Electrostatic latent image developing toner
An electrostatic latent image developing toner includes a plurality of toner particles each including a core and a shell layer. The shell layer includes a first domain that is a non-crosslinked resin film and second domains that are crosslinked resin particles. The crosslinked resin has a higher glass transition point than the non-crosslinked resin. In a cross-sectional image of a toner particle, a proportion of a total length of a surface region of the core covered by the first domain is at least 45% and no greater than 80% relative to a circumferential length of the core. In a cross-sectional image of a toner particle, a proportion of second domains adhering to a surface of the first domain is at least 30% by number and no greater than 70% by number relative to all the second domains included in the toner particle.
1. An electrostatic latent image developing toner comprising a plurality of toner particles each including a core and a shell layer disposed over a surface of the core, wherein
the shell layer includes at least one first domain having a film shape and second domains each having a particle shape,
the at least one first domain is substantially formed from a non-crosslinked resin and the second domains are substantially formed from a crosslinked resin,
the crosslinked resin has a higher glass transition point than the non-crosslinked resin,
in a cross-sectional image of one of the plurality of toner particles, a proportion of a total length of at least one surface region of the core covered by the at least one first domain is at least 45% and no greater than 80% relative to a circumferential length of the core, and
in a cross-sectional image of one of the plurality of toner particles, a proportion of second domains adhering to a surface of the at least one first domain is at least 30% by number and no greater than 70% by number relative to all the second domains included in the toner particle.
2. The electrostatic latent image developing toner according to claim 1 , wherein
the core has a lower glass transition point than the non-crosslinked resin.
3. The electrostatic latent image developing toner according to claim 2 , wherein
the at least one first domain is fused with the core, and
the second domains are fixed to the core such that a part of each of the second domains is embedded in the core.
4. The electrostatic latent image developing toner according to claim 2 , wherein
the core has a glass transition point of at least 30° C. and no greater than 40° C.,
the non-crosslinked resin has a glass transition point of at least 60° C. and no greater than 90° C., and
the crosslinked resin has a glass transition point of at least 100° C. and no greater than 150° C.
5. The electrostatic latent image developing toner according to claim 4 , wherein
the core contains a non-crystalline polyester resin and a crystalline polyester resin,
the non-crosslinked resin is a polymer of monomers including a styrene-based monomer, a (meth)acrylic acid alkyl ester, and a (meth)acrylic acid hydroxyalkyl ester, and
the crosslinked resin is a polymer of monomers including an acrylic acid-based monomer and a cross-linking agent.
6. The electrostatic latent image developing toner according to claim 5 , wherein
the acrylic acid-based monomer of the crosslinked resin is a (meth)acrylic acid alkyl ester that includes an alkyl group having a carbon number of at least 1 and no greater than 4 in an ester portion thereof, and
the cross-linking agent of the crosslinked resin is a (meth)acrylic acid ester of alkylene glycol.
7. The electrostatic latent image developing toner according to claim 1 , wherein
the at least one first domain and the second domains are layered in the stated order on the surface of the core to form a layered structure.
8. The electrostatic latent image developing toner according to claim 7 ,
in a cross-sectional image of one of the plurality of toner particles, the at least one first domain has an arithmetic mean height of at least 10 nm and less than 50 nm from the surface of the core, and the second domains have an arithmetic mean height of at least 70 nm and no greater than 100 nm from the surface of the core.
9. The electrostatic latent image developing toner according to claim 8 , wherein
the non-crosslinked resin is a polymer of monomers including a styrene-based monomer, a (meth)acrylic acid alkyl ester, and a (meth)acrylic acid hydroxyalkyl ester, and
the crosslinked resin is a polymer of monomers including an acrylic acid-based monomer and a cross-linking agent.
10. The electrostatic latent image developing toner according to claim 9 , wherein
the acrylic acid-based monomer of the crosslinked resin is a (meth)acrylic acid alkyl ester that includes an alkyl group having a carbon number of at least 1 and no greater than 4 in an ester portion thereof, and
the cross-linking agent of the crosslinked resin is a (meth)acrylic acid ester of alkylene glycol.
11. The electrostatic latent image developing toner according to claim 9 , wherein
the at least one first domain is fused with the core, and
the second domains are fixed to the core such that a part of each of the second domains is embedded in the core.