Image forming apparatus including an image forming unit with white developer

1. An image forming apparatus, comprising:

a first image forming unit configured to form a white developer image on a recording medium using a white developer;

at least one second image forming unit configured to form at least one single-color developer image on said recording medium using at least one single-color developer other than said white developer; and

a fixing unit configured to fix said white developer image and said at least one single-color developer image to said recording medium so as to form a white image and at least one single-color image,

wherein said white image has a haze value that is higher than that of said at least one single-color image, and

wherein said white developer has a softening temperature that is higher than that of said at least one single-color developer.

2. The image forming apparatus according to claim 1 , wherein said haze value of said white image is higher than or equal to 88%, and wherein said haze value of each of said at least one single-color image is lower than or equal to 70%.

3. The image forming apparatus according to claim 1 , wherein said white developer image and said at least one single-color developer image are superimposed with each other on said recording medium.

4. The image forming apparatus according to claim 1 , wherein said first image forming unit forms said white developer image in such a manner that an amount of said white developer per unit area is in a range of 0.8-1.1 mg/cm 2 , and

wherein said at least one second image forming unit forms said at least one single-color developer image in such a manner that an amount of said single-color developer per unit area is in a range of 0.4-0.6 mg/cm 2 .

5. The image forming apparatus according to claim 1 , wherein said first image forming unit forms said white developer image in such a manner that an amount of said white developer per unit area is in a range of 0.9-1.1 mg/cm 2 , and

wherein said at least one second image forming unit forms said at least one single-color developer image in such a manner that an amount of said single-color developer per unit area is in a range of 0.4-0.5 mg/cm 2 .

6. An image forming apparatus, comprising:

a first image forming unit configured to form a white developer image on a recording medium using a white developer;

at least one second image forming unit configured to form at least one single-color developer image on said recording medium using at least one single-color developer other than said white developer; and

a fixing unit configured to fix said white developer image and said at least one single-color developer image to said recording medium so as to form a white image and at least one single-color image,

wherein said white developer has a softening temperature that is higher than that of said at least one single-color developer.

7. The image forming apparatus according to claim 6 , wherein said white developer image and said at least one single-color developer image are superimposed with each other on said recording medium.

8. The image forming apparatus according to claim 7 , wherein said white developer image is formed on said recording medium, and said at least one single-color developer image is formed on said white developer image.

9. The image forming apparatus according to claim 7 , wherein said at least one single-color developer image is formed on said recording medium, and said white developer image is formed on said at least one single-color developer image.

10. The image forming apparatus according to claim 6 , wherein said recording medium has a conveying direction, and wherein said first image forming unit is disposed on an upstream side of said at least one second image forming unit in the conveying direction of said recording medium.

11. The image forming apparatus according to claim 6 , wherein said recording medium has a conveying direction, and wherein said first image forming unit is disposed on a downstream side of said at least one second image forming unit in the conveying direction of said recording medium.

12. The image forming apparatus according to claim 6 , further comprising a transfer unit disposed so as to lace said first image forming unit and said at least one second image forming unit, said transfer unit having a belt.

13. The image forming apparatus according to claim 12 , wherein said belt has a region facing said first image forming unit and said at least one second image forming unit.

14. The image forming apparatus according to claim 13 , wherein said belt has a moving direction, and wherein said first image forming unit is disposed on an upstream side of said at least one second image forming unit in the moving direction of said belt.

15. The image forming apparatus according to claim 14 , wherein said belt conveys said recording medium.

16. The image forming apparatus according to claim 13 , wherein said belt has a moving direction, and wherein said first image forming unit is disposed on a downstream side of said at least one second image forming unit in the moving direction of said belt.

17. The image forming apparatus according to claim 16 , wherein said belt conveys said recording medium.

18. The image forming apparatus according to claim 6 , wherein, when said recording medium has a surface temperature Mt (° C.) at said fixing unit, said at least one single-color developer has a maximum softening temperature Tsmax (° C.) and a minimum outflow starting temperature Tfmin (° C.) that satisfy:

Ts max(° C.)≦ Mt (° C.)≦ Tf min(° C.).

19. The image forming apparatus according to claim 6 , wherein said first image forming unit forms said white developer image in such a manner that an amount of said white developer per unit area is in a range of 0.8-1.1 mg/cm 2 , and wherein said at least one second image forming unit forms said at least one single-color developer image in such a manner that an amount of said single-color developer per unit area is in a range of 0.4-0.6 mg/cm 2 .

20. The image forming apparatus according to claim 6 , wherein said first image forming unit forms said white developer image in such a manner that an amount of said white developer per unit area is in a range of 0.9-1.1 mg/cm 2 , and wherein said at least one second image forming unit forms said at least one single-color developer image in such a manner that an amount of said single-color developer per unit area is in a range of 0.4-0.5 mg/cm 2 .

21. The image forming apparatus according to claim 6 , wherein said white developer includes a white toner containing at least a binder resin and a white coloring agent.

22. The image forming apparatus according to claim 21 , wherein said white coloring agent contains metallic oxide.

23. The image forming apparatus according to claim 22 , wherein said metallic oxide contains titanium oxide.

24. The image forming apparatus according to claim 6 , wherein said at least one single-color image has a glossiness that is higher than 30%.

25. The image forming apparatus according to claim 1 , wherein an outflow starting temperature of said white developer is higher than an outflow starling temperature of said at least one single-color developer.

26. The image forming apparatus according to claim 6 , wherein an outflow starting temperature of said white developer is higher than an outflow starting temperature of said at least one single-color developer.