Yellow toner, developing agent, toner cartridge, process cartridge, image forming apparatus and image forming process
View Patent ↗The invention provides a yellow toner including toner particles comprising colorants and a binder resin, the colorants including at least a C. I. Pigment yellow 180 and a carmine-based pigment, a weight ratio of the C. I. Pigment yellow 180 to the carmine-based pigment being from about 99:1 to about 10,000:1, the binder resin being a polyester resin comprising a first repeating unit derived from a first diol compound, and the first diol compound being a bisphenol A ethylene oxide represented by the following formula (1): wherein in formula (1), m and n each independently represent an integer of from 2 to 4.
1. A yellow toner comprising toner particles comprising colorants and a binder resin, the colorants comprising at least a C. I. Pigment yellow 180 and a carmine-based pigment, a weight ratio of the C. I. Pigment yellow 180 to the carmine-based pigment being from about 99:1 to about 2,500:1, the binder resin being a polyester resin comprising a first repeating unit derived from a first diol compound, and the first diol compound being a bisphenol A ethylene oxide represented by the following formula (1):
wherein in formula (1), m and n each independently represent an integer of from 2 to 4.
2. The yellow toner of claim 1 , wherein a volume average particle diameter of the yellow toner is from about 8 μm to about 15 μm.
3. The yellow toner of claim 1 , wherein a shape factor SF1 of the yellow toner is from about 140 to about 160.
4. The yellow toner of claim 1 , wherein the toner particles further comprise a hydrocarbon-based wax as a release agent.
5. The yellow toner of claim 4 , wherein the hydrocarbon-based wax is a paraffin-based wax.
6. The yellow toner of claim 1 , wherein a glass transition temperature of the yellow toner is from about 35° C. to about 50° C.
7. The yellow toner of claim 1 , wherein a total amount of the colorants included in the toner particles is from about 1 part by weight to about 20 parts by weight with respect to 100 parts by weight of the binder resin.
8. The yellow toner of claim 1 , wherein the polyester resin further comprises a second repeating unit derived from a second diol compound, and a ratio of the first repeating unit derived from the first diol compound to a total of repeating units derived from diol, including the first repeating unit and the second repeating unit, is about 80 mol % or more.
9. The yellow toner of claim 1 , wherein a glass transition temperature of the polyester resin is from about 45 0° C. to about 50° C.
10. The yellow toner of claim 1 , wherein a weight average molecular weight of the polyester resin is from about 5,000 to about 30,000.
11. The yellow toner of claim 1 , wherein a total amount of the binder resin included in the toner particles is from about 40% by weight to about 95% by weight with respect to a total weight of solid contents in the toner particles.
12. The yellow toner of claim 1 , wherein the carmine-based pigment is a C. I. Pigment Red 57:1.
13. The yellow toner of claim 1 , wherein the toner particles are obtained by kneading a toner forming material comprising the colorants and the binder resin to give a kneaded product, and pulverizing the kneaded product.
14. A developing agent comprising the yellow toner of claim 1 .
15. A toner cartridge in which the yellow toner of claim 1 is housed, the toner cartridge being attachable to and detachable from an image forming apparatus.
16. A process cartridge comprising a developing unit that houses the developing agent of claim 14 , develops an electrostatic latent image formed on a surface of a latent image holding member by way of the developing agent so as to form a toner image, and is attachable to and detachable from an image forming apparatus.
17. An image forming apparatus comprising:
a latent image holding member,
a charging unit that charges a surface of the latent image holding member,
an electrostatic latent image forming unit that forms an electrostatic latent image on the surface of the latent image holding member,
a developing unit that develops the electrostatic latent image with the developing agent of claim 14 to form a toner image,
a transfer unit that transfers the toner image onto a recording medium, and
a fixing unit that fixes the toner image on the recording medium.
18. A process for forming an image, comprising:
developing an electrostatic latent image with a plurality of toners to form a plurality of toner images with the plurality of toners,
transferring the plurality of toner images onto a surface of a recording medium to form a superposed toner image comprising a plurality of layers, and
fixing the superposed toner image to form an image,
the plurality of toners comprising at least the yellow toner of claim 1 and a magenta toner comprising a carmine-based pigment as a colorant.
19. The yellow toner of claim 1 , wherein the weight ratio of the C. I. Pigment yellow 180 to the carmine-based pigment is from about 1,000:1 to about 2,500:1.