JP2004174846A - Liquid discharging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid discharging device which can make markedly long the time after the device has been left for a certain time before a non-discharge takes place. <P>SOLUTION: The liquid discharging device includes a liquid droplet discharging device 1 and a mechanism 21. The liquid droplet discharging device 1 has nozzles 13 set at an orifice plate 11a for discharging a liquid of a type in which a solid substance such as color material is dispersed, and liquid chambers with driving means for discharging the liquid from the nozzles 13. The mechanism 21 covers an orifice plate surface by the discharged liquid. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid ejection device that stably ejects ink from a droplet ejection device.
[0002]
[Prior art]
2. Description of the Related Art An ink jet device is known as a liquid discharge device that discharges ink from a droplet discharge device (Patent Document 1).
[0003]
In such an ink jet device, there is a problem of getting up and down. The liquid used in the droplet discharge device includes aqueous ink, oil-based ink, solvent ink, UV (ultraviolet curable) ink, and the like. Coloring materials that determine the color of the ink include those in which a dye is dissolved and those in which a pigment is dispersed.
[0004]
Pigment inks are particularly used outdoors because they have excellent light fastness and water resistance as compared with dye inks and have good coloring of black pigments.
[0005]
UV-curable inks are used because of their advantages such as curing in a short time of 1 second or less and excellent abrasion resistance.
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. Hei 7-1010084
[Problems to be solved by the invention]
However, there is a phenomenon that these inks in which solids are dispersed cannot be discharged immediately after being left without discharging droplets. It is considered that this phenomenon is caused by pigments and the like dispersed in the ink gathering at the edge of the nozzle surface and the like, and the physical properties such as the viscosity of the ink change based on the portion.
[0008]
The present invention has been made in view of the above points, and an object of the present invention is to provide a liquid ejection apparatus that can significantly increase the time until non-ejection occurs after being left for a certain period of time.
[0009]
[Means for Solving the Problems]
The present invention is directed to a droplet discharge device including a discharge hole that discharges a liquid of a type in which a solid material such as a coloring material is dispersed in an orifice plate, and a liquid chamber that has a driving unit that discharges the liquid from the discharge hole. And a function of covering the orifice plate surface with the liquid to be discharged.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1A shows an ink discharge mechanism 1 as a droplet discharge device of a liquid discharge device according to the present invention, and FIG. 1B shows a cross-sectional view along AA.
[0011]
In FIG. 1, reference numeral 11 denotes a plurality of pressure chambers for storing ink as a liquid. The orifice plate 11a facing the plurality of pressure chambers 11 is provided with a nozzle 13 for discharging ink droplets. Further, ink is supplied from the common liquid chamber 16 to each pressure chamber 11. The bottom surface of the pressure chamber 11 is formed by a vibration plate 14, and a plurality of piezoelectric members 15 are fixed to the lower surface of the vibration plate 14 corresponding to the pressure chamber 11. An actuator is constituted by the vibration plate 14 and the piezoelectric member 15, and the piezoelectric member 15 is electrically connected to an output terminal of the drive signal generating means 2.
[0012]
As the ink, for example, a UV (ultraviolet curing type) ink is used, and is composed of a coloring material, a monomer, an oligomer, a photopolymerization initiator, a dispersant, and a surface tension modifier.
[0013]
FIG. 2A is an enlarged view of the vicinity of the nozzle 13 showing one embodiment of the present invention. As shown in this figure, a liquid holding unit 21 as a mechanism for holding a liquid to be discharged and bringing the liquid into contact with the orifice plate is provided so as to contact the orifice plate 11a so as to cover the nozzle discharge port (hereinafter referred to as A). Type).
[0014]
FIG. 2B shows a comparative example, and is an enlarged view of the vicinity of the nozzle 13. As shown in this figure, a cover 31 is provided on the surface of the orifice plate 11a, but the cover 31 is not filled with a solution such as ink (hereinafter, referred to as a B type).
[0015]
FIG. 5 shows the result of examining the number of non-ejection nozzles generated when the A type and the B type were left in each state for a certain period of time and then re-ejected. As shown in FIG. 5, non-discharge nozzles occurred in the B type after 1 hour, but no discharge nozzles occurred in the A type even after 24 hours.
