JP2000006435A - Ink tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the irregularity of negative pressure between a plurality of mutual storage chambers without being affected by the irregularity of consumption between the inks in the storage chambers. SOLUTION: Freely expansible ink tanks 24Bk, 24C, 24M, 24Y are placed on a bottom part movable support member 26 and, when respective inks are consumed in this state by the urging force of a coil spring 28, the ink tanks 24Bk-24Y are contracted corresponding to the total ink consumption quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink tank capable of uniformly maintaining the pressure in a plurality of storage chambers for storing ink supplied to a recording unit which performs a recording operation by discharging ink on a recording surface of a recording medium. About.

[0002]

2. Description of the Related Art In an ink jet recording apparatus, a recording section which performs a recording operation by discharging ink onto a recording surface of a recording medium is connected to an ink tank in which ink is stored. The ink tanks are provided independently for each color ink, for example, as shown in FIG. The ink tank is an ink storage chamber 1 for storing ink.
And a cover member 4 that covers an opening end of the ink storage chamber 14 of the ink tank case main body 2 as main components.

The ink storage chamber 14 of the ink tank case main body 2 is formed by a housing film member 6 having a bottom and surrounding the inner wall surface of the ink tank case main body 2 and an inner wall of the cover member 4. As a result, the space in the ink tank case main body 2 is separated from the ink storage chamber 14
And the atmosphere communication chamber 16. The inside of the ink storage chamber 14 is filled with a predetermined amount of ink. The upper end of the housing film member 6 made of a flexible material is held between the engaging portion 4 d of the cover member 4 and the inner wall surface of the ink tank case body 2.

The outer surface of the bottom of the housing film member 6 is supported by a bottom movable support member 10 disposed in an atmosphere communication chamber 16 which communicates with the atmosphere through a through hole 2a provided in the bottom of the ink tank case body 2. I have. The bottom movable support member 10 is provided with a coil spring 12 disposed between the lower surface thereof and an opposed bottom inside the ink tank case body 2.
Supported by As a result, the bottom movable support member 10 is urged by the urging force of the coil spring 12 in the direction in which the volume in the ink storage chamber 14 decreases, so that the bottom of the containing film member 6 is raised in accordance with the consumption of ink. Will be done.

[0005] The cover member 4 has an inlet 4b. An injection needle 18 connected to the other end of the ink supply path, one end of which is connected to a recording unit (not shown), is inserted through the rubber septum member 8 into the injection port 4b. Inlet 4
A rubber septum member 8 is press-fitted into b. The cover member 4 has an atmosphere communication hole 4a.

[0006] Since the ink tank is disposed at a position lower than the position of the ink discharge port forming surface of the recording section by a predetermined amount, the pressure in the ink storage chamber 14 is maintained at a negative pressure corresponding to the level difference. It is. The value of the negative pressure affects the ink refill time after the printing operation of the printing unit, and thus affects, for example, the ink ejection amount of the printing unit.

[0007]

However, when a plurality of ink tanks are provided for each of the recording heads of the recording section, the amount of ink consumed in each of the ink tanks, The height difference between the liquid level in each ink tank and the position of each ink ejection port forming surface of the recording unit varies due to the variation in the urging force, and the negative pressure in the ink tank may vary.

In addition, if the estimated ink consumption in each ink tank is taken into consideration and the internal volumes of the respective ink tanks are uniformly equalized according to the estimated maximum consumption, this leads to an increase in the size of the apparatus. .

In view of the above problems, the present invention maintains the pressure in a plurality of storage chambers for storing ink to be supplied to a recording unit that performs a recording operation by discharging ink on a recording surface of a recording medium. An ink tank capable of avoiding variations in negative pressure among the respective storage chambers without being affected by variations in the consumption of ink in the plurality of storage chambers, and An object of the present invention is to provide an ink tank that can increase ink consumption efficiency.

[0010]

In order to achieve the above-mentioned object, an ink tank according to the present invention comprises a plurality of ink discharge port forming surfaces of a recording unit which performs a recording operation by discharging ink onto a recording surface of a recording medium. A plurality of storage chambers for accommodating ink forming a liquid surface at a position relatively lower than the position corresponding to each ink ejection port forming surface portion and supplying ink to the recording portion; Biasing means for biasing the plurality of storage chambers in a direction in which the plurality of storage chambers contract in a relationship in which the total consumption amount and the displacement amount of the ink in the plurality of storage chambers formed adjacent to each other are proportional to each other. Be composed.

