Developer Carriers with Controlled Silica Additives
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Solution Overview
Problem
In electrostatic charge image development, the smooth surface of magnetic member dispersing type resin coated carriers leads to increased carrier resistance, causing image defects like deletion at the end of solid images due to silica particles flaking and forming conductive paths between carriers.
Innovation Solution
Incorporating silica particles with a compression aggregation degree of 60% to 95% and a particle compression ratio of 0.20 to 0.40, which enhances their fluidity, dispersivity, and adhesion to toner particles, preventing their flaking and attachment to the carrier surface, thus reducing carrier resistance and image defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a smooth surface carrier is used, then carrier surface uniformity is improved, but carrier resistance increases causing image defects
Solution Approach 1:
The patent applies local quality by adding silica particles specifically to the carrier surface coating layer rather than throughout the entire carrier. This creates a localized rough surface structure only where needed for charge control, while maintaining the smooth core structure for structural integrity. The silica particles are concentrated in the coating layer to provide the necessary surface characteristics without affecting the overall carrier uniformity.
Solution Approach 2:
The patent uses composite materials by combining silica particles with the resin coating layer to form a composite coating. This composite structure provides both the smooth base from the resin and the charge-controlling roughness from the silica particles, resolving the contradiction between surface uniformity and charge resistance control.
2Reliability
If silica particles are added to toner, then toner charge control is improved, but silica particles flake and attach to carrier causing conductive paths
Solution Approach 1:
The patent introduces the resin coating layer as an intermediary between the silica particles and the carrier surface. This coating layer captures and holds the silica particles, preventing them from flaking off and creating conductive paths on the carrier. The intermediary layer thus mediates between the need for silica particles (for charge control) and the need to prevent their harmful effects (flaking).
Solution Approach 2:
The patent applies preliminary action by pre-coating the carrier with a resin layer before adding silica particles. This preliminary coating creates a stable base that prevents silica particle flaking from the outset, rather than attempting to address flaking after it occurs. The coating is applied in advance to establish proper adhesion conditions.
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 specific silica particles with controlled properties ensure uniform attachment to toner particles, reducing flaking and insertion between carriers, thereby preventing image defects and maintaining image quality.
Implementation Method 1
silica particles whose compression aggregation degree is from 60% to 95% and particle compression ratio is from 0.20 to 0.40, which enhances their fluidity
Implementation Method 2
silica particles whose compression aggregation degree is from 60% to 95% and particle compression ratio is from 0.20 to 0.40, which enhances their dispersivity
Implementation Method 3
silica particles whose compression aggregation degree is from 60% to 95% and particle compression ratio is from 0.20 to 0.40, which enhances their adhesion to toner particles
Implementation Method 4
a carrier for developing an electrostatic charge image that has a core including a magnetic member in a binder resin for a core and a coating layer which covers a surface of the core
Data Source
AI summary
An electrostatic charge image developer includes an electrostatic charge image developing toner that includes toner particles, and an external additive which is added to the toner particles and which includes silica particles whose compression aggregation degree is from 60% to 95% and particle compression ratio is from 0.20 to 0.40, and a carrier for developing an electrostatic charge image that has a core including a magnetic member in a binder resin for a core and a coating layer which covers a surface of the core and which includes a resin for a coating layer and has a surface roughness Ra of from 0.25 μm to 0.4 μm.