[0016]
This is because, in the B type, as shown in FIG. 3B, the coloring material 41 such as a pigment dispersed in the ink gathers at the edge portion 51 on the surface of the nozzle 13 and the viscosity of the ink is determined based on the portion. For example, the physical properties change, and a non-ejection occurs after being left for a certain period of time.
[0017]
However, in the embodiment, as shown in FIG. 3C, the coloring material 41 and the like dispersed in the ink do not collect on the edge portion 51 on the surface of the nozzle 13. Therefore, non-discharge does not occur after being left for a certain period of time.
[0018]
As described above, in the present embodiment, the liquid holding portion 21 as a mechanism for holding the liquid to be discharged and making contact with the orifice plate is provided so as to contact the orifice plate 11a so as to cover the nozzle discharge port. The solid matter such as the coloring material 41 dispersed therein is less likely to collect at the edge portion 51 on the nozzle surface, and the phenomenon of non-ejection of liquid droplets is reduced.
[0019]
The ink held by the liquid holding unit 21 may be filled by discharging from the nozzle 13. This alleviates the solid matter such as the coloring material 41 dispersed in the liquid from gathering at the edge portion 51 on the nozzle surface, and reduces the phenomenon that the droplet is not ejected. Further, the mechanism for holding the liquid can be simplified by introducing the liquid held in the liquid holding unit 21 from the nozzle 13.
[0020]
At this time, the pressure of the ink tank may be increased to cause the ink to flow out to the liquid holding unit 21.
[0021]
In this embodiment, the liquid to be discharged is held, and the liquid holding unit 21 as a mechanism for making contact with the orifice plate is provided so as to contact the orifice plate 11a so as to cover the nozzle discharge port. Any function that covers the surface of the orifice plate may be used.
[0022]
Further, in the above embodiment, the liquid holding unit 21 is filled with the ink, but may be filled with the ink main solvent.
[0023]
This alleviates the solid matter such as the coloring material 41 dispersed in the liquid from gathering at the edge portion 51 on the nozzle surface, and reduces the phenomenon that the droplet is not ejected. Further, by using the main solvent, the effect can be further enhanced.
[0024]
In addition, the main solvent to be discharged is held as described above, and the liquid holding unit 21 as a mechanism for contacting the orifice plate is provided so as to contact the orifice plate 11a so as to cover the nozzle discharge port. Any function that covers the surface of the orifice plate may be used.
[0025]
Further, the ink or the main solvent may be charged in another system. That is, a cover 61 may be provided on the orifice plate 11a as shown in FIG. 4A, and a tank or a main solvent may be introduced into the cover 61 from the outside as shown in FIG. 4B. Even in this case, a similar effect can be obtained.
[0026]
When ink is to be ejected again, the cover 61 is detached as shown in FIG. 4C, and the main solvent and the like in the cover 61 are discharged as shown in FIG. 4D.
[0027]
With such a configuration, the solid matter such as the coloring material 41 dispersed in the liquid is less likely to collect on the edge portion 51 on the nozzle surface, and the phenomenon that the droplet is not ejected is reduced. Further, the mechanism for discharging the liquid or the main solvent removes stains and the like at a portion to be brought into contact with the orifice plate 11a, thereby preventing the orifice plate 11a from being stained.
[0028]
By the way, when the main solvent is used, the ink concentration becomes low, so it is necessary to discharge the ink in the ink jet head at the time of reuse.
[0029]
Alternatively, a foamed member such as polyethylene or polyurethane may be provided in a portion filled with a solvent or the like in the cover 61, and the foamed member may be impregnated with the main solvent and brought into contact with the orifice plate 11a.
[0030]
This alleviates the solid matter such as the coloring material 41 dispersed in the liquid from gathering at the edge portion 51 on the nozzle surface, and reduces the phenomenon that the droplet is not ejected. By using a member impregnated with the liquid to be discharged, the liquid holding mechanism can be simplified. Further, the use of the main solvent can further enhance the effect.
[0031]
Further, a foamed member such as polyethylene or polyurethane may be provided in a portion filled with a solvent or the like in the cover 61, and ink, which is a liquid to be discharged into the foamed member, may be impregnated into contact with the orifice plate 11a.
[0032]
This alleviates the solid matter such as the coloring material 41 dispersed in the liquid from gathering at the edge portion 51 on the nozzle surface, and reduces the phenomenon that the droplet is not ejected. By using a member impregnated with the liquid to be discharged, the liquid holding mechanism can be simplified.
