Patent Description:
In recent years, inkjet printing technology has been applied to industrial processes. For example, a color filter manufacturing process for a liquid crystal display is an example. As an inkjet printing technique, a so-called piezo type head, which ejects a liquid droplet by mechanical pressure or vibration, has been conventionally used, but an electrostatic ejection type inkjet heads, which can eject a finer liquid droplet, is drawing attention. <CIT> discloses an electrostatic ejection type inkjet recording device. US (<CIT>) discloses a method and apparatus for mixed droplet formation, an inkjet printing method and apparatus, and a nozzle with electrode for inkjet printing, for the purpose of "providing a method and apparatus for mixed droplet formation that can accurately mix liquids independently ejected from each nozzle on a droplet forming object, an inkjet printing method and apparatus, and a nozzle with electrode for inkjet printing," including a dilution nozzle that ejects diluted liquid and two types of discharge nozzles are disclosed, including an ink nozzle.

On the other hand, in the case of the electrostatic ejection type inkjet head, there are cases in which it is difficult to eject the ink due to the electrostatic charging of an object, or the ink does not land at a desired position because it is affected by the effect of the electric field strength distributions due to an unevenness on the object.

In particular, in the case of the charging of the object itself or the pattern applied to the object affects the charging, or in the case of there is a difference of the energy between the pattern surface and the object surface, the ink may not fit well.

Therefore, one of an object of the present invention is to eject liquid droplets easily and stably onto an object surface.

According to the invention, a droplet ejection device according to claim <NUM> is provided.

According to the dependent claims, preferred embodiments of the invention are provided.

By using an embodiment of the present invention, it is possible to eject liquid droplets easily and stably onto the object surface.

Hereinafter, embodiments of the present invention disclosed in the present application will be described with reference to the drawings.

In the drawings referred to in the present exemplary embodiments, the same portions or portions having similar functions are denoted by the identical signs or similar signs (signs each formed simply by adding A, B, etc. to the end of a number), and a repetitive description thereof may be omitted. For the convenience of description, the dimensional ratio of the drawings may be different from the actual ratio, or a part of the configuration may be omitted from the drawings.

Furthermore, in the detailed description of the present invention, in defining the positional relationship between one component and another, the terms "above" and "below" include not only the case of being positioned directly above or below one component, but also the case of interposing another component therebetween, unless otherwise specified.

<FIG> is a schematic view of a liquid droplet ejection device <NUM> according to an embodiment of the present invention.

The liquid droplet ejection device <NUM> includes a control unit <NUM>, a storage unit <NUM>, a power supply unit <NUM>, a driving unit <NUM>, a first liquid droplet ejection unit <NUM>, a second liquid droplet ejection unit <NUM>, and an object holding unit <NUM>.

The control unit <NUM> includes CPU (Central Processing Unit), ASIC (Application Specific Integrated Circuit), FPGA (Field Programable Gate Array), or other calculation processing circuitry. The control unit <NUM> controls the ejection processes of the first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> by using preset liquid droplet ejection programs.

The control unit <NUM> controls an ejection timing of a first liquid droplet <NUM> (see <FIG>) from the first liquid droplet ejection unit <NUM> and an ejection timing of the second liquid droplet <NUM> (see <FIG>) of the second liquid droplet ejection unit <NUM>. As described in detail later, the ejection of the first liquid droplet <NUM> by the first liquid droplet ejection unit <NUM> and the ejection of the second liquid droplet <NUM> by the second liquid droplet ejection unit <NUM> are synchronized with each other. "Synchronizing" in the present embodiment means that the first liquid droplet <NUM> and the second liquid droplet <NUM> are ejected at a prescribed time period. In this example, the first liquid droplet <NUM> and the second liquid droplet <NUM> are ejected simultaneously. The control unit <NUM> controls the second liquid droplet ejection unit <NUM> to eject the second liquid droplet <NUM> in the first region when the first liquid droplet ejection unit <NUM> moves from the first region of an object <NUM> to the second region of the object <NUM>, on which the first liquid droplet <NUM> is ejected.

