Image-forming process and image-forming apparatus using flash fusing

1. An image-forming process for forming a full-color image comprising:

forming a full-color toner image by supplying at least a cyan toner, a magenta toner and a yellow toner onto a recording medium; and

fixing the toner image on the recording medium by flash fusing, wherein:

each of the cyan toner, the magenta toner and the yellow toner contains an infrared absorbent;

the cyan toner is supplied so that out of the cyan toner, the magenta toner and the yellow toner, the cyan toner is positioned in an uppermost layer in areas of the toner image where the cyan toner is present; and

the flash fusing is performed by a delayed light emission process wherein a plurality of flash lamps emit lights at a time interval, wherein the content amount of the infrared absorbent in the cyan toner is smaller than the respective content amounts of the infrared absorbent in the magenta toner and the yellow toner.

2. The image-forming process according to claim 1 , wherein a total emission energy of the plurality of flash lamps is in a range of 3.0 to 7.0 J/cm 2 ; the full-color image includes an image portion containing a black toner; and the black toner is supplied so that the black toner is positioned in a lowermost layer in areas of the toner image where the black toner is present.

3. The image-forming process according to claim 2 , wherein the cyan toner, the magenta toner, the yellow toner and the black toner are supplied so that they are superimposed in the order of the cyan toner, magenta toner, the yellow toner and the black toner from the uppermost layer of the toner image.

4. The image-forming process according to claim 3 , wherein the full-color image includes an image portion containing an invisible toner; and the cyan toner, the magenta toner, the yellow toner, the invisible toner and the black toner are supplied so that they are superimposed in the order of the cyan toner, the magenta toner, the yellow toner, the invisible toner and the black toner from the uppermost layer of the toner image.

5. The image-forming process according to claim 1 , wherein the full-color image includes an image portion containing an invisible toner, and the invisible toner is supplied so that the invisible toner is positioned in a lowermost layer in areas of the toner image where the invisible toner is present.

6. The image-forming process according to claim 1 , wherein the infrared absorbent is selected from a cyanine compound, a merocyanine compound, a benzene thiol-based metal complex, a mercaptophenol-based metal complex, an aromatic diamine-based metal complex, a nickel complex compound, a phthalocyanine compound, an anthraquinone compound, ytterbium oxide, ytterbium phosphate, a naphthalocyanine compound, an aminium compound, or a diimmonium compound.

7. The image-forming process according to claim 1 , wherein the infrared absorbent satisfies one of the following conditions, (I) and (II):

(I) the infrared absorbent is an organic infrared absorbent, and the amount of the organic infrared absorbent added is 0.05 to 5 parts by mass with respect to 100 parts by weight of the toner; or

(II) the infrared absorbent is an inorganic infrared absorbent, and the amount of the inorganic infrared absorbent added is 5 to 70 parts by mass with respect to 100 parts by mass of the toner.

8. The image-forming process according to claim 1 , wherein the maximum value of an infrared ray absorbance of the cyan toner in a wavelength range of 800 to 1,100 nm is smaller than the respective maximum values of an infrared ray absorbance of the yellow toner and the magenta toner in the wavelength range of 800 to 1,100 nm.

9. The image-forming process according to claim 1 , wherein a processing speed is 200 mm/sec or more.

10. The image-forming process according to claim 1 , wherein a processing speed is 1,000 mm/sec or more.

11. An image-forming process for forming a full-color image comprising:

forming a full-color toner image by supplying at least a cyan toner, a magenta toner and a yellow toner onto a recording medium; and

fixing the toner image on the recording medium by flash fusing, wherein:

each of the cyan toner, the magenta toner and the yellow toner contains an infrared absorbent;

the yellow toner is supplied so that out of the cyan toner, the magenta toner and the yellow toner, the yellow toner is positioned in a lowermost layer in areas of the toner image where the yellow toner is present; and

the flash fusing is performed by a delayed light emission process wherein a plurality of flash lamps emit lights at a time interval, wherein the content amount of the infrared absorbent in the cyan toner is smaller than the respective content amounts of the infrared absorbent in the magenta toner and the yellow toner.