[0033]
As described above, by covering the surface of the orifice plate 11a with a solvent such as ink, when a liquid of a type in which a solid material such as the colorant 41 is dispersed is discharged, the liquid is not discharged until a non-discharge occurs after being left for a certain period of time. The time can be much longer.
[0034]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a liquid ejecting apparatus that can significantly increase the time until non-ejection occurs after being left for a certain period of time.
[Brief description of the drawings]
FIG. 1 is a diagram showing an ink ejection mechanism of a liquid ejection device according to an embodiment of the present invention.
FIG. 2 is an enlarged view of a nozzle portion.
FIG. 3 is a view for explaining the principle; FIG. 4 is a view showing an example of a head cover mechanism;
FIG. 5 is a diagram for explaining the time until occurrence of non-ejection.
[Explanation of symbols]
11 pressure chamber 11a orifice plate
21 ... Liquid holding part,
41 ... Coloring material,
51 ... edge part.

Claims (9)

A droplet discharge device including a discharge hole that discharges a liquid of a type in which a solid material such as a coloring material is dispersed in an orifice plate, and a liquid chamber that has a driving unit that discharges the liquid from the discharge hole;
Liquid ejection device having a function of covering the orifice plate surface with the liquid to be ejected A droplet discharge device including a discharge hole that discharges a liquid of a type in which a solid material such as a coloring material is dispersed in an orifice plate, and a liquid chamber that has a driving unit that discharges the liquid from the discharge hole;
A liquid discharging apparatus having a function of covering the surface of an orifice plate with a main solvent of a liquid to be discharged. A droplet discharge device including a discharge hole that discharges a liquid of a type in which a solid material such as a coloring material is dispersed in an orifice plate, and a liquid chamber that has a driving unit that discharges the liquid from the discharge hole;
A liquid discharge device having a mechanism for holding a liquid to be discharged and bringing the liquid into contact with an orifice plate. A droplet discharge device including a discharge hole that discharges a liquid of a type in which a solid material such as a coloring material is dispersed in an orifice plate, and a liquid chamber that has a driving unit that discharges the liquid from the discharge hole;
Liquid discharge device having a mechanism for holding a main solvent for discharge and bringing the main solvent into contact with an orifice plate A droplet discharge device including a discharge hole that discharges a liquid of a type in which a solid material such as a coloring material is dispersed in an orifice plate, and a liquid chamber that has a driving unit that discharges the liquid from the discharge hole;
A liquid ejection device having a mechanism for bringing a member impregnated with a liquid to be ejected into contact with an orifice plate. A droplet discharge device including a discharge hole that discharges a liquid of a type in which a solid material such as a coloring material is dispersed in an orifice plate, and a liquid chamber that has a driving unit that discharges the liquid from the discharge hole;
A liquid discharging apparatus comprising: a member impregnated with a main solvent of a liquid to be discharged; and a mechanism for bringing an orifice plate into contact with the member. A droplet discharge device including a discharge chamber configured to discharge a liquid of a type in which a solid material such as a coloring material is dispersed in an orifice plate, and a liquid chamber including a driving unit configured to discharge the liquid from the discharge hole.
A liquid ejecting device that contacts the liquid holding portion with the orifice plate, discharges the liquid to be ejected from the ejection hole to the liquid holding portion, and brings the liquid to be ejected into contact with the orifice plate. A droplet discharge device including a discharge hole that discharges a liquid of a type in which a solid material such as a coloring material is dispersed in an orifice plate, and a liquid chamber that has a driving unit that discharges the liquid from the discharge hole;
A liquid ejecting apparatus comprising: a mechanism for contacting a liquid holding portion with an orifice plate, discharging a liquid or main solvent to be ejected to the liquid holding portion, and bringing the liquid or main solvent to be ejected into contact with the orifice plate. A droplet discharge device including a discharge hole that discharges a liquid of a type in which a solid material such as a coloring material is dispersed in an orifice plate, and a liquid chamber that has a driving unit that discharges the liquid from the discharge hole;
After the liquid holding portion is brought into contact with the orifice plate, the liquid or main solvent to be discharged is discharged to the liquid holding portion, and the liquid or main solvent to be discharged is brought into contact with the orifice plate. And a mechanism for discharging the liquid in the liquid holding unit further apart.

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