Ink supply device, ink-jet recording device, and method of supplying ink

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ink supply device that supplies ink into a sub ink tank of a recording head unit, an ink-jet recording device having the ink supply device, and a method of supplying ink.

2. Description of the Related Art

In the ink-jet recording device that ejects ink drops on a recording medium such as a paper from recording heads on the basis of image information and records the image, there is such a configuration that mounts the sub ink tanks corresponding to each of the recording heads on a carriage to make the recording heads scan, in which there are various types of proposals as to the supply of ink into the sub ink tanks.

For example, Japanese Published Unexamined Patent Application No. Hei 6-238911 discloses an ink-jet printer as shown in

FIG. 18

, in which an ink tank

314

is disposed on one end of the shifting range of a recording head

312

. The ink tank

314

has an ink supply outlet

318

formed at a position corresponding to an ink supply inlet

316

of the recording head

312

, and has a bellow portion

320

formed on the middle thereof. And, as the recording head

312

returns to the home position, the ink supply inlet

316

of the recording head

312

is connected with the ink supply outlet

318

of the ink tank

314

, and the recording head

312

is pressed to the ink tank

314

by a drive force of a drive motor not illustrated; thus, the bellow portion

320

of the ink tank

314

shrinks by this pressing force. Accordingly, the content volume of the ink tank

314

varies, and the ink inside the ink tank

314

flows into a common liquid chamber by way of the ink supply outlet

318

and the ink supply inlet

316

. The ink tank

314

that once shrank recovers the original volume by the recording head

312

shifting and releasing the pressure, and by a self-restoring force of the bellow portion

320

. AT this moment, a check valve

322

provided with the ink tank

314

opens, and the air equivalent to the volume of ink supplied into the recording head

312

flows into the ink tank

314

from an air intake

324

.

However, in the construction in which the supply of ink is carried out by such pressurization, the supply of ink can take a comparably long time in some cases, which sometime lowers the efficiency of the ink supply.

In contrast to this, as shown in FIG.

19

and

FIG. 20

, the Japanese Published Unexamined Patent Application No. Hei 11-240180 discloses an ink-jet recording device that includes a first tank

354

provided with a recording head

352

and a second tank

356

to supply ink into the first tank

354

. A switching hole

362

on a partition wall

360

that separates an ink chamber

358

of the first tank

354

from the recording head

352

can be opened and closed by a check valve

364

; and as a differential pressure is produced, the switching hole

362

is to open. Supply of ink into the ink chamber

358

needs to couple a suction hole

366

with a suction cap

368

, and thereafter drive a supply pump

370

, thus decompressing the first tank

354

. Next, a rubber seal

372

is made to advance by driving a reversible motor, and a needle

374

projected on the first tank

354

is inserted into the rubber seal

372

, whereby the first tank

354

is connected with the second tank

356

. Since the first tank

354

is in decompression, the ink is supplied from the second tank

356

into the first tank

354

by way of a tube

376

.

However, in this construction, since the first tank

354

is not made to communicate with the atmosphere, the check valve

364

is required in order to prevent an ink leakage or air suction through a nozzle

378

, due to a variation of the inner pressure, thereby making the structure complicated.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above circumstances, and provides an ink supply device that permits supply of ink securely with a simple construction into a sub ink tank having an air communication hole, a method of supplying ink, and an ink-jet recording device provided with the ink supply device.

According to one aspect of the invention, the ink supply device possesses an ink supply unit provided in correspondence with a recording head unit including a recording head that ejects ink drops onto a recording medium on the basis of image information, and a sub ink tank provided with an air communication hole, storing the ink supplied to the recording head, which implements ink supply by a pressure reduction part reducing a pressure inside the sub ink tank; and a sealing part that at least permits sealing of the air communication hole while the ink supply unit is reducing the pressure inside the sub ink tank.

According to this invention, the sub ink tank that the ink is supplied into is provided with the air communication hole. This air communication hole softens a surge pressure variation inside the sub ink tank, accompanied with ejection's of ink and/or environmental changes, and so forth, and prevents an unexpected ink leakage from the sub ink tank and a mixture of air (air suction from an ink discharging nozzle of the recording head, and creation of air bubbles inside the sub ink tank). Thus, the recording head maintains an optimum state for discharge of ink drops.

Also, since the ink supply device has the sealing part, at least the device is able to seal the air communication hole of the sub ink tank, while the ink supply unit is reducing the pressure inside the sub ink tank. In the sealing state, as the pressure reduction part reduces the pressure inside the sub ink tank, the air does not flow unexpectedly into the sub ink tank, and the ink flows securely into the sub ink tank, thus achieving a smooth ink supply.

In addition, the ink supply is carried out not by the pressurization but by the decompression inside the sub ink tank; and the ink supply can securely be carried out in a shorter time.

According to another aspect of the invention, the ink supply device further includes a displacement mechanism that displaces the ink supply unit in relation to the sub ink tank between a non-supply position where the ink is not supplied and a supply position where the ink is supplied, wherein the sealing part is provided with the ink supply unit, and it carries out sealing of the air communication hole, based on a displacement from the non-supply position to the supply position by the displacement mechanism.

That is, the ink supply unit is displaced by the displacement mechanism from the non-supply position to the supply position in relation to the sub ink tank. The ink supply unit is designed to supply ink into the sub ink tank at the supply position, where the ink is supplied into the sub ink tank.

As the ink supply unit displaces from the non-supply position to the supply position, by this displacement, the sealing part seals the air communication hole. In this manner, the utilization of the displacement of the ink supply unit simplifies the construction, and also secures the sealing of the air communication hole, interlocking with the ink supply operation into the sub ink tank.

Further, the sealing part is provided integrally with the ink supply unit.

Thereby, the ink supply device reduces the number of components, simplifies its construction to diminish the size, and reduces the manufacturing cost.

According to another aspect of the invention, the ink supply unit is provided with an air suction member and an ink supply member that are connected to the sub ink tank, and the sealing part is made to seal the air communication hole, after the air suction member and the ink supply member are connected to the sub ink tank.

Therefore, after the air suction member and the ink supply member are connected to the sub ink tank, the sealing part seals the air communication hole. In this state, as the air suction member sucks the air inside the sub ink tank, the ink flows into the sub ink tank from the ink supply member, resulting in supplying ink.

Now, in this series of operation, if the construction is such that the sealing part seals the air communication hole first, and then the air suction member and the ink supply member are connected to the sub ink tank, there will be apprehensions that a slight variation of pressure created during connection will not be absorbed, because the air communication hole is already sealed. In contract to this, in this invention, since the air suction member and the ink supply member are connected to the sub ink tank first, and then, the sealing part seals the air communication hole, a slight variation of pressure created during connection will be absorbed by the air communication hole that is not sealed.

According to another aspect of the invention, the ink supply member is provided with a valve mechanism.

This provision of the valve mechanism blocks up the ink supply member except during the ink supply, which precludes unexpected drying of ink, mixture of foreign matters into the ink, and so forth.

