JP2002086756A - Ink tank, ink cartridge and ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect a remaining quantity of ink stored inside an ink tank until the time immediately before the ink runs out. SOLUTION: An ink holder 3 formed of a material swelling when absorbing the ink 2 is fixed to a bottom face inside the ink tank 1 where the ink 2 is stored. It can be detected from a height change because of the swelling/ shrinkage of the ink holder 3 that the remaining quantity of the ink 2 becomes small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink tank for supplying recording ink to an ink jet recording apparatus, and more particularly to an ink cartridge having the ink tank and an ink jet recording apparatus.

[0002]

2. Description of the Related Art An ink jet recording apparatus, which is widely used as a recording apparatus for performing pattern recording of characters, figures, and the like on various articles, vibrates recording ink supplied to an ink head by a piezoelectric vibrator. The ink droplets are ejected while being separated into small ink particles below, and these ink particles are sequentially deflected by a deflecting means arranged in the middle of the ejection path to collide with an object, and are combined by a combination of dots formed at each collision position. It is configured to form a pattern.

In such an ink jet recording apparatus, the supply of ink to the ink head is continuously performed from an ink tank connected to the ink head through a discharge port opened on the bottom surface. The amount of ink stored in the tank is finite, and when the operation of the ink head is continued without noticing that the remaining amount of ink has decreased, air remaining inside the ink head together with the remaining ink is removed. Is sucked in, bubbles are generated,
There is a problem that the above-described ink ejection and the pattern formation due to the ejection are hindered.

[0004] Conventionally, the amount of ink remaining in the ink tank is detected, and when the remaining amount is less than a predetermined minimum amount, a display prompting replacement of the ink tank or replenishment of new ink. In order to prevent the above-mentioned problem from occurring.

In many ink jet recording apparatuses, the ink tank is mounted on a carriage together with an ink head, and is scanned for pattern formation. In this configuration, the ink tank is generated in accordance with the scanning. Since the ink level fluctuation of the ink promotes the suction of the air, an ink absorbing material for absorbing and holding the ink is arranged on the bottom surface of the ink tank to reduce the air suction due to the effect of the liquid level fluctuation. To reduce the occurrence of such malfunctions.

[0006]

However, conventionally, the detection of the remaining amount of ink in the ink tank is generally performed by detecting the liquid level of the ink. There is a problem that accurate detection of the remaining amount cannot be performed when the liquid level fluctuates.To solve the above-described problem, the minimum remaining amount, which is a reference for the display, is set to a high value, and the ink is stored in the ink tank. It is necessary to perform a supplementary display in a state where remains.

Further, in a configuration in which an ink absorber is disposed inside an ink tank in order to eliminate the effect of liquid level fluctuation,
Since it is not possible to detect the remaining amount after the liquid level of the ink is lower than the upper surface of the ink absorber, the minimum remaining amount as a reference for the display is set to a level equivalent to the upper surface of the absorber, It is necessary to display the replenishment in a state where a sufficient amount of ink is absorbed and held in the ink absorber.

As described above, in the prior art, the display prompting the replenishment of the ink is made at the stage when the ink remains in the ink tank, that is, at a stage sufficiently before the ink runs out. When the ink tank is replaced, there is a problem that a large amount of ink is discarded without being used, and at the time of the replacement, there is a possibility that residual ink inside the ink tank leaks out and stains the surroundings.

Further, if the user recognizes that the display is made earlier, the user is left without replacing the ink tank according to the display, thereby preventing air from being sucked into the ink head. There is a possibility that the original purpose cannot be achieved.

[0010] The present invention has been made in view of such circumstances, and it is possible to accurately detect the remaining amount of ink stored therein until immediately before ink runs out.
Provided is an ink tank capable of reducing unnecessary waste of ink at the time of replacement while preventing the occurrence of a problem due to suction of air into an ink head, and an ink cartridge and an ink jet recording apparatus using the ink tank. The purpose is to provide.

[0011]

The ink tank according to the first invention of the present invention is used by being connected to an ink head via a discharge port opened on the bottom surface, and the ink stored inside is discharged from the discharge port. An ink tank supplied to the ink head via the ink head is characterized by comprising an ink holding member made of a material that absorbs and expands the ink and that is fixed to the bottom surface so as to cover at least an opening of the discharge port.

