Method of manufacturing toner and toner manufactured by the method
A method of manufacturing toner including melting, mixing, and kneading a releasing agent and a coloring agent with at least part of a polyester binder resin, and suspending and granulating an oil phase comprising the binder resin, the coloring agent, and the releasing agent in an aqueous medium.
1. A method of manufacturing toner, comprising:
melting, mixing, and kneading a releasing agent and a coloring agent with at least part of a polyester binder resin to form a toner material where the releasing agent is dispersed in at least part of said polyester binder resin;
pulverizing the toner material to form a powder comprised of said releasing agent, said coloring agent, and at least part of said polyester binder resin;
dissolving said powder in an oil phase; and
suspending said oil phase comprising said powder, dissolved in the oil, in an aqueous medium to obtain a toner that does not exhibit cold offset at a temperature of 140° C. or higher, wherein
the polyester binder resin comprises a polyol component that comprises at least 50 mol % of an adduct of propylene oxide and a bisphenol, based on the diol component of the polyester resin,
a melting point of the releasing agent is from 70 to 110° C., and
a content of said polyester binder resin having a weight average molecular weight of less than 1,000 is from 8 to 28% by weight of said polyester binder resin.
2. The method of manufacturing toner according to claim 1 , wherein the releasing agent is a hydrocarbon-based wax modified by a carboxylic acid or an anhydride of a carboxylic acid.
3. The method of manufacturing toner according to claim 1 , wherein a melting point of the releasing agent is lower than a melting point of the binder resin.
4. The method of manufacturing toner according to claim 1 , wherein an acid value of the releasing agent ranges from 3 to 20 mgKOH/g.
5. The method of manufacturing toner according to claim 1 , wherein an acid value of the polyester resin ranges from 5 to 40 mgKOH/g.
6. The method of manufacturing toner according to claim 1 , wherein the releasing agent has a viscosity of from 5 to 50 cm poise at 90° C.
7. The method of manufacturing toner according to claim 1 , wherein the coloring agent comprises a press cake pigment formed by washing and filtering the pigment.
8. The method of manufacturing toner according to claim 1 , wherein the melting, mixing, kneading of the binder resin, the releasing agent, and the coloring agent is conducted using an open-type melting, mixing and kneading machine.
9. The method of manufacturing toner according to claim 1 , wherein said melting, mixing, and kneading is a preliminary melting, mixing, and kneading where each of the melting, mixing, and kneading are carried out prior to said suspending and granulating.
10. A method of manufacturing toner, comprising:
melting, mixing, and kneading a releasing agent and a coloring agent with at least part of a polyester binder resin; and
suspending and granulating an oil phase comprising the binder resin, the coloring agent, and the releasing agent in an aqueous medium to obtain a toner,
wherein
a melting point of the releasing agent ranges from 70 to 110° C.,
a melting point of the polyester binder resin ranges from 103 to 120° C.,
an acid value of the releasing agent ranges from 1.2 to 23 mgKOH/g,
an acid value of the polyester resin ranges from 5 to 40 mgKOH/g, and
provided at least one of the following:
the melting point of the releasing agent is lower than the melting point of the binder resin, and
the acid value of the releasing agent is lower than the acid value of the binder resin.
11. The method of manufacturing toner according to claim 9 , wherein
a melting point of the releasing agent ranges from 76 to 108° C.,
a melting point of the polyester binder resin ranges from 103 to 120° C.,
an acid value of the releasing agent ranges from 1.2 to 23 mgKOH/g, and
an acid value of the polyester resin ranges from 4.7 to 16.1 mgKOH/g.