JP3750375B2 - Ink jet recording head and ink jet recording apparatus including the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording head that discharges ink droplets stably and performs printing on an image recording medium, and an ink jet recording apparatus including the ink jet recording head.
[0002]
[Prior art]
As a typical inkjet recording method for performing printing by discharging droplets, particularly ink drops, onto a printing surface, there is a method using a nozzle. Conventionally, a recording method using the nozzle is continuous with an on-demand type. There is a flow type.
The on-demand type is a system that performs printing by ejecting ink intermittently from nozzles corresponding to recorded information, and representative examples include a piezoelectric element system and a thermal system.
The piezoelectric element method applies a pulse voltage to a piezoelectric element attached to an ink chamber to deform the piezoelectric element, thereby changing the ink hydraulic pressure in the ink chamber and ejecting an ink drop from a nozzle. Dots are recorded.
In the thermal method, ink is heated by a heating element provided in an ink chamber, and ink droplets are ejected from nozzles by bubbles generated thereby to record dots on recording paper.
On the other hand, the continuous flow type applies pressure to the ink to continuously eject the ink from the nozzles, and at the same time applies vibration by a piezo vibrator or the like to form a protruding ink column into droplets, which are further selective to the droplets. Recording is performed by charging and deflecting.
[0003]
In these ink jet recording apparatuses, it is a big problem to prevent nozzle clogging due to drying and thickening of ink during non-operation. Various ink materials have been developed to solve this problem, but it is still difficult to reduce the evaporation of the ink solvent.
In a commercially available inkjet recording apparatus, during non-printing or long-term rest, the nozzle and the outside air are shielded by a resin capping means or the like to delay the drying of the ink. However, this capping means requires a complicated procedure and apparatus in order to increase the airtight state in the nozzle more effectively. In addition, the capping means cannot completely shield the inside of the nozzle from the air, and the ink inside the nozzle is gradually dried and thickened during storage, resulting in nozzle clogging. is there. As described above, in practice, in a commercially available inkjet recording apparatus, various maintenance operations are required to recover clogging of nozzles due to a long-term pause.
[0004]
As means for avoiding problems caused by clogging after a long pause, as disclosed in JP-A-52-104130, by means of a sealing liquid insoluble in ink and means for stretching a film of the sealing liquid, Means are known in which the ink discharge port is sealed to shield the ink from the air to prevent the ink from drying. However, this method has been found to have the following drawbacks. That is, the above method has a fundamental problem that the state of the sealing liquid changes every time ink is ejected, and as a result, ink ejection is not stable and the print image quality is deteriorated. Hereinafter, the disadvantages of the known prior art will be described with reference to the drawings.
[0005]
FIG. 7 shows a change in the state of the sealing liquid in a conventional inkjet recording head that employs a sealing method using a sealing liquid. FIG. 7A shows an example of the timing of the ink discharge request signal (image signal) to the ink discharge port of the ink jet recording head. (B) schematically shows a change in the sealing state corresponding to (a) of an ink jet recording head adopting a sealing method by a conventional liquid seal. In general, when an image is printed by an inkjet recording apparatus, an ink droplet ejection request signal is sent to one ink ejection port at various timings. For example, the request signal may be sent in an extremely short period similar to the period of the highest pixelation frequency that the recording head has, or conversely, the request signal may not be sent for several seconds. is there. The ink ejection port is completely sealed when the request signal A is sent, but is not sealed when the request signal B is sent, and the request signals C and D are sent. When it has been in place, it is incompletely sealed. When request signals are sent at various timings as described above, the sealing state of the ink discharge ports by the sealing liquid is different, and thus the resistance when ink is discharged from the discharge ports is not constant. As a result, variations occur in the drop diameter of the ejected ink droplet and the flying speed of the ink droplet, and the print image quality is degraded. In order to avoid this, it is necessary to sufficiently reduce the period of the request signal for each ink discharge port, and as a result, the printing speed is greatly reduced.
