JP2000062210A - Inkjet printer - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To enable stable continuous printing operation while ensuring smooth ink flow over a long period of time. SOLUTION: A hollow cylindrical body 81 is hermetically partitioned by one lid member 81D and the other lid member 81U, and one opening 85HD is liquid-sealed to one lid member and another opening 85HU is formed in the hollow cylindrical body. On the other hand, a hollow cylindrical filter 85 mounted in a state of being liquid-sealed on the lid member, an ink introduction portion 82 capable of introducing ink Qia into the filter from the upstream side of the ink supply pipe 24, and a filter radially inward. An ink lead-out portion 83 that can lead the ink Qi that has passed from the outside to the outside and accumulated in the hollow cylindrical body to the downstream side of the ink supply pipe;
The filter device 80 including the air discharge portion 84 capable of discharging the air Qa accumulated in the filter to the outside is arranged such that the ink introduction portion of the hollow cylindrical body 81 is on the lower side and the ink outlet portion and the air discharge portion are on the upper side. Arranged as side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter device capable of printing while supplying ink from an ink tank to a nozzle head having a plurality of ink jet nozzles through an ink supply tube and removing foreign matter by a filter device provided in the middle of the ink supply tube. Relates to a possible formed inkjet printer.

[0002]

2. Description of the Related Art A nozzle head for each color, in which an ink cassette is mounted, is reciprocated over the entire length (width) in the row direction, and printing is performed during each forward movement to print one line (or 1 / N line).
Compared with a conventional type (so-called serial type) inkjet printer that prints, prints one line (or 1 / N line), and then feeds the print medium (plain paper, OHP paper, etc.) one line in the column direction and repeats these. Therefore, the applicant of the present invention is an ink jet printer capable of achieving a significant increase in printing speed and capable of continuous printing operation over a large number of sheets, and also capable of achieving a significant reduction in size as compared with a known electrophotographic method (so-called laser printer). (For example, Japanese Patent Laid-Open No. 10-138520).

In such a proposed printer, in order to carry out continuous printing operation on a large number (for example, 500 or more) of print media, it cannot be increased due to the reciprocal movement in the row direction unlike the conventional serial type ink jet printer (that is, Just consuming the ink in the (small) ink cassette will run out of ink.

Therefore, an ink supply means 20 as shown in FIG. 3 is provided so that printing can be performed while supplying ink from the ink tank 22 to the nozzle head 10.

In FIG. 3 showing one color, ink is supplied from an ink tank 22 to a nozzle head 10 (ink chamber 11) having a plurality of ink jet nozzles 12 and ink is sprayed from each selected ink jet nozzle 12. Color printing can be performed on a medium (for example, A4 paper) at a high speed of 20 PPM.

Here, the ink supply means 20 comprises an ink tank 22, an ink supply pipe 24, an ink supply pump 25, etc., and the ink tank 22 is connected to the nozzle head 10.
Ink is supplied to the (ink chamber 11). In addition, the ink tank 22 is replenished with ink from an ink bottle 21 that can be attached to and detached from the ink tank 22, and the ink liquid level can be adjusted to be constant.
23 is an air intake.

The ink returning means 30 related thereto includes an ink returning tube 31 and an ink returning valve 32, and can return the ink from the ink chamber 11 to the ink tank 22. That is, it is used independently when the ink is circulated in cooperation with the ink supply unit 20 or when the ink is removed from the ink chamber 11.

The ink supply means 20 and the ink return means 30 are formed as an integral structure, that is, an ink supply processing module 1, in which four colors are detachably attached to the ink jet printer. This is much more effective for simplifying the structure on the printer side. That is, when the module 1 is attached to the printer, one ends of the ink supply pipe 24 and the ink return pipe 31 are formed so as to be able to communicate with the ink chamber 11 via an automatic opening / closing cap structure (not shown).

The ink supply pipe 24 and the ink return pipe 31 are formed of highly elastic tubes, and the ink supply pump (valve) 25 and the ink return pump (valve) 32 are connected to the respective pipes (24, 31). ) Is formed from a tube pump having a valve function that can be selected from an open state and a closed state.

When the ink supply pump 25 is activated to supply ink to the nozzle head 10 while heating, for example, and the ink return pump 32 is activated to return ink from the nozzle head 10 to the ink tank 22, an ink circulation operation is performed. Ink warming up is possible. If the ink return pump 32 is stopped and the ink supply pump 25 is activated to supply ink continuously or intermittently, printing operation and maintenance of the nozzle head 10 (air bleeding, etc.) can be performed.

