JP2000301716A - Ink jet recording head and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the resistance of seal liquid when ink is ejected while eliminating generation of crosstalk. SOLUTION: The ink jet recording head 10 comprises a seal liquid sectioning means 24 made partially or entirely of a porous material 26, an ink ejection opening 12 provided in an ink jet plane 28, an ejection chamber 16 provided with an ink ejection means 14, and a section 18 for holding seal liquid 22. The seal liquid sectioning means 24 sections the seal liquid 22 discontinuously. According to the arrangement, the seal liquid 22 has no adverse effect on ink ejection and ink can be ejected stably while preventing generation of crosstalk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head and an ink jet recording apparatus, and more particularly, to an ink jet recording head and an ink jet recording apparatus for sealing an ink discharge port for discharging ink with a sealing liquid.

[0002]

2. Description of the Related Art In a conventional ink jet recording apparatus, it is a major 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 evaporation of the ink solvent. In a commercially available ink jet recording apparatus, at the time of non-printing or during a long period of non-operation, the nozzle is shielded from outside air by a capping means made of resin or the like to delay the drying of the ink. However, this capping means
In order to more effectively increase the airtightness of the nozzle, complicated procedures and devices are required. Also, with this capping means, the nozzle cannot be completely shielded from the air, and during storage, the drying and thickening of the ink inside the nozzle gradually progress, which may cause nozzle clogging. is there.

[0003] In a commercially available ink jet recording apparatus, various maintenance operations are required in order to eliminate nozzle clogging due to long-term suspension. For example, if the clogging of the nozzle is eliminated by vacuum operation that pulls out the clogging inside the nozzle from the outside of the nozzle by negative pressure, a pump and a waste ink absorber are required in the device, which makes the device complicated and large. , Increasing the cost of the equipment. Further, since the nozzle surfaces are collectively made to have a negative pressure, a large amount of ink is also sucked out from nozzles where no clogging occurs and discarded, thereby increasing running costs. In addition, in the case where nozzle clogging is eliminated by repeating the dummy jet operation and the wiping operation, a mechanism for moving the head to the maintenance position or pressing a member such as a blade against the head surface and performing a sliding motion is required. For example, the equipment becomes complicated and the cost increases. After long-term suspension of the inkjet recording device, these operations are combined before printing to perform maintenance operations, and waiting time before printing and noise due to maintenance operations also occur,
Is disadvantageous to users.

As means for avoiding the problem caused by clogging after a long period of suspension, as disclosed in Japanese Patent Application Laid-Open No. 52-104130, a film of a seal liquid insoluble in ink and a film of the seal liquid are provided. There is known a method in which the ink discharge port is sealed by means to shield the ink from the air and prevent the ink from drying.

Japanese Patent Application Laid-Open No. 49-115548 discloses that a seal liquid and a wetting mechanism seal an ink discharge port when the printing apparatus is not operating, and a seal liquid supply path is provided by a switch provided in a seal liquid supply path during operation. A method for stopping the supply of the water is described.

However, these methods have a disadvantage that the resistance of ink discharge is high at the start of discharge because the seal liquid is separated on the surface but is substantially continuous with the surrounding seal liquid inside. are doing. When the temperature of the environment in which the printing apparatus is used becomes low, the viscosity of the seal liquid may increase, and in the worst case, there is a problem that ink cannot be ejected.

If the seal liquid in front of the discharge port is substantially continuous with the seal liquid around the discharge port as described above, the behavior of the seal liquid that occurs at the time of ink discharge will reach the seal liquid in front of the adjacent discharge port. This causes ripples, which are affected when ink is ejected from the ejection openings, and causes a problem of so-called crosstalk, such as an unstable ejection direction.

Japanese Patent Application Laid-Open No. 54-69436 discloses a method of forming and releasing a seal liquid film in order to improve the ejection stability of ink droplets in a sealing method using a seal liquid.

JP-A-5-177841 describes a method of sealing a nozzle with a seal liquid as necessary, and a method of opening and closing a seal with a seal liquid in conjunction with carriage scanning.

However, in either method, switching between the state sealed by the seal liquid and the state released from the seal requires an external force such as opening and closing by a pump, an electromagnet, and a support, which complicates the structure of the head. This leads to an increase in the size of the printing apparatus.

[0011]

As described above, in the conventional method of sealing a nozzle with a sealing liquid, the worst case is when the sealing liquid has a high resistance at the time of discharge and the viscosity of the sealing liquid increases due to an environment change. The case (1) has a disadvantage that ink cannot be ejected.

In general, many non-volatile liquids having a low vapor pressure have a high kinematic viscosity due to a large molecular weight. Therefore, it is desirable to select a seal liquid having a high kinematic viscosity in order to make the seal liquid non-volatile for a longer period of time and maintain the sealing performance against clogging. Therefore, in order to adopt a specification that prevents clogging for a longer period of time, a sealing liquid having a high kinematic viscosity must be used, or the thickness of the sealing liquid must be increased, and the discharge resistance further increases. As a result, it becomes difficult to achieve both clogging prevention performance and discharge performance.

