JP2003053985A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To replace a filter for closing an air suction vent made in an ink tank easily at a low cost. SOLUTION: A vent is made in a subtank 2 connected with a recording head 1 and fixed with a filter holding member 9 having a filter 8 for closing it. A main tank 4 is connected with the subtank 2 and a pump 12 is connected with a fixing member 9. The filter 8 comprises a porous film passing air but not passing ink under normal pressure and passing both air and ink only under a pressure difference of a specified level or above. A member 9 for holding the filter 8 is secured by driving the threaded part into the subtank 2. When the filter 8 deteriorates, the filter holding member 9 is turned and unscrewed and a new filter 8 is held by the filter holding member 9 thus replacing the filter easily at a low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus having an ink tank for storing ink, and more particularly to an inkjet recording apparatus for recording by an inkjet method.

[0002]

2. Description of the Related Art An ink jet recording apparatus is a so-called non-impact type recording apparatus, and has an advantage that it can perform high-speed recording and recording on various recording media and that noise during recording hardly occurs. And is widespread. Such an ink jet recording apparatus ejects minute ink droplets from minute nozzles to record on a recording medium. Generally, a recording head having nozzles for ejecting ink droplets and a recording head are provided. And an ink tank for holding the ink to be used.

Bubbles may accumulate in the ink tank as the recording operation is repeated. In that case,
The pressure balance between the recording head and the ink tank may be lost, and desired ink ejection or ink supply operation may become difficult. Therefore, there is a configuration in which a vent hole is provided in the ink tank and air is sucked from the vent hole by a pump at an appropriate timing to prevent the retention of air bubbles.
Then, in order to prevent the ink inside the ink tank from leaking out due to vibration, posture changes, temperature or pressure changes, etc., we propose a structure that blocks the ventilation holes with a filter made of a porous membrane with many minute holes. Has been done.

As an example, Japanese Patent Laid-Open No. 5-124214
In the ink tank disclosed in Japanese Patent Publication No.
As shown in FIG. 0, a filter 101 made of a hydrophilic porous film or the like is fixed so as to close the ink supply port 103 of the ink tank 102 by ultrasonic welding or adhesion using an adhesive. Since the filter 101 is hydrophilic and the ink tank 102 is filled with ink and air, the filter 101 allows the ink to pass therethrough only during a predetermined suction operation, and the ink leaks to the outside due to normal vibration or posture change. It is a configuration that does not issue.

On the other hand, there is an ink jet recording apparatus which applies an ink tank having a porous film having a gas-liquid separation function and automatically supplies the ink consumed by the recording operation from the ink tank. In such an ink jet recording apparatus, there are roughly two types of ink supply methods, a continuous supply method and an intermittent supply method.

In the continuous supply system, a sub-tank (ink tank) mounted on a movable carriage for supplying ink to an ink jet recording head and a main tank fixed inside the recording apparatus main body are always connected by a tube or the like. Has been done. The ink supplied from the sub tank to the recording head is replenished from the main tank as needed. However, if air bubbles accumulate in the sub tank due to aging or repeated use, the amount of ink replenished in the sub tank decreases, that is, the ink yield decreases. Therefore,
In order to prevent a decrease in ink yield by removing air bubbles in the sub tank, air is sucked by a pump from a vent hole provided in the sub tank.

In the intermittent supply system, the sub tank mounted on the movable carriage and the main tank fixed to the main body of the recording apparatus are not always connected, but are intermittently connected by a joint or the like as needed. It That is, both ink tanks are connected by a joint at appropriate timing, and the air is sucked by the pump from the vent hole of the sub tank each time, forcibly flowing the ink from the main tank to the sub tank, and the ink to the sub tank Will be replenished.

In any of the above-mentioned methods, in order to prevent the ink from being sucked together with the air when the air is sucked from the ventilation hole, the porous film has a meniscus withstand pressure that does not allow the ink to pass by the negative pressure of the pump. A filter consisting of is attached to the vent. This prevents the ink from leaking out from the vent holes of the sub tanks, so that the ink is not wasted, and even if air is simultaneously sucked from a plurality of sub tanks containing inks of different colors, the inks leak out. The effect that they are not mixed is obtained.

Examples of the material constituting such a gas-liquid separable porous membrane include hydrophilic materials such as polypropylene and polyethylene, as well as polytetrafluoroethylene, polychlorotrifluoroethylene, and tetrafluoroethylene-hexafluoro. Fluorine resins such as propylene copolymers, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, tetrafluoroethylene-ethylene copolymers and the like can be mentioned.

