JP2001315350A - Negative pressure sustaining mechanism for ink container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for evenly balancing the negative pressure of an ink 2 supplied to an ink tank 3, and the bubbling force by a heater in a nozzle for achieving a high image quality of a recorded image by an ink-jet recording device. SOLUTION: This device comprises an ink tank 3 with the airtight property with respect to the external air, communicating with a recording head 1 supply opening and a negative pressure container 4, a negative pressure container 4 communicating with the internal air at an upper part of the tank 3, stretchable in the vertical direction, with the internal capacity changeable and the upper end fixed, and a weight 6 on the lower surface of the negative pressure container 4, wherein the capacity of the negative pressure container 4 can be enlarged by the self weight of the weight 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink supply container, and more particularly, to a negative pressure holding mechanism for an ink container for maintaining an ink supplied to a recording head of an ink jet recording apparatus at an appropriate negative pressure.

[0002]

2. Description of the Related Art In recent years, in the field of recording apparatuses (printers), an ink jet recording system has become mainstream. The ink-jet recording method is used not only for a printer but also for a copying machine, a facsimile, and the like because a recording mechanism is small, cost can be reduced, and color printing is easy.

[0003] The recording head of the ink jet recording system is as follows.
The image is formed by ejecting ink supplied to the head from fine nozzles. Nozzle hole diameter 70
It has a cylindrical structure of about μm, and has a heater inside the cylinder that selectively generates heat according to a command from the CPU. When the heater is heated, the dissolved air of the ink in contact with the heater expands and foams, and the ink in the nozzle is pushed out and ejected. Normally, this ink ejection cycle is repeated at a high speed of 5 KHz or more, and fine and high-speed image formation is performed.

In this type of print head, when bubbles in the ink enter the discharge nozzle, an ejection failure occurs. Therefore, it is common to arrange the print head downward with the ink tank holding the ink upward. It is.

However, as described above, the ink jet nozzle has no particular valve mechanism and only keeps the ink from leaking only by the surface tension of the ink with respect to the nozzle hole. If a positive pressure higher than the atmospheric pressure is applied to the ink supplied to the nozzle, the ink leaks from the nozzle.

[0006] Even if the ink is at about atmospheric pressure, if dirt or ink droplets adhere to the nozzle tip, the orifice maintained by the surface tension collapses and the ink leaks out. Conversely, if the negative pressure lower than the atmospheric pressure is too strong for the ink supplied to the nozzle, the ink in the nozzle will be pulled back,
Injection failure will result. Therefore, it is necessary to keep the negative pressure of the ink supplied to the recording head slightly lower than the allowable atmospheric pressure by design.

Therefore, an ink container (tank) for generating a constant negative pressure of ink has been developed. FIG.
(A) and (b) show examples of this type of conventional ink container. In this type of ink container 30, a negative pressure is generated by biasing a spring 32 held in the bag 31 in a direction in which the bag expands, as shown in FIG. As the ink is consumed, the spring 32 held in the bag 31 is further deformed as shown in FIG.

[0008]

In recent years, in this type of ink jet recording apparatus, efforts are being made for high image quality. In order to make the image fine and uniform without increasing the image quality, it is important to reduce the size of the ink droplets ejected from the nozzles and make the size of the ink droplets uniform. As described above, the ink droplet size is determined by the balance between the bubbling force of the heater in the nozzle and the negative pressure of the supplied ink. In other words, it is important to keep the negative pressure of the supplied ink uniform at all times in order to improve the image quality.

However, in the above-described prior art, as the ink is used, the amount of ink in the bag 31 decreases, and the spring 32 held in the bag is gradually crushed and deformed.
The value of the negative pressure applied to the ink is determined by how much the urging force acts on the area on which the urging force of the spring 32 acts. Therefore, with the spring constant of the spring 32, the negative pressure gradually increases in accordance with the amount of the crushed deformation, and there is a problem that the ink droplets cannot be kept small and uniform.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a negative pressure holding mechanism for an ink container for solving these problems.

[0011]

Therefore, in the present invention, the above object is achieved by providing a negative pressure holding mechanism for the ink capacity described in any of the following items (1) to (9). What you want to do.

