JP2004122500A - Liquid communication structure for interconnecting liquid containing section and liquid using section, and liquid supply system and ink jet recorder employing the liquid communication structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a liquid (ink) supply system having a closed structure for an ink jet recording head in which a gas causing a trouble to recording operation and liquid supply operation can be removed quickly and smoothly from a liquid supply passage without causing any complication of the structure, and the arrangement of the ink tank is simplified while reducing the cost by utilizing the performance for removing the gas to the ink tank. <P>SOLUTION: Fluid connection is established between an ink tank 10 and a supply section 50 for introducing ink from the ink tank to a recording head 20 through two interconnecting passages 53 and 54. Under a state where gas exists in the supply section, ink is moved from the ink tank 10 through one interconnecting passage 53 and gas is transferred to the ink tank 10 through the other interconnecting passage 54. Furthermore, a mechanism for introducing outer air is provided on the ink supply passage side in order to sustain a preferable negative pressure state in the ink supply system. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention, for example, supplies a liquid such as ink to a recording head or a pen as a liquid using unit from an ink tank or the like as a liquid storing unit without waste and stably, and further includes a gas existing in the liquid using unit. The present invention relates to a liquid communication structure for discharging liquid into a liquid storage unit, a liquid supply system using the same, and an ink jet recording apparatus using the system.
[0002]
[Prior art]
A liquid using apparatus, for example, an ink jet recording apparatus that forms an image on a recording medium by applying a liquid ink to the recording medium using an ink jet recording head has a relatively small noise at the time of recording and a small dot. Since it can be formed at a high density, it is used in many printings including color printing in recent years. As one form of such an ink jet recording apparatus, an ink jet recording head that receives supply of ink from an ink tank attached inseparably or separably, and a recording head mounted with the recording head in a predetermined direction with respect to a recording medium. A carriage for relatively scanning, and a conveying unit for relatively conveying (sub-scanning) the recording medium relative to the recording head in a direction orthogonal to the predetermined direction, and ejecting ink during a main scanning process of the recording head. In some cases, recording is performed by causing Furthermore, a recording head capable of discharging black ink and each color ink such as yellow, cyan, magenta, etc. is mounted on the carriage, and not only monochrome printing of a text image with black ink, but also changing the discharge ratio of each ink. Some have enabled full-color printing.
[0003]
In such an ink jet recording apparatus, it is problematic to appropriately discharge gas such as air that has entered or is entering the ink supply path.
[0004]
Here, the gas entering the supply system is roughly classified into four types of generation factors.
1) those that enter from the ink discharge port of the print head or are generated by the discharge operation;
2) gas dissolved inside the ink is separated,
3) those that enter by gas permeation from the outside through the material constituting the supply path, and
4) What comes in when replacing the ink tank in the form of a cartridge,
It is.
[0005]
By the way, the ink flow path formed in the ink jet recording head is very fine, and therefore the ink supplied from the ink tank to the recording head is in a clean state in which foreign matter such as dust is not mixed. Is required. That is, in the case where foreign matter such as dust is mixed in, there is a problem that the foreign matter is clogged in a particularly narrow discharge port or a liquid path portion directly communicating with the ink flow path in the recording head. It may not be possible to perform a proper ink ejection operation, and it may be impossible to recover the function of the recording head.
[0006]
Therefore, in general, a filter member for removing foreign matter is arranged in an ink flow path between the print head and an ink supply needle protruding into the ink tank, and the filter member can prevent foreign matter from entering the print head. Often configured.
[0007]
On the other hand, in recent years, in order to realize high-speed printing, the number of ejection ports for ejecting ink has been increasing, and a drive signal applied to an element that generates energy for ejecting ink also has an increasingly higher frequency. Things are being adopted. For this reason, the consumption amount of ink per unit time is also rapidly increasing.
[0008]
Accordingly, the amount of ink passing through the filter member naturally increases, but in order to reduce the pressure loss due to the filter member, it is effective to partially expand the supply path and arrange a large-area filter member. is there. For this reason, if air bubbles are mixed in the supply path, the air bubbles are likely to stay in the space on the upstream side of the filter member in the enlarged portion and cannot be discharged, which causes a problem that the smooth supply of ink is hindered. . Further, the gas accumulated inside the supply path may become fine bubbles and mix into the ink guided to the ejection port, which may cause problems such as non-ejection of the ink.
[0009]
Therefore, it is highly desirable that the air remaining in the ink supply path be quickly removed, and there are several methods for that purpose.
[0010]
One of them is to perform a cleaning operation as described below.
The ink jet recording head performs printing by, for example, ejecting a liquid ink as a droplet from an ejection port arranged opposite to a recording medium, so that the ink viscosity increases due to evaporation of the ink solvent from the ejection port. Solidification of the ink, adhesion of dust to the discharge port, and mixing of bubbles into the liquid path inside the discharge port may cause clogging or the like of the discharge port, resulting in poor printing.
[0011]
For this reason, in the ink jet recording apparatus, a capping means for covering the discharge port of the recording head during the non-printing operation and the surface of the recording head having the discharge port (discharge port forming surface) are cleaned as necessary. A wiping member is provided. The capping means not only functions as a lid for preventing drying of the ink of the above-described ejection port when printing is stopped, but also when the ejection port is clogged, covers the ejection port forming surface with a cap member, for example, By applying a negative pressure by a suction pump communicating with the inside of the cap member, the ink is sucked and discharged from the discharge port to cause clogging due to solidification of the ink in the discharge port, and ink discharge due to thickened ink or mixed bubbles in the liquid path. It also has a function to eliminate defects.
[0012]
The forcible ejection of ink to eliminate these ink ejection failures is also referred to as a cleaning operation, which is performed when printing is restarted after a long period of suspension of the apparatus, or when the quality of a recorded image is deteriorated by a user. This process is performed when the cleaning switch is operated upon recognizing that the ink is forcibly discharged, and is a process that involves a wiping operation of the ejection port forming surface by a wiping member formed of an elastic plate such as rubber after the ink is forcibly discharged. .
[0013]
Then, at the time of initial filling for filling ink into the flow path or liquid path of the recording head for the first time, or at the time of a cleaning operation performed when the ink tank is replaced, a suction pump is applied to the capped discharge port forming surface. Attempts have been made to apply a large negative pressure by driving the ink at a high speed, thereby obtaining a high flow velocity in the ink supply path to discharge the retained bubbles.
[0014]
However, the problem of the increase in the area of the filter member for suppressing the dynamic pressure of the filter member and the problem with the residual air bubbles are based on incompatible effects, and it is extremely difficult to remove the residual air bubbles from the discharge port side with a suction pump. Have difficulty. In other words, as a condition for bubbles to pass through the filter due to the flow of ink by the suction pump, a predetermined flow rate is required for the ink passing through the filter. To generate this, a large pressure difference must not be generated on both sides of the filter. Not be. To realize this, it is usually considered to reduce the filter area to increase the flow path resistance or to increase the flow rate of the suction pump. However, if the filter is reduced, the supply performance to the head is impaired, and If the gas is to be removed at a flow rate, a large amount of ink is discharged, and the ink is unnecessarily consumed.
[0015]
Therefore, two other methods of removing bubbles are considered: a method of directly discharging the air to the outside, and a method of moving the ink to the ink tank side and keeping the ink at a site in the tank which does not hinder the ink supply. Of these, the former has a configuration in which a communication port to the outside is provided in the supply path, but this is not a preferable method for the following reasons.