According to another aspect of the invention, a plural number of ink supply units are provided in correspondence with the plural recording head units, and the displacement mechanism displaces a specific one of the ink supply units and the sealing parts in relation to the corresponding specific one of the recording head units independently from the other ink supply units and sealing parts.

Since the plural ink supply units are provided in correspondence with the plural recording head units, for example, an ink-jet recording device capable of color image recording is able to supply ink into the sub ink tank of the recording head unit individually for each color.

According to another aspect of the invention, the pressure reduction part includes a suction pump.

The suction by the suction pump secures decompression inside the recording head unit in a short time.

According to another aspect of the invention, the ink-jet recording device includes any one of the foregoing ink supply devices, and a recording head unit including a sub ink tank into which the ink supply device supplies ink, provided with an air communication hole, and a recording head that ejects the ink supplied from the sub ink tank onto a recording medium on the basis of image information as ink drops.

In this ink-jet recording device, the ink supplied from the ink supply device into the sub ink tank of the recording head unit is ejected as ink drops onto a recording medium by the recording head, thereby forming an image on the recording medium. The sub ink tank is provided with the air communication hole, which eases a pressure variation due to ejection of ink and environmental changes, and so forth. Thereby, an unexpected ink leakage from the sub ink tank and a mixture of air into the sub ink tank can be prevented, and the recording head maintains an optimum state for discharge of ink drops.

And, since this ink-jet recording device includes any one of the foregoing ink supply devices, it is able to seal the air communication hole of the sub ink tank while supplying ink. In the sealing state, the decompression inside the sub ink tank by the pressure reduction part will preclude an unexpected flow of air into the sub ink tank through the air communication hole; and accordingly, the ink securely flows into the sub ink tank. Thus, the ink is supplied by means of the decompression inside the sub ink tank, not by the pressurization, and a secure ink supply can be achieved in a shorter time.

According to another aspect of the invention, it is preferable that both a supplying connection portion to which the ink supply member is connected and an sucking connection portion to which the air suction member is connected, in the sub ink tank, include a valve mechanism.

Therefore, the valve mechanism is able to block up the supplying connection portion and the sucking connection portion, except while supplying ink into the sub ink tank, whereby unexpected evaporation of ink and leakage of ink and so forth can be prevented.

According to another aspect of the invention, the method of supplying ink into a sub ink tank provided with an air communication hole, in which the ink supplied to a recording head is stored includes a connection step of connecting an air suction member and an ink supply member to the sub ink tank, the air suction member capable of sucking air from the sub ink tank and the ink supply member capable of supplying the ink into the sub ink tank; a sealing step of sealing the air communication hole by a sealing part, after the connection step; and an suction step of sucking the air from the sub ink tank by the air suction member, after the sealing step.

That is, at the connection step, after the air suction member and the ink supply member are connected to the sub ink tank, at the sealing step, the sealing part seals the air communication hole. Therefore, if there is a slight variation of pressure created during connection, the variation of pressure will be absorbed by the air communication hole that is not sealed.

Thereafter, at the suction step, the air suction member sucks the air from the sub ink tank. Thereby, the ink flows into the sub ink tank through the ink supply member. Since the sealing part seals the air communication hole, the ink can be supplied securely into the sub ink tank in a shorter time.

In addition, the sub ink tank into which the ink is supplied has the air communication hole, which softens pressure variations inside the sub ink tank resulting from the discharges of ink and environmental changes and so forth. Thereby, an unexpected ink leakage from the sub ink tank and a mixture of air into the sub ink tank can be prevented, and the recording head maintains an optimum state for discharge of ink drops.

According to another aspect of the invention, the method of supplying ink further includes a sealing release step of releasing the sealing of the air communication hole by the sealing part, after the suction step; and a disconnection step of disconnecting the air suction member and the ink supply member from the sub ink tank, after the sealing release step.

Thus, after the ink supply is completed, first the sealing of the air communication hole is released at the sealing release step, and next at the disconnection step, the air suction member and the ink supply member are disconnected from the sub ink tank. Therefore, if there occurs a slight pressure variation during disconnection, this pressure variation will be absorbed, because the air communication hole is already opened (not sealed) at this moment.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will be described in detail based on the followings, wherein:

FIG. 1

is a perspective view illustrating a recording head carriage and its neighboring area of an ink-jet recording device provided with an ink supply device relating to one embodiment of the invention;

FIG. 2

is a plan view illustrating the ink supply device relating to the embodiment of the invention;

FIG. 3

is a partially broken-out side view illustrating a schematic construction of the ink supply device relating to the embodiment of the invention;

FIG. 4

is a partially broken-out side view enlarged, illustrating an ink supply unit of the ink supply device and a sub ink tank of the ink-jet recording device relating to the embodiment of the invention;

FIG. 5

is a partially broken-out plan view enlarged, illustrating an ink supply unit of the ink supply device and a sub ink tank of the ink-jet recording device relating to the embodiment of the invention;

FIG. 6

is a partially broken-out plan view enlarged, illustrating an ink supply unit of the ink supply device and a sub ink tank of the ink-jet recording device with a positioning arm taking an advanced position, relating to the embodiment of the invention;

FIG. 7

is a partially broken-out plan view enlarged, illustrating an ink supply unit of the ink supply device and a sub ink tank of the ink-jet recording device with the ink supply unit on the way of advance, relating to the embodiment of the invention;

FIG. 8

is a partially broken-out plan view enlarged, illustrating an ink supply unit of the ink supply device and a sub ink tank of the ink-jet recording device with the ink supply unit reaching a ink supply position, relating to the embodiment of the invention;

FIG. 9

is a sectional view illustrating a connection structure of an ink supply port of the ink supply device and an ink supply inlet of the sub ink tank relating to the embodiment of the invention;

FIGS.

10

A through

FIG. 10D

are sectional views illustrating the process of connecting the ink supply port of the ink supply device to the ink supply inlet of the sub ink tank relating to the embodiment of the invention;

FIG. 11

is a sectional view illustrating a connection structure of an exhaust port of the ink supply device and an air outlet of the sub ink tank relating to the embodiment of the invention;

FIG. 12

is a partially broken-out plan view illustrating a drive system that displaces the ink supply unit in the ink supply device relating to the embodiment of the invention;

FIG. 13

is a partially broken-out plan view illustrating a drive system that drives a pump unit in the ink supply device relating to the embodiment of the invention;

FIG. 14

is a graph illustrating a relation between a rotating angle of a cam unit and a position of the positioning arm, and a relation between the rotating angle and a position of the ink supply unit, in the ink supply device relating to the embodiment of the invention;

FIG. 15

illustrates a state that each of the ink supply units advances to the corresponding one of recording head units, in which

FIG. 15A

shows the case of the black ink supply unit, and

FIG. 15B

shows the case of the cyan ink supply unit, in the ink supply device relating to the embodiment of the invention;

FIG. 16

illustrates a state that each of the ink supply units advances to the corresponding one of recording head units, in which

FIG. 16A

shows the case of the magenta ink supply unit, and

FIG. 16B

shows the case of the yellow ink supply unit, in the ink supply device relating to the embodiment of the invention;

FIG. 17

is a timing chart illustrating a connection state of the ink supply port of the ink supply device and the ink supply inlet of the sub ink tank relating to the embodiment of the invention;

FIG. 18

is a partial sectional view of a conventional ink supply device;

FIG. 19

is an explanatory chart illustrating a schematic construction of the conventional ink supply device; and

FIG. 20

is a partial sectional view of the conventional ink supply device illustrated in FIG.

