JP2783206B2 - Inkjet printer 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 printer, and more particularly to an ink-jet printer in which color material particles in a pigment-based ink are controlled by an electrophoretic phenomenon.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view showing a head portion of a conventional ink jet printer utilizing an electrophoresis phenomenon. FIG. 4 is a partially enlarged view showing an example of the vicinity of the distal end of the discharge electrode in FIG. FIG. 5 is a waveform diagram showing a migration voltage and a discharge voltage applied to the electrophoresis electrode and the discharge electrode in FIG. Hereinafter, description will be made based on these drawings.

The head section 50 has an ink discharge port 52 and is filled with a pigment-based ink 54 in an ink chamber 56, and the color material particles 58 in the pigment-based ink 54 are concentrated on the ink discharge port 52 by an electrophoretic phenomenon. Electrophoretic electrode 60 for causing colorant particles 5 to concentrate on ink ejection port 52
Discharging electrode 64 for discharging the recording material 62 and discharging the recording material 62
It is provided with. A predetermined migration voltage Va is applied to the electrophoresis electrode 60, and a predetermined discharge voltage Vb is applied to the discharge electrode 64.

Next, the operation of the head unit 50 will be described. The head unit 50 utilizes an electrophoresis phenomenon in which, when an electric field is applied to the pigment-based ink 54 containing the charged coloring material particles 58, the coloring material particles 58 move in one direction under the electric field. That is, by applying a constant voltage V ₁ (high voltage) shown in FIG. 5 to the electrophoresis electrode 60 as the electrophoresis voltage Va, when an electric field is applied to the ink chamber 56 filled with the pigment ink 54, Since the color material particles 58 in the 54 move at a certain speed to the ink discharge port 52, the color material particles 58 are concentrated at the ink discharge port 52, and an ink meniscus 541 shown in FIG. 4 is formed. When the concentration of the color material particles 58 occurs, a pulse-like high voltage having a pulse width t ₂ and a voltage V ₂ shown in FIG. 5 is applied to the discharge electrode 64 as the discharge voltage Vb. Then, the color material particles 58 overcome the meniscus force, surface tension, viscous force, etc. of the pigment ink 54 by the electrostatic force. As a result, many color material particles 5
The particle group 59 including the particles 8 flies from the tip end 641 of the discharge electrode 64 and adheres to the recording body 62. Subsequently, the supply of the pigment-based ink 54 is performed, and such an operation is repeated to form an image on the recording body 62.

[0005]

In these operations, after the pulsed discharge voltage Vb is applied, the next discharge voltage Vb is applied.
The longer the time t ₁ until b is applied, the smaller the electrostatic force for moving to the tip 641 of the discharge electrode 64. In this case, due to the surface tension acting on the ink meniscus 541, as shown in FIG.
1 degenerates. As a result, as shown in FIG. 6, most of the color material particles 58 are returned to the base 642 side of the discharge electrode 64, and the concentration of the color material particles 58 is reduced at the tip end 641 of the discharge electrode 64. Therefore, when the time t ₁ is long, when the next discharge voltage Vb is applied, it takes time for the color material particles 58 to move to the tip end 641 of the discharge electrode 64, so that the flight delay of the color material particles 58 and There is a problem that non-ejection occurs and adversely affects image quality.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink jet printer apparatus capable of stably discharging color material particles even when the time during which the color material particles are not discharged from the ink discharge port continues, thereby improving image quality. Is to provide.

[0007]

According to the present invention, there is provided an ink chamber having an ink discharge port and filled with a pigment-based ink, and a color material particle in the pigment-based ink is transferred to the ink discharge port by an electrophoretic phenomenon. An electrophoretic electrode to be concentrated, a discharge electrode for causing the color material particles concentrated at the ink ejection port to fly onto a recording medium, and a voltage applied to the electrophoretic electrode or the discharge electrode based on print information output from a host device. This is an improvement of the ink jet printer device provided with an applied voltage control unit for controlling. That is, the feature of the present invention is provided with off-time determining means for determining the elapsed time since the voltage applied to the discharge electrode is turned off,
The applied voltage control unit changes an applied voltage to the discharge electrode in accordance with the elapsed time determined by the off-time determining unit.

If the elapsed time is equal to or longer than a predetermined time, the applied voltage control section applies a discharge voltage to the discharge electrode to discharge the color material particles to the discharge electrode. Before the transfer, a moving voltage for moving the coloring material particles to the tip of the discharge electrode may be applied. In this case, the moving voltage may be composed of a plurality of pulse voltages having a pulse width shorter than the discharge voltage.