[0016]
That is, in an ordinary ink jet recording apparatus, a capillary force generating member such as an absorber is provided in an ink tank or a flexible ink storage is provided in order to prevent undesired leakage of ink from an ejection port. In many cases, a negative pressure is generated in the ink storage space of the ink tank by arranging an elastic member such as a spring on the bag and applying a biasing force in the direction of expanding the internal volume. In such a case, if a simple communication port is arranged in the supply path for removing bubbles, the negative pressure will be released due to the intrusion of air from the communication port. This is because it is necessary to provide a pressure adjusting valve and the like, and the structure of the ink supply system and the structure of the recording apparatus using the ink supply system become complicated and large. Also, in order to prevent ink from leaking from the communication port for discharging air bubbles, it is necessary to provide a water-repellent film or the like that allows gas to pass but not liquid, or the communication port only when bubbles remain. This is because a device (such as a bubble amount detection mechanism or a communication port opening / closing mechanism) that opens and discharges air is required, and this increases the manufacturing cost and the complexity and size of the structure.
[0017]
On the other hand, consider moving bubbles to the ink tank side. At this time, if the amount of ink corresponding to the volume of the bubbles moving to the ink tank can be transferred to the head side, there is no change in the volume of the ink tank, and the generated negative pressure is kept constant, and the ejection port is discharged to the recording head. This is preferable because a negative pressure balanced with the holding force of the meniscus formed on the surface can be applied. Further, if the ink tank is of a cartridge type, it can be replaced with a new one when the remaining amount of ink to be stored is exhausted, so that it can be said that the configuration can completely remove gas from the ink supply system. .
[0018]
Here, in order to smoothly transfer the gas to the ink tank side, the upstream portion of the filter member in the enlarged portion is formed, for example, in a tapered shape further upstream, that is, the ink supply from the ink supply needle. It is also considered effective to form the passage so that it does not suddenly expand toward the position where the filter member is provided.
[0019]
However, in an ink jet recording apparatus widely used for consumer use, an ink tank in the form of a cartridge containing black ink and color ink can be detachably mounted to a recording head or a carriage on which the recording head is mounted. In many cases, for example, the ink cartridge is configured such that a hollow ink supply needle mounted upward on a carriage is inserted into the ink cartridge so that ink can be supplied to the recording head. Therefore, the diameter of the ink supply needle connecting the ink cartridge and the recording head becomes a problem. In other words, a thin supply needle is required in order to simplify the operation of mounting the cartridge. However, in the case of a thin tube, the meniscus force is increased, so that bubbles cannot be moved smoothly.
[0020]
By the way, some proposals have been made on a mechanism for moving gas to the ink tank side.
[0021]
For example, in Patent Document 1, the recording head side is divided into a first chamber having an air communication port and a second chamber having a capillary force generating member, and the first chamber and the ink tank are opened on the first chamber side. There is disclosed a configuration in which air is supplied from one of the communication paths to the ink tank side by connecting two or more communication paths having different heights. In such a configuration, a negative pressure is applied to the head by a head difference between the first chamber and the second chamber, or a capillary force generating member disposed in the second chamber, and an air communication port is provided in the first chamber. Can be arranged.
[0022]
However, the configuration of Patent Literature 1 aims to introduce the atmosphere in accordance with the ink supply in order to use up the ink in the ink tank that does not deform, and to eliminate bubbles remaining in the ink supply path. Not something. In particular, the first chamber serving as the ink supply path is open to the atmosphere through the atmosphere communication port, so that no negative pressure is generated. The first chamber is always in contact with the atmosphere, and a predetermined negative pressure is applied to the head as in the present application. Therefore, unlike a system in which the ink storage unit and the ink supply unit are substantially sealed, there is no recognition of the problem of gas mixing peculiar to the sealed supply system. That is, the technique disclosed in the above document cannot be applied to transfer the gas from the ink supply path, particularly from the second chamber or the recording head side, to the ink tank.
[0023]
Further, as another proposal, in Patent Document 2, when the negative pressure generating member storage chamber and the liquid storage chamber are made separable, a gas priority introduction path and a liquid discharge path are arranged in a communication part connecting the two. In addition, a configuration has been disclosed in which gas can be reliably introduced. However, this document also discloses a configuration in which a capillary force generating member and an air communication port are arranged between the ink tank and the recording head. Is an ink supply path of an open-to-atmosphere system that freely enters and exits, and the technique disclosed in the document cannot be applied even from the viewpoint of eliminating bubbles remaining in the ink supply path peculiar to a closed system.
[0024]
Further, Patent Document 3 discloses an ink container (ink container 50) having a liquid outlet pipe (drain conduit 66, 72, 74) and a gas inlet pipe (vent conduit 76, 82, 84) projecting downward. The liquid outlet pipe has an upper opening on the bottom surface of the inner wall of the storage container, and the gas outlet pipe has an opening disposed inside the storage space of the storage container. An object of the technique disclosed in the document is a configuration of a system for refilling ink in a member (14) having reservoirs (16, 18, 20), using an ink supply path or ink downstream of the reservoir. It is not intended to remove air bubbles remaining in the portion where the air bubbles are generated. Also, it is considered that if a meniscus is formed in the liquid outlet pipe and the gas inlet pipe since the lower opening heights thereof are equal to each other, the liquid or gas cannot move. Further, since there is no communication port for communicating the inside of the ink container and the member 14 with the atmosphere and there is no element for adjusting the negative pressure, the negative pressure inside the ink rapidly increases as the use of the ink is continued. This is based on the principle that the ink cannot be supplied to the portion where ink is used.
[0025]
Further, in Patent Document 4, a replenishment tank for replenishing ink with a reservoir tank having a negative pressure generating member storage chamber and an ink storage chamber can be connected, and an upper part and a lower part of a space of the ink storage chamber are provided. When the replenishment tank is connected at the lower part, ink is introduced from the replenishment tank into the ink storage chamber via the lower liquid communication pipe, while air is supplied from the ink storage chamber to the replenishment tank side via the upper gas communication pipe. A configuration adapted to be introduced is disclosed. However, even in this document, there is essentially no difference from Patent Documents 1 and 2 in the configuration in which the negative pressure generating member and the air communication port are arranged between the ink storage chamber and the recording head. The technique disclosed in the document cannot be applied without even the viewpoint of eliminating bubbles remaining in the ink supply path.
[0026]
[Patent Document 1]
JP-A-5-96744
[Patent Document 2]
JP-A-11-309876
[Patent Document 3]
US Pat. No. 6,347,863
[Patent Document 4]
JP-A-10-29318
[Problems to be solved by the invention]
As described above, Patent Documents 1 to 4 disclose the introduction of gas into the ink tank. However, the gas remaining in the ink supply path having a closed structure in use is smoothly transferred to the ink tank side. Neither of the purposes of transfer and retention to the United States was met.
[0031]
Therefore, the present invention provides a liquid supply system having a closed structure with respect to a liquid use part, which quickly and smoothly removes gas that hinders the liquid use operation and the liquid supply operation from the liquid supply path without complicating the structure. The purpose is to be able to eliminate.
[0032]
Another object of the present invention is to transfer the gas remaining in the ink supply path of the closed structure to the ink tank side smoothly and promptly, and to cause a problem caused by stagnant air bubbles even when the recording apparatus is actually used. That is, an object of the present invention is to provide an ink jet recording apparatus which does not cause recording failure due to defective ink supply or clogging of an ejection port due to a mixed bubble.
[0033]
It is another object of the present invention to utilize the above-described performance of transferring gas to the ink tank, thereby simplifying the configuration of the ink tank and reducing the cost.
