JP2002144601A - Sub-ink tank and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sub-ink tank which can deal with high speed printing and to stabilize a negative pressure being generated in the sub-ink tank. SOLUTION: The sub-ink tank 9 comprises a first liquid chamber 31 containing an ink absorber 24 which can be impregnated with ink, an ink storing section 27 communicating with the first liquid chamber 31 through a communicating section 26 formed between a partition wall 38 and a barrier wall 34, a second liquid chamber 32 communicating with the ink storing section 27 through an opening 37 thereof and containing ink, and an ink jet recording head 4 for ejecting ink provided on the lower surface 35 side. Ink is present constantly at the ink storing section 27 and the communicating section 26 is filled constantly with ink. When air is sucked from the second liquid chamber 32 through an air exhaust tube 5 connected with an air exhaust opening 5a, the second liquid chamber 32 is refilled with ink through an ink tube 10 connected with a supply opening 10a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a sub-ink tank for storing ink and an ink jet recording apparatus.

[0002] In the present specification, the term "raw ink" refers to ink simply stored in a container or the like. In addition, “semi-lived ink” refers to ink in a state of being impregnated and held in an ink absorber described later.

[0003]

2. Description of the Related Art Ink jet recording apparatuses which perform recording by ejecting ink onto a recording medium have been widely used in recent years because recording sounds are very quiet, the apparatus is small and inexpensive. An ink jet recording head used for such an ink jet recording apparatus, which ejects ink, uses a piezoelectric element. By applying a current to the piezoelectric element, the ink is formed on the ink jet recording head by a deforming force of the piezoelectric element. Some are discharged from the discharged outlet. In addition, a heater board having a plurality of electrothermal converters, a plurality of ink flow paths corresponding to the electrothermal converters, and a common liquid chamber for supplying ink to each ink flow path are formed. A bubble jet (registered trademark) is used in which a current is applied to each of the electrothermal converters to generate heat by causing a current to flow through each of the electrothermal converters to cause film boiling of the ink and to discharge the ink by the bubbling force. And others.

Further, as a form of an ink jet recording head attached to the ink jet recording apparatus, there is a form of an ink jet head cartridge in which an ink tank containing ink therein and an ink jet recording head are integrated. In this case, Since the ink jet head cartridge is replaced when the ink in the ink tank runs out, if the ink jet recording head becomes high-performance and expensive, the maintenance cost of the ink jet recording device will increase, In some cases, disposal of a possible inkjet recording head may cause environmental problems and the like.

Therefore, an ink jet head cartridge in which only the ink tank is replaced when the ink runs out has been actively proposed in recent years. These ink-jet head cartridges, which are called on-carriage type, are suitable for reducing the size of the ink jet recording device because the ink tank can be replaced even if the ink capacity is reduced by downsizing the ink tank. ing.

On the other hand, for a user who prints in large quantities,
It is necessary to use an ink tank having a large ink capacity in order to reduce the number of replacements of the ink tank and to reduce the running cost, and to increase the scanning speed of the carriage in order to increase the recording speed.

However, in order to increase the capacity of the ink tank and to increase the speed of recording, the on-carriage method places too much load on the carriage. For this reason, there has been proposed an ink jet recording apparatus adopting a pit-in system in which the capacity of an ink tank mounted on a carriage is reduced and the ink tank is automatically refilled with ink during non-recording.
In addition, a main ink tank having a large capacity is provided in a place other than the carriage of the inkjet recording apparatus, that is, in a place that does not affect the recording speed of the inkjet recording apparatus, and a tube is supplied from the main ink tank to the inkjet recording head by a tube. An ink jet recording apparatus using a supply system has also been proposed.

The ink jet recording apparatus using the pit-in method or the tube supply method described above requires a sub-ink tank for storing a certain amount of ink immediately before the ink-jet recording head.

In the case of the pit-in system, an ink tank section for holding ink used for recording is required until the ink is supplied at the supply position, and therefore, a configuration including a sub-ink tank is required. .

In the case of a tube supply system in a serial printer that performs recording at an arbitrary position on a recording medium by reciprocating scanning of a carriage, it is used to supply ink from a main ink tank to a sub-ink tank by moving the carriage. The ink in the tube has inertia. As a result, the ink pressure inside the tube that fluctuates from time to time causes pressure fluctuations in the ink inside the ink jet recording head, and it may not be possible to perform stable ejection by the ink jet recording head. Therefore,
In order to eliminate the influence of such pressure fluctuation, it is better that the ink supply tube and the ink jet recording head do not communicate with each other at the time of recording. For this reason, as in the pit-in method, the ink used for recording is held. Provided with a sub ink tank as an ink tank unit for this purpose.

When printing is performed by the ink jet head cartridge having such a configuration, the negative pressure in the sub ink tank rises more than necessary due to consumption of the ink. It is necessary to provide a negative pressure generating means for giving an appropriate negative pressure. As the negative pressure generating means, there are various means such as a means for generating a negative pressure using a repulsive force of a spring and a means for generating a negative pressure by a meniscus at a gas-liquid interface. Among them, the method of generating a negative pressure by the meniscus is very reliable because the change in the negative pressure is very small and the negative pressure applied to the inkjet recording head is stable even when the ink in the sub ink tank is consumed. It is possible to perform highly reliable recording stably.

