Ink set and image forming device

Patent metadata

Field	Value
Publication number	US-10618331-B2
Application number	US-201916293694-A
Country	US
Kind code	B2
Filing date	Mar 6, 2019
Priority date	Mar 8, 2018
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

An ink set comprises black ink having a static surface tension A and yellow ink having a static surface tension B, wherein the static surface tension A is by 0.6 mN/m or more greater than the static surface tension B, wherein the ink set is used in an image forming device including an inkjet head including a nozzle plate including a first nozzle array and a second nozzle array disposed adjacent to the first nozzle array, the first nozzle array including multiple first nozzles configured to discharge the black ink and a second nozzle array including multiple second nozzles configured to discharge the yellow ink, wherein each nozzle of the multiple first nozzles and the multiple second nozzles has a cylindrical portion having a length of 25 μm or longer along an axial direction with an opening on an ink discharging side of the nozzle plate.

First claim

What is claimed is:

1. An ink set comprising:
black ink having a static surface tension A; and
yellow ink having a static surface tension B,
wherein the static surface tension A is by 0.6 mN/m or more greater than the static surface tension B,
wherein the ink set is used in an image forming device including an inkjet head including a nozzle plate including a first nozzle array and a second nozzle array disposed adjacent to the first nozzle array, the first nozzle array including multiple first nozzles configured to discharge the black ink and a second nozzle array including multiple second nozzles configured to discharge the yellow ink,
wherein each nozzle of the multiple first nozzles and the multiple second nozzles has a cylindrical portion having a length of 25 μm or longer along an axial direction with an opening on an ink discharging side of the nozzle plate.

2. The ink set according to claim 1 , wherein the length is 30 μm or longer.

3. The ink set according to claim 1 ,
wherein the nozzle plate further includes respective first introduction portions configured to communicate with the multiple first nozzles and respective second introduction portions configured to communicate with the multiple second nozzles,
wherein a diameter of the respective first introduction portions is larger than a diameter of the multiple first nozzles and a diameter of the respective second introduction portions is larger than a diameter of the multiple second nozzles.

4. The ink set according to claim 1 ,
wherein the static surface tension A is by 0.7 mN/m or more greater than the static surface tension B.

5. The ink set according to claim 1 ,
wherein the following inequality is satisfied:
0.7 mN/m≤(the static surface tension A )−(the static surface tension B )≤1.0 mN/m.

6. The ink set according to claim 1 ,
wherein each of the black ink and the yellow ink comprises an acetylene glycol compound, triethylene glycol monobutyl ether, and glycerin,
wherein the following inequalities are satisfied:
|(proportion of the acetylene glycol compound in the black ink)−(proportion of the acetylene glycol compound in the yellow ink)|≤2 percent by mass,

|(proportion of triethylene glycol monobutyl ether in the black ink)−(proportion of triethylene glycol monobutyl ether in the yellow ink)|≤2 percent by mass,

|(proportion of glycerin in the black ink)−(proportion of glycerin in the yellow ink)|≤2 percent by mass.

7. The ink set according to claim 1 , wherein the ink head comprises a line-type inkjet head.

8. An image forming device comprising:
black ink having a static surface tension A;
yellow ink having a static surface tension B; and
an inkjet head including a nozzle plate including a first nozzle array and a second nozzle array disposed adjacent to the first nozzle array, the first nozzle array including multiple first nozzles configured to discharge the black ink and a second nozzle array including multiple second nozzles configured to discharge the yellow ink,
wherein each nozzle of the multiple first nozzles and the multiple second nozzles has a cylindrical portion having a length of 25 μm or longer along an axial direction with an opening on an ink discharging side of the nozzle plate,
wherein the static surface tension A is by 0.6 mN/m or more greater than the static surface tension B.

9. The image forming device according to claim 8 ,
wherein the length is 30 μm or longer.

10. The image forming device according to claim 8 ,
wherein the nozzle plate further includes respective first introduction portions configured to communicate with the multiple first nozzles and respective second introduction portions configured to communicate with the multiple second nozzles,
wherein a diameter of the respective first introduction portions is larger than a diameter of the multiple first nozzles and a diameter of the respective second introduction portions is larger than a diameter of the multiple second nozzles.

11. The image forming device according to claim 8 ,
wherein the static surface tension A is by 0.7 mN/m or more greater than the static surface tension B.

12. The image forming device according to claim 8 , wherein the following inequality is satisfied:
0.7 mN/m≤(the static surface tension A )−(the static surface tension B )≤1.0 mN/m.

13. The image forming device according to claim 8 ,
wherein each of the black ink and the yellow ink comprises an acetylene glycol compound, triethylene glycol monobutyl ether, and glycerin,
wherein the following inequalities are satisfied:
|(proportion of the acetylene glycol compound in the black ink)−(proportion of the acetylene glycol compound in the yellow ink)|≤2 percent by mass,

|(proportion of triethylene glycol monobutyl ether in the black ink)−(proportion of triethylene glycol monobutyl ether in the yellow ink)|≤2 percent by mass,

|(proportion of glycerin in the black ink)−(proportion of glycerin in the yellow ink)|≤2 percent by mass.

14. The image forming device according to claim 8 , wherein the ink head comprises a line-type inkjet head.

15. An ink set comprising:
dark color ink having a static surface tension A; and
light color ink having a static surface tension B,
wherein the static surface tension A is by 0.6 mN/m or more greater than the static surface tension B,
wherein the ink set is used in an image forming device including an inkjet head including a nozzle plate including a first nozzle array and a second nozzle array disposed adjacent to the first nozzle array, the first nozzle array including multiple first nozzles configured to discharge the dark color ink and a second nozzle array including multiple second nozzles configured to discharge the light color ink
wherein each nozzle of the multiple first nozzles and the multiple second nozzles has a cylindrical portion having a length of 25 μm or longer along an axial direction with an opening on an ink discharging side of the nozzle plate.

Assignees

• Watanabe Takashi
• Hatakeyama Taku
• Tadokoro Kaoru
• Oyamatsu Sho
• Inoue Tomohiro
• Goto Hiroshi
• Kumai Mio
• Ricoh Co Ltd

Inventors

• Watanabe Takashi
• Hatakeyama Taku
• Tadokoro Kaoru
• Oyamatsu Sho
• Inoue Tomohiro
• Gotou Hiroshi
• Kumai Mio

Classifications

• B41J2002/1655

  with wiping surface parallel with nozzle plate and mounted on reels, e.g. cleaning ribbon cassettes · CPC title

• C09D11/38

  characterised by non-macromolecular additives other than solvents, pigments or dyes · CPC title

• B41J2/16535 Primary

  using wiping constructions (B41J2/16552 takes precedence) · CPC title

• C09D11/40

  Ink-sets specially adapted for multi-colour inkjet printing · CPC title

• C09D11/033

  characterised by the solvent · CPC title