Ink-jet recording head and ink-jet recorder

• US 6,604,816 B1
• Filed: 12/28/2001
• Issued: 08/12/2003
• Est. Priority Date: 06/30/1999
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Masuda, Kazuhito, Okano, Mamoru, Fukano, Yoshinobu, Yonekura, Seiji, Igawa, Tatsuo
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): Do, An H.
• Application Number:
  US10/019,266
• Time in Patent Office: 592 Days
• Field of Search: 347/54, 347/55, 347/20, 347/40, 347/43, 347/100, 347/68-72, 347/56-62
• US Class Current: 347/54
• CPC Class Codes: B41J 2/06 by electric or magnetic field
• CPC Class Codes: B41J 2/17503 Ink cartridges
• CPC Class Codes: B41J 2/17513 Inner structure
• CPC Class Codes: B41J 2/17566 Ink level or ink residue control
• CPC Class Codes: B41J 2002/061 Ejection by electric field of ink or of toner particles contained in ink
• CPC Class Codes: B41J 2202/12 with ink circulating through the whole print head

Abstract

The recording electrodes and the control electrodes of an ink jet recording head are alternately arranged on a substrate. Ink in which coloring material is distributed in a solvent is supplied to the recording electrode so that the ink can flow in the direction of the length of the recording electrode. An ink circulation part is provided for collecting surplus ink from the point of the recording electrode from which ink is discharged. As a result, an ink jet recorder, which can produce a high definition image without shifting the ink impact position on the recording medium, can be produced.

Claims

1. An ink jet recording head comprising:

a substrate,

a plurality of recording electrodes arranged on said substrate,

a plurality of control electrodes arranged so as to sandwich each of said recording electrodes,

an ink circulation part for supplying ink which contains coloring material in solvent to said recording electrodes to flow it in a direction of length of said each recording electrode, and collecting said ink from a point of said each recording electrode.

2. The ink jet recording head according to claim 1, wherein a shroud of a dielectric substance is provided between said each recording electrode and said each control electrode, and between said each control electrode and an ink channel.

3. The ink jet recording head according to claim 1, wherein said each recording electrode projects from the edge of said substrate.

4. The ink jet recording head according to claim 3, wherein said each control electrode project from the edge of said substrate, and the projection amount of said each control electrode is smaller than that of said each recording electrode.

5. The ink jet recording head according to any one of claims 1 to 4, wherein said each recording electrode is covered by the insulation coating material.

6. Ink jet recording head according to claim 1, wherein an angle θ

of said ink collection channel is in the following ranges

7. The ink jet recording head according to claim 1, wherein height s of the point of said control electrode is equal to or more than height h of the ink channel.

21. The ink jet recording head according to any one of claims 1, 8 and 9, wherein the electrical resistivity of said ink is 10⁷ Ω

·

cm or more, the surface tension 30 mN/m or less, the viscosity 1-10 mpa·

s, the mean particle size of coloring material 50-500 nm, the surface density of charges of the coloring material 1-100 μ

C/m², and the content of coloring material particles 1-10 percent by weight.

22. The ink jet recording head according to claim 21, wherein pigments are used as the coloring material.

23. The ink jet recording head according to claim 21, wherein isopar is used as the solvent.

24. The ink jet recording head according to claim 21, wherein silicone oil is used as the solvent.

8. An ink jet recording head comprising:

a substrate,

a plurality of recording electrodes arranged on said substrate,

a plurality of control electrodes arranged so as to sandwich each of said recording electrodes, and

an ink circulation part having ink supply channel provided to flow ink which contains coloring material in solvent to said recording electrodes in a direction of length of said each recording electrode, and ink collection channel for collecting the ink from a point of said each recording electrode that said ink is discharged to the lower side of said each recording electrode,

wherein the shape of ink meniscus formed in the vicinity of the point of said each recording electrode is controlled by giving the airflow directly to said ink meniscus.

10. The ink jet recording head according to claim 8 or 9, further comprising:

a migration electrode provided at a rear end where ink of said each recording electrode is supplied, for increasing an amount of said coloring material in ink collected in the point of said each recording electrode.

11. The ink jet recording head according to claim 8 or 9, wherein an angle α

of the point of said each recording electrode is formed within the following ranges

12. The ink jet recording head according to claim 8 or 9, further comprising a plurality of ink discharge parts at least including said plural recording electrodes and said plural control electrodes, and

wherein each of said plural ink discharge parts is arranged with being overlapped like a zigzag, and the ink supply and the ink collection for said plural recording electrode are shared.

13. The ink jet recording head according to claim 8 or 9, further comprising a capping member for covering said plural recording electrodes, and ink holder formed between said capping member and the point of said each recording electrode.

14. The ink jet recording head according to claim 8 or 9, further comprising an ink container connected with said ink collection channel, having an ink layer for the ink collected from said ink collection channel and an air layer for air, and

wherein the ink is collected by decompressing the air layer in said ink container.

15. The ink jet recording head according to claim 14, further comprising a vacuum pump connected to said ink container, for decompressing said air layer.

16. The ink jet recording head according to claim 8 or 9, wherein said ink collection channel has a space on the side near the point of said each recording electrode, and narrows at a certain angle as it becomes far from the point of said each recording electrode.

