JP2003053995A - Ink jet printer and ink tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance reliability of ink supply operation by protecting a ventilation film against damage. SOLUTION: The ink jet printer comprises a recording head 4 for recording on a sheet 3 by ejecting ink, and a main tank 5 for containing ink being supplied to the recording head 4. The ink jet printer also comprises a subtank 6 comprising a section 16 for containing ink supplied from the main tank 5, an opening 23 for sucking air in the ink containing section 16, and a ventilation film 24 provided to close the suction opening 23 and having characteristics for passing only gas. The ink jet printer further comprises a joint section 8 for supplying ink from the main tank 5 to the subtank 6, a cap 35 for sucking air in the ink containing section 16 of the subtank 6 through the suction opening 23, and a cut 25 for suppressing a stress being generated when the ventilation film 24 is pressed against the fringe of the suction opening 23 with a negative pressure generated by the cap 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer for recording information such as characters and images by ejecting ink onto a recording medium such as paper or film. Also,
The present invention relates to an ink tank that stores ink to be supplied to a recording head that records information such as characters and images by ejecting ink onto a recording medium such as paper or film.

[0002]

2. Description of the Related Art Conventionally, there is known an ink jet printer which records information such as characters and images by ejecting ink onto a recording medium such as paper or film. This type of inkjet printer includes an ink supply unit that supplies ink to a recording head that ejects ink.

In the ink supply means, a head cartridge in which a recording head is integrally provided in an ink tank containing ink is mounted on a carriage which is moved in the scanning direction of a recording medium such as paper. Method (hereinafter,
This is called the on-carriage method. ) Is used. As the on-carriage system, a configuration in which the recording head and the ink tank are separately provided and the ink tank is mounted on the carriage provided with the recording head is also applied.

Further, in the ink supply means, the recording head is provided on the carriage, and the ink tank is fixed to a position other than the carriage, for example, a chassis in the apparatus, and led out from the ink tank via the supply tube. A method (hereinafter referred to as a tube method) configured to supply the ink to the recording head on the carriage is used.

By the way, in the above-described on-carriage system, since the ink tank is provided on the carriage, the weight of the entire carriage becomes large, so that it becomes difficult to move the carriage at a high speed for scanning. In addition, this on-carriage system, in order to reduce the weight of the entire carriage, when the ink tank is downsized,
There is an inconvenience that the amount of ink stored in the ink tank becomes small and the number of sheets that can be continuously recorded on the paper becomes small.

Further, the above-mentioned tube system has a disadvantage that it is difficult to miniaturize the ink jet printer because the carriage and the ink tank are connected through the supply tube.

Therefore, in consideration of the inconveniences of the on-carriage system and the tube system described above, a print head and a sub tank for accommodating a relatively small amount of ink to be supplied to the print head are respectively provided on the carriage and supplied to the sub tank. There has been proposed a method (hereinafter referred to as a pit-in method) in which a main tank that stores the ink is provided in the apparatus.

In the pit-in system, when the ink in the sub-tank of the carriage is reduced to a predetermined amount or less, the carriage is moved to a predetermined position (home position or supply position) to supply the ink to the sub-tank, and the predetermined position is set. Ink is supplied from the main tank to the sub tank by connecting the main tank and the sub tank at the position.

According to this pit-in system, the amount of ink mounted on the carriage is reduced as compared with the on-carriage system, so that the weight of the carriage is reduced and the carriage can be transported at high speed. With
Since the ink is supplied to the sub tank at a predetermined position, the number of sheets that can be continuously recorded on the paper can be increased. Further, according to this pit-in system, unlike the tube system, it is not necessary to connect the carriage and the main tank via the supply tube, so that the configuration can be greatly simplified.

And as an example of the pit-in system,
When the sub-tank is provided with a gas permeable film that has the property of allowing only gas to permeate and not allowing liquid ink to permeate, and when this gas permeable film is used as a gas-liquid separating member and ink is sufficiently supplied into the sub tank There is a configuration used as a control valve for stopping the ink supply.

