JP2002200771A - Ink jet recording device - Google Patents

Abstract

(57) [Problem] To prevent clogging of a filter in an ink jet recording apparatus provided with an ink circulation system for collecting waste ink discharged from an ink jet head through a filter into a sub tank and reusing the same. SOLUTION: In an ink jet recording apparatus 1, a head cap 9 ejected from an ink jet head 2 is ejected.
The collected waste ink is collected by the ink collection unit 12 formed in the sub tank 7 and then filtered by the filter 14 and then collected by the ink storage unit 13. The ink recovery unit 12 communicates with a waste ink tank 16 via a discharge path 15, and when the discharge pump 17 is driven, the waste ink in the ink recovery unit 12 is discharged together with foreign matters such as dust accumulated therein. . At the same time, the ink in the ink reservoir 13 flows backward through the filter 14 and is discharged, so that dust and the like trapped therein are washed away. Therefore, clogging of the filter can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus provided with an ink circulating system for collecting waste ink discharged from an ink jet head and reusing the same through a filter, and more particularly, to an ink jet recording apparatus capable of preventing filter clogging. It relates to a recording device.

[0002]

2. Description of the Related Art An ink jet recording apparatus performs printing by supplying ink from an ink tank to an ink jet head and discharging ink droplets from each ink nozzle of the ink jet head onto a recording medium.
Since the diameter of the ink nozzle is small, if ink characteristics are deteriorated or bubbles are mixed in the ink nozzle, adverse effects such as clogging of the ink nozzle and printing of missing dots occur.

Therefore, conventionally, a head cleaning operation for forcibly sucking ink and air bubbles in an ink jet head to the outside by using a pump before starting printing or during a printing pause period, and wasting ink droplets from ink nozzles. An ink nozzle reproducing operation for hitting is performed.

Here, when such a cleaning operation or a reproducing operation is performed, a large amount of ink that does not contribute to actual printing is wasted, and the life of the ink tank is shortened. To avoid such adverse effects, for example,
Japanese Patent Application Laid-Open No. 10-2111718 discloses an ink circulation system in which ink droplets ejected from an ink-jet head are collected once, recovered by a recovery pump, filtered through a filter, and then returned to a sub-tank.
The sub-tank is supplied with ink from the ink tank so that the liquid level is always equal to or higher than a certain level, and the ink supply pressure to the inkjet head is kept constant.

[0005]

However, the ink is supplied from the ink tank to the ink jet head via the sub tank, the waste ink discharged from the ink jet head is collected, filtered through a filter, and then collected in the sub tank. When employing an ink circulation system designed to be reused, there are the following problems. When the ink is used for a long time or when the ink jet recording apparatus is used in an environment where there is much dust, the filter is clogged. As a result, the pressure in the waste ink passage on the front side of the filter increases, and problems such as ink leakage occur. In order to avoid such an adverse effect, the filter needs to be replaced frequently, which is bothersome and maintenance costs are high.

Here, in order to reduce the frequency of filter replacement, it is conceivable to circulate the ink using a high-performance pump. However, this is not realistic because the pressure of the waste ink passing through the clogged filter is further increased, and damage such as ink leakage is further increased.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to propose an ink jet recording apparatus having an ink circulation system capable of avoiding clogging of a filter.

[0008]

In order to solve the above-mentioned problems, the present invention provides an ink tank, an ink jet head, and ink supplied from the ink tank at a predetermined supply pressure to the ink jet head. An ink jet recording apparatus comprising: a sub-tank; and a filter for removing dust and the like from waste ink discharged from the ink-jet head, wherein the waste ink after passing the filter is returned to the sub-tank. And a waste ink tank that collects the waste ink collected by the ink collection unit without passing through the filter. .

According to the present invention, when collecting the waste ink collected in the ink collecting section into the waste ink tank, dust and the like trapped in the filter communicating with the ink collecting section are removed together with the waste ink. Collected in tank. Therefore, if this collection operation is performed, for example, periodically, clogging of the filter can be prevented.

In a typical configuration of the present invention, there is provided a discharge pump for discharging the waste ink recovered in the ink recovery section to the waste ink tank, and the recovery operation may be performed by the discharge pump.

Further, a detecting means for detecting that the ink supplied from the ink tank to the sub-tank has exceeded a use limit, and a control circuit for driving and controlling the discharge pump in accordance with the detection result of the detecting means. If the configuration having the above configuration is adopted, the collection operation can be performed when the ink exceeds the usage limit.