(1) In a negative pressure holding means of an ink tank for supplying ink to an ink jet recording head and maintaining the ink at a negative pressure in the housing, the ink is communicated with the recording head supply port and a negative pressure container to communicate with outside air. An ink tank having airtightness, a negative pressure container having an upper end fixed so that the upper part of the tank can communicate with the upper part of the tank and the internal air, and capable of changing the inner volume freely, and a weight on the lower surface of the negative pressure container. A negative pressure holding mechanism for the ink container, wherein a capacity of the negative pressure container is increased by the weight of the weight.

(2) A negative pressure holding means of an ink tank for supplying ink to an ink jet recording head and maintaining the ink at a negative pressure in a housing, has an air-tight air-bag capable of changing volume. An ink tank communicating with the recording head supply port and having airtightness between the outside air and the inside of the air bag; and communicating the inside of the air bag with the inside air so as to be vertically expandable and contractible, and that the inner volume is freely variable and the upper end is fixed. A negative pressure container, and a weight on the lower surface of the negative pressure container, wherein the capacity of the negative pressure container is increased by its own weight.

(3) The negative pressure holding mechanism for an ink container as described in (2) above, wherein the air bags in the plurality of ink tanks are connected to one negative pressure container.

(4) There is provided a window or indicator for visually confirming the expansion / contraction state of the negative pressure container, and the expansion / contraction state of the negative pressure container can be visually recognized. The negative pressure holding mechanism of the ink container according to the above.

(5) The apparatus according to any one of (1) and (2), further comprising detecting means for detecting the expansion / contraction state of the negative pressure container, and capable of detecting the expansion / contraction state of the negative pressure container. Negative pressure holding mechanism for the ink container.

(6) The printer according to (1) to (5), further including a carriage for moving the position of the recording head, wherein the recording head and the negative pressure holding mechanism are mounted on the carriage. The negative pressure holding mechanism for the ink container according to any one of the above.

(7) A carriage for moving the position of the recording head, and a cartridge detachable from the carriage, wherein the recording head and the negative pressure holding mechanism are mounted in the cartridge. (1)-
(5) The negative pressure holding mechanism for an ink container according to any of (5).

(8) There is a carriage for moving the position of the recording head, the recording head and the ink tank are arranged on the carriage, the negative pressure container is arranged on the main body, and the ink tank is The negative pressure holding mechanism for an ink container according to any one of the above items (1) to (5), wherein the pressure containers are communicated with each other by a tube.

(9) There is a carriage for moving the position of the recording head, the recording head is disposed on the carriage, the ink tank and the negative pressure container are disposed on the main body, and the carriage is mounted on the carriage. The negative pressure holding mechanism for an ink container according to any one of (1) to (5), wherein the recording head and the ink tank on the main body side communicate with each other by a tube.

[0021]

According to the present invention as described above, the following operations / effects corresponding to the above items (1) to (9) can be obtained.

(1) According to the invention described in the above item (1), when the ink tank has a sufficient amount of ink, the negative pressure container is in an extended state, the ink is consumed, and the ink in the ink tank decreases. Then, since the air corresponding to the reduced amount of ink moves from the inside of the negative pressure container to the ink tank, the negative pressure container gradually contracts. By providing the weight on the lower surface of the negative pressure vessel, the weight of the weight always acts in the direction of increasing the volume of the negative pressure vessel, and generates a negative pressure. Even if the remaining amount of ink decreases, the position of the weight rises, but the force acting in the direction of increasing the area of the negative pressure container is the weight of the weight. Therefore, it is possible to always maintain a constant negative pressure regardless of the amount of remaining ink.

(2) According to the invention described in (2), an air bag is further provided in the ink tank to separate the ink from the air so that the air in the ink tank and the air in the negative pressure container can be moved. Without blocking, it is possible to prevent the ink from flowing into the negative pressure container.

(3) According to the invention described in the above item (3), the negative pressure of a plurality of tanks can be maintained by one negative pressure container, and the space and cost of the negative pressure container can be saved.

(4) According to the invention described in (4), the remaining amount of the ink can be easily confirmed visually.

