JPH08258281A - Ink ejection device - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide an ink ejection device capable of removing dust and dirt in ink without causing clogging even with an ink filter having a fine mesh. An ink tank 2 containing an ink 1, an ink filter 4 provided in communication with the ink tank 2,
Common ink chamber 3 provided in communication with the ink filter 4
A plurality of nozzles 5 communicating with the common ink chamber 3, an ink ejection portion corresponding to the plurality of nozzles 5, and an ink tank 2.
At least one pair of electrodes 1 having different surface areas
2, 13 and an AC voltage application unit for applying an AC voltage to the pair of electrodes having different surface areas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has an ink tank,
The present invention relates to an ink ejecting device that ejects ink in the ink tank as needed.

[0002]

2. Description of the Related Art In recent years, there have been increasing demands for printers to achieve high-speed printing, color printing, and low noise, and in particular, ink jet printers using ink jet heads have attracted attention.

Ink jet head systems are roughly classified into a continuous system and an on-demand system. This on-demand method includes a Kaiser method, a stem method, and a Gould method that are driven by a piezo element, a bubble jet method that causes bubbles to be generated by heat from a heater, and ink is ejected due to a change in the volume, and a conductive ink is directly electrically charged. There is an energization bubble method in which the ink is self-heated by flowing the ink to generate bubbles, and the volume of the bubbles changes to fly the ink. Among these, the bubble jet method in which an ink flow path and a pressure generating unit are provided for each nozzle and ink droplets are ejected in response to a signal is accompanied by a large number of ink flow paths due to high density which has been increasing in demand in recent years. There is a need to manufacture in a narrow range.

FIG. 6 is a sectional perspective view showing a conventional ink jet device of the bubble jet type. In FIG. 6, 1
Is a tank, 2 is an ink tank containing the ink 1, 3 is a common ink chamber filled with the ink 1, 4 is an ink filter provided between the ink tank 2 and the common ink chamber 3, and 5 is the ink 1 Nozzle for discharging, 9 is the surface to be printed,
A is an ink flow.

FIG. 5 is a partially enlarged view of the nozzle 5 of the conventional ink ejection device shown in FIG.
In FIG. 5, 5 is a nozzle for ejecting the ink 1, 6 is a heater disposed between the nozzle 5 and the common ink chamber 3, and 7
Is a voltage applying section, 8 is a switch for connecting and disconnecting the output voltage of the voltage applying section 7, 10 is an ink droplet ejected from the nozzle 5, 11 is an ink replenishing port for replenishing the ink tank 2 with the ink 1 when necessary. Is.

The operation of the conventional ink ejecting apparatus having the above structure will be described below. When a voltage is applied to the heater 6 from the voltage application unit 7 by the ON operation of the switch 8, the surface of the heater 6 generates heat, and the heat causes a part of the ink 1 on the surface of the heater 6 to vaporize. Further, the vaporized vapor of the ink 1 expands until a sufficient pressure is generated to eject the ink droplet 10 from the nozzle 5 onto the printing surface 9. By selecting the heater 6 that applies a voltage from the plurality of heaters 6 with the switch 8, the nozzle 5 that ejects the ink 1 is selected and a desired character is formed on the surface 9 to be printed. Ink 1 with ejection
When the ink is consumed, new ink 1 is supplied from the ink tank 2 through the ink filter 4 as shown in the ink flow A.
Are supplied to the common ink chamber 3 and distributed to the nozzles 5.
At this time, the ink filter 4 removes dust and dirt in the ink 1. Further, when the ink 1 is consumed, the ink 1 is replenished through the ink replenishing port 11.

By the way, with the recent increase in the density of the nozzle arrangement, it becomes necessary to manufacture a large number of ink flow paths in a narrow range, and the size of dust and dust of the ink 1 to be eliminated becomes smaller. However, in the conventional ink ejection device, the mesh of the ink filter 4 is made finer and the management of the ink is strengthened to cope with the small dust and the dust.

