Urethane Surface Layer Photosensitive Member Abrasion Resistance
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Solution Overview
Problem
Existing electrophotographic photosensitive members experience surface abrasion and contamination leading to non-uniform surface characteristics, resulting in horizontal streak images and density unevenness during long-term use in high-speed and high-print-volume operations.
Innovation Solution
The photosensitive member incorporates a surface layer with a urethane resin and inorganic particles, with a volume ratio of 0.10 to 3.0, and controlled protrusion sizes and roughness to maintain a uniform surface, reducing abrasion and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of printable sheets and printing speed are increased, then productivity is improved, but surface abrasion and contamination increase leading to non-uniform surface characteristics
Solution Approach 1:
The surface layer is constructed as a composite material comprising a binder resin (urethane resin) and inorganic particles (silica, alumina, or titania). This composite structure combines the abrasion resistance of inorganic particles with the binding properties of the urethane resin, creating a surface that maintains uniform characteristics even under high-speed printing conditions with increased abrasion and contamination.
Solution Approach 2:
The patent specifies precise parameter ranges: the volume ratio of inorganic particles to binder resin is controlled at 0.10 to 3.0, the number-based average primary particle diameter of inorganic particles is 10 nm to 500 nm, and the maximum height roughness Rz is 10 nm to 760 nm. These parameter changes optimize the surface layer to resist abrasion while maintaining uniform surface characteristics during high-productivity operation.
2Duration of action of stationary object
If the number of printable sheets is increased, then the lifetime of the photosensitive member is extended, but surface abrasion becomes apparent causing non-uniform surface characteristics
Solution Approach 1:
The inorganic particles in the surface layer have spherical or substantially spherical shapes. This spheroidality allows the particles to roll or slide during abrasion rather than chip or flake, distributing the mechanical stress and preventing localized degradation. The spherical particles maintain surface uniformity over extended printing periods, enabling the photosensitive member to achieve high print volumes while preserving surface characteristics.
Solution Approach 2:
The surface layer combines inorganic particles (silica, alumina, or titania) with a binder resin to create a composite structure that resists abrasion. The inorganic particles provide hardness and wear resistance, while the urethane resin binder maintains surface integrity and uniformity, allowing the photosensitive member to withstand extended use without surface degradation.
3Strength
If inorganic filler is introduced into the surface layer to improve durability, then abrasion resistance increases, but the inorganic filler may locally desorb causing horizontal streak images
Solution Approach 1:
The patent controls the volume ratio of inorganic particles to binder resin within 0.10 to 3.0, which optimizes the balance between abrasion resistance and particle retention. This parameter change ensures sufficient inorganic filler for durability while preventing local desorption that would cause horizontal streak images. The controlled ratio maintains surface uniformity throughout the service life of the photosensitive member.
Solution Approach 2:
The surface layer is designed with specific local properties: the inorganic particles are distributed throughout the urethane resin binder to create a homogeneous composite structure. This local quality ensures uniform abrasion resistance across the entire surface while preventing localized particle desorption that would manifest as horizontal streak images in the output.
4Reliability
If the surface layer is made smoother to reduce friction, then stable rotation is maintained, but abrasion resistance decreases
Solution Approach 1:
The surface layer uses a composite of inorganic particles and urethane resin binder. The inorganic particles provide abrasion resistance while the urethane resin matrix maintains surface smoothness and uniformity. This composite structure achieves both stable rotation through controlled surface properties and resistance to abrasion from the particle-binder combination.
Solution Approach 2:
The patent specifies the maximum height roughness Rz within 10 nm to 760 nm, which optimizes the balance between surface smoothness for stable rotation and abrasion resistance. This parameter control ensures the surface is smooth enough for consistent rotational contact with charging and transfer members while containing enough structural integrity to resist wear during high-volume printing.
Data Source
AI summary
An electrophotographic photosensitive member that can resist mass printing. The electrophotographic photosensitive member is an electrophotographic photosensitive member including a surface layer containing a binder resin and inorganic particles. The surface layer contains a urethane resin as the binder resin, wherein the value of the ratio of the volume of the inorganic particles to the volume of the binder resin in the surface layer is 0.10 or more and 3.0 or less. Protrusions derived from the inorganic particles are present on the surface of the surface layer. The inorganic particles to be incorporated into the surface layer have a number-based average primary particle diameter of 10 nm or more and 500 nm or less. The surface of the surface layer has a maximum height roughness Rz of 10 nm or more and 760 nm or less.