Titanium oxide is known to reduce toner charge levels and particularly helps lower the charge ratio under HH/LL environments. However, it has recently been classified as a potential carcinogen. As an alternative, Sukgyung’s SnO₂ and SiO₂@SnO₂ maintain similar charge control properties while offering improved toner dispersibility and flowability due to their lower particle density. These materials are low in human toxicity, environmentally friendly, and free from heavy metal concerns, making them well-suited for global regulatory compliance. In particular, SiO₂@SnO₂, with a large particle size of 100 nm, serves both as a spacer and a charge reducing agent, offering excellent performance. Customized surface treatments and particle size adjustments allow for flexible application in various toner formulations.