[0010]

However, the conventional ink jet recording apparatus having a filter made of a porous film has the following problems.

The porous film used as the filter of the above-mentioned conventional example has a feature that it allows gas to pass through but does not allow ink to pass under a predetermined pressure difference or less. However, the properties such as hydrophilicity and hydrophobicity may be deteriorated by the ink components due to leaving for a long period of time, repeated pressurization in a state of being in contact with the ink, and the like. As a result, even when the ink is not in contact with the porous film, water and ink components are retained inside or on the surface of the porous film, the air permeability is significantly reduced, the internal pressure of the ink tank rises, air cannot be sucked, and the meniscus In some cases, the withstand voltage became smaller than that in the initial state, and ink could easily leak out.

In any of the conventional constructions, the filter made of a porous film is directly fixed to the ink tank by a method such as heat welding, ultrasonic welding, or adhesion with an adhesive. When an expensive recording head is integrally formed or the ink tank is fixed to the main body of the recording device, when a user (user) or service person (maintenance worker) replaces the porous film. However, a complicated disassembling operation is required and an extra cost is required.

Therefore, an object of the present invention is to provide an ink jet recording apparatus in which a filter made of a porous film can be replaced easily and at low cost.

[0014]

A feature of the present invention is an ink jet recording apparatus having a recording head for ejecting ink onto a recording medium and an ink tank for supplying the ink to the recording head, which is provided in the ink tank. At least one vent hole, a filter that allows air to pass therethrough but does not allow ink to pass at a predetermined pressure difference or less, and a filter holding member to which the filter is fixed. It is mechanically attachable to and removable from the ink tank so as to close the pores.

The filter holding member may have a screw portion that can be screwed into the ink tank. The filter holding member may be attached to the ink tank by press fitting. Further, the filter holding member may be attached to the ink tank using screws. Then, it is preferable that the filter holding member is attached so as to be easily and manually removable from the ink tank.

Another feature of the present invention is an ink jet recording apparatus having a recording head for ejecting ink onto a recording medium and an ink tank for supplying ink to the recording head, and at least provided in the ink tank. 1
It has two vents and a filter that allows air to pass but does not allow ink to pass below a predetermined pressure difference.
It is fixed to the ink tank so as to block the ventilation hole, and with the filter fixed, the ink tank can be easily separated manually from both the recording head and the recording device main body and can be removed alone. It is in.

It may have a carriage on which the recording head and the ink tank are mounted, and the carriage, the recording head and the ink tank may be integrally reciprocally movable.

The ink tank may further include a main tank that continuously supplies ink to the ink tank according to the amount of ink supplied to the recording head. Alternatively, the ink tank may further include a main tank that supplies ink to the ink tank non-continuously and selectively according to the amount of ink supplied to the recording head.

A supply number counting means for counting the number of times the ink is supplied from the main tank to the ink tank may be further provided. Further, it may further include a contact time detecting means for detecting a time when the ink contacts the filter.
Further, a flow rate detecting means for detecting the flow rate of air passing through the filter per unit time may be further provided. Also,
A recording number counting means for counting the number of recordings by the recording head may be further provided.

Further, it is preferable to further include control means for executing an operation of prompting replacement of the filter when it is judged that the deterioration of the filter has progressed. Further, a plurality of ink tanks may be provided, and the control unit may be configured to independently judge the degree of deterioration of the filter of each ink tank.

According to this structure, long-term storage,
Alternatively, if there is a possibility that adverse effects such as an increase in internal pressure of the ink tank, inability to suck air, or leakage of ink may occur due to repeated pressurization while the ink is in contact with the porous film, the user (use Person) or a service person (maintenance worker) can easily replace the filter, and it is possible to easily prevent the above-mentioned harmful effects. Also, the cost for that can be minimized.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIGS. 1 to 3 are schematic views of an ink jet recording apparatus according to a first embodiment of the present invention.

The ink jet recording apparatus of this embodiment is
It has a main tank 4 fixed to a frame (not shown) of the recording apparatus main body, and a carriage (not shown) capable of reciprocating inside the recording apparatus. The carriage has a recording head 1 and a sub tank (ink tank).
2 and are installed. Main tank 4 and sub tank 2
Are connected via an ink supply tube 6 and a supply valve 7.