In the present invention, an ink holder made of a material which expands by absorbing ink is fixedly attached to the bottom surface so as to cover the ink discharge port, and the ink holder is attached to the ink container as the absorbed ink decreases. Utilizing the fact that the ink retainer shrinks, the change in height from the bottom surface of the ink holder can be used to accurately determine the shortage of the remaining amount of ink.

The ink tank according to a second aspect of the present invention is formed so as to occupy a part of the bottom surface including the opening of the discharge port.
It is characterized by comprising a storage section for storing the ink holding body by restricting expansion in a direction other than the height direction, and an ink passage communicating the storage section with a non-storage section.

According to the present invention, the ink holding member is housed in a housing portion provided so as to occupy a part of the bottom surface including the discharge port to the ink head, and the ink holding member is generated by absorbing the ink introduced through the ink passage. By restricting the expansion of the ink holder only in the height direction, a change in the height of the ink holder is remarkably caused, and the shortage of the remaining ink amount can be known with higher accuracy.

The ink tank according to the third aspect of the present invention has a
An ink passage according to the invention is provided near the bottom surface.

In the present invention, an ink passage communicating the storage portion and the non-storage portion of the ink holding member is arranged near the bottom surface, and the ink holding member in the storage portion absorbs ink from below.
Penetrated, the ink absorbed and held in the ink holding body,
It is ensured that the liquid is discharged from a discharge port opened at the lower part of the liquid.

The ink tank according to a fourth aspect of the present invention is characterized in that the ink tank includes an empty sensor for detecting a shortage of the remaining amount of the ink based on a change in the height of the ink holder from the bottom surface. .

In the present invention, the change in the height of the ink holder that expands due to the absorption of the ink is used as a medium, and the remaining amount of the ink including the absorbed amount of the ink holder is insufficient, that is,
It detects with high accuracy that it is just before the ink runs out.

The empty sensor for this detection can be constituted by an optical sensor that receives light transmitted through the upper part of the ink holder in the expanded state. The amount of light received by the optical sensor used as an empty sensor is small when the ink holder absorbs a sufficient amount of ink and is in an expanded state, because the upper part of the ink holder blocks the optical path, and conversely absorbs. When the ink holding member is in a contracted state due to the discharge of the ink, it becomes large due to release of the blockage of the optical path by the ink holding member. Therefore, the appropriate arrangement of the optical sensors can accurately detect the shortage of the remaining amount of ink including the amount absorbed by the ink holder.

The ink tank according to the fifth aspect of the present invention has a first
The ink tank according to the present invention includes a near-empty sensor that detects the remaining amount of the ink based on the liquid level of the ink staying in the upper portion of the ink holding body. According to a third aspect of the present invention, there is provided a near-empty sensor for detecting a remaining amount of the ink based on a liquid level of the ink staying in an upper portion of the ink passage.

In these inventions, the remaining amount of ink excluding the amount absorbed by the ink holder is detected by the near empty sensor based on the liquid level of the ink, so that it is possible to notify that the ink is almost exhausted. I do.

This near empty sensor can also be constituted by an optical sensor that receives light transmitted through the ink stagnation portion, similarly to the empty sensor.
The amount of light received by the optical sensor used as the near-empty sensor is reduced by blocking the optical path of the ink when the remaining amount of ink is large and the liquid level is high, and the ink level is low when the ink is low and the liquid level is low. At one time, the ink becomes large due to release of the blockage of the optical path by the ink. Therefore, with the proper arrangement of the optical sensors, it is possible to accurately detect the shortage of the remaining amount of ink excluding the amount absorbed by the ink holder.

An ink cartridge according to a seventh aspect of the present invention is configured such that a predetermined amount of ink is stored inside the ink tank of the first to sixth aspects, and the discharge port is sealed by a sealing means. There is a feature.

According to the present invention, the ink tank capable of detecting the shortage of the remaining amount of ink with high accuracy is configured as an ink cartridge by sealing a predetermined amount of ink therein and sealing the discharge port.

Further, an ink jet recording apparatus according to an eighth aspect of the present invention is the ink jet recording apparatus according to the fourth aspect, an ink head connected to the ink tank via the discharge port, and a shortage of the remaining amount due to the empty sensor. And control means for forcibly stopping the operation of the ink head when the detection of (i) is performed.

According to the present invention, when the empty sensor detects that the ink is in a state immediately before the ink is exhausted, the operation of the ink head is forcibly stopped to reliably prevent the occurrence of a problem due to the suction of air.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is a side sectional view of an ink tank according to the present invention.