The conventional ink jet printer to which the pit-in system utilizing the above-mentioned breathing film is applied is roughly as follows.
A main tank that stores ink to be supplied to the recording head and a carriage that supports the recording head and that has a sub tank to which the ink is supplied from the main tank and that is transported in the main scanning direction are provided. Further, this conventional inkjet printer is provided with a joint portion for supplying ink from the main tank to the sub tank, and a suction portion for sucking air in the sub tank through the ventilation film.

The main tank is removably provided in the apparatus and has an ink containing portion for containing ink to be supplied to the sub tank of the carriage. Further, a supply connection portion to which the joint portion is connected is provided on the outer portion of the main tank.

A sub-tank is integrally provided on the carriage. The sub-tank has each ink storage portion that stores each ink of four colors. As shown in FIG. 7, a connection port 121 to which a suction unit for generating a negative pressure for supplying ink from the main tank is connected, and a suction port for sucking air in the ink storage unit. The partition wall 122 provided with the mouth 123 and the suction port 12
And a ventilation film 124 for controlling the ink supplied from the main tank.

The gas permeable membrane 124 is formed by stretching a porous material such as polytetrafluoroethylene (PTFE) and intertwining fibers, and is joined to the opening edge of the suction port 123 over the outer peripheral portion. There is. This breathable membrane 124
Has a property of allowing air to pass therethrough, but when the liquid comes into contact with the liquid, the liquid does not pass under a predetermined pressure (pressure resistance) due to the surface tension of the liquid. Therefore, this ventilation film 124 is
When the ink supplied to the ink containing portion reaches the gas permeable film 124 and the ink is filled in the ink containing portion, it functions as a control valve for stopping the supply of the ink, that is, a so-called full valve, and enters the ink containing portion. Stop the ink supply.

The partition portion 122 is formed in the ink containing portion so as to cover the connection port 121 in an airtight state, and the suction port 123 is provided at a position facing the connection port 121. The outer peripheral portion of the ventilation film 124 is joined along the opening edge of the suction port 123.

Four joint parts are provided corresponding to each ink storage part of the sub tank 106, and a supply connection part connected to the ink supply port of the sub tank 106 is provided.

The suction portion is the connection port 12 of the sub tank 106.
1 and a pump 137 for sucking the air in the ink containing portion via the connecting portion 136.

In the conventional ink jet printer configured as described above, when a predetermined amount of ink in the sub-tank 106 is used, the supply connection part of the joint part is connected to the ink supply port of the sub-tank 106, and the main tank is connected. Be communicated to. At this time, in the sub-tank 106, the connection member 136 of the suction unit is connected to the connection port 121, and the ink storage unit communicates with the pump 137. In this state, the ink jet printer drives the pump 137 to suck the air in the sub tank 106, so that the ink in the main tank is supplied into the sub tank 106 through the joint portion and the ink supply port. Then, in the inkjet printer, when the liquid surface of the ink supplied into the sub tank 106 reaches the surface of the ventilation film 124, the ventilation film 124 functions as a control valve, and thus the supply of ink is stopped.

[0019]

By the way, the conventional ink jet printer to which the pit-in system utilizing the gas permeable membrane 124 is applied as described above, when ink is supplied to the sub tank 106, as shown in FIG. The gas permeable membrane 124 is elastically displaced into the suction port 123 as shown by the broken line in FIG. 7 in association with the suction by the pump 137, and is returned to the initial state by stopping the suction by the pump 137.

In this conventional ink jet printer, the ink reaches the surface of the aeration film 124 in a so-called full state in which the sub tank 106 is sufficiently supplied with ink and the sub tank 106 is filled with ink. ,
The surface of the ventilation film 124 is covered with ink. In this conventional inkjet printer, when suction is continued with the surface of the gas permeable membrane 124 covered with ink, the negative pressure due to the suction sharply rises, and the gas permeable membrane 124 reaches the opening edge of the suction port 123. It is pressed with a relatively large pressing force.

