JP2885715B2 - Head drive control method of electrostatic ink jet 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 ink jet recording apparatus, and more particularly to a head drive control method for an electrostatic ink jet recording apparatus for controlling color material particles in a pigment ink by an electrophoretic phenomenon.

[0002]

2. Description of the Related Art An example of an electrostatic ink jet recording apparatus utilizing an electrophoretic phenomenon will be described with reference to FIGS. FIG. 6 is a schematic diagram for explaining a head driving method of a conventional electrostatic ink jet recording apparatus, FIG. 7 is a diagram showing voltage waveforms applied to an electrophoretic electrode and an ejection electrode, and FIG. 9) is a distribution diagram of color material particles in the vicinity, FIG. 9 is a distribution diagram of color material particles in the vicinity of the ejection electrode (C) described later, and FIG. 10 is a distribution diagram of color material particles in the vicinity of the ejection electrode (B) described later.

Next, a conventional head driving method will be described. The voltage of the constant voltage Vep shown in FIG. 7 is applied to the electrophoresis electrode 103 shown in FIG.
When an electric field is applied to the ink chamber 101 where 0 is filled,
The coloring material particles 317 in the pigment-based ink 210 move to the ink ejection port 102. The ink ejection port 10 shown in FIG.
When the color material particles 317 move to 2, the meniscus 316 shown in FIG. 8 is generated.

In this state, the control unit 114 shown in FIG.
Is a discharge electrode (A) 105 for discharging the color material particles 317 in accordance with print data and a print control signal input from a computer or the like via the input interface 113.
And discharge electrodes (B) 11 adjacent to the discharge electrodes that do not perform discharge
6 and a voltage signal to be further applied to the outer discharge electrode (C) 117, and sends this voltage determination signal to the discharge electrode voltage controller 115. And the discharge voltage control unit 11
5 detects the voltage determination signal from the control unit 114,
As shown in FIG. 7, a voltage V is applied to the ejection electrode (A) 105.
A voltage of p and a time Tp are applied, and a voltage of Vc and a time Tp are applied to the discharge electrode (C) 117. Note that the discharge electrode (B) 116 is in a non-ground floating state for a time Tp without applying a voltage.

As a result, while the voltage Vp is applied to the discharge electrode (A) 105 for discharging the color material particles 317, the color material particles 317 move and concentrate at the tip thereof. A uniform meniscus 316 is formed as shown in FIG. 7, in which the toner particles are held at a high concentration. Also,
The discharge electrode (C) 117 that does not perform discharge also applies the voltage Vc.
While the color is applied, the coloring material particles 317 move and concentrate at the tip, so that a uniform meniscus 316 as shown in FIG. 9 is formed. However, the applied voltages Vp and Vc are
Since Vp> Vc is set, the amount of the moving color material particles 317 is smaller and the density thereof is lower than the tip of the discharge electrode (A) 105.

Since the discharge electrode (B) 116 is in a non-ground floating state, the voltage V
From the ejection electrode (A) 105 applied with p toward the ejection electrode (C) 117 applied with the voltage Vc, the balance is just brought into equilibrium under the influence of the electric field, and the voltage Vz is induced. A voltage V is applied to the discharge electrode (B).
While z is induced, the coloring material particles 317 move and concentrate at the tip, so that a uniform meniscus 316 is formed as shown in FIG. 10, but the voltage of each ejection electrode is Vp
>Vz> Vc, the amount of the moving color material particles 317 is smaller in the ejection electrode (B) 116 and the ejection electrode (C) 117 than in the tip of the ejection electrode (A) 105, and the density Will also be diluted.

[0007] The discharge electrode (B) 116 is just balanced when it is affected by the electric field to be in an equilibrium state, so that the color material particles 317 are moved from the discharge electrode (A) to the discharge electrode (B) 1.
The phenomenon of moving toward 16 can be prevented.
Further, since the voltage Vp applied to the discharge electrode (A) is set to a voltage high enough to discharge the color material particles 317, only the discharge voltage (A) is applied to the pigment-based ink 210 by electrostatic force. Overcoming the surface tension and the viscous force, the flying particle group 111 is ejected at the timing synchronized with the time Tp and caused to fly to the recording medium 104, and such an operation is repeatedly performed to form an image on the recording medium 104. .

