Charge Transporting Film Composition for Electrophotographic Photoreceptors

A dispersant is introduced as an intermediary substance between the fluorine-containing resin particles and the solvent. The dispersant has a hydrophobic group that interacts with the fluorine-containing resin particles and a hydrophilic group that interacts with the solvent, enabling stable dispersion and preventing particle aggregation that would otherwise occur when fluorine-containing resin particles are simply mixed into the surface layer composition.

The invention changes the chemical and physical parameters of the dispersion system by selecting a dispersant with specific molecular structure characteristics (hydrophobic-hydrophilic balance) and controlling its concentration within a specific range (0.1-10 parts by weight per 100 parts of fluorine-containing resin). This parameter optimization ensures adequate particle separation without causing excessive foaming or instability.

The dispersant acts as a mediator that provides steric and electrostatic repulsion between fluorine-containing resin particles. The hydrophobic portions of the dispersant molecules attach to the particle surfaces while the hydrophilic portions extend into the continuous phase, creating a protective barrier that prevents particle aggregation and ensures uniform distribution throughout the surface layer.

The invention optimizes the concentration of the dispersant within a specific range (0.1-10 parts by weight per 100 parts of fluorine-containing resin). This parameter control ensures sufficient particle separation for uniform distribution while avoiding excessive dispersant that could cause foaming, reduce film formation quality, or create new aggregation mechanisms.