The recording head 1 has a plurality of nozzles 1a and can eject minute droplets of ink from each nozzle 1a. The sub tank 2 has a space for storing ink to be supplied to the recording head 1. The internal space of the sub tank 2 and the ink flow path of the recording head 1 communicate with each other via a dustproof filter 3. The sub tank 2 is provided with a ventilation hole, and a filter holding member 9 holding the filter 8 is attached so as to close the ventilation hole, which will be described later. Sub tank 2 and filter holding member 9
The mounting portion of is sealed by a sealing material 10 such as an O-ring. Further, the pump 12 fixed to the main body of the recording apparatus is provided with an air suction tube 11 and a suction valve 1.
It is connected to the filter mounting member 9 via 3. Inside the main tank 4, a compressed sponge 5 that holds the ink so that it does not flow out is loaded. The fixed main tank 4 and pump 12 are fixed.
And the sub-tank 2 on the moving carriage are connected by a flexible ink supply tube 6 and an air suction tube 11 each having a sufficient length,
It does not hinder the movement of the carriage.

The filter 8 is made of a porous film having a large number of fine pores and allows air to pass therethrough, but does not allow liquids such as water and ink to pass under normal pressure. The filter 8 permits passage of not only air but also liquids such as water and ink only when a pressure difference of a predetermined value or more occurs. The filter 8 is firmly fixed to the filter holding member 9 by heat welding, ultrasonic welding, adhesive bonding, or the like. A male screw portion is formed on the filter holding member 9, a female screw portion is formed on the inner wall of the vent hole of the sub tank 2, and the filter holding member 9 is fixed by being screwed into the sub tank 2.

Next, the operation of the ink jet recording apparatus of this embodiment will be described.

In the ink jet recording apparatus of this embodiment, although not shown, a recording medium such as paper is intermittently conveyed by a conveying mechanism, and the carriage reciprocates correspondingly so as to cross the front of the recording medium. Specifically, the movement of the recording medium for each line (sub-scanning) and the reciprocating movement of the carriage in the direction intersecting with it (main scanning) are alternately performed. An image is formed on the recording medium by ejecting an ink droplet from the nozzle 1a of the recording head 1 to the recording medium at an appropriate timing according to the recording signal. In the present specification, characters, figures, patterns, and the like, regardless of their meaning, are collectively referred to as “image”.

When the image is formed in this way, the supply valve 7 is open and the suction valve 13 is closed, as shown in FIG. Then, as ink is ejected from the nozzles 1 a of the recording head 1 and the ink in the nozzles 1 a is consumed, the ink in the sub tank 2 is supplied to the recording head 1 via the dustproof filter 3. As a result, a negative pressure is generated in the sub tank 2, and the sub tank 2 is sucked through the ink supply tube 6 in the main tank 4.
Since the sponge 5 in the main tank 4 adjusts the pressure of the ink supply path and the nozzle 1a receives a negative pressure by the sponge 5, the meniscus of the nozzle 1a is not broken and the ink does not drip. In this way, the recording head 1 forms an image by ejecting ink while ink is supplied from the main tank 4 via the sub tank 2 as needed.

When this ink jet recording apparatus is used for a long period of time or when temperature change and pressure change are repeatedly applied, bubbles generated in the nozzle 1a, air invading from the surface of the ink supply tube 6, ink The gas and the like decomposed by the may be accumulated in the sub tank 2. If air is accumulated in the sub tank 2, the pressure balance of the ink supply path may be disturbed, and proper ink ejection and ink supply may not be performed. Therefore, in order to remove the air accumulated in the sub tank 2, the following operation is periodically performed in the inkjet recording apparatus of the present embodiment.

As shown in FIG. 2, the pump 12 is driven in a state where the surface of the nozzle 1a is sealed by the cap 14 and the suction valve 13 is opened. Then, as shown by the arrow, air is drawn out through the filter 8, and the ink flows into the sub tank 2 from the ink supply tube 6 by that amount, and the liquid level in the sub tank 2 rises. Then, as shown in FIG. 3, when the raised liquid surface covers the surface of the filter 8, the ink is not drawn even if sucked by the pump 12, and the internal pressure in the air suction tube 11 only decreases. . When the maximum negative pressure generated by the pump 12 is P0, and the maximum pressure difference (predetermined value) at which the porous film forming the filter 8 does not pass ink is P1,
The combination of the performance, material, and type of the pump 12, the filter 8, and the ink is preset so that the relationship of P1> P0 is established.