[0034]
[Means for Solving the Problems]
Therefore, the liquid of the present invention has a liquid communication structure for liquid communication between a liquid storage unit for storing a liquid and a liquid using unit using the liquid, wherein the liquid communication structure is configured such that each of the liquid storage unit and the liquid storage unit A plurality of communication paths that communicate with the liquid use unit, wherein the liquid storage unit side is closed by the presence of the liquid in the liquid storage unit, and the liquid use unit side is the presence of the liquid in the liquid use unit. Forming a substantially closed space, and in a state where gas is present in the closed space, the gas can be transferred to the liquid storage unit through a part of the plurality of communication paths, and A valve mechanism is provided at a portion forming a space, and is provided with a valve mechanism capable of introducing outside air into the liquid supply path in accordance with the supply of the liquid to the liquid using section.
[0035]
Here, in a state where gas is present in the vicinity of at least a part of the plurality of communication passages on the side of the liquid use part, the liquid storage part is separated from the liquid storage part through a part of the plurality of communication paths. At the same time as the liquid moves, the gas is transferred to the liquid storage unit via another part of the plurality of communication paths.
[0036]
Then, in a state where gas is present in the vicinity of at least a part of the plurality of communication paths near the liquid use part, the liquid from the liquid storage part to the liquid use part through a part of the plurality of communication paths. As the liquid moves and the gas pressure in the liquid using section increases, the gas is transferred to the liquid storage section via a communication path of another part of the plurality of communication paths. Things.
[0037]
In the above, in the posture at the time of using the liquid, in the vertical direction, the liquid communication structure is positioned substantially lower than the liquid storage portion, and further positioned substantially higher than the liquid usage portion. can do.
[0038]
Further, the present invention resides in a liquid supply system that can supply the liquid from the liquid storage section to the liquid use section by using any one of the liquid communication structures described above.
[0039]
Here, the liquid storage section defines a liquid storage space, and at least a movable member that can be displaced in a direction that reduces the internal volume of the storage space with the supply of the liquid to the liquid use section. Further, the liquid storage portion may include an urging member for urging the movable member in a direction opposite to the direction of the displacement.
[0040]
Alternatively, the liquid storage section is provided in a state of liquid communication with the closed space to define a liquid storage space, and the liquid storage section supplies the liquid to the liquid use section through the liquid supply path. At least a part of the movable member can be displaced in a direction to reduce the volume of the space, and an urging member for urging the movable member in a direction opposite to the direction of the displacement can be provided.
[0041]
In the above, the valve mechanism may introduce the outside air when the negative pressure in the liquid supply path increases to a predetermined value or more.
[0042]
Further, the liquid storage section can be detachably attached to the liquid supply path via the plurality of communication paths.
[0043]
Here, a shutter member capable of closing the openings of the plurality of communication passages on the liquid storage unit side when the liquid storage unit is not mounted can be provided.
[0044]
In the above, the liquid using section is an ink jet recording head for performing recording by discharging ink as the liquid, and the ink can be guided to the ink jet recording head.
[0045]
Here, the recording head may be integrally configured to be separable.
[0046]
Further, the present invention uses such a liquid supply system, and in a posture during use, the plurality of communication paths are positioned substantially higher than the liquid supply path in the vertical direction, and further, the liquid storage unit Exists in an ink jet recording apparatus that performs recording while holding the liquid supply system so as to be positioned substantially higher than the plurality of communication paths.
[0047]
Furthermore, the present invention resides in a liquid tank which constitutes the liquid storage portion used in the liquid supply system of any of the above-described embodiments, and is connectable to the liquid supply path via the plurality of communication paths.
[0048]
Further, in the liquid supply system, the valve mechanism may permit introduction of the outside air into the liquid supply path, and may not permit movement of the liquid or gas in the opposite direction.
[0049]
Furthermore, the present invention relates to an ink jet recording head for performing recording by discharging ink as a liquid, characterized by integrally having any one of the above-described liquid communication structures.
[0050]
Here, the ink jet recording apparatus may have a form of a cartridge that is detachable from the ink jet recording apparatus.
[0051]
In addition, the liquid tank of the present invention has the form of a cartridge that forms the liquid storage portion connected to the liquid communication structure of any one of the above forms, and is connectable to the liquid communication structure via the plurality of communication passages. It is characterized by the following.
[0052]
Further, the liquid tank of the present invention has a form of a cartridge connectable to the liquid communication structure of the ink jet recording head through the plurality of communication paths.
[0053]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, some embodiments in which the present invention is applied to an inkjet recording apparatus will be described with reference to the drawings.
[0054]
In this specification, the term “record” refers to not only a case where significant information such as characters and figures are formed, but also a matter that is significant or insignificant, and is also manifested so that humans can perceive it visually. Regardless of whether or not the image, pattern, pattern, or the like is formed on a recording medium widely, or when the recording medium is processed.
[0055]
In addition, the “recording medium” includes not only paper used in general recording apparatuses but also a wide range of materials that can accept ink, such as cloth, plastic films, metal plates, glass, ceramics, wood, and leather. It should be noted that, hereinafter, it is also referred to as “paper” or simply “paper”.
[0056]
In the following embodiments, ink is described as an example of the liquid used in the liquid supply system of the present invention. However, the applicable liquid is not limited to ink, and is applicable to, for example, the inkjet recording field. Needless to say, it includes a processing liquid for the recording medium.
[0057]
(1st Embodiment)
FIG. 1 is a schematic sectional view of a liquid supply system according to a first embodiment of the present invention.
[0058]
The ink supply system of the embodiment shown in FIG. 1 generally includes an ink tank 10 as a liquid container, an ink jet recording head (hereinafter, simply referred to as a “recording head”) 20, and an ink supply path communicating between them. And a supply unit 50 to be formed. The supply unit 50 may be integral with the recording head 20 so as to be separable or non-separable. The supply unit 50 is provided on a carriage on which the recording head 20 is mounted. In the above, the ink supply path from the ink tank 10 to the recording head 20 may be closed.
[0059]
The ink tank 10 generally includes an ink storage chamber 12 in which an ink storage space is defined. In the ink storage chamber 12, ink to be discharged from the recording head is stored, and supplied to the recording head along with the discharging operation. You.
[0060]
In the ink storage chamber 12, a deformable flexible film (sheet member) 11 is provided in a part, and a space for storing ink is defined between this part and the inflexible exterior 15. ing. An outer space with respect to the ink storage space as viewed from the sheet member 11, that is, a space above the sheet member 11 in the drawing is opened to the atmosphere and made equal to the atmospheric pressure. Further, the inside of the ink storage space forms a substantially closed space except for a connection portion to a supply member provided below and a communication passage 13 to a valve chamber.
[0061]
The shape of the central portion of the sheet member 11 of this example is regulated by a pressure plate 14 which is a flat support member, and the peripheral portion thereof is deformable. The central portion of the sheet member 11 is formed in a convex shape in advance, and the side surface shape is substantially trapezoidal. As will be described later, the sheet member 11 is deformed according to a change in the amount of ink in the ink storage space or a change in pressure. At that time, the peripheral portion of the sheet member 11 expands and contracts in a well-balanced manner, and the central portion of the sheet member 11 moves in parallel in the left-right direction in FIG. As described above, since the sheet member 11 is smoothly deformed (moved), no shock is generated due to the deformation, and no abnormal pressure fluctuation occurs in the ink storage space due to the shock.
