JPH10329330A - Ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent air bubbles flowing from an ink cartridge or the like from flowing into a recording head at the time of printing while preventing pressure fluctuation due to movement of a carriage, and easily to the outside at the time of ink filling or the like. To be discharged. SOLUTION: A first ink chamber 32 communicating with an ink cartridge and a second ink chamber 3 communicating with a recording head are provided.
3 and the bubble cannot pass in the ink flow at the time of printing,
In the case of strong flow at the time of ink filling, the ink is communicated through the communication port 34 through which bubbles pass, and the first and second ink chambers 3 are connected.
By sealing the opening surfaces of the nozzles 2 and 33 with the air-shielding elastic film 37 that deforms in response to the ink pressure fluctuation, the ink pressure fluctuation due to the movement of the carriage is prevented.
And prevents the bubbles flowing from the ink cartridge or the like from flowing into the second ink chamber 33 through the communication port 34 during printing. The ink is drawn into the ink chamber 33 and discharged from the recording head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head and a sub-tank mounted on a carriage which moves in the width direction of a recording sheet. The present invention relates to an ink jet recording apparatus that supplies ink to a recording medium.

[0002]

2. Description of the Related Art An ink jet recording apparatus for recording print data by ejecting ink pressurized in a pressure generating chamber from a nozzle as ink droplets onto a recording sheet is known. There is a problem that printing failure occurs due to an increase in viscosity, solidification of ink, adhesion of dust to nozzle openings, and mixing of air bubbles into a pressure generating chamber or the like. For this reason, an ink jet recording apparatus is a capping device for sealing a nozzle opening during non-printing to prevent ink from evaporating, and for applying a negative pressure to the nozzle opening to forcibly discharge ink from the nozzle opening. And a pump unit for supplying a negative pressure thereto.

On the other hand, in order to improve the print quality in color printing, at least dark magenta, light magenta, dark cyan,
2. Description of the Related Art An ink jet recording apparatus using six colors of light cyan, yellow, and black inks has been proposed.

As described above, since the ink cartridges using multicolor inks require ink cartridges for at least six colors, the total weight of the carriage becomes large in a recording apparatus in which the ink tank is mounted on the carriage. Therefore, not only is a large output required for the carriage drive motor, but also there are problems such as a large recoil of the carriage upon carriage return.

In order to solve such a problem, for example, as disclosed in Japanese Patent Publication No. 4-43785, a carriage is provided with a sub-tank which also serves as a pressure damper made of a flexible bag, and is mounted on a box. There has been proposed a separate ink supply system in which ink is pumped from an ink cartridge to a sub-tank and ink is supplied to a recording head via the sub-tank. According to this, not only can the recording head be reliably supplied with ink, but there is an advantage that the entire weight of the carriage can be reduced to achieve high-speed printing and an ink replenishment period can be extended. There is a problem that air bubbles flowing into the sub-tank via the ink supply tube enter the recording head and hinder ink ejection.

[0006]

In order to solve such a problem, there has been proposed an ink supply system in which a recording head, a subtank, and an ink cartridge are connected endlessly to circulate ink to eliminate air bubbles in the recording head. However, since two flow paths are required between the recording head and the ink cartridge, a flow path for the forward path and a flow path for the return path, there is a problem that the flow path structure becomes complicated. The present invention has been made in view of such a problem, and its purpose is to prevent bubbles in the sub-tank from moving to the recording head during the printing period, and to prevent the bubbles in the sub-tank from being moved during the ink filling operation. An object of the present invention is to provide an ink jet recording apparatus capable of discharging bubbles to the outside.

[0007]

In order to solve such a problem, according to the present invention, ink in an ink cartridge is supplied to a sub-tank via an ink supply tube.
In an ink jet recording apparatus that performs printing by supplying ink to a recording head from the sub tank, the sub tank includes a first ink chamber that communicates with an ink cartridge, and a second ink chamber that communicates with the recording head.
In the case of ink flow during printing, air bubbles cannot pass, and in the case of strong ink filling flow, communication is performed through a communication port through which air bubbles pass, and at least one surface of the second ink chamber is subjected to ink pressure fluctuation. It is configured to be sealed by an elastic film that deforms in response.

