Technical Field
The present invention relates to an ink composition for inkjet printing, an ink set, and an image formation method.
Related Art
As an ink composition for inkjet printing (hereinafter, also simply referred to as the “ink”) used in an image forming method by an inkjet method, a water-based ink using water as a solvent draws attention besides a solvent-based ink using a solvent as a solvent in consideration of the global environment and the work environment.
In addition, a technology is under investigation in which a polymerizable compound and a polymerization initiator are contained in an ink, and this ink is cured whereby to form an image having high scratch resistance to scratch and the like (hereinafter, also referred to as the “scratch resistance”).
For example, known is an ink used for inkjet recording containing a coloring material, a polymerizable oligomer, a photopolymerization initiator and water, in which the photopolymerization initiator has 3% by weight or more of the solubility with respect to water, as an ink that has less influence of the photo-curable oligomer and the photopolymerization initiator, which are essential components of a photo-curable ink, on the image (for example, see Japanese Patent Application Laid-Open (JP-A) No. 2000-186242).
In addition, known is an ink for inkjet that is excellent in preservation stability and discharge stability of the ink, has diversity for a recording medium, and allows an image excellent in bleed resistance, scratch resistance, water resistance and shiny appearance, which contains a coloring material, water, a high molecular compound which has plural side chains in a hydrophilic main chain and can be crosslinked between the side chains by irradiation of an active energy ray, and a water-soluble photopolymerization initiator (for example, see JP-A No. 2012-137964).
In addition, known is an ink set that can form an image by being immobilized onto a recording medium, and is excellent in the scratch resistance, and excellent in evenness of the surface of an image and blocking resistance, which contains an ink composition including a pigment, polymer particles having a glass transition temperature of 70° C. or higher and a volume average particle diameter of 70 nm or less, and a water-soluble polymerizable compound being polymerized by an active energy ray, and a process liquid containing a flocculant that flocculates the components in the ink composition (for example, see JP-A No. 2011-46872).
In addition, known is an ink composition that is excellent in preservation stability and curability after image formation, which contains a specific structure of a polyvalent (meth)acrylamide compound and a polymerization initiator (for example, see JP-A No. 2013-18846).