[0008]

The head drive control method of the conventional electrostatic ink jet recording apparatus is as described above.
A voltage Vep is applied to the electrophoretic electrode 103 to apply an electric field to the ink chamber 101 filled with the pigment-based ink 210 to move the color material particles 317 in the pigment-based ink 210 to the ink discharge port 102. Meniscus 316 formed at the tip of discharge electrode (A) 105 for performing discharge
And the discharge electrode (A) 105 itself always generates a potential difference, and when no discharge is performed, the maximum Vep
Of the potential difference.

Therefore, when the voltage Vep is set relatively high, the potential difference between the voltage Vep and the discharge electrode (A) 10
5 itself, an insulating film (not shown) coating the periphery thereof, and the like may cause electrostatic breakdown. In addition, even when the normal voltage Vep is not so high, if the frequency of use is high, the discharge electrode (A) 105 may be fatigued or consumed,
The life of the recording head is shortened.

As another problem, when the wiring length between the discharge electrode voltage control section 115 and the discharge electrode (A) shown in FIG. 6 is long, the discharge voltage Vp applied to the discharge electrode (A) 105 is a resistance component of the wiring. As shown in FIG. 11, the rising characteristics of the color material particles 317 ejected at the time of ejection are not applied because a sufficient voltage is not applied to the ejection electrode (A). And the dot diameter of the flying particle group shown in FIG. 6 becomes unduly small, and there is a problem that the recording quality deteriorates.

Further, in the head driving method of the electrostatic ink jet recording apparatus described above as the prior art, when discharging from the discharge electrode (A) 105, it is necessary to drive five discharge electrodes as one set. In one printing cycle T, there is a problem that printing cannot be performed by discharging the color material particles 317 from the discharge electrode (B) 116 and the discharge electrode (C) 117. The present invention has been made to solve such a problem.

[0012]

According to the head drive control method of the electrostatic ink jet recording apparatus according to the present invention, a predetermined voltage is applied to an electrophoretic electrode, and coloring material particles in the ink are applied to an ink discharge port by an electrophoretic phenomenon. In a head drive control method of an electrostatic ink jet recording apparatus that performs recording by flying the color material particles by applying a discharge voltage to any of a plurality of discharge electrodes, A bias voltage is applied to the electrodes, and these ejection electrodes
At the end of these discharge electrodes during non-discharge
It is characterized by comprising means for reducing the potential difference from the scas .

When the head is driven, a bias voltage is applied to all the ejection electrodes in advance , and these ejection electrodes and the
Means for reducing the potential difference from the meniscus formed at the tip of these discharge electrodes, means for setting the discharge electrodes on both sides of any discharge electrode for discharging color material particles to a non-ground floating state, A means for applying a voltage to such an extent that the discharge of the color material particles does not occur to the discharge electrodes outside of the discharge electrodes on both sides, and when flying the color material particles, applying any voltage to the discharge electrode for discharging the color material particles. Means for applying a discharge voltage and inducing a voltage to such an extent that discharge of the color material particles does not occur on both adjacent discharge electrodes in the non-ground floating state.

Further, in a head drive control system of an electrostatic ink jet recording apparatus having a recording head having N discharge electrodes, all N discharge electrodes discharge color material particles in one printing cycle T. 3. The head drive control according to claim 2, wherein T / N
Is performed N times in a time-sharing manner.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing the outline of the configuration of an electrostatic ink jet recording apparatus for explaining a head drive control system according to a first embodiment of the present invention, and FIG. 2 is a schematic view showing an ejection electrode (A) and an ejection electrode in the first embodiment. FIG. 3B is a waveform diagram showing respective applied voltages to the ejection electrode (C) and FIG. 3 is a diagram showing rising characteristics of the ejection electrode (A) in the first embodiment when a voltage is applied, and FIG. FIG. 9A is a distribution diagram of color material particles in the vicinity, FIG. 9 is a distribution diagram of color material particles in the vicinity of the discharge electrode (C),
FIG. 10 is a distribution diagram of the coloring material particles near the ejection electrode (B).