19

.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1

illustrates an ink-jet recording device

12

of the first embodiment of this invention, in which a recording head carriage

14

and its neighboring area are enlarged.

The ink-jet recording device

12

includes a recording medium conveyance member

16

that conveys a recording medium P (for example, paper) in a fixed direction, and a pair of guide members

18

installed along a direction perpendicular to the conveyance direction of the recording medium P so as to face the conveyance route of the recording medium P. These guide members

18

support a recording head carriage

14

. Further, a maintenance station

20

underlies the guide members

18

near the conveyance route of the recording medium P, which comes into contact and becomes disjoined with the recording head carriage

14

(moves up and down in this embodiment) to perform a maintenance operation of capping and suction of ink, etc. A control circuit not illustrated controls this maintenance operation in accordance with a specified condition and timing.

The home position of the recording head carriage

14

is set at a position facing the maintenance station

20

, and a position sensor

22

locates this home position. A main housing

24

retains the recording head carriage

14

, recording medium conveyance member

16

, guide members

18

, maintenance station

20

, and position sensor

22

. Picture information is sent to the recording head carriage

14

through signal lines formed on a flexible board.

Here, the drawing indicates the moving direction (fast-scanning direction) of the recording head carriage

14

with an arrow M, and the moving direction (slow-scanning direction) of the recording medium P with an arrow S.

As illustrated also in FIG.

2

through

FIG. 4

, the recording head carriage

14

is made up with a recording head carriage frame

26

installed movably along the guide members

18

, plural recording heads

28

(four heads, in this embodiment) mounted to project below the bottom (side to face the conveyance route of the recording medium P) of the recording head carriage frame

26

, of which ink discharge openings are formed on the bottom, and sub ink tanks

30

that supply ink to each of the recording heads

28

disposed detachably on the recording head carriage frame

26

. The number of the sub ink tanks

30

corresponds to that of the recording heads

28

, and this embodiment takes on four tanks. Therefore, if the sub ink tanks

30

each supply the recording heads

28

each with different colored inks (black Bk, yellow Y, magenta M, cyan C) and discharge ink drops, it will be possible to record a full-colored picture image. A recording head

28

and a sub ink tank

30

in correspondence constitute a recording head unit

32

relating to this invention. Hereunder, in distinguishing the recording heads

28

, sub ink tanks

30

, and ink supply units

48

described later in correspondence with each of the colors, Bk, Y, M, or C will be put on after the symbol.

And, as shown in

FIG. 1

, the ink-jet recording device

12

of this embodiment conveys the recording medium P by means of the recording medium conveyance member

16

, while making a reciprocating movement of the recording head carriage

14

, discharges ink drops in accordance with picture information, and records an image on the recording medium P.

Each of the sub ink tanks

30

is, as shown in

FIG. 3

, provided with an exhaust port

34

having an air outlet

42

that permits a discharge of air inside the sub ink tank

30

, and an ink supply port

36

below the exhaust port

34

, having an ink supply inlet

44

that permits taking in ink into the sub ink tank

30

. Further, the sub ink tank

30

has an air communication hole

38

formed above the exhaust port

34

, through which air comes in and goes out of the sub ink tank

30

. The going in and out of air through the air communication hole

38

eases a pressure variation inside the sub ink tank

30

. Further, the sub ink tank

30

has an ink sensor

40

attached, which detects an ink quantity inside. The ink sensor

40

sends the detected information of the ink quantity inside the sub ink tank

30

to a control circuit not illustrated.

As shown in

FIG. 1

, the main housing

24

further retains an ink supply device

46

containing plural (four in this embodiment) ink supply units

48

in correspondence with each of the sub ink tanks

30

. The position at which the ink supply unit

48

is to supply ink into the sub ink tank

30

is defined as the ink supply position of the sub ink tank

30

. The ink supply position is also detected by the position sensor

22

in the same manner as the home position. The ink supply position may be set to the same position as the home position; however in this embodiment, it takes a different position.

Further, as shown in FIG.

2

and

FIG. 3

, a main ink tank

50

underlies the ink supply device

46

. The main ink tank

50

contains ink in advance that the ink-jet recording device

12

uses; and the ink supply device

46

supplies the ink into the sub ink tank

30

, which is used for recording images. The main ink tank

50

is disposed to overlap partially with the ink supply device

46

when viewed from the top (in this embodiment, it overlaps substantially completely with the ink supply device

46

), whereby the ink-jet recording device

12

achieves miniaturization as a whole.

As detailed in FIG.

4

and

FIG. 5

, the ink supply device

46

has a fixed frame

52

that is integrally mounted on the main housing

24

of the ink-jet recording device

12

. Further, the fixed frame

52

has a guide frame

54

disposed therein. The guide frame

54

has specific gaps

56

in the cross direction between the fixed frame

52

and the guide frame

54

. The guide frame

54

is movable in the fixed frame

52

within a certain range in the same direction as the moving direction (fast-scanning direction) of the recording head carriage

14

. Further, the gaps

56

have compression coil springs

58

placed therein, which retain the guide frame

54

virtually in the center in the cross direction in the fixed frame

52

. Here, the ‘cross direction’ as simply referred to signifies the same one as the cross direction of the guide frame

54

, which coincides with the fast-scanning direction of the recording head carriage

14

(the direction indicated by the arrow M).

The guide frame

54

has a pair of positioning arms

60

installed near the both ends thereof, which can slide toward the recording head carriage

14

. As shown in FIG.

2

and

FIG. 3

, in the normal state, the positioning arms

60

take a position where they will not come in contact with the recording head carriage

14

. The space between inner sides

60

A (opposing faces) of the positioning arms

60

is defined as equal to the breadth of the recording head carriage frame

26

of the recording head carriage

14

.

As illustrated in FIG.

2

and

FIG. 5

, the positioning arms

60

have tapered faces

62

cut slant to the recording head carriage

14

formed on the end portions of the positioning arms

60

on the side of the recording head carriage

14

. As illustrated by the solid line in

FIG. 2

, if the recording head carriage

14

is displaced in the cross direction to the guide frame

54

when it stops at the ink supply position (the chain double-dashed line in

FIG. 2

shows the normal position of the recording head carriage frame

26

), any one of the tapered faces

62

of the positioning arms

60

will come in contact with a corner of the recording head carriage frame

26

when the positioning arms

60

approach toward the recording head carriage

14

. In this state, if the positioning arms

60

further approach toward the recording head carriage

14

, the movement in this approaching direction will be converted into a cross-directional movement of the guide frame

54

. Thereby, the guide frame

54

moves in the cross direction against an elastic force of the compression coil spring

58

(one of the gaps

56

between the fixed frame

52

and the guide frame

54

is expanded and the other one is narrowed). And, if the positioning arms

60

further approach toward the recording head carriage

14

, as shown in

FIG. 5

, sides

26

S of the recording head carriage frame

26

will come in contact with the inner sides

60

A of the positioning arms

60

, and the recording head carriage

14

and the guide frame

54

will be positioned correctly in the cross direction. Thereby, the four ink supply units

48

are to be integrally positioned to the corresponding sub ink tanks

30

.