Further, at the time of ink discharge, the movement of the seal liquid accompanying the ink discharge propagates to the seal liquid near the adjacent ink discharge port where the seal liquid is continuous, and when the ink is discharged from this ink discharge port. It has a drawback of so-called crosstalk, which makes the ejection direction unstable and results in poor printing.

If a means for opening and closing the seal of the seal liquid is provided to avoid these problems, the apparatus becomes complicated and large.

The present invention has been made in view of the above-mentioned problems of the prior art.
An object of the present invention is to provide an ink jet recording head and an ink jet recording apparatus capable of reducing the resistance of a seal liquid at the time of ink ejection. Another object of the present invention is to provide an ink jet recording head and an ink jet recording apparatus capable of eliminating the occurrence of crosstalk by preventing the behavior of the seal liquid at the time of ink ejection from propagating to the surrounding seal liquid.

[0016]

According to the first aspect of the present invention, there is provided an ink discharge port for discharging ink, a seal liquid capable of sealing the ink discharge port, and a seal liquid for previously holding the seal liquid. A holding unit, an ink ejection unit that ejects ink from the ink ejection port in accordance with the input image signal, and the seal liquid in the vicinity of the ink ejection port and the seal liquid of the seal liquid holding unit discontinuously. A sealing liquid partitioning means for partitioning the sealing liquid, a part of which is in contact with the sealing liquid of the sealing liquid holding part and another part is exposed inside the sealing liquid holding part, and at least one of the sealing liquid partitioning means is provided. And a porous member constituting a part thereof.

Accordingly, since the ink discharge port is sealed by the seal liquid inside the seal liquid partitioning means (near the ink discharge port), drying of the ink is prevented. When the amount of the seal liquid near the ink discharge port decreases due to ink discharge or the like, the seal liquid moves from the seal liquid holding unit through the porous member, so that the necessary and sufficient seal liquid always exists near the ink discharge port. I do.

The seal liquid is partitioned by the seal liquid partitioning means so as to be discontinuous at a portion near the ink discharge port and at a portion of the seal liquid holding portion. For this reason, the resistance of the seal liquid at the time of ink ejection is reduced. In other words, in a configuration in which the discharge port is sealed without being partitioned such that the seal liquid is discontinuous, when the ink discharge unit attempts to discharge ink from the ink discharge port, the viscosity of the seal liquid is reduced. For example, not only the seal liquid near the ink discharge port but also the seal liquid around the ink discharge port tries to prevent ink discharge. On the other hand, in the present invention, the seal liquid is partitioned by the seal liquid partitioning means so as to be discontinuous. Therefore, when ink is to be discharged from the ink discharge port, the seal liquid at the ink discharge port discharges the ink. There is no influence of obstruction, and ink can be ejected stably.
In particular, even when the viscosity of the sealing liquid increases due to a change in environment or the like, the ink can be reliably ejected.

In addition, since the resistance of the seal liquid at the time of ink ejection is reduced in this manner, a seal liquid having a high kinematic viscosity can be used. Thereby, the sealing liquid becomes non-volatile for a long period of time, and the sealing performance against clogging can be maintained.

Further, since the seal liquid is partitioned by the seal liquid partitioning means so as to be discontinuous at the portion near the ink discharge port and at the portion of the seal liquid holding portion, the seal accompanying the ink discharge is formed. The movement of the liquid is attenuated as it propagates to the surroundings or substantially ceases to propagate. Thereby, occurrence of crosstalk is prevented.

In the present invention, "partitioning so as to be discontinuous" means that even if the seal liquid located in the vicinity of the ink ejection port is deformed by some external force or the like, the motion of the seal liquid caused by the deformation is propagated. Is attenuated (preferably does not substantially propagate). Therefore, if such conditions are satisfied, there is no need to completely separate the sealing liquid. When completely separated,
Since it becomes difficult to supply the sealing liquid inside the sealing liquid partitioning means and a new device is required for the supply, etc., the present invention keeps the discontinuity from this viewpoint while maintaining the discontinuity. At least a part of the sealing liquid partitioning means is constituted by a porous member into which the sealing liquid can flow.

According to a second aspect of the present invention, in the first aspect of the present invention, the porous member is made of a material having higher wettability to the seal liquid than to the ink. It is characterized by.

That is, the sealing liquid is more absorbed by the porous member than the ink. For this reason, it is possible to prevent the ink from adhering to the pores of the porous member or to block the pores, and the supply of the sealing liquid is not reduced.

According to a third aspect of the present invention, there is provided an ink jet recording head according to the first or second aspect.