The storage unit <NUM> has a function as a data base for storing a liquid droplet ejecting program and various types of data used in the liquid droplet ejecting program. Memories, SSDs, or storable elements are used for the storage unit <NUM>.

The power supply unit <NUM> is connected to the control unit <NUM>, the driving unit <NUM>, the first liquid droplet ejection unit <NUM>, and the second liquid droplet ejection unit <NUM>. The power supply unit <NUM> applies a voltage to the first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> based on a signal input from the control unit <NUM>. In this example, the power supply unit <NUM> applies a pulsed voltage to the second liquid droplet ejection unit <NUM>. The voltage is not limited to the pulse voltage, and a constant voltage may be applied at all times.

The driving unit <NUM> includes a driving member such as a motor, a belt, and a gear. Based on an instruction from the control unit <NUM>, the driving unit <NUM> moves the first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> (more specifically, a nozzle tip 141a of a first liquid droplet nozzle <NUM> and a nozzle tip 151a of a second liquid droplet nozzle <NUM> described later) in one direction (in this example, first direction D1) with respective to the object holding unit <NUM>.

The first liquid droplet ejection unit <NUM> includes the first liquid droplet nozzle <NUM> and a first ink tank <NUM> (also referred to as a first liquid holding unit). In this embodiment, a piezo type ink jet nozzle is used as the first liquid droplet nozzle <NUM>. A piezoelectric element <NUM> is provided at the top of the first liquid droplet nozzle <NUM>. The piezoelectric element <NUM> is electrically connected to the power supply unit <NUM>. The piezoelectric element <NUM> ejects the first liquid droplet <NUM> from the nozzle tip 141a (also referred to as a first tip) of the first liquid droplet nozzle <NUM> with the first liquid held in the first ink tank <NUM> by pressing the first liquid droplet <NUM> by the voltage applied from the power supply unit <NUM>.

The first liquid droplet nozzle <NUM> in the first liquid droplet ejection unit <NUM> is provided perpendicularly to the front face of the object <NUM>.

The inner diameter of the nozzle tip 141a in the first liquid droplet nozzle <NUM> is larger than the inner diameter of the nozzle tip 151a in the second liquid droplet nozzle <NUM>. This makes it possible to eject the first liquid droplet <NUM> in a wide region while suppressing clogging of the nozzle.

The second liquid droplet ejection unit <NUM> includes the second liquid droplet nozzle <NUM> and a second ink tank <NUM> (also referred to as a second liquid holding unit). An electrostatic ejection type inkjet nozzle is used for the second liquid droplet nozzle <NUM>. The inner diameter of the nozzle tip 151a in the second liquid droplet nozzle <NUM> is several hundred nanometers or more and <NUM> or less, preferably <NUM> or more and <NUM> or less, more preferably <NUM> or more and <NUM> or less.

The second liquid droplet nozzle <NUM> has a glass tube, and an electrode <NUM> is provided inside the glass tube. In this example, a fine wire formed of tungsten is used as the electrode <NUM>. The electrode <NUM> is not limited to tungsten, and nickel, molybdenum, titanium, gold, silver, copper, platinum, or the like may be provided.

The electrode <NUM> in the second liquid droplet nozzle <NUM> is electrically connected to the power supply unit <NUM>. The second liquid held in the second ink tank <NUM> is ejected as a second liquid droplet <NUM> (see <FIG>) from the nozzle tip 151a (also referred to as a second tip) of the second liquid droplet nozzle <NUM> by voltages (in this example, 1000V) applied from the power supply unit <NUM> to the inside of the second liquid droplet nozzle <NUM> and the electrode <NUM>. By controlling the voltage applied from the power supply unit <NUM>, the shapes of the liquid droplet (patterns) formed by the second liquid droplet <NUM> can be controlled.

