Ink set for use in ink-jet recording, image forming process and image recording apparatus

An image forming process comprising the steps of:

• providing an ink set comprising at least 2 ink compositions having solid content concentrations which are different by more than 2% by mass,
• wherein said at least 2 ink compositions each comprise an aqueous medium, a pigment and a dispersant for dispersing the pigment, and the dispersant is an amphiphilic block copolymer having an A segment that is a hydrophobic segment, a B segment that is a nonionic hydrophilic segment, and a C segment that is an ionic hydrophilic segment, and
• wherein the number of unit structures of the B segment of the amphiphilic block copolymer contained in each of said at least 2 ink compositions is smaller in the amphiphilic block copolymer contained in the ink composition having a relatively high solid content concentration than in the amphiphilic block copolymer contained in the ink composition having a relatively low solid content concentration;
• and
• applying energy to the ink compositions of the ink set to eject the ink compositions on a recording medium to thereby form an image.

An image recording apparatus comprising:

• an ink set:
• and
• a device for applying energy to ink compositions of the ink set to eject the ink compositions on a recording medium to thereby form an image,
• wherein the ink set comprises at least 2 ink compositions having solid content concentrations which are different by more than 2% by mass,
• wherein said at least 2 ink compositions each comprise an aqueous medium, a pigment and a dispersant for dispersing the pigment, and the dispersant is an amphiphilic block copolymer having an A segment that is a hydrophobic segment, a B segment that is a nonionic hydrophilic segment, and a C segment that is an ionic hydrophilic segment, and
• wherein the number of unit structures of the B segment of the amphiphilic block copolymer contained in each of said at least 2 ink compositions is smaller in the amphiphilic block copolymer contained in the ink composition having a relatively high solid content concentration than in the amphiphilic block copolymer contained in the ink composition having a relatively low solid content concentration.