Aqueous ink, ink cartridge, ink jet recording method and method for producing aqueous ink

A method for producing an aqueous ink for ink jet containing a resin particle, the method comprising:

• producing a resin particle;
• and
• mixing the resin particle obtained in the producing of the resin particle and other ink components to produce an aqueous ink,
• wherein the producing of the resin particle has
• (1) reacting a polycarboxylic acid with a polyhydric alcohol to synthesize a first resin which is a polyester resin having a carboxylic acid group, and
• (2) in the presence of the polyester resin having a carboxylic acid group and, as necessary, a monomer as a raw material for an acrylic resin,
• (2-1) crosslinking the carboxylic acid group with a compound having both an alkylene oxide group having a repetition number of 1 to 9 and two or more glycidyl groups to synthesize a second resin having a carboxylic acid group, thereby obtaining a resin particle in which the first resin is a polyester resin not having a crosslinked structure and the second resin is at least one of a polyester resin and an acrylic resin having a crosslinked structure, or
• (2-2) polymerizing the monomer as the raw material for the acrylic resin with a monomer having both an alkylene oxide group having a repetition number of 1 to 9 and two or more ethylenically unsaturated bonds to synthesize a second resin having a carboxylic acid group, thereby obtaining a resin particle in which the first resin is a polyester resin not having a crosslinked structure and the second resin is an acrylic resin having a crosslinked structure.