By the air suction operation described above, it is possible to prevent the amount of air in the sub-tank 2 from increasing so that the ink supply is interrupted or the thermal expansion of the air causes a harmful effect. However, during repeated suction of air, the air permeability may deteriorate due to clogging or wetting of the filter 8. That is, if the ink is allowed to pass through the filter 8 even if the pressure is equal to or lower than the predetermined value P1, the ink is also sucked out in the air suction operation described above, and as a result, the sub-tank 2 and the recording head. 1 cannot be maintained at an appropriate pressure, and the desired ink ejection and ink supply cannot be performed, which may lead to defective image formation. If the surface of the filter 8 is always wet with ink, the air in the sub tank 2 may not be extracted even at the maximum pressure P0 of the pump. Therefore, after stopping the operation of the ink jet recording apparatus, the performance is restored by replacing the filter 8 with a new one.

In the ink jet recording apparatus of the present embodiment shown in FIGS. 1 to 3, as described above, the filter holding member 9 to which the filter 8 is fixed is screwed and fixed to the sub tank 2. Therefore, after the user (user) or the service person (maintenance worker) removes the air suction tube 11 from the filter holding member 9, the filter holding member 9
The filter 8 and the filter holding member 9 can be easily removed from the sub tank 2 by rotating the and relative to the sub tank 2 and releasing the screwing. Further, the new filter 8 and the filter holding member 9 can be easily attached by the user (user) or the service person (maintenance worker) rotating the filter holding member 9 relative to the sub tank 2. Thus, in this embodiment, the filter 8 can be easily replaced by attaching and detaching the filter 8 together with the filter holding member 9.

The sub-tank 2 of the filter holding member 9
Various modifications can be considered as a method of attaching to. For example, as shown in FIG. 4, a method of fastening the outer peripheral portion of the filter holding member 19 to the sub tank 21 with a screw 15 or a method of pressing the filter holding member 29 into the vent hole of the sub tank 22 as shown in FIG. 5 is possible. . Further, although not shown, a filter holding member formed by outsert-molding an elastomer around the filter 8 may be sandwiched from above and below by a fixing member and sealed. It is preferable that a user or a service person can easily manually remove the filter holding members 9, 19, 29 from the sub tanks 2, 21, 22. Of course, when the filter holding members 9, 19, 29 are attached to the sub tanks 2.21, 22, they are firmly sealed so that air and ink do not leak.

Further, the filter holding member 9 of the filter 8,
The fixing method to 19, 29 is not limited to the above-mentioned heat welding, ultrasonic welding, and adhesion with an adhesive, and various methods can be changed.

When a plurality of colors of ink are used as in a color printer, the main tank 4 is also used as the sub tank 2,
A plurality of 21, 22 are also provided, but even in this case, it is possible to take a completely similar configuration. In that case, by combining the filter holding members 9, 19, and 29 into one and fixing a plurality of filters 8 to the single filter holding member 9, 19, and 29, all the sub tanks 2, 2
It is also possible to replace the filters 8 of 1 and 22 at a time. Of course, on the contrary, it is also possible to provide the filter holding members 9, 19, 29 for each of the sub-tanks 2, 21, 22 so that all of them can be replaced independently.

Other various modifications are possible,
A filter holding member 9 for holding the porous membrane filter 8;
It does not deviate from the gist of the present invention as long as 19, 29 can be easily replaced.

[Second Embodiment] Next, a second embodiment of the present invention will be described. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

6 to 8 are schematic views of a recording apparatus according to the second embodiment of the present invention.

In the first embodiment, the continuous supply system in which new ink is continuously supplied according to the ink ejected from the recording head 1 is adopted, but in the present embodiment, the new ink is selectively and intermittently supplied. An intermittent supply system in which ink is supplied is adopted.

The ink jet recording apparatus of this embodiment is
As in the first embodiment, the fixed main tank 4
And a carriage (not shown) capable of reciprocating. A holder 36 is mounted on the carriage. The holder 36 is in the shape of a hollow container, the recording head 1 is disposed outside the holder 36, and the sub tank (ink tank) 20 is accommodated inside the holder 36.
The recording head 1 is attached to the holder 36,
It is in close contact with the sub-tank 4 inside the holder 36 via the dustproof filter 3. The sub tank 20 has a holder 36.
After being inserted into, the sub-tank fixing lever 32 swingable around the fulcrum 23 is pressed and fixed from above. In addition, in this way, the sub tank 20
When fixing the sub tank fixing lever 32,
It is locked and fixed to the engaging claws of the holder 36.

