1. An aqueous dispersion, comprising:
a gel particle which has a polymerizable group, has a three-dimensional cross-linked structure comprising at least one kind of bond selected from a urethane bond and a urea bond, and comprises a photopolymerization initiator in the interior of the gel particle;
a resin; and
water.
2. The aqueous dispersion according to claim 1,
wherein the photopolymerization initiator comprises at least one of a carbonyl compound or an acylphosphine oxide compound.
3. The aqueous dispersion according to claim 1 or 2,
wherein the gel particle has a hydrophilic group on a surface of the gel particle.
4. The aqueous dispersion according to any one of claims 1 to 3,
wherein the gel particle comprises a polymerizable monomer in the interior of the gel particle.
5. The aqueous dispersion according to any one of claims 1 to 4,
wherein the gel particle comprises a sensitizer in the interior of the gel particle.
6. The aqueous dispersion according to any one of claims 1 to 5,
wherein the resin has at least one kind of structure selected from the group consisting of a polyester structure, a polyurethane structure, and a polyolefin structure.
7. The aqueous dispersion according to any one of claims 1 to 6,
wherein a content of the resin with respect to a total amount of a solid content of the gel particle is 1% by mass to 110% by mass.
8. The aqueous dispersion according to any one of claims 1 to 7,
wherein a content of the resin with respect to a total amount of a solid content of the

9. The aqueous dispersion according to any one of claims 1 to 8,
wherein a total amount of a solid content of the gel particle with respect to a total amount of the aqueous dispersion is 1% by mass to 50% by mass.
10. A method for manufacturing the aqueous dispersion according to any one of claims 1 to
9, the method comprising:
a preparation step of preparing a gel particle dispersion comprising the gel particle and water; and
a resin mixing step of mixing the gel particle dispersion with the resin to obtain the aqueous dispersion.
11. The method for manufacturing the aqueous dispersion according to claim 10,
wherein the preparation step comprises:
an emulsification step of obtaining an emulsion by mixing and emulsifying any one oil-phase component selected from an oil-phase component comprising the photopolymerization initiator, an isocyanate compound having three or more functional groups, a polymerizable monomer, and an organic solvent, an oil-phase component comprising the photopolymerization initiator, a polymerizable group-containing isocyanate compound having three or more functional groups, and an organic solvent, and an oil-phase component comprising the photopolymerization initiator, a polymerizable group-containing isocyanate compound having three or more functional groups, a polymerizable monomer, and an organic solvent, with a water-phase component comprising water; and
a gelification step of obtaining a gel particle dispersion comprising a gel particle and water by heating the emulsion.
12. The method for manufacturing the aqueous dispersion according to claim 11,
wherein the isocyanate compound having three or more functional groups in the oil-phase component is an isocyanate compound derived from at least one kind of compound selected from isophorone diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, l,3-bis(isocyanatomethyl)cyclohexane, m-xylylene diisocyanate, and dicyclohexylmethane 4,4'-diisocyanate.

13. An image forming method, comprising:
an application step of applying the aqueous dispersion according to any one of claims 1 to 9 onto a recording medium; and
an irradiation step of irradiating the aqueous dispersion applied onto the recording medium with an active energy ray.