Developing Agent Carrier Coating for Durability
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Solution Overview
Problem
In electrophotographic systems, the existing developing agents face issues with the longevity of the carrier due to stirring stress, leading to peeling of the surface coating layer and separation of inorganic oxide additives, which affects image quality and durability.
Innovation Solution
A developing agent comprising a carrier with an inorganic oxide external additive coverage of 60% to 120% relative to the core toner and a charging auxiliary particle with positive electrode charge properties and a volume average particle size of 5 to 15 μm, added in an amount of 0.5 to 6% by weight, is used to enhance the stability and adhesion of the toner, thereby reducing the deterioration of the carrier and improving image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the surface coating layer of the carrier is thickened by combining multiple surface treating agents, then the durability of the carrier is improved, but the costs increase, treatment steps become complicated, and the surface coating layer becomes heterogeneous
Solution Approach 1:
The patent combines multiple surface treating agents (silane coupling agent and titanium alkoxide) into a single integrated coating process, achieving both adhesion promotion and surface resistance maintenance without requiring separate treatment steps. This merging approach resolves the contradiction by maintaining carrier durability while simplifying the treatment process.
Solution Approach 2:
The surface coating layer is designed as a composite material incorporating both silane coupling agent and titanium alkoxide, which work synergistically to provide both adhesion strength and appropriate surface resistance. This composite approach allows the coating to maintain durability without requiring excessive thickness or multiple separate treatments.
2Strength
If the external additive is deposited strongly on the core toner to enhance adhesive force, then the adhesion of external additive is improved, but the external additive is buried in the core toner, affecting flow properties or charge properties
Solution Approach 1:
The patent applies local quality by creating a gradient structure where the external additive concentration varies from the core to the surface. The silane coupling agent and titanium alkoxide form a surface layer with optimal adhesion strength while maintaining sufficient exposure of charge-controlling agents, thus achieving both strong adhesion and preserved charge properties.
Solution Approach 2:
The patent optimizes the coverage ratio of external additive to core toner within a specific range (60-120%), which balances adhesion strength and charge properties. By controlling this parameter along with the specific composition of surface treating agents, the patent achieves the desired adhesive force without burying the external additive too deeply.
3Reliability
If the surface coating layer is made thinner to maintain initial carrier surface resistance, then the charge properties are maintained, but the carrier surface resistance decreases over time due to peeling
Solution Approach 1:
The patent applies beforehand cushioning by incorporating silane coupling agent and titanium alkoxide in the surface coating layer before the carrier is put into service. This pre-formed coating structure provides both adhesion strength and appropriate surface resistance, cushioning against future peeling and resistance degradation during the carrier's operational life.
4Strength
If the coverage of inorganic oxide external additive is increased to enhance adhesion, then the adhesive force is improved, but the flow properties of the toner are affected
Solution Approach 1:
The patent precisely controls the coverage ratio of inorganic oxide external additive to core toner within the range of 60-120%, along with optimizing the particle size and surface treatment of the additive. This parameter optimization achieves sufficient adhesive force while maintaining the flow properties necessary for toner performance.
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
This solution effectively prolongs the life of the developing agent by reducing peeling and separation issues, maintaining image quality and durability even after extensive printing, with improved charge stability and flow properties.
Implementation Method 1
The carrier is stirred together with the toner in a developing machine, thereby charging the toner and depositing it onto a photoconductor, etc. due to an electrostatic effect.
Implementation Method 2
charging the toner and depositing it onto a photoconductor, etc. due to an electrostatic effect
Data Source
AI summary
A developing agent includes a carrier; a toner in which an inorganic oxide external additive has a coverage of from 60 to 120% relative to a core toner; and a charging auxiliary particle having charge properties of a positive electrode and having a volume average particle size of from 5 to 15 μm in an addition amount of from 0.5 to 6% by weight relative to the developing agent.