JP2834099B2 - Electrostatic inkjet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic ink jet recording apparatus, and more particularly to an electrostatic ink jet recording apparatus which performs recording by ejecting ink droplets containing toner particles onto a recording medium.

[0002]

2. Description of the Related Art A conventional electrostatic ink jet recording apparatus comprises a recording head having a plurality of discharge electrodes for discharging ink containing toner particles, and a platen disposed opposite to the recording head for transporting a recording medium. And a fixing means provided on the discharge side of the recording medium with respect to the counter electrode. Ink containing toner particles is ejected between the recording head and the counter electrode, and only the toner particles adhere to the recording medium. The toner particles adhering to the recording medium are heated and fixed on the recording medium by fixing means disposed on the discharge side of the recording medium.

[0003]

In the above-mentioned conventional electrostatic ink jet recording apparatus, the recording medium supplied between the discharge electrode and the counter electrode is conveyed in a state of contact with the counter electrode. When the recording medium is conveyed on the electrode and a minute floating occurs, the electrostatic field between the ejection electrode and the recording medium changes, and the ejection of the ink droplet becomes unstable.

Further, since the gap between the discharge electrode and the recording medium varies depending on the thickness of the recording medium being conveyed, there is a problem that printing variations occur due to the difference in the thickness of the recording medium.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent a minute floating caused by the conveyance of a recording medium on a counter electrode, to keep the gap between the recording head and the recording medium constant regardless of the thickness of the recording medium, It is an object of the present invention to provide an electrostatic ink jet recording apparatus that always obtains good print quality by quickly fixing toner particles attached to a recording medium.

[0006]

According to the present invention, there is provided an electrostatic ink jet recording apparatus comprising: a recording head having a plurality of ejection electrodes for ejecting ink containing toner particles; and a recording head opposed to the recording head. A counter electrode also serving as a platen for transporting the recording medium, a carriage moving along with the recording head along the recording medium, and a fixing unit disposed on the carriage and moving while being in contact with the recording medium. I have it.

[0007] In the electrostatic ink jet recording apparatus of the present invention, the fixing means is disposed very close to the recording head, and holds the recording medium such that a gap between the recording head and the recording medium is kept constant. You may make it move, pressing on the said counter electrode.

[0008] In the electrostatic ink jet recording apparatus of the present invention, the fixing means may be a heat roller incorporating a heater.

In the electrostatic ink jet recording apparatus according to the present invention, the fixing means may be disposed forward and backward with respect to the moving direction of the recording head.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention. Referring to FIG. 1, a recording apparatus according to the present invention includes a recording head 2 having a plurality of ejection electrodes 1 for discharging ink containing toner particles, and a recording medium 3 disposed opposite to the recording head 2. A counter electrode 4 also serving as a transport platen;
The carriage 5 includes a carriage 5 that moves along with the recording head 2 along the recording medium 3, and a fixing unit 6 that is disposed on the carriage 5 and moves while being in contact with the recording medium 3.

The counter electrode 4 is disposed at a position opposed to the recording head 2 in the ejection direction of the recording head 2 at a predetermined interval, and has a ground level or a minus level on the surface of the counter electrode 4. A bias voltage is always applied. The recording medium 3 is conveyed between the recording head 2 and the counter electrode 4 while being in contact with the counter electrode 4, so that the same voltage as that of the counter electrode 4 is applied. The recording head 2 has a guide shaft 7 arranged in parallel with the counter electrode 4.
It is mounted on a carriage 5 that can move upward. The fixing means 6 is formed of a material having good thermal conductivity incorporating a heater, and is disposed on both sides of the carriage 5 in the vicinity of the recording head 2 very near. When the carriage 5 moves, the recording head 2 and the recording medium 3 are moved with the carriage 5 while always pressing the recording medium 3 on the counter electrode 4 by a mechanism (not shown) while keeping the recording head 3 at a certain fixed gap.

In this embodiment, since the fixing means 6 is provided on both sides of the recording head 2, it is possible to fix a printed image while the recording head 2 moves in both the left and right directions. When printing is performed only in one direction, if the recording head 2 and the recording medium 3 are always maintained at a certain gap, the fixing unit 6 is disposed only behind the printing direction of the recording head 2. What you did.

FIG. 2 is a schematic diagram of the recording head 2. FIG. 2A is a perspective view, and FIG. 2B is a detailed sectional view of an ejection electrode portion. Referring to FIGS. 2A and 2B, the recording head 2 is an electrostatic ink jet recording head that discharges an ink 8 containing toner particles by an electrostatic field. As shown in FIG. A chamber A10 having
A chamber B12 having an ink discharge port 11, an ejection opening 13 formed in a part of the chamber A10 and the chamber B12 on the side of the counter electrode, a plurality of ejection electrodes 1 arranged near the ejection opening 13, A migration electrode 14 disposed at a position retracted from the electrode 1 with respect to the counter electrode 4 side.