[0008]

The pressure fluctuation of the ink due to the movement of the carriage is absorbed by the deformation of the elastic film, and the air flowing from the ink cartridge or the like during printing is prevented from flowing into the second ink chamber through the communication port. The bubbles are drawn into the second ink chamber by a strong flow and are discharged from the recording head.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a first embodiment of the present invention. FIG. 1 shows an embodiment of the ink jet recording apparatus of the present invention,
The carriage 1 is connected to a motor 3 by a timing belt 2, and is configured to be guided by a guide member 4 and move in parallel with a platen 5. The first recording head 6 and the second recording head 6 are provided on the surface of the carriage 1 facing the recording paper.
Are mounted side by side in the moving direction of the carriage 1, and sub tank units 8 and 9 having a damper function are mounted on the upper surface.

The above-mentioned ink cartridges 10, 11, 12, and 13 are accommodated in one side of the frame, and are connected to sub-tank units 8 and 9 to be described later by ink supply tubes 14, 15, 16, and 17, respectively.

A capping device 20 having cap members 18 and 19 for sealing the nozzle plates of the recording heads 6 and 7 is provided in a non-printing area on the movement path of the recording heads 6 and 7.

FIG. 2 shows the above-described sub tank unit 8,
9 shows an embodiment of the present invention, in which a first ink chamber 32 and a second ink chamber 33 are formed on a base 30 by two recesses which communicate with each other at a lower end by a partition 31 and a first ink chamber is formed. An ink inlet 35 is formed in the chamber 32 above the communication port 34, and an ink outlet 36 communicating in the upper part of the second ink chamber 33 is formed. It is configured by sealing with a followable air-shielding elastic film 37.

The ink outlet 36 and the second ink chamber 3
A filter chamber 38 formed of a concave portion having a slightly larger opening area than the ink outlet port 36 is formed between the filter chamber 2 and the filter chamber for preventing air bubbles from flowing into the second ink chamber side by a weak flow due to ink consumption during printing. 39 are provided. In addition,
Reference numerals 40 and 41 in the figure denote connecting portions to the tube.

FIG. 3 shows an ink supply system in the recording apparatus, taking one ink cartridge 10 as an example. The sub-tank 8 has an ink supply tube 14 connected to an ink inlet 35, The ink supply needle 50 at the end is connected to the ink supply port 10b of the ink bag 10a housed in the ink cartridge 10, and the ink outlet 36 is connected to the ink introduction port 6a of the recording head 6 by the tube 51.

A cap member 18 for sealing the recording head 6
Is connected to a suction port of a suction pump 54 via a tube 53. A discharge port of the suction pump 54 is connected to a waste ink tank 56 by a tube 55. The power for driving the suction pump 54 is not limited to a dedicated motor,
A member that does not require an operation at the time of suction, for example, the power of a paper feed motor can be used.

In this embodiment, when the ink cartridge 10 is newly installed, an initial filling command is issued by a switch or the like of a control panel provided on the surface of the recording apparatus case.

The carriage 1 moves to the home position, seals the recording heads 6 and 7 with the cap members 18 and 19, and operates the suction pump 54. This negative pressure simultaneously deforms the air-shielding elastic film 37 of the sub-tank 8 so as to make the ink chamber side convex, and at the same time, the sub-tank 8 and the ink supply tube 14 which form the ink supply passage through the recording head 6 To draw the ink of the ink cartridge 10 into the first ink chamber 32 via the ink supply tube 14 (FIG. 4 (I)).

The bubbles remaining in the cartridge 10 or the ink tube 14 flow into the first ink chamber 32 along with the flow of ink. In a state where a strong negative pressure is acting, the liquid level of the ink in the first ink chamber 32 is about the height of the communication port 34, so that the bubbles B are also transferred to the second ink chamber 33 via the communication port 34. Flow in.

The ink flows into the second ink chamber 33, rises to the ink outlet 36 by buoyancy, is pulled by a strong pressure, passes through the filter 39, flows into the recording head 6 together with the ink, and passes through the recording head 6. It is discharged outside (Fig. 4 (II)).

