Toner processes using in-situ tricalcium phospate

• US 5,925,488 A
• Filed: 11/18/1997
• Issued: 07/20/1999
• Est. Priority Date: 09/03/1996
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Kmieckik-Lawrynowicz, Grazyna E., Patel, Raj D., Paine, Anthony J., Ng, T. Hwee
• Primary Examiner(s): Rodee, Christopher D.
• Application Number:
  US08/972,380
• Time in Patent Office: 609 Days
• Field of Search: 430/137, 430/111
• US Class Current: 430/137.14
• CPC Class Codes: G03G 9/0804 whereby the components are brought together in a liquid dispersing medium
• CPC Class Codes: Y10S 977/788 Of specified organic or carbon-based composition

Abstract

A process for the preparation of toner which comprises

(i) preparing a pigment dispersion comprised of a pigment dispersed in an ionic surfactant;

(ii) shearing said pigment dispersion with a latex or emulsion blend comprised of resin particles and a counterionic surfactant;

(iii) heating the above sheared blend below the glass transition temperature (Tg) of said resin particles to form electrostatically bound toner size aggregates;

(iv) adding a stabilizer of in situ tricalcium phosphate solid particulants generated from a solution of calcium chloride and trisodium phosphate;

(v) heating the mixture of (iii) and (iv) above about the Tg of the resin particles to obtain toner size particles comprised of resin and pigment;

(vi) washing with an acid to dissolve the trisodium phosphate; and

(vii) optionally washing with water, and optionally drying the toner obtained.

Claims

1. A process for the preparation of toner which consists essentially of mixing a colorant dispersion and a latex, wherein said colorant dispersion is comprised of colorant and ionic surfactant, and said latex is comprised of resin and counterionic surfactant;

heating below the resin Tg temperature;

adding in situ tricalcium phosphate;

heating above the resin Tg, followed by optionally washing with water, and optionally drying said toner.

2. A process in accordance with claim 1 wherein the amount of tricalcium phosphate (TCP) selected is about 0.1 to about 5.0 weight percent based on the weight percent of all components selected.

3. A process in accordance with claim 1 wherein the in situ tricalcium phosphate is in the form of solid particles having a size of from about 0.2 to 0.8 micron volume average diameter.

4. A process in accordance with claim 1 wherein the resin is selected from the group consisting of poly(styrene-butadiene), poly(para-methyl styrene-butadiene), poly(meta-methylstyrene-butadiene), poly(alpha-methylstyrene-butadiene), poly(methylmethacrylate-butadiene), poly(ethylmethacrylate-butadiene), poly(propylmethacrylate-butadiene), poly(butylmethacrylate-butadiene), poly(methylacrylate-butadiene), poly(ethylacrylate-butadiene), poly(propylacrylate-butadiene), poly(butylacrylate-butadiene), poly(styrene-isoprene), poly(para-methyl styrene-isoprene), poly(meta-methylstyrene-isoprene), poly(alpha-methylstyrene-isoprene), poly(methylmethacrylate-isoprene), poly(ethylmethacrylate-isoprene), poly(propylmethacrylate-isoprene), poly(butylmethacrylate-isoprene), poly(methylacrylate-isoprene), poly(ethylacrylate-isoprene), poly(propylacrylate-isoprene), and poly(butylacrylate-isoprene).

5. A process in accordance with claim 1 wherein there results said toner composition with a volume average diameter of from about 1 to about 10 microns.

6. A process in accordance with claim 1 wherein said in situ tricalcium phosphate is in a solid form and is present in an amount of 0.8 to 2.3 percent by weight.

7. A process in accordance with claim 6 wherein said colorant is a pigment.