Next, the ink recovery section may be formed in the sub-tank. In this case, the ink storage section and the ink recovery section may be communicated via the filter.

Here, the sub-tank is provided with a vent opening to the atmosphere in order to discharge bubbles entering the ink circulation system and stabilize the ink supply pressure supplied to the ink jet head. In this case, the ink reservoir is
An ink supply chamber communicating with the ink tank and the ink jet head, and an air opening chamber formed with a vent are provided, and the space between the ink supply chamber and the air opening chamber is more than the filter. It is desirable that the communication be established via a fine second filter, and that the air opening chamber and the ink recovery unit be communicated via the filter.

With this configuration, it is possible to prevent the bubbles contained in the waste ink collected in the ink collecting section from entering the ink storage section, which is the ink supply side, by using the second filter. Can be blocked by

Further, in this case, the ceiling surface of the ink supply chamber is inclined upward toward the air opening chamber, and the upper surface of the ceiling surface is provided with a partition between the ink supply chamber and the air opening chamber. It is desirable to arrange a second filter.

If this configuration is adopted, air bubbles that have entered the sub-tank from the ink tank at the time of initial filling of ink and the like are quickly moved to the side of the air opening chamber along the inclined ceiling surface, and the air opening is reduced. It can be discharged to the outside from the vent of the room.

Next, a cartridge type ink tank can be adopted as the ink tank.

In this case, a cartridge having the waste ink tank may be used as the cartridge type ink tank.

On the other hand, in the present invention, the detecting means comprises:
It may be configured to detect whether or not the ink in the ink tank has exceeded a usage limit based on an elapsed time after the ink tank replacement.

The detecting means may be configured to detect whether or not the ink in the ink tank has exceeded a use limit based on the amount of waste ink collected in the waste ink tank after replacing the ink tank. can do.

Further, the detecting means may be configured to detect whether or not the ink in the ink tank has exceeded a use limit based on a change in ink characteristics.

In this case, the change in the ink characteristics includes a change in ink density or ink viscosity.

Next, in a typical configuration of the present invention, in addition to the above-described discharge pump, a recovery pump for recovering waste ink discharged from the ink jet head to the ink recovery unit, and a recovery pump for recovering waste ink from the ink tank are provided. A supply pump that supplies ink to the sub-tank; and a liquid level sensor that detects an ink level in the sub-tank.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ink jet recording apparatus to which the present invention is applied will be described below with reference to the drawings.

FIG. 1 is a schematic structural view showing a main part of the ink jet recording apparatus of this embodiment. The ink jet recording apparatus 1 of the present embodiment includes an ink jet head 2 of an electrostatic drive type. Ink is supplied to the ink jet head 2 from an ink tank 4a formed in an ink cartridge 4 removably mounted on the ink cartridge mounting section 3. That is, the ink is supplied to the sub tank 7 by the ink supply pump 6 (P1) via the ink supply path 5 connected to the ink supply port 4b of the ink tank 4a in the ink cartridge 4 mounted on the ink cartridge mounting section 3. Supplied. The ink stored in the sub tank 7 is supplied to the ink jet head 2 via an ink supply path 8 communicating with the bottom surface.

The ink jet head 2 has a plurality of ink nozzles, and moves the ink jet head 2 to a position facing the head cap 9 located at a position outside the printing range during the cleaning operation and the reproducing operation of these nozzles. , The ink droplets into the head cap 9
The ink is ejected toward the waste ink absorber 9a held in the printer. In addition, as a nozzle cleaning operation, the head cap 9 is
There is also a suction operation in which ink is forcibly sucked from each ink nozzle over the nozzle surface 2a, and the ink droplets sucked in this case are also absorbed by the ink absorber 9a. Such cleaning and regenerating operations of the nozzle are well-known, and further description will be omitted.

The waste ink absorbed by the waste ink absorber 9a of the head cap 9 is transferred to an ink recovery section 12 via an ink recovery path 11, which is a waste ink path to which a waste ink pump 10 (P2) is connected. Collected.

Here, the ink recovery section 12 of the present embodiment is formed inside the sub tank 7. That is, the inside of the sub tank 7 is partitioned into an ink storage unit 13 for storing ink supplied from the ink tank 4 and an ink recovery unit 12. Between these, ink can be circulated through the filter 14. Therefore, the waste ink collected by the ink collecting unit 12 is filtered through the filter 14 and then returned to the ink storing unit 13 and can be reused.