The ink tank 1 shown in FIG. 1 is a rectangular box-shaped hollow container formed by resin molding, and a part of the bottom surface of the ink tank 1 is for discharging the ink 2 stored therein. An outlet 10 is opened, and a discharge pipe 11 having a short cylindrical shape is connected to the discharge port 10.

The outlet 10 is also used as an inlet for the ink 2. Inside the ink tank 1, the ink 2 introduced via the outlet pipe 11 and the outlet 10 is provided as shown in FIG. It is stored with a predetermined depth from the bottom,
The illustrated ink tank 1 is configured as an ink cartridge in which the ink 2 stored as described above is sealed so as not to leak out by a film-shaped sealing plate 12 attached to the tip of the discharge pipe 11. . The sealing means for sealing the discharge port 10 is not limited to the seal plate 12, and for example, a sealing cap which is detachably attached to the tip of the discharge pipe 11 by being fitted or screwed is used as the sealing means. Etc., it is possible to adopt an appropriate configuration.

On the bottom surface of the ink tank 1 constructed as described above, an ink holder 3 is arranged so as to cover substantially the entire surface including the discharge port 10. The ink holding member 3 is a thick-walled member made of a material having a property of absorbing a liquid while expanding itself, for example, a porous body made of PVA (polyvinyl alcohol), PVF (polyvinyl formal) or the like. The sheet is cut into a rectangle corresponding to the inner shape of the ink tank 1, and one surface in the thickness direction is fixedly attached to the bottom surface of the ink tank 1 by means such as bonding. The adhesive for fixing the ink holding member 3 made of the above-mentioned material to the bottom surface of the ink tank 1 by bonding includes natural rubber, silicon, acrylic, styrene-butadiene, polyisobutylene, and isobrene. And the like can be used.

The ink holder 3 thus mounted
Will expand by absorbing the ink 2 stored inside the ink tank 1 as described above, and this expansion will occur in the direction of increasing the height from the bottom surface of the ink tank 1 serving as a fixing surface. On one side of the ink tank 1, an empty sensor 4 is provided at a position slightly below the upper surface of the ink holder 3 in the expanded state, and on the other side of the ink tank 1, a near empty position is provided at a position slightly above the upper surface. The sensors 5 are mounted so as to be buried inside the side walls which are partially thickened on each side.

The empty sensor 4 and the near empty sensor 5 are provided with a light emitting portion and a light receiving portion integrally, and emit light from the light emitting portion substantially parallel to the bottom surface of the ink tank 1 as shown by arrows in the drawing. The light is reflected by hitting the inner surface of the other side wall, the reflected light is received by the light receiving section, and the light sensor is arranged to emit a light receiving signal of a level corresponding to the amount of received light.

The empty sensor 4 and the near empty sensor 5 are connected to connectors 40 and 50 provided on the bottom surface of the side wall of the ink tank 1 on each side, for transmitting the light receiving signal to the outside and for emitting the light. External power supply to the unit can be performed via these connectors 40 and 50.

FIG. 2 is a partially cutaway side view showing the operating state of the ink tank 1 configured as described above. As shown, the ink tank 1 is mounted on the other upper side of a carriage 7 having an ink head 6 mounted on one upper side.

At the mounting position of the ink tank 1, there are provided a liquid supply passage 70 projecting from the bottom surface of the ink tank 1 and capable of receiving the discharge pipe 11, and the connectors 40 and 50 located on both sides of the bottom surface. The ink tank 1 is mounted on the carriage 7 by mounting the ink tank 1 on the carriage 7 and the discharge pipe 11 and the connectors 40 and 50. This is realized by positioning the bottom face downward, fitting the discharge pipe 11 to the open end of the liquid supply path 70, and bringing the connectors 40 and 50 into contact with the connectors 71 and 72, respectively.

With the above mounting, the inside of the ink tank 1 is communicated with the liquid supply path 70 through the discharge port 10 and the discharge pipe 11 opened on the bottom surface, and the ink stored in the ink tank 1 is 2 is introduced into the supply port 70 via the discharge port 10 and the discharge pipe 11, and is supplied to the ink head 6 via a liquid supply path (not shown) formed in the carriage 7 continuously with the supply port 70. . The ink 2 thus supplied to the ink head 6 is ejected as fine ink particles by a known operation of the ink head 6 performed while being moved together with the carriage 7, and is ejected to the surface of an object (not shown). Used for pattern formation.