The first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> are arranged along a direction in which the first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> move relative to the object holding unit <NUM> (in this example, the direction D1). Specifically, the first liquid droplet ejection unit <NUM> (specifically, the nozzle tip 141a of the first liquid droplet nozzle <NUM>) is arranged in front of the second liquid droplet ejection unit <NUM> (specifically, the nozzle tip 151a of the second liquid droplet nozzle <NUM>) with respect to the directions in which the first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> move. The distances L between the first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> can be appropriately adjusted.

The object holding unit <NUM> has a function of holding the object <NUM>. For the object holding unit <NUM>, a stage is used in this instance. The mechanism by which the object holding unit <NUM> holds the object <NUM> is not particularly limited, and a common holding mechanism is used. In this example, the object <NUM> is vacuum-adsorbed to the object holding unit <NUM>. In addition, it is not limited thereto, the object holding unit <NUM> may hold the object <NUM> using a fixture.

Next, a liquid droplet ejection method is described with reference to the drawings.

First, the first liquid droplet ejection unit <NUM> and the second control unit <NUM> move onto the object <NUM> prepared in the liquid droplet ejection device <NUM> by the control unit <NUM> and the driving unit <NUM>. At this time, as shown in <FIG>, the first liquid droplet ejection unit <NUM> is arranged on the first region R1 of the object <NUM> at a certain distance from the surface of the first region R1.

The object <NUM> refers to a member in which the first liquid droplet <NUM> and the second liquid droplet <NUM> are ejected. In this embodiment, a flat glass plate is used for the object <NUM>. The object <NUM> is not limited to the flat glass plate. For example, the object <NUM> may be a metallic plate or an organic member. The object <NUM> may include a counter electrode for the liquid droplet ejection.

Next, as shown in <FIG>, the first liquid droplet ejection unit <NUM> ejects the first liquid droplet <NUM> to the first region R1.

Surface treatment liquid is used for the first liquid droplet <NUM>. It is desirable that the surface treatment liquid is highly wettable with respect to the object <NUM>. It is desirable that the surface treatment liquid remains on the object <NUM> in a certain period of time after being ejected. Specifically, it is desirable that the surface treatment liquid has a high boiling point and a low vapor pressure property. It is desirable that the surface treatment liquid has conductivity (<NUM><NUM>Ω/sq or more and <NUM><NUM> Ω/sq or less) to the extent that static electricity can be removed. Thus, it is possible to have a charge removing effect on the surface of the object <NUM>. In addition, it is desirable that the surface treatment liquid does not leave solids or the like after volatilization.

In this example, a volatile material is used for the first liquid droplet <NUM>. Specifically, a mixed liquid of ethanol and water is used for the first liquid droplet <NUM>. By using the first liquid droplet <NUM>, the surface of the object <NUM> can be appropriately neutralized, and the wettability for the surface of the object <NUM> can be improved.

The first liquid droplet <NUM> may include various kinds of alcohols, a mixed solution of the various kinds of alcohols and water, or a ketone and ether-based organic solvents with volatile properties other than alcohol in addition to water, ethanol, and a mixture of ethanol and water as a volatile material.

The ejection amount of the first liquid droplet <NUM> is not particularly limited, but is preferably such that the wettability in the object <NUM> can be improved and the charge on the surface of the object <NUM> can be removed. Specifically, in the case of a mixed liquid in which ethanol and water are mixed at <NUM>:<NUM>, it is preferable that a coating amount per <NUM> square centimeters is <NUM>. 01µl or more and 1µl or less as. In this case, thickness of the formed first liquid droplet <NUM> is <NUM> or more and <NUM> or less.

The region in which the first liquid droplet <NUM> is ejected is desirably larger than size of the pattern formed by the second liquid droplet <NUM>. This allows the second liquid droplet <NUM> to adhere more stably to the object <NUM>.