Therefore, also in this ink jet recording apparatus, the effect of preventing the seal liquid from being discharged by the seal liquid partitioning means is eliminated, and the ink can be stably discharged. Further, by using a sealing liquid having a high kinematic viscosity, the sealing performance against clogging can be maintained. Further, occurrence of crosstalk is prevented. Thus, the ink jet recording apparatus has a small and simple configuration, and the degree of freedom in designing with respect to a specification for preventing long-term clogging is increased.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show a basic configuration example of the ink jet recording head 10 of the present embodiment. The ink jet recording head 10 of the present embodiment (hereinafter, may be simply referred to as “head 10”) has a sealing liquid partitioning means 24 formed in a substantially cylindrical shape by a porous member 26.
(Hereinafter, it may be simply referred to as "partition means 24"),
An ink ejection port 12 provided on an ink ejection surface 28, an ejection chamber 16 provided with an ink ejection means 14, and a seal liquid holding section 18 in which a seal liquid 22 is stored.
The ink 20 is supplied to the head 10 through an ink tank and an ink supply path (both not shown) outside the head 10 by an action caused by, for example, a capillary force or a pressure difference.

FIGS. 1 and 2 show one ink ejection port 12.
Although only the ink ejection port 12 is shown in FIG.
May be provided in plurality. In the drawings, for convenience, the ink discharge ports 12 are arranged in an upward direction, but the ink discharge direction, that is, the arrangement direction of the recording head 10 can be appropriately selected as desired. Is ejected in the direction of gravity (downward).

The ink discharging means 14 usable in the present embodiment includes ink discharging means used in a conventional ink jet recording head, for example, a pressurizing method.
Ink jetting means such as a continuous flow method and an electrostatic suction method can be widely used, and a method of concentrating acoustic waves, pressure waves, and the like can also be used. A thermal ink jet system or a piezoelectric system can be used as a pressurizing system discharging unit.

The seal liquid 22 usable in the present embodiment has a function of sealing the ink ejection port 12 and shielding the ink 20 of the ink ejection port 12 from air. The seal liquid 22 that maintains such a function contains at least a component insoluble in the ink 20, is incompatible with the ink 20, and does not spontaneously emulsify with the ink 20.

In order for the sealing liquid 22 and the ink 20 to be incompatible, specifically, the solubility of the sealing liquid 22 in the ink 20 depends on the head 10 or the ink jet recording apparatus ( Hereinafter, it may be simply referred to as a “recording device”).

Further, it is preferable that the sealing liquid 22 is non-volatile because it does not evaporate while the head 10 is at rest, and the sealing state of the discharge port 12 by the sealing liquid 22 does not change. Non-volatile refers specifically to a vapor pressure of 0.1 mmHg or less under an environment in which the head 10 or the recording device is used.

The sealing liquid 22 that can be used in the present embodiment
The kinematic viscosity of the ink is controlled by setting a period for preventing clogging,
It is possible to appropriately select the design specifications such as the diameter of the ejection port 12, the ejection frequency of the recording head 10, the film thickness of the seal liquid 22, the method of disposing the seal liquid 22, and the kinematic viscosity is changed from a low viscosity to a high viscosity. Can be widely used. However, in general, many non-volatile liquids having a low vapor pressure have a high kinematic viscosity due to a large molecular weight. For this reason, it is desirable to select a sealing liquid having a high kinematic viscosity in order to maintain the sealing performance against clogging by making the sealing liquid 22 non-volatile for a longer period of time. Is considered, the kinematic viscosity of the sealing liquid 22 in the environment where the head 10 or the recording device is used is 1 to 200 mm ² / s.
Is desirable.

The surface tension of the sealing liquid 22 which can be suitably used in the present embodiment is in the range of 15 to 70 mN / m under the environment where the head 10 or the recording apparatus is used. In order for the sealing liquid 22 to wet the surface of the ink, it is preferably 50 mN / m or less, and more preferably less than the surface tension of the ink 20 to be used.

A liquid originally suitable for these properties may be used alone, or a plurality of materials may be mixed to adjust the viscosity and surface tension to a preferred range before use.

Sealing liquid 2 when using water-based ink
As 2, organic solvents and oils that are liquid at room temperature can be used. For example, octane, nonane, tetradecane, hydrocarbons such as dodecane, oleic acid, higher fatty acids such as linoleic acid, n-decanol, water-insoluble alcohols such as dimethylbutanol, dibutyl phthalate,
A plasticizer such as dibutyl maleate can be used. Alternatively, vegetable oil, mineral oil, silicone oil, fluorine oil and the like can be used. These may be used alone or in combination of two or more as long as they can be mixed uniformly.

Before the start of printing, the sealing liquid 22 is
The liquid is supplied to the seal liquid holding unit 18 by a method such as application with a cloth or a blade. In this case, the supply of the sealing liquid 22 may be manual or automatic. Further, a mechanism may be provided in which a tube or a porous member is arranged near the seal liquid holding unit 18 and the seal liquid 22 is supplied to the seal liquid holding unit 18 by capillary force, surface tension, pressure difference, or the like. .
The sealing liquid 22 supplied to the sealing liquid holding section 18 by these methods flows into the partitioning means 24 through the porous member 26 of the sealing liquid partitioning means 24, and seals the surface of the ink 20 at the ink discharge port 12. A film of the liquid 22 is formed.