[0008]

However, in the conventional ink ejecting apparatus, the mesh is supplied due to the supply of the ink 1 which is insufficiently filtered by the third party and the dust mixed when the user refills the ink 1. However, there is a problem that the fine ink filter 4 is apt to be clogged and the ink supply becomes unstable.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an ink ejection device capable of removing dust and dirt in ink without causing clogging even with an ink filter having a fine mesh. And

[0010]

In order to achieve this object, an ink ejection device according to claim 1 of the present invention comprises an ink tank for containing ink, and an ink filter provided in communication with the ink tank. A common ink chamber provided in communication with the ink filter, a plurality of nozzles in communication with the common ink chamber, and an ink ejection unit corresponding to the plurality of nozzles,
It has a configuration including at least a pair of electrodes having different surface areas and provided in the ink tank, and an AC voltage applying unit for applying an AC voltage to the pair of electrodes having different surface areas.

According to a second aspect of the present invention, there is provided an ink ejection device according to the first aspect, in which the ink filter is
The structure has an equivalent diameter smaller than the diameter of the nozzle hole.

According to a third aspect of the present invention, there is provided an ink ejection device according to the first aspect, wherein at least a part of the pair of electrodes having different surface areas is covered with a dielectric.

According to a fourth aspect of the present invention, there is provided the ink ejection device according to the third aspect, wherein the dielectric has a volume resistivity lower than that of the ink.

[0014]

With this configuration, when an AC voltage is applied to a pair of electrodes having different surface areas, the electrodes can adsorb dust and dust in the ink, so that large dust and dust that cause clogging Even when the ink filter is removed from the inside and the mesh size is set to remove small dust and dust, the ink filter is not clogged.

Further, by making the equivalent diameter of the ink filter smaller than the diameter of the nozzle hole, it is possible to prevent clogging of the nozzle hole.

Further, since the pair of electrodes having different surface areas are at least partially covered with the dielectric, the electrodes do not come into direct contact with the ink in a part thereof, and the change with time of the electrodes is small. Can be

Further, by making the volume resistivity of the dielectric covering the pair of electrodes having different surface areas smaller than that of the ink, the voltage drop due to the dielectric is suppressed,
The influence of the dielectric on the electric field generated by the electrodes can be reduced.

[0018]

【Example】

(Embodiment 1) Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
Will be explained.

FIG. 1 is a sectional perspective view showing an ink ejecting apparatus according to an embodiment of the present invention. In FIG. 1, 1 is ink, 2 is an ink tank, 3 is a common ink chamber, 4 is an ink filter, 5 is a nozzle, 9 is a surface to be printed, 11 is an ink replenishing port, and A is an ink flow. Since it is the same as that of 6, the same reference numerals are given and the description thereof is omitted. 12
Is a rod-shaped adsorption electrode, and 13 is a large planar electrode.

FIG. 2 is an operation explanatory view for explaining the dust adsorption operation in one embodiment of the present invention. In FIG. 2, 12 is a bar-shaped adsorption electrode, 13 is a large planar electrode, 1
Reference numeral 4 is an AC voltage applying portion, 15 is dust existing in the ink 1, 16 is a dielectric film which is a dielectric film covering the adsorption electrode 12 and the large electrode 13, and B is an equipotential line.

FIG. 3 is an operation principle explanatory view for explaining the principle of the dust adsorption operation in one embodiment of the present invention. In FIG. 3, 15 is dust existing in the ink 1, C is a line of electric force, and E1 and E2 are electric field strengths.

FIG. 4 is a perspective view showing an ink jet printer to which the ink ejection device according to one embodiment of the present invention is applied. In FIG. 4, 2 is an ink tank, 20 is a carriage for fixing the inserted ink tank 2, 21 is a guide shaft for guiding the serially reciprocating carriage 20, and 22 is a platen roller for feeding the recording paper 23.

FIG. 5 is a partially enlarged view of the portion of the nozzle 5 of the ink ejecting apparatus as described above, which has the same structure as the conventional one, and the description thereof will be omitted.