The chamber A10 and the chamber B12 are
The ink supply port 9 and the ink discharge port 11 are connected to an ink tank (not shown) via a tube and a pump (not shown). The ink 8 is circulated in the recording head 2 so as to be discharged from the ink discharge port 11 to the ink tank through B12. In the vicinity of the discharge opening 13, a plurality of discharge electrodes 1 are arranged so as to protrude from the discharge opening 13 toward the counter electrode 4, and form a plurality of discharge points 15. Each discharge point 15 has a convex meniscus. While holding the ink 8.

The migrating electrode 14 is disposed at a position retracted from the discharge electrode 1 with respect to the counter electrode 4 in a state in which it is in contact with the ink 8, and a constant bias voltage is always applied. At the time of printing, a drive pulse voltage is applied to a desired discharge electrode 1, and an electrostatic field is generated between the discharge electrode 1 and the counter electrode 4. As a result, an electric field concentrates on the surface of the ink 8 forming the convex meniscus on the discharge point 15, and a Coulomb force acts on the toner particles in the ink by the electric field, and the Coulomb force overcomes the surface tension of the convex meniscus. Then, the ink 8 containing the toner particles on the discharge point 15 is discharged to the counter electrode 4 side and adheres to the recording medium 3 on the counter electrode 4.

FIG. 3 is an explanatory diagram of the operation of the fixing means 6.
The fixing unit 6 on the carriage 5 moves on the recording medium 3 while pressing the recording medium 3 on the counter electrode 4 so that the gap between the ejection electrode 1 and the recording medium 3 is always kept constant. The toner particles 16 ejected from the ejection point 15 and adhered onto the recording medium 3 are heated and pressed on the recording medium 3 by the fixing unit 6 arranged near the recording head 2.

As described above, the fixing means 6 is disposed on both sides in the vicinity of the recording head 2, and moves on the recording medium 3 while pressing the recording medium 3 on the counter electrode 4. The gap between the discharge electrode 1 and the recording medium 3 can be kept constant, and the toner particles 16 attached to the recording medium 3 can be quickly fixed.

[0019]

As described above, the present invention has a fixing means which is disposed on a carriage and moves while being in contact with a recording medium, and the fixing means is disposed very close to the recording head. The recording medium moves while being pressed against the counter electrode so as to keep the gap between the recording medium and the recording medium constant, so that the ink ejection is stabilized and the toner particles adhered to the recording medium are quickly fixed. This has the effect of always obtaining good print quality.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a schematic diagram of a recording head. FIG. 2A is a perspective view, and FIG. 2B is a detailed sectional view of an ejection electrode portion.

FIG. 3 is a diagram illustrating the operation of a fixing unit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 discharge electrode 2 recording head 3 recording medium 4 counter electrode 5 carriage 6 fixing means 7 guide shaft 8 ink 9 ink supply port 10 chamber A 11 ink discharge port 12 chamber B 13 discharge opening 14 migration electrode 15 discharge point 16 toner particles

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hitoshi Minemoto 7546 Yasuda, Kashiwazaki-shi, Niigata Niigata Nippon Electric Co., Ltd. (72) Inventor Hitoshi Takemoto 7546 Yasuda, Kashiwazaki-shi, Niigata Within (72) Inventor Yoshihiro Hagiwara 7546 Yasuda, Kashiwazaki-shi, Niigata Prefecture Within Niigata Nippon Electric Co., Ltd. References JP-A-10-805 (JP, A) JP-A-9-314867 (JP, A) JP-A-8-52898 (JP, A) JP-A-7-40534 (JP, A) (58) Survey Field (Int.Cl. ⁶ , DB name) B41J 2/06

Claims (4)

(57) [Claims] In an electrostatic ink jet recording apparatus for printing on a recording medium by applying an electric field to ink containing charged toner particles and ejecting ink droplets by Coulomb force acting on the toner particles, a plurality of ejection electrodes are provided. A recording head for discharging ink containing toner particles, a counter electrode disposed opposite to the recording head and serving also as a platen for transporting the recording medium, and the recording along the recording medium. An electrostatic ink jet recording apparatus comprising: a carriage that moves together with a head; and a fixing unit that is disposed on the carriage and moves while being in contact with the recording medium. 2. The fixing device according to claim 1, wherein the fixing unit is disposed very close to the recording head, and moves the recording medium while pressing the recording medium on the counter electrode so as to maintain a constant gap between the recording head and the recording medium. The electrostatic ink jet recording apparatus according to claim 1, wherein 3. The electrostatic ink jet recording apparatus according to claim 1, wherein the fixing unit is a heat roller incorporating a heater. 4. An electrostatic ink jet recording apparatus according to claim 1, wherein said fixing means is disposed forward and backward with respect to a moving direction of the recording head.