[0012]

In order to increase the recording speed and to reduce the number of times ink is supplied, the above-mentioned sub-ink tank needs to be produced as much as possible in order to reduce the load on the carriage and the size of the ink jet recording apparatus. In order to accommodate a large amount of ink and reduce the size of the sub ink tank itself, it is required to improve the volumetric efficiency.

As an example of increasing the volumetric efficiency of the sub ink tank for an ink jet recording apparatus using a tube supply system, an ink jet head cartridge as shown in FIG. 9 can be considered.

The sub-ink tank 409 has a first liquid chamber 431 for accommodating an ink absorber 424 for impregnating and holding the ink as semi-raw ink and a second liquid chamber 432 for accommodating the raw ink in a horizontal direction (FIG. 9). (The middle X direction), and the capacity of the first liquid chamber 431 is increased by the second liquid chamber 4.
The volume efficiency is enhanced by making the volume smaller than that of the volume 32. An ink jet recording head 404 for discharging ink is provided on the lower surface 435 side, and discharges ink in a downward arrow direction in the drawing. A communication part 426 for communicating the first liquid chamber 431 with the second liquid chamber 432 is formed between the partition wall 438 and the lower surface 435. Since the communication portion 426 is formed so as to face the lower surface 435 as described above, the communication portion 426 is always filled with ink, and a stable negative pressure due to meniscus can be generated. Further, an air discharge tube 405 for discharging the air in the second liquid chamber 432 is connected to the upper surface 436.

However, the following problem may occur in the sub-ink tank 409 having the structure shown in FIG.

First, there may be a problem regarding the connection position of the ink tube to the sub ink tank.

In general, as shown in FIG. 10, which is a schematic view showing an example of a layout of each part of an ink jet recording apparatus, a main ink tank 402 is provided with a layout of a conveying section for conveying recording paper 412 in the ink jet recording apparatus. From the relationship, it is conceivable that the ink jet recording apparatus is disposed obliquely downward rightward with respect to the sub ink tank 409 when viewed from the side. In this case, if the connection position of the ink tube is on the front surface 401 side, the ink tube interferes with the platen roller 418 or the like constituting the transport unit, and if the connection position of the ink tube is on the lower surface 435, the recording tube 412 interferes. Although there are no parts or the like that interfere with the upper surface 436, it is not preferable to provide a protrusion further upward in addition to the air discharge tube 405 in terms of reducing the size of the ink jet recording apparatus. From such a viewpoint, it is preferable to connect the ink tube to the rear surface 437 side. However, since the first liquid chamber 431 is provided in the sub ink tank 409, the ink is directly supplied to the second liquid chamber 432. Can not supply.

Further, the sub ink tank 409 as shown in FIG. 9 has a configuration in which the first liquid chamber 431 and the second liquid chamber 432 are arranged in parallel in the horizontal direction. It is possible that it will be.

As described above, in the configuration in which the first liquid chamber 431 and the second liquid chamber 432 are arranged in parallel in the horizontal direction, the volume efficiency can be increased, but the above-described problem may occur. is there.

On the other hand, the ink tube 503 can be connected to the back surface 537 like a sub-ink tank 509 shown in FIG. 11 which is a side sectional view of another example of an ink-jet head cartridge in which the volume efficiency of the sub-ink tank is increased. When the first liquid chamber 531 is disposed above, the ink interface 502 is located below the communication part 526, that is, the communication part 5
When the state is such that the air 26 is exposed to the air in the second liquid chamber 532, the communication portion 526 cannot generate a negative pressure due to the meniscus. When air passes through the ink absorber 524, the air communication port 523, the ink absorber 524, the communication portion 526, and the second liquid chamber 532 are formed.
Is formed, the pressure in the second liquid chamber 532 becomes the atmospheric pressure, and it becomes impossible to generate a negative pressure in the second liquid chamber 532. Thus, the first liquid chamber 53 in the sub ink tank 509
Although the layout 1 is a very advantageous layout in increasing the volumetric efficiency, as described above, the formation of the meniscus in the communication portion 526 is affected by the interface of the ink in the second liquid chamber 532, This is not suitable for practical use.

Accordingly, an object of the present invention is to provide a sub-ink tank and an ink-jet recording apparatus which can generate a stable negative pressure and can speed up recording.

[0022]

In order to achieve the above object, a sub-ink tank according to the present invention is a sub-ink tank which can be refilled with ink. A first liquid chamber containing a negative pressure generating member for generating pressure, an ink supply unit for supplying ink to the outside, and a second liquid chamber containing ink for supplying to the ink supply unit. An ink storage unit having an opening communicating with the second liquid chamber, the ink storage unit storing ink so that an ink interface independent of an ink interface in the second liquid chamber can be formed; It is characterized by having a communication part arranged so that the inside may be filled up with the ink stored in the storage part, and connecting the ink storage part and the first liquid chamber.

As described above, in the sub-ink tank of the present invention, the first liquid chamber and the second liquid chamber are provided with the communicating portion arranged so that the inside is filled with the ink stored in the ink storing portion. Is communicated through. Since the interface of the ink stored in the ink storage section is formed independently of the interface of the ink in the second liquid chamber, the inside of the communication section can be maintained in a state filled with ink. For this reason, even if the ink in the second liquid chamber is consumed by being supplied to the ink supply unit, even if the interface of the ink in the second liquid chamber falls below the position where the communication part is formed,
The communication portion is not exposed to the air in the second liquid chamber. Accordingly, when examining the layout of the first liquid chamber that houses the negative pressure generating member in the sub ink tank,
It is not necessary to consider the influence of the interface of the ink in the liquid chamber, so that the degree of freedom of the layout of the first liquid chamber is increased, and the volume of the second liquid chamber that stores the raw ink is reduced to accommodate the semi-raw ink. It can be made larger than the volume of the first liquid chamber.

