Method of manufacturing toner and toner

Abstract

A toner is manufactured by way of a coarse particle preparing step, a slurry preparing step, a pulverizing step, a cooling step, and a depressurizing step. Slurry of toner coarse particles obtained by way of the coarse particle preparing step and the slurry preparing step is made to pass under heat and pressure through a pressure-resistant nozzle whereby toner coarse particles are pulverized into diameter-reduced toner particles. By providing the cooling step immediately after the pulverizing step, dispersion of wax component into the toner particles is promoted. And by further providing the depressurizing step, bubbling and coarsening of the toner particles due to the bubbling are prevented. By so doing, there is obtained a diameter-reduced toner particle in which wax is evenly dispersed and which does not cause bleeding out.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other and further objects, features, and advantages of the invention will be more explicit from the following detailed description taken with reference to the drawings wherein:

FIG. 1 is a flowchart showing a method of manufacturing a toner according to a first embodiment of the invention; and

FIG. 2 is a sectional view schematically showing a configuration of a pressure-resistant nozzle.

Claims

1. A method of manufacturing a toner comprising: a coarse particle preparing step for coarsely pulverizing a melt-kneaded product of toner raw material;a slurry preparing step for obtaining coarse particle slurry by adding and dispersing coarse particles of toner raw material obtained at the coarse particle preparing step, in a liquid;a pulverizing step for obtaining heated and pressurized slurry containing toner particles by passing the coarse particle slurry obtained at the slurry preparing step through a pressure-resistant nozzle under heat and pressure and pulverizing the coarse particles of toner raw material;a cooling step for cooling down the heated and pressurized slurry containing toner particles, obtained at the pulverizing step; anda depressurizing step for gradually depressurizing the pressurized slurry containing toner particles, cooled down at the cooling step, to a pressure level at which no bubbling is caused.

2. The method of claim 1, wherein the liquid in which coarse particles of toner raw material are added and dispersed at the slurry preparing step is water.

3. The method of claim 1, wherein the liquid in which the coarse particles of toner raw material are added and dispersed at the slurry preparing step is water containing a polymeric dispersant.

4. The method of claim 1, wherein the slurry obtained at the slurry preparing step is pressurized at a pressure in a range from 50 MPa to 250 MPa, and heated to 50° C. or more at the pulverizing step.

5. The method of claim 1, wherein the slurry obtained at the slurry preparing step is pressurized at a pressure in a range from 50 MPa to 250 MPa, and heated to 90° C. or more at the pulverizing step.

6. The method of claim 1, wherein the pressure-resistant nozzle is a multiple nozzle.

7. The method of claim 1, wherein the pressure-resistant nozzle is a nozzle having a liquid flowing passage therein provided with at least a collision wall against which a liquid flowing through the liquid flowing passage collides.

8. The method of claim 1, wherein at the depressurizing step, a pressure on the slurry is gradually reduced to a level at which no bubbling is caused by passing the pressurized slurry containing toner particles, which is cooled down at the cooling step, through a multistage depressurization apparatus for performing stepwise depressurization.

9. The method of claim 1, wherein the multistage depressurization apparatus used at the depressurizing step comprises: an inlet passage for leading the pressurized slurry containing toner particles into the depressurization apparatus;an outlet passage in communication with the inlet passage, for discharging the slurry containing toner particles to outside of the depressurization apparatus; anda multistage depressurization section disposed between the inlet passage and the outlet passage, on which two or more depressurization members are coupled via coupling members, for performing stepwise depressurization.

10. A toner manufactured by the method of manufacturing a toner according to claim 1.