Radiation-curable ink compositions and methods of printing including
the compositions are disclosed. In some embodiments, a radiation-curable hot melt
ink composition includes a colorant, a polymerizable monomer, and a photoinitiating
system. The photoinitiating system can include 0.5-1.5% by weight of an aromatic
ketone photoinitiator, 2-10% by weight of an amine synergist, 3-8% by weight of
an alpha-cleavage type photoinitiator, and 0.5-1.5% by weight of a photosensitizer.