Further, the impact purge mechanism 2 is formed in the middle of the ink supply pipe 24 of the ink supply means 20 and includes a front valve 28 and a rear valve 29 so that the nozzle head 10 (ink jet nozzle 12) can be cleaned.
7 is provided.

Further, the ink discharging means 40 receives the ink ejected from the ink jet nozzle 12 from the ink receiver 4
A means for receiving the waste ink at 1, and temporarily holding it in a receiving tank 42 having a gas-liquid separating function, which is communicated with the waste ink bottle 50 through a communication pipe 43 and discharging the waste ink to the waste ink bottle 50 side through a pump 45 and a total discharge pipe 49 Is.

The waste ink overflowing from the ink tank 22 is temporarily held in the overflow tank 62 through the overflow pipe 61 forming the overflow discharge means 60 and is the same as the waste ink in the ink receiving tank 42. It is discharged to 50.

The ink discharging means 40 and the overflow discharging means 60 are also integrally configured as the waste ink discharging processing module 2 similar to the case of the module 1, and can be attached to and detached from the printer. Further, the waste ink bottle 50 can be attached and detached in the directions of arrows A and B.

Here, in order to perform smooth printing operation and high quality printing, it is extremely important to reliably remove dust and air mixed in the ink supplied to the nozzle head 10.

Therefore, a filter device 80P for cleaning the ink is provided in the middle of the ink supply pipe 24. As shown in FIG. 4, the filter device 80P includes a filter 80F1 that partitions the cross section of the ink supply pipe 24.

[0017]

However, when it becomes necessary to further delicate the ink jet nozzle 12, that is, to further improve the printing resolution, it becomes necessary to remove extremely small dust and the like, and the filter 80F1 Faster clogging. This not only hinders the continuous printing operation of a large number of sheets, but also makes the replacement work of the filter 80F1 troublesome. In addition, stains on the surrounding ink are likely to occur in proportion to the number of times of replacement work. Further, the meaning of facilitating the replacement of the ink supply means 20 and the like as the module 1 is diminished.

To extend the replacement period, as shown in FIG.
The filter 80F2 having the expanded diameter portion 24F and having a large effective filter area may be employed, but it is difficult to extend the filter replacement period sufficient to meet the near future requirements (removal of finer dust). Is. Moreover, the expanded portion 2
If 4F is increased in the radial direction, the fluidity of the ink will drop due to the relationship with the ink supply capacity of the ink supply means 20, and only the filter device 80P will be significantly larger than the other components. That is, it becomes a cause of hindering the miniaturization of the printer.

Further, depending on the structure of the ink supply means 20 and the use environment (temperature, etc.), the filters 80F1, 80F2
The amount of air accumulated on the upstream side of the ink flow direction may increase. In the worst case, the ink flow may stop even though the filter is not clogged.

Thus, in order to ensure the stable printing operation of a large number of continuous sheets at high speed, it is important to eliminate such problems.

An object of the present invention is to provide an ink jet printer provided with a small filter device having a simple structure capable of greatly expanding a filter action effective area and capable of performing stable continuous printing operation while ensuring smooth flow of ink for a long period of time. Especially.

[0022]

According to a first aspect of the present invention, printing is possible while ink is supplied from an ink tank to a nozzle head having a plurality of ink jet nozzles through an ink supply tube, and the ink is inserted in the middle of the ink supply tube. In an inkjet printer formed so that foreign matters can be removed by a filter device, the filter device includes a hollow cylindrical body that is hermetically partitioned by one lid member and the other lid member, and one opening has one lid in the hollow cylindrical body. A hollow cylindrical filter which is liquid-sealed to the member and has the other opening liquid-sealed to the other lid member, and ink is inserted into the filter through the one lid member from the upstream side of the ink supply pipe. Ink that is formed so that it can be introduced and ink that has passed through the filter from the inside to the outside in the radial direction and that has accumulated in the hollow cylinder is located downstream of the ink supply pipe. A hollow cylinder, which is composed of an ink outlet portion formed so as to be able to be discharged through the other lid member and an air discharge portion formed so as to be able to discharge the air accumulated in the filter through the other lid member. An ink jet printer in which the body is disposed with the ink introduction portion on the lower side and the ink outlet portion and the air discharge portion are disposed on the upper side.