Next, as shown in <FIG>, the first liquid droplet ejection unit <NUM> moves from the first region R1 to a second region R2 on the object <NUM>. The second liquid droplet ejection unit <NUM> moves onto the first region R1 on which the first liquid droplet <NUM> is ejected, in accordance with the movement of the first liquid droplet ejection unit <NUM>. The moving speeds of the first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> are desirably set in advance to such an extent that the wettability on the subject can be maintained considering an elapsed time after the first liquid droplet <NUM> is ejected, an drying speed of the first liquid droplet <NUM>, a distance between the first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM>, and the like. In this case, it can be said that the first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> move in the direction D1.

Next, as shown in <FIG>, the first liquid droplet ejection unit <NUM> ejects the first liquid droplet <NUM> onto the second region R2 on the object <NUM> in the same manner as the first region R1. The second liquid droplet ejection unit <NUM> ejects the second liquid droplet <NUM> onto the first region R1 in synchronization with the first liquid droplet ejection unit <NUM>. In this example, the second liquid droplet ejection unit <NUM> ejects the second liquid droplet <NUM> at the same time as the first liquid droplet ejection unit <NUM> ejects the first liquid droplet <NUM>.

A material with a higher viscosity than the first liquid droplet <NUM> is used for the second liquid droplet <NUM>. Specifically, an ink (also referred to as a second liquid) for forming a pattern containing a pigment is used for the second liquid droplet <NUM>. The second liquid droplet <NUM> may include a conductive grain. The second liquid droplet ejection unit <NUM> includes an electrostatic ejection type inkjet, and the ejection amount of the second liquid droplet <NUM> is controlled by a voltage applied from the power supply unit <NUM>. It is desirable that the ejection amount of the second liquid droplet <NUM> is <NUM>. 1fl or more and 100pl or less. The pattern size in the present embodiment is <NUM> or more and <NUM> or less.

The first region R1 in which the second liquid droplet <NUM> is ejected is in a state in which the first liquid droplet <NUM> is volatilized, and does not remain or remains slightly on the surface of the object. In this case, the surface of the first region R1 is electrostatically discharged and have good wettability (lyophilic). Thus, when the second liquid droplet <NUM> is ejected onto the first region R1, it is possible to have good adhesion to the surface of the object <NUM>. Therefore, the second liquid droplet <NUM> is disposed at a predetermined position.

The first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> repeat the above processes to perform the desired liquid droplet ejection. <FIG> is a top view of the object <NUM> after the liquid droplet ejection. As shown in <FIG>, the pattern (second liquid droplet <NUM>) is disposed at a desired position on the object <NUM>. In this case, the first liquid droplet <NUM> may be volatilized or may remain partially.

Here, comparing the present invention with the prior art, in the prior art, a plasma treatment or a UV ozone treatment has been used to eliminate static electricity on the surface of the object <NUM>. However, by using this embodiment, the second liquid droplet <NUM> can be stably deposited at a predetermined position on the surface of the object <NUM>. In other words, the liquid droplets can be easily and stably ejected onto the surfaces of the object <NUM>. By using this embodiment, it is not necessary to perform the plasma treatment, so that the damage to object can be reduced.

In the present embodiment, examples in which a step <NUM> is provided on the surface of the object <NUM> is described with reference to the drawings.

First, as shown in <FIG>, the first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> are moved and disposed on the object <NUM> having the step <NUM>. The step <NUM> (also referred to as a pattern or convex part) on the surface of the object <NUM> is provided as an organic insulating layer. The organic insulating layer used for the step <NUM> is not particularly limited. In this example, a polyimide resin is used for the step <NUM>. The organic insulating layer may be formed of other organic resin such as an acrylic resin or an epoxy resin, or an inorganic material. In this embodiment, the step <NUM> is provided in the shape of a grid (also referred to as a parallel cross structure) so as to expose a part of the surface on the object <NUM>. Each of the first region R1 and the second region R2 is surrounded by the step <NUM>.

