JPS60210461A - Inkjet recorder - Google Patents

Abstract

PURPOSE:To form an ink drop of an even particle size with a higher injection efficiency of electric charge by arranging a recording electrode surface with a sufficiently larger area than the ink jet port to face the ink jet port itself. CONSTITUTION:The ink filled into an ink tank 11 at a fixed level is fed to a recording head A with a pump 12. The ink fed circulates over the circumferential surface of a frame 15 to fill between a recording electrode 16 and an ink jet port 14. As a high-voltage pulse 300V is applied to the recording electrode 16 according to recording information, electric charges in the ink concentrate near the injecting ink jet port 14 so that ink drops jet receiving an electrostatic force. The ink drops jetted is accelerated by a static electric field generated by a high voltage of 2kV applied between the recording electrode 16 and the opposed electrode 18 to attach to a recording paper 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention uses a plate-shaped electrode plate in a recording electrode to which a high-voltage pulse corresponding to one image information is applied in order to ensure a contact area with ink.

The present invention relates to an inkjet recording device that makes electric field distribution in ink uniform and improves charge injection efficiency.

[Prior art]

As a conventional inkjet recording device, for example, FIG.
(There is something in particular to indicate.)

This inkjet recording apparatus includes an ink jet nozzle 1 formed in a slit shape, an electrically insulating upper plate 2ae and a lower plate 2b forming the ink jet nozzle 1, and a predetermined position perpendicular to the recording paper 5 inside the upper plate 2&. A plurality of thin wire electrodes 3 made of phosphor bronze arranged at intervals, a ground conductor 4 disposed facing the ink jet nozzle 1, and a recording paper 5 that moves vertically along the ground conductor 4; It is comprised of a power source 6 for applying a high voltage to a selected one of the electrodes 3, and a switch 7 for selecting the high voltage of the power source 6 to the electrode 3.

In the above configuration, the operation will be explained. Ink stored in the ink holding container (not shown in the drawings) is supplied to the ink chamber 8 formed by the upper plate 2a and the lower plate 2b. When a voltage of 1 to 4 KV is applied to the electrode 3 connected to the high-voltage power source 6 in a switch corresponding to the recording signal, the electrode 3 to which the high voltage is applied and the ejection port 1 are connected to each other. A potential sufficient to exert electrostatic attraction on the ink is generated between the ink and the ground conductor 4, forming ink droplets, which are eventually separated from the ink chamber 8 and attached to the recording paper 5. By performing this operation continuously, any desired recording surface can be formed on the recording paper 5.

FIG. 2 has a structure similar to that of FIG. 1(A)@, but the only difference is that the tip of the electrode 3 does not protrude toward the ink ejection port 1.

In both FIG. 1 (4) (B) and FIG. 2, the structure of the recording head section is simple, and the tip of the electrode 3 can be placed close to the meniscus formed by the ink jet nozzle l, so the ink jet response It had the advantage of high speed.

However, since conventional inkjet recording devices use wires with a small diameter for electrodes, the electric field within the ink due to voltage application becomes uneven, causing variations in ink particle size and making it difficult to record accurately. Not done. Furthermore, since the contact area between the electrode and the ink was small, charge injection efficiency was poor and high voltage application was required.

[Object and structure of the invention]

The present invention has been made in view of the above.

To provide an ink jet recording device in which a recording electrode surface having a sufficiently larger area than the ink jet orifice faces the ink jet orifice in order to improve charge injection efficiency and form ink droplets of uniform particle size. .

〔Example〕

An inkjet recording apparatus according to the present invention will be explained in detail below.

The third factor shows an embodiment of the present invention, and includes an ink tank 11 that stores ink to be supplied to the recording head A, and a constant amount of ink in the ink tank 11 that is always supplied to the recording head A. A pump 12, a housing 13 that holds the supplied ink and forms an ink circulation gap, and a recording paper 17.
A slot-shaped ink ejection port 14 that ejects ink droplets, an insulating pedestal 15 located inside the housing 13 and forming an ink circulation gap, and an ink ejection direction and a vertical plane with the ejection port 14 interposed therebetween. Plate-shaped recording electrodes 16 fixed to the top surface of the gantry and arranged at predetermined intervals in the longitudinal direction of the gantry;
A counter electrode 18 is provided on the back surface of the recording paper 17 to give electrostatic acceleration to the ink droplets formed on the front surface, and a counter electrode 18 is connected between the recording electrode 16 and the counter electrode 18 to form ink droplets according to recorded information. A high voltage drive circuit 19 that applies a pulse voltage to
The recording electrode 16 and the counter electrode 1 are connected in series with this high voltage drive circuit 19 to apply electrostatic acceleration to the ink droplets.
and a high-voltage power supply 20 that applies an electric field between 8 and 8.

FIGS. 4(6) and 4(11) are perspective views showing in detail the housing 13 of the recording head and the recording electrodes 16 disposed inside.

