Toner, developer including the toner, and method for fixing toner image
A toner composition including toner particles including a binder resin including a modified polyester resin, and a second resin having a weight average molecular weight of from 2,000 to 10,000; a colorant; a release agent; and a particulate material which is present at least a surface portion of the toner particles while embedded into the surface portion, wherein the binder resin has a glass transition temperature not lower than 35° C. and lower than 55° C., and wherein the particulate material has an average particle diameter of from 0.002 to 0.2 times that of the toner particles. A developer including the toner composition and a carrier having a layer thereon which includes at least an acrylic resin and a silicone resin, and a method for fixing an image of the toner composition are also provided.
1. A method for manufacturing a toner comprising toner particles, comprising:
dissolving or dispersing a toner composition, comprising
(i) at least a polyester prepolymer (A) having an isocyanate group, and being capable of reacting with an active hydrogen;
(ii) an amine (B) as a compound having an active hydrogen,
(iii) a second resin having a weight average molecular weight of from 2,000 to 10,000,
(iv) a colorant, and
(v) a release agent, in an organic solvent, to obtain an oil phase liquid;
dispersing the oil phase liquid in an aqueous medium comprising a particulate material while subjecting the polyester prepolymer (A) to an addition polymerization reaction using said compound having said active hydrogen as a cross-linking agent, extending agent or both, to prepare a urea-modified polyester resin and to prepare a dispersion;
removing at least the organic solvent from the dispersion to prepare the toner particles comprising a binder resin which comprises said urea-modified polyester resin and said second resin having a weight average molecular weight of from 2,000 to 10,000;
washing the toner particles; and
drying the toner particles;
wherein said particulate material comprises a particulate resin which is crosslinked;
wherein said binder resin has a glass transition temperature of from 35° C. to below 55° C.;
wherein the particulate material is embedded into the surface of the toner particles;
wherein the particulate material has an average particle diameter of from 0.002 to 0.2 times that of the toner particles.
2. The method according to claim 1 , wherein the particulate material comprises a particulate resin having a glass transition temperature of from 55 to 100° C.
3. The method according to claim 2 , wherein the particulate resin includes a resin selected from the group consisting of vinyl resins, polyurethane resins, epoxy resins and polyester resins.
4. The method according to claim 1 , wherein said binder resin comprises said urea-modified polyester resin and said second resin;
and wherein the binder resin includes tetrahydrofuran-insoluble components in an amount of from 2 to 30% by weight.
5. The method according to claim 1 , wherein the second resin is an unmodified polyester resin, and wherein a ratio of the urea-modified polyester resin to the unmodified polyester resin is from 5/95 to 60/40.
6. The method according to claim 1 , wherein the toner particles have a spindle form.
7. The method according to claim 6 , wherein a ratio (r 2 /r 1 ) of a minor axis particle diameter (r 2 ) of the toner particles to a major axis particle diameter (r 1 ) of the toner particles is from 0.5 to 0.8, and a ratio (r 3 /r 2 ) of a thickness (r 3 ) of the toner particles to the minor axis particle diameter (r 2 ) is from 0.7 to 1.0.
8. The method according to claim 1 , wherein the binder resin comprises tetrahydrofuran-insoluble components in an amount of from 1 to 30% by weight based on total weight of the binder resin.
9. The method according to claim 1 , wherein the release agent is a wax.
10. The method according to claim 1 , further comprising adding an external additive to said toner particles so that said external additive is present at least on a surface of the toner particles.