12. The image-forming process according to claim 11 , wherein a total emission energy of the plurality of flash lamps is 1.0 J/cm 2 or more and less than 3.0 J/cm 2 ; the full-color image includes an image layer containing a black toner; and the black toner is supplied so that the black toner is positioned in an uppermost layer in areas of the toner image where the black toner is present.

13. The image-forming process according to claim 12 , wherein the black toner, the cyan toner, the magenta toner and the yellow toner are supplied so that they are superimposed in the order of the black toner, the cyan toner, the magenta toner and the yellow toner from the uppermost layer of the toner image.

14. The image-forming process according to claim 13 , wherein the full-color image includes an image portion containing an invisible toner; and the black toner, the cyan toner, the magenta toner, the yellow toner and the invisible toner are supplied so that they are superimposed in the order of the black toner, the cyan toner, the magenta toner, the yellow toner and the invisible toner from the uppermost layer of the toner image.

15. The image-forming process according to claim 11 , wherein the full-color image includes an image portion containing an invisible toner; and the invisible toner is supplied so that the invisible toner is positioned in the lowermost layer in areas of the toner image where the invisible toner is present.

16. The image-forming process according to claim 11 , wherein the infrared absorbent is selected from a cyanine compound, a merocyanine compound, a benzene thiol-based metal complex, a mercaptophenol-based metal complex, an aromatic diamine-based metal complex, a nickel complex compound, a phthalocyanine compound, an anthraquinone compound, ytterbium oxide, ytterbium phosphate, a naphthalocyanine compound, an aminium compound, or a diimmonium compound.

17. The image-forming process according to claim 11 , wherein the infrared absorbent satisfies one of the following conditions, (I) and (II):

(I) the infrared absorbent is an organic infrared absorbent, and the amount of the organic infrared absorbent added is 0.05 to 5 parts by mass with respect to 100 parts by mass of the toner; and

(II) the infrared absorbent is an inorganic infrared absorbent, and the amount of the inorganic infrared absorbent added is 5 to 70 parts by mass with respect to 100 parts by mass of the toner.

18. The image-forming process according to claim 11 , wherein the maximum value of an infrared ray absorbance of the cyan toner in a wavelength range of 800 to 1,100 nm is smaller than the respective maximum values of an infrared ray absorbance of the yellow toner and the magenta toner in the wavelength range of 800 to 1,100 nm.

19. The image-forming process according to claim 11 , wherein a processing speed is 200 mm/sec or more.

20. The image-forming process according to claim 11 , wherein a processing speed is 1,000 mm/sec or more.

21. An image-forming apparatus for forming a full-color toner image, comprising:

a toner image-forming device for forming a full-color toner image by supplying at least a cyan toner, a magenta toner and a yellow toner onto a recording medium; and

an image fixing device for fixing the toner image on the recording medium by flash fusing, wherein:

each of the cyan toner, the magenta toner and the yellow toner contains an infrared absorbent;

the toner image-forming device supplies the toners so that out of the cyan toner, the magenta toner and the yellow toner, the cyan toner is positioned in an uppermost layer in areas of the toner image where the cyan toner is present; and

the image fixing device is a flash fusing device having a plurality of flash lamps capable of flash fusing by a delayed light emission process of emitting lights from the plurality of flash lamps at a time interval, wherein the content amount of the infrared absorbent in the cyan toner is smaller than the respective content amounts of the infrared absorbent in the magenta toner and the yellow toner.

22. An image-forming apparatus for forming a full-color toner image, comprising:

a toner image-forming device for forming a full-color toner image by supplying at least a cyan toner, a magenta toner and a yellow toner onto a recording medium; and

an image fixing device for fixing the toner image on the recording medium by flash fusing, wherein:

each of the cyan toner, the magenta toner and the yellow toner contains an infrared absorbent;

the toner image-forming device supplies the toners so that out of the cyan toner, the magenta toner and the yellow toner, the yellow toner is positioned in a lowermost layer in areas of the toner image where the yellow toner is present; and

the image fixing device is a flash fusing device having a plurality of flash lamps capable of flash fusing by a delayed light emission process of emitting lights from the plurality of flash lamps at a time interval, wherein the content amount of the infrared absorbent in the cyan toner is smaller than the respective content amounts of the infrared absorbent in the magenta toner and the yellow toner.