Toner Particle Distribution for Image Sharpness

The patent applies parameter changes by precisely controlling the particle diameter distribution parameters. Specifically, it limits the proportion of coarse particles (8-12 μm) to 5% or less and controls fine particles (5 μm or less) to 30-70%, while optimizing the main particle size range (6-10 μm). This parameter optimization resolves the contradiction by enabling easy development through adequate fine particles while maintaining image sharpness by limiting coarse particles.

The patent applies local quality by creating a specific particle size distribution structure where different particle sizes serve different functions. Fine particles (5 μm or less) provide easy development and fill gaps, while particles in the 6-10 μm range provide sharpness and definition. The restriction on coarse particles (8-12 μm) to 5% or less ensures that local areas of the toner mixture have appropriate properties for both development and sharp image formation.

The patent applies parameter changes by creating a balanced particle size distribution that maintains stable development characteristics over time. By controlling fine particles (30-70%) and limiting coarse particles (5% or less), the toner mixture maintains consistent developability throughout extended use. This prevents the accumulation of difficult-to-develop particles that would otherwise degrade image quality after thousands of copies.

The patent applies continuity of useful action by ensuring that the toner particles maintain their development properties throughout extended use. The specific particle size distribution ensures that both fine and main particles continue to develop effectively over time, preventing the gradual degradation that occurs with conventional toners. This enables continuous high-quality image formation over thousands of copies.