Method for manufacturing toner

Abstract

A kneaded material obtained by heating and melt-kneading a toner composition and a water-based medium containing water are put into a container of a granulating apparatus, and heated by a heater while agitating, to disperse the kneaded material into the water-based medium in its softened state. A temperature at which a loss tangent value of the kneaded material reaches a predetermined loss tangent value A, specifically, 0.5 or more and less than 5.0, is inputted to a granulating temperature input section as a setting granulating temperature T1. The heater is then controlled by a control section so that a granulating temperature as a temperature of the water-based medium measured by a thermometer reaches the setting granulating temperature T1 inputted to the input section. Accordingly, the granulating temperature as a temperature of the water-based medium, and thus a temperature of the kneaded material in the water-based medium is adjusted to T1.

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 procedure of a method for manufacturing a toner according to one embodiment of the invention;

FIG. 2 is a partially sectional view schematically showing a configuration of a granulating apparatus as one example of the granulating apparatus used for the method for manufacturing a toner according to the embodiment;

FIG. 3 is the partially sectional view, on an enlarged scale, showing an internal configuration of a screen of FIG. 2; and

FIG. 4 is a view schematically showing a loss tangent-temperature characteristic curve.

Claims

1. A method for manufacturing a toner comprising: a kneading step for heating and melt-kneading a toner composition containing at least a binder resin and a colorant to produce a kneaded material in which at least the colorant is dispersed in the binder resin; anda granulating step for mixing the kneaded material with a water-based medium, and then a mixture obtained is heated to disperse the kneaded material into the water-based medium in a state in which the kneaded material is softened,wherein a granulating temperature at the granulating step is a temperature at which a loss tangent obtained by dividing a loss elastic modulus G″ of the kneaded material by a storage elastic modulus G′ reaches a predetermined loss tangent value A.

2. The method of claim 1, wherein the loss tangent of the kneaded material is measured at a setting frequency of 0.1 Hz, and the predetermined loss tangent value is 0.5 or more and less than 5.0.

3. The method of claim 1, wherein the granulating temperature at the granulating step is adjusted to a temperature at which the loss elastic modulus G″ of the kneaded material reaches a range of from 103 Pa to 105 Pa at a setting frequency of 0.1 Hz.

4. The method of claim 1, wherein the toner composition further comprises a release agent, wherein the granulating temperature at the granulating step is lower than a melting point of the release agent.