When the initial filling of the ink is completed, the operation of the negative pressure via the recording head 6 is stopped, and the air-shielding film 3 is removed.
7 returns to the original state, and the liquid level of the ink in the first ink chamber rises (FIG. 4 (III)).

When printing is executed in this state, the ink consumed by the recording head 6 by printing flows from the ink cartridge 10 into the first ink chamber 32 of the sub tank 8. Although the air bubbles B contained in the ink supply tube 14 and the ink cartridge 10 also flow into the first ink chamber 32 together with the ink, they rise due to buoyancy and are blocked by the wall surface at a position higher than the communication port 34, so that the second ink chamber 32 is blocked. Since the movement to the ink chamber 33 is prevented, it has to be moved to the space above the first ink chamber, and cannot flow into the second ink chamber 33.

In this embodiment, if the ink inlet 35 to the first ink chamber 32 is formed above the communication port 34, the bubble B flowing from the ink inlet 35
Is positioned as close to the liquid surface as possible, and the inflow of bubbles into the second ink chamber 33 can be reliably prevented.

Therefore, air bubbles flowing from the ink inlet 35 during printing cannot enter the recording head 6. Further, the air-shielding elastic film 37 responds to the ink pressure fluctuation caused by the movement of the carriage 1 to suppress the propagation of the ink pressure to the recording head 6 as much as possible (see FIG.
V)).

FIG. 5 shows a second embodiment of the present invention, in which a first ink chamber 61 and a second ink chamber 62 are divided by a partition 63 so as to be in a vertical relationship. The ink supply port 64 is communicated with the lower portion of the
The ink outlet 6 communicates with the bottom surface of the second ink chamber 62.
5, and the upper portion of the second ink chamber 62 is communicated with the upper portion of the second ink chamber 62 through the communication port 66 from above the ink inlet 64.
Further, the lower surface 63a of the middle partition 63 is formed on a slope with the communication port side 66 facing upward, and the first and second opening surfaces are sealed with an air-tight elastic film 67.

In this embodiment, when the ink is filled, the ink level E1 drops and is located near the communication port 66, and the ink flow is fast. And flows into the second ink chamber 62. Then, the ink is drawn by the fast ink flow, drawn to the outlet 65 along the slope, and is discharged from the recording head 6 (FIG. 6A).

When ink filling is completed, the ink level E2 in the first ink chamber 61 rises above the communication port 66 and the speed of the ink flow is low.
, And even if the bubble B flows into the second ink chamber 62, it returns to the first ink chamber 61 from the communication port along the slope 63a by buoyancy against the weak ink flow. That is, bubbles are prevented from flowing into the recording head 6 during the printing period (FIG. 6B).

FIG. 7 shows a third embodiment of the present invention, in which a first ink chamber 71 and a second ink chamber 72 are arranged obliquely so as to be in a vertical relationship. The ink supply port 74 is communicated with the deepest area of the first ink chamber 71, and the ink outlet port 75 is formed by communicating with the narrow area of the second ink chamber 72. The upper part of the second ink chamber 72 is communicated with the upper part of the second ink chamber 72 through the communication port 76 from above the part 74, and the first and second opening surfaces are sealed with the air-shielding elastic film 77. A filter chamber 78 is formed so as to communicate with the ink outlet 75, and a filter 79 is provided on the second ink chamber side 72.

In this embodiment, when the ink is filled, the ink level E1 of the first ink chamber 71 drops and is located near the communication port 76, and the ink flow is fast. Riding easily passes through the communication port 76 and flows into the second ink chamber 72. Then, the ink is drawn by the fast ink flow, is drawn to the outlet 75 along the inclination of the lower surface of the middle partition 73, passes through the filter 79, and is discharged from the recording head 6 (FIG. 8A).