(5) According to the invention described in (5), the remaining amount of the ink can be electrically detected, and the detection information can be used for control.

(6) According to the invention described in the above (6), the negative pressure generating mechanism is integrated on the carriage, so that there is no need to pass the flow path between the main body and the carriage, so that the configuration is simple.

(7) According to the invention described in the above item (7), the recording head can be easily replaced by integrating the negative pressure generating mechanism in the cartridge.

(8) According to the invention described in (8) above, by disposing the negative pressure container on the main body side, the size of the negative pressure container can be increased, and a large-capacity ink tank can be mounted on the carriage. .

(9) According to the invention described in (9), by disposing the negative pressure container on the main body side, it is possible to supply a large amount of ink while reducing the size of the carriage.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail based on a plurality of embodiments with reference to the drawings.

[0032]

Embodiment (First Embodiment) The first embodiment will be described with reference to FIGS. FIG. 1 is a diagram showing a state where the ink tank of the first embodiment is initially filled with ink, and FIG. 2 is a diagram showing a state where the ink is empty.

A plurality of nozzles for discharging ink are provided, and a recording head 1 for selectively driving nozzles to form an image based on a discharge signal from a recording control unit (not shown) and an ink 2 are stored in the recording head 1. It has an ink tank 3 for supplying ink 2. The bottom area of the ink tank 3 in the illustrated example is 3 cm ²
And the ink capacity is 9 cm ³ .

A communication pipe 5 is connected to an upper part of the ink tank 3, and the communication pipe 5 is connected to an upper part of the negative pressure container 4. The ink tank 3, the communication pipe 5, and the negative pressure container 4 are hermetically sealed so that air communicates with each other and keep airtight with respect to outside air. Therefore, the ink tank 3, the communication pipe 5, and the negative pressure container 4 always have the same pressure, and the amount of air in the ink tank 3, the communication pipe 5, and the negative pressure container 4 is also kept constant.

The negative pressure container 4 is made of a thin material such as polyethylene or rubber, which is a flexible material, and expands and contracts flexibly, so that the inner volume can be changed with the expansion and contraction.
The cross section of the negative pressure container 4 is kept substantially uniform, and the cross sectional area A is 2
cm ² , and the length is expandable and contractible in a range of 0.5 to 5 cm.

In the illustrated example, the negative pressure container 4 has a bellows-like shape having a circular cross-section, so that it can flexibly expand and contract vertically to maintain a uniform cross-sectional area. The negative pressure container 4 is supported at its upper end by the housing of the ink tank 3 in a suspended state, and is guided by the housing of the ink tank 3 so as not to swing laterally.

A weight (weight) 6 is provided at the lower end of the negative pressure container 4, and the weight of the weight 6 is applied in a direction in which the inner volume of the negative pressure container 4 always expands, and a negative pressure is generated in the container. The weight W of the weight 6 in the illustrated example is 20 g, and a negative pressure of −10 g / cm ² is generated in the negative pressure container 4. The inside of the ink tank 3 also has the same negative pressure.

When the ink is discharged from the recording head 1 and the ink is consumed, the amount of the ink 2 decreases as shown in FIG. Since the amount of air in the ink tank 3, the communication pipe 5, and the negative pressure container 4 is constant, the volume of the negative pressure container 4 whose inner volume can be changed decreases by the volume integral of the ink consumption, and the weight 6 is lifted. . For example, if the ink consumption is 8 cm ³ , the volume of the negative pressure container 4 is reduced by 8 cm ³ . Since the sectional area A of the negative pressure vessel is 2 cm ² , the weight 6 rises by 4 cm.

At this time, similarly to the state in which the ink is initially filled, the cross-sectional area A of the negative pressure container 4 is 2 cm ² , and the weight 20 g of the weight 6 acts in the direction in which the negative pressure container 4 expands. As a result, a negative pressure of −10 g / cm ² is generated in the container 4. Thus, regardless of the remaining amount of ink,
The pressure in the ink tank 3 is always kept at a constant negative pressure,
Stable ink droplets can be ejected from the nozzles of the recording head 1.