[0062]
In the ink storage space, a pressing force for urging the sheet member 11 rightward in the drawing is applied via the pressure plate 14 so as to balance the holding force of the meniscus formed in the ink ejection portion of the recording head. A spring member 40 in the form of a compression spring for generating a negative pressure within a range in which the ink ejection operation of the recording head is possible is provided. At the same time, when the volume of the air in the ink storage chamber fluctuates due to environmental changes (ambient temperature and atmospheric pressure), it is received by the displacement of the spring and the sheet, so that the negative pressure in the chamber does not fluctuate greatly. (This expression should be reflected in other matters. This mechanism is mainly a buffer effect and generates a certain degree of negative pressure. The one-way valve is the main control of the negative pressure in the tank ) 19 is a fixing member for supporting the spring member 40.
[0063]
The state shown in FIG. 1 shows a state in which the ink storage space is almost completely filled with ink. However, in this state, the spring member 40 is in a compressed state, and an appropriate negative pressure is stored in the ink storage space. It is assumed that pressure is generated.
[0064]
The connection between the recording head 20 and the ink tank 10 is made by inserting the connecting portion 51 of the supply section 50 provided integrally with the recording head in the illustrated example into the ink tank 10. As a result, the two are fluidly connected, and ink can be supplied to the recording head 20. A sealing member 17 made of rubber or the like is attached to the opening on the ink tank side through which the connection portion 51 is inserted. The sealing member 17 is in close contact with the periphery of the connection portion 51 to prevent ink from leaking from the ink tank 10, and The connection between the ink tank 51 and the ink tank 10 is secured. Note that a slit or the like may be formed in the sealing member 17 in advance at the insertion position in order to facilitate the insertion of the connection portion 51. When the connection portion 51 is not inserted, the slit is closed by the elastic force of the sealing member 17 itself, thereby preventing leakage of ink.
[0065]
The connection portion 51 is a hollow needle-like member whose inside is divided into two parts along the axial direction, and an opening position (hereinafter, referred to as a tank-side opening position) of each of the hollow portions that is positioned on the upper side, that is, in the ink storage chamber 12. Have substantially the same height in the vertical direction, but have a different height at the opening position on the lower side, that is, in the supply unit connected to the head (hereinafter referred to as the head-side opening position). Hereinafter, the flow path (the right flow path in the drawing) in which the head side opening position in the supply unit 50 is relatively lower in the vertical direction is the ink flow path 54, and the head side opening position is the upper side in the vertical direction. Is referred to as an air flow path 54. In the air bubble elimination process, ink is mainly led out from the ink flow path 53 to the recording head side, and the air flow path 54 This is because air is transferred to the ink tank side, and both ink and air are moved in each flow path as described later. That is, the names of these flow paths do not mean that they are dedicated to each fluid.
[0066]
The ink supply path in the supply unit 50 has a cross section that gradually expands from the connection (upstream) side with the ink tank 10 and decreases toward the recording head 20 (downstream). A filter 23 is provided at the maximum enlargement portion of the ink supply path to prevent impurities mixed in the supplied ink from flowing into the recording head 20. The gas-liquid interface in the supply section 50 formed by the stagnation of the gas is larger than the cross-sectional area of the flow paths 53 and 54. By doing so, when the head difference of the ink in the ink tank 10 is applied to the ink in the supply unit 50 through the flow path 53, the pressure of the gas existing in the supply unit 50 is further increased, and The gas can be easily discharged toward the ink tank 10.
[0067]
The supply unit 50 is provided with a one-way valve for introducing a gas (air) from the outside when the negative pressure in the ink supply path becomes higher than a predetermined value and for preventing ink leakage from the supply unit 50. Can be The one-way valve is provided with a pressure plate 34 having a communication port 36 and serving as a valve closing member, and a sealing member 37 fixed at a position facing the communication port 36 on the inner wall of the valve chamber housing and capable of sealing the communication port 36. And a sheet member 31 joined to the pressure plate and having the communication port 36 penetrated therethrough. Even in the valve chamber 30, the communication port 13 to the supply unit 50 and the communication port 36 to the atmosphere are substantially excluded. Maintains a closed space. The space in the valve chamber housing on the left side of the figure from the seat member 31 is opened to the atmosphere through the atmosphere communication port 32, and is made equal to the atmospheric pressure.
[0068]
The peripheral portion of the sheet member 31 other than the central portion that is joined to the pressure plate 34 is deformable. With such a configuration, the movement of the pressure plate 34 as the valve closing member in the left-right direction in the figure is smoothly performed.
[0069]
Inside the valve chamber 30, a spring member 35 is provided as a valve regulating member for regulating the opening operation of the valve. Also in this case, the spring member 35 is kept in a slightly compressed state, and the pressure plate 34 is pushed leftward in the drawing by the reaction force of the compression. Due to the expansion and contraction of the spring member 35, the sealing member 37 is brought into close contact with and separated from the communication port 36, thereby providing a function as a valve. Further, gas from the atmosphere communication port 32 to the inside of the valve chamber 30 through the communication port 36 is provided. It has a one-way valve mechanism that allows only introduction.
[0070]
Here, as the seal member 37, any material may be used as long as the communication port 36 is securely sealed. That is, at least a portion that is in contact with the communication port 36 has a shape that maintains flatness with respect to the opening surface, or has a rib that can be in close contact with the periphery of the communication port 36, and further has a tip inside the communication port 36. Any shape may be used as long as it can secure the close contact state, such as a shape having a shape that allows the communication port 36 to enter and close the communication port 36, and the material is not particularly limited. However, since this close contact is achieved by the extension force of the spring member 35, it is easy to follow the sheet member 31 and the pressure plate 34 which move by the action of the extension force, that is, elasticity such as rubber having contractility. It is more preferred to form the sealing member with the body.
[0071]
The recording head 20 has a predetermined direction (for example, a direction different from the moving direction in the case of a serial recording method in which the recording head 20 is mounted on a member such as a carriage and performs a discharging operation while relatively moving with respect to the recording medium). 2), a plurality of discharge ports, a liquid path communicating with each discharge port, and an element which is disposed in the liquid path and generates energy used for discharging ink. Here, the method of ejecting ink in the recording head, that is, the form of the energy generating element is not particularly limited. For example, an electrothermal converter that generates heat in accordance with energization is used as the element, and the generated thermal energy is used for ink ejection. It may be used for. In this case, the heat generated by the electrothermal transducer causes film boiling in the ink, and the foaming energy at that time allows the ink to be ejected from the ink ejection port. Alternatively, an electromechanical conversion element such as a piezo element that deforms in response to application of a voltage may be used, and ink may be ejected using the mechanical energy.
[0072]
The recording head 20 and the supply unit 50 may be integrated so as to be separable or inseparable, or may be configured separately and connected via a communication path. When integrated, a cartridge that can be attached to and detached from a mounting member (for example, a carriage) in the recording apparatus can be used.
[0073]
In the illustrated example, the spring 40 in the ink storage chamber 12 and the spring 35 in the valve chamber 30 are both schematically shown as coil springs. However, it is a matter of course that other forms of springs can be used. . In particular, for example, a conical spring may be used, or a leaf spring may be used. Further, when a leaf spring is used, a pair of leaf spring members having a substantially U-shaped cross section may be combined with the U-shaped open ends corresponding to each other.
[0074]
The process of removing air bubbles from the ink tank staying in the supply unit 50 will be described with reference to FIGS.
[0075]
FIG. 2 shows a state in which a new ink tank 10 is not mounted on the supply unit 50 or the recording head 20. Here, the ink tank 10 is completely filled with the ink I, a negative pressure is generated by the spring member 40, and the sheet member 11 projects outside the ink tank. On the recording head 20 side, even if the ink tank 10 mounted so far becomes empty, recording is performed using the ink remaining in the supply unit 50, so air enters from the ink tank side, The gas is stored at the upper part in the upstream region of the filter 23 in the supply part 50.