[0006]
As another method that employs a sealing method using a sealing liquid, for example, Japanese Patent Laid-Open No. 49-115548 describes a method in which the supply of the sealing liquid is stopped during operation and only ink droplets are ejected during ejection. However, in this case, a switch for the sealing liquid supply path is required, and the structure of the print head becomes complicated. As a result, the entire printing apparatus becomes large or expensive.
[0007]
As described above, the conventional nozzle sealing method using a sealing liquid has low ink ejection stability, and as a result, the print image quality is degraded. On the other hand, in order to avoid this problem and ensure the stability of ink ejection, as described above, it is necessary to separately provide an opening / closing means using a seal liquid switch, which results in an increase in the size of the printing apparatus, In addition, it will be complicated. Therefore, a recording head that employs a sealing method using a sealing liquid does not have such a drawback, that is, a technique that can stably maintain ink ejection performance without using an additional device such as a switch. The reality is that it does not exist.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to solve the conventional problems and achieve the following objects. That is, according to the present invention, in a method of sealing a nozzle with a sealing liquid, an ink droplet to be ejected can be obtained by always maintaining the state of the sealing liquid at the time of ink ejection without using an additional device such as a switch. An object of the present invention is to provide an ink jet recording head capable of preventing nozzle clogging while keeping the size of the ink jet constant, and to provide an ink jet recording apparatus equipped with such an ink jet recording head .
[0009]
[Means for Solving the Problems]
Means for solving the above problems are as follows. That is,
<1> An ink discharge port, a seal liquid that seals the ink discharge port, an ink discharge unit that discharges ink in accordance with an image signal and releases the seal of the ink discharge port during ink discharge, and the restoration of the seal The seal restoring means, and the ink ejection means does not eject ink when restoring the seal, but exposes the ink to the ink ejection port so as to contact the seal liquid, thereby restoring the seal. An inkjet recording head characterized by also serving as a means.
<2> The inkjet recording according to <1>, wherein the seal restoration unit restores the seal by bringing the ink exposed to the ink discharge port into contact with the seal liquid in a state where the seal of the ink discharge port is released. Head.
<3> an ink discharge port, an ink discharge unit that discharges ink in accordance with an image signal, and that unseals the ink discharge port with a seal liquid when ink is discharged; and a seal restoration unit that restores the seal The ink ejecting means also serves as the seal restoring means by exposing the ink to the ink ejection port so as to contact the seal liquid without ejecting ink when restoring the seal. Inkjet recording head.
<4> Conveying means for conveying an image recording medium, an ink jet recording head for recording an image by discharging ink to the image recording medium conveyed by the conveying means, and inputting an image signal to the ink jet recording head An inkjet recording apparatus comprising an image signal input unit, wherein the inkjet recording head is the inkjet recording head according to any one of <1> to <3>.
[0010]
According to the seal restoration means, it is possible to positively restore the film by the seal liquid to the initial state with respect to the seal liquid in which the seal of the ink discharge port is released by the discharge of the ink droplet, and the drying of the ink Prevention and stabilization of ink ejection performance can be achieved.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
[Inkjet recording head]
Reference examples regarding the ink jet recording head of the present invention will be described with reference to the drawings.
As shown in FIG. 1, a reference example relating to the ink jet recording head of the present invention includes an ink discharge port 3, a seal liquid 4 that seals the ink discharge port 3, an ink discharge according to an image signal, and an ink discharge. It is configured by including an ink discharge means 7 for unsealing the ink discharge port 3 and a seal restoration means 14 for restoring the seal.
The seal restoration means positively restores the film made of the seal liquid to the initial state with respect to the seal liquid in a state where the ink discharge port is unsealed by discharging the ink droplets. As such a seal restoring means, it is preferable to restore the seal by bringing the ink exposed to the ink discharge port into contact with the seal liquid in a state where the seal of the ink discharge port is released.
[0012]
The ink jet recording head of the present invention, as shown in FIGS. 2 and 4, the ink ejection means 7, also serves as the sealing restoring means. This eliminates the need for providing the seal restoration means separately, and has features such as cost reduction of the inkjet recording head, ease of production, and high density of the ink discharge ports.
In addition, the ink jet recording head of the present invention may be an embodiment in which the sealing liquid 4 is not used as a constituent element. In that case, when the user supplies the sealing liquid 4 later when using the ink jet recording head. Good.