A replenishing port for refilling ink may be formed in the second liquid chamber, or the second liquid chamber may be connected to an external opening / closing means by a second liquid chamber. An air outlet for discharging room air may be formed, and the air outlet may have a film that is permeable but does not allow ink to pass through.

Further, in the ink supply section, the bottom surface of the first liquid chamber may not include the bottom surface of the sub ink tank.

The opening of the ink reservoir does not allow the passage of ink, but may have a gas permeable membrane. The opening of the ink reservoir extends toward the inside of the ink reservoir. It has a lid having a hollow pipe, the communication between the second liquid chamber and the ink storage section may be through a hollow pipe, and the opening of the ink storage section may be
It may have a lid having an opening and a stopper for closing the opening using gravity. With such a configuration, even when the sub ink tank is turned upside down such that the bottom surface is upward with respect to the state used for normal printing, ink leaks from the opening of the ink storage unit. Since there is no such a problem or the leakage of ink can be reduced, it is possible to secure enough ink to fill the communicating portion.

Further, the air outlet may have a film which is permeable but does not allow ink to pass through.
In this case, in filling the ink, the ink does not rise above this film, so that it is possible to easily fill the sub ink tank with the ink.

An ink jet recording apparatus of the present invention holds an ink jet head cartridge having the sub ink tank of the present invention and an ink jet recording head for discharging the ink supplied from the ink supply section.
It has a carriage supported so as to be able to reciprocate along the surface of the recording medium, and performs recording on the recording medium by discharging ink from the inkjet recording head unit based on an electric signal for discharging ink. And

In the ink jet recording apparatus of the present invention configured as described above, the volume of the second liquid chamber containing the raw ink can be made larger than the volume of the first liquid chamber containing the semi-raw ink. Since the carriage for holding the ink jet head cartridge having the sub ink tank according to the present invention is provided, the number of times required for refilling the ink can be reduced.

Further, the ink jet recording apparatus of the present invention may be configured to detachably hold a main ink tank which stores ink for replenishing the sub ink tank with ink.

Further, the ink jet recording apparatus of the present invention may have means for making the sub ink tank and the main ink tank communicate with each other at the time of replenishment and not with the ink at the time of recording. The second liquid chamber and the outside
It may have a means for communicating when replenishing and not for recording.

Further, the ink jet recording apparatus of the present invention can be used when recording has not been performed for a predetermined time or more.
It may have a means for discharging air from the air discharge port and supplying ink from the supply port.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a schematic perspective view for explaining the structure of an ink jet recording apparatus according to the present embodiment. The ink jet recording apparatus shown in FIG. 1 is of a type in which an ink tank fixed to the ink jet recording apparatus and a sub ink tank mounted on a carriage are connected by a tube, and ink is supplied to an ink jet recording head.

The ink jet recording apparatus according to the present embodiment
An ink jet head cartridge 33 including an ink jet recording head 4 for discharging ink to a recording medium 12 such as a recording paper or a plastic thin plate for recording and a sub ink tank 9 for supplying ink to the ink jet recording head 4 is detachably mounted. A carriage 6 to be mounted, a drive motor 16 for driving the carriage 6, and a recording medium 1
2 in the sub-scanning direction indicated by the arrow A, suction means 20 and cap member 19 as recovery means for recovering the ink ejection characteristics of the ink jet recording head 4, and air in the sub ink tank 9. Air discharging means (not shown) for discharging air.

The carriage 6 is provided with a connector pad (not shown) for the ink jet recording apparatus, which is connected to a connector pad (not shown) for the recording head.

The lead screw 11 is for making the carriage 6 reciprocally scan in the main scanning direction indicated by an arrow B substantially perpendicular to the sub-scanning direction. It serves as a guide when the carriage 6 is scanned. The lead screw 11 is interlocked with forward and reverse rotation of a drive motor 16 via gears 14 and 15, and further has a spiral groove 1 formed in the lead screw 11.
Since the engaging portion 7 is engaged with an engaging portion (not shown) provided on the carriage 6, reciprocal scanning of the carriage 6 in the main scanning direction is performed by driving the drive motor 16.

In the housing 1 of the ink jet recording apparatus, insertion portions into which the yellow ink tank 2a, the magenta ink tank 2b, the cyan ink tank 2c, and the black ink tank 2d are inserted, respectively. 3 are provided, and the ink tanks 2a, 2
b, 2c, and 2d are inserted.

The ink tanks 2a, 2b, 2c, 2d
The sub-ink tank 9 stores ink for supplying ink. In addition, the ink tanks 2a, 2
Each of b, 2c, and 2d has a joint (not shown) that is inserted into the inkjet recording apparatus and communicates with the inkjet recording apparatus, and supplies ink through the joint.

The joint portion is provided with a rubber stopper (not shown). When the ink tanks 2a, 2b, 2c, and 2d are not inserted into the ink jet recording apparatus, the rubber stopper causes the ink tank 2a to move from the joint portion. , 2b,
The structure is such that the ink inside 2c and 2d does not leak outside.