Therefore, the conventional ink jet printer has a problem that the ventilation film is broken and damaged by the opening edge of the suction port 123 as the above ink supply operation is repeated. Therefore, in the conventional ink jet printer, it becomes impossible to satisfactorily supply the ink from the main tank to the sub tank due to the breakage of the ventilation film.

Therefore, it is an object of the present invention to provide an ink jet printer and an ink tank capable of preventing the breathable film from being damaged and improving the reliability of the ink supply operation by the breathable film.

[0023]

In order to achieve the above-mentioned object, an ink jet printer according to the present invention includes a recording head for ejecting and recording ink on a recording medium, and a main body for accommodating the ink to be supplied to the recording head. And a tank. Further, this ink jet printer is provided with an ink containing portion for containing the ink supplied from the main tank, a suction port for sucking air in the ink storing part, and a gas provided so as to close the suction port. And a sub-tank having a gas permeable membrane having a property of transmitting only the gas. In addition, this ink jet printer has an ink supply unit that supplies ink from the main tank to the sub tank, a suction unit that sucks air in the ink storage portion of the sub tank through the suction port, and a gas permeable film is formed by negative pressure generated by the suction unit. And a stress suppressing means for suppressing the stress generated by being pressed against the opening edge of the suction port.

Further, the ink tank according to the present invention is attached to an ink jet printer having a main tank for containing ink to be supplied to the recording head. This ink tank includes an ink containing portion for containing ink supplied from a main tank on the ink jet printer side, a suction port for sucking air in the ink containing portion by suction means on the ink jet printer side, and this suction port. The air-permeable membrane is provided so as to be closed and has a characteristic of allowing only gas to permeate, and the stress-suppressing means for suppressing the stress of the air-permeable membrane being pressed against the opening edge of the suction port by the negative pressure of the suction means.

In the ink jet printer and the ink tank according to the present invention configured as described above, the ink is supplied from the main tank to the sub tank or the ink containing portion through the ink supply means. Further, according to the ink jet printer and the ink tank of the present invention, the stress suppressing unit suppresses the stress generated by pressing the gas permeable membrane against the opening edge of the suction port, so that the gas permeable membrane is damaged by the opening edge of the suction port. Is prevented from being damaged.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings of a serial type ink jet printer.

The ink jet printer of this embodiment is
Among the inkjet recording methods, in particular, a recording head equipped with a means for generating thermal energy as energy used for ejecting liquid ink and adopting a method of causing a change in ink state by the thermal energy is mounted. It is a printer. Especially in this embodiment,
A heating resistance element is used as a means for generating heat energy, and the ink is ejected by using the pressure of bubbles generated when the ink is heated by the heating resistance element to cause film boiling. The method is not limited to the method using a heating resistance element, and a method in which a mechanical vibration is applied to ink by using an electromechanical conversion element such as a piezo element, and ink is ejected by using the pressure due to this vibration May be adopted.

In the ink jet printer according to the present invention, paper is used as a recording medium on which information such as characters and images is recorded for the sake of convenience. For example, other sheet material such as film or three-dimensional curved surface is used. Of course, it may be adapted to be recorded.

(First Embodiment) As shown in FIGS. 1 and 2, an ink jet printer includes a recording head 4 for recording information on a sheet 3 and a main tank 5 for accommodating ink to be supplied to the recording head 4. A carriage 7 integrally provided with a sub-tank 6 that is integrally formed with the recording head 4 and that is supplied with ink from a main tank 5, and a joint portion 8 that supplies ink from the main tank 5 to the sub-tank 6.
And a recovery unit 9 that appropriately recovers the ink ejection state of the recording head 4 and sucks air from the sub tank 6 to supply the ink to the sub tank 6 through the joint unit 8.

Further, this ink jet printer has a transfer mechanism 11 for transferring the carriage 7 in the main scanning direction.
And a transport mechanism 12 for transporting the paper 3 in the sub-scanning direction.
It has and.

The recording head 4 is arranged at a position facing the conveyance path of the paper 3 of the carriage 7, and an ejection port (not shown) for ejecting ink is provided at a position opposed to the conveyance path of the paper 3. Has been. The recording head 4 has an electric resistance element (not shown) that generates thermal energy for ejecting the supplied ink. The recording head 4 ejects ink by, for example, film boiling by using thermal energy applied by an electric resistance element.