A waste ink discharge path 15 is connected to the ink recovery section 12. The other end of the ink discharge path 15 is connected to a waste ink section (waste ink tank) 16 formed in the ink cartridge 4. It is connected. By driving the discharge pump 17 connected to the waste ink discharge path 15, the waste ink collected by the ink recovery unit 12 can be directly discharged to the waste ink unit 16 without passing through the filter 14.

Here, a vent 18 to which a solenoid valve 19 is attached is formed on the ceiling surface of the ink reservoir 13 in the sub-tank 7. In addition, the ink storage unit 13
Two liquid level sensors 21 and 22 for detecting whether or not the liquid level of the ink accumulated in the liquid is equal to or higher than the level L1 and the level L2 higher than the level L1 are attached. The liquid level of the sub-tank 7 is always maintained at the level L2 or higher, and when the liquid level becomes lower than L1, it is detected that there is no ink. In this example, the liquid level L1 is set at a position substantially equal to the height of the filter 14.

In the ink supply path 8 between the sub-tank 7 and the ink jet head 2, a detector 23 for detecting whether or not the ink flowing through the ink supply path 8 is at a use limit is mounted. The detector 23 of the present example is an ink characteristic detector that detects the ink characteristic. This ink characteristic detector 2
As 3, an ink density sensor and an ink viscosity sensor can be used.

As an ink density sensor, for example, FIG.
A transmission type optical sensor 23A as shown in FIG. In this case, a part of the ink supply passage 8 is set as a transparent passage portion 24, and a transmission type optical sensor 23A is attached thereto, and light is transmitted to the ink flowing therethrough. Ink density can be detected.

As an ink viscosity sensor, for example, FIG.
The differential pressure sensor 23B shown in (b) can be used.
The differential pressure sensor 23 </ b> B
a is formed, ink is caused to flow at a constant flow rate through the thin tube portion 8a by the metering pump 25, and the ink viscosity is detected based on the pressure difference (P1-P2) between both ends of the thin tube. Since the pressure difference increases as the ink viscosity increases, it can be determined that the ink usage limit is reached when the pressure difference exceeds a certain pressure difference.

Next, the ink jet recording apparatus 1 having the above-described configuration includes a control circuit 30 for driving and controlling each part, and the control circuit is mainly composed of a microcomputer. Functions related to the ink circulation system in the control circuit 30 include a solenoid valve 19 for opening and closing a vent.
, A pump control function for driving and controlling the pumps 6, 10, and 17, a discriminating function for discriminating whether or not the ink has exceeded a use limit based on the detector 23, and the like.

The ink supply / discharge operation of the ink jet recording apparatus 1 of the present embodiment realized by the control circuit 30 will be described with reference to the flowchart of FIG. First, in the printing standby state, the control proceeds from step ST2 in accordance with the flow of “YES”, the ventilation port 18 provided in the sub tank 7 is closed by the electromagnetic valve 19, and the moisture of the ink stored in the ink storage unit 13 evaporates. (Step ST1,
2, 3). In a state other than the standby state, the electromagnetic valve 19 is driven to open the air vent 18, and ink pressure fluctuations occurring when ink is replenished to the ink reservoir 13 of the sub-tank 7 and when ink is sucked from the ink reservoir 13 are changed.
(Steps ST4 and ST8).

In the printing state, "YE" is returned from step ST9.
The control proceeds along the flow of "S", and after confirming based on the output of the liquid level sensor 22 that the liquid level of the ink reservoir 13 of the sub tank 7 is equal to or higher than L2, the printing operation is performed. During printing, the drive of the ink supply pump 6 is controlled so that the liquid level is located between L1 and L2 (steps ST10, ST11, ST12).

In the above-described cleaning state of the inkjet head 2, the nozzle surface 2 of the inkjet head 2
a of the ink recovery pump 10
Is driven (steps ST13 and ST14). The waste ink collected in the head cap 9 by the pump 10 passes through the ink collection path 11 to the ink collection unit 1 of the sub tank 7.
Collected in 2. The ink collected in the ink collecting unit 12 is filtered after dust and the like are filtered through a filter 14.
It returns to the ink storage section 13 of the sub tank 7 and is used for reuse. The bubbles contained in the ink returned to the ink storage section 13 of the sub-tank 7 in this way are discharged to the outside through the vent 18 in the open state. Note that, during a recovery operation (flushing) in which ink droplets are ejected from each ink nozzle of the inkjet head 2, the same operation as during cleaning is performed without covering the nozzle surface 2 a of the inkjet head 2 with the cap 9. Will be

Next, when the detector 23 detects that the ink has exceeded the use limit, the operation state is set to the ink discharge state, and the control proceeds from step ST15 to "YE".
The flow proceeds along the flow of “S”, and drives the discharge pump 17.
When the discharge pump 17 is driven, both the ink in the sub-tank 7, that is, the waste ink collected in the ink collection unit 12 and the ink stored in the ink storage unit 13 pass through the discharge pipe 15 and Collected in the waste ink tank 16.