The empty sensor 4 and the near empty sensor 5 attached to the ink tank 1 are connected to a control unit 8 shown as a block in FIG. The light emitting sections of both sensors 4 and 5 are illuminated by power supply from the power supply in response to an operation command from the control section 8, and both sensors 4 and 5 receive light in the light receiving section. The light receiving signal output in accordance with the amount is provided to the control unit 8.

The ink tank 1 is fixed on the carriage 7 while maintaining the above-described mounting mode. For example, the ink tank 1 may be a fixed tank configured to supply the ink 2 from a supply port formed on the upper surface. It is.

As described above, the ink 2 in the ink tank 1 connected to the ink head 6 is gradually consumed and reduced by the above-described operation of the ink head 6. FIG.
FIG. 3 is an explanatory diagram showing a state of a decrease in ink 2 in an ink tank 1 shown in FIG.

The inside of the ink tank 1 immediately after the start of use is
As shown in FIG. 1, the ink 2 is filled over substantially the entire area, the liquid level of the ink 2 is located near the upper surface of the ink tank 1, and the ink holder 3 inside the ink tank 1 Absorbs a sufficient amount of the ink 2 and expands to the maximum. At this time, the light emission of the empty sensor 4 arranged as described above passes through the inside of the ink holder 3 expanded as indicated by the broken arrow in the figure, and the light emission of the near empty sensor 5 As shown by the arrows, the ink penetrates through the ink 2 staying on the ink holding member 3, and is largely absorbed during each transmission. As a result, the light receiving amounts of the light receiving sections of both sensors 4 and 5 are small, and the light receiving signals output by both sensors 4 and 5 are at low level.

FIG. 3A shows a state in which the amount of the ink 2 stored in the ink tank 1 has decreased, and the liquid level of the ink 2 has dropped to near the upper surface of the ink holder 3.
At this time, the ink 2 does not exist on the optical path of the light emitted from the near empty sensor 5, and the light emitted directly reaches the inner surface of the other side wall of the ink tank 1, and the reflected light from the inner surface is transmitted to the light receiving portion. As a result, the received light signal output from the near empty sensor 5 is changed to a high level. If the inner surface of the ink tank 1, at least in the vicinity of the arriving portion of the light emission, is formed as a reflection surface having a high light reflectance, it is possible to remarkably convert the light reception signal to a high level.

On the other hand, at this time, the ink holder 3 absorbs a sufficient amount of the ink 2 and maintains the expanded state, and the expanded ink holder 3 is placed on the optical path of light emission from the empty sensor 4. Existing. Therefore, the light receiving signal output by the empty sensor 4 is kept at a low level.

In the control unit 8, the level of the light received from the near empty sensor 5 is changed to a high level, so that the liquid level of the ink 2 in the ink tank 1 drops to near the upper surface of the ink holder 3. That is,
The controller 8 can recognize that the remaining amount of the ink 2 is low. At this time, for example, the control unit 8 performs an operation of notifying the user that the ink is almost exhausted by turning on a display lamp.

FIG. 3B shows a state in which the ink 2 in the ink tank 1 is further reduced, and the liquid level of the ink 2 is lower than the upper surface of the ink holder 3 and reaches near the bottom surface. ing. At this time, as in FIG.
The ink 2 does not exist on the optical path of light emission of the near empty sensor 5, and the light receiving signal output by the near empty sensor 5 is kept at a high level.

On the other hand, at this time, only the lower part of the ink holder 3 is immersed in the ink 2, the upper part is contracted, and the height H from the bottom of the ink tank 1 is reduced as shown in the figure.
Is lowered, and the empty sensor 4 is deviated from the optical path of light emission. Therefore, the light emitted from the empty sensor 4 reaches the inner surface of the other side wall of the ink tank 1 directly, and the light reflected from the inner surface is caught by the light receiving section, and the light receiving signal output from the empty sensor 4 becomes high level. Convert. If the inner surface of the ink tank 1, at least in the vicinity of the arriving portion of the light emission, is a reflection surface having a high light reflectance,
This makes it possible to significantly change the level of the received light signal to a high level.

In the control section 8, the level of the light received from the empty sensor 4 is changed to a high level, so that the liquid level of the ink 2 inside the ink tank 1 reaches the vicinity of the bottom surface. Can be recognized. At this time, the control unit 8 issues an operation stop command to the ink head 6, and performs an operation of forcibly stopping the ejection of ink by the operation of the ink head 6. Thereby, it is possible to reliably prevent the air from being sucked into the ink head 6 due to the running out of the ink and the trouble caused by the suction.