[0011]

FIG. 2 schematically shows a first embodiment of an ink tank according to the present invention, together with a recording section to which the ink tank is applied.

In FIG. 2, a recording section 20 is disposed above a recording surface of a sheet Pa as a recording medium conveyed in a conveying direction indicated by an arrow F by conveying means (not shown).

The recording section 20 includes four recording heads 20B.
k, 20C, 20M, and 20Y. Recording heads 20Bk, 20C, 20M, and 2
0Y are sequentially arranged along the transport direction indicated by the arrow F. The recording heads 20Bk to 20Y
Each has an ink ejection port forming surface on which a plurality of ink ejection ports are formed in a direction substantially orthogonal to the transport direction indicated by the arrow F. Further, the ink discharge port forming surface is formed to face the recording surface of the paper Pa. Each of the recording heads 20Bk to 20Y has a known structure of, for example, a bubble jet type. The recording operation of the recording heads 20Bk to 20Y is controlled based on a drive control pulse signal from a control unit (not shown).

In the common liquid chambers of the recording heads 20Bk to 20Y, ink supply tubes 34Bk, 34C,
One ends of 34M and 34Y are connected. Injection needles 36 are connected to the other ends of the ink supply tubes 34Bk to 34Y, respectively. Each injection needle 36 is pierced into each rubber septum member 32 of the ink tank case 22 described later.

The ink supply tubes 34Bk to 34Y are
By the injection needle holding plate 40, air communication tubes 38Bk, 38C, 38M, and 3
8Y and is integrally held adjacent thereto. An ink supply pump unit 42 is provided between one end and the other end of the ink supply tubes 34Bk to 34Y.

The ink supply pump unit 42 selectively supplies a predetermined amount of each ink to the recording heads 20Bk to 20Y through the ink supply tubes 34Bk to 34Y before the recording operation of the recording heads 20Bk to 20Y starts. The ink supply pump unit 42 is selectively driven at a predetermined timing by the control unit. Then, after the ink supply pump unit 42 is driven, the recording heads 20Bk to 20Y and the ink tanks 24Bk, 24C,
4M and 24Y are in communication with each other, and each ink is filled in the ink supply tubes 34Bk to 34Y.

As shown in FIG. 1, the ink tank case 22 is partitioned by a bottom movable support member 26 to form ink tanks 24Bk, 24C, 24 as ink storage chambers.
M and 24Y are accommodated, and a spring accommodation room 30 formed below the accommodation room is provided.

The ink tanks 24Bk and 24 in the accommodation chamber
C, 24M, and 24Y are each formed in a bag shape from a stretchable material, for example, a rubber material.

The ink tanks 24Bk, 24C, 24M,
And 24Y are provided adjacent to each other in a line. Ink tanks 24Bk, 24C, 24
M and 24Y have the same predetermined amounts of black ink, cyan ink, magenta ink,
And, yellow ink is filled.

The ink tanks 24Bk, 24C, 24M,
The upper opening end of 24Y is engaged with a cylindrical portion 22P provided inside the upper portion of the ink tank case 22, respectively. At positions on the upper part of the ink tank case 22 facing the respective cylindrical portions 22P,
Connecting parts 22BIa, 22BIi, connecting parts 22CIa, 2
2CIi, connection parts 22MIa, 22MIi, connection part 22
YIa and 22YIi are provided. Each connection part 22B
Rubber septum members 32 are press-fitted into Ia to 22YIi.

Inside each of the cylindrical portions 22P, on the upper portion of the ink tank case 22, each of the connecting portions 22BIa to 22YI
a, one end of each of the air communication passage AR formed therein and one end of the ink passage IR into which the injection needle 36 is inserted is opened inside each of the connection portions 22BIi to 22YIi.

The bottoms of the ink tanks 24Bk to 24Y are
It is mounted on the same upper surface of the bottom movable support member 26 which is a plate-like member.

The bottom movable support member 26 is slidably in contact with the inner wall surface of the ink tank case 22 so as to be vertically movable.

