JP2783224B2 - Ink jet head 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 ink-jet head device, and more particularly to an ink-jet head device for performing recording by adhering ink ejected by the action of an electric field to recording paper.

[0002]

2. Description of the Related Art A conventional example of this kind is disclosed in Japanese Patent Application Laid-Open No. 2-67143.
No. 6,086,045. The one described in this publication is shown in FIG.
As shown in (a), the ink jet head has a plurality of ink ejection ports 66, and inside each of these ejection ports 66, a recording electrode 52 for applying an electrostatic force to the liquid ink to eject the ink is provided. In addition, dummy electrodes 53 are arranged on both sides of the plurality of injection ports 66 in the longitudinal direction of the head body in which the plurality of injection ports 66 are arranged in parallel. When a voltage is applied to the predetermined recording electrode 52, an electric field is generated between the recording electrode 52 and the grounded counter electrode 55, and the ink droplet 6
2 is ejected and flies toward the counter electrode 55. Specifically, it utilizes electrostatic force acting on a conductive or dielectric liquid ink in an electric field. An electric field generated between the recording electrode 52 and the counter electrode 55 causes the liquid ink to be electrostatically induced or polarized. It is accumulated on the recording electrode 52 by the action. As a result, the liquid ink is pulled in the direction of the counter electrode 55 by the Coulomb force acting on the stored liquid ink. Then, when the Coulomb force finally overcomes the surface tension of the liquid ink, the ink droplet 62 is ejected. The flying ink droplets 62 adhere to the recording paper before reaching the counter electrode 55, and printing is performed.

At this time, the outermost recording electrode 52 of the juxtaposed recording electrodes and the inner recording electrode 52 adjacent thereto are arranged.
When ink is ejected from the same time, the electric field formed by the outer recording electrode 52 varies, causing an error in the ink flying direction. Therefore, as shown in FIG. Is applied so that the electric field (lines of electric force 65) formed by the recording electrodes becomes uniform except for the electric fields at both ends formed by the dummy electrodes 53,
This ensures the straightness of the ejection direction of the ink droplet 62 and improves the ejection direction accuracy at both ends of the inkjet head.

[0004]

However, in the conventional example described in the above-mentioned publication, when a plurality of dots arranged continuously are recorded, that is, an ejection voltage is simultaneously applied to a plurality of adjacent recording electrodes. In these cases, if these recording electrodes are not adjacent to the dummy electrodes, the electric field formed by the recording electrodes at both ends causes a variation in the forming direction as in the case where there is no dummy electrode in the above-described conventional example, and the ink is ejected. There is a disadvantage that the direction and the flying amount are uneven.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet head device which solves the above-mentioned disadvantages of the prior art, and in particular, which improves the accuracy of the flight direction of ink irrespective of a recording electrode for energizing ink ejection. And its purpose.

[0006]

According to a first aspect of the present invention, there is provided an ink chamber for storing ink containing charged toner particles, and a discharge opening communicating the ink chamber with the outside. Part, a grounded counter electrode facing the discharge opening via recording paper, a plurality of recording electrodes arranged in parallel at a predetermined interval in the longitudinal direction of the discharge opening, and a plurality of recording electrodes. A dummy electrode arranged on the outside, a migration electrode provided in the ink chamber for electrophoresis of toner particles at a discharge opening, and a voltage for setting a predetermined voltage to each of the plurality of recording electrodes, the dummy electrode, and the migration electrode. A setting unit. When the voltage setting unit sets the ejection voltage to two or more adjacent recording electrodes at the same time among the plurality of recording electrodes, the voltage setting unit simultaneously sets the ejection voltage to the adjacent recording electrodes or dummy electrodes on both sides of the two or more recording electrodes. A configuration is provided in which an auxiliary voltage setting function for setting an auxiliary voltage is provided.

[0007] In the present invention, the voltage applied to each recording electrode is controlled by the voltage setting unit so that the ejection voltage, the auxiliary voltage, and the standby voltage (0
[V]). When it is determined by the host device that ink is to be ejected from two or more recording electrodes at the same time, the voltage setting unit 15 determines whether or not there is an adjacent recording electrode to which ink should be ejected at the same time ( Step S1). If there is an adjacent recording electrode to be used for ink ejection, the auxiliary voltage 14 (Vsp) is applied to the adjacent recording electrode 2 or dummy electrode 3R (3L) on both sides of the two or more adjacent recording electrodes.
[V)] (step S2). At about the same time, an ejection voltage 13 (Vej [V]) is applied to all the recording electrodes where ink ejection is to be performed (step S).
3). On the other hand, when there is no adjacent recording electrode to perform ink ejection, the ejection voltage 13 is applied to a predetermined recording electrode without applying the auxiliary voltage 14 (Step S).
3).

