Photo Imaging with Ink Jet Inks

Abstract

Both dye-based and pigment-based aqueous ink jet inks are capable of providing excellent photo quality in the current generation of low drop volume high resolution small office home office (SOHO) ink jet printers, especially when printed on special coated glossy ink jet photo papers. However, no one system delivers the perfect balance of color, image quality, physical durability, glossy uniformity, and image permanence.The primary factors causing color fade and loss of image permanence in dye-based ink jet inks are environmental conditions such as light, heat, air quality, and humidity. Dye inks printed on microporous photo media undergo color fade much more rapidly than on polymeric nonporous coated photo media, with a significant color changed observed sometimes in a matter of weeks.When image permanence is required for photo printing, pigment-based ink jet inks are the choice. One of the remaining image quality issues with pigment inks is nonuniform gloss. For photographic and other high definition imaging, uniform high gloss is desirable to enhance the perception of clarity and sharpness of the image. When a significant difference in gloss occurs between inked and unprinted areas (media), the image appears to have “flat”, non-shiny areas in the photo print. In our studies of gloss uniformity, we found nonuniform gloss also can occur with dye-based ink jet inks printed on glossy media.This paper will summarize our studies of gloss as function of ink formulation parameters: colorant (pigment or dye), dispersant type/dispersion process (pigment), vehicle (co-solvents, surfactants) and water. This gloss study included a variety of glossy media types. Additionally, the color gamut of current pigment inks printed on glossy photo papers will be reviewed.