An opening is provided on the bottom surface (lower surface) of the ink holding space of the sub tank 20, and the dustproof filter 3 is fixed so as to close the opening. Then, with the sub-tank 20 attached to the holder 36,
The nozzle 1a is connected to the sub tank 2 through the dustproof filter 3.
The recording head 1 is attached to the holder 36 so as to communicate with 0.

The sub-tank 20 is formed with a vent hole which is bent downward from the upper surface thereof. The filter 8 made of a porous film is directly fixed to the inner wall of the sub tank 20 by ultrasonic welding or the like, and the filter 8 closes one end of the vent hole. Similar to the first embodiment, the filter 8 is made of a porous film having a large number of fine pores and allows air to pass therethrough, but does not allow liquids such as water and ink to pass therethrough at normal pressure and has a predetermined value. Only when the above pressure difference occurs, passage of not only air but also liquids such as water and ink is allowed.

Further, another opening is provided on the bottom surface (lower surface) of the ink holding space of the sub tank 20, and the joint rubber 35 is press-fitted and fixed in this opening. The joint rubber 35 has fine slits penetrating the joint rubber 35. However, as shown in FIG. 6, the slits are normally closed by being tightly closed by the elastic force of the joint rubber 35 itself. Cage,
Only when the slit is pushed open with a needle, etc., communicates vertically. The sub-tank sponge 31 is press-fitted inside the sub-tank 20, that is, in the space for storing ink.

A joint cap 37 that moves up and down in conjunction with a joint needle 34, which will be described later, is provided at a position facing the outlet of the vent hole when the carriage is at the home position.
Is provided. The joint cap 37 is connected to the pump 12 via the air suction tube 11.
A pressure gauge 33 is provided in the middle of the air suction tube 11.

A vertically movable joint needle 34 is provided at a position facing the joint rubber 35 when the carriage is at the home position. Joint needle 3
4 is connected to the main tank 4 via an ink supply tube 6 and a supply valve 7. As shown in FIG. 6, when the joint needle 34 is not inserted into the joint rubber 35, the supply valve 7 is closed in order to prevent ink from leaking from the main tank 4.

Next, the operation of the ink jet recording apparatus of this embodiment will be described.

Similar to the first embodiment, the movement of the recording medium line by line (sub-scanning) and the reciprocating movement of the carriage in the direction intersecting with it (main scanning) are alternately performed, and the carriage is moved. Sometimes, the recording head 1 at an appropriate timing
Ink droplets are ejected from the nozzle 1a on the recording medium to form an image. During this image forming operation, as shown in FIG. 6, the joint rubber 35 is in a closed state without the joint needle 34 being inserted. Therefore, new ink is supplied from the sub tank 20 to the recording head 1 in accordance with the ink ejected from the nozzles 1a of the recording head 1, but the ink held in the sub tank sponge 31 is not replenished, and the ink and air are The liquid level in the sub tank sponge 31 is gradually lowered by the replacement.

When the amount of ink used by the recording head 1 reaches a predetermined amount, the carriage is once returned to the home position and, as shown in FIG.
The joint needle 34 moves upward and pierces the joint rubber 35 to communicate with the ink supply path. At the same time, the joint cap 37 is closely attached so as to cover the vent hole of the sub tank 20.

Next, the supply valve 7 is opened and the pump 12
7, the air in the sub tank sponge 31 is drawn out through the air suction tube 11, and new ink is supplied from the main tank 4 to the sub tank 20 through the ink supply tube 6 as shown by the arrow in FIG. Then, when the liquid level in the sub tank 20 rises to completely cover the filter 8 as shown in FIG. 8, it is no longer possible to suck air any more, and the internal pressure in the air suction tube 11 decreases. As in the first embodiment, P1 is the maximum negative pressure generated by the pump 12, and P1 is the maximum pressure difference (predetermined value) at which the porous film forming the filter 8 does not allow ink to pass. P1> P0 The combination of the performance, material, and type of the pump 12, the filter 8, and the ink is set in advance so that the above relationship holds.