[0013]
(Ink ejection port)
Next, the ink ejection port will be described with reference to FIG.
The ink discharge port 3 communicates with an ink chamber 13 provided in the lower part of the ink jet recording head 1 via an ink flow path. The ink chamber 13 and the ink flow path are supplied with ink 5 from an ink supply means (not shown) and filled with the ink 5 by an action caused by a capillary action or a pressure difference, for example.
[0014]
When the ink discharge port 3 is not in the ink discharge state, it is sealed with the sealing liquid 4, so that the ink 5 exposed to the ink discharge port 3 is not in contact with air. The ink discharge means 7 provided on the bottom surface of the ink chamber 13 applies pressure or the like to the ink 5 filled in the ink flow path according to the image signal, and discharges ink droplets from the ink discharge port 3.
[0015]
(Ink ejection means)
Next, an ink discharge unit that discharges ink from the ink discharge port according to the image signal will be described.
As the ink discharge means usable in the present invention, any of the ink discharge means used in the ink jet recording head according to the prior art may be used. For example, a thermal ink jet method, a piezoelectric element method (for example, a piezo vibrator type) And the like.
In the thermal ink jet method, a device having a heating function is used as an ink discharge means, and the ink in the ink flow path leading to the ink chamber or the ink chamber is heated according to the image signal, and the volatile components contained in the ink are instantaneously removed. Bubbles are generated by evaporation, and ink is ejected at a pressure associated with the volume change.
In the piezoelectric element method, a member having a piezoelectric element is used as an ink discharge means, and a member capable of propagating deformation of the piezoelectric element is used on the wall surface of the ink chamber or the wall surface of the ink flow path leading to the ink chamber. An electric field is applied to the piezoelectric element in accordance with an image signal, the wall member of the ink flow path is deformed by the resulting distortion of the piezoelectric element, and the ink is ejected by applying pressure to the ink by the resulting pressure wave.
In FIG. 1, the ink discharge means 7 is disposed on the bottom surface of the ink chamber 13, but is not limited thereto, and may be disposed on the side surface of the ink flow path, for example.
[0016]
(Seal liquid)
Next, the seal liquid used for preventing the ink inside the ink discharge port from drying will be described.
The seal liquid that can be used in the present invention has a function of sealing the ink discharge port and shielding the ink exposed to the ink discharge port from the air. The sealing liquid that maintains such a function contains at least a component insoluble in the ink, is incompatible with the ink, and does not spontaneously emulsify with the ink.
In order for the sealing liquid and the ink to be incompatible, specifically, the solubility of the sealing liquid in the ink is preferably 0.1% by weight or less at room temperature (25 ° C.). Further, it is preferable that the seal liquid is non-volatile at room temperature because it does not evaporate while the head is at rest and the seal state of the ink discharge port by the seal liquid does not change. In addition, it is non-volatile at normal temperature specifically, that vapor pressure is 0.1 mmHg or less at 25 degreeC.
[0017]
The kinematic viscosity of the sealing liquid which can be used in the present invention is in the range of 1 to 100 mm ² / s, it is desirable to reduce the resistance for discharge or less 50 mm ² / s. Further, the surface tension of the sealing liquid that can be used in the present invention can be used as long as it is in the range of 15 to 70 mN / m. However, it is desirable that the surface tension be 50 mN / m or less in order to progress to the surface of the ink. It is desirable that the surface tension of the ink to be smaller than. Of course, any liquid suitable for these properties can be used, but a plurality of materials can be mixed to adjust the viscosity and surface tension.
[0018]
As the sealing liquid in the case of using water-based ink, organic solvents and oils that are liquid at room temperature can be used.
For example, hydrocarbons such as octane, nonane, tetradecane and dodecane, higher fatty acids such as oleic acid and linoleic acid, water-insoluble alcohols such as n-decanol and dimethylbutanol, plasticizers such as dibutyl phthalate and dibutyl maleate Can be used. Alternatively, vegetable oil, mineral oil, silicone oil, fluorine oil or the like can be used. These may be used alone or in combination of two or more.