The operation of the ink ejecting apparatus constructed as above will be described with reference to FIGS. FIG.
Then, when the ink tank 2 is set in the common ink chamber 3,
An AC voltage is applied between the adsorption electrode 12 and the large electrode 13 by the AC voltage application unit 14 (FIG. 2), dust 15 and dust in the ink 1 are adsorbed to the adsorption electrode 12, dust 15 in the ink 1, Dust is removed. After that, when a voltage is applied to the heater 6 from the voltage applying section 7, the surface of the heater 6 generates heat, and the heat vaporizes part of the ink 1 on the surface of the heater 6. Further, the vaporized vapor of the ink 1 expands until a sufficient pressure is generated to eject the ink droplet 10 from the nozzle 5 onto the printing surface 9. By selecting the heater 6 that applies a voltage from the plurality of heaters 6 with the switch 8, the nozzle 5 that ejects the ink 1 is selected and a desired character is formed on the surface 9 to be printed. When the ink 1 is consumed by the ejection, as shown in the ink flow A, from the ink tank 2 through the ink filter 4,
New ink 1 is supplied to the common ink chamber 3, and the nozzle 5
Will be distributed to. At this time, the ink filter 4 removes dust 15 and dust in the ink 1. Further, when the ink 1 is consumed, the ink 1 is replenished through the ink replenishing port 11. When the replenishment is performed, the dust 15 and the dust are removed by the same operation as described above, and the ink 1 is kept in a clean state.

By repeating the above operation, the ink tank 2 mounted on the carriage 20 reciprocates along the guide shaft 21 in accordance with a print signal sent from a computer or the like (see FIG. 4). 20
The voltage application unit 7 applies a drive voltage to an arbitrary heater 6 in accordance with the position, and ink droplets 10 are continuously generated and adhere to the recording paper 23 sent by the platen roller 22,
Dots can be printed on the recording paper 23.

Next, the operation of attracting dust 15 and dust in the ink 1 will be described in detail with reference to FIG. When an AC voltage in the positive direction is applied between the adsorption electrode 12 and the large electrode 13 by the AC voltage application unit 14, since the surface areas of the electrodes 12 and 13 are different, the equipotential line B is formed in the ink tank 2. As shown in the drawing, an electric field is generated in which the electric field strength increases as it approaches the adsorption electrode 12. At this time, dust 15 present in the electric field causes dielectric polarization, and as shown in dust 15 in FIG. 3, negative charges are generated along the electric force line C perpendicular to the equipotential line B in the higher potential side. However, a positive charge is generated at the lower potential. In this case, because of dielectric polarization, the absolute values of the positive charge and the negative charge are equal. Here, when the charge amount is Q and the electric field strength is E, an electrostatic attractive force F represented by F = Q × E is generated. At this time, the adsorption electrode 12
Since the electric field strength E1 on the side of the large electrode 13 is larger than the electric field strength E2 on the side of the large electrode 13, the dust 15 that is dielectrically polarized and the dust are the adsorption electrode 1
Adsorbed on 2. Even if the AC voltage from the AC voltage applying unit 14 becomes negative and the potential is reversed, the polarization directions of the dust 15 and dust are also reversed. Therefore, for the same reason as described above, the dust 15 and dust are collected on the adsorption electrode 12. Adsorbed. Since alternating current is applied between both electrodes, no electrolytic bubbles are generated on the surfaces of both electrodes. Furthermore, since it is an alternating current, the dust 15 and dust that have released the charges do not separate from the surface of the adsorption electrode 12, and the electrodes 12 and 13 do not come into direct contact with the ink by the dielectric film 16, so that the change over time is extremely large. Few.

Although the size of the mesh of the ink filter 4 is not particularly described in this embodiment, if the equivalent diameter of the ink filter 4 is made smaller than the diameter of the hole of the nozzle 5, the ink filter 4 is transmitted. Dust, garbage 15
Is smaller than the hole of the nozzle 5, so that the nozzle 5 is not clogged. Further, in this embodiment, the entire surfaces of the electrodes 12 and 13 are covered with the dielectric film 16,
Even when the electrodes 12 and 13 are partially covered, it is possible to reduce the changes with time of the electrodes 12 and 13 depending on the width of the covered portions. Furthermore, if the volume resistivity of the dielectric film 16 is made smaller than that of the ink 1, the voltage drop due to the dielectric film 16 is suppressed, so that the influence of the dielectric film 16 on the electric field generated by the electrodes 12 and 13 is reduced. be able to.