A coil spring 28 for urging the ink tanks 24Bk to 24Y in a contracting direction is provided between the lower surface of the movable bottom member 26 in the spring chamber 30 and the inner surface of the bottom of the ink tank case 22. I have. Further, the spring accommodating chamber 30 communicates with the outside through a through hole 22 a provided in the bottom of the ink tank case 22.

The spring characteristics of the coil spring 28 are as follows:
It is set based on the reasons described below.

FIG. 4 schematically shows a basic configuration of a recording section and an ink tank to which an example of the ink tank according to the present invention is applied. When an ink tank 54 having an atmosphere communication hole 54a communicating with the atmosphere is connected via an ink supply path 52, the water head between the ink discharge port forming surface of the recording head 50 and the ink level in the ink tank 54
When H is present, the state of the meniscus of the ink IK on the ink ejection port forming surface of the recording head 50 is shown.

In FIG. 4, a heater 50h as an electrothermal converter for discharging ink from each of the discharge ports 50n by a film boiling phenomenon is provided in each of the ink flow paths leading to each of the discharge ports 50n of the recording head 50. I have.

Since a negative pressure is generated in the recording head 50 and the ink supply path 52 according to the value obtained by multiplying the ink density and the water head H, the ink is discharged from each of the ejection ports 50.
n, a meniscus of ink is formed,
In addition, the successive ink supply is repeated. At that time, since the water head H changes with the consumption of the ink IK, the value of the negative pressure changes.

Therefore, in setting the spring characteristics of the coil spring 28 so that the value of the negative pressure does not change with the consumption of the ink IK, the load P required to deform the coil spring 28 having the spring constant K is set. Is (1)
It is shown by the formula.

P = -KL + G (1) However, the spring constant K of the coil spring 28 is such that the total ink consumption weight V in the ink tanks 24Bk to 24Y is proportional to the predetermined movement amount L of the bottom movable support member 26. (K = V / L), and the initial load G in the free length is the weight of the bottom movable support member 26 and the weight of the ink tanks 24Bk to 24Y in the initial state (including the ink weight). ) And the combined weight.

With this configuration, when the recording operation is performed by the recording unit 20 and the respective inks are consumed, the ink tanks 24Bk to 24Y are totally moved by the urging force of the coil spring 28 as shown in FIG. It is contracted in accordance with the amount of ink consumption. At that time, each ink tank 24
Since Bk to 24Y are adjacent to each other, each of the ink tanks 24Bk to 24Y is deformed complementarily by an amount corresponding to the difference between the consumption amounts. As a result, the liquid level in each of the ink tanks 24Bk to 24Y is made uniform. Also, by the urging force of the coil spring 28,
A change in the head of each ink is also suppressed so that the heads are the same irrespective of the amount of consumption of each ink.

The head H between the ink discharge port forming surface of the recording head 50 and the ink level in the ink tank 54 is
Due to the arrangement in the apparatus, if the distance is not within a predetermined range corresponding to the recording head 50, the coil spring 28
May be adjusted such that a negative pressure corresponding to the water head H within the predetermined range is formed.

FIG. 5 shows a second embodiment of the ink tank according to the present invention.
2 shows a main part of the embodiment.

In FIG. 5, in the example shown in FIG.
The acting direction of the urging force of the coil spring 28 is set to a direction substantially orthogonal to the arrangement direction of the ink tanks 24Bk to 24Y. Instead, the acting direction of the urging force of the coil spring 64 is changed to each of the ink tanks 60Bk and 60C. , 60
M and the direction along the arrangement direction of 60Y.
5, the same components as those in the example shown in FIG. 1 are denoted by the same reference numerals, and the description thereof will not be repeated.

In FIG. 5, the ink tank case 56
Is provided with an accommodation chamber for accommodating the ink tanks 60Bk, 60C, 60M, and 60Y as the ink storage chambers which are pressed by the urging force of the coil spring 64 via the movable pressing member 62.

The storage chamber communicates with the outside through a through hole 56 a provided in a side wall of the ink tank case 56.

The ink tanks 60Bk and 60B in the accommodation chamber
C, 60M, and 60Y are each formed in a bag shape from a stretchable material, for example, a rubber material.