[0019]
In the ink jet recording head of the present invention, the seal liquid 4 is arranged as shown in FIG. 3 so that the ink 5 exposed to the ink discharge port 3 does not come into contact with external air. As a result, moisture in the ink 5 does not evaporate, and troubles such as clogging of the ink discharge port 3 do not occur.
The seal liquid 4 is applied to a surface provided with the ink discharge port 3 (hereinafter referred to as an “ink discharge surface”) by liquid injection from a dropper or a tube, a brush, a cloth, or a blade before starting printing. It can be supplied by a method such as coating. Further, a mechanism may be provided in which a tube or a porous member is disposed in the vicinity of the ink discharge surface, and the seal liquid 4 is continuously supplied to the ink discharge surface by a capillary force, surface tension, pressure difference, or the like. The seal liquid 4 supplied to the ink discharge surface by these methods forms a film of the seal liquid 4 on the ink discharge surface.
[0020]
The seal liquid comes into contact with the ink exposed at the ink discharge port, but is not compatible with the ink and has a difference in surface tension from the ink, so that a film of the seal liquid is also formed on the ink surface. The thickness of the sealing film on the ink ejection surface can be selected as appropriate depending on the surface tension and viscosity of the ink, ejection means, nozzle diameter, storage period for preventing clogging, etc., but consider the sealing performance and ejection resistance against clogging. And it is preferable that it is 1-100 micrometers. The thickness of the seal film can be adjusted, for example, by making the supply amount of the seal liquid, the recording head peripheral portion, or the like into a shape that regulates the retention amount of the seal liquid.
[0021]
(Seal restoration means)
Next, the seal restoration means will be described with reference to FIGS.
FIG. 3 shows a mode in which the thermal ink discharge means 7 also serves as a seal restoration means. That is, using a heater having a heating function, the ink near the ink ejection means 7 in the ink flow path leading to the ink chamber 13 or the ink chamber is heated according to the seal restoration signal, and the volatile component contained in the ink 5 is removed. The ink 8 exposed to the ink discharge port 3 is applied to the seal liquid 4 in a state where the seal of the ink discharge port 3 is released using the pressure accompanying the volume change by instantaneously evaporating to generate bubbles 8. Contact is made (FIG. 2) to restore the seal.
FIG. 5 shows a mode in which the piezoelectric element (piezo vibrator) type ink discharge means 7 also serves as a seal restoration means. That is, a piezoelectric element is used, and a member capable of propagating the deformation of the piezoelectric element is used on the wall surface of the ink chamber 13 or the wall surface of the ink flow path leading to the ink chamber. An electric field is applied in accordance with the signal, the wall member of the ink flow path is deformed by the resultant distortion of the piezoelectric element, and the seal of the ink discharge port 3 is unsealed by the resulting pressure wave The ink 4 exposed to the ink discharge port 3 is brought into contact with the liquid 4 (FIG. 4) to restore the seal.
[0022]
The seal restoration means used in the present invention to restore the seal liquid on the nozzle plate with ink makes the ink exposed to the ink discharge port come into contact with the seal liquid in a state in which the seal of the ink discharge port is released. Any means can be used, and the configuration is not particularly limited.
In FIGS. 3 and 5, the ink discharge means also serves as the seal restoration means . However , in the present invention , as described above, a mechanism for merely bringing the ink into contact with the seal liquid that has been unwound at the outer edge of the ink discharge port is provided. In the configuration provided, the ink discharge means also serves as the seal restoring means because the manufacturing process of the ink jet recording head and the manufacturing cost of the ink jet recording head are likely to increase .
[0023]
The seal restoration means has a function of restoring the state in which the seal liquid completely seals the ink discharge port from the state in which the seal to the ink discharge port is released by ink discharge. If there is no seal restoration means in the inkjet recording head, the details of the cause of the time required for the seal liquid to restore from the unsealed state to the completely sealed state are currently analyzed Among them, the biggest factor may be that the seal liquid in an unsealed state is trapped around the ink discharge port. The ink discharge port generally forms a corner between the inner wall surface of the nozzle and the nozzle discharge surface. As a result, the periphery of the discharge port is easy to hold the seal liquid at a high contact angle due to its shape, and if the contact angle with the ink discharge surface is more acute due to burrs or the like, the seal liquid is trapped and the ink discharge port It is considered that the holding force to leave the exposed state is higher and higher.