As described above, according to this embodiment, when the AC voltage is applied to the pair of electrodes 12 and 13 having different surface areas, the adsorption electrode 12 can adsorb dust 15 and dust in the ink 1. The large dust 15 that causes clogging and dust are removed from the ink 1. Even if the mesh of the ink filter 4 is small enough to remove dust 15 and dust, the ink filter 4 is not clogged. .

[0029]

As described above, according to the present invention, the ink tank for containing the ink, the ink filter provided in communication with the ink tank, the common ink chamber provided in communication with the ink filter, and the common ink are provided. A plurality of nozzles communicating with the chamber, an ink ejecting portion corresponding to the plurality of nozzles, at least a pair of electrodes having different surface areas provided in the ink tank, and an AC voltage application for applying a voltage to the pair of electrodes having different surface areas By providing the portion, when an AC voltage is applied to the pair of electrodes having different surface areas, the electrode having a small surface area can adsorb ink dust and dust, so that large dust that causes clogging, Dust is removed from the ink, and even if the mesh of the ink filter is small dust and the size is such that dust is removed, the ink filter is clogged. It can be realized Rukoto without ink ejection device.

Further, by making the equivalent diameter of the ink filter smaller than the diameter of the hole of the nozzle, it is possible to realize an ink ejecting device which prevents clogging of the hole of the nozzle.

Further, since at least a part of the pair of electrodes having different surface areas is covered with the dielectric, the electrode does not come into direct contact with the ink in a part of the electrode. A discharge device can be realized.

Further, by making the volume resistivity of the dielectric covering the pair of electrodes having different surface areas smaller than that of the ink, the dielectric becomes a substance similar to the electrode when viewed from the ink. It is possible to realize an ink ejection device in which the influence of the dielectric on the generated electric field is small.

[Brief description of drawings]

FIG. 1 is a sectional perspective view showing an ink ejection device according to an embodiment of the present invention.

FIG. 2 is an operation explanatory view for explaining a dust suction operation in one embodiment of the present invention.

FIG. 3 is an operation principle explanatory diagram for explaining the principle of the dust suction operation in the embodiment of the present invention.

FIG. 4 is a perspective view showing an inkjet printer to which an ink ejection device according to an embodiment of the present invention is applied.

FIG. 5 is a partially enlarged view in which a nozzle portion of a conventional ink ejection device is enlarged.

FIG. 6 is a sectional perspective view showing a conventional ink ejection device.

[Explanation of symbols]

 1 Ink 2 Ink Tank 3 Common Ink Chamber 4 Ink Filter 5 Nozzle 6 Heater 7 Voltage Applying Section 8 Switch 9 Printed Surface 10 Ink Drop 11 Ink Replenishing Port 12 Adsorption Electrode 13 Large Electrode 14 AC Voltage Applying Section 15 Garbage 16 Dielectric Film 20 Carriage 21 Guide shaft 22 Platen roller 23 Recording paper A Ink flow B Equipotential line C Electric force lines E1, E2 Electric field strength

Claims (4)

[Claims] 1. An ink tank for containing ink, an ink filter provided in communication with the ink tank, a common ink chamber provided in communication with the ink filter, and a plurality of communication with the common ink chamber. Nozzle, an ink ejecting section corresponding to the plurality of nozzles, at least a pair of electrodes having different surface areas provided in the ink tank, and an AC voltage applying section for applying an AC voltage to the pair of electrodes having different surface areas. An ink ejecting device comprising: 2. The ink ejecting apparatus according to claim 1, wherein the ink filter has an equivalent diameter smaller than a diameter of the hole of the nozzle. 3. The ink ejection device according to claim 1, wherein at least a part of the pair of electrodes having different surface areas is covered with a dielectric. 4. The ink ejection device according to claim 3, wherein the dielectric has a volume resistivity smaller than that of the ink.