Phenol-Aldehyde Polycondensation Toner Charge Control

The patent uses a composite charge controlling agent comprising both phenol type compound and carboxylic acid type compound. The phenol type compound (e.g., polycondensation product of phenols and aldehydes) provides base charging ability, while the carboxylic acid type compound (e.g., polycondensation product of carboxylic acids and aldehydes) enhances the charging amount. This composite approach resolves the contradiction by combining two different chemical systems to achieve both sufficient charging ability and adequate charging amount.

The patent extracts and eliminates the chromium-containing azo dye component from the charge controlling agent system. Instead, it uses chromium-free alternatives such as phenol type compounds and carboxylic acid type compounds. This extraction principle resolves the contradiction by removing the harmful chromatic component while retaining the essential charging function through alternative chemical compounds that do not adversely affect the hue of color toners.

The patent converts the harmful chromium-containing azo dye system into a beneficial chromium-free system. By replacing toxic chromium-based compounds with environmentally friendly phenol type and carboxylic acid type compounds, the invention transforms a harmful charging mechanism into a beneficial one that maintains adequate charging amount while eliminating environmental harm. This principle resolves the contradiction by finding alternative chemical pathways that achieve the same functional goal without the harmful side effects.

The patent optimizes the parameters of the charge controlling agent by carefully selecting the types and ratios of phenol type compounds and carboxylic acid type compounds. By adjusting molecular weight, functional group composition, and relative proportions of different compounds, the invention achieves adequate charging ability while maintaining compatibility with binder resins and good dispersibility. This parameter optimization resolves the contradiction by fine-tuning the chemical characteristics of the charge controlling agent to balance charging performance with compositional stability.