TONER EXTERNAL ADDITIVE, ELECTROSTATIC CHARGE IMAGE DEVELOPING TONER, ELECTROSTATIC CHARGE IMAGE DEVELOPER, TONER CARTRIDGE, PROCESS CARTRIDGE, IMAGE FORMING DEVICE AND IMAGE FORMING METHOD

摘要

Provided is a toner external additive including: a strontium titanate particle which has a hydrophobized surface, in which an average primary particle diameter is 10 nm or more and 100 nm or less, and a specific volume resistivity R1 is 11 or more and 14 or less in terms of a common logarithm value log R1.