[0076]
FIG. 3 shows a state at the moment when a new ink tank 10 is mounted from the state of FIG. Since the recording head 20 or the supply unit 50 side is open to the atmosphere, the gas pressure in the upstream region of the filter 23 is equal to the atmospheric pressure. On the other hand, the pressure inside the ink tank is lower than the atmospheric pressure (negative pressure) by the spring member 40. As a result, at the moment the ink tank 10 is mounted, a part of the gas in the upstream area of the filter 23 moves into the ink storage chamber 12 and accumulates in the upper part thereof, and the pressure between the ink storage chamber 12 and the supply unit 50 increases. Averaged. However, the ink forms a meniscus in each of the ink flow path 53 and the air flow path 54 of the connecting portion 51, and the movement of the gas is stopped when the pressure balance is balanced by the meniscus. Depending on the volume of gas on the supply unit side, gas removal may be completed in this state, but in the case shown, the volume of gas is large and the gas to be removed remains.
[0077]
FIG. 4 schematically shows a state where ink is ejected from the recording head 20 as, for example, droplets. When the ink is ejected, the negative pressure in the recording head 20 or the supply unit 50 increases, breaking the meniscus of the ink formed in the connection unit 51, and moving the ink from the ink tank 10 toward the supply unit 50. Accordingly, the inner volume of the ink storage chamber 12 decreases, and the sheet member 11 is deformed downward while being regulated by the pressure plate 14. Thereby, the spring member 40 is compressed, and the negative pressure in the ink storage chamber 12 is also increased.
[0078]
Here, in the present embodiment, the diameters of the ink flow path 53 and the air flow path 54 are substantially equal to each other, so that the pressure loss in the flow path is large with respect to the negative pressure in the recording head 20 or the supply unit 50. There is no difference, and ink is supplied from each of the flow paths. In the illustrated state where the head side opening 53h of the ink flow path 53 is in contact with the ink, the ink flows from the ink flow path 53 as it is, while bubbles generated in the supply unit 50 or the recording head 20 move to the filter upstream area. , And stay in the region, that is, the upper portion of the supply unit 50 together with the gas that has already remained. In this state, the ink forms a meniscus at the position of the head side opening 54h of the air flow path 54, but drops if the negative pressure in the recording head 20 or the supply unit 50 is high. In the present embodiment, the connection portion 51 is filled with ink by ink ejection accompanying the printing operation or ink ejection (preliminary ejection) performed as an operation other than the printing operation. This state can be obtained by sealing the outlet forming surface with a cap member and discharging the ink from the discharge port by a suction pump.
[0079]
FIG. 5 shows a state in which ink ejection or ink suction from the ejection port forming surface side has stopped. In this state, due to the head difference, a force is generated in the ink flow path 53 to cause the ink to move to the supply unit 50, and a force is generated in the air flow path 54 to cause the air to be discharged to the ink tank 10 side. .
[0080]
FIG. 6 shows a state in which the movement of the ink to the supply unit 50 and the discharge of the air to the ink tank 10 side are simultaneously proceeding by these forces.
[0081]
FIG. 7 shows a state in which the gas-liquid interface in the upstream region of the filter has risen to the position of the head-side opening 54h of the air flow path 54. Then, in this state, the movement of the ink and the discharge of the air are stopped.
[0082]
As described above, according to the present embodiment, the inside of the connection part 51 is divided into two to provide two flow paths, and the height of the head-side opening position of each flow path is made different, so that a complicated configuration is achieved. The gas remaining in the upstream region of the filter can be quickly transferred to the ink tank side without the need.
[0083]
Also, if a small amount of ink is ejected or the ink is sucked from the ejection port forming side after the ink tank replacement operation, the gas remaining in the supply section is quickly and smoothly transferred to the ink tank side and removed from the supply path. As a result, a large amount of ink is not wasted as in the case of removing gas by performing a suction operation from the ejection port side.
[0084]
Next, referring to FIGS. 1, 8, and 9, when the pressure in the ink supply system becomes smaller than a predetermined value in the process of supplying the ink from the ink tank 10 to the recording head 20 (the negative pressure becomes the predetermined value). The operation of the above (when it is increased above) will be described.
[0085]
Ink consumption (supply of ink to the recording head) starts from the initial state in FIG. 1 in which the ink tank 10 is sufficiently filled with ink, and the sheet member 11 or the pressure plate 14 follows the ink consumption (content of the ink storage space). The displacement proceeds in the direction of decreasing the product (to the left in FIG. 1) to reach the position shown in FIG.
[0086]
As the ink consumption further progresses from this state, the pressure in the ink supply system from the ink tank 10 to the recording head 20 decreases (the negative pressure increases) by the reduced amount of ink inside.
[0087]
Then, as shown in FIG. 9, the ink consumption is further continued from the state where the negative pressure in the ink supply system and the force acting by the valve regulating member in the valve chamber 30 are balanced, and the negative pressure further increases. At the moment, the communication port 36 is opened, the air flows in, and the ink is taken into the supply unit 50. At this time, the negative pressure in the supply unit 50 is reduced, and the communication port 36 is closed. As described above, a predetermined negative pressure is stably applied to the ink flow path and the head by the valve unit, thereby improving the ejection characteristics of the head. On the other hand, due to the balance with the negative pressure in the ink tank 10, the gas in the supply unit 50 is supplied to at least one of the flow paths formed in the connection unit 51 (if only the head side opening 54 h is in contact with the gas). The ink is transferred into the ink tank 10 via the air passage 54).
[0088]
As described above, by appropriately introducing gas into the ink tank 10, almost all of the stored ink can be efficiently consumed.
[0089]
In addition, the valve chamber 30 is arranged on the supply unit 50 side to enable intake of outside air, and the gas can be smoothly transferred from the supply unit 50 side to the ink tank side. This is advantageous in terms of simplifying the configuration of a certain ink tank 10 and reducing the cost.
[0090]
Further, in the configuration of the ink tank 10, even if a change in the surrounding environment of the ink tank, for example, a rise in temperature or a decrease in pressure, occurs, the position of the sheet member 11 or the pressure plate 14 from the maximum displacement position to the left to the initial position. Since the expansion of the air taken into the storage space is permitted by the intervening volume, in other words, the space corresponding to the volume functions as a buffer area, so that the pressure increase due to the change in the surrounding environment is reduced. In addition, it is possible to effectively prevent ink from leaking from the ejection port.
[0091]
In addition, since the internal volume of the ink storage space is reduced due to the derivation of the liquid from the initial filling state and gas is not transferred until the buffer area is secured, sudden changes in the surrounding environment, vibration and No ink leakage occurs even if a drop occurs. Further, since the buffer area is not reserved in advance from the state where the ink is not used, the volume efficiency of the ink container is high, and a compact configuration can be achieved.
[0092]
In addition, when a pigment containing pigment is used as the ink, when the air is transported to the tank, the sedimentation of the pigment particles is diffused, and the storage stability of the ink and the reliability of the ejection can be secured.
[0093]
(Second embodiment)
According to the first embodiment described above, the gas remaining in the supply unit 50 or the gas introduced into the supply unit 50 from the valve chamber 30 is supplied to the connection unit 51 by balancing the pressures in the ink tank 10 and the supply unit 50. As a result, the ink stored in the ink tank 10 can be efficiently and almost completely consumed.
[0094]
FIG. 10A shows a state in which the ink tank has been removed for replacement after all the ink stored in the ink storage section has been used up, and FIG. This shows a state where a new filled ink tank is mounted.