In this embodiment, the ink ejection surface 28
The film thickness of the upper seal liquid 22 depends on the period during which the sealing performance is maintained, the diameter of the ejection means 14, the diameter of the ejection port 12, the recording head 10
Discharge frequency, kinematic viscosity of the seal liquid 22, seal liquid 2
2 can be set as appropriate for design specifications such as a method of arranging 2. However, considering the sealing performance against clogging and discharging with lower energy, it is preferably 1 μm or more and 200 μm or less. Seal liquid 2
The film thickness of No. 2 can be controlled, for example, by adjusting the supply amount of the sealing liquid 22 or by forming the peripheral portion of the recording head 10 or the like into a shape that regulates the holding amount of the sealing liquid 22.

The sealing liquid 22 may be provided in the ink jet recording head 10 in advance or may be supplied to the ink jet recording head 10 as needed.

The partitioning means 24 is arranged so that the seal liquid 22 on the front face of the ink discharge port located near the ink discharge port 12 and the surrounding seal liquid 22 (the seal liquid 22 of the seal liquid holding section 18) are discontinuous. It is installed to partition into. In FIGS. 1 and 2, the partitioning means 24 is entirely formed of a porous member 26, and the porous member 26 has pores through which the sealing liquid 22 can flow. The shape of the partitioning means 24 is not limited to the illustrated substantially cylindrical shape as long as the partitioning means 24 can partition the sealing liquid 22 so as to be discontinuous. For example, it may be formed in a polygonal cylindrical shape, or may be a cylindrical shape having different cross sections in the height direction. Further, the shape need not necessarily be cylindrical.

The sealing liquid holding section 18 is provided with a partitioning means 24.
And a seal (hereinafter, sometimes referred to as “inside of the partitioning means 24”) in front of the ink discharge port 12 and surrounded by the inner wall of the partitioning means 24 along with the ink discharge. When the liquid 22 decreases, the porous member 26
This is a place where the sealing liquid 22 is held so that the sealing liquid 22 flows into the partitioning means 24 through the pores. The size of the seal liquid holding portion 18 is not particularly limited as long as the seal liquid holding portion 18 is provided on the side opposite to the inside of the partition means 24 with the partition means 24 interposed therebetween. As shown in FIGS. When the area outside the partitioning means 24 on the surface 28 is used as the seal liquid holding portion 18, the outer wall of the partitioning means 24 and the ink discharge surface 28 can be shared as a part of the seal liquid holding portion 18, so that the production becomes easy and preferable. . Further, if a device capable of supplying the sealing liquid 22 from the outside to the sealing liquid holding unit 18 is further added, the amount of the sealing liquid 22 that can be held by the sealing liquid holding unit 18 can be reduced. Is more preferable because the sealing liquid 22 can be supplied from outside.

Further, one seal liquid holding portion 18 may be provided for each of the ink discharge ports 12,
It is preferable to provide one seal liquid holding portion 18 for a plurality of ink ejection ports 12 because the structure of the head 10 is simplified.

The height of the partition means 24 may be any height as long as the seal liquid 22 can be partitioned "in a discontinuous manner" between the inside and the outside of the partition means 24. It may be the same as or slightly wider than the discharge port 12. The thickness of the partitioning means 24 is not particularly limited. For example, in addition to FIGS. 1 and 2, as shown in FIGS. 3 and 4, a structure common to the partitioning means 24 corresponding to the adjacent ink ejection port 12 may be used.
This is preferable because it is not necessary to consider the thickness of the material and the processing is facilitated. As shown in FIG. 5, a seal liquid cover 30 may be provided in order to prevent foreign matter from entering the seal liquid holding unit 18 or the like. Further, each partition means 24 does not need to be in contact with the ink ejection surface 28, and may be provided on another supporting member such as the seal liquid cover 30.

The partitioning means 24 partitions at least a part thereof (all in the embodiment shown in FIG. 1) of the porous member 26 so as to partition the sealing liquid 22 so as to be discontinuous. And at the portion of the porous member 26 from the sealing liquid holding portion 18 to the partitioning means 2
4 can be supplied with the sealing liquid 22. This constitutes a part of the partitioning means 24,
The pores of the porous member 26 that connects the inside and the outside of the liquid are sufficiently thin and long, so that the
2 has a large resistance to the flow propagation, and the flow can be almost stopped.
When the sealing liquid 22 is exhausted inside the partition member 24, the partitioning means 24 is closed by the capillary force of the pores of the porous member 26.
This is because the property of absorbing the external sealing liquid 22 and supplying it to the inside can be compatible. Furthermore, since it is a porous material (a material having pores), it can serve as a filter for preventing dust and the like mixed in the sealing liquid 22 from entering the sealing liquid holding portion 18. .