In this case, the first liquid droplet ejection unit <NUM> is arranged on the first region R1. The first liquid droplet ejection unit <NUM> ejects the first liquid droplet <NUM> onto the first region R1 (more specifically, at a predetermined position within the first region R1). As shown in <FIG>, the first liquid droplets <NUM> are ejected onto the surfaces of the step <NUM> and the object <NUM>.

Next, the first liquid droplet ejection unit <NUM> moves from the first region R1 to the second region R2 on the object <NUM>. The second liquid droplet ejection unit <NUM> moves onto the first region R1 where the first liquid droplet <NUM> was ejected. In this case, the first liquid droplet <NUM> attempts to minimize the surface area by surface tension. When there is a region surrounded by such a parallel cross structure, the first liquid droplet <NUM> attempts to minimize the area of the interface with the air by retracting into the region. Further, the evaporation rate of the first liquid droplet <NUM> is faster as the thickness of the first liquid droplet <NUM> is thinner. Therefore, the first liquid droplet <NUM> of the region (inside of the parallel cross structure) surrounded by the step evaporates slowly, and the liquid on the step <NUM> dries quickly. Therefore, as shown in <FIG>, after a predetermined period of time has elapsed, the first liquid droplet <NUM> exists only in the region (inside of the parallel cross structure) surrounded by the step <NUM>. The first liquid droplet <NUM> is repelled from the step <NUM> in the first region R1 and remains only on the object <NUM>.

Similar to the first region R1, the first liquid droplet ejection unit <NUM> ejects the first liquid droplet <NUM> onto the second region R2 of the object <NUM>. The second liquid droplet ejection unit <NUM> ejects the second liquid droplet <NUM> onto the first region R1 in synchronized with the first liquid droplet ejection unit <NUM>. In this example, the second liquid droplet ejection unit <NUM> ejects the second liquid droplet at the same time as the first liquid droplet ejection unit <NUM> ejects the first liquid droplet. In this case, the second liquid droplet <NUM> may be ejected in the situation in which the first liquid droplet <NUM> remains on the surface of the first region R1 in the object <NUM>.

The first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> repeat the above-described process. As shown in <FIG>, the second droplets <NUM> are ejected not on the step <NUM>, but only on the surface of the object <NUM>.

In the present embodiment, when the second liquid droplet <NUM> is ejected, the first liquid droplet <NUM> remains only on the surface (specifically, inside the parallel cross structure) of the object <NUM>. This suppresses electrostatic charging on the object <NUM> and improves the wettability on the surface of the object <NUM>. Therefore, the second liquid droplet <NUM> is easily landed on the surface of the object <NUM> preferentially, and the second liquid droplet <NUM> can be stably ejected without being affected by the step <NUM>.

Also, when there is the first liquid droplet <NUM> having the conductive inside of the parallel cross structure, an electric field line is concentrated in the portion. This makes it easier for the second liquid droplet <NUM> (ink) to land on the inside of the parallel cross structure. That is, the second liquid droplet <NUM> can be ejected to a desired position.

From the above, by using the present embodiment, the electrostatic charging of the object itself is removed, and the effect of the step <NUM> applied to the object is alleviated. Thus, as shown in <FIG>, in the case in which the step <NUM> is provided on the surface of object <NUM>, the second liquid droplet <NUM> can be stably ejected and desired patterns can be formed. The first liquid droplet <NUM> may remain on the object <NUM> after patterning by the second liquid droplet <NUM>.

In the present embodiment, a liquid droplet ejection device differing from the first embodiment is described. Specifically, an example in which a liquid droplet ejection device includes a plurality of first liquid droplet nozzles <NUM> and a plurality of second liquid droplet nozzles <NUM> will be described. For the sake of explanation, members thereof is omitted as appropriate.

