Undercoat Layer Adhesion via Surface-Treated Titanium Oxide
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Solution Overview
Problem
Existing electrophotographic photosensitive members face issues with insufficient adhesive strength between the support and the photosensitive layer, leading to peeling and charge accumulation over time, which affects the longevity and stability of the device.
Innovation Solution
Incorporating a polyamide resin and surface-treated titanium oxide particles in the undercoat layer, with a specific volume ratio and particle diameter, along with a thermoplastic resin in the charge generation layer, to enhance adhesive strength and prevent charge accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an undercoat layer with metal oxide particles dispersed in resin is used to suppress charge injection, then image defects such as fogging and leakage are suppressed, but adhesive strength between the support and the photosensitive layer is insufficient for repetitive use
Solution Approach 1:
The patent changes the chemical composition parameters of the undercoat layer by specifying a polyamide resin with particular molecular weight range (5,000-50,000) and using specific surface-treated titanium oxide particles. This parameter optimization resolves the contradiction by achieving both sufficient adhesive strength for repetitive use and effective charge injection suppression, preventing photoensitive layer peeling while maintaining image quality.
Solution Approach 2:
The patent creates a composite undercoat layer combining polyamide resin with surface-treated titanium oxide particles (having specific surface treatment with silane coupling agents). This composite structure provides both the adhesive properties needed to prevent peeling and the charge injection suppression capabilities, resolving the contradiction between strength and reliability.
2Reliability
If conventional undercoat layers are used to suppress charge injection, then image defects are reduced, but charge accumulation occurs due to repetitive use for a long period of time
Solution Approach 1:
The patent optimizes the particle size parameters of titanium oxide (average primary particle diameter 0.01-1.0 μm) and the resin molecular weight parameters to achieve balanced charge management. This resolves the contradiction by preventing charge accumulation during repetitive use while maintaining effective charge injection suppression for image quality.
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 effectively suppresses peeling of the photosensitive layer and reduces charge accumulation, thereby extending the lifespan and stability of the electrophotographic photosensitive member.
Implementation Method 1
As the undercoat layer having low charge accumulation, Japanese Patent Application Laid-Open No. 2009-151329 discloses a technology of using a polyamide resin and surface-treated metal oxide particles
Implementation Method 2
the undercoat layer contains a polyamide resin and a titanium oxide particle which is surface-treated with a compound represented by the following Formula (1)
Data Source
AI summary
An electrophotographic photosensitive member including: a support, an undercoat layer formed above the support, a charge generation layer formed on the undercoat layer, and a charge transport layer formed above the charge generation layer, wherein the undercoat layer contains a polyamide resin and a titanium oxide particle which is surface-treated with a compound represented by Formula (1):when a volume of the titanium oxide particles to a volume of the polyamide resin in the undercoat layer is a, and an average primary particle diameter of the titanium oxide particles is b [μm], the following Equation (A) is satisfied: Equation (A): 14.0≤a/b≤19.1; and the charge generation layer contains a charge generating material and a thermoplastic resin having a hydroxyl group and a hydroxyl number of 50 mgKOH/g or more.