As described above, in the ink tank 1, the ink holder 3 made of a material which absorbs the ink 2 and expands.
Is fixedly attached to the inner bottom surface, and it is possible to accurately know the shortage of the remaining amount of the ink 2 in the ink tank 1 immediately before the ink runs out, through the change in height due to the expansion of the ink holder 3. It becomes possible.

Further, an empty sensor 4 for detecting a change in the height of the ink holder 3 is provided, and the empty sensor 4 detects the shortage of the remaining amount of the ink 2 including the amount absorbed by the ink holder 3 when the ink runs out. The ink 2 in the ink tank 1 can be almost completely used up while the detection can be performed with high accuracy until immediately before, and the occurrence of troubles caused by the suction of air into the ink head 6 can be prevented. It is possible to prevent the ink 2 from being discarded unnecessarily due to the replacement.

Further, a near empty sensor 5 for detecting the liquid level of the ink 2 staying above the ink holder 3 is provided, and the remaining amount of the ink 2 excluding the amount absorbed by the ink holder 3 is also detected. And it can be notified that the ink is almost exhausted. Further, the empty sensor 4 and the near empty sensor 5 can be simply configured by the optical sensors arranged as described above.

When the empty sensor 4 detects that the remaining amount of ink is insufficient, the operation of the ink head 6 is forcibly stopped in response to an operation command from the control unit 8. It is possible to reliably prevent the occurrence of a trouble due to the suction.

FIG. 4 is a side sectional view showing another embodiment of the ink tank according to the present invention. The ink tank 1 shown in this figure is a rectangular box-shaped hollow container formed by resin molding, similarly to the ink tank 1 shown in FIG. At a part of the bottom surface of the ink tank 1, a discharge port 10 for the ink 2 stored therein is opened, and the discharge port 10 is provided with a discharge pipe 11 having a short cylindrical shape. An ink cartridge is formed by introducing a predetermined amount of ink 2 through a discharge pipe 11 and then sealing the end of the discharge pipe 11 with a seal plate 12.

In the ink tank 1 shown in FIG. 4, there is provided a storage portion 1a which occupies a part of the bottom surface including the opening of the discharge port 10 and is formed by partitioning the upper portion and side portions thereof by partition walls. A thick ink holder 3 made of the above-described material is stored in the storage section 1a,
It is fixed to the bottom surface of the ink tank 1.

The storage section 1a of the ink holder 3 as described above
An ink passage 1c formed by cutting off a part of the side wall near the bottom surface communicates with the other part (non-storage part 1b) inside the ink tank 1, and the ink holder 3 inside the storage part 1a. Absorbs the ink 2 introduced from the non-storage portion 1b through the ink passage 1c. Here, since the ink holder 3 is in a state where the expansion in the lateral direction is restricted by the side wall of the storage portion 1a, the expansion due to the absorption of the ink 2 occurs concentrated in the direction of increasing the height, as shown in the figure. Then, the storage portion 1a expands to fill substantially the entire height.

On the side wall of the ink tank 1 on one side of the storage section 1a, an empty sensor 4 is provided at a position slightly lower than the upper surface of the ink holding body 3 in the expanded state as described above. A near empty sensor 5 is embedded in the side wall at a position slightly higher than the ink passage 1c.

Each of the sensors 4 and 5 has a light-emitting unit and a light-receiving unit integrally as in the embodiment of FIG.
It is configured as an optical sensor arranged to emit a light receiving signal corresponding to both of the reflected light of the light emitted substantially parallel to the bottom surface of the ink tank 1 and the bottom surface of the side wall of the ink tank 1 on each side. Are connected to the connectors 40 and 50 provided for transmitting the light-receiving signal to the outside and supplying power to the light-emitting unit from the outside through the connectors 40 and 50. .

The ink tank 1 configured as described above is
Similar to the ink tank 1 shown in FIG. 1, the ink tank 1 is connected to the ink head 6 through a discharge port 10 opened on the bottom surface, and is used to supply the ink 2 stored therein to the ink head 10 through the discharge port 10. During this use, the ink 2 stored in the ink tank 1 is sequentially consumed and reduced by the above-described operation of the ink head 6. FIG. 5 is an explanatory diagram showing a state of a decrease in the ink 2 in the ink tank 1 shown in FIG.