The seal restoring means in the present invention makes it possible to eliminate the energy barrier against the progress of wetting of the sealing liquid by wetting the periphery of the ejection port with ink and bringing the ink into contact with the end of the sealing liquid.
[0024]
The signal for changing the meniscus shape of the ink may be any waveform such as a sine wave, a triangular wave, and a rectangular wave. The conditions such as the signal application time and the applied voltage are not strong enough to cause the ink inside the ink discharge port to be ejected as ink droplets for recording an image, but may be weak enough to make contact with the sealing liquid. There is no particular limitation.
[0025]
[Inkjet recording apparatus]
The ink jet recording head of the present invention having the above-described configuration is a conventional so-called ink jet recording apparatus, that is, a transport unit that transports an image recording medium, and ejects ink to the image recording medium transported by the transport unit. In an inkjet recording apparatus comprising an inkjet recording head for recording an image and an image signal input means for inputting an image signal to the inkjet recording head. An ink jet recording apparatus using the ink jet recording head of the present invention can print on an image recording medium by ejecting ink droplets stably.
In addition, the ink jet recording apparatus of the present invention can reduce or omit the maintenance process such as vacuum, which has been conventionally required, by incorporating the ink jet recording head according to the present invention.
[0026]
In the present invention, as shown in FIG. 1, from the viewpoint of briefly explaining each configuration, for the sake of convenience, a mode in which ink droplets are ejected from the bottom to the top has been shown. However, the present invention is not necessarily limited thereto. Even when ink droplets are ejected in the lateral direction or ink droplets are ejected from the top to the bottom, the effects of the present invention can be sufficiently exerted.
[0027]
【Example】
Examples of the present invention will be described below, but the present invention is not limited to these examples.
Example 1
In preparing the ink jet recording head according to this example, a liquid prepared by mixing a plurality of types of silicone oil as a sealing liquid on the nozzle plate (kinematic viscosity 30 mm ² / s, surface tension 20.8 mN / m, 25 ° C. A seal film having a thickness of about 15 μm was formed using a vapor pressure of 0.1 mmHg or less and no compatibility with ink.
Next, as shown in FIG. 3, an ink jet recording head 1 in which the thermal ink discharge means 7 was used as the ink discharge means 7 and the ink discharge means 7 also served as a seal restoration means was manufactured.
The ink jet recording head was incorporated into an ink jet recording head evaluation experimental machine, and the following test was performed. The ink used was a commercially available inkjet ink. The ink used is a water-based ink comprising 60% by weight of water, 38% by weight of diethylene glycol and 2% by weight of a dye, having a viscosity (viscosity coefficient) of 2.0 mPa · s, a surface tension of 40 mN / m, and a specific gravity of 1.06.
[0028]
First, as shown in FIG. 8, when ink droplets were continuously ejected from the ink ejection port 3, the ink ejection port 3 was unsealed (FIG. 9).
Next, as shown in FIG. 2, the seal restoration is performed such that the ink, which is exposed to the ink discharge port 3, is brought into contact with the seal liquid 4, which is unwrapped at the outer edge of the ink discharge port, with respect to the heater as the ink discharge unit 7 A signal (signal application time: several tens of μs or less, applied voltage: applied voltage of about 50% during ink ejection) was input. The ink 5 comes into contact with the seal liquid 4, and immediately after that, the ink 5 begins to get wet to the ink surface of the ink discharge port 3, and finally the seal liquid 4 covers the surface of the ink 5 (the seal shown in FIG. 3 is closed). State).
[0029]
FIG. 6A schematically shows the state of the seal when the seal restoration signal 10 is input from the state where the ink is unwound at the outer edge of the ink discharge port. As described above, when the seal restoration signal 10 is input, it is possible to arbitrarily restore the seal. Therefore, the time (t ₁ ) from when the seal is released by discharge until the seal is restored and completely closed is shortened. At the same time, the sealing liquid is closed at the next discharge, and it is possible to discharge stably every time a print request signal is generated. When a restoration signal was input, the time (t ₁ ) from when the seal was released by discharge until the seal was restored and completely closed was 80 μs, which was shorter than 100 μs, which is one cycle of the maximum drive frequency.