The ink tanks 60Bk, 60C, 60M,
And 60Y are provided adjacent to each other in a line. Ink tanks 60Bk, 60C, 60
M and the bottom of 60Y are ink tank case 56
Abuts against the lower inner wall surface of the ink tank 60B.
One side surface of k is in contact with the inner wall surface of the side of the ink tank case 56. Further, the ink tank 60Y
Is in contact with the movable pressing member 62.

Thus, the ink tanks 60Bk, 60B
C, 60M and 60Y are ink tank cases 5
6 is held between the inner wall surface of the side part 6 and the movable pressing member 62 at a predetermined pressure. In addition, each ink tank 60
The side surfaces of Bk to 60Y are evenly pressed with a predetermined pressure.

The ink tanks 60Bk, 60C, 60M,
And 60Y are filled with the same predetermined amounts of black ink, cyan ink, magenta ink, and yellow ink, respectively.

The ink tanks 60Bk, 60C, 60M,
The upper opening end of 60Y is engaged with a cylindrical portion 56P provided inside the upper portion of the ink tank case 56, respectively. At positions on the upper part of the ink tank case 56 facing the respective cylindrical portions 56P,
Connecting portions 56BIa, 56BIi, connecting portions 56CIa, 5
6CIi, connection units 56MIa, 56MIi, connection unit 56
YIa and 56YIi are provided. Each connection section 56B
Rubber septum members 58 are press-fitted into Ia to 56YIi.

In FIG. 5, both ends of the movable pressing member 62 are in sliding contact with the inner wall surface of the ink tank case 56, and are supported so as to be able to reciprocate in the left-right direction.

A coil spring 64 for urging the ink tanks 60Bk to 60Y in a contracting direction is provided between one end surface of the movable pressing member 62 and the opposing inner surfaces inside the ink tank case 56. . The spring characteristics of the coil spring 64 are the same as those of the above-described example.
Is set so that the value of the negative pressure does not change with the consumption of. The spring constant K of the coil spring 64 is equal to the ink IK
So that the value of the negative pressure in each of the ink tanks 60Bk to 60Y does not change with consumption of the ink tanks 60Bk to 60Y.
The value is such that the total ink consumption weight V in 0Y is proportional to the predetermined moving amount L of the movable pressing member 62.

With this configuration, when the recording operation is performed by the recording unit 20 and the respective inks are consumed, the ink tanks 60Bk to 60Y are entirely moved by the urging force of the coil spring 64 via the movable pressing member 62. Pressing is performed according to the amount of ink consumption. At this time, since the ink tanks 60Bk to 60Y are adjacent to each other, the ink tanks 60Bk to 60Y are deformed complementarily by an amount corresponding to the difference in consumption between the ink tanks. That is, among the ink tanks 60Bk to 60Y, the ink tank that consumes a relatively large amount is more greatly deformed than the other ink tanks. Thereby, each of the ink tanks 60Bk to 60Y
The liquid level in the ink tank 60B is made uniform.
Variation of the negative pressure in k to 60Y is suppressed.

FIG. 7 shows a third embodiment of the ink tank according to the present invention.
2 shows a main part of the embodiment.

In the example shown in FIG. 1, the bottom movable support member 26 and the coil spring 28 are provided in the ink tank case 22. However, in the example shown in FIG. 7, the bottom movable support member 26 and the coil spring 28 are not provided in the ink tank 70.

This is because the ink tank case 22 is set in advance to the recording head 50 so that the head H between the ink discharge port forming surface of the recording head 50 and the ink level in the ink tank case 22 is within a predetermined range. Placed against
For example, the negative pressure inside the recording head 50 is 20 to 70
(Mmaq).

As shown in FIG. 7, the ink tank case 70 has a storage chamber for storing ink tanks 72Bk, 72C, 72M, and 72Y as ink storage chambers inside the ink tank case. The storage chamber communicates with the outside through a through hole 70 a provided in a side wall of the ink tank case 70.

The ink tanks 72Bk, 72 in the storage chamber
C, 72M, and 72Y are each formed in a bag shape from a stretchable material, for example, a rubber material. The maximum internal volumes of the ink tanks 72Bk to 72Y are substantially the same. FIG. 7 shows a state in which each ink is filled with the same filling amount. That is, the ink tanks 72Bk to 72Y are filled with the same filling amounts of black ink, cyan ink, magenta ink, and yellow ink, respectively.