[0095]
As is clear from FIGS. 10A and 10B and as described with reference to FIG. 2, when the ink tank 10 is removed, the tank-side openings 53t and 54h of the connection portion 51 are open to the atmosphere. Therefore, since the recording head 20 or the supply unit 50 side is open to the atmosphere, the pressure of the gas in the upstream region of the filter 23 is equal to the atmospheric pressure. On the other hand, the pressure inside the ink tank is lower than the atmospheric pressure (negative pressure) by the spring member 40. As a result, at the moment the ink tank 10 is mounted, a part of the gas in the upstream area of the filter 23 moves into the ink storage chamber 12 and accumulates in the upper part thereof, and the pressure between the ink storage chamber 12 and the supply unit 50 increases. Averaged. However, the ink forms a meniscus in each of the ink flow path 53 and the air flow path 54 of the connecting portion 51, and the movement of the gas is stopped when the pressure balance is balanced by the meniscus. Depending on the volume of gas on the supply unit side, gas removal may be completed in this state, but in the case shown, the volume of gas is large and the gas to be removed remains.
[0096]
Therefore, by discharging or forcibly discharging the ink from the recording head 20, the negative pressure in the recording head 20 or the supply unit 50 is increased, and the meniscus of the ink formed in the connection unit 51 is broken, and the ink supply from the ink tank 10 to the supply unit 50 is stopped. , And the gas on the supply unit 50 side is transferred to the ink tank 10.
[0097]
In the case of this configuration, there is no problem if the ink tank replacement does not require time, but if the ink tank is removed and left for a long time, the communication path is open to the atmosphere, so a positive pressure is applied to the nozzle, When an external factor such as vibration is applied, the ink may leak from the nozzle. In addition, the ink may evaporate from the communication passage, and the ink may adhere to that portion.
[0098]
FIG. 11 is a schematic cross-sectional view of a liquid supply system according to the second embodiment, which further achieves long-term reliability in the above configuration. In this configuration, a shutter 57 made of an elastic member such as rubber capable of closing the tank-side opening 53t of the ink flow path 53 and the tank-side opening 54t of the air flow path 54 provided in the connection portion 51, and the shutter 57 The supply unit 50 is provided with a spring 58 for supporting it in a position.
[0099]
With this configuration, when the ink tank 10 is removed, the spring 58 that has been compressed by the ink tank 10 expands, the shutter 58 closes the tank-side opening 53t and the tank-side opening 54t, and the supply unit 50 The internal pressure is maintained. In a state in which a new ink tank 10 is mounted, the spring 59 is compressed in accordance with the mounting operation, and the openings 53t and 54t are opened in the ink tank with the connecting portion 51 protruding into the ink tank 10. .
[0100]
That is, since the head-side closed state is maintained throughout the ink tank replacement operation, even if the ink tank is removed for a long time, ink sticking does not occur and the negative pressure on the head is also maintained. Therefore, problems such as ink dripping from the nozzles do not occur.
[0101]
(Third embodiment)
Next, the configuration of a liquid supply system for further simplifying and reducing the configuration of the ink tank will be described.
[0102]
FIG. 12 is a schematic sectional view of a liquid supply system for explaining such a configuration. This embodiment is different from the first embodiment in that the ink tank 10 ′ is configured to store the ink as it is without providing the means for realizing the negative pressure yesterday and the buffer function described above, A function room 400 for realizing a function is provided on the supply unit 50 side.
[0103]
Here, the inside of the housing constituting the functional room 400 is partitioned into two spaces by a deformable flexible film (sheet member) 411, and one of the partitioned spaces is connected to the atmosphere through the communication port 432. It is open to and equal to atmospheric pressure. The other space is connected to the supply unit 50 via the communication port 413, and communicates with the ink.
[0104]
The shape of the central portion of the sheet member 411 is regulated by a pressure plate 414, which is a flat support member, and the peripheral portion thereof is deformable. The central portion of the sheet member 411 is formed in advance in a convex shape toward the space open to the atmosphere, and the side surface shape is substantially trapezoidal. Further, by applying a pressing force for urging the sheet member 411 upward in the drawing via the pressure plate 414 in the ink communication side space, the holding force of the meniscus formed in the ink ejection portion of the recording head is exerted. A spring member 440 in the form of a compression spring for generating a negative pressure in a range in which the ink discharge operation of the recording head is possible in equilibrium with the above is provided.
[0105]
That is, the inside of the function chamber 400 is configured substantially the same as the inside of the ink tank 10 in the first embodiment, and performs the same function. The state of FIG. 12 shows a state in which the ink is almost completely filled in the ink tank 10 ′. In this state, the spring member 440 is in a compressed state, and the ink supply system has an appropriate state. It is assumed that a negative pressure is generated.
[0106]
The operation of the present embodiment will be described with reference to FIGS.
FIG. 13 shows a state in which the ink is started to be discharged from the initial state of FIG. 12. First, the sheet member 411 or the pressure plate 414 is deformed, the inner volume of the ink communication side space of the functional chamber 400 is contracted, and the buffer area is reduced. Secured.
[0107]
FIG. 14 shows that after this, the ink is further discharged and the negative pressure in the liquid supply system including the ink communication side space of the functional chamber 400 increases, so that outside air is taken into the supply section 50 from the valve chamber 30 and the ink tank 10 The state has begun to transfer gas to '.
[0108]
FIG. 15 shows a state in which the gas retained in the supply unit 50 or the gas introduced into the supply unit 50 from the valve chamber 30 is appropriately transferred to the ink tank 10 ′, and the ink is moved into the supply chamber 50. FIG. 10 is an explanatory diagram of a state where ink stored in 10 ′ is efficiently consumed. When an environmental change such as a rise in temperature or a decrease in pressure occurs in such a state, the gas in the ink tank 10 'or the supply unit 50 expands, and the pressure in the ink supply system increases. Since this is absorbed by the buffer function performed by the function chamber 400, it is possible to prevent an undesired pressing force from acting on the recording head 20.
[0109]
In this embodiment, the functional parts are hardly provided in the ink tank, which is a consumable, and the consumable is provided on the head side, so that the cost of the consumable can be extremely reduced. In addition, a one-way valve that permits the introduction of air to the head and does not permit the discharge of ink and air in the supply path, and a buffer that maintains a predetermined negative pressure in response to environmental changes are provided. As a result, the buffer plays a role of a capacitor that smoothes the ripple instantaneously with respect to the negative pressure fluctuation (ripple) generated when air is introduced from the valve, so that the negative pressure fluctuation with respect to the head is further suppressed. This makes the ejection characteristics of the head extremely stable.
[0110]
(Structural example of inkjet recording device)
FIG. 16 is a diagram for describing a configuration example of an inkjet recording apparatus to which the present invention can be applied.
[0111]
The recording device 150 of this example is a serial scan type ink jet recording device, and a carriage 153 is guided by guide shafts 151 and 152 movably in the main scanning direction indicated by the arrow A. The carriage 153 is reciprocated in the main scanning direction by a driving force transmission mechanism such as a carriage motor and a belt for transmitting the driving force. In the carriage 153, a liquid supply system 154 including any of the above-described embodiments and a recording head or a supply unit and an ink tank mounted on the carriage and supplying ink is mounted. After the paper P as a recording medium is inserted from an insertion slot 155 provided at the front end of the apparatus, its transport direction is reversed, and then transported by a feed roller 156 in the sub-scanning direction of arrow B. The recording device 150 performs a recording operation of ejecting ink toward a recording area of the sheet P on the platen 157 while moving the recording head in the main scanning direction, and moving the sheet P in the sub-scanning direction by a distance corresponding to the recording width. The image is sequentially recorded on the sheet P by repeating the transport operation of transporting the image to the paper P.
