Developing Roller Surface Layer Anti-Filming Design
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Solution Overview
Problem
Conventional image forming apparatuses experience toner filming due to toner particles and outer additives being attached to the developing roller, leading to poor printing quality.
Innovation Solution
A developing device with a developer supporting member featuring an elastic layer and a surface layer containing carbon black, where the dynamic friction coefficient and ten-point average roughness are optimized to prevent toner particles and outer additives from being attached to the developing roller, thereby preventing toner filming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the developing roller uses a conventional surface layer, then it can support developer effectively, but toner particles and outer additives are attached to the surface causing toner filming
Solution Approach 1:
The patent applies parameter changes by optimizing the dynamic friction coefficient (μ) to 0.05 or less and controlling the ten-point average roughness (Rz) within 1-10 μm for the surface layer. These specific parameter ranges prevent toner particles and outer additives from adhering to the developing roller surface, thereby preventing toner filming while maintaining effective developer support.
Solution Approach 2:
The patent uses composite materials by formulating the surface layer with specific combinations of resin materials and additives that achieve the target dynamic friction coefficient and surface roughness. The surface layer comprises a resin component and a inorganic additive component, creating a composite structure that provides both developer support and anti-adhesion properties.
2Strength
If the surface layer has high friction coefficient, then toner attachment is improved, but toner filming occurs on the developing roller
Solution Approach 1:
The patent applies parameter changes by inverting the conventional approach: instead of using high friction coefficient to improve toner attachment, it uses a very low dynamic friction coefficient (μ≤0.05) combined with controlled surface roughness (Rz: 1-10 μm) to prevent toner filming. The low friction prevents additive adhesion while the surface roughness maintains toner holding capability.
3Quantity of substance
If the surface layer roughness is increased, then toner holding is improved, but outer additives are more likely to be attached
Solution Approach 1:
The patent applies parameter changes by precisely controlling the ten-point average roughness (Rz) within the optimal range of 1-10 μm. This controlled roughness provides sufficient surface area and mechanical interlocking for toner holding while preventing the excessive roughness that would cause outer additive attachment and toner filming.
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
The optimized developing device effectively prevents toner filming, ensuring high-quality printing by regulating the toner layer thickness and maintaining the dynamic friction coefficient within specific ranges, thus enhancing image density and reducing stains and fog.
Implementation Method 1
the surface layer has a dynamic friction coefficient μ between 0.03 and 0.08 (0.03≦μ≦0.08) and a ten-point average roughness Rz (μm) between 1 μm and 10 μm (1≦Rz≦10)
Data Source
AI summary
A developing device includes a developer supporting member having an elastic layer and a surface layer covering the elastic layer for supporting developer; and a developer layer regulating member arranged to abut against the surface layer for regulating a layer thickness of the developer on the surface layer. The surface layer contains at least carbon black. The developer supporting member is configured so that the following equation (1) is satisfied when the surface layer has a dynamic friction coefficient μ between 0.4 and 0.9 (0.4≦μ≦0.9) and a ten-point average roughness Rz (μm) between 2 μm and 6 μm (2≦Rz≦6):2≦C≦0.5×Rz+3 (1)where C is a content of the carbon black (weight parts relative to the surface layer of 100).