(Second Embodiment) A second embodiment will be described with reference to FIG.
This will be described with reference to FIG. 3 shows a state diagram in which the ink tank is initially filled with ink, and FIG. 4 shows a state diagram in which the ink is empty.

The structures of the ink tank 3, the communication pipe 5, and the negative pressure container 4 for storing the recording head 1 and the ink 2 and supplying the ink to the recording head 1 are the same as those in the first embodiment.

An air bag 7 is provided in the ink tank 3, and the air bag 7 is connected to the communication tube 5, and the air bag 7, the communication tube 5, and the negative pressure container 4 communicate with each other, and are connected to the outside air. Are sealed to maintain airtightness. In addition, ink tank 3
The airtightness is also maintained between the air bag 7 and the air bag 7. The air bag 7 is formed by welding a material having a thickness of 20 μm, such as polyethylene, in a bag shape, is extremely excellent in flexibility, and requires substantially no external force to inflate and contract the bag. Therefore,
Although the space between the ink tank 3 and the negative pressure container 4 is blocked by the air bag 7, the pressure can be maintained at the same level by the expansion and contraction of the air bag 7. In other words, the ink 2 cannot pass between the ink tank 3 and the pressure container 4, but the pressure can be maintained at the same level between the ink tank 3 and the pressure container 4 as in the first embodiment. .

As in the first embodiment, the ink amount was 9 cm.
^3, and the volume of the air bag can be changed from 0 to 10 cm ³ . In FIG. 3, when the ink is initially filled, if the volume of the air bag 7 is set to 0.5 cm ³ , the pressures in the negative pressure container 4 and the ink tank 3 both become −10 g / cm ² .
As shown in FIG. 4, when the ink is consumed, the bag 7 expands in accordance with the consumed amount of the ink. When the ink is consumed by 8 cm ³ , the air in the negative pressure container 4 enters the air bag 7 and the air bag 7 expands by 8 cm ³ . Also in this case, the pressures in the negative pressure container 4 and the ink tank 3 are both -10 g / cm ² .

Even if the recording device itself is tilted, the air bag 7
Is present, the ink 2 does not move from the ink tank 3 to the negative pressure container 4, and the function of the negative pressure generating mechanism is not impaired.

Thus, regardless of the remaining amount of ink,
The pressure in the ink tank 3 is always kept at a constant negative pressure, the ink 2 can be prevented from moving to the negative pressure container, and stable ink droplets can always be ejected from the nozzles of the recording head 1. .

(Third Embodiment) A third embodiment in which two ink tanks are used will be described with reference to a sectional view shown in FIG. This embodiment is a mechanism for adjusting the pressures of the two ink tanks 3a and 3b by one set of the negative pressure container 4 and the weight 6.

The mechanism for generating a negative pressure for each of the ink tanks 3a and 3b is the same as that of the second embodiment.

The first ink tank 3a and its air bag are
a, the second ink tank is 3b, and its air bag is 7b. Each of the air bags 7a and 7b is connected to the communication pipe 5 so that the negative pressure container 4 and the air can communicate with each other, and airtightness is maintained. If the airtightness of each of the ink tanks 3a and 3b is maintained, the pressure in the negative pressure container 4 and the pressure in each of the ink tanks 3a and 3b become the same as in the second embodiment. Irrespective of this, it is possible to always maintain a constant negative pressure.

Therefore, the negative pressure of the plurality of ink tanks can be kept constant by one set of the negative pressure container 4 and the weight 6.

(Fourth Embodiment) A fourth embodiment will be described with reference to FIGS. FIG. 6 shows a state diagram in which ink is initially filled, and FIG. 7 shows a state diagram in which ink is empty.

In a configuration having a negative pressure generating mechanism similar to the first and second embodiments, an opening 3c and an opening 3c are formed on the side of the housing of the ink tank 3 surrounding the negative pressure container 4. A scale 8 is provided in the vicinity and a mark 6a is provided on the side surface of the weight, and the mark 6a is arranged so as to be recognizable from the opening 3c. As shown in FIG. 6, when the ink is initially charged, the position of the mark 6a is downward, and when the ink in FIG.
The fact that the position a is upward can be visually recognized from the outside, and the user can recognize the remaining amount of ink.

