Full-color toner, image forming method, and image forming apparatus

1. A full-color toner set comprising:

a yellow component comprising a monoazo pigment;

a cyan component; and

a magenta component;

wherein each component comprises:

base particles; and

resin fine particles added to at least a portion of an external surface of the base particles,

wherein an amount of charge of the yellow component is substantially the same as that of each of the cyan and the magenta components, and

formulae (1) and (2) are satisfied, wherein the amount of the resin fine particles based on 100 parts by mass of base particles in the yellow component is represented by Wy, the amount of the resin fine particles based on 100 parts by mass of base particles in the cyan component is represented by We; and the amount of the resin fine particles based on 100 parts by mass of base particles in the magenta component is represented by Wm,

Wy>Wc   (1)

Wy>Wm   (2).

2. The full-color toner set according to claim 1 wherein the resin fine particles are copolymers comprising an acrylate monomer having an isobornyl group and a styrene monomer.

3. The full-color toner set according to claim 1 wherein a value of Wy/Wc is in a range from 1.1 to 5.0.

4. The full-color toner set according to claim 1 wherein a value of Wy/Wm is in a range from 1.1 to 5.0.

5. An image forming method comprising the steps of:

charging a image carrier by a charging unit;

forming an electrostatic image on the charged latent image carrier by an exposing unit;

developing the electrostatic latent image to a toner image with a developer from a developing unit;

and

transferring the toner image to a recording medium by a transferring portion,

wherein a toner set comprising a yellow component, a cyan component, and a magenta component is used as the developer,

wherein each component comprises resin fine particles are externally added to a surface of base particles,

wherein the yellow component comprises a monoazo pigment; and

wherein formulae (1) and (2) are satisfied, where the amount of the resin fine particles based on 100 parts by mass of base particles in the yellow component is represented by Wy, the amount of the resin fine particles based on 100 parts by mass of base particles in the cyan component is represented by Wc, and the amount of the resin fine particles based on 100 parts by mass of base particles in the magenta component is represented by Wm,

Wy>Wc   (1)

Wy>Wm   (2).

6. The image forming method according to claim 5 wherein the resin fine particles comprises acrylate monomer having an isobornyl group and a styrene monomer.

7. The image forming method according to claim 5 wherein Wy/Wc is in a range from 1.1 to 5.0.

8. The image forming method according to claim 5 wherein Wy/Wm is in a range from 1.1 to 5.0.

9. An image forming apparatus comprising:

a image carrier;

a charging unit to charge the image carrier;

an exposing unit to form an electrostatic image on the image carrier by exposing the image carrier charged by the charging unit;

a developing unit to develop the electrostatic latent image, which is formed on the image carrier by the exposing unit, with a developer so as to convert the electrostatic latent image to a toner image; and

a transferring portion to transfer the toner image on the image carrier to a recording medium,

wherein a toner set comprising a yellow component, a cyan component, and a magenta component is used as the developer;

wherein each of the yellow component, the cyan component, and the magenta component comprises base particles and resin fine particles added to the base particles;

wherein the yellow component further comprises a monoazo pigment, and

wherein an amount of charge of the yellow component is substantially the same as that of each of the cyan and the magenta components and,

formulae (1) and (2) are satisfied, where the amount of addition of the resin fine particles based on 100 parts by mass of base particles in the yellow component is represented by Wy, the amount of addition of the resin fine particles based on 100 parts by mass of base particles in the cyan component is represented by Wc, and the amount of addition of the resin fine particles based on 100 parts by mass of base particles in the magenta component is represented by Wm,

Wy>Wc   (1)

Wy>Wm   (2).

10. The image forming apparatus according to claim 9 , wherein the resin fine particles are copolymers comprising an acrylate monomer unit having an isobornyl group and a styrene monomer unit.

11. The image forming apparatus according to claim 9 wherein Wy/Wc is in a range from 1.1 to 5.0.

12. The image forming apparatus according to claim 9 wherein Wy/Wm is in a range from 1.1 to 5.0.

13. A toner set configured to inhibit image deterioration during long-term printing comprising:

a yellow component comprising:

a monoazo pigment;

base particles; and

resin fine particles configured to be added to at least a portion of an external surface of the base particles;

a cyan component comprising;

base particles; and

resin fine particles;

a magenta component comprising:

base particles; and

resin fine particles;

wherein an amount of charge of the yellow component is substantially the same as that of the cyan and the magenta components and,

a value of the ratio (Wy/Wc) of an amount of the resin fine particles in the yellow component (Wy) to an amount of the resin fine particles in the cyan component (Wc) based on 100 parts by mass of base particles, falls within a range from 1.1 to 5.0.

14. The toner set of claim 13 , a value of the ratio (Wy/Wm) of an amount of the resin fine particles in the yellow component (Wy) to an amount of the resin fine particles in the magenta component (Wm), based on 100 parts by mass of base particles, falls within a range from 1.1 to 5.0.

15. The toner set of claim 13 , wherein the yellow component further comprises titanium oxide.

16. The toner set of claim 13 wherein degradation of a charge maintaining characteristic of the yellow component of the toner is inhibited.