JP2885734B2 - 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 in which coloring material particles in a pigment ink are controlled by an electrophoretic phenomenon.

[0002]

2. Description of the Related Art FIGS. 3, 4 and 5 show a conventional electrostatic ink jet recording apparatus. FIG. 3 is a schematic view of an electrostatic ink jet recording apparatus using the electrophoretic phenomenon, FIG. 4 is a plan view of the electrostatic ink jet recording apparatus using the electrophoretic phenomenon, and FIG. 5 is an application to an electrophoretic electrode and a discharge electrode. It is a voltage waveform diagram.

An electrostatic ink jet recording apparatus having a plurality of ejection electrodes is, as shown in FIG.
And the color material particles 33 in the pigment ink 32 shown in FIG.
Electrophoretic electrode 124 for concentrating on the recording medium 3 and discharging the color material particles 33 concentrated on the ink discharge port 102
The recording medium 30 includes a plurality of ejection electrodes 21 for flying above the recording medium 30, and a plurality of ejection electrodes 21 that are arranged on the back surface of the recording medium 30 so as to face the ejection electrodes 21. The ink ejection port 102 is provided for each ejection electrode 2
Each of the discharge electrodes is partitioned by a flow path wall 108 so that a meniscus 116 of the pigment-based ink 32 having a convex shape as shown in FIG. The ink chamber 131 is connected to an ink tank (not shown) by an ink supply port 106 and an ink discharge port 107 via a tube.
The back pressure is applied to the ink inside the ink chamber 131, and the pigment ink 32 in the ink chamber 131 is forcibly circulated.

Next, the operation will be described. This method utilizes an electrophoresis phenomenon in which, when an electric field is applied to a pigment-based ink containing charged coloring material particles, the coloring material particles move in one direction under the electric field. That is, when the voltage of the constant voltage V1 shown in FIG. 5 is applied to the electrophoretic electrode 124 and an electric field is applied to the ink chamber 131 filled with the pigment-based ink 32, the coloring material particles 33 in the pigment-based ink 32 are discharged from the ink ejection port. Move to 102 at a certain electrophoretic speed. When the color material particles 33 move to the ink ejection port 102, a meniscus 116 is generated. FIG. 5 shows the discharge electrode 21 for discharging the color material particles 33.
4 is turned on, the driver 103 shown in FIG. 4 is turned on, and the coloring material particles 33 are displaced by the electrostatic field generated between the ejection electrode 21 and the counter electrode 22. Move to the tip of and concentrate.
The particles overcome the surface tension, viscous force, etc. of the pigment ink by the electrostatic force, and the fine flying particle group 1 as shown in FIG.
At 11, it flies from the tip of the discharge electrode 21 and adheres to the recording medium 30. Thereafter, replenishment of the color material particles 33 is performed, and such an operation is repeated to form an image on the recording medium 30.

FIG. 6 is a plan view showing a case where a gate electrode is used in an electrostatic ink jet recording apparatus utilizing the electrophoresis phenomenon, and shows an operation of discharging color material particles.
FIG. 7 is a waveform diagram of a voltage applied to the ejection electrode, the migration electrode, and the gate electrode.

This method is similar to the above-described method of discharging color material particles using an electrostatic field generated between a discharge electrode and a counter electrode, and is a pigment-based ink containing charged color material particles. The electrophoretic phenomenon in which coloring material particles move in one direction under an electric field when an electric field is applied to the material is used.

The gate electrode 23 is located between the discharge electrode 21 and the counter electrode 22 disposed at a position facing the ink discharge port 102 via the recording medium 30, and a portion facing the ink discharge port 102. Is provided with a slit 112 and is open. The voltage of the constant voltage V1 shown in FIG. 7 is applied to the electrophoresis electrode, and the ink chamber 1 filled with the pigment-based ink.
When an electric field is applied to 31, the color material particles 33 in the pigment-based ink move to the ink ejection port 102 at a certain electrophoretic speed. When the color material particles 33 move to the ink ejection port 102, a meniscus 116 is generated. When the voltage V2 shown in FIG. 7 and the pulse-shaped discharge voltage Vej of time T2 are applied to the discharge electrode 21 for discharging the color material particles 33, the driver 103 shown in FIG. Occurs. In synchronization with this, the voltage -V is applied to the gate electrode 23 as shown in FIG.
3. When a pulse-like ejection voltage VGT at time T2 is applied,
The driver 104 shown in FIG. 6 is turned on, and -V3 is generated at the gate electrode 23. Here, a potential difference of V2-(− V3) is generated between the discharge electrode 21 and the gate electrode 23, and the color material particles 33 move and concentrate at the tip of the discharge electrode 21 due to the electrostatic field. The particles overcome the surface tension, viscous force and the like of the pigment ink 32 by the electrostatic force, and become fine flying particles 111 as shown in FIG. From the tip of the recording medium 30 and adheres onto the recording medium 30. Thereafter, replenishment of the color material particles 33 is performed, and such an operation is repeated to form an image on the recording medium 30.

