Method of producing polymerized toner

Abstract

The present invention provides a method of producing a polymerized toner which is capable of dispersing a colorant in a polymerizable monomer finely and uniformly and is excellent in production efficiency, wherein a step of preparing a polymerizable monomer composition containing the polymerizable monomer and the colorant includes a dispersing process in which a polymerizable monomer mixture containing the polymerizable monomer and the colorant is supplied to a media type dispersing machine equipped with a media particle and a screen for media separation and the colorant is dispersed in the polymerizable monomer mixture to obtain a polymerizable monomer dispersion, wherein a media diameter of the media particle and an aperture ratio of the screen for media separation satisfy the following formulas 1 and 2:

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings,

FIG. 1 is an explanatory diagram showing a preliminary dispersion system employed in examples of the present invention;

FIG. 2 is an explanatory diagram showing a dispersion system employed in examples of the present invention;

FIG. 3 is a sectional view showing an example of a media type dispersing machine equipped with a screen for media separation used in the present invention;

FIG. 4 is an explanatory diagram showing a rotor used in a media type dispersing machine equipped with a screen for media separation used in the present invention;

FIG. 5 is a sectional view showing an example of a conventional media type dispersing machine;

FIG. 6 is a side view of one constitutional example of a notch wire type screen (partially omitted); and

FIG. 7 is a partially enlarged view of an element surface shown in FIG. 6.

Claims

1. A method of producing a polymerized toner comprising the steps of: (1) preparing a polymerizable monomer composition containing a polymerizable monomer and a colorant;(2) forming a droplet of the polymerizable monomer composition by dispersing the polymerizable monomer composition in an aqueous dispersion medium; and(3) forming a colored resin particle by polymerizing the droplet of the polymerizable monomer composition,wherein the step (1) includes a dispersing process in which a polymerizable monomer mixture containing the polymerizable monomer and the colorant is supplied to a media type dispersing machine equipped with a media particle and a screen for media separation and the colorant is dispersed in the polymerizable monomer mixture to obtain a polymerizable monomer dispersion, andwherein a media diameter of the media particle and an aperture ratio of the screen for media separation satisfy the following formulas 1 and 2:

2. A method of producing a polymerized toner according to claim 1, wherein the polymerizable monomer mixture is subject to preliminary dispersion and an obtained preliminarily-dispersed polymerizable monomer mixture is supplied to the media type dispersing machine in the step (1).

3. A method of producing a polymerized toner according to claim 2, wherein the polymerizable monomer mixture contains a colorant having a volume average particle diameter of 20 μm or more and/or a colorant which has a volume percentage (D51) of a particle having a particle diameter of 51 μm or more by 20% or more.

4. A method of producing a polymerized toner according to claim 2, wherein after the polymerizable monomer mixture comprising the polymerizable monomer and the colorant is subject to preliminary dispersion and an obtained preliminarily-dispersed polymerizable monomer mixture is supplied to the media type dispersing machine for dispersion, other components required for the toner are added to the obtained polymerizable monomer dispersion in the step (1).

5. A method of producing a polymerized toner according to claim 2, wherein a method of the preliminary dispersion is a method using a preliminary dispersing machine beside the method using the media type dispersing machine equipped with the screen for media separation.

6. A method of producing a polymerized toner according to claim 5, wherein the preliminary dispersion is performed by applying mechanical shearing stress to the colorant in the polymerizable monomer mixture.

7. A method of producing a polymerized toner according to claim 5, wherein a peripheral speed at the edge of a stirring vane of the preliminary dispersing machine is from 15 to 60 m/s.

8. A method of producing a polymerized toner according to claim 5, wherein an inner pressure of the preliminary dispersing machine is in the range of 0.01 to 15 MPa.

9. A method of producing a polymerized toner according to claim 2, wherein the preliminary dispersion is performed while holding a temperature variation range of the polymerizable monomer mixture before and after the preliminary dispersion preferably at 30° C. or less.

10. A method of producing a polymerized toner according to claim 2, wherein a volume average particle diameter of the colorant of the preliminarily-dispersed polymerizable monomer mixture is less than 20 μm and a volume percentage (D51) of a particle having a particle diameter of 51 μm or more of the colorant of the preliminarily-dispersed polymerizable monomer mixture is less than 20%.

11. A method of producing a polymerized toner according to claim 1, wherein the polymerizable monomer mixture or a preliminarily-dispersed polymerizable monomer mixture obtained by preliminarily dispersing the polymerizable monomer mixture is supplied to the media type dispersing machine to disperse the colorant, discharged from the media type dispersing machine, supplied again to the media type dispersing machine, and continuously circulated at a circulation number of two or more in the process of dispersion in the process of dispersion.

12. A method of producing a polymerized toner according to claim 1, wherein a ratio of a volume of the media particle with respect to an inner volume of the media type dispersing machine where the media particle is present is from 60 to 95 volume percent.

13. A method of producing a polymerized toner according to claim 1, wherein a viscosity of a polymerizable monomer dispersion to be obtained by the process of dispersion is from 300 to 2,500 cP.

14. A method of producing a polymerized toner according to claim 1, wherein a colorant dispersing agent is added to the polymerizable monomer mixture in the step (1).

15. A method of producing a polymerized toner according to claim 14, wherein the colorant dispersing agent is selected from the group consisting of an Al coupling agent, a silane coupling agent and a titanate coupling agent.

16. A method of producing a polymerized toner according to claim 14, wherein the polymerizable monomer mixture with the colorant dispersing agent added is subject to preliminary dispersion and an obtained preliminarily-dispersed polymerizable monomer mixture is supplied to the media type dispersing machine in the step (1).

17. A method of producing a polymerized toner according to claim 1, wherein the liquid temperature of the polymerizable monomer mixture or the polymerizable monomer dispersion is in the range of 10 to 30° C. in the step (1).

18. A method of producing a polymerized toner according to claim 1, wherein a media diameter of the media particle is 0.01 mm or more and 0.1 mm or less in the dispersion process.

19. A method of producing a polymerized toner according to claim 1, wherein the screen for media separation is a notch wire type or a wedge wire type cylindrical screen.

20. A method of producing a polymerized toner according to claim 1, wherein a rotor and a casing of the media type dispersing machine, which contacts with the polymerizable monomer mixture or the polymerizable monomer dispersion, is made of a material having Rockwell Hardness C-Scale (HRC) of 20 or more.