| US 7,537,654 B1 | ||
| Quinacridone nanoscale pigment particles and methods of making same | ||
| Roger E. Gaynor, Oakville (Canada); and C. Geoffrey Allen, Waterdown (Canada) | ||
| Assigned to Xerox Corporation, Norwalk, Conn. (US) | ||
| Filed on Sep. 15, 2008, as Appl. No. 12/210,613. | ||
| Int. Cl. C09B 48/00 (2006.01); B05D 7/00 (2006.01) | ||
| U.S. Cl. 106—497 [106/495; 427/212; 546/49; 546/56] | 22 Claims |
| 1. A process for preparing coated nanoscale quinacridone pigment particles, comprising:
mixing a quinacridone pigment precursor or crude quinacridone pigment with a first solution comprising an acid to form nanoscale
quinacridone pigment particles;
adding the first solution and formed nanoscale quinacridone pigment particles into a second solution comprising deionized
water to form a third solution and to precipitate the nanoscale quinacridone pigment particles; and
washing the precipitated nanoscale quinacridone pigment particles in a fourth solution comprising a surface additive compound,
whereby said surface additive compound coats the nanoscale quinacridone pigment particles;
wherein the surface additive compound comprises a rosin compound.
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