An ink supply needle (not shown) provided on the ink jet recording apparatus side pierces the rubber stopper, and ink in the ink tanks 2a, 2b, 2c and 2d can be drawn out.

Four sub-ink tanks 9 for temporarily storing yellow, magenta, cyan, and black inks
Are connected to the ink tanks 2a, 2b, 2c and 2d via an ink tube 10 serving as an ink supply path. A valve (not shown) is connected to each of the ink tubes 10. When the valves are opened, the ink tubes 10 communicate with each other so that ink can be supplied. When the valves are closed, each of the sub ink tanks 9 and the ink tanks 2a, 2b, 2
The communication states c and 2d are not in a communication state for transmitting the pressure fluctuation of the ink. The sub ink tank 9 is mounted on the carriage 6 and is scanned together with the ink jet recording head 4. On the other hand, the ink tanks 2a, 2b, 2
c and 2d are inserted and fixed in the insertion portion 3 of the housing 1 as described above. Further, the upper surface 3 of the sub ink tank 9
The other end of the air discharge tube 5 whose one end is connected to the air discharge means is connected to the air discharge port 5a (see FIGS. 2 and 3). The air discharge tube 5 is closed by a valve (not shown) except when the air is discharged from the sub ink tank 9, and in this state, the second liquid chamber 32 (see FIG. 3) is not communicated with the outside air. The second liquid chamber 32 communicates with the outside air by opening this valve.

The ink jet recording apparatus is provided with a sensor (not shown) for determining whether or not the ink tanks 2a, 2b, 2c and 2d are mounted. When the ink tube 1 is removed from the ink jet recording apparatus,
The structure is such that the opening end of the ink tube 10 is closed so that the ink inside the ink tube 10 does not leak. If a valve is provided at the open end of the ink tube 10 described above, the prevention of the ink leakage may be performed by closing the valve. In addition, since the ink jet recording apparatus of the present embodiment performs recording while the carriage 6 is reciprocally scanned in the main scanning direction, the ink in the ink tubes 10 uses the ink in the sub ink tank 9 by the inertial force of the scanning of the carriage 6. In some cases, unnecessary ink pressure fluctuation may be applied to the ink jet recording head 4 via the ink jet recording head 4. Therefore, in the ink jet recording apparatus of the present embodiment, at the time of recording, the valve connected to the ink tube 10 is closed to close the sub ink tank 9 and the ink tank 2.
a, 2b, 2c, and 2d are prevented from communicating with each other.

The ink jet recording apparatus according to the present embodiment further has a function of recovering ink ejection characteristics of an ink ejection unit (not shown) provided on the ink jet recording head 4 adjacent to the transport area of the recording medium 12. Recovery means is provided. The recovery means includes a cap member 19 for capping a discharge port (not shown) of the ink jet recording cartridge 4 and a suction means 20 for sucking and recovering the discharge port through an internal opening (not shown) provided in the cap member 19. Consists of The suction means 20 is provided with known transmission means such as a gear 21 and a switching clutch.
The driving force is transmitted from the driving motor 16. The movement of the cap member 19 for capping the ejection port, such as the vertical movement, is performed by a driving force transmitted through the gear 22 or the like, and the cap member 19 is brought into close contact with the portion of the inkjet recording head 4 where the ejection port is provided. Thus, a suction recovery process of the ejection port of the ink jet recording head 4 is performed, and drying of the ink is reduced.

Further, the above-described suction recovery processing not only recovers clogging of the discharge ports of the ink jet recording head 4 but also discharges ink from the sub ink tank 9 to the discharge ports by changing the suction amount. This makes it possible to remove fine dust, air bubbles, and the like from an ink channel (not shown) that connects the sub ink tank 9 and the ejection port. The recovery process of the ink flow path is performed periodically, or a control mechanism (not shown) provided in the inkjet recording apparatus,
This is forcibly performed when the user determines that it is necessary, and it is possible to maintain good formation of a recorded image by this suction recovery processing.

The capping and suction recovery processing described above
This is performed when the carriage 6 is disposed in a region on the home position side where the suction unit 20 and the cap member 19 are provided in the main scanning direction. And
These capping and suction recovery processes are performed singly or in combination in any manner using a well-known timing and sequence.

Next, referring to FIG. 2 which is a schematic perspective view showing the outline of the ink jet head cartridge, and FIG. 3 which is a sectional view of the ink jet head cartridge shown in FIG. Will be described.

As shown in FIG. 2, an ink tube 10 is attached to a supply port 10a formed in the lower portion of the back surface 37 of the sub ink tank 9, and an air discharge port 5a formed in the upper surface 36 is provided. An air discharge tube 5 is attached.

As shown in FIG. 3, the sub-ink tank 9 of the present embodiment includes a first liquid chamber 31 containing an ink absorber 24 capable of holding ink impregnated as semi-living ink, a partition wall 38, a partition wall 34 and And a communication portion 26 that does not have the lower surface 35 as a part of the wall surface and is connected to the first liquid chamber 31 through the communication portion 26 and that stores the raw ink. 27, a second liquid chamber 32 for storing raw ink, which communicates with the ink reservoir 27 through an opening 41 formed in the ink reservoir 27, and an ink jet for discharging ink provided on the lower surface 35 side And a recording head 4.