Next, the operation will be described. When a constant voltage Vep shown in FIG. 2 is applied to the electrophoretic electrode 103 shown in FIG. 1 and an electric field is applied to the ink chamber 101 filled with the pigment ink 210 shown in FIG. When the material particles 317 move to the ink ejection port by an electrophoretic phenomenon and the color material particles move to the ink ejection port 102, a meniscus 316 is generated. On the other hand, the control unit 114 shown in FIG.
Is a discharge electrode (A) 105 for discharging the color material particles 317 in accordance with print data and a print control signal input from a computer or the like via an input interface, and a discharge which is located on both sides thereof and does not perform discharge. A voltage signal to be applied to the electrode (B) and the discharge electrode (C) outside the electrode (B) is determined, and this voltage signal is sent to the discharge electrode voltage control unit 115.

The discharge electrode voltage control unit 115 includes a control unit 11
When the voltage signal from the discharge electrode 4 is detected, as shown in FIG.
Is applied. The bias voltage Vb applied before the ejection is set to a voltage high enough not to cause the ejection, and the ejection voltage Vp for performing the ejection is Vp>
Vb. A voltage V is applied to the ejection electrode (C) 117.
c, a voltage at time T is applied, and no voltage is applied to the discharge electrode (B) 116, so that the discharge electrode (B) 116 is in a non-ground floating state. Thereafter, when discharging the color material particles 317 from the discharge electrode (A) based on the print data, the discharge electrode voltage control unit 115 applies a discharge voltage of the voltage Vp and the time Tp to the discharge electrode (A) 105. I do.

In the discharge electrode (A) 105 for discharging the color material particles 317, the color material particles 317 move and concentrate at the tip while the voltage Vp is applied. A uniform meniscus 316 is formed as shown in FIG. 7, in which the toner particles are held at a high concentration. Similarly, the discharge electrode (C) 117 which does not perform discharge also applies the voltage Vc.
While is applied, the coloring material particles 317 move and concentrate at the tip, so that a uniform meniscus 316 as shown in FIG. 9 is formed at the tip. However, the voltage Vp applied to the ejection electrode (A) 105 and the voltage Vc applied to the ejection electrode (C) 117 have a relationship of Vp> Vc, and the subsequent ejection of the color material particles 317 is performed by the ejection electrode (A). ) It occurs only from 105 and does not discharge from the discharge electrode (C).

Since the discharge electrode (B) 116 is in a non-ground floating state, the voltage V
When affected by the electric field from the ejection electrode (A) 105 to which p is applied toward the ejection electrode (C) 117 to which the voltage Vc is applied, the voltage is just balanced and equilibrium, and the voltage Vz is induced. While the voltage Vz is being induced, the coloring material particles 317 move and concentrate at the tip of the discharge electrode (B) 116, so that a uniform meniscus 316 as shown in FIG. 10 is formed at the tip. You. However, each voltage has a relationship of Vp>Vz> Vc, and the voltage Vz is lower than the voltage Vp at which the discharge occurs, and therefore, the discharge electrode (C) 1
The amount of movement of the color material particles 317 moving to the front end of the discharge electrode 17 is smaller than that of the discharge electrode (A) 105 and the density thereof is low.
7 does not occur.

Further, since the discharge electrode (B) 116 is in a non-ground floating state as described above, the head drive control for applying a voltage to only one discharge electrode becomes a balanced state just after being balanced by the influence of the electric field. The phenomenon in which the color material particles 317 move from the ejection electrode (A) 105 toward the ejection electrode (B) 116, which is a problem in the method, can be prevented, and good recording quality can be secured.