As shown in FIG. 4, the inside of the ink tank 1 immediately after the start of use is filled with the ink 2 over substantially the entire area including the storage section 1a and the non-storage section 1b. , Located near the upper surface of the ink tank 1,
The ink holder 3 inside 1a absorbs a sufficient amount of the ink 2 introduced through the ink passage 1c and expands to the maximum. At this time, the empty sensor 4 arranged as described above is used.
Is transmitted through the inside of the ink holder 3 expanded as indicated by the broken arrow in the drawing, and the light emitted from the near empty sensor 5 is also transmitted onto the ink holder 3 as indicated by the broken arrow. It will permeate through the stagnant ink 2 and will be largely absorbed during each transmission. As a result,
The light receiving amounts of the light receiving sections of both sensors 4 and 5 are small, and the light receiving signals output by both sensors 4 and 5 have a low level.

FIG. 5A shows a state in which the amount of the ink 2 stored in the ink tank 1 has decreased, and the liquid level of the ink 2 has dropped to near the bottom surface of the non-storage portion 1b. At this time, the ink 2 does not exist on the optical path of light emission of the near empty sensor 5, and the light emission reaches the outer surface of the partition wall forming the storage section 1a, and the light reflected from the partition wall is captured by the light receiving section. As a result, the light receiving signal output from the near empty sensor 5 is changed to a high level. The outer surface of the partition,
If at least the vicinity of the light emission reaching portion is formed as a reflection surface having a high light reflectance, it is possible to remarkably convert the light reception signal to a high level.

At this time, the ink holder 3 absorbs the ink 2 introduced from the ink passage 1c near the bottom surface and maintains the expanded state. Since the ink holding member 3 exists, the light receiving signal output from the empty sensor 4 is kept at a low level. Therefore, the light receiving signal given from the near empty sensor 5 is changed to a high level,
It is possible to know that the remaining amount of the ink 2 is small and the ink is almost exhausted.

FIG. 5B shows a state in which the ink 2 stored in the ink tank 1 is further reduced. At this time, the ink 2 does not exist in the non-storage part 1b at all, and is in a state of being absorbed and held at the lower part of the ink holding body 3 stored in the storage part 1a.

At this time, the ink 2 does not exist on the optical path of light emission of the near empty sensor 5, and the light receiving signal output by the near empty sensor 5 is kept at a high level.
On the other hand, at this time, since only the lower part of the ink holder 3 is immersed in the ink 2, the upper part shrinks inside the storage part 1a, and the height H from the bottom surface decreases as shown in the drawing, It deviates from the optical path of light emission of the empty sensor 4. Accordingly, the light emitted from the empty sensor 4 reaches the inner surface of the partition wall forming the storage portion 1a, and the light reflected from the inner surface is captured by the light receiving portion, and the light receiving signal output from the empty sensor 4 has a high level. Convert to In addition,
If the inner surface of the partition wall, at least in the vicinity of the arriving portion of the light emission, is formed as a reflection surface having a high light reflectance, it is possible to remarkably convert the light reception signal to a high level.

Therefore, when the light receiving signal supplied from the empty sensor 4 is changed to a high level, the remaining amount of the ink 2 in the ink tank 1 becomes insufficient, including the amount absorbed by the ink holding member 3, and the ink immediately before running out of ink. It can know that it is in the state of. Here, the expansion of the ink holder 3 inside the storage section 1a other than in the height direction is restricted, and the height change accompanying the decrease of the absorbed and held ink 2 occurs remarkably. Can be reliably performed. Therefore, it is possible to detect the shortage of the remaining amount of the ink 2 including the absorbed amount of the ink holding member 3 with high accuracy until immediately before the ink runs out, thereby preventing the occurrence of a problem caused by the suction of the air into the ink head 6. In addition, the ink 2 in the ink tank 1 can be almost completely used up, and it is possible to prevent unnecessary disposal of the ink 2 due to unnecessary replacement before the ink runs out.

[0063]

As described in detail above, in the ink tank according to the first aspect of the present invention, an ink holder made of a material that expands by absorbing ink is provided on the bottom surface so as to cover at least the ink discharge port. Since the ink is fixed, the change in height from the bottom surface of the ink holding member makes it possible to know with high accuracy whether or not the remaining amount of ink including the amount absorbed by the ink holding member is insufficient. Can be reliably prevented, and unnecessary waste of ink can be reduced.