[0112]
Note that, as described above, the recording head may use the thermal energy generated from the electrothermal converter as the energy for ejecting the ink. In such a case, the heat generated by the electrothermal transducer causes film boiling in the ink, and the ink can be ejected from the ink ejection port by the foaming energy at that time. Further, the method of ejecting ink in the recording head is not limited to the method using such an electrothermal transducer, and may be, for example, a method of ejecting ink using a piezoelectric element.
[0113]
A recovery system unit (recovery processing unit) 158 is provided at the left end of the moving area of the carriage 153 in FIG. The recovery system unit 158 is provided with a cap capable of capping the ink discharge port of the recording head, a suction pump capable of introducing a negative pressure into the cap, and the like. By applying the pressure, the ink can be sucked and discharged from the ink discharge port, and a recovery process for maintaining a good ink discharge state of the recording head can be performed. In addition to the image formation, a recovery process (also referred to as a preliminary discharge process) for maintaining a good ink discharge state of the recording head by discharging ink from the ink discharge ports toward the inside of the cap can be performed.
[0114]
(Other)
Note that the configuration of the connection part for smooth gas-liquid exchange between the ink tank and the supply part, particularly the configuration of the ink flow path for smoothly starting the ink movement accompanying the gas transfer, is as described above. However, the present invention is not limited to the configuration in which the head side opening is located at a relatively low position in the vertical direction.
[0115]
Even if the height difference is not provided between the position of the head side opening of the ink flow path and the position of the head side opening of the air flow path, for example, as described above, And one part of the opening on the head side is in contact with the inner wall surface of the supply unit, or a part that forms a fine groove along one flow path is additionally provided. To protrude inward from the supply section, so that a meniscus that applies high pressure is not formed at the head-side opening, whereby ink flows down from the flow path into the supply section. Can be made easier.
[0116]
In addition, the shape of the opening portion is enlarged, the diameter of the flow path is made different, or the state of the inner surface of the flow path is different between the flow paths by appropriately selecting a material or performing a surface treatment. The same effect can be expected by doing so.
[0117]
In addition, instead of providing a connection part having an ink flow path and an air flow path on the recording head side or the ink supply part side, the connection part may be provided on the ink tank side so as to be able to enter the supply part.
[0118]
In addition, instead of dividing the inside into two parts and forming two flow paths, the connection part may be a separate member that forms each flow path. Furthermore, the number of channels is not limited to two, and three or more channels may be provided. Also, in the case where the inside is divided into a plurality of portions to form a connection portion that forms a plurality of flow channels, not only the partition between the flow channels is formed linearly but also concentrically as in the above example. Can be used as a connecting portion having a multi-pipe configuration.
[0119]
Further, in the case where the inside is divided into a plurality of sections to form a plurality of flow paths, each flow path is not limited as long as the transfer of gas and the movement of ink do not interfere with each other and hinder smooth and rapid gas-liquid exchange. The road does not have to be completely partitioned.
[0120]
In the above-described embodiments of the ink supply system, basically, any structure is adopted in which the ink is stored or supplied as it is without holding the ink in the absorber or the like, while the movable member (sheet member, pressure plate) And a spring member for urging the negative pressure, the negative pressure generating means is constituted, and the supply system has a closed structure so that an appropriate negative pressure is applied to the recording head.
[0121]
Such a configuration has a higher volumetric efficiency and a higher degree of freedom in ink selection as compared with the conventional configuration in which a negative pressure is generated by the absorber. In addition, the present invention can preferably respond to demands for a higher flow rate and stabilization of ink supply, which are required with the recent increase in printing speed. However, it goes without saying that the present invention can be applied to a configuration in which the absorber is provided in a part of the ink tank.
[0122]
Further, for the purpose of eliminating gas remaining in the supply path, the ink is transferred to the ink tank at the most upstream position farthest from the recording head, and for this purpose, the ink tank is connected to the ink tank through a plurality of flow paths. The ink supply path is connected, and the derivation of ink from the ink tank and the introduction of gas into the ink tank are performed in parallel by utilizing the balance between the two pressures.
[0123]
According to this configuration, the gas remaining in the supply path can be smoothly and promptly removed from the ink tank side without using a complicated device and having a simple structure with a small increase in the number of parts. In addition, the timing of the elimination is naturally performed in accordance with the balance of the pressure when the gas is accumulated to some extent, so that the reliability of the elimination of the gas is high. In addition, such a configuration is advantageous in that, even when a valve mechanism for maintaining a negative pressure by introducing outside air into the ink supply path, that is, the supply unit, is provided, if the amount of introduced gas increases, it is automatically eliminated. This is a configuration that can further contribute to the simplification and cost reduction of the configuration as compared with the case where a negative pressure is generated by the ink tank.
[0124]
Further, since the negative pressure of the ink tank is constantly maintained in the process of removing gas, it is possible to reliably prevent liquid leakage from the ink discharge port of the ink jet recording head. Furthermore, by eliminating gas to the ink tank side, ink consumption can be significantly reduced compared to a method in which gas is eliminated by suctioning ink from the ejection port side of the recording head. This contributes to reducing running costs.
[0125]
In addition, in the case of using an ink tank configured to be detachable with respect to the supply path, conventionally, the supply path is filled with ink to prevent gas from entering the supply path during the replacement operation. In many cases, the ink tank is replaced in a state where the ink is completely consumed, that is, before the ink is completely consumed. However, according to the above configuration, even if gas enters the supply path during the replacement operation, it can be easily removed from the ink tank by installing a new ink tank. This can not only further reduce running costs, but also greatly contribute to environmental problems.
[0126]
Further, in each of the above-described embodiments, the ink tank is disposed at the highest position in a normal use posture, and the supply unit or the recording head is disposed at a low position. This is a very preferable arrangement for performing gas-liquid exchange quickly, smoothly, and with a simple configuration.
[0127]
Depending on the configuration of the ink tank, the gas introduced into the ink tank may be stored anywhere in the ink tank as long as the gas does not return to the ink supply path and the ink supply is not hindered. However, the configuration of the above embodiment in which the ink is stored without being impregnated into the absorber or the like is preferable because the introduced gas is located at the uppermost portion in the ink tank as it is.
[0128]
When the absorber is not present in the ink tank, the volume of the tank itself can be the capacity of the ink. Therefore, it is not necessary to enlarge the ink tank more than necessary, and the shape of the tank is relatively free. It is possible to design.
[0129]
In the above description, a serial type ink jet recording apparatus has been applied as the recording method of the present embodiment, but the present invention and the present embodiment are not limited to this. Also, the present invention and the present embodiment can be applied to a line scanning type recording apparatus instead of a serial type. Further, it goes without saying that a plurality of liquid supply systems can be provided corresponding to the color tone (color, density, etc.) of the ink.
[0130]
【The invention's effect】
As described above, according to the present invention, in a liquid supply system having a closed structure with respect to a liquid use part, a gas that hinders a liquid use operation and a liquid supply operation can be dispensed with a liquid without complicating the structure. It can be quickly and smoothly removed from the supply route.
[0131]
Also, when applied to an ink jet recording apparatus, the gas remaining in the ink supply path of the closed structure can be smoothly and promptly transferred to the ink tank side, and even when the recording apparatus is actually used, there is a problem caused by stagnant bubbles. That is, it is possible to prevent a recording failure due to a defective ink supply or clogging of an ejection port due to a mixed bubble.
[0132]
In addition, when a pigment containing pigment is used as the ink, when the air is transported to the tank, the sedimentation of the pigment particles is diffused, and the storage stability of the ink and the reliability of the ejection can be secured.