FIG. 4 shows a stand 15 which is an insulating rectangular parallelepiped and occupies a volume around which an ink circulation gap is formed, and L-shaped plate electrodes 16 fixed to the top and front surfaces of the stand 15 at predetermined intervals in the longitudinal direction. It is configured. FIG. 4(b) is a perspective view of the pedestal 15 and the recording electrode 16 arranged inside the casing 13. The housing 13 has a space in which ink can be circulated between it and the pedestal 15, and has a slit 1 of a predetermined width on the surface facing the recording paper.
4 is engraved, and the plate-shaped recording electrode 16 is engraved with a slit 14.
It is located at the rear and perpendicular to the direction of ejection.

In the above configuration, ink filled in the ink tank 11 to a certain level is supplied to the recording head A by the pump 12. The supplied ink circulates around the outer peripheral surface of the pedestal 15 and is filled between the recording electrode 16 and the ink jetting port 14. A high voltage pulse aoo is applied to the recording electrode 16 according to the recorded information.
When v is applied, charge is injected into the ink and concentrated near the ink ejection port 14, and an ink droplet is ejected by electrostatic force. The ejected ink droplets are accelerated and attached to the recording paper 17 by an electrostatic field caused by a high voltage of 2 KV applied between the recording electrode 16 and the counter electrode 18.

FIG. 5 (8 to q describes the ink jetting mechanism in more detail. When a high voltage pulse of aoov is applied to the recording electrode 16 from the high voltage drive circuit 19 according to the recording information, the recording electrode 1
A positive charge is injected into the ink in contact with 6. Particularly, charges are injected efficiently in the vertical surface portion of the tip of the recording electrode surface 16a facing the counter electrode (FIG. 5(A)). When positive charge is injected, the recording electrode 16 and the opposing electrode 4
Due to the electrostatic field between 8 and 8, the positively charged ink is concentrated near the ink ejection port 14 and is attracted to the counter electrode 18 while being repelled by the electrode 16m (FIG. 5(B)). Due to this repulsion and suction force, ink droplets 21 are formed and fly to the recording paper 17 (FIG. 5(a)).

In this embodiment, the width of the recording electrode is made sufficiently larger than the width of the ink ejection port 14, so that the charge injected into the ink can be uniformly applied to each ink droplet.

FIG. 6 shows another embodiment of the recording head section of the present invention,
The same parts as in FIG. 3 are indicated by the same reference numerals, so redundant explanation will be omitted. A mesh-like recording electrode 22 is fixed to the inner wall of the slit-forming surface of the housing 13, and one end is connected to a high-voltage drive circuit 19 and a high-voltage power source 2° as shown in FIG.

In the above configuration, when a high voltage pulse is applied as explained in FIG. 2, an electric charge is injected into the ink flowing through the mesh L, which is attracted to the vicinity of the ink ejection port 14 and ejected as ink droplets.

In this embodiment, since the recording electrode 22 has a mesh shape, the recording electrode 22 has a large contact area with the ink and can move close to the ink jetting port 14 so as to be easily subjected to an electrostatic accelerating electric field.

〔Effect of the invention〕

According to the ink jet recording apparatus of the present invention as described above, the recording electrode surface having a sufficiently larger area than the ink jet orifice faces the ink jet orifice.

Ink droplets with a uniform particle size can be formed by improving charge injection efficiency.

[Brief explanation of drawings]

FIG. 1 (A) @ is a configuration diagram of a conventional inkjet recording apparatus, FIG. 2 is a sectional view of another conventional recording head section, FIG. 3 is an explanatory diagram showing an embodiment of the present invention, and FIG. 4 (5) (b)
FIG. 6 is a perspective view of the recording section of the present invention, and an explanatory view showing the step of forming droplets in the fifth box. FIG. 6 is a sectional view showing another embodiment of a recording head having a mesh-like electrode portion. Explanation of symbols 1...S/R spout, 2m...Top plate, 2b...
Lower plate, 3... Wire-shaped electrode, 4... Ground conductor, 5
...recording paper, 6...power supply, 7...switch, 8.
... Ink chamber, 11 ... Ink tank, 12 ... Pump, 13 ... Housing, 14 ... Ink ejection port (slit), 15 ... Mount, 16 ... Recording electrode, 17
...Recording paper, 18...Counter electrode. 19... High voltage drive circuit, 20... High voltage power supply. 21... Ink droplet, 22... Me, spider-shaped recording electrode. Figure 5 (A) 1 (B) 5 CC)

Claims (1)

[Claims] In an inkjet recording device including a recording electrode that applies a voltage according to recording information to ink in an ink chamber having an ink discharge nozzle, the recording electrode faces the nozzle and is arranged in a plane perpendicular to the flying direction of ink droplets. An inkjet recording device characterized by having a flat electrode surface located at .