[0010] The second aspect of the present invention adopts a configuration in which the dummy electrode is formed on the same surface as the recording electrode. In the third aspect of the present invention, the setting of the voltage setting section is assisted. The voltage is set such that the toner particles are not discharged from the discharge opening. With these, the above-mentioned object is to be achieved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG.

The ink jet head device shown in FIGS. 1 and 2 has an ink chamber 1 for storing an ink 7 containing charged toner particles, a discharge opening 8 for communicating the ink chamber 1 with the outside, A counter electrode 5 that is grounded and faces the discharge opening 8 via the recording paper 6, and a plurality of recording electrodes 2, 2,... Arranged side by side at predetermined intervals in the longitudinal direction of the discharge opening 8. A plurality of recording electrodes 2, 2, ...
, Dummy electrodes 3R, 3L, a plurality of recording electrodes 2, 2,..., Dummy electrodes 3R, 3L, which are provided in the ink chamber 1 and which electrophores toner particles into the ejection openings 8. And a voltage setting unit 15 for setting each predetermined voltage to the migration electrode 4. Among them, the voltage setting unit 15 includes a plurality of recording electrodes 2, 2,.
Of two or more adjacent recording electrodes at the same time.
Is set, an auxiliary voltage setting function is provided for simultaneously setting the auxiliary voltage 14 to the recording electrode 2 or the dummy electrode 3R (3L) adjacent to both sides of the two or more recording electrodes.

More specifically, in this embodiment, the ink chamber 1 is provided between a base 1a, which is a dielectric, and a cover member 1b of the same dielectric, which is provided on the base 1a. Is provided. In the cover member 1b,
An ink supply port 10 and an ink discharge port 11 connected to an external ink tank via a tube conduit are provided. A pump is provided in the tube line connecting to the ink tank, and the ink 7 in the ink chamber 1 is 1 cm.
It is forcibly circulated in a state where a negative pressure of about H ₂ O is applied.

A plurality of recording electrodes 2, 2,... And dummy electrodes 3R, 3L are formed in parallel on the same surface on the base 1a. The recording electrodes 2, 2,... And the dummy electrodes 3
R and 3L are formed by forming a conductive material such as Cu and Ni into a band shape by electroforming, and the width thereof is set to about 50 μm. The arrangement width between the adjacent recording electrodes 2, 2,... Or the dummy electrodes 3R, 3L is arranged at a pitch of 300 dpi, that is, at an interval of 85 [μm].

The electrophoretic electrode 4 is formed of a conductive material in a flat plate shape, and is fixed to the inner wall of the ink chamber 1 on the side opposite to the ink ejection direction.

The counter electrode 5 is disposed on an extension of the recording electrodes 2, 2,... And is grounded via a resistor. A recording paper 6 is arranged between the counter electrode 5 and the discharge opening 8 so as to be in contact with the counter electrode 5. This recording paper 6
Are transported in the vertical direction in FIG.

The ink 7 is a dispersion of fine particles of a thermoplastic resin colored in a petroleum organic solvent (isoparaffin) together with a charge control agent, a so-called toner. The toner is positively charged to a positive polarity by the zeta potential. Things.

The discharge opening 8 is formed between the base 1a and the cover member 1.
It is formed in the shape of a slit as a gap between b. The discharge opening 8 is divided into a plurality of meniscus forming parts by a plurality of flow path walls 9, 9,.
Are arranged at positions corresponding to the recording electrodes 2, 2,... Or the dummy electrodes 3R, 3L, respectively. The plurality of flow path walls 9 only divide the discharge opening 8, and all the meniscus forming portions communicate with each other inside the ink chamber 1.