Although not shown, the main tank 5 is detachably attached to a tank mounting portion arranged at a position corresponding to a tank loading port provided in the apparatus. The main tank 5 is made of, for example, a resin material, and each ink containing portion 15 for containing each ink of four colors of yellow, cyan, magenta, and black for supplying to the sub tank 6 of the carriage 7 is a partition wall. Are provided separately.

The outer portion of the main tank 5 is provided with a supply connection portion (not shown) to which one end of the supply tube of the joint portion 8 is connected. Further, the main tank 5 is provided with a vent hole for making the atmospheric pressure in the ink containing portion 15 substantially equal to the external atmospheric pressure.

A recording head 4 is provided on the carriage 7 at a position facing the conveyance path of the paper 3. The carriage 7 has a sub-tank 6 that is configured integrally with the recording head 3 and that stores ink supplied from the main tank 5.
Are integrally formed. Here, in the sub tank 6,
It has an ink supply path for supplying ink from the sub tank 6 to the recording head 4, and the sub tank 6 and the recording head 4 are communicated with each other via this ink supply path.

The sub-tank 6 is provided with the ink storage portions 16 for storing the four color inks, respectively, separated by the partition walls. Ink absorbers 18a, 18 for absorbing and holding the ink supplied from the joint portion 8 are provided in each ink containing portion 16 corresponding to each color ink.
b are provided respectively. These ink absorbers 18
The a and 18b are formed of, for example, a porous body or a fibrous body having a liquid absorbing property, and are stacked and disposed in the ink containing portion 16. The ink absorbers 18a and 18b prevent the ink from leaking from the recording head 4 by applying a predetermined negative pressure to the ink in the nozzles of the recording head 4, respectively.

Further, each ink containing portion 16 of the sub tank 6
Each of the ink storage portions 16 is provided with a vent hole 19 for venting so as to make the atmospheric pressure inside the ink storage portion 16 substantially equal to the external atmospheric pressure. In addition, the main tank 5 is provided in each ink containing portion 16.
A connection port 21 is provided to which a recovery unit 9 described later that generates a negative pressure for supplying ink from is connected.

Further, in each ink containing portion 16, a partition wall portion 22 provided with a suction port 23 for sucking the air in the ink containing portion 16 and a main portion provided so as to close the suction port 23 are provided. A ventilation film 24 for controlling the ink supplied from the tank 5 is provided.

The gas permeable membrane 24 is formed as a thin film by stretching a porous material such as polytetrafluoroethylene (PTFE) and intertwining the fibers, and extends over the outer peripheral portion at the opening edge of the suction port 23. It is joined. This breathable membrane 24
Has a property of allowing air to pass therethrough, but when the liquid comes into contact with the liquid, the liquid does not pass under a predetermined pressure (pressure resistance) due to the surface tension of the liquid. Therefore, the ventilation film 24 is a control valve that stops the supply of ink when the ink supplied to the ink storage portion 16 reaches the ventilation film 24 and the ink is filled in the ink storage portion 16. It functions as a so-called full tank valve and stops the supply of ink into the ink containing portion 16.

When the surface area of the gas permeable film 24 is small, it is necessary to increase the suction pressure in order to shorten the supply time required for supplying the ink. When the suction pressure is increased, the pressure applied to the gas permeable membrane 24 also increases and the edge of the suction port 23 is pressed with a large pressure. Therefore, it is desirable to secure the surface area of the gas permeable membrane 24 as large as possible.

The partition wall 22 is formed in the ink containing portion 16 so as to cover the connection port 21 in an airtight state, and the suction port 23 is provided at a position facing the connection port 21.
The breathable film 24 has an outer peripheral portion along the opening edge of the suction port 23,
For example, they are welded by heat welding.