Here, in this ink discharge state,
Dust and the like accumulated in the waste ink inflow side of the filter 14, that is, the dust collected in the ink recovery unit 12, are discharged to the waste ink tank 16 together with the waste ink. At the same time, the ink stored in the ink storage unit 13 is discharged to the waste ink tank 16 through the filter 14, so that the filter 14 is back-washed by the flow of the ink, and dust and the like clogged in the filter 14 are removed. Washed and discharged. As a result, clogging of the filter 14 is eliminated.

When the ink in the ink jet head 2 and the ink in the ink recovery path 11 are also discharged,
The pump 10 may be driven at the same time as the pump 17.

On the other hand, after the ink cartridge 4 has been replaced and a new one has been mounted, at the time of initial filling performed for filling the ink circulation system with ink, control is performed in accordance with the flow of "YES" from step ST1. With the head cap 9 put on the inkjet head 2,
The ink supply pump 6 is driven to supply ink into the ink reservoir 13 of the sub tank 7 until the liquid level reaches L2. Thereafter, the ink recovery pump 10 is driven for a predetermined time, and the inkjet head 2 and the sub tank 7 are driven.
The ink is collected into the ink recovery path 11 communicating with the ink recovery unit 12 of the first embodiment. When the liquid level of the ink reservoir 13 falls below L2 due to this filling, the ink supply pump 6 is driven again to replenish the ink from the ink cartridge 4 into the sub-tank (step ST4,
5, 6, 7, 17, 18).

As described above, in the ink jet recording apparatus 1 of this embodiment, foreign matter such as dust contained in the waste ink collected from the ink jet head 2 is filtered by the filter 1.
4 is once collected in the ink collecting section 12 disposed before the ink collecting section 4. The foreign matter collected here is discharged when the ink stored in the ink storage unit 13 of the sub tank 7 is detected to have exceeded the usage limit when the ink is discharged from the ink storage unit 13. It is discharged outside by the ink. At the same time, foreign matter fields such as dust trapped in the filter 14 are also washed out of the filter 14 and discharged to the outside.

Therefore, according to the present embodiment, a large amount of foreign matter accumulates in the filter 14 and the filter is clogged. As a result, the pressure in the ink recovery path in front of the filter abnormally increases, and ink leakage and the like occur. Can be avoided beforehand.

(Another Example of Subtank) Next, FIG. 4 shows a different configuration example of the subtank 7. In the following description, portions corresponding to the respective portions in the above-described sub-tank 7 are denoted by the same reference numerals, description thereof will be omitted, and only different portions will be described.

First, the sub tank 7A shown in FIG.
Is divided into two parts corresponding to the above-mentioned ink storage section 13 to form an ink supply chamber 13A and an air opening chamber 13B. A vent 18 is provided on the ceiling of the open-to-air chamber 13B.
Is open. In addition, a second filter 41, which is finer than the filter 14, is disposed in a partition part that separates the ink supply chamber 13A from the air release chamber 13B. The ink can be distributed between the spaces.

In the sub-tank 7A configured as described above, the ink collected in the ink collecting section 12 first flows into the open-to-atmosphere chamber 13B through the filter 14, and then passes through the fine filter 41. Ink supply chamber 13
Flow into A. Therefore, bubbles contained in the ink are prevented from entering the ink supply chamber 13A by the fine filter 41 that separates the air release chamber 13B and the ink supply chamber 13A.

Next, the sub tank 7B shown in FIG.
Has a structure basically similar to that of the sub-tank 7A, except that the ceiling surface 42 of the ink supply chamber 13A faces the fine filter 41 separating the ink supply chamber 13A and the open-to-atmosphere chamber 13B. The inclined surface is inclined upward. The vent 18 is located higher than the inclined ceiling surface 42.