At the stage when ink filling is completed, the ink level E2 in the first ink chamber 71 rises above the communication port 76 and the speed of the ink flow is low.
, And even if bubbles B flow into the second ink chamber 72, the first ink flows from the communication port 76 along the slope of the middle partition 73 by buoyancy against the weak ink flow.
The ink is returned to the ink chamber 71, and further blocked by the filter 79, so that bubbles are prevented from flowing into the recording head 6 during the printing period (FIG. 8B).

FIG. 9 shows a fourth embodiment of the present invention, in which a first ink chamber 81 and a second ink chamber 82 are divided by a partition 83 so as to be in a vertical relationship. A concave portion is formed in a part of the middle partition 83 to form a small chamber 82a above the second ink chamber 82, and the first ink chamber 8 is formed.
1, the ink supply port 84 is communicated with the small chamber 82a of the second ink chamber 82 to form an ink outlet 85, and a rising portion 83a is formed at the tip of the middle partition 83 to form an ink flow. Above the inlet 84, the second ink chamber 82 is communicated with the first ink chamber 81,
The opening 82 is sealed with an air-tight elastic film 86. Then, a filter chamber 87 is formed by communicating with the ink outlet 85, and a filter 88 is provided on the second ink chamber side.
Is provided.

In this embodiment, when the ink is filled, the ink level E1 of the first ink chamber 81 drops and is located near the rising portion 83a and the ink flow is fast. Riding easily flows into the second ink chamber 82. And the small chamber 8 is drawn by the fast ink flow
2a, the recording head 6
(FIG. 10A).

When the ink filling is completed, the ink level E2 in the first ink chamber 81 rises above the upper end of the rising portion 83a and the speed of the ink flow is low. 82 cannot flow.

Further, even if bubbles B flow into the second ink chamber 72, they are blocked by the filter 88, so that bubbles are prevented from flowing into the recording head 6 during the printing period (FIG. 1).
0 (b)).

FIG. 11 shows a fifth embodiment of the present invention. In this embodiment, only the second ink chamber 92 which communicates with the ink outlet 91 at the lower portion is provided with the air-shielding elastic film 9.
3, and a filter 96 is provided so as to divide the first ink chamber 95 communicating with the ink supply port 94 at the upper part into two regions, and a communication port 97 formed below the ink inflow port 94. The filter is configured to communicate with the second ink chamber 92 on the downstream side of the filter 96.

In this embodiment, when the ink is filled, the bubbles B are easily filtered by the rapid ink flow.
Pass through. Then, the bubbles that have moved to the downstream side of the filter 96 and the ink liquid level that has dropped to the vicinity of the communication port 97 easily pass through the second ink chamber 82 by riding on the fast ink flow, and flow into the second ink chamber 82, where the large ink is secured. It is accommodated in the upper space 92a (FIG. 12A).

At the stage when the ink filling is completed, the air bubbles adhering to the filter 96 are removed to reduce the flow path resistance, and the air bubbles entering from the inflow port 94 during the printing period are blocked by the filter 96. Even if the ink can pass, the ink liquid level on the downstream side of the filter 96 is higher than the communication port 97, so that the ink level cannot be passed through the communication port 97 and is captured downstream of the filter 96.

On the other hand, air bubbles mixed into the ink in the second ink chamber 92 overcome the weak ink flow during printing and move to the upper space 92a by buoyancy, and therefore do not pass through the ink outlet 91 at the bottom. (FIG. 12 (b)). In addition,
As long as a hydrophobic air-permeable filter is provided above the second ink chamber 92, the air in the second ink chamber 92 can be easily removed.

In the above-described embodiment, the recording apparatus for supplying the ink of the ink cartridge housed in the box to all the recording heads via the ink supply tube has been described as an example. The same effect can be obtained even when the present invention is applied to a recording apparatus in which a recording head that receives supply of ink from a mounted ink cartridge is mounted.

