-effective alternative: controlling the glossiness (4-15) and adding protruding beads to the developing roller surface. This approach achieves similar fouling resistance without the high manufacturing costs and compatibility issues of fluorine-based coatings.
Solution Approach 2:
The patent changes the surface parameters of the developing roller by controlling glossiness (4-15) and incorporating protruding beads with specific spacing (Rsm: 200-400 μm). These parameter changes provide fouling resistance through physical surface characteristics rather than chemical coatings, avoiding the costs and complications of fluorine resin application.
3Reliability
If the surface of the developing roller is coated with low surface energy resin to improve resetting performance, then manufacturing cost increases and background contamination occurs, but filming is not significantly reduced
Solution Approach 1:
The patent applies local quality by creating protruding beads at specific locations on the developing roller surface with controlled spacing (Rsm: 200-400 μm). This localized structural modification provides targeted resetting action at bead locations while maintaining gentler conditions in other areas, reducing overall stress on toner particles and preventing background contamination.
Solution Approach 2:
The patent changes the surface parameters of the developing roller by controlling glossiness (4-15) and incorporating protruding beads with specific spacing (Rsm: 200-400 μm). These parameter changes provide resetting performance through physical surface characteristics rather than chemical coatings, avoiding the background contamination issues associated with low surface energy resins.
Data Source
AI summary
An electrophotographic image forming apparatus has a developing roller, wherein a glossiness of a surface of the developing roller is in a range of about 4 to about 15, the developing roller includes a plurality of protruding beads, a number average distance (Rsm) between the protruding beads is in a range of about 200 μm to about 400 μm, a supplying roller includes a plurality of foam cells, a number average size of the foam cells is in a range of about 300 μm to about 500 μm, and the developing roller is arranged to rotate at a rotation linear velocity that is about 120% to about 150% of a rotation linear velocity of a photoreceptor.