As illustrated in FIG.

5

and

FIG. 6

, the positioning arms

60

have pressing piece housings

64

inside thereof, and the pressing piece housings

64

contain pressing pieces

66

that project out partially from the inner sides

60

A of the positioning arms

60

. The pressing pieces

66

are made slidable in the pressing piece housings

64

, and compression coil springs

68

energize the pressing pieces

66

in the direction approaching to the recording head carriage

14

. In the state that the sides

26

S of the recording head carriage frame

26

come in contact with the inner sides

60

A of the positioning arms

60

, and the recording head carriage

14

and the guide frame

54

are positioned correctly in the cross direction, and further, when the positioning arms

60

further advance toward the recording head carriage

14

, then as shown in

FIG. 6

, the pressing pieces

66

receiving an energizing force by the compression coil springs

68

press the recording head carriage

14

. Thereby, the recording head carriage

14

is held between the pressing pieces

66

and the guide members

18

, which prevents looseness of the recording head carriage

14

.

The guide frame

54

has the four ink supply units

48

corresponding to the four sub ink tanks

30

disposed therein. Each of the ink supply units

48

independently slides in each of containers

70

, and approaches and comes off from the corresponding sub ink tank

30

. The area of movement where the ink supply unit

48

approaches and comes off from the recording head carriage

14

(the sub ink tank

30

) is designed not to overlap with the area of movement where the maintenance station

20

approaches and comes off from the recording head carriage

14

, as understood from FIG.

1

. Accordingly, when any one of the ink supply unit

48

and the maintenance station

20

approaches to and comes off from the recording head carriage

14

, the other one does not have to draw back.

As shown in FIG.

3

and

FIG. 4

, each of the ink supply units

48

is provided on an opposing face to the corresponding sub ink tank

30

with an exhaust port

74

at a position corresponding to the air outlet

42

of the sub ink tank

30

, and an ink supply port

76

at a position corresponding to the ink supply inlet

44

of the sub ink tank

30

. When the ink supply unit

48

moves toward the corresponding sub ink tank

30

, the exhaust port

74

is connected to the air outlet

42

, and the ink supply port

76

is connected to the ink supply inlet

44

.

Further, each of the ink supply units

48

has a cap

72

attached at a position corresponding to the air communication hole

38

of the sub ink tank

30

. After the ink supply unit

48

approaches to the sub ink tank

30

, and the exhaust port

74

and the ink supply port

76

are connected to the air outlet

42

and to the ink supply inlet

44

, respectively, when the ink supply unit

48

further approaches the sub ink tank

30

, the cap

72

seals the air communication hole

38

, which deters a flow of air through the air communication hole

38

in the sub ink tank

30

. The shape and the mounting position of the cap

72

are designed to fulfill the above function.

Further, each of the ink supply units

48

has a positioning pin

78

projected toward the sub ink tank

30

. On the other hand, the sub ink tank

30

has a positioning port

80

formed at a position corresponding to the positioning pin

78

. The positioning pin

78

is made up of a cylindrical positioning portion

82

having a constant diameter, and a conically formed guide portion

84

that is tapered toward the front from this positioning portion

82

. The outer diameter of the positioning portion

82

is virtually equal to the inner diameter of the positioning port

80

. As the ink supply unit

48

approaches the sub ink tank

30

, first the guide portion

84

on the front side of the positioning pin

78

goes into the positioning port

80

. Since the guide portion

84

is tapered toward the front, even if the center of the positioning pin

78

is dislocated from the center of the positioning port

80

, the positioning pin

78

is driven to enter the positioning port

80

. And, as the ink supply unit

48

further approaches the sub ink tank

30

, the guide portion

84

drives the positioning pin

78

and the positioning port

80

to gradually move in such a direction that the centers of both coincide. When the positioning portion

82

reaches the positioning port

80

, the center of the positioning pin

78

coincides with that of the positioning port

80

, whereby the ink supply unit

48

and the sub ink tank

30

are positioned individually.

As shown in FIG.

3

through

FIG. 5

, there are specific gaps

86

formed between the upper, lower, right, and left sides of the ink supply unit

48

and the upper, lower, right, and left sides of the container

70

that contains the ink supply unit

48

. The ink supply unit

48

has guide pins

88

projected from these sides, and the guide pins

88

are received in guide grooves

90

formed on these sides of the container

70

.

As understood from

FIG. 4

, the guide groove

90

includes a retaining portion

90

A whose outer diameter is formed slightly wider than that of the guide pin

88

, and a divergent portion

90

B that broadens toward the outside, formed on the end near the sub ink tank

30

. The position of the divergent portion

90

B is set such that the guide pin

88

stays in divergent portion

90

B, in the state that the ink supply unit

48

approaches the sub ink tank

30

and the positioning pin

78

goes into the positioning port

80

. Therefore, in the state that the positioning pin

78

does not enter the positioning port

80

, the guide pin

88

moves inside the retaining portion

90

A, and the ink supply unit

48

slides inside the container

70

without looseness. And, in the state that the positioning pin

78

enters the positioning port

80

, the guide pin

88

reaches the divergent portion

90

B, and a gap is formed between the guide pin

88

and the divergent portion

90

B; and therefore, the ink supply unit

48

becomes movable within a certain range in the vertical and cross directions in the container

70

. Therefore, in this state, namely, in the state that the positioning pin

78

goes into the positioning port

80

, the guide of the ink supply unit

48

by the guide pin

88

and the guide groove

90

is substantially released, and the correct positioning by the positioning pin

78

and the positioning port

80

is accomplished. In addition, the gap between the guide pin

88

and the divergent portion

90

B increases, as the guide pin

88

approaches to the sub ink tank

30

; and the movable range of the ink supply unit

48

in the vertical and cross directions increases accordingly.

Each of the ink supply ports

76

provided on each of the ink supply units

48

has an ink supply pipe

92

installed as shown in FIG.

9

. The ink supply pipe

92

has a pipe body

94

that is formed in a substantially cylindrical shape as a whole. The pipe body

94

has a communication hole

96

formed on the front thereof, through which ink flows out into the sub ink tank

30

. The front portion of the pipe body

94

has a tapered shape that the diameter gradually diminishes toward the front.

The pipe body

94

contains a valve element

98

that is movable in the longitudinal direction, and a bracket

102

that is press-fit in the rear end through an O-ring

100

.

The valve element

98

includes a ring-shaped packing

104

made of an elastic member, a packing holder

106

that holds the packing

104

and is able to slide in the pipe body

94

, and a compression coil spring

108

inserted between the packing holder

106

and the bracket

102

, which energizes the packing holder

106

and the packing

104

toward the communication hole

96

. Normally, the compression coil spring

108

energizes the packing holder

106

and the packing

104

toward the communication hole

96

, and presses the packing

104

onto the circumference of the communication hole

96

to thereby seal the communication hole

96

; however, as shown in FIG.