As shown in FIG. 3, the suction port 23 has a substantially circular cross section on the side of the opening edge adjacent to the ventilation film 24, in which the opening area of the suction port 23 is gradually increased toward the ventilation film 24 side. An arcuate notch 25 is formed. The cutout portion 25 has a curved surface formed with a curvature (R0.5) of approximately 0.5 mm or more. This notch 2
As shown in FIG. 7 of the above-mentioned conventional technique, the gas permeable membrane 24 is largely elastically displaced toward the connection port 21 by
The stress generated by being pressed against the opening edge of the suction port 23 is suppressed.

That is, when the ink reaches the surface of the gas permeable membrane 24 with the ink filled in the ink containing portion 16, a pressure of about 15 kPa is applied, and the recovery portion 9 causes the ink containing portion to fill. As the air in 16 is sucked, the negative pressure that can be generated by the pump 37 of the recovery unit 9 described later is increased. However, since the cutout portion 25 is formed at the opening edge of the suction port 23 of the ventilation film 24, it is prevented from being damaged by the opening edge of the suction port 23 when it is largely elastically displaced toward the connection port 21 side. Has been done.

Further, each ink containing portion 16 of the sub tank 6
Is provided with an ink supply port 27 for supplying ink to the ink absorbers 18a and 18b of each ink containing portion 16 by connecting the joint portion 8 to a side surface portion facing the joint portion 8. There is.

Four joint parts 8 are provided corresponding to each ink accommodating part 16 of the sub tank 6 of the carriage 7, and a supply tube 31 for supplying ink from the main tank 5 to the sub tank 6 is provided. ing.
One end of the supply tube 31 is connected to the ink containing portion 15 of the main tank 5, and the other end of the supply tube 31 is connected to the ink supply port 27 of the carriage 7.
Is provided. The supply connection portion 32 is formed slightly smaller than the inner diameter of the ink supply port 27 and can be inserted into the ink supply port 27.

As shown in FIGS. 1 and 2, the recovery section 9 is brought into contact with the recording head 4 during non-recording, and the recording head 4
35 for protecting the suction tank 23 and the suction port 23 of the sub tank 6
And a pump 37 that sucks air from the inside of the ink containing portion 16 of the sub-tank 6 via the connecting member 36.

As shown in FIG. 1, the transfer mechanism 11 includes a main scanning motor 40 for moving the carriage 7 in the main scanning direction,
A first pulley 41 rotatably driven by the main scanning motor 40, a timing belt 42 driven by the first pulley 41, a second pulley 43 movably supporting the timing belt 42, and a carriage. 7
And a drive shaft 44 for movably supporting the.

Further, the carriage 7 is provided with a connecting portion 28 which is fixedly connected to a timing belt of the transfer mechanism 11 which will be described later and a bearing portion 29 which is movably supported by the transfer mechanism 11. There is.

Although not shown in detail, the transport mechanism 12 extends from the paper feed port to the recording head 4 side along the direction in which the recording head 4 crosses the main scanning direction, that is, the sub-scanning direction of the sheet 3. A pair of paper feed rollers and a paper feed driven roller 46 that convey the paper 3, a platen 47 that supports the paper 3 recorded by the recording head 4, and a pair of the paper that conveys the paper 3 from the recording head 4 side to the paper ejection port. A paper discharge roller and a paper discharge driven roller are provided.

Although not shown, the ink jet printer also has a supply control section for controlling the suction section so that ink is supplied from the main tank 5 to the sub tank 6.

The operation of supplying ink from the main tank 5 to the sub-tank 6 and the operation of the ventilation film 24 of the sub-tank 6 in the ink jet printer constructed as described above will be described.

First, in the ink jet printer, when a predetermined amount of ink in the sub tank 6 is used, the transfer mechanism 1
1, the carriage 7 in which the recording head 4 and the sub tank 6 are integrally provided is moved to the home position. The inkjet printer drives the recovery unit 9 and the joint unit 8 at the home position,
The nozzle of the recording head 4 is airtightly closed by the cap 35 of the recovery unit 9, and the supply connection unit 3 of the supply tube 31 of the joint unit 8 is connected to the ink supply port 27.
2 are connected and communicated with the main tank 5. Also,
At this time, in the sub tank 6, the connection member 36 of the recovery unit 9 is connected to the connection port 21 so that the ink storage unit 16 is connected to the pump 3.
The vent hole 19 is closed in an airtight state by a valve mechanism or the like (not shown).