<FIG> is a schematic view of a liquid droplet ejection device 100A according to an embodiment of the present invention. The liquid droplet ejection device 100A includes the control unit <NUM>, the storage unit <NUM>, the power supply unit <NUM>, the driving unit <NUM>, a first liquid droplet ejection unit 140A, and a second liquid droplet ejection unit 150A.

In the present embodiment, a plurality of first liquid droplet ejection unit 140A are provided in direction (specifically, D3 direction orthogonal to the D1 direction) intersecting with respect to the direction (in this case, the D1 direction) in which the first liquid droplet ejection unit 140A moves (specifically, the first liquid droplet ejection unit 140A includes a first liquid droplet nozzle 141A-<NUM>, 141A-<NUM>, 141A-<NUM>, and 141A-<NUM>, each arranged independently). Similarly, a plurality of second liquid droplet ejection unit 150A are provided in direction intersecting with respect to the direction in which the first liquid droplet ejection unit 140A and the second liquid droplet ejection unit 150A move (more specifically, the second liquid droplet ejection unit 150A includes a second liquid droplet nozzle 151A-<NUM>, 151A-<NUM>, 151A-<NUM>, and 151A-<NUM>, each arranged independently). In the present embodiment, by having the first liquid droplet ejection unit 140A and the second liquid droplet ejection unit 150A, the process duration of the liquid droplet ejection can be shortened.

In the present embodiment, an example in which the plurality of first liquid droplet ejection unit 140A is shown, but the present invention is not limited thereto. The first liquid droplet ejection unit 140A does not need to have a precise positional accuracy, and thus may have different shape.

<FIG> is a schematic view of a liquid droplet ejection device 100B according to an embodiment of the present invention. In the liquid droplet ejection device 100B, a first liquid droplet nozzle 141B in a first liquid droplet ejection unit 140B may extend in a direction (specifically D3 direction) intersecting the direction in which the first liquid droplet ejection unit 140B moves (in this case D1 direction). Specifically, as shown in <FIG>, the first liquid droplet nozzle <NUM> may have a slit-shape. In this instance, the first liquid droplets <NUM> are ejected from the first liquid droplet nozzle <NUM> in a row. In this case, in the top view of patterns to be formed, as shown in <FIG>, the first liquid droplets <NUM> may be provided in a row, and the second liquid droplets <NUM> may be provided at predetermined positions apart from each other.

In the present embodiment, an example in which a plurality of second liquid droplet nozzle 151A are independently each provided in the second liquid droplet ejection unit <NUM> A is shown, but the present invention is not limited thereto. <FIG> is a top view of a second liquid droplet nozzle 151C. <FIG> is an enlarged top view and cross-sectional view of a part in the second liquid droplet nozzle 151C. As shown in <FIG> and <FIG>, the second liquid droplet nozzle 151C has a plurality of nozzle units 151Cb and plate units 151Cc. In this example, a plurality of nozzle units 151Cb are arranged in a row but may be arranged in a plurality of rows.

A metal material such as nickel is used for the nozzle unit 151Cb. The nozzle unit 151Cb is formed to be tapered by, for example, an electroforming process. A metal material such as stainless steel is used for the plate unit 151Cc. The plate unit 151Cc has a hole having an inner diameter r151 Cc larger than the inner diameter r151 Ca of the ejection port (nozzle tip 151Ca) in the nozzle unit 151Cb in a portion overlapping with the nozzle unit 151Cb. The nozzle unit 151Cb may be welded to the plate unit 151Cc or may be fixed by an adhesive. When the second liquid droplet nozzle 151C is used, a voltage may be applied to the nozzle 151Cb, or a voltage may be applied to the plate unit 151Cc (or the second ink tank <NUM>).

In the first embodiment of the present invention, an example in which the first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> move on the object <NUM> by the driving unit <NUM> is shown, but the present invention is not limited thereto. For example, in the liquid droplet ejection device, the driving unit <NUM> may move the object <NUM>. In this instance, the first liquid droplet ejection unit <NUM> and the second liquid droplet ejection unit <NUM> may be fixed in the same position.