The porosity required for the porous member 26 used in the present embodiment is a resistance that reduces the flow of the seal liquid 22 due to the ink discharge at the time of ink discharge, and the seal liquid holding part due to the capillary force at the time of supply. Any porous material having pores communicating with the inside and outside of the partitioning means 24 so that the sealing liquid 22 can flow from 18 may be used. The size of the sealing liquid 22 and the partitioning means 24 to be changed, the porous member 26
Therefore, an optimal combination may be appropriately selected, but preferably, the average diameter of the pores is 20n.
m to 1 mm, and the void ratio of the porous portion is 1
When it is 0% or more and 70% or more, the balance between the reduction of the crosstalk and the resupply of the seal liquid 22 is improved. Further, in recent years, the density of ink discharge ports, which are increased in density, for example, the diameter of the discharge ports is 10 μm to 50 μm, and the distance between adjacent discharge ports is about several tens to several hundreds dpi, the average diameter of the pores is 0.1 μm. It is more preferably between 1 μm and 20 μm, and the porosity ratio of the porous portion is 2 from the balance between the strength of the porous member 26 and the resupply speed.
5% or more and 50% or less are more preferable.

The portion made of the porous member 26 may be the entirety of the sealing liquid partitioning means 24 or a part thereof, but the sealing liquid 22 is supplied to the sealing liquid holding section 1.
8, at least a part of the porous member 26 comes into contact with the sealing liquid 22 of the sealing liquid holding portion 18 and the porous member 26
Must be exposed inside the sealing liquid partitioning means 24. Therefore, as shown in FIGS. 1, 3 and 5, the entirety of the sealing liquid partitioning means 24 is made of the porous member 2.
6, but in addition to this, FIGS. 4, 6 (A), (B), FIGS. 7, 8 (A), (B),
(C) As shown in FIG. 9, the porous member 26 may constitute a part of the partitioning means or may be further divided into a plurality of parts. In the drawings, the porous member 26 located in the sealing liquid 22 is not shown with a dot pattern indicating that it is porous,
Except for those shown in FIGS. 7 and 9, a porous member 26 is provided over the entire area in the height direction of the sealing liquid partitioning means 24 (in other words, at the same height as the sealing liquid partitioning means 24). Regardless of the configuration, the porous member 26
Are partially in contact with the sealing liquid 22 in the sealing liquid holding part 18 and the other part is the partitioning means 2.
4, the sealing liquid can be supplied through these portions. In particular, the porous member 26
If the portion of the porous member 26 is configured to be large or the number of portions of the porous member 26 is increased, even if a part of the porous member 26 is blocked (A portion that is not closed) or another porous member 26, the sealing liquid 22 can be supplied, and the larger area increases the supply speed, which is more preferable. As described above, it is preferable that there are two or more porous portions, and it is more preferable that the plurality of porous portions are located far apart from each other, since they will not be blocked at once by large dust. preferable. For the same reason, it is more preferable that even if there is only one porous portion, the porous portion is configured to expand in the circumferential direction of the partition means 24 as shown in FIG.

When a part of the partitioning means 24 is constituted by the porous member 26, the intermediate portion in the height direction of the sealing liquid partitioning means 24 is constituted by the porous member 26 as shown in FIG. With such a structure, the partitioning means 24 can be formed by laminating the sheet of the porous member 26 and the other material sheets of the partitioning means 24. In addition, the thickness of the porous member 26 does not need to be the same as the thickness of the wall of the sealing liquid partitioning means 24, as shown in FIG.
As shown in (A), (B) and (C), the wall of the sealing liquid partitioning means 24 may be thinner. With such a configuration, the supply speed of the sealing liquid 22 can be increased. Further, the portion made of the porous member 26 does not necessarily have to penetrate the partitioning means 24 in the thickness direction, and is provided only on the upper surface of the partitioning means 24 as shown in FIG. If one end is in contact with the seal liquid 22 of the seal liquid holding unit 18 and the other end is exposed inside the ink discharge port 12 side of the seal liquid partition unit 24, the seal liquid partition unit is separated from the seal liquid holding unit 18 by capillary force. The seal liquid 22 can be supplied to the inside of the seal liquid 24. With such a configuration, only the surface of the partitioning means 24 needs to be made porous (in other words, first, the cylindrical sealing liquid partitioning means 24 is formed, and the porous member 26 is attached to the upper surface thereof. This is preferable because the sealing liquid partitioning means 24, which is entirely made of a porous material, is stronger and more durable, and since different materials can be combined, the design latitude is also widened.

As a material and a processing method used in this embodiment, when the porous member 26 is used for the entire partitioning means 24 (that is, when the partitioning means 24 is entirely composed of the porous member 26), Seals made of polyolefin resin, fluorine polymer resin, polysulfone resin, polyester resin, polyamide resin, polyimide resin, polyurethane resin, polyacryl resin, polystyrene resin, polyketone resin, silicone resin, etc. Various porous resins with pore distribution that allows liquid to pass through, or metals such as nickel, tantalum, titanium, platinum, copper, Cu-Sn, Fe-Cr-Ni, Cu-Sn-Pb, Fe -
Various sintered metal materials such as alloys such as C, Fe-Cu, Fe-C-Cu, Al-Cu, etc. Various porous ceramics, such as porous silica, porous magnesia, and porous alumina, which are sintered by selecting a particle diameter so as to have a pore distribution, can be used.