When the air suction operation described above is repeated,
Similar to the first embodiment, the air permeability may be deteriorated due to clogging or wetting of the filter 8, and an appropriate air suction operation may not be performed, and desired ink ejection and ink supply may become impossible.

In this embodiment, the control means 51 for controlling the ink jet recording apparatus determines the degree of progress of deterioration of the filter 8. FIG. 9 schematically shows the control system of this ink jet recording apparatus.

The control means 51 is controllably connected to an operation panel 52, a controller 53 for exchanging information with an external device, a motor for driving a carriage and a paper feed roller (not shown), a buzzer 55 and the like. Together with the supply number coefficient means 23 and the contact time detection means 24
Further, the flow rate detecting means 25, the detecting means such as the recording number coefficient means 26, etc. are connected. Then, based on the input signal from the supply number coefficient means 23, the control means 51 determines the number of times the ink is supplied from the main tank 4 to the sub tank 12 by the method described above, based on the input signal from the contact time detection means 24. After the ink is supplied, the amount of time that the sub-tank 2 is left in a state of being filled with the ink,
5, the sub tank 2 is filled with ink after the suction by the pump 12 is started based on the input signal from the pressure gauge 33.
Based on an input signal from the recording number coefficient means 26, the amount of ink ejected by the recording head 1 or the number of printed sheets is calculated and stored as the air suction time until the degree of negative pressure detected by the method is increased. . And the control means 51
Determines that the filter 8 has deteriorated under the following conditions, and implements an operation to prompt the user to replace it.

Condition 1: Main tank 4 to sub tank 2
When the number of times of ink supply to 0 reaches a predetermined value Condition 2: When the sub tank 20 is filled with ink, that is, when the accumulated time of the state where the ink is in contact with the filter 8 reaches a predetermined value Condition 3: Sub tank Filter 8 when ink is supplied to 20
V is the flow rate of the air passing through, that is, the ink volume consumed by the recording head 1 from the time when the sub-tank 20 was previously filled with ink, and the sub-tank 20 starts to suck again after the pump 12 starts suctioning. When the value of V / T becomes smaller than a predetermined value, where T is the time until the degree of the negative pressure detected by the pressure gauge 33 is increased, the condition 4: By the recording head 1. When the ink ejection amount or the number of printed sheets reaches a predetermined value, the control device determines that the filter 8 has deteriorated and issues a warning operation when at least one of the above conditions 1 to 4 is detected. As the warning operation, for example, lighting of an LED provided on the operation panel 52, ringing of a buzzer 55, display of a warning message to a computer or an external device through the controller 53, or suspension of the printing operation by stopping the motor 54 is performed. Various methods are possible.

In response to this warning operation, a user or a service person stops the operation of the ink jet recording apparatus and then replaces the filter 8 with a new one to restore its performance. In the present embodiment, the sub-tank fixing lever 32 is pulled up, and the sub-tank 20 is pulled out from the sub-tank holder 36 for replacement. As a result, it is not necessary to replace the precise and expensive recording head 1 at the same time, and wasteful cost can be reduced. Further, in the present embodiment, when replacing the sub-tank 20, it is not necessary to remove or reconnect the tubes.

When a plurality of colors of ink are used as in a color printer, the main tank 4 and the sub tank 20 are also used.
Although a plurality of units are provided, the same configuration can be adopted in this case as well. If the deterioration of the filter 8 is determined for each sub-tank 20 for each color by managing the number of times of ink supply for each color, the leaving time, the ejection history of the recording head 1, and the like, the accuracy of replacement timing can be improved and extra. It is possible to avoid unnecessary replacement. The method of determining the deterioration of the filter 8 is not limited to the example of the above-described embodiment, and various methods such as usage time, history of temperature change, history of pressure change, and number of times of replacement of the main tank 4 can be considered. The sub-tank 20 to which the filter 8 of the porous film is fixed can be easily replaced independently of the recording head 1 or the like without departing from the gist of the present invention.

[0057]

According to the present invention, when the filter is deteriorated, the user or service person can easily replace it. Therefore, it is possible to prevent adverse effects such as increase in internal pressure of the ink tank, inability to suck air, and leakage of ink due to repeated pressurization while the ink is in contact with the filter. Since various air suction operations can be performed, desired ink ejection and ink supply can be maintained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an inkjet recording device according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing an air suction operation of the ink jet recording apparatus according to the first embodiment.

