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

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).

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 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).

A method of maintaining printing quality during repeated use comprising:

• providing a toner having:
• a yellow component comprising:
• a monoazo pigment;
• base particles;
• and
• resin fine particles;
• a cyan component comprising;
• resin fine particles;
• and
• a magenta component comprising:
• resin fine particles;
• charging a image carrier by a charging unit;
• forming an electrostatic latent image on the charged image carrier by an exposing unit;
• developing the electrostatic latent image on the image carrier to a toner image with a developer from a developing unit;
• transferring the toner image to a recording medium by a transferring portion;
• and
• maintaining an optimal charge characteristic of the yellow component of the toner.

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 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.