In the ink tank according to the second aspect of the present invention, the ink holding body is housed in a housing formed by occupying a part of the bottom surface including the opening of the discharge port, and the height direction of the ink holding body is changed. Since the expansion other than the above is regulated, a change in the height of the ink holder caused by the absorption of ink can be remarkably caused, and the shortage of the remaining amount of ink including the amount absorbed by the ink holder can be more accurately determined. It becomes possible to know.

In the ink tank according to the third aspect of the present invention, the ink passage for guiding ink to the storage portion of the ink holding member is provided near the bottom surface, so that the ink holding member can absorb and hold ink from below. Ink can be reliably discharged from the lower discharge port of the ink holder until immediately before the ink runs out, thereby effectively preventing the occurrence of troubles caused by suction of air into the ink head. Can be.

The ink tank according to the fourth aspect of the present invention includes an empty sensor for detecting a shortage of the remaining amount of ink based on a change in height from the bottom surface of the ink holder. Insufficient ink remaining can be detected with high accuracy until just before the ink runs out, preventing both the occurrence of problems due to the suction of air into the ink head and the unnecessary disposal of ink. Becomes possible. This empty sensor can be simply configured by an optical sensor that receives light transmitted through the upper part of the ink holder in the expanded state.

In the ink tank according to the fifth and sixth aspects of the present invention, the remaining amount of ink is determined based on the liquid level of the ink staying in the upper portion of the ink holding member or the ink level staying in the upper portion of the ink passage. Since the near-empty sensor for detection is provided, the remaining amount of ink excluding the amount absorbed by the ink holding member can be detected together, and can be used to notify that the ink is almost exhausted. This near-empty sensor can be simply configured by an optical sensor that receives light transmitted through the ink retaining portion.

In the ink cartridge according to the seventh aspect of the invention, a predetermined amount of ink is sealed in an ink tank capable of detecting a shortage of the remaining amount of ink with high accuracy, and the discharge port is sealed. It becomes possible to detachably attach and use the ink head to which the ink is to be supplied.

Further, in the ink jet recording apparatus according to the eighth aspect, the operation of the ink head is forcibly stopped when the empty sensor detects that the remaining amount is insufficient. The present invention has an excellent effect, for example, it is possible to surely prevent the suction of air into the ink head, which is caused by this.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an ink tank according to the present invention.

FIG. 2 is a partially broken side view showing a use state of the ink tank shown in FIG.

FIG. 3 is an explanatory diagram showing a state of a decrease in ink in an ink tank shown in FIG. 1;

FIG. 4 is a side sectional view showing another embodiment of the ink tank according to the present invention.

FIG. 5 is an explanatory diagram showing a state of a decrease in ink in the ink tank shown in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink tank 1a Storage part 1b Non-storage part 1c Ink passage 2 Ink 3 Ink holder 4 Empty sensor 5 Near empty sensor 6 Ink head 7 Carriage 8 Control part

Claims (8)

[Claims] 1. An ink tank which is used by being connected to an ink head via a discharge port opened on a bottom surface and supplies ink stored therein to the ink head via the discharge port, wherein the ink tank absorbs the ink. An ink holding member made of a material which expands and is fixed to the bottom surface so as to cover at least the opening of the discharge port. 2. A storage portion formed so as to occupy a part of a bottom surface including an opening of the discharge port, and configured to store the ink holding body by restricting expansion in a direction other than a height direction; The ink tank according to claim 1, further comprising an ink passage communicating with the non-storage portion. 3. The ink tank according to claim 2, wherein the ink passage is provided near the bottom surface. 4. The ink tank according to claim 1, further comprising an empty sensor for detecting a shortage of the remaining amount of the ink based on a change in height of the ink holding member from the bottom surface. 5. The ink tank according to claim 1, further comprising a near empty sensor that detects a remaining amount of the ink based on a liquid level of the ink staying in an upper portion of the ink holding body. 6. The ink tank according to claim 2, further comprising a near empty sensor for detecting a remaining amount of the ink based on a liquid level of the ink staying in an upper portion of the ink passage. 7. The ink tank according to claim 1, wherein a predetermined amount of ink is stored in the ink tank, and the discharge port is sealed by a sealing means. Ink cartridge. 8. The ink tank according to claim 4, an ink head connected to the ink tank via the discharge port, and an operation of the ink head when the empty sensor detects that the remaining amount is insufficient. And a control means for forcibly stopping the recording.