Patent ID: 7427130

Claim:
A process for forming an image, comprising: applying a recording composition comprising a colorant and a treating composition comprising a component reactive with the colorant as droplets so that the compositions contact and mix with each other on a recording medium; and adjusting the pH of the mixture so that the treating composition and the recording composition react to form aggregates while any unreacted component that would react with the colorant forms aggregates as a simple substance, wherein the component that reacts with the colorant has an isoelectric point at which the zeta potential (ζ) is 0 when the zeta potential (ζ) change of the component is plotted relative to corresponding changes in the pH of the mixture, and the recording composition and treating composition are respectively adjusted to satisfy a<γ and a<c, wherein “c” is a pH value of the isoelectric point, “a” is a pH value of the mixture where the zeta potential (ζ) change according to pH is on the more acidic side than the pH (c) of the isoelectric point, and is about −2.5 mV·l/mol, and “γ” is the pH of the mixture.