[0009]

The ink chamber is filled with pigment-based ink, and charged pigment particles are scattered in the pigment-based ink. Here, the applied voltage control unit moves the color material particles in the pigment-based ink to the ink ejection port by applying the migration voltage to the electrophoresis electrode. Subsequently, by applying a discharge voltage to the discharge electrode, a particle group including a large number of color material particles is caused to fly from the ink discharge port.

The off-time determining means determines the elapsed time from when the voltage applied to the discharge electrode is turned off. As the elapsed time becomes longer, the color material particles concentrated on the tip of the discharge electrode decrease. Therefore, the applied voltage control unit changes the applied voltage to the discharge electrode according to the elapsed time determined by the off-time determining means.

[0011]

FIG. 1 is a block diagram showing an embodiment of an ink jet printer according to the present invention. Hereinafter, description will be made based on this drawing. In FIG. 1, FIG.
The same reference numerals are given to the same parts as.

The ink jet printer device 10 includes a head unit 50 and an applied voltage control unit 14.

The head section 50 has an ink discharge port 52 and is filled with a pigment-based ink 54 in an ink chamber 56, and the color material particles 58 in the pigment-based ink 54 are concentrated on the ink discharge port 52 by an electrophoretic phenomenon. Electrophoretic electrode 60 for causing colorant particles 5 to concentrate on ink ejection port 52
And a discharge electrode 64 for causing the recording material 8 to fly onto the recording body 62.

The electrophoretic electrode 60 is formed in a U-shaped cross section as shown. An ink ejection port 52 is provided at the center of the opening of the electrophoresis electrode 60. The ink chamber 56 is made of a dielectric material such as a synthetic resin, and is formed so that the cross-sectional area of the ink chamber 56 gradually decreases toward the ink ejection port 52. The discharge electrode 64 is disposed in the ink chamber 56 near the ink discharge port 52.

The applied voltage control section 14 comprises an off-time determining means 40, a voltage applying circuit 42, a control circuit 44, etc., and based on the print information 30a output from the host device 30, the electrophoretic voltage Va of the electrophoretic electrode 60. And discharge electrode 64
And the discharge voltage Vb is changed in accordance with the elapsed time T determined by the off-time determining means 40. The host device 30 is a personal computer or the like, and the print information 30a is print data and a print control signal.

The voltage application circuit 42 includes a transistor for applying a DC voltage to the electrophoresis electrode 60 or the discharge electrode 64. The voltage application circuit 42 converts the migration voltage Va, the discharge voltage Vb, and the movement voltage Vc according to a print signal 44a from the control circuit 44. Output. The control circuit 44 includes an input / output interface, CP
U, ROM, RAM, and the like, and performs predetermined control according to a program stored in the ROM or the like. The off-time determining means 40 in the present embodiment is realized by a program stored in the ROM of the control circuit 44, and determines the elapsed time T after the discharge voltage Vb is turned off. The information on the discharge voltage Vb is the print information 30a.
And the print signal 44a.

Next, the general operation of the ink jet printer 10 will be described.

By applying a DC voltage V ₁ (FIG. 5) as an electrophoresis voltage Va to the electrophoresis electrode 60, the ink chamber 5
6 when the electric field is applied, the color material particles 58 in the pigment ink 54
Moves to the ink ejection port 52, so that the ink ejection port 52
Concentration of the coloring material particles 58 occurs. With the color material particles 58 concentrated, the print information 30 a is input to the control circuit 44 from the host device 30. The control circuit 44 controls the print information 30
The print signal 44a is output to the voltage application circuit 42 based on the signal a. The voltage application circuit 42 responds to the print signal 44a,
A rectangular wave having a DC voltage V ₂ and a time t ₂ (FIG. 5) is applied to the discharge electrode 64 as the discharge voltage Vb. When the discharge voltage Vb is applied to the discharge electrode 64, an electric field toward the recording body 62 acts near the ink discharge port 52. Due to the Coulomb force based on this electric field, the color material particles 58 near the ink ejection port 52 fly as a group of particles 59 and adhere to the recording body 62. Subsequently, the pigment-based ink 54 is supplied, and the same operation is repeated to form an image on the recording medium 62.

FIG. 2 shows an ink jet printer device 10.
FIG. 7 is a waveform diagram showing an electrophoretic voltage Va and a discharge voltage Vb in an example of the characteristic operation of FIG. Hereinafter, description will be given based on FIG. 1 and FIG.