[0039]

As described above, according to the present invention, there is provided an ink jet recording apparatus for supplying ink from an ink cartridge to a sub-tank via an ink supply tube and supplying ink from the sub-tank to a recording head for printing. , The sub-tank has a first ink chamber communicating with the ink cartridge and a second ink chamber communicating with the recording head.
Are communicated with the ink chamber through a communication port through which air bubbles cannot pass when the ink flows during printing, and when the ink flows strongly, and at least one surface of the second ink chamber. Is sealed by an elastic film that deforms in response to the pressure fluctuation of the ink, so that the pressure fluctuation of the ink due to the movement of the carriage is absorbed by the deformation of the elastic film,
Also, during printing, air bubbles flowing from the ink cartridge or the like are prevented from flowing into the second ink chamber by the communication port, thereby preventing the air bubbles from flowing into the recording head. It can be easily discharged from the recording head by being drawn into the chamber.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of an ink jet recording apparatus of the present invention.

FIGS. 2A and 2B are a front view and a cross-sectional view, respectively, illustrating an embodiment of a sub-tank.

FIG. 3 is a diagram showing one embodiment of an ink supply system of the ink jet recording apparatus.

FIGS. 4A to 4C are a front view (FIG. 4A) and a cross-sectional view (FIG. 5B) showing the behavior of the ink in the sub-tank at the time of ink filling and printing, respectively. .

FIGS. 5A and 5B are a front view and a cross-sectional view, respectively, illustrating an embodiment of a sub-tank.

FIGS. 6A and 6B are diagrams showing the behavior of the ink when the sub-tank is filled with ink and when the ink is completely filled, respectively.

FIGS. 7A and 7B are a front view and a cross-sectional view, respectively, illustrating an embodiment of a sub-tank.

FIGS. 8A and 8B are diagrams showing the behavior of the ink when the sub-tank is filled with ink and when the ink is completely filled, respectively.

FIGS. 9A and 9B are a front view and a cross-sectional view, respectively, illustrating an embodiment of a sub-tank.

FIGS. 10A and 10B are diagrams showing the behavior of the ink when the sub-tank is filled with ink and when the ink is completely filled, respectively.

FIGS. 11A and 11B are a front view and a cross-sectional view, respectively, showing an embodiment of a sub-tank.

FIGS. 12A and 12B are diagrams showing the behavior of the ink when the sub-tank is filled with ink and when the ink is completely filled, respectively.

[Explanation of symbols]

 Reference Signs List 1 carriage 8, 9 sub tank 10 to 13 ink cartridge 14 to 17 ink supply tube 18, 19 cap member 31 partition 32 first ink chamber 33 second ink chamber 34 communication port 35 ink inlet 36 ink outlet 37 shielding Temper elastic membrane 38 Filter chamber 39 Filter member 54 Suction pump 56 Waste ink tank

Claims (8)

[Claims] 1. An ink jet recording apparatus which supplies ink from an ink cartridge to a sub-tank via an ink supply tube and supplies ink from the sub-tank to a recording head to perform printing, wherein the sub-tank communicates with the ink cartridge. First
Between the first ink chamber and the second ink chamber communicating with the recording head, air bubbles cannot pass through the ink flow during printing,
In the case of a strong flow at the time of ink filling, the ink is communicated through a communication port through which bubbles pass, and at least one of the second ink chambers
An ink jet recording apparatus in which two surfaces are sealed with an elastic film that deforms in response to ink pressure fluctuations. 2. The first ink chamber and the second ink chamber,
2. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is arranged in a horizontal direction and the communication port is formed at a low place. 3. The ink jet recording apparatus according to claim 2, wherein an ink supply port for supplying ink from the sub-tank to the first ink chamber is formed above the communication port. 4. The first ink chamber and the second ink chamber,
2. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is arranged in a vertical relationship, and the communication port is located above the ink inlet. 5. The ink jet recording apparatus according to claim 4, wherein a slope is formed on a lower surface of a member separating the first ink chamber and the second ink chamber so that the communication port side is upward. 6. A small chamber communicating with the second ink chamber is formed on a lower surface of a member separating the first ink chamber and the second ink chamber, and an outlet is formed to communicate with the small chamber. Item 6. An ink jet recording apparatus according to item 5. 7. The ink jet recording apparatus according to claim 1, wherein the first ink chamber is divided by a filter. 8. The ink jet recording apparatus according to claim 1, wherein a filter is provided between the ink outlet and the second ink chamber.