In the invention, the ink supplied from the upstream side of the ink supply pipe is in a state in which one opening is liquid-sealed by the one lid member and the other opening is liquid-sealed by the other lid member in the hollow cylinder. The ink is introduced into the installed hollow cylindrical filter through the ink introducing portion provided on the side of the one lid member, passes through the filter from the inner side to the outer side, and accumulates in the hollow cylindrical body. The ink that has passed through the filter is led out to the downstream side of the ink supply pipe through the ink lead-out portion that passes through the other lid member. Since the filter can be lengthened in the ink flow direction, the effective filter action area can be greatly expanded as compared with the conventional example orthogonal to the ink flow direction.

Further, the air dissolved or mixed in the ink is pushed into the other lid member inside the hollow cylinder without passing through the filter in the radial direction, and is passed through the air outlet portion provided in the other lid member to the outside (for example, , Discharge pipe). Therefore, it is possible to reliably prevent the air from covering the filter surface, that is, the surface clogging of the filter.

Therefore, since the effective area of the filter action can be greatly expanded while the discharge of air is promoted and the structure can be simplified and downsized, stable continuous printing operation can be performed while ensuring smooth ink flow for a long period of time, and the filter By extending the replacement period, it is possible to reduce personnel, downsize the entire printer, and reduce costs.

Further, the invention of claim 2 is an ink jet printer in which the hollow cylindrical body and the filter are formed in a cylindrical shape.

In this invention, since the hollow cylinder and the filter have a cylindrical shape, the same operational effect as in the case of the invention of claim 1 can be obtained, and further, the maximum filter operation can be achieved with the minimum volume. The effective area can be established.

Further, according to a third aspect of the present invention, the opening / closing state of the ink opening / closing valve provided on the downstream side of the ink supply pipe and the air opening / closing valve connected to the air discharge portion can be switched in reverse. It is an inkjet printer.

In this invention, during the printing operation, the ink on-off valve provided on the downstream side of the ink supply pipe is opened and the air on-off valve connected to the air discharge section is closed. Then, for example, the valve switching is performed at a certain time during the printing operation to close the ink opening / closing valve provided on the downstream side of the ink supply pipe and open the air opening / closing valve connected to the air discharge portion.

Thus, the air accumulated in the hollow cylindrical filter can be forcibly led out to the outside (for example, the exhaust pipe) through the air lead-out portion penetrating the other lid member. During the air discharge, ink can be supplied to the nozzle head by utilizing the negative pressure generated by the nozzle head. After discharging the air, the valve switching may be reversed. The time from the preceding valve switching to the subsequent valve reverse switching may be a short time (for example, 5 seconds) that does not hinder continuous printing operation.

Therefore, in addition to the same operational effects as in the case of each of the first and second aspects of the present invention, the air can be discharged automatically, so that the handling is simple and the continuous printing operation time is further improved. Can be extended.

Further, according to the invention of claim 4, when the ink on-off valve is switched to the closed state and the air on-off valve is switched to the open state, the ink supply pump provided on the upstream side of the ink supply pipe can be driven. Is an inkjet printer formed on the.

In this invention, the ink supply pump is driven to positively supply the ink into the filter during the air discharging operation in which the ink on-off valve is closed and the air on-off valve is switched to the open state. Therefore, in addition to the same operational effect as in the case of the invention of claim 3, the air venting time can be further shortened.

Further, the invention of claim 5 is an ink jet printer in which the other opening of the air opening / closing valve is connected to an ink recovery tank through a discharge pipe.

In this invention, the ink contained in the air drawn out from the air opening / closing valve is collected in the ink collecting tank through the discharge pipe. Therefore, in addition to the same operational effects as in the case of each of the third and fourth aspects of the invention, the surroundings are not contaminated by the ink contained in the exhaust air.

[0036]

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

(First Embodiment) As shown in FIG. 1, the present ink jet printer has a hollow cylinder 81 which is hermetically partitioned by one lid member 81D and another lid member 81U, and inside this hollow cylinder 81. A filter 85 having a hollow cylindrical shape in which one opening 85HD and the other opening 85HU are mounted in a liquid-sealed state, and ink introduction for introducing the ink Qia into the filter 85 from the upstream side 24A of the ink supply pipe 24. Ink Qi that has passed through the portion 82 and the filter 85 from the inner side to the outer side in the radial direction and has accumulated in the hollow cylindrical body 81.
A filter device 80 including an ink lead-out portion 83 for leading the ink to the downstream side 24B of the ink supply pipe 24 and an air discharge portion 84 for discharging the air Qa accumulated in the filter 85 through the discharge pipes (71 ... 61). The filter device 80 is provided such that the ink introduction part 82 of the hollow cylindrical body 81 is on the lower side and the ink discharge part 83 and the air discharge part 84 are on the upper side, and the filter action effective area is promoted while promoting the discharge of air. Is greatly expanded, and stable continuous printing operation can be performed while ensuring smooth ink flow for a long period of time.