In this state, the ink jet printer is
By driving the pump 37 to suck the air in the sub tank 6, the ink in the main tank 5 is supplied into the sub tank 6 through the joint portion 8 and the ink supply port 27. Then, in the inkjet printer, when the liquid level of the ink supplied into the sub-tank 6, that is, the so-called water level reaches the surface of the ventilation film 24, the ventilation film 24 functions as a control valve, so that the supply of ink is stopped.

As described above, according to the ink jet printer, since the notch 25 is formed at the opening edge of the suction port 23, when the ventilation film 24 is largely elastically displaced toward the connection port 21 side, suction is performed. Since the stress generated when pressed against the opening edge of the mouth 23 is suppressed, the opening edge of the suction port 23 can prevent damage. Then, according to this inkjet printer, the reliability of the ink supply operation can be improved.

(Second Embodiment) Next, another sub tank provided in the carriage 7 of the ink jet printer will be described with reference to the drawings. In addition, in the other sub-tanks, the same members as those in the above-mentioned sub-tank 6 are denoted by the same reference numerals and the description thereof will be omitted. In addition, this sub-tank is different in that the notch 25 is not formed in the suction port 23.

As shown in FIG. 4, another sub tank 56 is provided.
Is a ventilation film 24 and a ventilation member 5 that close the suction port 23.
Have 7. The gas permeable membrane 24 is formed by stretching a porous material such as polytetrafluoroethylene (PTFE) and intertwining the fibers.

The ventilation member 57 has a mechanical strength larger than that of the ventilation film 24 such as a porous plastic or a metal mesh, and is made of a material having air permeability.
The surface area is approximately equal to the surface area of No. 4.

The ventilation film 24 and the ventilation member 57 are
In the superposed state, the ventilation member 57 is connected to the ink supply port 2
It is joined to the suction port 23 by being heat-welded in a direction to be adjacent to 7. Therefore, since the ventilation film 57 is suppressed from being largely elastically displaced toward the connection port 21 side by the ventilation member 57, the stress generated by being pressed by the opening edge of the suction port 23 is suppressed.

According to the above-described sub tank 56, the ventilation member 57 having a mechanical strength higher than that of the gas permeable membrane 24 suppresses the displacement amount of the gas permeable membrane 24 elastically displaced toward the connection port 21 side, so that the gas permeable membrane 24 is sucked. It is possible to prevent breakage due to the opening edge of the mouth 23.

(Third Embodiment) Next, still another sub-tank having a displacement restricting member for restricting the amount of elastic displacement of the gas permeable membrane 24 will be described with reference to the drawings.
In addition, in this other sub-tank, the same members as those in the above-mentioned sub-tank 6 are designated by the same reference numerals, and the description thereof will be omitted. In addition, this sub-tank is different in that the notch 25 is not formed in the suction port 23.

As shown in FIG. 5, still another sub tank 6
6, the connection port 21 is provided with a displacement regulation member 67 that regulates the displacement amount by which the gas permeable membrane 24 is elastically displaced. The displacement restricting member 67 has a substantially cylindrical contact portion 68 whose tip is in contact with the gas permeable membrane 24, and an elastic flat plate-like biasing member that biases the contact portion 68 so as to restrict the displacement of the contact portion 68. And a part 69.

The abutting portion 68 is located substantially at the center of the suction port 23, and the tip portion is inserted into the suction port 23. A curved surface is formed at the tip of the contact portion 68, and the contact portion 68 is not sharpened. The urging portion 69 is a packing 70.
It is arranged so as to close the connection port 21 with a pinch in between and is fixed by a screw 71.

