Electrostatic latent image developing toner, and method for manufacturing electrostatic latent image developer and electrostatic latent image developing toner

1. An electrostatic latent image developing toner including a binder resin, a colorant, and a release agent, wherein:

shape factor SF1 of the toner is within a range from 110 to 140, where SF1=(ML 2 /A)·(π/4)·100, ML denoting an absolute maximum length of a toner particle and A denoting a projected area of a toner particle;

volume average particle size of the toner is within a range from 1.2 pm to 4.8 μm;

crystallinity of the release agent within the toner is within a range from 35 to 80; and

R/D is within a range from 0.2 to 0.6, where R denotes a domain average longitudinal diameter of the release agent within the toner and D denotes the volume average particle size of the toner.

2. An electrostatic latent image developing toner as defined in claim 1 , wherein the crystallinity is within a range from 40 to 75.

3. An electrostatic latent image developing toner as defined in claim 1 , wherein the crystallinity is within a range from 50 to 70.

4. An electrostatic latent image developing toner as defined in claim 1 , wherein particle size distribution GSD of the toner is no greater than 1.26, where GSD=[(d16/d84)] 0.5 , volume d16 denotes a particle size where an accumulated volume in an accumulation distribution from larger size reaches 16% and volume d84 denotes a particle size where the accumulated volume in the accumulation distribution from larger size reaches 84%.

5. An electrostatic latent image developing toner as defined in claim 1 , wherein glass transition temperature of the binder resin is within a range from 40° C. to 70° C.

6. An electrostatic latent image developing toner as defined in claim 1 , wherein weight average molecular weight Mw of the binder resin is within a range from 6000 to 45000.

7. An electrostatic latent image developing toner as defined in claim 1 , wherein the binder resin is a vinyl-based resin.

8. An electrostatic latent image developing toner as defined in claim 1 , wherein content of the release agent within the toner is within a range of 6 to 25 wt % of the toner weight.

9. An electrostatic latent image developing toner as defined in claim 1 , wherein the shape factor SF1 of the toner is within a range from 115 to 135.

10. An electrostatic latent image developing toner as defined in claim 1 , wherein the shape factor SF1 of the toner is within a range from 115 to 130.

11. An electrostatic latent image developing toner as defined in claim 1 , wherein the volume average particle size of the toner is within a range from 2.0 μm to 4.5 μm.

12. An electrostatic latent image developing toner as defined in claim 1 , wherein the volume average particle size of the toner is within a range from 2.5 μm to 4.0 μm.

13. An electrostatic latent image developer comprising an electrostatic latent image developing toner including a binder resin, a colorant, and a release agent, wherein: shape factor SF1 of the toner is within a range from 110 to 140, where SF1=(ML 2 /A)·(π/4)·100, ML denoting an absolute maximum length of a toner particle and A denoting a projected area of a toner particle;

volume average particle size of the toner is within a range from 1.2 μm to 4.8 μm;

crystallinity of the release agent within the toner is within a range from 35 to 80; and

R/D is within a range from 0.2 to 0.6, where R denotes a domain average longitudinal diameter of the release agent within the toner and D denotes the volume average particle size of the toner.

14. A method for manufacturing an electrostatic latent image developing toner including a binder resin, a colorant, and a release agent, the method comprising a process of granulating particles of the toner, the granulating process including:

a step of heating to or above glass transition temperature of the binder resin; and

a step of cooling performed after the heating step by speedily cooling at a cooling rate of 10°C./minute or faster from the temperature of the heating step, wherein:

the toner obtained as a result of the granulating process is such that:

shape factor SF1 of the toner is within a range from 110 to 140, where SF1=(ML 2 /A)·(π/4)·100, ML denoting an absolute maximum length of a toner particle and A denoting a projected area of a toner particle;

volume average particle size of the toner is within a range from 1.2 μm to 4.8 μm;

crystallinity of the release agent within the toner is within a range from 35 to 80; and

R/D is within a range from 0.2 to 0.6, where R denotes a domain average longitudinal diameter of the release agent within the toner and D denotes the volume average particle size of the toner.

15. A method for manufacturing an electrostatic latent image developing toner as defined in claim 14 , wherein the cooling step includes adding, into a tank in which the granulating process is performed, a cooled solvent or a solid obtained by cooling and solidifying the solvent.

16. A method for manufacturing an electrostatic latent image developing toner as defined in claim 14 , wherein the cooling step includes adding, into a tank in which the granulating process is performed, a liquid or solid form of a cooling substance that is in gas phase at room temperatures.

17. A method for manufacturing an electrostatic latent image developing toner as defined in claim 14 , wherein

the heating step includes heating to or above a temperature value that is 1.6 times greater than the glass transition temperature of the binder resin, and

the cooling step includes cooling, after the heating step, to a temperature below a value that is 1.4 times greater than the glass transition temperature of the binder resin.

18. A method for manufacturing an electrostatic latent image developing toner as defined in claim 17 , wherein the cooling step includes adding, into a tank in which the granulating process is performed, a cooled solvent or a solid obtained by cooling and solidifying the solvent.

19. A method for manufacturing an electrostatic latent image developing toner as defined in claim 17 , wherein the cooling step includes adding, into a tank in which the granulating process is performed, a liquid or solid form of a cooling substance that is in gas phase at room temperatures.