(Fifth Embodiment) A fifth embodiment will be described with reference to FIGS. 8 shows a state diagram in which the ink tank is initially filled with ink, and FIG. 9 shows a state diagram in which the ink is empty.

In the configuration having a negative pressure generating mechanism similar to that of the first and second embodiments, a transmission type photosensor 9 is provided near the negative pressure container 4 and a blocking plate 10 is provided on the side surface of the weight. When the ink is consumed and the weight 6 is completely raised,
The shielding plate 10 is arranged so as to block the light of the transmission type photosensor 9.

With this configuration, it is possible to electrically detect that the ink has run out by the photo sensor 9, and it is possible to notify the circuit for controlling the ejection of the recording head of the ink presence / absence state.

For example, it is possible to prevent the ejection signal of the head in a state where there is no ink, to avoid idle heating, and to avoid the failure of the recording head.

(Sixth Embodiment) FIG. 10 shows a sixth embodiment.
FIG. 10 shows a case where the control circuit controls the movement of the recording head 1 in the main scanning direction, the movement of the recording sheet S in the sub-scanning direction, and the ink discharge of the recording head 1 by a control circuit. 1 is a schematic diagram illustrating an inkjet serial printer that forms an ink image thereon.

The carriage 11 reciprocates in the main scanning direction along the guide shaft 12, and the recording sheet S is conveyed in the sub scanning direction orthogonal to the guide shaft 12. The recording head 1 and the negative pressure generating mechanism are fixed on a carriage 11.

In the figure, a recording head 1, an ink tank 3, a communication tube 5, a negative pressure container 4, and a weight 6 show the negative pressure generating mechanism described in the first and second embodiments. The pressure in the tank 3 is kept constant as shown in the above embodiment, and stable ink can be ejected from the recording head 1 in accordance with the output signal. Since all the negative pressure generating mechanisms are mounted on the carriage 11, a simple device configuration can be realized.

Seventh Embodiment FIG. 11 shows a seventh embodiment.
FIG. 11 is similar to the sixth embodiment.
An inkjet serial printer that controls the movement of the recording head 1 in the main scanning direction, the movement of the recording sheet S in the sub-scanning direction, and the ink discharge of the recording head 1 by a control circuit to form an ink image on the recording sheet S FIG.

The carriage 11 reciprocates in the main scanning direction along the guide shaft 12, and the recording sheet S is conveyed in the sub scanning direction orthogonal to the guide shaft 12.

In the drawing, the recording head 1, the ink tank 3, the communication tube 5, the negative pressure container 4, and the weight 6 are the same as those of the first embodiment and the second embodiment.
FIG. 9 illustrates the negative pressure generating mechanism described in the embodiment, in which the pressure in the ink tank is kept constant as described in the above embodiment, and the recording head 1 supplies stable ink in accordance with an output signal. Can be ejected.

The recording head 1 and the negative pressure generating mechanism are formed in a cartridge 13, and the cartridge 13 is detachably fixed on the carriage 11. When the ink 2 in the ink tank 3 runs out, the entire cartridge 13 can be easily replaced, and the operability is improved.

(Eighth Embodiment) FIG. 12 shows an eighth embodiment.
FIG. 12 is similar to the sixth embodiment,
An inkjet serial printer that controls the movement of the recording head 1 in the main scanning direction, the movement of the recording sheet S in the sub-scanning direction, and the ink discharge of the recording head 1 by a control circuit to form an ink image on the recording sheet S FIG.

The carriage 11 reciprocates in the main scanning direction along the guide shaft 12, and the recording sheet S is conveyed in the sub scanning direction orthogonal to the guide shaft 12.

In the drawing, the recording head 1, the ink tank 3, the communication tube 5, the negative pressure container 4, and the weight 6 are the same as those of the first embodiment and the second embodiment.
The recording head 1 and the ink tank 3 are mounted on the carriage 11, and the negative pressure container 4 and the weight 6 are arranged on the main body. Is extended and connected.