Further, the displacement regulating member 67 is provided with a ventilation path 72 for ventilating the air in the ink containing portion 16 from the tip end side of the abutting portion 68 to the urging portion. The passage 72 communicates with the pump 37 of the recovery unit 9.
The ventilation passage 72 is formed in a substantially Y shape having two ventilation holes 73 on the tip side of the contact portion 68.

Although the displacement restricting member 67 described above has one contact portion 68, it has a plurality of contact portions 6.
8 may be provided, and the displacement amount in which the gas permeable membrane 24 is elastically displaced can be suppressed more favorably.

According to the sub tank 66 described above, the displacement regulating member 67 suppresses the amount of displacement in which the gas permeable membrane 24 is elastically displaced toward the connection port 21 side, so that the gas permeable membrane 24 is damaged by the opening edge of the suction port 23. Can be prevented.

(Fourth Embodiment) Finally, regarding another ink jet printer provided with another recovery section having a pressure regulating valve mechanism for suppressing the pressure applied to the gas permeable membrane 24,
A description will be given with reference to the drawings. Since the other inkjet printers have almost the same configuration as the inkjet printer of the first embodiment, the same members are designated by the same reference numerals and the description thereof is omitted. Further, the sub-tank of this inkjet printer is different in that the notch 25 is not formed in the suction port 23.

As shown in FIG. 6, the recovery section 75 provided in another ink jet printer is located at a position branched from the flow path 77 between the connection member 36 connected to the suction port 23 of the sub tank 76 and the pump 37. The pressure adjusting valve mechanism 80 is provided and suppresses the pressure applied to the gas permeable membrane 24.

The pressure adjusting valve mechanism 80 is provided with an adjusting chamber 81 communicating with the flow path 77, a vent hole 82 provided in the adjusting chamber 81 for ventilating the outside air, and the vent hole 82 capable of opening and closing. The adjusting valve 83 and an urging spring (not shown) that urges the ventilation hole 82 to be closed by the adjusting valve 83.

In the pressure adjusting valve mechanism 80, when the negative pressure of the air sucked from the ink containing portion 16 in the flow path rises above a predetermined pressure, the adjusting valve 83 applies the urging force of the urging spring. The air is vented and the outside air flows in through the ventilation holes 82.
For this reason, the negative pressure in the flow path 77 is prevented from rising above a predetermined pressure, so that the ventilation film 24 is prevented from being largely elastically displaced and pressed by the opening edge of the suction port 23. In the pressure adjusting valve mechanism 80, the negative pressure at which the adjusting valve 83 opens the vent hole 82 is set to the negative pressure generated when the inside of the sub tank 76 is filled with the supplied ink.

According to the other ink jet printer described above, by providing the pressure adjusting valve mechanism 80, the displacement amount by which the gas permeable membrane 24 is elastically displaced toward the connection port 21 side is adjusted, so that the gas permeable film 24 is sucked into the suction port 23. It is possible to prevent damage due to the opening edge of the.

In the above-described ink jet printer according to this embodiment, the sub-tank 6 is provided integrally with the carriage 7, but the sub-tank 6 may be detachably attached to the carriage 7. Good.

Further, in the ink jet printer of each of the above-mentioned embodiments, the notch portion 25,
Ventilation member 57, displacement regulating member 67, pressure regulating valve mechanism 80
However, the gas permeable membrane 24 may be provided by combining a plurality of stress suppressing means.
Can be more reliably prevented from being damaged.

[0072]

As described above, according to the ink jet printer and the ink tank of the present invention, the stress suppressing means suppresses the stress generated when the gas permeable film is pressed against the opening edge of the suction port. It is possible to prevent breakage and damage of the ventilation film by the opening edge, and it is possible to improve the reliability of the ink supply operation.

[Brief description of drawings]

FIG. 1 is a perspective view showing an inkjet printer according to the present invention.

FIG. 2 is a schematic view shown for explaining a main part of the inkjet printer.

FIG. 3 is a schematic view shown for explaining a sub tank included in the inkjet printer.

FIG. 4 is a schematic diagram shown for explaining another sub-tank.

FIG. 5 is a schematic diagram shown for explaining still another sub-tank.