In the first embodiment, since the bias voltage Vb is applied to the ejection electrode before the ejection is performed as described above, the constant voltage Vep is applied to the ejection electrode (A) 105 to form the ejection electrode. The potential difference generated between the meniscus 316 and the ejection electrode (A) 105 becomes Vep-Vb at the maximum, and the potential difference can be reduced, and the ejection electrode (A) 105 itself and the insulating film ( (Not shown) can be prevented from being electrostatically damaged, fatigue and wear of the head can be suppressed more lightly, and the life of the head can be extended.

Further, as in the first embodiment, the bias voltage V
With the configuration in which b is applied, when the ejection voltage Vp is applied during ejection, the rising characteristics can be improved as shown in FIG. That is, as shown by the solid line in FIG. 3, the rise time tb when the voltage Vp is applied from the state where the bias voltage Vb is applied is:
Since the desired ejection voltage Vp can be obtained in a shorter time than the rising time ta when the voltage Vp is applied from the point of time of the conventional voltage 0 V indicated by the one-dot chain line, this causes a problem in the conventional head drive control method. Flying particle group 1 caused by dull rising characteristics when wiring length is long
It is possible to solve the problem that the dot diameter of No. 11 is unduly reduced and the recording quality is degraded.

In the above description of the first embodiment, the head drive control method of the electrostatic ink jet recording apparatus for setting the discharge electrodes (B) 116 on both sides to the non-ground floating state is described. The same applies to an apparatus that applies a voltage to only one of the ejection electrodes for performing
It goes without saying that a similar effect can be obtained.

Embodiment 2 FIG. FIG. 4 is a perspective view showing a configuration of an ink jet recording apparatus utilizing an electrophoresis phenomenon, and FIG. 5 is a waveform diagram of a voltage applied to an ejection electrode according to the second embodiment. As shown in FIG. 4, an electrostatic ink jet recording apparatus having a plurality of ejection electrodes includes an ink chamber 101 filled with a pigment-based ink 210, and an ink chamber 101 filled with the pigment-based ink 210.
An electrophoretic electrode 103 for concentrating the coloring material particles 317 in the ink ejection port 102 by an electrophoresis phenomenon, and a plurality of electrophoretic electrodes 103 for ejecting the coloring material particles 317 concentrated on the ink ejection port 102 and causing them to fly onto the recording medium 104. (Eight electrodes 220 to 227 in the embodiment shown in FIG. 4), and a counter electrode 109 disposed on the back surface of the recording medium 104 to face these discharge electrodes.

The ink ejection port 102 is provided for each ejection electrode 2
05, the meniscus 3 of the pigment-based ink 210 convex at the tip
Each discharge electrode 2 is formed by the flow path wall 208 so that
It is partitioned every 20 to 227. The ink chamber 101
An ink tank is connected to the ink supply port 206 and the ink discharge port 207 by a tube (not shown), and a back pressure is applied to the ink in the ink chamber 101 and the pigment ink 210 in the ink chamber 101 is supplied to the ink tank. It is configured to forcibly circulate.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the print cycle T is time-divided into eight, and one-eighth of the ejection time is assigned to each ejection electrode. That is, 1 / 8T is the ejection electrode 1, 2/8.
T is the discharge electrode 2 and the discharge time 8 of the discharge electrode 8
/ 8T is assigned to the print cycle T. Here, each of the eight divided ejection times 1 / 8T to 8 / 8T is set to a time that can sufficiently discharge the color material particles. Then, during the time indicated by α in FIG. 5 from when the power of the printing apparatus is turned on to immediately before the start of ejection, the above-described bias voltage Vb is applied to all the ejection electrodes.

In part A1 of FIG. 5, the discharge electrode voltage control section 115 applies the bias voltage Vb to the discharge electrode 1 for the time Tb, and sets the discharge electrode 2 to the non-ground floating state (accordingly, as described above, Vz is induced: A2 part in the figure), and a voltage Vc is applied to the ejection electrode 3 so that the color material particles 317 are not ejected for 1/8 T time (A3 part in the figure).
The other electrodes continue to apply the bias voltage Vb as it is (A4 part in the figure). In addition, the discharge electrode 1 for performing discharge includes:
After the elapse of the above-described Tb time, the ejection voltage Vp is changed to (１ ／ T−T).
b) Apply for a time.