As in the case of the conventional example (FIG. 3), the ink jet printer is capable of printing while supplying ink from the ink tank 22 to the nozzle head 10 having a plurality of ink jet nozzles 12 through the ink supply pipe 24. A foreign matter can be removed by a filter device 80 provided in the middle of the supply pipe 24. Therefore, the same parts as those of the conventional example (FIG. 3) are designated by the same reference numerals, and the description thereof will be simplified or omitted.

However, in the first embodiment, the air venting means 70 indicated by the two-dot chain line in FIG. 3 is provided for the sake of convenience. The means 70 is for smoothly and promptly maintaining the filter device 80.

That is, the air venting means 70 includes an air venting pipe 71 and an air venting valve 72, and the filter device 8
The ink contained in the air Qa discharged when the air Qa is discharged from 0 is formed in the ink recovery tank (overflow tank 62) in the same manner as in the case of the ink overflowing from the ink tank 22. This is to prevent ink stains on the surroundings.

As shown in FIG. 1, the hollow cylindrical body 81 constituting the filter device 80 is hermetically partitioned by the one lid member 81D and the other lid member 81U, and is formed so as not to leak ink. There is. The one lid member 81D and the other lid member 81U are removable. This is because only the filter 85 described later in detail can be replaced. However,
The filter 85 may be a disposable structure because it is difficult to remove.

The diameter of the hollow cylinder 81 is larger than the diameter of the ink supply pipe 24, but can be made much smaller than the diameter in the conventional example (FIG. 5) due to the radial expansion. That is, the size and weight can be reduced. However, the shape of the hollow cylindrical body 81 can be implemented even if it is a polygonal cylindrical body or the like.

The hollow cylinder 81, together with the filter 85, has a hollow cylinder shape (in this embodiment, a cylindrical shape).
The filter action effective area is expanded while the volume is reduced. This is because the rigidity of the filter 85 can be increased and the cost can be reduced by facilitating the processing.

Further, the ink supply pipe 2 is provided in the hollow cylindrical body 81.
4, the ink introducing portion 82 that can penetrate the one-side lid member 81D from the upstream side 24A and introduce the ink Qia into the filter 85 (Sia), and the hollow cylinder 81 that passes through the filter 85 from the inside to the outside in the radial direction. The ink Qi accumulated in (Si) is applied to the downstream side 24B of the ink supply pipe 24 by the other lid member 8
The ink lead-out portion 83 that can be led out through 1U and the air Qa accumulated in the filter 85 (Sa) are used for the other lid member 81.
An air discharge portion 84 capable of discharging through U is provided.

In FIG. 1, Sia is an air-containing ink flow chamber, Si is an ink flow chamber, Sa is an air reservoir chamber, Qia is an air-containing ink, Qi is an ink containing no air, and Qa is air.

This hollow-cylindrical filter 85 is made of a porous sheet material having sponge-like micropores, and one opening 85HD is covered in the hollow cylindrical body 81 via one O-ring (sealing member) 88D. The liquid is sealed to the inner surface of the member 81D and the other O-ring (sealing member) 8
The other opening 85HU is attached to the inner surface of the other lid member 81U via 8U in a liquid-sealed state.

Therefore, the upstream side 2 of the ink supply pipe 24
4A, that is, the air-containing ink Qia supplied from the lower side of the hollow cylindrical body 81 penetrates the ink introducing portion 82 and is introduced into the ink flow chamber Sia inside the hollow cylindrical body 81 and inside the cylindrical filter 85, and Small dust and the like are removed while passing through the filter 85 from the inside to the outside in the radial direction.

The ink Qi that has passed through the filter 85 collects in the ink flow chamber Si in the hollow cylinder 81, and more specifically, while flowing, passes through the ink outlet 83 and is located on the downstream side 24B of the ink supply pipe 24, that is, above the hollow cylinder 81. Be led to the side. Since the filter 85 is long in the ink flow direction,
Compared with the case of the conventional example (FIG. 5) that is orthogonal to the ink flow direction, the filter action effective area can be greatly expanded.