FIG. 6 is a schematic diagram shown for explaining another inkjet printer according to the present invention.

FIG. 7 is a schematic diagram shown for explaining a conventional inkjet printer.

[Explanation of symbols]

3 sheets 4 recording head 5 main tank 6 sub tank 7 carriage 8 joint section 9 Recovery Department 11 Transfer mechanism 12 Transport mechanism 16 Ink storage section 23 Suction port 24 breathable membrane 25 Notch 35 cap 57 Ventilation member 67 Displacement regulating member 80 Pressure regulating valve mechanism

Claims (15)

[Claims] 1. A recording head for ejecting and recording ink on a recording medium, a main tank for accommodating the ink to be supplied to the recording head, and an ink accommodating portion for accommodating the ink supplied from the main tank, Ink from the main tank to the sub-tank having a suction port for sucking air in the ink containing portion, a sub-tank provided so as to close the suction port and having a characteristic of transmitting only gas And a suction means for sucking air in the ink containing portion of the sub-tank through the suction port, and the negative pressure by the suction means causes the breathable film to press against the opening edge of the suction port. An ink jet printer comprising: a stress suppressing unit that suppresses a stress generated by the stress. 2. The ink jet printer according to claim 1, wherein the recording head is mounted on the sub tank. 3. The ink jet printer according to claim 1, wherein the breathable film is made of a porous material. 4. The stress suppressing means has a notch on the side of the opening edge of the suction port adjacent to the gas permeable membrane, the cutout portion gradually increasing the opening area of the suction port toward the gas permeable membrane side. The inkjet printer according to claim 1, wherein 5. The inkjet printer according to claim 4, wherein the cutout portion is formed in a curved shape or in a shape forming an obtuse angle with respect to a joint surface to which the outer peripheral portion of the gas permeable membrane is joined. 6. The stress suppressing means has a ventilation member that is provided so as to overlap the main surface of the gas permeable membrane on the side of the suction port, has a mechanical strength greater than that of the gas permeable membrane, and is permeable to gas. The inkjet printer according to claim 1. 7. The ink jet printer according to claim 1, wherein the stress suppressing unit has a displacement regulating member that is in contact with the main surface of the gas permeable membrane and regulates the amount of elastic displacement of the gas permeable membrane. . 8. The ink jet printer according to claim 1, wherein the stress suppressing unit has a control member that controls the suction pressure of the suction unit so as not to rise above a predetermined pressure. 9. The ink jet printer according to claim 8, wherein the control member is a pressure adjusting valve that controls the suction pressure of the suction means so as not to rise above a predetermined pressure. 10. An ink tank mounted on an ink jet printer having a main tank for containing ink to be supplied to a recording head, the ink containing portion containing ink supplied from the main tank, and an ink jet printer side. A suction port for sucking the air in the ink containing section by the suction means, a gas permeable film which is provided so as to close the suction port and has a characteristic of allowing only gas to pass, and the gas permeable film is formed by the suction means. An ink tank comprising: a stress suppressing unit that suppresses a stress that is pressed against the opening edge of the suction port by a negative pressure. 11. The ink tank according to claim 10, further comprising a recording head that ejects ink onto a recording medium to record the ink. 12. The stress suppressing means has a cutout portion on the side of the opening edge of the suction port adjacent to the gas permeable membrane, the cutout portion gradually increasing the opening area of the suction port toward the gas permeable membrane side. The ink tank according to claim 10, wherein: 13. The ink tank according to claim 12, wherein the cutout portion is formed in a curved surface shape or an obtuse angle with respect to a joint surface to which the outer peripheral portion of the gas permeable membrane is joined. 14. The stress suppressing means has a ventilation member that is provided so as to overlap with the main surface of the gas permeable membrane on the suction port side and has a mechanical strength greater than that of the gas permeable membrane and that allows gas to permeate therethrough. Item 10. The ink tank according to item 10. 15. The ink tank according to claim 10, wherein the stress suppressing unit has a displacement regulating member that is in contact with the main surface of the gas permeable membrane and regulates the amount of elastic displacement of the gas permeable membrane. .