As the processing method, various fine processing techniques such as various dry etching, electric discharge processing, laser processing and mechanical processing can be used depending on the material. Further, the above-mentioned raw materials may be formed into desired partitioning means by using various types of foam molding, sinter molding, and print molding. In particular, a material having a property that the wettability of the sealing liquid is greater than the wettability of the ink, such as porous PTF
If E is used, even if the ink 20 adheres, it becomes easy to be replaced with the sealing liquid 22, and it is possible to prevent the adhesion or clogging of the ink to the porous material portion from obstructing the supply of the sealing liquid. The effect also increases, and it is suitable as a material.

In order to make the porous member 26 a part or only the surface of the partitioning means 24, a technique for imparting porosity by various modification treatments may be used. In this case, as materials, stainless steel, nickel, aluminum, platinum,
Various metals such as gold, cobalt, titanium, copper, iron, polyolefin resin, fluoropolymer resin, polysulfone resin, polyester resin, diacetate resin, triacetate resin, polyacrylic resin, polyurethane resin, polycarbonate Resin, polyvinyl chloride resin, polyamide resin, polyimide resin, polystyrene resin, polyketone resin, silicone resin and other various resins, silica, alumina, magnesia silica and other ceramics, and silicon used as a semiconductor material Various inorganic compounds such as may be used alone or in combination, various etching and electric discharge machining, various fine processing techniques such as laser processing and mechanical processing, and after forming into a desired shape by sintering molding or printing, etc., Modification treatment appropriate for the material where necessary It can be created by choosing a.

As the modification treatment method, an anodization method, a modification treatment by irradiation with an energy beam such as a laser, an electron beam, an X-ray, or an ultraviolet ray, and a modification treatment with a solvent can be used. Further, in addition to providing such a porous property, a porous material and other materials may be used in combination.

The printing operation in this embodiment will be described. By the ink ejection, part or all of the sealing liquid 22 inside the partitioning means 24 flies together with the ink 20, and the inside of the partitioning means 24 is in a state where the seal liquid 22 is small or no. After the ink 20 flies, the sealing liquid 22 held by the sealing liquid holding unit 18 is filled with the porous member 2 constituting a part or all of the partitioning means 24.
6 and flows into the partitioning means 24. When the ink is not continuously ejected, the flowing sealing liquid 22 seals the ink 20 in the ink ejection port 12 again to prevent clogging.

The ink jet recording apparatus according to the present embodiment is an ink jet recording apparatus including the ink jet recording head 10 according to the present embodiment. With this ink jet recording apparatus, an image corresponding to an image signal is ejected onto an image recording medium to record an image. By incorporating the inkjet recording head 10 of the present embodiment, the inkjet recording apparatus of the present embodiment can reduce or omit a maintenance step such as a vacuum, which is conventionally required, thereby simplifying the entire apparatus and simplifying the apparatus. Can be downsized.

According to the present embodiment, the seal liquid 22 near the discharge port 12 is replaced with the seal liquid 22 around the discharge port 12.
In this state, the resistance during ejection can be reduced. For this reason, even in a low-temperature environment where the viscosity of the sealing liquid 22 increases, a discharge image does not occur and a clear image can be printed.

Further, since the discharge resistance is low, even if the seal liquid 22 to be disposed is thickened or a high-viscosity seal liquid material is selected, both the performance against the clogging and the discharge performance can be achieved, and the discharge performance can be maintained for a longer period of time. A head design that prevents clogging is also possible.

Further, since the seal liquid 22 is partitioned so as to be discontinuous, even if the seal liquid 22 on the front face of the ink discharge port 12 moves violently due to ink discharge, the seal liquid on the front face of the adjacent ink discharge port 12 can be obtained. It does not affect the liquid 22 and eliminates printing defects due to crosstalk.

Further, by providing the porous member 26 which constitutes a part or the whole of the sealing liquid partitioning means 24, after the sealing liquid 22 inside the partitioning means 24 decreases due to the ink ejection, the sealing liquid holding part 18 The sealing liquid 22 can be supplied through the pores of the porous member 26 without the need for another device.

Further, since the portion for supplying the sealing liquid 22 from the sealing liquid holding section 18 to the inside of the partitioning means 24 is constituted by the porous member 26, the sealing liquid holding section 18 is separated from the partitioning means 24. It is possible to suppress intrusion of dust and the like into the inside of the ink ejection port, and to reduce printing defects due to dust and the like adhering to the ink ejection port 12.

In the present embodiment, the sealing liquid 22
Because the discharge port 12 is sealed, the clogging due to drying of the ink 20 does not occur even after a long period of suspension, so that the discharge operation can be performed immediately when necessary, and the maintenance process after the long period of suspension is reduced. Alternatively, it can be omitted. This makes it possible to reduce the size and cost of the ink jet recording apparatus, reduce the waiting time before printing and the noise caused by maintenance, which have been caused by maintenance after a long pause, and reduce the running cost associated with large amounts of ink disposal. Can be suppressed.