[0008]

In the conventional electrostatic ink jet recording apparatus described above, the conventional recording head driving means as shown in FIG. 6 requires one driver for one discharge electrode. When driving multi-heads arranged in tens of rows or line heads connected in hundreds to thousands of rows, there is a problem that the number of drivers increases accordingly and the driving circuit becomes large-scale. . In addition, there is a problem in that the device becomes large in size and the number of drivers increases, thereby increasing the cost.

An object of the present invention is to reduce the number of drivers,
It is an object of the present invention to provide an electrostatic ink jet recording apparatus in which the size and cost of the apparatus are reduced by downsizing the driving circuit.

[0010]

According to the electrostatic ink jet recording apparatus of the present invention, an electric field is applied to a pigment-based ink containing charged coloring material particles, and ink droplets are ejected by Coulomb force acting on the coloring material particles. In an electrostatic ink jet recording apparatus that performs printing on a recording medium, an electrophoretic electrode for concentrating color material particles in the pigment-based ink on an ink discharge port by an electrophoretic phenomenon, and the electrophoretic electrode concentrated on the ink discharge port. A plurality of discharge electrodes for discharging color material particles, a counter electrode disposed at a position facing the ink discharge port via the recording medium, and the discharge electrode positioned between the recording medium and the discharge electrode; ink discharge ports opposed to the portion and a gate electrode having an opening in a slit shape or a nozzle shape, the plurality
Ejection electrode groups consisting of m ejection electrodes
And applying a voltage for each of the ejection electrode groups
discharge electrode control means having n voltage application means for controlling the same; and q sets of electrophoresis electrodes each comprising p electrophoresis electrodes.
Divided into moving electrode blocks and separated by the electrophoresis electrode blocks
And an electrophoretic electrode control means for controlling by having q voltage applying means for applying a voltage to the electrophoretic electrode.

In the electrostatic ink jet recording apparatus of the present invention, the discharge electrode control means performs time division in a recording cycle for discharging the color material particles, and synchronizes with each timing in the time division. It is also possible to drive and control it.

In the electrostatic ink jet recording apparatus according to the present invention, the electrophoretic electrode control means performs time division in a recording cycle in which the color material particles are discharged. Driving and control may be performed in synchronization.

In the electrostatic ink jet recording apparatus according to the present invention, the recording cycle for discharging the color material particles is time-divided into 1 / m or 1 / n, and the number of the electrophoretic electrodes is n.
It may be divided into m sets of electrophoresis electrode blocks .

In the electrostatic ink jet recording apparatus of the present invention, the values of m and n may be selected so that the value of m + n is minimized.

[0015]

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

FIG. 1 is a schematic circuit diagram of the recording head driving means in the discharge electrode control means and the electrophoresis electrode control means.

The recording head control means of the present invention can be roughly divided into discharge electrode control means and electrophoresis electrode control means. In the present embodiment, a multi-head having 800 ejection electrodes will be described as an example.

The discharge electrode control means sets the discharge electrode 21 to the discharge electrode No. , 701,..., 701 are a first group. 2, 102, 202, ...
.., 702 represent the second group, and 100, 2
.., 800 are divided into 100 groups up to the 100th group, and the ejection electrodes 21 of each group are connected by the same signal. The first group is connected to the ejection electrode driver 3, and the other end is connected to the ejection electrode power supply 5 that supplies a voltage to the ejection electrode 21.
The switch sections of these drivers are turned on and off by the discharge electrode control section 6 to supply and cut off voltage to the discharge electrodes 21 of each group.

The electrophoretic electrode control means controls the electrophoretic electrode 24 divided into eight blocks by supplying or shutting off the electrophoretic electrode power supply 7. The electrophoretic electrodes 24 provided in each block move the coloring material particles 33 in the ink chamber 31 filled with the pigment-based ink 32 to the ink discharge port by applying a constant voltage to form a meniscus. . The migrating electrode group 1 has ejection electrode Nos. No. 1 to No. The electrophoresis electrodes 24 for moving the color material particles 33 to 100 are connected to the electrophoresis electrode driver 1, and the other ends are connected to the electrophoresis electrode power supply 7. Similarly, for the discharge electrode 21 No. No. 201 to No. 3
The electrophoretic electrodes 24 that move the color material particles 33 at 00 are group 2 and are connected to the electrophoretic electrode driver 2. The electrophoretic electrodes 24 that are blocked are connected to individually provided electrophoretic electrode drivers up to the electrophoretic electrode group 8 provided thereafter, and are controlled to be turned on and off by the electrophoretic electrode control unit 8. Thus, a voltage is supplied to or cut off from the electrophoresis electrode of each block.

