Method for manufacturing toner for developing electrostatic latent image

• US 5,928,831 A
• Filed: 12/22/1998
• Issued: 07/27/1999
• Est. Priority Date: 12/26/1997
• Status: Expired due to Term

• Current Assignee: Minolta Co., Ltd. (Konica Minolta Inc.)
• Original Assignee: Minolta Co., Ltd. (Konica Minolta Inc.)
• Inventors: Nakamura, Mitsutoshi
• Primary Examiner(s): MARTIN, ROLAND E
• Application Number:
  US09/217,583
• Time in Patent Office: 217 Days
• Field of Search: 430/137
• US Class Current: 430/137.14
• CPC Class Codes: G03G 9/0804 whereby the components are brought together in a liquid dispersing medium

Abstract

A present invention relates to a method for producing a toner for developing electrostatic latent images comprising the steps of preparing a coloring resin solution containing a binder resin, a colorant and a non-aqueous organic solvent, forming an oil-in-water type emulsion by adding the coloring resin solution to an aqueous medium under reduced pressure of 5.0×10⁴ to 1.0×10^-2 Pa and removing the non-aqueous organic solvent from the oil-in-water type emulsion.

Claims

1. A method of producing a toner for developing electrostatic latent images comprising the steps of:

preparing a coloring resin solution containing a binder resin, a colorant and a non-aqueous organic solvent;

forming an oil-in-water type emulsion by adding the coloring resin solution to an aqueous medium under reduced pressure of 5.0×

10⁴ to 1.0×

10^-2 Pa; and

removing the non-aqueous organic solvent from the oil-in-water type emulsion.

2. The method as claimed in claim 1, wherein the reduced pressure is 3.0×

10⁴ to 1.0×

10^-1 Pa.

3. The method as claimed in claim 1, wherein the reduced pressure is 1.4×

10⁴ to 1.0 Pa.

4. The method as claimed in claim 1, wherein the coloring resin solution has a resin concentration of 5 to 50% by weight.

5. The method as claimed in claim 1, wherein an amount of cavities in the toner is less than 5%.

6. The method as claimed in claim 1, wherein the toner has a coefficient of variation of less than 35%.

7. The method as claimed in claim 1, wherein the toner has a volume-average particle size of 3 to 9 μ

m.

8. The method as claimed in claim 1, wherein the binder resin has a glass transition temperature of 50 to 70°

C., a number-average molecular weight of 1,000 to 50,000, and a ratio (a weight-average molecular weight/a number-average molecular weight) of 2 to 60.

9. The method as claimed in claim 8, wherein the binder resin has the ratio of 2 to 5.

10. The method as claimed in claim 8, wherein the binder resin has the ratio of 20 to 50.

11. A method of producing a toner for developing electrostatic latent images comprising the steps of:

preparing a coloring resin solution containing a binder resin, a colorant and a non-aqueous organic solvent;

forming an oil-in-water type emulsion by adding an aqueous medium to the coloring resin solution under reduced pressure of 5.0×

10⁴ to 1.0×

10^-2 Pa and making a phase inversion emulsification; and

removing the non-aqueous organic solvent from the oil-in-water type emulsion.

12. The method as claimed in claim 11, wherein the reduced pressure is 3.0×

10⁴ to 1.0×

10^-1 Pa.

13. The method as claimed in claim 11, wherein the reduced pressure is 1.4×

10⁴ to 1.0 Pa.

14. The method as claimed in claim 11, wherein the coloring resin solution has a resin concentration of 5 to 50% by weight.

15. The method as claimed in claim 11, wherein an amount of cavities in the toner is less than 5%.

16. The method as claimed in claim 11, wherein the toner has a coefficient of variation of less than 35%.

17. The method as claimed in claim 11, wherein the toner has a volume-average particle size of 3 to 9 μ

m.

18. The method as claimed in claim 11, wherein the binder resin has a glass transition temperature of 50 to 70°

C., a number-average molecular weight of 1,000 to 50,000, and a ratio (a weight-average molecular weight/a number-average molecular weight) of 2 to 60.

19. The method as claimed in claim 18, wherein the binder resin has the ratio of 2 to 5.

20. The method as claimed in claim 18, wherein the binder resin has the ratio of 20 to 50.