[0060]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

As shown in FIGS. 10 and 11, the head 1
Reference numeral 0 denotes a discharge chamber 16 in which a discharge means 14 is disposed, and a discharge port 12 having a diameter of 40 μm
The partitioning means 24 and the seal liquid holding unit 18 are provided around the ejection port 12 on the ink ejection surface 28. Further, the partitioning means 24 is entirely composed of a porous member 26.

The sealing liquid 22 is a liquid prepared by mixing a plurality of types of silicone oils (kinematic viscosity 30 mm ²
/ S, surface tension 20.8 mN / m, specific gravity 1.0). The vapor pressure of this sealing liquid 22 at 25 ° C. is 0.1 m
mHg or less, and there was no compatibility with the used ink 20.

The ink 20 used was composed of 60% by weight of water, 38% by weight of diethylene glycol, and 2% by weight of a dye, and had a kinematic viscosity of 2.0 mm ² / s and a surface tension of 40 mN / s.
m, specific gravity 1.06.

The discharge means 14 is a thermal ink jet type discharge means, and is constituted by providing a heater on the wall surface of the discharge chamber 16. The heater is configured by laminating a protective layer made of tantalum on a heating element layer made of polycrystalline silicon. The heater is wired so that a predetermined signal is applied to the heater at a timing corresponding to the image signal by a signal applying unit (not shown).

The partitioning means 24 coats a 25 μm-thick PTFE film on a stainless steel plate prepared as a discharge surface, and uses a photoresist to have an inner diameter of 50 μm and an outer diameter of 9 μm.
A cylindrical PTFE member having a thickness of 0 μm and a height of 25 μm was formed. This member was modified into porous PTFE having an average pore diameter of 1.0 μm by irradiating the member with argon plasma particles, and partitioning means 24 as a whole was formed of a porous member. Thereafter, an ink ejection port was formed in the stainless steel plate by excimer laser irradiation to form an ink ejection surface 28 on which the partitioning means 24 were arranged, and the recording head 10 was bonded to a member having the ejection means 14. Further, the outside of the partitioning means 24 on the ink ejection surface 28 was used as the seal liquid holding unit 18.

Using the head 10 of this embodiment, the state of ejection was observed under magnification. Seal liquid holding section 1 of head 10
8, the sealing liquid 22 is supplied to the inside of the partitioning means 24 by the inflow through the pores of the porous member 26 so as to have a thickness of 20 μm.
m of seal liquid 22 was placed. In this state, the discharging means 1
When a voltage of 15 V was applied to the heater No. 4 in the form of a pulse in a time period of 6 μs to eject the ink 20, it was observed that the ink droplets were ejected stably. After the discharge, the seal liquid 22 flows into the partitioning means 24 through the pores of the porous member 26, the seal liquid 22 returns to the initial state, and the seal liquid 22 around the discharge port 12 Was sealed.

Under these conditions, the head 10 of this embodiment is attached to a recording apparatus having a mechanism for feeding recording paper, and an image is printed in a room at normal temperature (25 ° C. and 50% relative humidity), and the image is printed. Observation of the resulting image with the naked eye revealed that there was no print defect such as blurring and a clear image was recorded.

Further, this recording apparatus is used in a low-temperature environment (temperature
(C, 30% relative humidity) for 24 hours, and a printing test was performed in this low-temperature environment. As a result, clear printing was possible as in the previous test. Observation of the printed image with the naked eye revealed no difference from the printing test at room temperature, and a clear image was recorded.

Further, the ink jet recording head 1
0 was left for 30 days in an environment at a temperature of 25 ° C. and a relative humidity of 30% RH, and then a print test was performed without performing any ordinary maintenance operation of the ink jet recording apparatus to observe an output image. No ejection failure due to clogging occurred in the ink ejection port 12, and the printed image had no disturbance of dots, and a clear image was recorded as before leaving. A print test was performed after leaving a head similar to the recording head 10 of the present embodiment under the same conditions for 30 days except that the seal liquid 22 was not disposed, and clogging occurred in more than half of the discharge ports. And could only be partially printed.

For comparison, a head similar to the head of this embodiment except that the partitioning means 24 and the seal liquid holding portion 18 were not installed was used, and the seal liquid 22 was arranged on the ink discharge surface 28 where the discharge ports 12 are lined up. Was arranged in a film shape so as to have a thickness of 20 μm. In order to observe the ejection of the head and to obtain the same ejection as the head 10 of the embodiment, it was necessary to adjust the ejection unit so that a voltage of 16 V was applied for 7 μs. This is the partition means 24
It is considered that the reason for this is that the resistance during ink ejection is increased due to the absence of the ink, and a larger ejection energy is required than in the embodiment of the present invention. That is, in the example, it can be seen that the ink 20 can be ejected with lower energy.