In the sub-tank 7B having this configuration, at the time of initial filling of the ink or the like, the air existing in the sub-tank moves smoothly along the inclined ceiling surface 42 and is discharged to the outside from the ventilation port 18. Is done.

(Another Method for Detecting Ink Use Limit) Next, as a method for detecting the ink use limit, the detector 23 for detecting the ink characteristics in the ink supply path 8 as described above is used. Instead of determining the ink usage limit in the control circuit 30 based on the detection result of the detector 23, the following method can be adopted.

The first method is a method for detecting whether or not the ink in the ink tank has exceeded the use limit based on the elapsed time after the replacement of the ink cartridge 4. For this purpose, a sensor for detecting that the ink tank 4 has been replaced and a timer for counting the elapsed time after the ink tank replacement effect may be provided, and the determination may be made based on these outputs and count values. .

In the second method, the ink in the ink cartridge exceeds the usage limit based on the amount of waste ink collected in the waste ink tank 16 after the replacement of the ink cartridge 4 or the amount of ink circulated after the replacement of the ink cartridge. This is a method of detecting whether or not the event has occurred. Here, the ink circulation amount is the amount of ink that has flowed back to the sub-tank 7 through the ink recovery path 11, and can therefore be measured by a flow meter that is partially disposed in the ink recovery path 11 on the discharge side of the ink recovery pump 10. . Instead of this, the ink recovery pump 1
The ink circulation amount may be calculated based on 0 driving time.

Of course, it is also possible to detect the ink usage limit based on both the elapsed time after the ink cartridge replacement and the ink circulation amount. In this case, the ink usage limit can be detected more accurately. It is.

(Other Embodiments) In the above example, an ink cartridge is provided as an ink tank. Instead of the ink cartridge, a fixed ink tank is provided, and ink is replenished therein. It is needless to say that the present invention can be similarly applied to the above-mentioned ink jet recording apparatus.

In the above example, the ink recovery section is formed in the sub-tank. However, as shown in FIG. 5, the ink recovery section 12 is disposed outside the sub-tank 7, and the sub-tank 7 and the ink recovery section are separated. It is also possible to adopt a configuration in which the sections 12 communicate with each other via a filter 14.

Furthermore, in the above example, the waste ink tank is formed in the ink cartridge, but it is of course possible to form the waste ink tank separately.

Next, in the above example, each of the pumps 6, 10,
17 has been described assuming that the inkjet recording apparatus has a backflow prevention function such as a known tube pump. When a pump having no backflow prevention function is used, for example, as shown in FIG. 6, a check valve may be provided in the ink passage portion.

In FIG. 6, V1 is a check valve for preventing the ink in the sub-tank 7 from flowing back into the ink cartridge 4. The installation position is such that the ink supply port is provided so that ink leakage at the time of ink cartridge replacement can be reduced. 4
It is desirable that a is closest to a. V2 is a check valve for preventing the ink in the sub-tank 7 from flowing back to the head cap 9. The installation position is preferably close to the head cap 9 in order to eliminate ink leakage when the head cap is opened. . V3 is a control valve for preventing the ink in the sub tank 7 from flowing down to the ink cartridge 4. In the control valve V3, ink flows when the pump 17 is driven and the pressure in front of the control valve V3 is high, but ink does not flow with a low pressure difference corresponding to the water head value between the sub tank 7 and the ink cartridge 4. It is set as follows.

[0058]

As described above, according to the present invention, ink is supplied from an ink tank to a sub-tank via a sub-tank, and waste ink from the ink-jet head is collected in a sub-tank through a filter to enable reusable ink. In an ink jet recording apparatus having a circulating system, an ink recovery unit is arranged in front of a filter so that waste ink collected in an ink recovery unit can be directly recovered in a waste ink tank without passing through a filter.

Therefore, in the present invention, when the waste ink collected in the ink collecting section is discharged to the outside by using a pump or the like, dust and the like accumulated in the waste ink passage portion on the front side of the filter are accordingly discharged. Foreign matter can be discharged to the outside together. In addition, since the ink in the sub-tank also flows back through the filter and is discharged to the outside via the ink recovery unit, foreign substances such as dust captured by the filter are also washed away.

Therefore, according to the present invention, the filter disposed in the ink recovery path is clogged in order to reuse the waste ink, and the internal pressure in the waste ink recovery path increases, causing ink leakage and the like. Evil effects can be prevented beforehand. Further, the frequency of replacing the filter can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram mainly showing an ink circulation system of an ink jet recording apparatus to which the present invention is applied.

