Toner for developing electrostatic charge image, electrostatic charge image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method

A toner for developing an electrostatic charge image, the toner comprising:

• toner particles containing at least one binder resin;
• a Mg element in an amount such that a net intensity of x-ray fluorescence from the Mg element in the toner is 0.15 kcps or more and 1.15 kcps or less;
• and
• at least one external additive including particles of a metal salt of a fatty acid,
• wherein the binder resin includes an amorphous resin and at least one crystalline resin,
• wherein the toner particles have a volume-average diameter (D50v) of 5 μm or more and 6.5 μm or less,
• wherein the particles of the metal salt of the fatty acid have a volume average particle diameter (D50v) of 1 μm or more and 9 μm or less,
• wherein an amount of the particles of the metal salt of the fatty acid is 0.01 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the toner particles,
• wherein the particles of the metal salt of the fatty acid are at least one selected from the group consisting of particles of zinc stearate, zinc behenate, zinc montanate, and
• wherein in a cross-sectional observation of the toner particles, 90% by number or more of the toner particles meet the following conditions (A) and (C) below, and 70% by number or more of the toner particles meet the following conditions (B1) and (D) below:
• condition (A) that each domain of the crystalline resin has an aspect ratio of 5 or more and 40 or less;
• condition (B1) that each domain of the crystalline resin measures 0.5 μm or more and 1.5 μm or less along a major axis thereof;
• condition (C) that a line extended from the major axis of each domain of the crystalline resin makes an angle of 60° or more and 90° or less with a tangent to a surface of the toner particle at a point of contact between the extended line and the surface;
• and
• condition (D) that lines extended from the major axis of the two domains of the crystalline resin cross each other at an angle of 45° or more and 90° or less.