10

C and

FIG. 10D

, when the packing holder

106

and the packing

104

slide against an energizing force of the compression coil spring

108

, and the packing

104

comes off from the circumference of the communication hole

96

, the ink can be flowed through the communication hole

96

.

The packing holder

106

has a valve contact

110

projected therefrom. The valve contact

110

pierces through the packing

104

, and exposes the front end thereof to the outside through the communication hole

96

; and a valve protrusion

122

described later is designed to press the front end.

The rear end of the bracket

102

is connected to one end of an ink supply tube

124

by way of a cover

112

. As shown in

FIG. 3

, the other end of the ink supply tube

124

is connected to the main ink tank

50

that beforehand stores the ink used for image recording. As described later, when the ink supply port

76

is connected to the ink supply inlet

44

of the sub ink tank

30

, a flow passage is made up from the main ink tank

50

to the sub ink tank

30

.

On the other hand, the ink supply inlet

44

of the sub ink tank

30

has a gasket

114

placed inside thereof, which a gasket cover

112

retains at a specific position so as not to fall off. A circular swollen portion

114

A is formed on the periphery of the gasket

114

, and the swollen portion

114

A is pressed on the inner face of the ink supply inlet

44

, which deters a flow of ink and air through a gap between them. Further, the gasket

114

has a circular inward-projecting lip

114

B formed thereon, and as shown in FIG.

10

C and

FIG. 10D

, the lip

114

B comes in contact with the outside of the inserted pipe body

94

over the whole circumference thereof, which blocks a flow of ink and air through a gap between them. An annular presser ring

116

is placed between the gasket cover

112

and the gasket

114

, which restricts deformation of the lip

114

B within a certain extent while drawing out and putting in the pipe body

94

. This construction, when the pipe body is moved (drawn out and put in) in the ink supply inlet

44

, prevents the lip

114

B from following the drawing out and putting in unexpectedly only to perform as a resistor during that movement, and maintains adhesion of the lip

114

B onto the circumference of the pipe body

94

.

In the ink supply inlet

44

, a valve

118

is placed further inside from the gasket

114

. Normally, the valve

118

is energized by a compression coil spring

120

in the ink supply inlet

44

, and is pressed onto a circular projection

114

C formed on the gasket

114

to close a flow passage of ink. However, as shown in FIG.

10

C and

FIG. 10D

, when the valve

118

slides against an energizing force of the compression coil spring

120

and comes off from the projection

114

C, the flow passage of ink is formed. Here, in this embodiment, the spring constant of the compression coil spring

120

is set greater than that of the compression coil spring

108

.

The valve

118

has the valve protrusion

122

projected therefrom, which faces to the valve contact

110

of the packing holder

106

. As the pipe body

94

is inserted into the ink supply inlet

44

, as shown in

FIG. 10B

, the front of the valve contact

110

comes in contact with the front of the valve protrusion

122

to press each other. This pressure slides the valve element

98

and the valve

118

to form the flow passage of ink. In this embodiment, the spring constant of the compression coil spring

120

is set greater than that of the compression coil spring

108

, and the flow passage of ink is formed inside the pipe body

94

first, and then it is formed inside the ink supply inlet

44

. Thereby, the ink supply unit

48

is liquidly coupled to the sub ink tank

30

. Further, the packing holder

106

and the valve

118

both have communication holes

106

D and

118

D formed, which avoids blocking a flow of ink during liquid coupling.

The positions and shapes of the valve contact

110

and the valve protrusion

122

are speculated as specific ones to form a flow passage of ink after the insertion of the pipe body

94

into the ink supply inlet

44

and at least after the adhesion of the lip

114

B onto the circumference of the pipe body

94

.

FIG. 11

illustrates the exhaust port

74

and the air outlet

42

. The exhaust port

74

and the air outlet

42

are to discharge air inside the sub ink tank

30

, as described later, inside of which ink does not flow. Accordingly, the exhaust port

74

does not contain the valve element

98

inside the pipe body

94

. That is, the communication hole

96

of the pipe body

94

is always open, and the pipe body

94

is provided with the valve contact

110

that can press the valve protrusion

122

. Such a construction also allows forming of a flow passage of air and discharging air inside the sub ink tank

30

from an exhaust tube

126

, since the insertion of the pipe body

94

into the air outlet

42

causes the valve contact

110

to press the valve protrusion

122

to push in the gasket

114

. Here, since the constructions of the exhaust port

74

and the air outlet

42

are stipulated as the same, except the aforementioned, as those of the ink supply port

76

and the ink supply inlet

44

illustrated in

FIG. 9

, the same components and members as those in

FIG. 11

are given the same numeric symbols, and the descriptions will be omitted.

As shown in

FIG. 2

,

FIG. 12

, and

FIG. 13

, on the fixed frame

52

are mounted a drive motor

128

that drives the ink supply device

46

, an ink supply unit shifting gear train

130

that receives a drive force by the drive motor

128

to rotate, a pump driving gear train

132

, and a clutch unit

134

that switches transmission of a rotating force according to the forward rotation and the reverse rotation of the drive motor

128

into the ink supply unit shifting gear train

130

or the pump driving gear train

132

.

The clutch unit

134

includes an input-side gear

138

that engages with a drive gear

136

of the drive motor

128

, a swing arm

140

placed swingably about the shaft of the input-side gear

138

, and an output-side gear

142

attached on one front of the swing arm

140

, which engages with the input-side gear

138

to receive a rotating force. As the drive motor

128

makes the forward rotation, as shown in

FIG. 12

, the swing arm

140

swings counterclockwise, and the output-side gear

142

engages with the ink supply unit shifting gear train

130

. On the other hand, as the drive motor

128

makes the reverse rotation, as shown in

FIG. 13

, the swing arm

140

swings clockwise, and the output-side gear

142

engages with the pump driving gear train

132

.

As understood from

FIG. 2

,

FIG. 3

, and

FIG. 12

, on the fixed frame

52

are laid out cam units

144

in correspondence with each of the ink supply units

48

and the positioning arms

60

(six in total, in this embodiment), so as to rotate coaxially integrally by a rotating force transmitted by the ink supply unit shifting gear train

130

. Each of the cam units

144

is made up of a forward cam

146

that advances the corresponding ink supply unit

48

and positioning arm

60

, and a backward cam

148

that retreats them.

Further, cam follower units

150

are laid out on the fixed frame

52

. Each of the cam follower units

150

is provided integrally with a forward cam follower

152

and a backward cam follower

154

each corresponding to the forward cam

146

and the backward cam

148

, and is able to slide in the same direction as the slide direction of the ink supply unit

48

.

Further, the fixed frame

52

is provided with link mechanisms

158

, each of which is made up of a link

160

capable of swinging about a spindle

156

, and a shifting arm

162

whose one end is pivoted on the front of this link

160

. The other end of the shifting arm

162

is pivoted on the positioning arm

60

or the ink supply unit

48

. Further, the cam follower unit

150

is pivoted on substantially the center of the link

160

. Thereby, as the cam follower unit

150

slides, the link mechanism

158

amplifies the slide, and the result is transmitted to the positioning arm

60

or the ink supply unit

48

.