The first liquid chamber 31 has an atmosphere communication port 23 communicating with the atmosphere. Also, the first liquid chamber 31
Is substantially separated from the ink reservoir 27 and the second liquid chamber 32 except for the communication part 26 by the partition wall 38 and the partition wall 34, and is located above and behind the sub-ink tank 9. It is arranged on the 37 side. First liquid chamber 31
Above the sub ink tank 9 and the back surface 3
The arrangement on the side 7 allows the supply port 10a to be formed below the back surface 37 at a position that does not interfere with the first liquid chamber 31. And this supply port 10a
Is connected to the ink tube 10 without interfering with the platen roller 18 and the recording medium 12, and an extra space for routing the ink tube 10 in the upper part of the ink jet recording apparatus. By securing, the ink tanks 2a, 2b, 2c,
It can communicate with 2d.

The second liquid chamber 32 has the upper surface 3 as described above.
The air discharge tube 5 is connected to an air discharge port 5 a formed in the tube 6. Further, the second liquid chamber 32 communicates with the ink jet recording head 4 via a filter 8 provided on the lower surface 35 for removing bubbles, dust, and the like.

The ink storage section 27 is composed of a partition wall 34, a side partition wall 39, and a partition wall 38 formed with the communication section 26 below in a side cross section. Has become. For this reason, the second liquid chamber 3
The interface between the ink formed in the ink reservoir 2 and the interface between the ink formed in the ink reservoir 27 can be made independent of each other. That is, even if the interface 40 of the ink is lowered by the consumption of the ink in the second liquid chamber 32, the interface of the ink in the ink storage unit 27 does not lower, and the ink existing in the ink storage unit 27 is always It is possible to maintain a state in which the communication portion 26 is filled, so that the communication portion 26 is not exposed to the air in the sub ink tank 9. The communication portion 26 is provided for the ink absorber 2.
A negative pressure due to a predetermined meniscus is set according to the opening diameter of the communication portion 4 and the communication portion 26.

The volume of the second liquid chamber 32 in the sub ink tank 9 is larger than that of the first liquid chamber 31. For this reason, the half-life ink impregnated and held in the ink absorber 24 in the first liquid chamber 31
A large amount of raw ink held in the second liquid chamber 32 can be secured.

The ink jet recording head 4 has an ink supply path 25 serving as an ink supply path from the second liquid chamber 32.
Are formed, and ink is supplied to the ink jet recording head chip 7 through the ink supply path 25. The ink jet recording head chip 7 has a nozzle (not shown) formed by a not-shown electrothermal converter (heater) as an energy generating means for discharging ink and a nozzle material (orifice plate) made of a resin material. By applying electric energy to the heater, the heater generates heat, and the generated heat causes the ink to foam, and the ink is ejected from an ejection port (not shown) using the foaming energy. I have.

Next, the stabilization of the negative pressure in the sub ink tank 9 at the time of ink consumption will be described.

In the initial sub-ink tank 9 where the ink has not been consumed, the second liquid chamber 32 and the ink storage section 27 are provided.
Is filled with raw ink and the first liquid chamber 31
Inside ink is also held by the ink absorber 24.

By performing recording by discharging ink from the inkjet recording head 4, the second liquid chamber 32 is formed.
The raw ink inside is consumed. As described above, since the air discharge tube 5 is closed at the time of recording, the second liquid chamber 3 is closed.
The negative pressure in the second liquid chamber 32 increases because the interface of the ink in the second liquid chamber 32 is lowered by the amount of consumption of the raw ink in the second liquid chamber 32. At this time, even if the interface of the ink in the second liquid chamber 32 falls below the position of the communication part 26, the ink storage part 27 holds the ink that fills the inside of the communication part 26 with ink. By having the ink storage section 27 in this manner, the communication section 26 is always located below the ink interface, so that there is always ink inside the communication section 26 that can form a desired meniscus.

The negative pressure generated by the meniscus formed in the communication portion 26 by the air introduced from the atmosphere communication port 23 and passing through the ink absorber 24 and the ink, and the ink absorber 24 in the first liquid chamber 31 A negative pressure is generated due to the meniscus in the inside. Here, when the negative pressure in the second liquid chamber 32 exceeds the set value of the negative pressure due to the meniscus, the air supplied from the atmosphere communication port 23 passes through the ink absorber 24 and the meniscus of the communication section 26 And the second liquid chamber 32
The negative pressure in the second liquid chamber 32 is prevented from becoming higher than a predetermined negative pressure by suppressing the increase in the negative pressure in the second liquid chamber 32.

As described above, the sub ink tank 9 of the present embodiment has the ink reservoir 27 so that
Since 6 is always located below the ink interface, there is always enough ink inside the communicating portion 26 to form a desired meniscus. Thereby, even if the ink interface in the second liquid chamber 32 is lower than the position where the communication portion 26 is formed,
An air path for directly communicating the second liquid chamber 32 with the atmosphere is not formed, and a negative pressure due to the meniscus can be stably generated in the communication portion 26. Negative pressure can be generated.

When printing is continued while generating a stable negative pressure and the ink in the second liquid chamber 32 is continuously consumed, the second liquid chamber 32 is filled with air. The amount of the raw ink in the sub ink tank 9 is detected by an interface sensor (not shown) that detects the height of the interface of the ink, and if necessary, the ink is refilled in the sub ink tank 9 by the method described below. Fill. The method of detecting the amount of ink in the sub-ink tank 9 is not limited to the method using a sensor, but may be a method such as dot counting.

