Aqueous pigment dispersion liquid

An aqueous pigment dispersion liquid comprising:

• a pigment;
• a dispersant that disperses the pigment;
• and
• an aqueous medium comprising water,
• wherein the dispersant is a polymer comprising:
• a constitutional unit (A) derived from a monomer (A′);
• and a constitutional unit (B) derived from a monomer (B′) having a carboxy group or an amino group, wherein in the monomer (A′), a group comprising a (meth)acryloyloxy group or a (meth)acryloylamino group is bonded to one end of any one of the following molecular chains of (i) to (iii):
• (i) a polyethylene glycol chain having an average number of repeating oxyethylene units n in a range from 4 to 20;
• (ii) a polyethylene glycol monoalkyl (C1-18) ether chain having an average number of repeating oxyethylene units n in a range from 4 to 9;
• and
• (iii) a molecular chain represented by the following formula (1), the molecular chain having an average number of repeating oxyethylene oxypropylene units n in a range from 20 to 50 and a content of an oxyethylene unit in a range from 70 to 92% by mass:
• R—(OEt)x-(OPr)y-A (1)
• wherein R represents a C1-18 alkyl group, A represents OH or NH2, Et represents an ethylene group, Pr represents a propylene group, and x+y=n,
• a content of the oxyethylene unit derived from the monomer (A′) in the polymer is in a range from 50 to 90% by mass relative to a total mass of the polymer,
• the polymer is (a) an A-B block copolymer or (b) an A-B-A block copolymer, having a polymer block A comprising the constitutional unit (A) and a polymer block B comprising the constitutional unit (B),
• the polymer has a number average molecular weight in terms of polystyrene in a range from 4,000 to 15,000, as measured by gel permeation chromatography,
• the polymer is water-soluble,
• the polymer has a clouding point in a range from 50 to 80° C.,
• the carboxy group or the amino group present in the monomer (B′) and introduced to the polymer is not neutralized and is not ionized in the polymer,
• the aqueous pigment dispersion liquid has a pH in a range from 3.0 to 8.4,
• the polymer adsorbs onto a surface of the pigment in the dispersion liquid, and
• the aqueous pigment dispersion is configured to provide an emulsion-polymerized toner.