FIG. 2 is an explanatory diagram showing an example of the detector of FIG.

FIG. 3 is a schematic flowchart showing an ink supply / discharge operation in the inkjet recording apparatus of FIG. 1;

FIG. 4 is an explanatory view showing another example of the sub tank of FIG. 1;

FIG. 5 is an explanatory diagram showing another configuration example of the sub-tank and the ink recovery unit in FIG. 1;

FIG. 6 is an explanatory diagram showing another example of the ink circulation system of FIG. 1;

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Inkjet head 3 Ink cartridge mounting section 4 Ink cartridge 5 Ink supply path 6 Ink supply pump 7, 7A, 7B Sub tank 8 Ink supply path 9 Head cap 10 Ink recovery pump 11 Ink recovery path 12 Ink recovery unit 13 Ink storage unit 13A Ink supply chamber 13B Air release chamber 14 Filter 15 Ink discharge path 16 Waste ink tank 17 Discharge pump 18 Vent 19 Solenoid valve 21, 22 Liquid level sensor 23, 23A, 23B Detector 41 Fine filter 42 Inclined ceiling

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masahiro Fujii 3-3-5 Yamato, Suwa City, Nagano Prefecture Seiko Epson Corporation F-term (reference) 2C056 EA27 EB16 EB21 EB29 EB32 EB38 EB50 JC04 JC14 KB04 KB09 KB11 KB16 KB26 KB27 KB37 KC01 KC16

Claims (13)

[Claims] 1. An ink tank, an ink jet head, a sub tank for supplying ink supplied from the ink tank to the ink jet head at a predetermined supply pressure, and removing dust and the like from waste ink discharged from the ink jet head. An ink-jet recording apparatus configured to return waste ink that has passed through the filter to the sub-tank, an ink recovery unit disposed in a waste ink passage that guides the waste ink to the filter, An ink jet recording apparatus having a waste ink tank for collecting the waste ink collected in the ink collecting section without passing through the filter. 2. The ink jet recording apparatus according to claim 1, further comprising a discharge pump for discharging the waste ink collected by the ink collection unit to the waste ink tank. 3. The detecting means according to claim 2, wherein said detecting means detects that the ink supplied from said ink tank to said sub-tank has exceeded a use limit, and said discharge pump is drive-controlled in accordance with a detection result of said detecting means. An ink jet recording apparatus comprising: 4. The ink tank according to claim 1, wherein the sub-tank includes an ink storage unit that stores the ink supplied from the ink tank, and the ink recovery unit. An ink-jet recording apparatus, wherein the ink-jet recording apparatus communicates via the filter. 5. The ink supply chamber according to claim 4, wherein the ink storage unit includes an ink supply chamber communicating with the ink tank and the inkjet head, and an air opening chamber having a vent. And the atmosphere opening chamber are communicated via a second filter finer than the filter, and the atmosphere opening chamber and the ink recovery unit are communicated via the filter. An ink jet recording apparatus comprising: 6. The ink supply chamber according to claim 5, wherein a ceiling surface of the ink supply chamber is inclined upward toward the atmosphere opening chamber, and an upper end of the ceiling surface is located between the ink supply chamber and the atmosphere opening chamber. An ink jet recording apparatus, wherein the second filter is arranged at a partition. 7. The ink jet recording apparatus according to claim 1, wherein the ink tank is a cartridge type ink tank. 8. The ink jet recording apparatus according to claim 7, wherein the cartridge type ink tank includes the waste ink tank. 9. The ink jet recording apparatus according to claim 7, wherein the detecting means detects whether or not the ink in the ink tank has exceeded a use limit based on an elapsed time after the replacement of the ink tank. . 10. The method according to claim 7, wherein the detecting means detects whether or not the ink in the ink tank has exceeded a use limit based on a waste ink recovery amount recovered in the waste ink tank after the ink tank replacement. An inkjet recording apparatus. 11. The ink jet recording apparatus according to claim 1, wherein the detecting means detects whether or not the ink in the ink tank has exceeded a use limit based on a change in ink characteristics. 12. The ink jet recording apparatus according to claim 11, wherein the change in ink characteristics is a change in ink density or ink viscosity. 13. The sub-tank according to claim 3, wherein a recovery pump for recovering waste ink discharged from the inkjet head to the ink recovery unit, a supply pump for supplying ink from the ink tank to the sub-tank, and the sub-tank And a liquid level sensor for detecting a liquid level in the ink jet recording apparatus.