FIG. 2 is a diagram showing voltage waveforms applied to a plurality of ejection electrodes and electrophoresis electrodes. With reference to FIG. 2, an operation of discharging the color material particles from the discharge electrodes will be described.

The electrophoresis electrode control section 8 sequentially outputs from A to H electrophoresis electrode control signals obtained by time-dividing the recording cycle T into eight equal parts, for eight electrophoresis electrode drivers. Therefore, during the period in which the migration electrode control signal A output to the migration electrode driver 1 is turned on ((1/8) × T time, part 1 in the drawing), the ejection electrode No. A migration electrode voltage is applied to 1 to 100 migration electrode groups 1. Thereby, the discharge electrode N
o. The coloring material particles 33 are provided in 1 to 100 by the electrophoresis phenomenon.
Moves, and a meniscus is formed at the discharge port. Similarly, the electrophoresis electrode voltage is supplied to the electrophoresis electrodes 24 of the electrophoresis electrode group 2 to the electrophoresis electrodes 24 of the group 8 for (１ ／) × T time, so that a meniscus is sequentially formed at the ink ejection port. The ejection electrode control unit 6 receives the ejection electrode No. from the image control unit (not shown). When the ejection command is received as having image information in 1,
Through the ejection electrode control signal D1, a signal for turning on the ejection electrode driver 3 is output (part in the figure). 1
The ejection electrode voltage is applied to a first group of 101, 201,... As described with reference to FIG. 1 described above, the discharge electrode No. in which the meniscus is formed by applying the electrophoretic electrode voltage (1 part in the figure). In FIG. 1, an electrostatic field sufficient to discharge the color material particles 33 is generated between the discharge electrode 21 and the gate electrode 23, and as shown in FIG. The discharge electrode No. 1
From the front end portion, passes through a slit provided in the gate electrode 23, and adheres to the recording medium 30. Here, the ejection electrode No. In the same manner as in the case of the first embodiment, the ejection electrode No. 101, 201, ..., 7
In No. 01, since no electrophoretic electrode voltage was applied, a meniscus was not formed at those discharge ports, and
No 3 is ejected. On the other hand, in the case where there is no image information and the color material particles are not discharged, the discharge electrode Nos. 2 will be described as an example. The ejection electrode control unit 6 receives the ejection electrode No. from the image control unit (not shown). When the ejection command is received indicating that there is no image information in the ejection electrode No. 2, a signal for turning off the ejection electrode driver 4 is output through the ejection electrode control signal D2 (portion (1) in the drawing). 102, 202 including 2,
.., And 702, the ejection electrode voltage is not applied. Thereby, the discharge electrode No. No discharge is performed because no electrostatic field sufficient to discharge the color material particles 33 between the gate electrode 2 and the gate electrode 23 is generated. FIG. 2
In the ejection electrode No. In the case of discharging from the discharge electrode 100, the discharge electrode control signal D100 is turned on to change the discharge electrode voltage to the discharge electrode N in a section (part 1 in the drawing) where the electrophoretic electrode voltage is applied to the discharge electrode and a meniscus is formed.
o. 2 can be discharged.

As described above, when it is desired to discharge the color material particles from an arbitrary discharge electrode in response to the discharge command with the image data present, in the section corresponding to the electrophoretic electrode to which the voltage is applied in a divided manner, By applying a discharge electrode voltage to the discharge electrodes. Therefore, when the discharge electrode control signal is turned on as shown in FIG. Discharge from No. 1 Part (1) in FIG. No discharge from No. 2 [1] part in the figure: discharge electrode No. 100 from the discharge electrode No. 100 Discharge from No. 101 Part (2) in FIG. Ejection from No. 102 [2] part in the drawing: Ejection electrode No. No discharge from No. 200. In the middle part of the figure: discharge electrode No. Ejection from 701 Ejection electrode No. (8) in FIG. No discharge from 702 [8] part in the figure ... discharge electrode No. Ejection starts at 800.

In this embodiment, the ejection electrode is divided into 100 and the electrophoresis electrode is divided into eight. However, if it is difficult to subdivide the ejection electrode due to a problem such as head manufacturing, the electrophoresis is performed. The same effect can be obtained by a configuration in which the electrode is divided into 100 and the ejection electrode is divided into eight.

According to the present embodiment, in a multi-head having 800 ejection electrodes, conventionally, one ejection electrode is driven by one driver, and a total of 800 drivers are required. +100, ie 1
It can be driven by 08 drivers.

In this embodiment, 108 drivers are used. However, the number of drivers can be further reduced by arbitrarily combining the migration electrode driver and the ejection electrode driver. For example, a configuration of 16 migration electrode drivers + 50 ejection electrode drivers = 66, or a configuration of 32 migration electrode drivers + 25 ejection electrode drivers = 57 is also possible. That is, the number of drivers can be minimized by optimally selecting the number of groups of ejection electrodes and the number of divisions of electrophoretic electrodes.