Each of the cam units

144

has predetermined positions and shapes of the forward cam

146

and the backward cam

148

, so as to advance or retreat the corresponding positioning arm

60

or ink supply unit

48

at a specific timing. Further, the fixed frame

52

has a sensor attached thereon to detect a rotating position of the cam unit

144

, which is not illustrated. On the basis of the rotating angle of the cam unit

144

that is detected by this sensor, a control circuit not illustrated drives the drive motor

128

, sets the initial position of the cam unit

144

, and controls the rotating angle thereof.

Therefore, as shown in

FIG. 14

, as the cam unit

144

turns, receiving a rotating force by the forward rotation of the drive motor

128

, first, at the moment the rotating angle of the cam unit

144

reaches 10°, the forward cam

146

of the cam unit

144

corresponding to the positioning arm

60

advances the positioning arm

60

(refer to FIG.

5

). As the rotating angle of the cam unit

144

reaches 40°, as shown in

FIG. 6

, the positioning arm

60

takes the most advanced position; and until the rotating angle reaches 320°, the positioning arm

60

maintains this position.

And, when the rotating angle of the cam unit

144

reaches 40°, the forward cam

146

of the cam unit

144

corresponding to the black ink supply unit

48

Bk starts advancing the ink supply unit

48

Bk. When the rotating angle reaches 90°, as shown in

FIG. 15A

, the ink supply unit

48

Bk takes the most advanced position, and until the rotating angle reaches 110°, the ink supply unit

48

Bk maintains this position (here, stopping or reversing the rotation of the drive motor

128

will not rotate the cam unit

144

, accordingly the ink supply unit

48

Bk is able to maintain this position, until the drive motor

128

makes the forward rotation next).

As the cam unit

114

further rotates, the backward cam

148

starts to retreat the ink supply unit

48

Bk, and when the rotating angle reaches 140°, the ink supply unit

48

Bk retreats to the initial position. And, when the rotating angle reaches 110° (namely, at the same time the ink supply unit

48

Bk starts to retreat), the forward cam

146

of the cam unit

144

corresponding to the cyan ink supply unit

48

C starts advancing the ink supply unit

48

C. When the angle reaches 160°, the ink supply unit

48

C takes the most advanced position. Thereafter, when the angle stays between 160° and 180°, the ink supply unit

48

C maintains this most advanced position (refer to FIG.

15

B); when the angle is at 180°, the backward cam

148

starts to retreat the ink supply unit

48

C, and when the angle reaches 210°, the ink supply unit

48

C retreats to the initial position. Therefore, the cyan ink supply unit

48

C performs the same action with the delay of the rotating angle 70° against the black ink supply unit

48

Bk. Thereafter, in the same manner, the magenta ink supply unit

48

M performs advance and retreat with the delay of the rotating angle 70° against the cyan ink supply unit

48

C (refer to FIG.

16

A); and the yellow ink supply unit

48

Y performs advance and retreat with the delay of the rotating angle 70° against the magenta ink supply unit

48

M (refer to FIG.

16

B). In this manner, since the ink supply device

46

of this embodiment provides a specific phase difference (70° in this embodiment) to each of the cam units

144

corresponding to each of the ink supply units

48

, it is possible to advance and retreat each of the ink supply units

48

independently with regard to each of the corresponding sub ink tanks

30

.

As shown in

FIG. 13

, as the drive motor

128

makes the reverse rotation, the swing arm

140

being a constituent of the clutch unit

134

swings clockwise, and the output-side gear

142

engages with the pump driving gear train

132

; accordingly, the rotating force of the drive motor

128

is transmitted to a pump spindle

166

being a constituent of a pump unit

164

.

As shown in

FIG. 2

, the pump unit

164

has four roller pumps

168

in correspondence with the exhaust tubes

126

extending from the ink supply units

48

each. As shown in

FIG. 3

, each of the roller pumps

168

has a rotating disc

170

that rotates integrally with the pump spindle

166

, and one or plural (two in this embodiment) rollers

172

mounted near the periphery of this rotating disc

170

. In contrast to this, the exhaust tube

126

is laid out to partially surround the rotating discs

170

, and the roller

172

pushes to crush the exhaust tube

126

locally. Therefore, as the rotating disc

170

rotates clockwise in

FIG. 3

, the rollers

172

moves to squeeze the exhaust tube

126

, and evacuates the fluid (air in this embodiment) inside the exhaust tube

126

into the atmosphere from the other end of the exhaust tube

126

. Here, in each of the roller pumps

168

, the angle of attaching each of the rotating discs

170

is determined in such a manner that the rollers

172

as a whole are arranged in an equal spacing when viewed from the axial direction of the pump spindle

166

. In this embodiment, the pump unit

164

has the four roller pumps

168

installed, and as understood from

FIG. 3

, the rotating discs

170

each are arranged with a displacement of 45°. Therefore, when viewed along the pump spindle

166

, the rollers

172

as a whole are arranged in an equal spacing of the center angle 22.5°. Thereby, the resistance (especially, the rotational resistance resulting from that the roller

172

is pressed by a reaction of the exhaust tube

126

) acting on the pump unit

164

is dispersed, and the pump unit

164

rotates smoothly.

The advance and retreat of the ink supply units

48

by the drive (forward rotation or reverse rotation) of the drive motor

128

and the drive of the pump unit

164

are controlled by a control circuit not illustrated so as not to overlap in the timing with the maintenance operation by the maintenance station

20

.

Next, the function of the ink supply device

46

and the ink-jet recording device

12

of this embodiment, and the method of supplying ink by the ink supply device

46

will be described.

Ejecting ink drops in accordance with image information from the recording head

28

, the recording head carriage

14

moves in the fast-scanning direction, and the recording medium P moves in the slow-scanning direction, whereby images are recorded on the recording medium P. Since the ink supplied from the sub ink tank

30

to the recording head

28

produces the ink drops, the ink inside the sub ink tank

30

decreases, accompanied with the image recording.

As the recording head

28

reaches a specific state that requires any maintenance, the control circuit not illustrated shifts the recording head carriage

14

to the home position, brings the maintenance station

20

close to the recording head

28

, and makes the maintenance station

20

carry out a specific maintenance operation. Thereby, the recording head

28

recovers the optimum state for ink ejection, and as a consequence, the optimum state for ink ejection is maintained constantly, which achieves a high picture quality recording on the recording medium P.

As the ink sensor

40

detects that the ink quantity inside a specific sub ink tank

30

has decreased to a specific quantity, and sends the information detected to the control circuit not illustrated, the control circuit shifts the recording head carriage

14

to the ink supply position. At this moment, the control circuit controls the maintenance station

20

not to operate.

