Developing Roll Surface Layer Chemical Binding Prevents Ion Blooming
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Solution Overview
Problem
Conventional developing rolls for electrophotographic machines face issues with ion conductive agent blooming and reduced charge retention due to hydrophilic properties, leading to uneven image density and decreased charged-electric quantity, especially under high humidity conditions.
Innovation Solution
A developing roll with a surface layer containing a binder resin chemically bound to an ion conductive agent featuring a specific cation structure (R1-N+—R2-Si(OR3)3, where R1 is a cyclic or linear organic group, R2 contains at least (CH2)n, and R3 is an alkyl group, and the anion is bis(trifluoromethanesulfonyl)imide (TFSI), which prevents blooming and maintains charge decay characteristics over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the content of the ion conductive agent is increased in the functional layer, then the charging property is improved and horizontal stripe unevenness is prevented, but the ion conductive agent blooms causing image unevenness and image contamination
Solution Approach 1:
The patent introduces a coupling agent as an intermediary substance between the ion conductive agent and the binder resin. This coupling agent chemically bonds to both the ion conductive agent and the binder resin, preventing the ion conductive agent from blooming while maintaining its charging function. The coupling agent acts as a bridge that secures the ion conductive agent in place without compromising its electrical properties.
Solution Approach 2:
The patent creates a composite functional layer structure consisting of binder resin, ion conductive agent, and coupling agent. This composite material system combines the adhesive properties of the binder resin with the conductive properties of the ion conductive agent, while the coupling agent ensures stable integration between these components, preventing blooming and maintaining uniform charge distribution.
2Reliability
If the ion conductive agent with hydrophilic properties is used, then the conductive property is provided, but the charge retention characteristics are decreased under high humidity environment
Solution Approach 1:
The coupling agent serves as a hydrophobic intermediary between the hydrophilic ion conductive agent and the binder resin. This coupling agent protects the ion conductive agent from direct contact with moisture in the high humidity environment, preventing water from affecting the charge retention characteristics while allowing the ion conductive agent to maintain its conductive function.
Solution Approach 2:
The patent changes the chemical parameters of the functional layer by introducing the coupling agent with specific chemical structure that provides hydrophobicity. This parameter change modifies the interaction between the ion conductive agent and the high humidity environment, reducing water absorption and maintaining stable charge retention characteristics.
3Ease of manufacture
If the ion conductive agent is merely dispersed in the binder resin without chemical binding, then the manufacturing is simple, but the ion conductive agent blooms when content is increased
Solution Approach 1:
The coupling agent acts as a chemical intermediary that creates stable bonds between the ion conductive agent and the binder resin. This chemical bonding through the coupling agent prevents the ion conductive agent from blooming even when its content is increased, while still maintaining a relatively simple manufacturing process compared to direct chemical synthesis methods.
Solution Approach 2:
The patent replaces the simple physical dispersion method with a chemical bonding method using the coupling agent. This substitution transforms the mechanical mixing process into a chemical bonding process, providing stable composition and preventing blooming while maintaining ease of manufacture through a straightforward coating and curing process.
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 chemical binding of the ion conductive agent to the binder resin prevents blooming and ensures consistent charge retention, achieving uniform image density and sufficient charged-electric quantity even in high humidity environments.
Implementation Method 1
a (B) ingredient that defines an ion conductive agent that contains a cation having a chemical structure represented by the following general formula (1), wherein the cation in the (B) ingredient is bound with the (A) ingredient
Data Source
AI summary
Provided is a developing roll for use in an electrophotographic machine capable of preventing an ion conductive agent from blooming and retaining long-term charge decay characteristics. The roll (1) includes a shaft (2), an elastomeric layer (3) and a surface layer (4), wherein the surface layer contains a composition containing an (A) ingredient defining a binder resin having a functional group reactive with an alkoxy silyl group in a (B) ingredient, and the (B) ingredient defining an ion conductive agent containing a cation having a chemical structure represented by R1-N+-R2-Si(OR3)3, where R1: a cyclic organic group or a linear organic group, R2: a group containing at least (CH2)n, n representing an integer number, and R3: an alkyl group, wherein the cation is bound with the (A) ingredient, and wherein the (B) ingredient is 0.10 to 3 parts by mass with respect to 100 parts by mass of the (A) ingredient.