The ink tanks 72Bk to 72Y are provided adjacent to each other in a line. Each ink tank 72
The upper open ends of Bk to 72Y are connected to the ink tank case 7.
0 is engaged with a cylindrical portion 70P provided inside the upper portion of the “0”. Connection portions 70B, 70C, 70M, and 70Y are provided at positions on the upper portion of the ink tank case 70 that face the respective cylindrical portions 70P. A rubber septum member 74 is press-fitted into each of the connection portions 70B to 70Y.

The inside of each cylindrical portion 70P, each connecting portion 70B
Inside 70Y, an ink passage IR is formed at a position to be an upper portion of the ink tank case 70, respectively. Each of the injection needles 36 of each of the ink supply tubes 34Bk to 34Y is inserted into the ink passage IR via a rubber septum member 74. In the example shown in FIG. 8, a case is shown where the filling amount of the black ink, which consumes a relatively large amount of ink, is made larger than the filling amounts of the other inks. The filling amounts of the other inks, that is, the cyan ink, the magenta ink, and the yellow ink are the same.

Accordingly, the black ink is emptied earlier than when the same amount of each ink is filled,
On the other hand, a situation in which other ink remains in a predetermined amount or more is avoided. As a result, it is less likely that all the ink tanks will be replaced while ink other than the black ink remains, thereby increasing the ink consumption efficiency.

FIG. 9 shows a fourth embodiment of the ink tank according to the present invention.
2 shows a main part of the embodiment.

In the example shown in FIG. 9, the maximum inner volume of the ink tank 82Bk in which the black ink, which consumes a relatively large amount of ink, is filled in advance is set to the ink filled with other inks. It is set larger than the maximum internal volume of the tanks 82C to 82Y. The maximum internal volumes of the other ink tanks 82C to 82Y are the same.

As shown in FIG. 9, the ink tank case 80 has a housing chamber for housing the ink tanks 82Bk, 82C, 82M, and 82Y as ink storage chambers inside. The storage chamber communicates with the outside through a through hole 80 a provided in a side wall of the ink tank case 80.

Similarly to the above-described example, each of the ink tanks 82Bk to 82Y in the storage chamber is formed in a bag shape from an elastic material, for example, a rubber material. The ink tanks 82Bk to 82Y are filled with black ink, cyan ink, magenta ink, and yellow ink, respectively.

The ink tanks 82Bk to 82Y are provided adjacent to each other in a line. Each ink tank 82
Bk to 82Y are open end portions of the ink tank case 8
0 are respectively engaged with the cylindrical portions 80P provided inside the upper portion of the “0”. Connection portions 80B, 80C, 80M, and 80Y are provided at positions on the upper portion of the ink tank case 80 that face the respective cylindrical portions 80P. A rubber septum member 84 is press-fitted into each of the connection portions 80B to 80Y.

The inside of each cylindrical portion 80P, each connecting portion 80B
Inside 80Y, an ink passage IR is formed in the upper part of the ink tank case 80, respectively. The respective injection needles 36 of the respective ink supply tubes 34Bk to 34Y are inserted into the ink passages IR via rubber septum members 84, respectively. The ink tanks 82Bk to 82Y
Is maintained at such a position that substantially the same water head can be obtained even when there is a difference in the amount of consumption of each ink.

[0059]

As is apparent from the above description, according to the ink tank of the present invention, the plurality of storage chambers are located at positions relatively lower than the positions of the plurality of ink discharge port forming surfaces of the recording section. The inks forming the liquid surface are respectively accommodated corresponding to the respective ink ejection port forming surface portions and the ink is supplied to the recording portion, and the urging means are contractably formed adjacent to each other while supplying the ink to the recording portion. Urges multiple storage chambers in the direction in which the multiple storage chambers contract in a proportional relationship between the total amount of ink consumption and the amount of displacement in the storage chambers, thus affecting variations in ink consumption and the like in the multiple storage chambers. Without being
Variations in negative pressure between the storage chambers can be avoided.