The communication tube 5 is a tube made of a resin such as polyethylene having flexibility, and is bent as the carriage 11 reciprocates. The pressure in the ink tank is kept constant as in the above-described embodiment, and stable ink can be ejected from the recording head 1 in accordance with the output signal.

With the above configuration, the carriage 11 has
Since only the recording head 1 and the ink tank 3 are mounted, the carriage 11 can be downsized if the ink amount is the same as in the seventh embodiment. Or, the embodiment 7
If the size of the carriage is the same, the size of the ink tank and the negative pressure container can be increased.

(Ninth Embodiment) A ninth embodiment will be described with reference to FIG.
FIG. 13 shows the movement of the recording head 1 in the main scanning direction, the movement of the recording sheet S in the sub-scanning direction, and the ink of the recording head 1 as in the sixth embodiment. FIG. 2 is a schematic diagram showing an ink jet serial printer that controls ejection by a control circuit and forms an ink image on a recording sheet S. FIG.

The carriage 11 reciprocates in the main scanning direction along the guide shaft 12, and the recording sheet S is conveyed in the sub scanning direction orthogonal to the guide shaft 12.

As shown in FIG. 14 which is an explanatory view of a main part of FIG. 13, the recording head 1, the ink tank 3, the communication pipe 5, the negative pressure container 4, and the weight 6 are the same as those of the first and second embodiments. The recording head 1 is mounted on a carriage 11, and the ink tank 3, the communication pipe 5, the negative pressure container 4, and the weight 6 are disposed in the main body, and the recording head 1 is provided. 1 and the ink tank 3 are connected by an ink supply pipe 14.

The ink supply tube 14 is a tube made of resin such as polyethylene having flexibility.
Bends with the reciprocating motion of.

The pressure in the ink tank 3 is kept constant as in the above embodiment, and stable ink can be ejected from the recording head 1 in accordance with the output signal.

With the above configuration, the carriage 11
Since only the recording head 1 is mounted, the embodiment 8
The size of the carriage 11 can be further reduced, and the size of the ink tank 2 can be increased.

[0074]

As described above, according to the present invention,
Each of the following effects can be obtained. That is, (1) According to the invention of (1), in a state where the ink is sufficiently in the ink tank, the negative pressure container is in an expanded state,
When ink is consumed and ink in the ink tank decreases,
Since the air corresponding to the reduced amount of ink moves from the inside of the negative pressure container to the ink tank, the negative pressure container gradually contracts. By providing the weight on the lower surface of the negative pressure vessel, the weight of the weight always acts in the direction of increasing the volume of the negative pressure vessel, and generates a negative pressure. Even if the remaining amount of ink decreases, the position of the weight rises, but the force acting in the direction of expanding the volume of the negative pressure container is the weight of the weight. Therefore, it is possible to always maintain a constant negative pressure regardless of the remaining amount of ink.

(2) According to the invention (2),
By providing an air bag in the ink tank and separating the ink from the air, it is possible to prevent the ink from flowing into the negative pressure container without hindering the movement of the air in the ink tank and the negative pressure container.

(3) According to the invention of (3), further,
Negative pressure of a plurality of tanks can be maintained by one negative pressure container, and space and cost of the negative pressure container can be saved.

(4) According to the invention of (4), further,
The remaining amount of ink can be easily checked visually.

(5) According to the invention of (5), further,
The remaining amount of ink can be electrically detected, and the detection information can be used for control.

(6) According to the invention of (6), by integrating the negative pressure generating mechanism on the carriage, it is not necessary to extend the flow path between the main body and the carriage, so that the configuration is simple.

(7) According to the invention of (7), the recording head can be easily replaced by integrating the negative pressure generating mechanism in the cartridge.

(8) According to the invention of (8), by disposing the negative pressure container on the main body side, the size of the negative pressure container can be increased, and a large capacity ink tank can be mounted on the carriage.

(9) According to the invention (9), by disposing the negative pressure container on the main body side, it is possible to supply a large amount of ink while reducing the size of the carriage.

[Brief description of the drawings]

FIG. 1 is a diagram showing an initial filling state of an ink tank according to a first embodiment.

FIG. 2 is an empty state diagram of FIG. 1;

FIG. 3 is a diagram showing an initial filling state of an ink tank.