[0030]
(Comparative Example 1)
In Example 1, an ink jet recording head was produced in the same manner as Example 1 except that the seal restoration means was not provided.
Using this ink jet recording head, as shown in FIG. 8, the ink droplets are continuously ejected from the ink ejection port 3, and the behavior of the seal liquid 4 is observed when left in this state as shown in FIG. did.
As a result, as shown in FIG. 6B, the sealing liquid 4 keeps the state unwound at the outer edge of the ink ejection port 3 due to the surface tension of the sealing liquid 4 itself and the balance of wetting with the nozzle plate 2. After a while, it was confirmed that the sealing film was closed. This time (t ₁ ′) was 400 μs, which is five times that when the restoration signal is not used. If ink is discharged after waiting for the sealing film to naturally close in this way, there is a problem that the printing speed cannot be increased.
As described above, by providing the seal film restoration means, it is possible to arbitrarily restore the seal at the ink discharge port, so the seal liquid state is closed during the next printing, and at what timing the print request signal is generated. Even in this case, the discharge can be stabilized.
[0031]
(Example 2)
In preparing the ink jet recording head according to this example, a liquid prepared by mixing a plurality of types of silicone oil as a sealing liquid on the nozzle plate (kinematic viscosity 30 mm ² / s, surface tension 20.8 mN / m, 25 ° C. A seal film having a thickness of about 20 μm was formed using a vapor pressure of 0.1 mmHg or less and no compatibility with ink.
Next, as shown in FIG. 5, an ink jet recording head 1 in which the ink ejecting means 7 of a piezo vibrator was used as the ink ejecting means 7 and the ink ejecting means 7 also served as a seal restoring means was manufactured.
The ink jet recording head was incorporated into an ink jet recording head evaluation experimental machine, and the following test was performed. The ink used was a commercially available inkjet ink. The ink used is a water-based ink comprising 60% by weight of water, 38% by weight of diethylene glycol and 2% by weight of a dye, having a viscosity (viscosity coefficient) of 2.0 mPa · s, a surface tension of 40 mN / m, and a specific gravity of 1.06.
[0032]
First, as shown in FIG. 8, when ink droplets were continuously ejected from the ink ejection port 3, the ink ejection port 3 was unsealed (FIG. 9).
Next, as shown in FIG. 4, the ink 5 exposed to the ink discharge port 3 is brought into contact with the sealing liquid 4 unwrapped at the outer edge of the ink discharge port with respect to the piezo vibrator as the ink discharge means 7. A seal restoration signal (signal application time: several tens of μs or less, applied voltage: applied voltage of about 50% during ink ejection) was input. As a result, the seal liquid 4 that has been unsealed begins to cover the surface of the ink 5, and finally returns to the state in which the seal liquid 4 covers the surface of the ink 5 (the state in which the seal shown in FIG. 5 is closed). It was.
[0033]
Also in this embodiment, as shown in FIG. 6A, when the seal restoration signal 10 is input, the seal can be restored arbitrarily, so that the seal is restored after the seal is released by discharge. The time until complete closing (t ₁ ) is shortened, and the sealing liquid is closed at the next discharge, so that it is possible to discharge stably every time a print request signal is generated. It was. When a restoration signal was input, the time (t ₁ ) from when the seal was released by discharge until the seal was restored and completely closed was 90 μs, which was shorter than 100 μs, which is one cycle of the maximum drive frequency.
[0034]
(Comparative Example 2)
In Example 2, an ink jet recording head was produced in the same manner as in Example 2 except that the seal restoration means was not provided.
Using this ink jet recording head, as shown in FIG. 8, the ink droplets are continuously ejected from the ink ejection port 3, and the behavior of the seal liquid 4 is observed when left in this state as shown in FIG. did.