Next, a procedure for refilling the sub-ink tank 9 with ink will be described. Here, the description will be made using the ink tank 2a as a representative among the ink tanks 2a, 2b, 2c and 2d.

First, the valve connected to the closed ink tube 10 and the valve connected to the air discharge tube 5 are opened. By opening the valve to which the ink tube 10 is connected, the sub ink tank 9 and the ink tank 2a communicate with each other. By opening the valve to which the air discharge tube 5 is connected, the second liquid chamber of the sub ink tank 9 is opened. 32 communicates with the outside air.

Next, the air in the second liquid chamber 32 is discharged through the air discharge tube 5 by the air discharge means. At this time, the second liquid chamber 3 is connected to the air communication port 23 of the first liquid chamber 31.
The air communication port 23 is sealed to prevent air from being drawn into the inside 2. Further, the ejection port is closed by, for example, a rubber pad or the like so that air is not drawn into the second liquid chamber 32 from the ejection port formed in the inkjet recording head 4. It should be noted that the air discharge speed by the air discharge means and the difference in height between the interface of the raw ink in the second liquid chamber 32 and the interface of the ink in the ink tank 2a, that is, the negative pressure generated by the head of the ink, If the balance with the negative pressure due to the meniscus of the discharge port is adjusted, it is possible to refill the ink in the sub ink tank 9 without closing the discharge port.

As described above, the second air is discharged by the air discharging means.
The air in the liquid chamber 32 is discharged, the negative pressure in the second liquid chamber 32 is increased, and the ink in the ink tank 2a is discharged through the ink tube 10 using the negative pressure. Pull in.

The filling amount of the ink in the second liquid chamber 32 is as follows.
When the air is detected by the interface sensor and the appropriate amount is injected, the air discharge by the air discharge means is stopped, the air discharge tube 5 and the ink tube 10 are closed, and the air communication port 23 is opened. Further, when the discharge port is closed, the discharge port is also opened.

By refilling the ink as described above, the ink jet recording apparatus of this embodiment is again in a recordable state.

The air discharge tube 5 is provided at the base of the sub ink tank 9 on the side of the sub ink tank 9 with a gas permeable but ink permeable film, so that the air in the second liquid chamber 32 can be continuously discharged. Since the ink does not rise above this film, it is possible to easily fill the sub ink tank 9 with the ink. As this film, for example, a film such as Gore-Tex (registered trademark) manufactured by Japan Gore-Tex Corporation may be used.

Further, the ink tank 2a may be arranged at a position higher than the sub ink tank 9.
In this case, the second liquid chamber 32 is formed by the air discharging means.
Even if the ink inside the ink tank 2 is not
The head pressure obtained by making the interface height of the ink in a higher than the interface height of the ink in the second liquid chamber 32 can be used, and only by opening the valve that closed the air discharge tube 5, The ink can be refilled from the ink tank 2a into the second liquid chamber 32.

Further, based on a signal from a circuit (not shown) set so that the above-mentioned refilling is automatically performed when the recording is not performed for a predetermined time, the recording is not performed for a predetermined time. May be performed at the time.

As described above, in the sub-ink tank 9 of the present embodiment, the ink stored in the ink storing section 27 can keep the communication section 26 always filled with ink. In this case, a meniscus can be always formed, and a stable negative pressure can be generated. For this reason, it is not necessary to consider the influence of the interface of the ink in the second liquid chamber 32 with respect to the layout of the first liquid chamber 31. Therefore, the layout of the first liquid chamber 31 in the sub ink tank 9 is not required. The degree of freedom is increased, and a layout with high volumetric efficiency can be realized. Thereby, the volume of the second liquid chamber 32 for storing the raw ink can be made larger than the volume of the first liquid chamber 31 for storing the semi-raw ink,
More ink can be stored in the limited volume of the sub ink tank 9. Therefore, since the number of times of refilling of ink can be reduced, the speed of recording can be increased. (Second Embodiment) FIG. 4 is a partially enlarged side sectional view of an ink reservoir of a sub ink tank according to the present embodiment.

On the upper surface of the ink reservoir 127, there is provided a film 128 that allows gas to permeate but does not allow liquid to permeate.
As the film 128, for example, a material such as Gore-Tex shown in the first embodiment may be used.

Except for the above, the configuration of the sub ink tank 9 of the first embodiment is basically the same as that of the first embodiment, and a detailed description thereof will be omitted. Further, the ink jet recording apparatus using the sub ink tank 109 of the present embodiment is the same as the ink jet recording apparatus described in the first embodiment, and a description thereof will be omitted.

Since the film 128 is provided on the upper surface of the ink storage section 127, the ink is stored in the second position from the ink storage section 128 when the ink jet recording apparatus is turned upside down when the ink jet recording apparatus is transported. Is prevented from spilling into the liquid chamber 132. For this reason, when the ink jet recording apparatus returns to the original recording posture, ink enough to fill the communication section 126 with the ink is secured in the ink storage section 127. The function of generating a negative pressure is not impaired.

As described above, the sub-ink tank 109 of this embodiment can always form a meniscus in the communication portion 126 with the ink stored in the ink storage portion 127, as in the first embodiment. A stable negative pressure can be generated. For this reason, a layout with high volumetric efficiency can be realized, and the volume of the second liquid chamber 132 that stores the raw ink can be increased.
More ink can be stored in the limited volume of the sub ink tank. Therefore, since the number of times of refilling of ink can be reduced, recording can be speeded up. (Third Embodiment) FIG. 5 is a partially enlarged side sectional view of an ink reservoir of a sub ink tank according to the present embodiment.