[0133]
Further, in the present invention, a mechanism for introducing outside air to maintain a negative pressure in the ink supply system in a preferable state is provided on the ink supply path side by utilizing the above-described performance of removing gas to the ink tank. Accordingly, the configuration of the ink tank can be simplified and the cost can be reduced.
[0134]
As described above, according to the present invention in which ink can be supplied in a state where the negative pressure to the head is stabilized, printing performance, reliability, and cost reduction can be simultaneously realized.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a liquid supply system according to a first embodiment of the present invention.
FIG. 2 is a diagram for explaining a gas removing process in the first embodiment, and is a schematic cross-sectional view showing a state where a new ink tank is not mounted on a supply unit or a recording head.
FIG. 3 is a diagram for explaining a gas removal process in the first embodiment, and is a schematic cross-sectional view showing a state at the moment when a new ink tank is mounted from the state of FIG. 2;
FIG. 4 is a diagram for explaining a gas removing process in the first embodiment, and is a schematic cross-sectional view showing a state in which ink is ejected from a recording head.
FIG. 5 is a diagram for explaining a gas removing process in the first embodiment, and is a schematic cross-sectional view showing a state in which ink discharge or discharge in FIG. 4 is stopped.
FIG. 6 is a diagram for explaining a gas removing process in the first embodiment, and is a schematic cross-sectional view showing a state in which ink movement and gas discharge are proceeding simultaneously from the state of FIG. 6;
FIG. 7 is a diagram for explaining a gas removal process in the first embodiment, and is a schematic cross-sectional view showing a state where ink movement and gas discharge are stopped.
FIG. 8 is an explanatory diagram for explaining an outside air intake operation for negative pressure adjustment in the first embodiment.
FIG. 9 is an explanatory diagram for explaining an outside air intake operation for negative pressure adjustment in the first embodiment.
FIGS. 10A and 10B are explanatory diagrams for explaining a state at the time of an ink tank replacement operation according to the configuration of the first embodiment.
FIG. 11 is a schematic sectional view illustrating a configuration of a liquid supply system according to a second embodiment of the present invention.
FIG. 12 is a schematic sectional view illustrating a configuration of an ink supply system applied to a third embodiment of the present invention.
FIG. 13 is a schematic sectional view for explaining the operation of the liquid supply system according to the third embodiment.
FIG. 14 is a schematic sectional view for explaining the operation of the liquid supply system according to the third embodiment.
FIG. 15 is a schematic sectional view for explaining the operation of the liquid supply system according to the third embodiment.
FIG. 16 is a perspective view illustrating a configuration example of an inkjet recording apparatus to which the present invention can be applied.
[Explanation of symbols]
REFERENCE SIGNS LIST 10 ink tank 11 sheet member 12 ink storage chamber 13 communication port 14 pressure plate 17 sealing portion 19 fixing member 20 recording head 22 filter 30 valve chamber 31 valve chamber seat member 34 valve chamber pressure plate 35 valve chamber spring members 32, 36 communicate Port 37 Seal member 40 Spring member 50 Supply unit 51 Connection unit 53 Ink flow path 54 Air flow path 150 Ink jet recording device 154 Liquid supply system 153 Carriage 158 Recovery system unit 430 Function room 431 Valve room seat member 434 Valve room pressure plate 435 Valve Chamber spring members 432, 436 Communication port

Claims (19)

A liquid communication structure for liquid communication between a liquid storage unit for storing a liquid and a liquid using unit using the liquid,
The liquid communication structure includes a plurality of communication paths each communicating the liquid storage unit and the liquid use unit,
The liquid storage unit side is closed by the presence of the liquid in the liquid storage unit, and the liquid use unit side forms a substantially closed space by the presence of the liquid in the liquid use unit,
In a state where a gas exists in the closed space, the gas can be transferred to the liquid storage unit through a part of the plurality of communication paths,
A liquid communication structure, comprising: a valve mechanism provided at a portion forming the closed space and capable of introducing outside air into a liquid supply path as the liquid is supplied to the liquid using section. In a state where gas is present in the vicinity of at least a part of the plurality of communication paths near the liquid use part, the liquid is transferred from the liquid storage unit to the liquid use part via a part of the plurality of communication paths. The liquid communication structure according to claim 1, wherein the gas is transferred to the liquid storage unit via another part of the plurality of communication paths at the same time as the movement of the plurality of communication paths. In a state where gas is present in the vicinity of at least a part of the plurality of communication paths near the liquid use part, the liquid is transferred from the liquid storage unit to the liquid use part via a part of the plurality of communication paths. Is moved to increase the gas pressure in the liquid using part, so that the gas is transferred to the liquid storage part through the communication path of another part of the plurality of communication paths. The liquid communication structure according to claim 2, wherein: The liquid communication structure according to claim 1, wherein the liquid communication structure is positioned substantially lower than the liquid storage portion and further substantially higher than the liquid usage portion in a vertical direction in a posture when the liquid is used. 4. The liquid communication structure according to any one of 1 to 3. A liquid supply system capable of supplying the liquid from the liquid storage section to the liquid use section using the liquid communication structure according to any one of claims 1 to 4. The liquid storage unit defines a liquid storage space, and at least a part of a movable member that can be displaced in a direction in which the internal volume of the storage space decreases with the supply of the liquid to the liquid use unit. The liquid supply system according to claim 5, comprising: The liquid supply system according to claim 6, wherein the liquid storage unit includes an urging member that urges the movable member in a direction opposite to the direction of the displacement. A liquid storage space is provided in the closed space to define a liquid storage space, and with the supply of the liquid from the liquid storage unit to the liquid use unit via the liquid supply path, the storage space 6. The apparatus according to claim 5, further comprising a biasing member that biases the movable member in a direction opposite to the direction of the displacement, at least partially including a movable member that can be displaced in a direction to reduce the volume. A liquid supply system as described. 9. The liquid supply system according to claim 5, wherein the valve mechanism introduces the outside air when a negative pressure in the liquid supply path increases to a predetermined value or more. The liquid supply system according to claim 9, wherein the valve mechanism permits the introduction of the outside air into the liquid supply path, and prevents movement of the liquid or gas in the opposite direction. The liquid supply system according to any one of claims 5 to 10, wherein the liquid storage unit is detachably attached to the liquid supply path via the plurality of communication paths. The liquid supply system according to claim 11, further comprising a shutter member capable of closing the openings of the plurality of communication paths on the liquid storage unit side when the liquid storage unit is not mounted. 13. The ink jet recording head for performing recording by ejecting ink as the liquid, wherein the liquid using section guides the ink to the ink jet recording head. Liquid supply system. 14. The liquid supply system according to claim 13, wherein the recording head is integrally configured to be separable. The liquid supply system according to claim 13, wherein the plurality of communication paths are located substantially higher than the liquid supply path in the vertical direction in a posture during use, and the liquid storage unit is configured to be the liquid storage unit. An ink jet recording apparatus, wherein recording is performed while holding the liquid supply system so as to be positioned substantially higher than a plurality of communication paths. An ink jet recording head for performing recording by discharging ink as a liquid, wherein the liquid communication structure according to any one of claims 1 to 4 is integrally provided. 17. The ink jet recording head according to claim 16, wherein the ink jet recording head has a form of a cartridge detachable from the ink jet recording apparatus. 5. A cartridge which forms the liquid storage portion connected to the liquid communication structure according to claim 1 and is connectable to the liquid communication structure via the plurality of communication passages. Liquid tank. A liquid tank having a form of a cartridge connectable to the liquid communication structure of the ink jet recording head according to claim 16 or 17 through the plurality of communication paths.

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