Magnetic toner for developing electrostatic latent image

摘要

A magnetic toner for developing an electrostatic latent image of the present disclosure includes toner particles each having a toner core containing a binder resin and a magnetic powder, and a shell layer coating a surface of the toner core. The shell layer contains a unit derived from a monomer of a thermosetting resin and a unit derived from a thermoplastic resin. The thermosetting resin is one or more resins selected from the group of amino resins consisting of a melamine resin, a urea resin, and a glyoxal resin. The amount of iron eluted from the toner core (iron concentration in a filtrate) measured by a specified method is 10 mg/L or less.

主权项

1. A magnetic toner for developing an electrostatic latent image, comprising toner particles each having a toner core containing a binder resin and a magnetic powder, and a shell layer coating a surface of the toner core, wherein
the shell layer contains a unit derived from a monomer of a thermosetting resin and a unit derived from a thermoplastic resin, the thermosetting resin is one or more resins selected from the group of amino resins consisting of a melamine resin, a urea resin, and a glyoxal resin, and an amount of iron eluted from the toner core is 10 mg/L or less, the amount of iron eluted from the toner core being measured through: keeping 2 g of the toner core suspended at 60° C. for 6 hours in 50 mL of an aqueous solution of benzohydroxamic acid having a pH adjusted to 4 and a concentration of 2% by mass to obtain a suspension; filtering the suspension containing the toner core to obtain a filtrate; measuring an absorbance of the filtrate for a light beam having a wavelength of 440 nm; and measuring the amount of iron eluted from the toner core as an iron concentration in the filtrate based on the absorbance with a standard curve.