An upper lid 230 having a pipe 229 extending toward the inside of the ink reservoir 227 is provided on the upper surface of the ink reservoir 227. An opening is formed in the upper lid 230 corresponding to the inner diameter of the pipe 229.

Except for the above, the configuration of the sub ink tank 9 of the first embodiment is basically the same as that of the first embodiment. Further, the ink jet recording apparatus using the sub ink tank 209 of the present embodiment is the same as the ink jet recording apparatus described in the first embodiment, and a description thereof will be omitted.

Since the upper lid 230 having the pipe 229 is provided, the second liquid chamber 232 and the ink reservoir 22 are provided.
7, only the pipe 229 is connected. Therefore, for example, as shown in FIG. 6, even when the sub ink tank 209 is turned upside down, all of the ink in the ink storage section 227 is in the second liquid chamber 232 side. It does not spill out and forms an interface at a height equal to or lower than the end 231 of the pipe 229 and remains in the ink reservoir 227.

Therefore, similarly to the sub ink tank 109 of the second embodiment, when the sub ink tank 209 returns to the original recording position, the communication portion 226 is provided in the ink storage portion 227. Is secured, the function of generating a negative pressure is not impaired by a change in the attitude of the ink jet recording apparatus.

The length and diameter of the pipe 229 are adjusted such that when the sub-ink tank 209 is returned to the normal position, the ink is left in the ink reservoir 227 to the extent that the ink is present in the communication portion 226. Anything may be used as long as it is appropriate.

As described above, the sub ink tank 209 of this embodiment is similar to the first and second embodiments,
The ink stored in the ink storage unit 227 causes the communication unit 2
A meniscus can always be formed on 26 and a stable negative pressure can be generated. For this reason, a layout with high volume efficiency can be realized, and the volume of the second liquid chamber 232 containing the raw ink can be increased, so that more ink can be stored in the limited volume of the sub ink tank. It can be accommodated. Therefore, the number of times of refilling of ink can be reduced, so that printing can be speeded up. (Fourth Embodiment) FIG. 7 is a partially enlarged side sectional view of an ink reservoir of a sub ink tank according to the present embodiment.

A ball 331 having a specific gravity enough to sink into the ink is stored in the ink storage section 327. On the upper surface of the ink storage section 327, the minimum diameter of the ball 331, through which the ball 331 cannot pass, is stored. An upper lid 330 in which a hole 329 having a smaller diameter is formed is provided. The second liquid chamber 332 and the ink reservoir 327 communicate with each other through the hole 329.

Except for the above, the configuration is basically the same as that of the sub ink tank 9 of the first embodiment, and a detailed description thereof will be omitted. Further, the ink jet recording apparatus using the sub ink tank 309 of the present embodiment is the same as the ink jet recording apparatus described in the first embodiment, and a description thereof will be omitted.

The ball 331 sinks at the bottom of the ink storage section 327 when the sub ink tank 309 is in the normal posture for performing recording as shown in FIG. Also, the ball 331 is
The communication portion 326 may have any size and shape as long as the communication portion 326 does not hinder gas-liquid exchange.

The sub-ink tank 309 having such a configuration is used.
Is turned upside down as shown in FIG.
1 sinks by gravity toward the upper lid 330 where the hole 329 is formed, and fits into the hole 329 to close the hole 329;
It is possible to prevent all of the ink in the ink storage section 326 from spilling out from the hole 329 to the second liquid chamber 332 side.

For this reason, the sub ink tank 309 of the present embodiment does not impair the function of generating a negative pressure due to a change in the attitude of the ink jet recording apparatus, similarly to the sub ink tanks of the second and third embodiments.

In the present embodiment, the ball 331 has the hole 32
9 is closed, but the present invention is not limited to this, and any configuration may be used as long as the hole 329 is closed using gravity. For example, a configuration in which a weight having a shape capable of closing the hole 329 may be attached to the spring may be adopted. In this case, when the sub ink tank 309 is in a normal posture, the hole 329 is released by being hung down at a position where the weight of the weight and the reaction force of the spring are balanced, and the sub ink tank 309 is turned upside down. If the weight is a hole 329
And prevents the hole 329 from being released by lifting the weight due to the urging force of the spring, so that the ink in the ink storage section 327 can be more reliably secured.

As described above, the sub-ink tank 209 of this embodiment always forms a meniscus in the communication portion 326 with the ink stored in the ink storage portion 327 as in the first to third embodiments. And a stable negative pressure can be generated. For this reason, a layout with high volume efficiency can be realized, and the volume of the second liquid chamber 332 containing the raw ink can be increased, so that more ink can be stored in the limited volume of the sub ink tank. It can be accommodated. Therefore, the number of times of refilling of ink can be reduced, so that printing can be speeded up.

[0087]

As described above, according to the present invention, the communicating portion is provided in the ink storing portion in which the interface of the stored ink can form the interface of the ink independent of the interface of the ink in the second liquid chamber. Is filled with the ink, it is possible to always form a meniscus,
A stable negative pressure can be generated.