Further, when this head was attached to a recording apparatus and an image print test was performed in a room at room temperature (air temperature: 25 ° C., relative humidity: 50%), a dot position of a level that could be recognized by the naked eye was found in some parts. Printing failure due to variation occurred. Therefore, when the flight observation of the ink ejection was performed, it was found that this variation was caused by the cross talk of the seal liquid accompanying the ink ejection from the adjacent ink ejection port. Further, when a printing test was performed in a low-temperature environment (temperature 5 ° C., relative humidity 30%) for 24 hours after performing the printing test in this low-temperature environment, defective portions where no printing was performed were conspicuous, and only an unclear image was obtained. Was.

[0072]

According to the present invention, an ink discharge port for discharging ink, a seal liquid capable of sealing the ink discharge port, a seal liquid holding section for holding the seal liquid in advance, and an image signal inputted An ink discharge unit that discharges ink from the ink discharge port in accordance with (a), a seal liquid partitioning unit that partitions the seal liquid in the vicinity of the ink discharge port and the seal liquid of the seal liquid holding unit so as to be discontinuous. A porous member provided so that a part thereof comes into contact with the sealing liquid of the sealing liquid holding part and another part is exposed inside the sealing liquid holding part, and constitutes at least a part of the sealing liquid partitioning means. Therefore, when ink is to be ejected from the ink ejection port, the effect of the seal liquid at the ink ejection port preventing the ink ejection is affected. No longer, it is possible to discharge a stable ink, without the propagation behavior of the sealing liquid at the time of ink discharge to the surrounding seal liquid, it is possible to eliminate the occurrence of crosstalk.

[Brief description of the drawings]

FIG. 1 shows a basic configuration of an ink jet recording head according to an embodiment, (A) is a plan view, and (B) is I of (A).
FIG. 2 is a sectional view taken along line I.

FIG. 2 is a perspective view corresponding to FIG. 1 and illustrating a basic configuration of an inkjet recording head according to an embodiment.

FIGS. 3A and 3B show another aspect of the ink jet recording head of one embodiment, wherein FIG. 3A is a plan view and FIG.
FIG. 2 is a sectional view taken along line I-II.

FIGS. 4A and 4B show still another mode of the ink jet recording head of one embodiment, wherein FIG. 4A is a plan view and FIG. 4B is a sectional view taken along line III-III of FIG.

FIGS. 5A and 5B show still another mode of the ink jet recording head of one embodiment, wherein FIG. 5A is a plan view and FIG. 5B is a cross-sectional view taken along line IV-IV of FIG.

FIGS. 6A and 6B are perspective views showing still another mode of the ink jet recording head of one embodiment.

FIG. 7 is a perspective view showing still another mode of the ink jet recording head of one embodiment.

FIGS. 8A to 8C are perspective views showing still another mode of the ink jet recording head of one embodiment.

FIGS. 9A and 9B show still another mode of the ink jet recording head according to one embodiment, wherein FIG. 9A is a plan view, FIG. 9B is a cross-sectional view taken along line VI-VI of FIG. It is a principal part expanded sectional view.

10A and 10B show an embodiment of the ink jet recording head of the present invention, wherein FIG. 10A is a plan view and FIG.
FIG. 7 is a sectional view taken along line VII.

FIG. 11 is a perspective view corresponding to FIG. 10 and illustrating an embodiment of the inkjet recording head of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ink jet recording head 12 Ink ejection port 14 Ink ejection means 18 Seal liquid holding part 22 Seal liquid 24 Seal liquid partition means 26 Porous member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasushi Suwabe 430 Nakaicho Sakai, Ashigara-gun, Kanagawa Green Tech Nakai Inside Fuji Xerox Co., Ltd. (72) Inventor Yuji Suemitsu 430 Sakai Nakaicho, Ashigarashimo-gun, Kanagawa Prefecture Inside Green Tech Nakajima Fuji Xerox Co., Ltd. (72) Inventor Megumi Hasebe 430 Sakai Nakaicho Sakaigami, Kanagawa Pref. Satoshi Mohri 430 Sakai, Kami-gun, Nakai-cho, Kanagawa Prefecture Green Tech Inside Fuji Xerox Co., Ltd. F term (reference) 2C056 EA01 EA04 EA17 FA02 JA24 2C057 AF04 AF34 AF74 BA04

Claims (3)

[Claims] An ink ejection port for ejecting ink; a seal liquid capable of sealing the ink ejection port; a seal liquid holding section for holding the seal liquid in advance; An ink discharge unit configured to discharge ink from an ink discharge port, a seal liquid partitioning unit configured to partition the seal liquid in the vicinity of the ink discharge port and the seal liquid of the seal liquid holding unit so as to be discontinuous, A porous member that is provided so as to be in contact with the sealing liquid of the sealing liquid holding portion and the other portion is exposed inside the sealing liquid holding portion, and that constitutes at least a part of the sealing liquid partitioning means. An ink jet recording head, characterized in that: 2. The ink jet recording head according to claim 1, wherein the porous member is made of a material having higher wettability with respect to the seal liquid than with the ink. 3. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.