Electrostatic latent image developer, developing apparatus, image forming apparatus and image forming method
View Patent ↗An electrostatic latent image developer contains: an electrostatic-latent-image-developing toner that has toner particles formed by aggregating and fusing particles of a polyester resin, particles of a styrene resin and particles of a coloring agent in a starting material dispersion liquid of those particles dispersed in an aqueous solvent; and a carrier having a core particle and a resin coating layer to coat the surface of the core particle, wherein the ratio of the exposed area of the core particle to the surface of the carrier is about 7% or less.
1. An electrostatic latent image developer comprising:
an electrostatic-latent-image-developing toner that has toner particles formed by aggregating and fusing resin particles containing a polyester resin and a styrene resin and particles of a coloring agent in a starting material dispersion liquid of those particles dispersed in an aqueous solvent; and
a carrier having a core particle and a resin coating layer coating the surface of the core particle,
wherein the ratio of the exposed area of the core particle to the surface of the carrier is about 7% or less, and
wherein the weight-average molecular weight (Mw) of the polyester resin is from about 12,000 to about 200,000.
2. The electrostatic latent image developer according to claim 1 , wherein the glass transition temperature of the polyester resin is from about 30° C. to about 90° C.
3. The electrostatic latent image developer according to claim 1 , wherein the total content of the polyester resin and the styrene resin is from about 70% by mass to about 95% by mass, relative to the entire toner particles.
4. The electrostatic latent image developer according to claim 1 , wherein the ratio by mass of the polyester resin to the styrene resin (polyester resin/styrene resin) is from about 10/90 to about 50/50.
5. The electrostatic latent image developer according to claim 1 , wherein the resin contained in the resin coating layer contains a cycloalkyl (meth)acrylate as the polymerization component thereof.
6. The electrostatic latent image developer according to claim 5 , wherein the cycloalkyl (meth)acrylate is cyclohexyl methacrylate.
7. The electrostatic latent image developer according to claim 1 , wherein the polyester resin contains bisphenol A as the polymerization component thereof.
8. The electrostatic latent image developer according to claim 1 , wherein the coloring agent contains C.I. Pigment Yellow 74.
9. The electrostatic latent image developer according to claim 1 , wherein the volume electric resistance (volume resistivity) of the core particle is from about 10 5 Ω·cm to about 10 9.5 Ω·cm.
10. The electrostatic latent image developer according to claim 1 , wherein the mean thickness of the resin coating layer is from about 0.1 μm to about 10 μm.
11. The electrostatic latent image developer according to claim 1 , wherein the weight-average molecular weight of the resin contained in the resin coating layer is from about 5,000 to about 1,000,000.
12. The electrostatic latent image developer according to claim 1 , wherein the volume electric resistance (at 25° C.) of the carrier is from about 1×10 7 Ω·cm to about 1×10 15 Ω·cm.