At the next timing 2 / 8T, a bias voltage Vb is applied to the discharge electrode 2 for Tb at B2 in the figure, and the discharge electrode 1 (B1 in the figure) and the discharge electrode 3 (B3 in the figure). Is in a non-ground floating state, a voltage Vc that does not cause ejection is applied to the ejection electrode 4 for ２T time (part B4 in the figure), and the bias electrode Vb is applied to the other electrodes.
Is applied. In addition, the above-described T
After the elapse of b time, the ejection voltage Vp is applied for (２ Tb) time. Similarly, at the next timing 3 / 8T, the bias voltage Vb is applied to the ejection electrode 3 for Tb at C3 in the figure, and the ejection electrode 2 (C2 section in the figure) and the ejection electrode 3 (C4 section in the figure) are connected. In a non-ground floating state, a voltage Vc that does not cause ejection is applied to the ejection electrode 1 (portion C1 in the drawing) and the ejection electrode 5 (portion C5 in the drawing) for ／ T, and a bias electrode Vb is applied to the other electrodes. Apply. The ejection voltage Vp is applied to the ejection electrode 3 that performs ejection for (3 / 8T-Tb) after the elapse of the above-described Tb.

As described above, the printing cycle T is divided into eight parts in a time-division manner, and the discharge electrode to be discharged is shifted at each timing. (Note that the waveform diagram of FIG. FIG. 9 is a waveform diagram when all of the ejection electrodes 1 to 8 are ejected. Needless to say, in actual recording, ejection is performed with the electrodes specified by the print data.) A head that drives five ejection electrodes as one set Even in the case where the drive control method is adopted, a configuration is possible in which the color material particles can be discharged from all the discharge electrodes in one printing cycle T based on the print data. In the second embodiment,
Although the description has been given of a head having eight ejection electrodes, it is needless to say that, in the case of a head having N ejection electrodes, the printing cycle T may be shifted in a time-division manner by N divisions.

[0030]

As described above, the head drive control method of the electrostatic ink jet recording apparatus according to the present invention employs a configuration in which a bias voltage is applied to the discharge electrode in advance and the potential difference between the discharge electrode and the meniscus formed at the tip of the discharge electrode. , It is possible to prevent the discharge electrode and the insulating film coated around the discharge electrode from causing electrostatic breakdown due to a large potential difference, thereby preventing the discharge electrode from being fatigued and consumed, and extending the life of the recording head. be able to. Further, since the bias voltage is applied to the ejection electrode in advance, the rising characteristics when the ejection voltage is applied can be improved, and the diameter of the flying particles caused by the dulling of the rising characteristics can be prevented from being reduced. There are effects such as the quality can be improved.

Further, in a head drive control system in which five electrodes in which both adjacent electrodes are in a non-ground floating state are driven as a set, the printing cycle is time-divided by the number of electrodes and voltage control of each electrode is performed once. In this case, the color material particles can be discharged from all the electrodes within one printing cycle.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an outline of a configuration of an electrostatic inkjet recording apparatus for describing a head drive control system according to a first embodiment of the present invention.

FIG. 2 is a waveform chart showing respective applied voltages to a discharge electrode (A), a discharge electrode (B), and a discharge electrode (C) in the first embodiment.

FIG. 3 is a diagram illustrating a rising characteristic when a voltage is applied to an ejection electrode (A) according to the first embodiment.

FIG. 4 is a perspective view illustrating a configuration of an ink jet recording apparatus using an electrophoresis phenomenon for explaining a second embodiment.

FIG. 5 is a waveform chart of a voltage applied to an ejection electrode performed in a second embodiment.

FIG. 6 is a schematic diagram for explaining a head driving method of a conventional electrostatic ink jet recording apparatus.

FIG. 7 is a diagram showing waveforms of voltages applied to an electrophoresis electrode and an ejection electrode.