Next, the control circuit controls the drive motor

128

to make the forward rotation in such a manner that the cam unit

144

rotates by the angle corresponding to the specific sub ink tank

30

. For example, in the case of supplying a black ink into the sub ink tank

30

Bk, as understood from

FIG. 14

, the control circuit controls the drive motor

128

to make the forward rotation in such a manner that the cam unit

144

comes to the rotating angle between 90° or larger and 110° or smaller.

At that moment, first, as the rotating angle of the cam unit

144

reaches 10°, a pair of the positioning arms

60

start advancing; and if the recording head carriage

14

is displaced in the cross direction to the guide frame

54

, any one of the tapered faces

62

of the positioning arms

60

comes in contact with a corner of the recording head carriage frame

26

. And in this state, as the positioning arms

60

further approach toward the recording head carriage

14

, the movement in this approaching direction is converted into a cross-directional movement of the guide frame

54

; accordingly, the guide frame

54

moves in the cross direction against the elastic force of the compression coil spring

58

. As the positioning arms

60

further approach toward the recording head carriage

14

, as shown in

FIG. 5

, the sides

26

S of the recording head carriage frame

26

come in contact with the inner sides

60

A of the positioning arms

60

, and the recording head carriage

14

and the guide frame

54

are positioned correctly in the cross direction. For example, if the stop position (ink supply position) of the recording head carriage

14

is slightly dislocated, or if there is such a dislocation due to other various factors, this dislocation will be dissolved, and the four ink supply units

48

will integrally be positioned to the corresponding sub ink tanks

30

.

As the positioning arms

60

further move forward and the pressing pieces

66

come in contact with the recording head carriage frame

26

, the recording head carriage

14

is pressed by receiving the energizing force of the compression coil springs

68

. Thereby, the recording head carriage

14

is held between the pressing pieces

66

and the guide members

18

, which prevents unexpected plays and/or rattling sounds of the recording head carriage

14

.

Here, the rotating angle of the cam unit

144

comes to 40°, which is understood from

FIG. 14

, and since the forward cam follower

152

is pressed to the sub ink tank

30

in the approaching direction by the forward cam

146

of the cam unit

144

corresponding to the black, the ink supply unit

48

Bk advances and starts approaching to the sub ink tank

30

Bk. During the advancement (in the state that the positioning pin

78

is not in the positioning port

80

), the guide pin

88

moves inside the retaining portion

90

A, and the ink supply unit

48

slides in the container

70

of the guide frame

54

without plays.

As shown in

FIG. 7

, the approaching of the ink supply unit

48

to the sub ink tank

30

starts inserting the positioning pin

78

into the positioning port

80

. Here, as understood from

FIG. 17

, in the state before insertion, the packing

104

seals the communication hole

96

in the pipe body

94

(refer to FIG.

10

A), and the inside of the pipe body

94

is sealed. In the same manner, in the inside of the ink supply inlet

44

, the valve

118

adheres onto the projection

114

C of the gasket

114

, which blocks communication with the atmosphere.

Since the guide portion

84

of the positioning pin

78

is tapered toward the front thereof, when the positioning pin

78

is inserted into the positioning port

80

, even if the center of the positioning pin

78

is dislocated from the center of the positioning port

80

, the positioning pin

78

is driven to enter the positioning port

80

. At this moment, the guide pin

88

has reached the divergent portion

90

B, and since a gap is formed between the guide pin

88

and the divergent portion

90

B, the ink supply unit

48

becomes movable within a certain range in the vertical and cross directions in the container

70

. As the ink supply unit

48

further approaches the sub ink tank

30

, the guide portion

84

drives the positioning pin

78

and the positioning port

80

to gradually move in such a direction that the centers of both coincide. And, when the positioning portion

82

reaches the positioning port

80

, the center of the positioning pin

78

coincides with that of the positioning port

80

, whereby a specific ink supply unit

48

and the corresponding sub ink tank

30

are positioned with precision.

Next, as understood from

FIG. 10B

,

FIG. 10C

, and

FIG. 17

, the ink supply port

36

advances, the front of the pipe body

94

enters the ink supply inlet

44

(start of pipe-insertion process), and the front of the valve contact

110

comes into contact with that of the valve protrusion

122

. Here, as the pipe body

94

is further pushed in, the valve contact

110

and the valve protrusion

122

press each other. Since the spring constant of the compression coil spring

108

inside the pipe body

94

is set smaller than that of the compression coil spring

120

inside the ink supply inlet

44

, first while the compression coil spring

108

is shrinking, the pipe body

94

only advances (the valve element

98

stands still in strict sense), and the valve element

98

opens the communication hole

96

. At this moment, the lip

114

B comes into close contact with the circumference of the pipe body

94

to seal the gap between them.

As shown in

FIG. 10C

, as the pipe body

94

further goes into the ink supply inlet

44

, the front of the pipe body

94

comes into contact with the valve

118

; accordingly, the compression coil spring

120

, being pressed by the pipe body

94

through the valve

118

, starts shrinking (the valve element

98

and the pipe body

94

, maintaining a relatively virtually constant positional relation, integrally enter the ink supply inlet

44

). Thereby, the valve

118

comes off from the projection

114

C of the gasket

114

, and the spacing between them starts expanding.

As shown in

FIG. 10D

, in the state that the pipe body

94

goes into the innermost, the ink supply unit

48

comes to the ink supply position, the ink supply port

76

and the ink supply inlet

44

of the sub ink tank

30

is completely connected into a liquid coupling, and the flow passage of ink is formed from the main ink tank

50

to the sub ink tank

30

Bk. At the same time, the connection of the exhaust port

34

and the air outlet

42

is completed. Thereafter, as shown in

FIG. 8

, the cap

72

seals the air communication hole

38

, which blocks communication of air between the inside and the outside of the sub ink tank

30

(end of pipe-insertion process). Therefore, to control the drive motor

128

into the forward rotation and to bring the cam unit

144

into a specific rotating angle makes it possible to connect a specific ink supply unit

48

to the corresponding sub ink tank

30

.

Here, the control circuit not illustrated brings the drive motor

128

into the reverse rotation. The swing arm

140

of the clutch unit

134

swings clockwise in

FIG. 12

, and as shown in

FIG. 13

, the transmission of a rotating force by the drive motor

128

is switched from the ink supply unit shifting gear train

130

into the pump driving gear train

132

. Thereby, while the position of the ink supply unit

48

Bk is being maintained at the ink supply position, the roller pump

168

being a constituent of the pump unit

164

is driven, and the internal air is ejected through the air outlet

42

of the sub ink tank

30

Bk by the ink supply unit

48

Bk. At this moment, since the air communication hole

38

of the sub ink tank

30

Bk is sealed by the cap

72

, the air will not come into the sub ink tank

30

Bk unexpectedly from the air communication hole

38

, and the air can securely be evacuated from the inside of the sub ink tank

30

Bk. Also, the corresponding roller pump

168

is to be driven with respect to the ink supply unit

48

that has not advanced to the ink supply position; however, since the exhaust port

74

is opened, the roller pump

168

will not produce a resistance in the driving.