FIG. 4 is an empty state diagram of FIG. 3;

FIG. 5 is an explanatory sectional view in the case of two ink tanks.

FIG. 6 is a diagram showing an initial filling state of an ink tank.

FIG. 7 is an empty state diagram of the ink of FIG. 6;

FIG. 8 is a diagram showing an initial filling state of an ink tank.

FIG. 9 is an empty state diagram of FIG. 8;

FIG. 10 is a schematic diagram illustrating an inkjet serial printer.

FIG. 11 is a schematic diagram illustrating an inkjet serial printer.

FIG. 12 is a schematic diagram illustrating an inkjet serial printer.

FIG. 13 is a schematic diagram illustrating an inkjet serial printer.

14 is an explanatory view of a main part of FIG. 13;

FIG. 15 is a diagram showing an example of a conventional ink container.

[Explanation of symbols]

 1, 1a, 1b Recording head 2 Ink 3, 3a, 3b Ink tank (ink container) 3c Opening 4 Negative pressure container 5 Communication pipe 6 Weight (weight) 6a Mark 7, 7a, 7b Air bag 8 Scale 9 Photo sensor 10 Shielding plate 11 Carriage 12 Guide shaft 13 Cartridge 14 Ink supply tube S Recording sheet

Claims (9)

[Claims] 1. A negative pressure holding means of an ink tank for supplying ink to an ink jet recording head and keeping the ink at a negative pressure in a housing, wherein the negative pressure holding means communicates with the recording head supply port and a negative pressure container to be airtight. A negative pressure container having an upper end fixed so as to be vertically expandable and contractible and have a variable inner volume, and a weight on the lower surface of the negative pressure container. The negative pressure holding mechanism for the ink container, wherein the capacity of the negative pressure container is increased by the weight of the weight. 2. A negative pressure holding means for an ink tank for supplying ink to an ink jet recording head and maintaining the ink at a negative pressure in a housing, comprising: an air bag having airtightness and a volume changeable inside; An ink tank communicating with the recording head supply port and having airtightness between the outside air and the inside of the air bag, and communicating with the inside of the air bag and the inside air so as to be able to expand and contract in the vertical direction and to have a freely variable upper end and fixed at the upper end; A negative pressure container, and a weight on the lower surface of the negative pressure container, wherein the capacity of the negative pressure container is expanded by the weight of the weight. 3. An air bag in the plurality of ink tanks and one air bag.
3. The negative pressure holding mechanism for an ink container according to claim 2, wherein the negative pressure container is connected to the two negative pressure containers. 4. The ink container according to claim 1, further comprising a window or an indicator for visually confirming the expansion / contraction state of the negative pressure container, wherein the expansion / contraction state of the negative pressure container can be visually recognized. Negative pressure holding mechanism. 5. The ink container according to claim 1, further comprising detection means for detecting the expansion / contraction state of the negative pressure container, and capable of detecting the expansion / contraction state of the negative pressure container. Negative pressure holding mechanism. 6. The printing apparatus according to claim 1, further comprising a carriage for moving a position of the recording head, wherein the recording head and the negative pressure holding mechanism are mounted on the carriage.
6. The negative pressure holding mechanism for an ink container according to any one of claims 1 to 5. 7. A printing apparatus comprising: a carriage for moving a position of the recording head; and a cartridge detachable from the carriage, wherein the recording head and the negative pressure holding mechanism are mounted in the cartridge. 6. The negative pressure holding mechanism for an ink container according to any one of 1 to 5. And a carriage for moving a position of the recording head, the recording head and an ink tank being disposed on the carriage, the negative pressure container being disposed on the main body, and a negative pressure container being disposed on the main body. The negative pressure holding mechanism for an ink container according to any one of claims 1 to 5, wherein the containers are communicated with each other by a tube. 9. A printing apparatus comprising: a carriage for moving a position of the recording head; the recording head disposed on the carriage; the ink tank and the negative pressure container disposed on the main body; The negative pressure holding mechanism for an ink container according to any one of claims 1 to 5, wherein the head and the ink tank on the main body side communicate with each other by a tube.