FIG. 8 is a distribution diagram of color material particles in the vicinity of an ejection electrode (A).

FIG. 9 is a distribution diagram of color material particles in the vicinity of an ejection electrode (C).

FIG. 10 is a distribution diagram of color material particles near an ejection electrode (B).

FIG. 11 is a diagram showing a rising characteristic when a voltage is applied to an ejection electrode (A) in a conventional head driving method.

[Explanation of symbols]

 101 Ink chamber 102 Ink ejection port 103 Electrophoretic electrode 104 Recording medium 105 Discharge electrode (A) 109 Counter electrode 111 Flying particle group 113 Input interface 114 Control unit 115 Discharge electrode voltage control unit 116 Discharge electrode (B) 117 Discharge electrode (C) 205) discharge electrode 206 ink supply port 207 ink discharge port 208 flow path wall 210 pigment-based ink 220 discharge electrode 1 221 discharge electrode 2 222 discharge electrode 3 223 discharge electrode 4 224 discharge electrode 5 225 discharge electrode 6 226 discharge electrode 7 227 discharge Electrode 8 316 Meniscus 317 Colorant particles

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junichi Suetsugu 7546 Yasuda, Kashiwazaki-shi, Niigata Niigata Nippon Electric Co., Ltd. (72) Inventor Hitoshi Minemoto 7546 Yasuda, Kashiwazaki-shi, Niigata In-house (72) Inventor Kazuo Shima 7546 Yasuda, Niigata Prefecture Kashiwazaki-shi Niigata Nippon Electric Co., Ltd. Person Toru Yakushiji 7546 Yasuda, Kashiwazaki-shi, Niigata Niigata Nippon Electric Co., Ltd. (56) References JP-A-10-44426 (JP, A) JP-A 10-44433 (JP, A) JP-A 8- 258270 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) B41J 2/06

Claims (3)

(57) [Claims] 1. A method in which a predetermined voltage is applied to an electrophoretic electrode, color material particles in the ink are concentrated on an ink discharge port by an electrophoretic phenomenon, and the discharge voltage is applied to any one of a plurality of discharge electrodes. In a head drive control method of an electrostatic ink jet recording apparatus that performs recording by flying material particles, a bias voltage is applied to all ejection electrodes in advance when the head is driven , and these ejection electrodes and these ejection electrodes are used when ejection is not performed.
Means for reducing a potential difference from a meniscus formed at the tip of the head. 2. A bias voltage is applied to all ejection electrodes in advance when the head is driven, and a bias voltage is applied to these ejection electrodes when no ejection is performed.
Means for reducing the potential difference between the discharge electrode and the meniscus formed at the tip of the discharge electrode; discharging the color material particles on both sides of an arbitrary discharge electrode for discharging the color material particles when flying the color material particles The electrode is set to a non-ground floating state, a voltage is applied to the discharge electrodes outside the discharge electrodes on both sides so that discharge of the color material particles does not occur, and the discharge voltage is applied to any discharge electrode that discharges the color material particles. 2. The electrostatic device according to claim 1, further comprising means for applying a voltage to the adjacent discharge electrodes in the non-ground floating state to induce a voltage to such an extent that the color material particles are not discharged. A head drive control method for an ink jet recording apparatus. 3. A bias voltage is previously applied to all the ejection electrodes when the head is driven, and a bias voltage is applied to these ejection electrodes when no ejection is performed.
The potential difference between the discharge electrode and the meniscus formed at the tip of the discharge electrode is reduced, and when the color material particles are caused to fly, the discharge electrodes on both sides of any discharge electrode that discharges the color material particles In a non-ground floating state, applying a voltage to the discharge electrodes outside the discharge electrodes on both sides so that discharge of the color material particles does not occur, and applying the discharge voltage to any discharge electrode that discharges the color material particles. The control to apply is performed in a time division manner to T / N so that the color material particles can be discharged by all the N discharge electrodes in one printing cycle T by a recording head having N discharge electrodes. 3. A head drive control method for an electrostatic ink jet recording apparatus according to claim 2, wherein