[0026]

As described above, according to the present invention, the electrophoretic electrodes for concentrating the color material particles in the pigment-based ink at the ink discharge ports by the electrophoretic phenomenon are divided into a plurality of electrodes and voltages are individually applied. Electrophoretic electrode control means for controlling and controlling, and discharge electrode control means for controlling a plurality of discharge electrodes for discharging the color material particles concentrated on the ink discharge ports by applying a voltage individually by grouping the plurality of discharge electrodes. Recording head driving means. By driving and controlling them in combination, the number of drivers can be reduced, and there is an effect that the size and cost of the device can be reduced by downsizing the drive circuit.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram of a recording head driving unit in an ejection electrode control unit and an electrophoresis electrode control unit of the present invention.

FIG. 2 is a waveform diagram of voltage applied to a plurality of ejection electrodes and electrophoresis electrodes of the present invention.

FIG. 3 is a schematic view of a conventional electrostatic ink jet recording apparatus utilizing an electrophoretic phenomenon.

FIG. 4 is a simple basic structural view (plan view) of a conventional electrostatic ink jet recording apparatus.

FIG. 5 is a waveform diagram of a voltage applied to a conventional discharge electrode and an electrophoretic electrode.

FIG. 6 is a plan view when a gate electrode of a conventional electrostatic ink jet recording apparatus is used.

FIG. 7 is a waveform diagram of a voltage applied to a conventional ejection electrode, electrophoresis electrode, and gate electrode.

DESCRIPTION OF THE SYMBOLS 1 migration electrode driver 2 migration electrode driver 3 discharge electrode driver 4 discharge electrode driver 5 discharge electrode power supply 6 discharge electrode control unit 7 migration electrode power supply 8 migration electrode control unit 21 discharge electrode 22 counter electrode 23 gate electrode 24 electricity Electrophoresis electrode 30 Recording medium 31 Ink chamber 32 Pigment ink 33 Color material particles 102 Ink ejection port 103 Driver 104 Driver 106 Ink supply port 107 Ink outlet 108 Flow path wall 111 Flying particle group 116 Meniscus 124 Electrophoresis electrode 131 Ink chamber

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hitoshi Minemoto 7546 Yasuda, Kashiwazaki-shi, Niigata Niigata Nippon Electric Co., Ltd. (72) Inventor Kazuo Shima 7546, Yasuda, Kashiwazaki, Niigata Niigata Nippon Electric Inside the company (72) Inventor Yoshihiro Hagiwara 7546 Yasuda, Kashiwazaki-shi, Niigata Prefecture Inside Niigata Nippon Electric Co., Ltd. Field (Int.Cl. ⁶ , DB name) B41J 2/06

Claims (5)

(57) [Claims] 1. An electrostatic ink jet recording apparatus which applies an electric field to a pigment-based ink containing charged coloring material particles, ejects ink droplets by Coulomb force acting on the coloring material particles, and performs printing on a recording medium. An electrophoretic electrode for concentrating the color material particles in the pigment-based ink on the ink discharge port by an electrophoretic phenomenon, and a plurality of discharge electrodes for discharging the color material particles concentrated on the ink discharge port; A counter electrode disposed at a position opposed to the ink ejection port via a recording medium; and a portion facing the ink ejection port located between the recording medium and the ejection electrode is opened in a slit shape or a nozzle shape. A plurality of discharge ports,
The output electrodes are collected in n sets of ejection electrode groups consisting of m pieces.
N units that combine and apply a voltage for each of the ejection electrode groups
Discharge electrode control means having and controlling voltage application means ,
Q sets of electrophoresis electrodes each comprising p electrophoresis electrodes
Electrode block and separate the
And an electrophoretic electrode control means for controlling by having q voltage applying means for applying pressure . 2. The discharge electrode control means performs time division in a recording cycle in which the color material particles are discharged, and drives and controls in synchronization with each timing in the time division. The electrostatic ink jet recording apparatus according to claim 1, wherein 3. The electrophoretic electrode control means performs time division in a recording cycle in which the color material particles are ejected, and drives and controls in synchronization with each timing in the time division. The electrostatic ink jet recording apparatus according to claim 1 or 2, wherein: 4. A recording cycle for discharging the color material particles is set to one.
/ M or 1 / n, and the number of the electrophoresis electrodes is n
4. The electrostatic ink jet recording apparatus according to claim 3, wherein the electrostatic ink jet recording apparatus is divided into m sets of electrophoretic electrode blocks each comprising: 5. The electrostatic ink jet recording apparatus according to claim 4, wherein the values of m and n are selected so that the value of m + n is minimized.