The voltage setting section 15 applies the ink 7 to the electrophoresis electrode 4.
A function of constantly applying a voltage of the same polarity as the toner particles inside,
A function of selectively applying a discharge voltage 13 (Vej [V]), an auxiliary voltage 14 (Vsp [V]) or a standby voltage 0 [V] to the recording electrode 2 based on predetermined conditions;
A function of selectively applying the auxiliary voltage 14 or the standby voltage 0 [V] to 3L based on a predetermined condition. The voltage applied to the migrating electrode 4 is applied to the ink droplet 1 through the ejection opening 8.
It is desirable to set as high a value as possible so as not to cause the ejection of No. 2. The ejection voltage 13 is a voltage having the same polarity as that of the toner particles in the ink 7, and is a voltage set so that ink is ejected from the ejection opening 8 by being applied to the recording electrode 2. On the other hand, the auxiliary voltage 14 is
Even if it is applied to the recording electrode 2 or the dummy electrodes 3R, 3L,
The value is set as high as possible so as not to cause the ejection of the ink droplet 12 from the ejection opening 8. Here, the predetermined condition for selecting the voltage to be applied to the recording electrode 2 or the dummy electrodes 3R and 3L will be described later.

Next, the overall operation of the present embodiment will be described with reference to FIGS.

When the entire apparatus is set to the operating state, the circulation of the ink 7 in the ink chamber 1 is started, and a plurality of ink meniscuses are formed between the flow path walls 9 of the discharge openings 8. When a predetermined voltage is applied to the migration electrode 4 from the voltage setting unit 15, the potential of the ink 7 is also set to the same potential as the migration electrode 4, and the toner particles in the ink 7 are discharged to the ejection opening 8. Perform electrophoresis and concentrate on the meniscus. Then, when the recording electrode 2 to perform ink ejection is determined,
The voltage setting unit 15 applies an ejection voltage 13 (V
ej [V]). Thereby, the recording electrode 2
The meniscus is drawn out from both sides of the flow path wall 9 arranged correspondingly in the ink ejection direction, and the toner particles further concentrate on the tip. Then, when the Coulomb force acting on the group of toner particles overcomes the surface tension of the ink 7, the ink droplet 12 is ejected from the position where the recording electrode 2 is disposed on an extension of the recording electrode 2. Most of the components of the ink droplet 12 are a group of toner particles, and this is accompanied by some ink liquid.

The ejected ink droplets 12 adhere to the recording paper 6, and only the toner particles in the ink droplets 12 remain on the surface of the recording paper 6. The toner particles adhering to the recording paper 6 are conveyed to a fixing unit and then heat-fixed, thereby performing recording. As described above, since the dots are formed with the toner particles in the ink 7 as a main component, bleeding or the like on the recording paper 6 which is inconvenient in the conventional ink jet system does not occur, and high printing quality comparable to that of the electrophotographic system is obtained. It can be carried out.

Next, the operation of the voltage setting unit 15 when ink is to be ejected from two or more recording electrodes 2 at the same time will be described in detail with reference to FIG.

When the host device determines that ink is to be simultaneously ejected from two or more recording electrodes, the voltage setting unit 1
Step 5 determines whether or not there is an adjacent one of the recording electrodes to be simultaneously ejected (step S1).
In the case where there is an adjacent recording electrode from which ink is to be ejected, the auxiliary voltage 14 (Vsp [Vsp [Vsp []) is applied to the adjacent recording electrode 2 or dummy electrode 3R (3L) on both sides of the adjacent two or more recording electrodes. V)] (Step S)
2). At about the same time, an ejection voltage 13 (Vej [V]) is applied to all the recording electrodes to be ejected (step S3). On the other hand, if there is no adjacent recording electrode to be used for ink ejection, the auxiliary voltage 14
The ejection voltage 13 is applied to a predetermined recording electrode without applying the voltage (step S3).

For example, in FIG. 3A, when ink is ejected from the four recording electrodes 2a, 2b, 2c, 2d, an auxiliary voltage 14 is applied to the dummy electrode 3R and the recording electrode 2e adjacent on both sides. Applied and the recording electrode 2
The ejection voltage 13 is applied to the terminals a, 2b, 2c, and 2d. As a result, not only the electric field formed by the recording electrode 2a (lines of electric force 16), but also the distribution of the electric field formed by the recording electrode 2d is substantially uniform with the distribution of the electric field formed by the recording electrodes 2b and 2c. Therefore, as shown in FIG. 3B, each of the recording electrodes 2a, 2a
The rectilinearity of the ink droplets 12 ejected from the positions b, 2c, and 2d can be secured.

The above operation and effect are the same when the ink droplets 12 are ejected from any adjacent recording electrodes 2, 2,..., And are ejected from the recording electrodes at both ends of the adjacent recording electrodes for ink ejection. Ink droplets 12 and ink droplets 12 ejected from the recording electrode between the ink droplets 12 can be prevented from varying in the amount and direction of the droplets.

