Toner for electrostatic charge image developing, developer for electrostatic charge image developing, and image forming apparatus

1. A toner for electrostatic charge image developing, comprising a core layer which contains a first binder resin and a coloring agent, and a shell layer which contains a second binder resin and covers the core layer, characterized in that the following equation (1) and the following equation (2) are satisfied,

2.0×10 5 ≦G ′(60)≦4.0×10 6   Equation (1)

10 ≦G ′(60)/ G ′(80)≦40  Equation (2)

wherein, in the equation (1) and the equation (2), G′(60) represents a storage elastic modulus (Pa) of the toner for electrostatic charge image developing measured under the conditions of a temperature of 60° C., a vibration frequency of 6.28 rad/sec, and a strain amount of 0.01 to 0.5%, and G′(80) represents a storage elastic modulus (Pa) of the toner for electrostatic charge image developing measured under the conditions of a temperature of 80° C., a vibration frequency of 6.28 rad/sec, and a strain amount of 0.01 to 0.5%.

2. The toner for electrostatic charge image developing of claim 1 , wherein two maximum values of tangential loss measured under the conditions of a vibration frequency of 6.28 rad/sec and a strain amount of 0.01 to 0.5% are present in a range of not lower than 30° C. and not higher than 90° C.

3. The toner for electrostatic charge image developing of claim 1 , wherein a difference ΔSP (|SPc−SPs|) between a solubility parameter SPc of the first binder resin and a solubility parameter SPs of the second binder resin is in a range of 0.2 to 0.6.

4. The toner for electrostatic charge image developing of claim 1 , further comprising an inorganic compound in a range of 0.3 to 3 parts by mass relative to 100 parts by mass of toner particles.

5. The toner for electrostatic charge image developing of claim 1 , further comprising a releasing agent.

6. A developer for electrostatic charge image developing, comprising a toner for electrostatic charge image developing having a core layer which contains a first binder resin and a coloring agent, and a shell layer which contains a second binder resin and covers the core layer, and satisfies the following equation (1) and the following equation (2), and a carrier,

2.0×10 5 ≦G ′(60)≦4.0×10 6   Equation (1)

10 ≦G ′(60)/ G ′(80)≦40  Equation (2)

wherein, in the equation (1) and the equation (2), G′(60) represents a storage elastic modulus (Pa) of the toner for electrostatic charge image developing measured under the conditions of a temperature of 60° C., a vibration frequency of 6.28 rad/sec, and a strain amount of 0.01 to 0.5%, and G′(80) represents a storage elastic modulus (Pa) of the toner for electrostatic charge image developing measured under the conditions of a temperature of 80° C., a vibration frequency of 6.28 rad/sec, and a strain amount of 0.01 to 0.5%.

7. The developer for electrostatic charge image developing of claim 6 , wherein a volume specific resistance of the carrier is in a range of 10 6 to 10 13 Ω·cm at 1,000V.

8. An image forming apparatus, comprising an image carrying body, an charging means for charging a surface of the image carrying body, an exposing means for forming an electrostatic latent image on a surface of the charged image carrying body based on image information, a developing means for developing the electrostatic latent image with a developer containing a toner to form a toner image on a surface of the image carrying body, a transferring means for transferring the toner image onto a surface of a recording medium from the surface of the image carrying body, and a fixing means for fixing the toner image transferred onto the surface of the recording medium by heating and pressing, to form an image, wherein the toner is a toner for electrostatic charge image developing having a core layer which contains a first binder resin and a coloring agent, and a shell layer which contains a second binder resin and covers the core layer, and satisfies the following equation (1) and the following equation (2),

2.0×10 5 ≦G ′(60)≦4.0×10 6   Equation (1)

10 ≦G ′(60)/ G ′(80)≦40  Equation (2)

and wherein, in the equation (1) and the equation (2), G′(60) represents a storage elastic modulus (Pa) of the toner for electrostatic charge image developing measured under the conditions of a temperature of 60° C., a vibration frequency of 6.28 rad/sec, and a strain amount of 0.01 to 0.5%, and G′(80) represents a storage elastic modulus (Pa) of the toner for electrostatic charge image developing measured under the conditions of a temperature of 80° C., a vibration frequency of 6.28 rad/sec, and a strain amount of 0.01 to 0.5%.

9. The image forming apparatus of claim 8 , wherein the fixing means includes a heating means having at least function of heating the toner image, and has a function of maintaining the temperature of the heating means at a temperature lower than the temperature during fixing when there is a prolonged period where an image is not formed.

10. The image forming apparatus of claim 8 , wherein an actual average fixing temperature of the fixing means is 120° C. or lower.