Regarding the layout of the first liquid chamber,
Since it is not necessary to consider the influence of the interface of the ink in the second liquid chamber, the degree of freedom of the layout of the first liquid chamber in the sub-ink tank is increased, and the second liquid chamber for storing the raw ink is provided. Can be made larger than the volume of the first liquid chamber containing the semi-lived ink. Therefore, the number of times of refilling of ink can be reduced, so that printing can be speeded up.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a first embodiment of the present invention.

FIG. 2 is a schematic perspective view of the inkjet head cartridge according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of the inkjet head cartridge shown in FIG. 2 taken along line AA.

FIG. 4 is a partially enlarged side sectional view of an ink reservoir of a sub ink tank according to a second embodiment of the present invention.

FIG. 5 is a partially enlarged side sectional view of an ink reservoir of a sub ink tank according to a third embodiment of the present invention.

FIG. 6 is a partially enlarged side sectional view of an ink reservoir when the sub ink tank shown in FIG. 5 is in an upside down state.

FIG. 7 is a partially enlarged side sectional view of an ink reservoir of a sub ink tank according to a fourth embodiment of the present invention.

FIG. 8 is a partially enlarged side sectional view of the ink storage section when the sub ink tank shown in FIG. 7 is in an upside down state.

FIG. 9 is a side sectional view of an example of an ink jet head cartridge in which the volume efficiency of a sub ink tank is improved.

FIG. 10 is a schematic diagram illustrating an example of a layout of each unit of the inkjet recording apparatus.

FIG. 11 is a side sectional view of another example of the ink jet head cartridge in which the volume efficiency of the sub ink tank is improved.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2a, 2b, 2c, 2d Ink tank 3 Insertion part 4 Ink jet recording head 5 Air exhaust tube 5a Air exhaust port 6 Carriage 7 Ink jet recording head chip 8 Filter 9, 109, 209, 309 Sub ink tank 10 Ink Tube 10a Supply port 11 Lead screw 12 Recording medium 13 Guide rail 14, 15, 21, 22 Gear 16 Drive motor 17 Spiral groove 18 Platen roller 19 Cap member 20 Suction means 23 Atmospheric communication port 24 Ink absorber 25 Ink supply path 26 , 126, 226, 326 Communication part 27, 127, 227, 327 Ink storage part 31 First liquid chamber 32, 132, 232, 332 Second liquid chamber 33 Inkjet head cartridge 34 Partition wall 35 Lower surface 36 Upper surface 37 Back surface 3 Partition wall 39 side bulkhead 40 ink interface 41 opening 128 film 229 pipes 230 and 330 upper cover 329 holes 331 Ball

Claims (13)

[Claims] 1. A sub-ink tank which can be refilled with ink, wherein a first liquid chamber for forming a negative pressure generating member for forming a negative pressure, wherein the first liquid chamber has an atmosphere communicating portion communicating with the atmosphere, and an external An ink supply unit for supplying ink to the ink supply unit, a second liquid chamber containing ink to be supplied to the ink supply unit, and an ink interface independent of the ink interface in the second liquid chamber Storing the ink as much as possible, an ink storage section having an opening communicating with the second liquid chamber, disposed so as to be filled with the ink stored in the ink storage section, and A sub-ink tank, comprising: a communication part that communicates the ink storage part with the first liquid chamber. 2. The sub-ink tank according to claim 1, wherein a supply port for refilling ink is formed in the second liquid chamber. 3. The second liquid chamber according to claim 1, wherein the second liquid chamber is provided with an air discharge port for discharging air in the second liquid chamber, the air discharge port being connected to an external opening / closing means. Sub ink tank. 4. The sub-ink tank according to claim 3, wherein the air outlet has a film that is permeable but does not allow ink to pass through. 5. The sub-ink tank according to claim 1, wherein in the ink supply section, a bottom surface of the first liquid chamber does not include a bottom surface of the sub-ink tank. 6. The sub-ink tank according to claim 1, wherein the opening of the ink reservoir has a film that does not allow ink to pass therethrough but has air permeability. 7. The ink storage section has an opening having a lid having a hollow pipe extending toward the inside of the ink storage section, and communication between the second liquid chamber and the ink storage section is established. The sub-ink tank according to any one of claims 1 to 5, wherein the sub-ink tank is provided through the hollow pipe. 8. The sub-ink tank according to claim 1, wherein the opening of the ink storage section includes a lid having an opening, and a stopper for closing the opening by using gravity. . 9. An ink-jet head cartridge comprising the sub-ink tank according to claim 1 and an ink-jet recording head for discharging the ink supplied from the ink supply unit. Having a carriage supported so as to be able to reciprocate along the surface of the recording medium, and performing recording on the recording medium by discharging ink from the inkjet recording head unit based on an electric signal for discharging ink. Characteristic inkjet recording device. 10. The ink jet recording apparatus according to claim 9, wherein a main ink tank for storing ink for replenishing the sub ink tank is detachably held. 11. The ink jet recording apparatus according to claim 10, further comprising means for connecting the sub ink tank and the main ink tank at the time of the replenishment but not at the time of the recording. 12. The ink-jet apparatus according to claim 9, further comprising means for connecting the second liquid chamber and the outside at the time of the replenishment but not at the time of the recording. Recording device. 13. The ink jet printer according to claim 9, further comprising means for discharging air from the air discharge port and supplying ink from the supply port when the recording has not been performed for a predetermined time or more. Item 2. An ink jet recording apparatus according to item 1.