The air Qa dissolved or mixed in the ink Qia is pushed into the air reservoir chamber Sa in the hollow cylindrical body 81 without passing through the filter 85 in the radial direction. After that, the ink lead-out portion 8 on the upper side of the hollow cylindrical body 81.
4 is led to an external exhaust pipe (on the side of the air vent pipe 71). Therefore, it is possible to reliably prevent the air Qa from covering the filter surface.

That is, if the filter device 80 is provided, the effective area of the filter action can be greatly expanded while the discharge of the air Qa is promoted, and the structure can be simplified and downsized, so that the smooth ink flow can be secured for a long period of time. It is understood that stable continuous printing operation can be performed, and the replacement period can be extended to reduce personnel, downsize the entire printer, and reduce costs.

Further, in actual operation, the switching control means 100 is provided, and the ink opening / closing valve (pre-position valve 28) provided on the downstream side 24B of the ink supply pipe 24 and the air discharging portion 84 (air discharging). The open / close state of the air on / off valve (air bleeding valve 72) connected to the pipe 71) can be switched in reverse.

That is, the switching control means 100 keeps the ink on-off valve (28) provided on the downstream side 24B of the ink supply pipe 24 open and discharges air during the printing operation, for example, when there is no maintenance command. The air opening / closing valve (72) connected to the portion 84 (71) is closed.

Then, for example, when a maintenance command is issued at a certain time during the printing operation, valve switching is executed. That is, the ink on-off valve (28) provided on the downstream side 24B of the ink supply pipe 24 is closed and the air discharge portion 84 (7).
The air on-off valve (72) connected to 1) is opened.

As a result, the cylindrical filter 85 (S
The air Qa accumulated in a) can be led out to the outside (62) side through the ink lead-out portion 84 penetrating the other lid member 81U. It should be noted that the ink Qi can be supplied to the nozzle head 10 during the air discharge by utilizing the negative pressure generated by the nozzle head 10.

After this air discharge, the valve switching may be reversed. Since the time from the previous valve switching to the subsequent valve reverse switching may be a short time (for example, 5 seconds) that does not hinder the continuous printing operation, the continuous printing operation can be further extended. Further, since the air can be automatically discharged, it is easy to handle.

Further, the drive control means 100 causes the upstream side 2 of the ink supply pipe 24 when the ink opening / closing valve (28) is closed and the air opening / closing valve (72) is opened.
The ink supply pump 25 provided in 4A is driven to positively supply the ink Qia into the filter 85 (Sia). That is, the repulsive action of the air Qa is promoted. Therefore, the air venting time can be further shortened.

(Second Embodiment) This embodiment is shown in FIG.
As shown in FIG. 7, the basic configuration is similar to that of the first embodiment (FIG. 1), but a cup-shaped ring member 89 having a hole 89H communicating with the ink outlet 24 is further provided in the hollow cylindrical body 81. It is arranged in the upper part, and the volume of the air reservoir chamber Sa is enlarged.

Therefore, not only can the same effect as in the case of the first embodiment can be obtained, but even if the air is apt to be mixed into the ink immediately after the replacement of the ink bottle 21, the contained air is mixed with the ink Qi. Therefore, it does not enter the downstream side 24B of the ink supply pipe 24.

[0059]

According to the first aspect of the present invention, the filter device includes a closed hollow cylindrical body, a hollow cylindrical filter, an ink introducing portion for introducing ink into the filter, and the filter in the radial direction. The filter device is composed of an ink outlet portion for discharging the ink that has passed from the inside to the outside and accumulated in the hollow cylinder to the downstream side of the ink supply pipe, and an air outlet portion for discharging the air accumulated in the filter. Since the ink jet printer has the hollow cylinder body with the ink introduction part on the lower side and the ink discharge part and the air discharge part on the upper side, it is possible to greatly expand the effective area of the filter action while promoting the discharge of air. Since it is simple and compact, stable continuous printing operation can be performed while ensuring smooth ink flow for a long period of time, and the number of personnel can be reduced by extending the filter replacement period. Downsizing and cost reduction of the entire motor.

Further, according to the invention of claim 2, since the hollow cylindrical body and the filter are formed in a cylindrical shape, the same effect as in the case of the invention of claim 1 can be obtained, and further, The maximum effective filtration area can be established with the minimum volume.