In addition, the plurality of storage chambers having the same maximum internal volume are filled with a predetermined amount of ink in accordance with the estimated total consumption of each ink, so that the ink consumption efficiency of each ink is improved. Can be.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration diagram showing an example of an ink tank according to the present invention, together with a recording unit to which the ink tank is applied.

FIG. 3 is a cross-sectional view for explaining the operation in the example shown in FIG. 1;

FIG. 4 is a diagram provided for explanation of the operation in the example shown in FIG. 1;

FIG. 5 is a sectional view showing a second embodiment of the ink tank according to the present invention.

FIG. 6 is a cross-sectional view illustrating a configuration of a conventional ink tank.

FIG. 7 is a sectional view showing a third embodiment of the ink tank according to the present invention.

8 is a cross-sectional view showing a case where the filling amount is different in the example shown in FIG. 7;

FIG. 9 is a sectional view showing a fourth embodiment of the ink tank according to the present invention.

[Explanation of symbols]

20 recording unit 24Bk, 24C, 24M, 24Y, 60Bk, 60
C, 60M, 60Y72Bk, 72C, 72M, 72
Y, 82Bk, 82C, 82M, 82Y Ink tank 26 Bottom movable support member 28, 64 Coil spring 62 Movable pressing member

Claims (14)

[Claims] An ink that forms a liquid surface at a position relatively lower than a position of a plurality of ink discharge port forming surface portions of a recording unit that performs a recording operation by discharging ink on a recording surface of a recording medium is provided.
A plurality of storage chambers, each of which is stored corresponding to each ink ejection port forming surface and supplies the recording section with the ink, and the total consumption of ink in the plurality of storage chambers formed adjacent to each other in a contractible manner. An urging means for urging the plurality of storage chambers in a direction in which the plurality of storage chambers contract in a proportional relationship between the amount and the displacement amount. 2. The ink tank according to claim 1, wherein the plurality of storage chambers are contracted complementarily by being urged by the urging means. 3. The ink tank according to claim 1, wherein the plurality of storage chambers individually store different types of ink. 4. The ink tank according to claim 1, wherein each of the plurality of storage chambers is formed of a stretchable material into a bag shape. 5. A support plate is further provided between the urging means and a bottom of the plurality of storage chambers, the support plate supporting the bottoms of the plurality of storage chambers on the same plane. Item 7. An ink tank according to Item 1. 6. A supporting plate disposed between the urging means and a side wall of at least one of the plurality of storage chambers, the supporting plate being provided in contact with the side wall of the storage chamber. The ink tank according to claim 1, wherein: 7. The ink tank according to claim 5, wherein said urging means is an elastic member having a spring constant which is a ratio of a total consumption amount of the ink and a movement amount of the support plate. 8. The ink tank according to claim 1, wherein each of the plurality of storage chambers communicates with the atmosphere. 9. The ink tank according to claim 1, wherein the recording section has an electrothermal converter that heats the ink and discharges the ink from an ink discharge port forming surface. 10. An ink supply means for selectively supplying ink in the plurality of storage chambers to the recording section before the recording operation of the recording section is provided between the recording section and the storage chamber. The ink tank according to claim 1, wherein: 11. A printing apparatus for performing a printing operation by discharging ink on a printing surface of a printing medium at a predetermined position which is relatively lower than a position of a plurality of ink discharge port forming surface parts and a predetermined negative inside the printing part. A plurality of storage chambers for storing ink forming a liquid surface so as to have a pressure, respectively, corresponding to each ink ejection port forming surface part, and supplying the ink to the recording part; and An ink tank, comprising: a storage chamber configured to be adjacently stored, wherein each of the plurality of storage chambers is formed to be expandable and contractible. 12. The storage chamber according to claim 11, wherein the plurality of storage chambers having the same maximum internal volume are filled with a predetermined amount of ink in accordance with the estimated total consumption of each ink. Ink tank. 13. A method according to claim 11, wherein said plurality of storage chambers having different maximum internal volumes are filled with a predetermined amount of ink in accordance with an estimated total consumption amount of each ink. Ink tank. 14. The apparatus according to claim 11, wherein a maximum ink filling amount of at least one of the plurality of storage chambers is larger than a maximum ink filling amount of the other storage chambers. Ink tank.