| 摘要 |
PURPOSE:To enhance electrifiability to negative charges, developability, and transferability by incorporating a polymer having acid anhydride groups or acid groups obtained by partially esterifying them as polar groups, and an acid value of >=100. CONSTITUTION:The polymer having acid anhydride groups or acid groups obtained by partially esterifying them, as polar groups, and an acid value of >=100 is used for the developer composition composed essentially of a colorant and a binder resin, and as said polymer having the acid anhydride groups, polymers having, as the units of monomers, such as acrylic anhydride, methacrylic anhydride, and the anhydride of acrylic acid and propionic acid, are enumerated. The addition of some amount of said high-acid-value polymer permits the obtained developer composition to exhibit extremely rapid rising of electrification, stability against circumstantial conditions, and narrow electrification quantity distribution, consequently, to be improved in developability and transferability, and always good image quality to be ensured. |