FIG. 3 is a schematic cross-sectional view showing an air suction operation of the ink jet recording apparatus according to the first embodiment.

FIG. 4 is a schematic cross-sectional view of another example of the inkjet recording apparatus according to the first embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of still another example of the inkjet recording apparatus according to the first embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view of an inkjet recording device according to a second embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view showing an air suction operation of the ink jet recording apparatus according to the second embodiment.

FIG. 8 is a schematic cross-sectional view showing an air suction operation of the ink jet recording apparatus according to the second embodiment.

FIG. 9 is a schematic block diagram showing a control system of the inkjet recording apparatus of the second embodiment.

FIG. 10 is a cross-sectional view of an ink tank of a conventional inkjet recording device.

[Explanation of symbols]

1 recording head 1a nozzle 2 Sub tank (ink tank) 3 Dust filter 4 main tank 5 sponge 6 Ink supply tube 7 supply valve 8 filter (porous membrane) 9 Filter holding member 10 Seal material 11 Air suction tube 12 pumps 13 Suction valve 14 cap 15 screws 19 Filter holding member 20, 21, 22 Sub tank (ink tank) 23 Supply frequency coefficient means 24 Contact time detection means 25 Flow rate detection means 26 Recording Number Coefficient Means 29 Filter holding member 31 Sub tank sponge 32 Sub tank fixing lever 33 Pressure gauge 34 joint needle 35 joint rubber 36 holder 37 Joint Cap 51 control means 52 Operation panel 53 Controller 54 motor 55 buzzer

Claims (15)

[Claims] 1. An inkjet recording apparatus comprising a recording head for ejecting ink onto a recording medium and an ink tank for supplying the ink to the recording head, wherein at least one ventilation hole is provided in the ink tank. , A filter that allows air to pass but does not allow ink to pass at a predetermined pressure difference or less, and a filter holding member to which the filter is fixed, wherein the filter holding member is configured such that the filter blocks the vent hole. An ink jet recording apparatus, which is mechanically attachable to and removable from the ink tank. 2. The ink jet recording apparatus according to claim 1, wherein the filter holding member has a screw portion that can be screwed into the ink tank. 3. The ink jet recording apparatus according to claim 1, wherein the filter holding member is attached to the ink tank by press fitting. 4. The ink jet recording apparatus according to claim 1, wherein the filter holding member is attached to the ink tank with a screw. 5. The filter holding member is manually and easily detachably attached to the ink tank.
The inkjet recording apparatus according to claim 1. 6. An ink jet recording apparatus having a recording head for ejecting ink onto a recording medium and an ink tank for supplying the ink to the recording head, wherein at least one vent hole provided in the ink tank. A filter that allows air to pass through but does not allow ink to pass below a predetermined pressure difference, the filter is fixed to the ink tank so as to block the vent hole, and the ink tank is fixed to the filter. In this state, the inkjet recording apparatus is characterized in that it can be manually and easily separated from both the recording head and the recording apparatus main body and detached as a single unit. 7. The carriage according to claim 1, further comprising a carriage on which the recording head and the ink tank are mounted, and the carriage, the recording head, and the ink tank can integrally reciprocate. Inkjet recording apparatus according to the item. 8. The ink jet recording apparatus according to claim 7, further comprising a main tank that continuously supplies ink to the ink tank in accordance with the amount of ink supplied to the recording head. 9. The inkjet recording according to claim 7, further comprising a main tank that supplies ink to the ink tank discontinuously and selectively according to the amount of ink supplied to the recording head. apparatus. 10. The ink jet recording apparatus according to claim 9, further comprising a supply number counting means for counting the number of times the ink is supplied from the main tank to the ink tank. 11. A contact time detection unit for detecting a time when ink is in contact with the filter is further provided.
10. The inkjet recording device according to any one of items 10 to 10. 12. The ink jet recording apparatus according to claim 1, further comprising a flow rate detecting unit that detects a flow rate of air passing through the filter per unit time. 13. The ink jet recording apparatus according to claim 1, further comprising recording number counting means for counting the number of recordings by the recording head. 14. The ink jet recording apparatus according to claim 1, further comprising a control unit that executes an operation of prompting replacement of the filter when it is determined that the deterioration of the filter has progressed. 15. The ink jet recording apparatus according to claim 14, wherein a plurality of the ink tanks are provided, and the control unit independently judges the deterioration degree of the filters of the ink tanks.