According to the third aspect of the invention, the open / close state of the ink opening / closing valve provided on the downstream side of the ink supply pipe and the air opening / closing valve connected to the air discharge portion can be switched in reverse. Therefore, in addition to being able to achieve the same effects as those of the inventions of claim 1 and claim 2,
Furthermore, since the air can be automatically discharged, it is easy to handle and the continuous printing operation time can be further extended.

Further, according to the invention of claim 4, when the ink on-off valve is closed and the air on-off valve is switched to the open state, the ink supply pump is driven to forcibly supply ink. In addition to the same effect as the case of the invention of claim 3, the air bleeding time can be further shortened.

Further, according to the invention of claim 5, since the other port of the air on-off valve is connected to the ink recovery tank via the discharge pipe, the same as in the case of each of the inventions of claims 3 and 4. In addition to the effect, it is possible to prevent the surroundings from being contaminated with the ink contained in the exhaust air.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a second embodiment of the present invention.

FIG. 3 is an overall system diagram for explaining the previously proposed inkjet printer.

FIG. 4 is a diagram for explaining a conventional filter device (1).

FIG. 5 is a diagram for explaining a conventional filter device (2).

[Explanation of symbols]

1 Ink supply processing module 2 Waste ink discharge processing module 10 nozzle head 11 ink chamber 12 inkjet nozzles 20 Ink supply means 21 ink bottles 22 Ink tank 24 Ink supply pipe 24A upstream of ink supply pipe 24B Downstream of ink supply pipe 25 ink supply pump 26 filters 27 Impact purge mechanism 28 Front valve 28 (ink on-off valve) 30 Ink return means 40 Ink discharging means 50 waste ink bottles 60 Overflow discharge means 61 Overflow pipe (exhaust pipe) 62 Overflow tank (ink collection tank) 70 Air venting means 71 Air vent pipe (exhaust pipe) 72 Air vent valve (air on-off valve) 80 filter device 81 hollow cylinder 81D One-side lid member 81U Other lid member 82 Ink introduction section 83 Ink outlet 83V ink on-off valve 84 Air exhaust unit 84V air on-off valve 85 Filter 85HD One side opening 85HU other opening 88D, 88U O-ring 100 switching control means

Continued front page    (72) Inventor Yasuhiro Suzuki             6-78 Minamimachi, Mishima City, Shizuoka Prefecture             Ku Mishima Office (72) Inventor Hitoshi Shioki             6-78 Minamimachi, Mishima City, Shizuoka Prefecture             Ku Mishima Office F-term (reference) 2C056 EA26 JC13 KA01 KB04 KB08                       KB10 KB11 KB26 KB29

Claims (5)

[Claims] 1. An ink jet formed to be able to print while supplying ink from an ink tank to a nozzle head having a plurality of ink jet nozzles through an ink supply pipe and to remove foreign matters by a filter device interposed in the middle of the ink supply pipe. In the printer, the filter device includes a hollow cylindrical body which is hermetically partitioned by one lid member and the other lid member, and one opening is liquid-sealed in the one lid member and the other opening is the other in the hollow cylindrical body. A hollow-cylindrical filter mounted in a liquid-sealed state on the lid member, and an ink introducing portion formed so that ink can be introduced into the filter from the upstream side of the ink supply pipe by penetrating the one lid member, Ink that has passed through the filter from the inside to the outside in the radial direction and that has accumulated in the hollow cylinder can be led out through the other lid member to the downstream side of the ink supply pipe. The ink outlet part is formed and the air discharge part is formed so that the air accumulated in the filter can be discharged through the other cover member, and the hollow cylinder is made to have the ink introduction part on the lower side. An ink jet printer in which a lead-out section and an air discharge section are arranged on the upper side. 2. The ink jet printer according to claim 1, wherein the hollow cylinder and the filter are formed in a cylindrical shape. 3. The ink opening / closing valve provided on the downstream side of the ink supply pipe and the air opening / closing valve connected to the air discharge part are formed so as to be capable of switching the open / closed states in reverse. The inkjet printer according to claim 2. 4. The ink supply pump provided on the upstream side of the ink supply pipe is drivable when the ink on-off valve is closed and the air on-off valve is opened. 3. The inkjet printer described in 3. 5. The ink jet printer according to claim 3, wherein the other opening of the air opening / closing valve is connected to an ink recovery tank via a discharge pipe.