17. The ink jet recording head according to claim 8 or 9, wherein a ratio of height h and width w of said ink supply channel satisfies the following relationship

18. The ink jet recording head according to claim 8 or 9, wherein a ratio of height h of said ink supply channel and projection amount 1 of said control electrode from said substrate satisfies the following relationship

19. The ink jet recording head according to claim 8 or 9, wherein a ratio of point thickness t and point curvature r of said recording electrode satisfies the following relationship

20. The ink jet recording head according to claim 8 or 9, wherein a ratio of projection amount I of said control electrode from said substrate and projection amount L of said recording electrode from said substrate satisfies the following relationship

9. An ink jet recording head comprising:

a substrate,

a plurality of recording electrodes arranged on said substrate,

a plurality of control electrodes arranged so as to sandwich each of said recording electrodes, and

an ink circulation part having ink supply channel provided to flow ink which contains coloring material in solvent to said recording electrodes in a direction of length of said each recording electrode, and ink collection channel for collecting the ink from a point of said each recording electrode that said ink is discharged to the lower side of said each recording electrode,

wherein said ink collection channel passes air with ink which flows from the vicinity of the point of said each recording electrode.

25. An ink jet recording head comprising:

a substrate,

a plurality of recording electrodes arranged on said substrate,

a plurality of control electrodes arranged so as to sandwich each of said recording electrodes, and

an ink circulation part having ink supply channel provided to flow ink which contains coloring material in solvent to said recording electrodes in a direction of length of said each recording electrode, ink collection channel for collecting the ink from a point of said each recording electrode that said ink is discharged to the lower side of said each recording electrode, and ink flow modulating room for modulating an amount of the ink flow to said each recording electrode through said ink supply channel, and

wherein said ink collection channel passes air with ink which flows from the vicinity of the point of said each recording electrode, and the ink from said ink flow modulating room to said plural recording electrodes is supplied according to a head difference by a position where said ink flow modulating room and said plural recording electrodes are arranged.

26. The ink jet recording head according to claim 25, further comprising an ink replenishment container connected with said ink container, for storing ink thicker than ink concentration in said ink container, and

a concentration ink adjustment part for adjusting the supply of thick ink from said ink replenishment container to said ink container.

27. An ink jet recording head comprising:

a substrate,

a plurality of recording electrodes arranged on said substrate,

a plurality of control electrodes arranged so as to sandwich each of said recording electrodes, and

an ink circulation part having ink supply channel provided to flow ink which contains coloring material in solvent to said recording electrodes in a direction of length of said each recording electrode, and ink collection channel for collecting the ink from a point of said each recording electrode that said ink is discharged to a lower side of said each recording electrode along a part of said substrate,

wherein said ink collection channel has a space provided with respect to said substrate to flow the ink and the air collected from said each recording electrode, and

said space g is within the following range

28. An ink jet recording head comprising:

a plurality of recording electrodes arranged on a substrate,

a plurality of control electrodes arranged so as to sandwich each of said recording electrodes, and

an ink circulation part having ink supply channel provided to flow ink which contains coloring material in solvent to said recording electrodes in a direction of length of said each recording electrode, ink collection channel for collecting the ink from a point of said each recording electrode that said ink is discharged to a lower side of said each recording electrode, and ink flow modulating room for modulating an amount of the ink flow to said each recording electrode, and

wherein a weight % of an insoluble material which includes the coloring material contained in an ink drop discharged from the point of said recording electrode is less than a weight % of the solvent.

29. An ink jet recording head comprising:

a plurality of recording electrodes arranged on a substrate,

a plurality of control electrodes arranged so as to sandwich each of said recording electrodes,

an ink circulation part having ink supply channel provided to flow ink which contains coloring material in solvent to said recording electrodes in a direction of length of said each recording electrode, ink collection channel for collecting the ink from a point of said each recording electrode that said ink is discharged to a lower side of said each recording electrode, and ink flow modulating room for modulating an amount of the ink flow to said each recording electrode, and

a pulse voltage generation circuit for applying the pulse voltage to said plural recording electrodes, and

wherein said substrate, said plural recording electrodes, said plural control electrodes, said pulse voltage generation circuit, and said ink circulation part are integrated together.

30. An ink jet recording head comprising:

a plurality of recording electrodes arranged on a substrate,

a plurality of control electrodes arranged so as to sandwich each of said recording electrodes,

an ink circulation part having ink supply channel provided to flow ink which contains coloring material in solvent to said recording electrodes in a direction of length of said each recording electrode, ink collection channel for collecting the ink from a point of said each recording electrode that said ink is discharged to a lower side of said each recording electrode, and ink flow modulating room for modulating an amount of the ink flow to said each recording electrode,

a bias supply for applying an electrode bias to said plural recording electrodes and said plural control electrodes,

a pulse voltage generation circuit connected to each of said plural recording electrodes,

a recording medium carrying passage for carrying a recording medium, and

a common electrode opposed to said plural recording electrodes.

31. An ink jet recording head comprising:

a substrate,

a plurality of recording electrodes arranged on said substrate,

a plurality of control electrodes arranged so as to sandwich each of said recording electrodes,

an ink circulation part for supplying ink which contains coloring material in solvent to said recording electrodes to flow the ink in a direction of a length of respective ones of said recording electrodes and for collecting the ink from a tip of respective ones of the recording electrodes, said ink circulation part including ink channels provided for each recording electrode, the ink channels being at least partially delimited by shrouds.

32. The ink jet recording head according to claim 31, wherein the shrouds are shrouds of a dielectric substance.