As a result, as shown in FIG. 6B, the sealing liquid 4 keeps the state unwound at the outer edge of the ink ejection port 3 due to the surface tension of the sealing liquid 4 itself and the balance of wetting with the nozzle plate 2. After a while, it was confirmed that the sealing film was closed. This time (t ₁ ′) was 400 μs, which is about 4.5 times that when the restoration signal is not used. If ink is discharged after waiting for the sealing film to naturally close in this way, there is a problem that the printing speed cannot be increased.
As described above, by providing the seal film restoration means, it is possible to arbitrarily restore the seal at the ink discharge port, so the seal liquid state is closed during the next printing, and at what timing the print request signal is generated. Even in this case, the discharge can be stabilized.
[0035]
【The invention's effect】
According to the present invention, it is possible to arbitrarily restore the seal of the seal liquid in a state where the ink discharge port is unsealed by the ink droplet ejection by the seal restoration means. Therefore, according to the present invention, it is possible to provide an ink jet recording head that achieves both nozzle clogging and stabilization of printing speed without using an additional device such as a switch or an opening / closing means using external force.
In addition, the ink jet recording apparatus of the present invention incorporating the ink jet recording head can reduce or omit maintenance steps such as vacuum, which have been essential in the past.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a basic configuration of a reference example relating to an ink jet recording head of the present invention.
FIG. 2 is an example of a sectional view of a nozzle plate showing a seal restoring means of the ink jet recording head of the present invention.
FIG. 3 is another example of a cross-sectional view of a nozzle plate showing the seal restoring means of the ink jet recording head of the present invention.
FIG. 4 is another example of a sectional view of a nozzle plate showing a seal restoring means of the ink jet recording head of the present invention.
FIG. 5 is another example of a sectional view of a nozzle plate showing a seal restoring means of the ink jet recording head of the present invention.
FIG. 6A is a diagram showing a correspondence relationship between the seal restoration signal and the state of the seal liquid. FIG. 6B is a diagram illustrating a state of the seal liquid when the seal restoration signal is not input.
FIG. 7A is a diagram schematically showing an example of image signal input timing, and FIG. 7B is a diagram showing a conventional sealed liquid sealing type inkjet recording head. It is a schematic diagram which shows the state change of the sealing liquid when an image signal is input at the timing shown to a).
FIG. 8 is an example of a cross-sectional view of a nozzle plate showing a state where an ink discharge port is unsealed by ink droplet discharge.
FIG. 9 is another example of a cross-sectional view of a nozzle plate showing a state in which an ink discharge port is unsealed by ink droplet discharge.
FIG. 10 is a perspective view of a nozzle plate showing a state in which an ink discharge port is unsealed by ink droplet discharge.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inkjet recording head 2 Nozzle plate 3 Ink ejection port 4 Seal liquid 5 Ink 6 Ink droplet 7 Ink ejection means 8 Air bubble 9 Ink ejection signal 10 Seal restoration signal 11 Recording paper 12 Substrate 13 Ink chamber 14 Seal restoration means

Claims (3)

An ink discharge port, a seal liquid that seals the ink discharge port, an ink discharge unit that discharges ink in accordance with an image signal and releases the seal of the ink discharge port when ink is discharged, and a seal restoration that restores the seal And the ink ejecting means also serves as the seal restoring means by exposing the ink to the ink ejection port so as to contact the seal liquid without ejecting ink when restoring the seal. An ink jet recording head. An ink discharge port, an ink discharge unit that discharges ink in accordance with an image signal, and that unseals the ink discharge port with a seal liquid when ink is discharged; and a seal restoration unit that restores the seal. An ink jet recording head characterized in that the ejection unit also serves as the seal restoration unit by exposing the ink to the ink ejection port so as to contact the seal liquid without ejecting ink when restoring the seal. .   Conveying means for conveying an image recording medium, an ink jet recording head for recording an image by discharging ink to the image recording medium conveyed by the conveying means, and an image signal input for inputting an image signal to the ink jet recording head An inkjet recording apparatus comprising: the inkjet recording apparatus according to claim 1, wherein the inkjet recording head is the inkjet recording head according to claim 1.

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