Photocurable ink composition and image forming method

A photocurable ink composition comprising:

• a resin which has an amine structure having an α-hydrogen atom and contains at least one selected from the group consisting of an alkylthio group, an alkylenethioalkylene group, and a mercapto group and at least one selected from the group consisting of a fluorinated hydrocarbon group, a polysiloxane group, and a hydrocarbon group having 12 or more carbon atoms;
• at least one of a monofunctional radically polymerizable monomer or a bifunctional radically polymerizable monomer;
• and
• a photopolymerization initiator,
• wherein a weight-average molecular weight of the resin is in a range of 5000 to 30000.