Since the control circuit brings the drive motor

128

into the reverse rotation for a specific time, a specific quantity of ink is supplied into the sub ink tank

30

. The time for the reverse rotation of the drive motor

128

may be speculated as a preset constant time, or the time for the reverse rotation may be determined by the feedback control on the basis of ink quantity information from the ink sensor

40

.

Next, the control circuit brings the drive motor

128

into the forward rotation. The swing link

160

swings counterclockwise in

FIG. 13

, and as shown in

FIG. 12

, the rotating force by the drive motor

128

is transmitted again to the ink supply unit shifting gear train

130

, and the cam unit

144

rotates accordingly. As understood from

FIG. 14

, when the rotating angle of the cam unit

144

reaches 110°, the ink supply unit

48

Bk starts to retreat, and the cap

72

comes off from the air communication hole

38

, which releases the sub ink tank to the atmospheric pressure.

Further, as understood from

FIG. 17

, since the pipe body

94

starts to retreat from the ink supply inlet

44

(start of pipe-pulling out process), the valve

118

slides by an elastic force of the compression coil spring

120

, and approaches to the projection

114

C of the gasket

114

. And, as the valve

118

returns to the initial position and adheres onto the projection

114

C, the valve element

98

inside the pipe body

94

receives an elastic force of the compression coil spring

108

to slide, and the valve element

98

advances toward the communication hole

96

. Further, the circumference of the pipe body

94

comes off from the lip

114

B during this movement, and the sealing by these is released accordingly. Thus, the valve element

98

returns to the initial position to seal the communication hole

96

, and the pipe body

94

is pulled out from the ink supply inlet

44

(end of pipe-pulling out process).

As the drive motor

128

further makes the forward rotation and the rotating angle of the cam unit

144

comes to 140°, the ink supply unit

48

Bk comes to the end point of retreat, and the ink supply unit

48

Bk returns to the initial position.

As mentioned above, the black ink supply into the sub ink tank

30

Bk is completed, and if another color ink supply to another sub ink tank

30

is needed, the control circuit controls to rotate the drive motor

128

further forward, so that the rotating angle of the cam unit

144

comes to the angle corresponding to the sub ink tank

30

required for the ink supply. If the cyan ink is supplied to the cyan sub ink tank

30

C, for example, the drive motor

128

is made to continue the forward rotation until the rotating angle of the cam unit

144

comes to 160° or more to 180° or less, and as shown in

FIG. 15B

, the cyan ink supply unit

48

C is set to the ink supply position. In this state, the control is made to bring the drive motor

128

into the reverse rotation, to drive the roller pump

168

, and to supply the ink into the sub ink tank

30

C. After the supply of a specified quantity of ink, the control circuit brings the drive motor

128

into the forward rotation, makes the ink supply unit

48

C retreat to the initial position. If the ink supply into the sub ink tank

30

C is not necessary, the control of the drive motor

128

not making the reverse rotation effects the advance and retreat of the ink supply unit

48

C only, and it does not drive the pump unit

164

, which precludes the ink supply into the sub ink tank

30

C.

Thus, as the ink supply into a desired sub ink tank

30

is completed, as understood from

FIG. 14

, in the end (strictly speaking, simultaneously with the retreat operation of the ink supply unit

48

Y), the cam for retreat corresponding to the positioning arm

60

brings the positioning arm

60

in retreat, and returns it to the initial position. With the aforementioned, all the operations of the ink supply into the sub ink tank

30

are completed.

As understood from the above explanation, this embodiment moves the ink supply unit

48

that requires ink supply, corresponding to a specific sub ink tank

30

among plural sub ink tanks

30

, selectively to the ink supply position, and achieves the ink supply into the sub ink tank

30

for each color.

Further, the sub ink tank unit

30

is provided with the air communication hole

38

, which softens a surge pressure variation inside the sub ink tank

30

. Since this softening prevents an unexpected ink leakage from an ink discharge opening of the recording head

28

and an suction of air, and so forth, the recording head unit

32

is able to maintain an optimum state for discharge of ink.

Further, the ink supply into the sub ink tank

30

is achieved by a negative pressurization inside the sub ink tank

30

, and accordingly the inner pressure in the sub ink tank

30

does not rise. Therefore, it is possible to reliably supply a certain quantity of ink into the sub ink tank

30

, in a shorter time without an unnecessary application of load, which is advantageous. Also, the ink supply unit

48

itself can be configured very simply, which achieves a cost reduction.

Since the cap

72

seals the air communication hole

38

during the ink supply, when the roller pump

168

is driven and the air inside the sub ink tank

30

is ejected out, the air will not come into the sub ink tank

30

from the air communication hole

38

, which enables secure pressure reduction inside the sub ink tank

30

, and secure ink supply.

Especially, in this embodiment, the air outlet

42

and the ink supply inlet

44

of the sub ink tank

30

are each connected to the exhaust port

74

and the ink supply port

76

of the ink supply unit

48

, respectively; and thereafter, the air communication hole

38

is to be sealed, and in addition the air communication hole

38

is opened, and thereafter the exhaust port

74

and the ink supply port

76

come off the air outlet

42

and the ink supply inlet

44

. This construction resolves a pressure variation created inside the sub ink tank

30

, accompanied with the connection or disconnection (connection release) operation of the exhaust port

34

and the ink supply port

36

.

The sealing part to seal the air communication hole

38

during the ink supply is not necessarily confined to the cap

72

, and any other measure may be used as long as it can seal the air communication hole

38

. Further, the cap

72

is not necessarily required to be attached to the ink supply unit

48

. For example, a holding member to hold the cap

72

may be provided; however, this embodiment attaches the cap

72

to the ink supply unit

48

, thereby saves such a holding member, reduces the number of components, and lowers the production cost. Further, the displacement (advance and retreat) of the ink supply unit

48

is utilized for sealing the air communication hole

38

or for releasing the sealing, which saves a device to move the cap

72

and simplifies the construction.

The ink supply device of the invention includes: an ink supply unit provided in correspondence with a recording head unit including a recording head that ejects ink drops onto a recording medium on the basis of image information, and a sub ink tank provided with an air communication hole, storing the ink supplied to the recording head, which implements an ink supply by a pressure reduction part reducing a pressure inside the sub ink tank; and a sealing part that at least implements sealing of the air communication hole, while the ink supply unit is reducing the pressure inside the sub ink tank. Therefore, when the ink supply member is in reducing the pressure inside the sub ink tank, the air communication hole of the sub ink tank can be sealed, and the ink supply can be performed securely in a short time.

The entire disclosure of Japanese Patent Application No. 2000-316974 filed on Oct. 17, 2000 including specification, claims, drawings and abstract is incorporated herein by reference in its entirety.

Number	Name	Date	Kind
6048055	Hakkaku et al.	Apr 2000	A
6058984	Sato	May 2000	A
6238042	Kobayashi et al.	May 2001	B1
6390611	Kobayashi et al.	May 2002	B1

Number	Date	Country
1 055 520	Nov 2000	EP
6-238911	Aug 1994	JP
11-240180	Sep 1999	JP

Ink supply device, ink-jet recording device, and method of supplying ink

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

Priority Claims (1)

US Referenced Citations (4)

Foreign Referenced Citations (3)