In the first embodiment of the present invention, an example in which the first liquid droplet nozzle <NUM> is provided perpendicularly to the surface of the object <NUM> is shown, but the present invention is not limited thereto. The first liquid droplet nozzle <NUM> may have an inclination with respect to the direction perpendicular to the object <NUM>. The same applies to the second liquid droplet nozzle <NUM> of the second liquid droplet ejection unit <NUM>.

In the first embodiment of the present invention, an example has been shown in which a material having volatility is used for the first liquid droplet <NUM>, but the present invention is not limited thereto. For example, an antistatic agent may be used for the first liquid droplet <NUM>. In this case, it is desirable that the surface resistance value of the first liquid droplet <NUM> is <NUM><NUM> Ω / sq or more and <NUM><NUM> Ω / sq or less. The antistatic agent may not have volatility and may remain partially on the surface of the object <NUM>.

In the first embodiment of the present invention, an example in which the organic insulating layer is used as a step is shown, but the present invention is not limited thereto. For example, the step may be a wiring pattern, or an inorganic material may be used as the step. The object <NUM> itself may be processed to provide a step. The object <NUM> may be a wiring substrate in which wiring is laminated.

When the second liquid droplet <NUM> is ejected in the first embodiment of the present invention, an image may be taken by using an imaging device. In this instance, the imaging result may be determined by the control unit <NUM>. When the control unit <NUM> determines that there is an ejection failure, the control unit <NUM> may eject the first liquid droplet <NUM> and the second liquid droplet <NUM> again on the failure occurrence region. As a result, it is possible to suppress the liquid droplet ejection failure.

In the first embodiment of the present invention, an example has been described in which the first liquid droplet and the second liquid droplet are simultaneously ejected when the first liquid droplet and the second liquid droplet are synchronously ejected, but the present invention is not limited thereto. For example, the first liquid droplet and the second liquid droplet may not be ejected simultaneously, but the second liquid droplet may be ejected after the first liquid droplet has been ejected and a predetermined period of time elapsed. The first liquid droplet and the second liquid droplet may be ejected in conjunction with each other.

Claim 1:
A liquid droplet ejection device (<NUM>) comprising:
at least one first liquid droplet ejection unit (<NUM>) including a first liquid holding unit and a first nozzle tip (<NUM>, 141a), the first liquid holding unit configured to hold a first liquid, and the first nozzle tip configured to eject the first liquid in the first liquid holding unit as a first liquid droplet onto an object (<NUM>);
at least one second liquid droplet ejection unit (<NUM>) including a second liquid holding unit and a second nozzle tip (<NUM>, 151a), the second liquid holding unit configured to hold a second liquid, and the second nozzle tip configured to eject the second liquid in the second liquid holding unit as a second liquid droplet differing from the first liquid droplet onto the object;
an object holding unit (<NUM>) configured to hold the object; and
a driving unit (<NUM>) configured to move the first nozzle tip and the second nozzle tip in a first direction (D1) relative to the object holding unit, wherein
the first nozzle tip is arranged at a distance (L) in the first direction relative to the second nozzle tip and the liquid droplet ejection device is configured so that the second droplet is ejected in a first area where the first droplet was ejected when the second nozzle tip is moved by the distance (L), wherein
an inner diameter of the first nozzle tip in the at least one first liquid droplet ejection unit is larger than an inner diameter of the second nozzle tip in the at least one second liquid droplet ejection unit,
the at least one first liquid droplet ejection unit has a piezo type nozzle head,
the at least one second liquid droplet ejection unit has an electrostatic ejection type nozzle head,
the first liquid droplet has conductivity so as to remove static electricity from the surface of the object, and
the second liquid droplet contains a material for forming a pattern on the surface of the object.