Fatty Acid Metal Salt Developer for Friction Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The combination of amorphous silicon latent image bearing members and elastic blade cleaning units in image forming apparatuses experiences increased friction coefficients over time, leading to toner curling and image defects like voids, and existing lubricant solutions either require additional equipment or result in toner scattering and image fog due to negatively charged fatty acid metal salts.
Innovation Solution
A developer containing a positively chargeable toner and a fatty acid metal salt, specifically zinc, calcium, or magnesium salts of 12-20 carbon atoms, with a particle size distribution of 20% or less for particles ≤3 µm and 5% or less for particles ≥10 µm, is used to suppress friction coefficient increases and prevent toner scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lubricant supply means such as a brush is added to supply lubricant to the latent image bearing member surface, then the friction coefficient increase is suppressed, but the device complexity increases and downsizing is disturbed
Solution Approach 1:
The lubricant supply function is merged with the existing developer system. The fatty acid metal salt, which is already a component of the developer, serves dual purposes: as a development agent and as a lubricant. This eliminates the need for separate lubricant supply means while maintaining friction coefficient stability.
Solution Approach 2:
The developer system serves itself by incorporating the lubricant function within its own composition. The fatty acid metal salt in the developer automatically provides lubrication to the latent image bearing member surface during the normal development process, without requiring external lubricant supply mechanisms.
2Reliability
If fine particles of fatty acid metal salt are used as lubricant, then the friction coefficient increase is suppressed, but the toner charge decreases and toner scattering occurs due to negative charge
Solution Approach 1:
The particle size parameters of the fatty acid metal salt are precisely controlled to resolve the contradiction. By specifying that particles with diameter ≤3 µm constitute 20% by volume or less and particles with diameter ≥10 µm constitute 5% by volume or less, the lubrication effect is maintained while preventing excessive charge neutralization and toner scattering.
Solution Approach 2:
The fatty acid metal salt particles are distributed with specific size characteristics to achieve different functions in different contexts. The controlled particle size distribution ensures that enough fine particles provide lubrication while the majority of larger particles minimize charge interference with the positively chargeable toner.
3Reliability
If fatty acid metal salt is included in the developer, then lubrication is provided, but negatively charged toner generates causing toner scattering and image fog
Solution Approach 1:
Instead of using conventionally negatively charged fatty acid metal salts, the patent employs positively chargeable toner in combination with fatty acid metal salt, inverting the typical charge relationship. This inversion prevents the charge neutralization problem that causes toner scattering and image fog while maintaining the lubrication benefit.
Solution Approach 2:
The developer is formulated as a composite system containing both fatty acid metal salt and positively chargeable toner. This composite material approach allows the fatty acid metal salt to provide lubrication while the positively chargeable toner maintains its charge stability, preventing the formation of reversely charged toner that would cause image defects.
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 maintains a desired toner charge level, reduces image defects such as fog, and prevents toner scattering, while ensuring the elastic blade and toner interact smoothly, thereby improving image quality and apparatus durability.
Implementation Method 1
a fatty acid metal salt... suppress the increase in a friction coefficient at a surface of the latent image bearing member
Implementation Method 2
a positively chargeable toner... maintain a desired charged amount of the toner
Data Source
Figure 1
AI summary
A developer for electrostatic latent image development including a positively chargeable toner and a fatty acid metal salt is used, in which the fatty acid metal salt is a metal salt selected from the group consisting of zinc, calcium, and magnesium salts of fatty acids of 12 to 20 carbon atoms and has a certain volume average particle diameter and particle size distribution.