Developing Blade Surface Roughness for High-Speed Imaging
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Solution Overview
Problem
Existing developing blades for electrophotographic imagers, such as laser printers and copiers, face issues with image density and streaks due to high frictional resistance at high speeds, leading to poor image quality.
Innovation Solution
A developing blade with a blade member having a surface shape defined by a maximum height roughness of 0.35 to 4.5 μm and a length ratio under load of 15% or less, manufactured using a method involving sandblasting with abrasives in the range of #150 to #1000, to reduce frictional resistance and ensure uniform toner electrification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the developing roller rotates at high speed to cope with faster operation, then productivity is improved, but frictional resistance increases causing poor image density and streaks
Solution Approach 1:
The invention changes the surface parameters of the blade member by controlling the roughness (Ry: 0.05 to 5.0 μm) and length ratio under load (tp: 20% or less). These parameter changes optimize the friction characteristics between the blade and developing roller, allowing high-speed operation while maintaining reliable toner electrification and preventing image defects.
2Force
If the blade member has smooth surface to reduce friction, then frictional resistance decreases, but toner electrification becomes insufficient
Solution Approach 1:
The invention optimizes the surface roughness parameter (Ry: 0.05 to 5.0 μm) to achieve the optimal balance between friction and electrification. This controlled roughness provides sufficient friction for toner electrification while preventing excessive friction that would cause image defects at high speeds.
Solution Approach 2:
The invention applies a controlled amount of surface roughness (not completely smooth) to achieve the necessary friction for electrification. The partial roughness provides just enough friction for reliable toner pickup and electrification without exceeding the threshold that would cause excessive friction and image defects.
3Reliability
If the blade member has excessive surface roughness to increase friction, then toner electrification improves, but frictional resistance increases causing streaks and poor density
Solution Approach 1:
The invention precisely controls the surface roughness parameter (Ry: 0.05 to 5.0 μm) to prevent excessive friction. This controlled roughness ensures sufficient toner electrification while staying below the threshold that would generate harmful effects like streaks and poor image density during high-speed operation.
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 solution allows for the uniform carrying of toner at high speeds, improving image density and reducing streaks, effectively addressing the limitations of prior art developing blades.
Implementation Method 1
a top mold comprising a mold surface with a cavity formed for formation of a blade member and a gate in communication with said cavity, wherein said cavity is sandblasted with an abrasive in a range of #150 to #1000
Implementation Method 2
a toner in thin layer form is uniformly carried on the peripheral surface of the developing roller 203 by frictional electrification between the developing blade 205 and the developing roller 203
Data Source
AI summary
A developing blade (11) comprises a blade member (14) located along one side edge of a support member (12) and having a surface shape defined by a maximum height roughness Ry of 0.35 to 4.5 μm and a length ratio under load tp (at a 30% cut level) of 15% or less. Such a developing blade is manufactured by bringing a top mold (2) having a mold surface (2A) with a cavity (4) formed for the formation of a blade member and a gate (6) in communication with the cavity (4) in alignment with a bottom mold (3) having a flat mold surface (3A) such that at least a part of the support member (12) is positioned in the cavity (4), clamping together both the top and bottom molds, and pouring a molding material from the gate (6) to fill in the cavity (4).