The control circuit 44 determines the discharge voltage Vb to be applied to the discharge electrode 64 in accordance with the print information 30a input from the host device 30, and outputs it to the voltage application circuit 42 as a print signal 44a. Here, as shown in FIG.
A first discharge voltage Vb ₁ , a first elapsed time t ₃ , a second discharge voltage Vb ₂ , a second elapsed time t ₄ , a third discharge voltage Vb ₃ ,
Third elapsed time t _5, the order of the fourth discharge voltage Vb _4, print information 30a is higher-level device that applies a discharge voltage Vb 3
It is assumed that the signal is output from 0 to the control circuit 44. The off-time determining means 40 determines that the elapsed time T is t from the print information 30a.
_3, extracts the t ₄ and t _5. The control circuit 44 determines that the elapsed time t ₅ among the elapsed times t ₃ , t ₄ , and t ₅ is equal to the fixed time S
It determines that at least _one, before applying the discharge voltage Vb _4, applies the moving voltage Vc. The moving voltage Vc is adjusted so that the coloring material particles 58 move to the tip end portion 641 of the discharge electrode 64 but do not fly as the particle group 59, for example, the DC voltage V ₂ and the time t. ₆ (<
t ₂ ) consisting of three rectangular waves. When the moving voltage Vc is applied, the coloring material particles 58 move as shown in FIG.
4 moves to the front end portion 641. Thereafter, the discharge voltage Vb ₄ is applied to the discharge electrode 64. At this time, since the distal end 641 of the discharge electrode 64 color particles 58 is already concentrated, the discharge voltage Vb ₄ to the discharge electrode 64 is applied, it flies without the particles 59 behind the recording Attaches on body 62.

In order to achieve the same operation and effect,
The voltage value of the discharge voltage Vb may be changed.

[0022]

According to the ink jet printer of the present invention, there is provided an off-time judging means for judging an elapsed time after the voltage applied to the discharge electrode is turned off, and the elapsed time determined by the off-time judging means is provided. Since the applied voltage to the discharge electrode is changed according to the time, the coloring material particles are concentrated at the tip of the discharge electrode even if the elapsed time from when the applied voltage to the discharge electrode is turned off becomes long. Can be done. Therefore, it is possible to prevent a flight delay and non-ejection of the color material particles when the elapsed time from when the voltage applied to the discharge electrode is turned off becomes long, thereby improving the image quality.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of an ink jet printer device according to the present invention.

FIG. 2 is a waveform diagram illustrating an example of a migration voltage and a discharge voltage in the inkjet printer of FIG.

FIG. 3 is a sectional view showing a head section of a conventional ink jet printer device.

FIG. 4 is a partially enlarged view showing an example of the vicinity of the tip end of a discharge electrode in FIG. 1 or FIG.

FIG. 5 is a waveform diagram showing an example of a migration voltage and an ejection voltage in the ink jet printer of FIG. 1 or FIG.

FIG. 6 is a partially enlarged view showing another example near the distal end of the discharge electrode in FIG. 3;

DESCRIPTION OF THE SYMBOLS 10 Inkjet printer device 14 Applied voltage control unit 40 Off time judgment means 50 Head unit 52 Ink ejection port 54 Pigment ink 56 Ink chamber 58 Color material particles 59 Particle group 60 Electrophoretic electrode 62 Recording body 64 Discharge electrode Va migration voltage Vb discharge voltage Vc transfer voltage

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Ryosuke Agematsu 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation (72) Inventor Kazuo Shima 5-7-1 Shiba, Minato-ku, Tokyo NEC (56) References JP-A-9-1824 (JP, A) JP-A-8-90825 (JP, A) JP-A-2-160557 (JP, A) JP-A-56-40563 (JP, A A) International Publication 93/11866 (WO, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2/06 B41J 2/385

Claims (3)

(57) [Claims] An ink chamber having an ink ejection port and filled with a pigment-based ink; an electrophoretic electrode for concentrating color material particles in the pigment-based ink on the ink ejection port by an electrophoretic phenomenon; A discharge electrode for flying the color material particles concentrated on the ink discharge port onto the recording medium, and an applied voltage control unit for controlling an applied voltage to the electrophoretic electrode or the discharge electrode based on print information output from a host device. In the ink jet printer device provided with, an off time determining means for determining an elapsed time from when the applied voltage to the discharge electrode is turned off is provided, and the applied voltage control unit is determined by the off time determining means. An ink jet printer device, wherein a voltage applied to the discharge electrode is changed according to the elapsed time. 2. The ink jet printer according to claim 1, wherein the applied voltage control unit discharges the color material particles to the discharge electrode if the elapsed time is equal to or longer than a predetermined time. An ink jet printer device, wherein a moving voltage for moving the color material particles to the tip of the discharge electrode is applied before applying the voltage. 3. The ink-jet printer according to claim 2, wherein the moving voltage comprises a plurality of pulse-shaped voltages having a pulse width shorter than the discharge voltage.