In addition, in the present embodiment, since the dummy electrodes 3R, 3L are formed on the same surface as the plurality of recording electrodes 2, 2,.
R and 3L can be formed simultaneously by a method such as photolithography, and the manufacturing process can be simplified. Further, since the auxiliary voltage 13 is set to such a degree that ink is not ejected from the ejection opening 8, even if the dummy electrodes 3R and 3L are provided in the ink chamber 1, accidental ink discharge by the dummy electrodes 3R and 3L will occur. Discharge can be prevented.

Here, regardless of the present embodiment, when ink is ejected, the auxiliary voltage 14 may be applied to all the recording electrodes and dummy electrodes that do not eject ink. In this case, it is possible to effectively suppress variations in all ink ejection directions regardless of the combination of recording electrodes for performing ink ejection. Further, even when the ejection voltage 13 is applied to the single recording electrode 2, the ejection electrodes 2
Alternatively, the auxiliary voltage 14 may be applied to the dummy electrodes 3R and 3L. In this case, the directivity of the ink ejected from the single recording electrode 2 can be further improved.

[0027]

Since the present invention is constructed and functions as described above, according to this, when the voltage setting unit sets the discharge voltage to two or more adjacent recording electrodes at the same time among a plurality of recording electrodes, Since the auxiliary voltage is set to the recording electrodes or the dummy electrodes adjacent to both sides of the two or more recording electrodes at the same time, the distribution of the formed electric field is not dependent on the recording electrodes to be ejected when recording any continuous dot. Can be provided, and a highly accurate ink jet head device can be provided, which is capable of suppressing variations in the droplet volume and directionality at the time of ink ejection and performing high-precision printing.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a cross section of a part of a head main body according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a configuration of an electric system of the embodiment shown in FIG.

3A and 3B are explanatory views showing the state of ejection of ink droplets in the embodiment shown in FIGS. 1 and 2. FIG. 3A shows the voltage applied to each recording electrode and the distance between the recording electrode and the counter electrode. FIG. 3B shows the state of the lines of electric force to be formed, and FIG.

FIG. 4 is a flowchart illustrating an operation of a voltage setting unit in a case where ink droplets are simultaneously ejected from two or more recording electrodes in the embodiment illustrated in FIGS. 1 and 2;

5A and 5B are configuration diagrams showing a conventional example, in which FIG. 5A shows a state of ejection of ink droplets, and FIG. 5B shows an electric force formed between a recording electrode or a dummy electrode and a counter electrode. The state of the line is shown.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink chamber 2 Recording electrode 3 Dummy electrode 4 Migration electrode 5 Counter electrode 6 Recording paper 7 Ink 8 Discharge opening 13 Discharge voltage 14 Auxiliary voltage

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hitoshi Minemoto 5-7-1 Shiba, Minato-ku, Tokyo Inside NEC Corporation (72) Inventor Yoshihiro Hagiwara 5-7-1 Shiba, Minato-ku, Tokyo Japan (56) References JP-A-9-1824 (JP, A) JP-A 8-90825 (JP, A) (58) Fields studied (Int. Cl. ⁶ , DB name) B41J 2 / 06 B41J 2/385

Claims (3)

(57) [Claims] 1. An ink chamber for storing ink containing charged toner particles, a discharge opening communicating between the ink chamber and the outside, and a grounded opposition opposed to the discharge opening via recording paper. An electrode, a plurality of recording electrodes arranged side by side at predetermined intervals in a longitudinal direction of the discharge opening, a dummy electrode disposed outside the plurality of recording electrodes, and the toner particles provided in the ink chamber. An ink-jet head device comprising: an electrophoresis electrode for causing electrophoresis in the discharge opening; and a voltage setting unit for setting a predetermined voltage to each of the plurality of recording electrodes, the dummy electrode, and the electrophoresis electrode. When the setting unit sets the ejection voltage to two or more recording electrodes adjacent to each other simultaneously among the plurality of recording electrodes, the recording adjacent to both sides of the two or more recording electrodes is performed. Inkjet head apparatus characterized in that an auxiliary voltage setting function at the same time setting the auxiliary voltage to Kyokumatawa dummy electrode. 2. An ink jet head device according to claim 1, wherein said dummy electrode is formed on the same surface as said recording electrode. 3. The ink jet head device according to claim 1, wherein the auxiliary voltage set by the voltage setting unit is set to such an extent that the toner particles are not discharged from a discharge opening. .