JPH10329332A - Ink jet recording device - Google Patents

Abstract

(57) [Problem] To prevent air bubbles from stagnating in a filter at the end of an ink supply needle. SOLUTION: Porous material 1 from needle tip 9 to filter 4
2, the ink is guided to the filter 4 through the porous material 12, and the entire upper surface of the filter 4 is wetted with the ink, thereby promoting the passage of bubbles through the filter 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus having a recording head for discharging ink droplets from nozzle openings in response to a print signal, and an ink cartridge for supplying ink to the recording head.

[0002]

2. Description of the Related Art An ink jet type recording apparatus having a recording head and an ink cartridge for supplying ink to the recording head is provided with an ink supply needle communicating with the recording head and an ink supply port provided in the ink cartridge. It is configured such that ink can be supplied by inserting and removing the cartridge from the ink supply needle.

FIG. 5 shows an example of the structure in the vicinity of the ink supply needle A. The connection area between the ink supply needle A and the ink flow path B communicating with the recording head is expanded to form a filter chamber C.
And a filter D made of a non-woven fabric or a mesh material is provided here. The filter D captures bubbles generated in the ink cartridge, or grown bubbles and dust, so as to prevent the ink from flowing into the recording head. It is configured.

[0004]

However, the cross-sectional area of the filter chamber C is increased in order to enhance the trapping of air bubbles by the original function of the filter and to prevent an increase in flow path resistance due to the insertion of the filter D. Therefore, even during ink filling or recovery operation when the ink flow rate passing through the filter D is relatively high, air bubbles cannot be completely discharged from the filter D. In some cases, the portion remained on the surface of the filter D.

The air bubbles E remaining on the filter D
When the filter D grows during the printing operation and covers a large area of the filter D, the area through which the filter D can pass the ink decreases, the flow path resistance becomes extremely high, and the supply of the ink to the recording head is hindered. However, there is a problem that printing becomes impossible.

The present invention has been made in view of such a problem, and an object of the present invention is to prevent ink bubbles from stagnating in a filter and to supply an ink to a recording head with sufficient ink. It is to provide an expression recording device.

[0007]

According to the present invention, there is provided a recording head for ejecting ink droplets by receiving ink from a first ink supply flow path, and a method comprising: An ink jet recording apparatus comprising: a second ink supply path for transporting ink to one ink supply path; and a filter interposed in a connection area between the first ink supply path and the second ink supply path.
The second ink supply path side of the connection area is filled with a porous material whose front surface is in contact with the filter, and the ink is guided from the second ink supply path to the filter via the porous material. I made it.

[0008]

The entire upper surface of the filter is evenly wetted with the ink by the capillary force of the porous material, so that the air bubbles cannot stagnate on the upper surface of the filter, so that the air bubbles pass through the filter quickly.

[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 present invention. A recording head 1 for ejecting ink droplets in response to a print signal is mounted on a carriage (not shown) together with an ink cartridge 2, and is driven by the carriage. The ink reciprocates in the width direction of the recording paper to eject ink droplets from the nozzle openings, and receives ink supplied from the ink cartridge 2 via the ink flow path 3 for the amount consumed in printing.

An upstream second ink supply passage 10 connected to the ink cartridge has an expanding portion 1 at its downstream end.
0a is formed, and the expanded portion 3 of the ink supply needle 5 which becomes the first ink supply path 3 for supplying ink to the recording head
a filter chamber is formed together with the filter 4a.
And a recess 6 for holding the ink supply needle 5 is formed.

The ink supply needle 5 is inserted into the ink supply port 7 of the ink cartridge 2 at the tip, and has a needle tip 9 having an ink guide hole 8 for discharging the ink of the ink cartridge 2 to the recording head 1. Hollow part 1 forming a road
0, and a flange 11 fixed to the concave portion 6. An enlarged portion 10 a is formed in the vicinity of the flange so that a filter chamber can be formed together with the enlarged portion 3 a of the ink flow path 3. .

In the present invention, the ink supply needle 5
Is a material having continuous pores, such as urethane foam, which easily absorbs ink in the hollow portion 10 and the expanded portion 10a and has ink resistance.
Is filled.

In such a structure, first, the ink supply needle 5 is filled with the porous material 12 from the needle tip 9 to the expanded portion 10a, preferably until the ink supply needle 5 is exposed to the extent that the ink supply needle 5 elastically contacts the filter 4. Next, the flange 11 is set on the filter 4 placed in the concave portion 6 and the flange is thermally welded.

In this embodiment, when the ink supply port 7 of the ink cartridge 2 is inserted into the needle tip 9 of the ink supply needle 5, the ink of the cartridge 2 passes through the hollow portion 10 through the capillary of the ink guide hole 8 of the needle tip 9. , And thereafter, it is sucked to the filter 4 by the capillary force of the porous material 12.

According to a preferred embodiment of the present invention, in order to reliably guide ink from the ink guide hole 8 to the filter 4, the average pore diameter of the porous material 12 is smaller than the diameter of the ink guide hole 8, and the filter opening It is good to be larger than the diameter of.

When the ink in the ink cartridge 2 reaches the filter 4 and the recording head 1 is sealed with a cap member to apply a negative pressure to the entire flow path, the ink in the ink cartridge 2 The ink flows into the recording head 1 via the ink cartridge, and the air bubbles stagnating in the flow path from the ink cartridge 2 to the nozzle openings are discharged to the outside together with the ink.

When a drive signal is supplied to the recording head 1 at the stage when the ink filling operation after the replacement of the ink cartridge is completed, ink droplets are ejected from the recording head 1. The ink in the ink cartridge 2 flows into the recording head 1 via the porous material 12 due to the pressure drop on the recording head side due to the ejection of the ink droplets, and the ink is supplied in balance with the consumption.

On the other hand, when air bubbles generated in the ink cartridge flow into the ink supply needle 5, the air bubbles reach the filter 4 through the porous material 12, and the upstream surface of the filter 4 is in contact with the porous material 12. Since the ink is always wet with the ink, the air bubbles cannot stay here and quickly pass through the filter 4 and flow into the downstream expanding portion 3a.

Needless to say, the air bubbles that have flowed into the expanding portion 3a have passed through the filter 4 and are therefore extremely small in size, and the substantial cross-sectional area of the porous material 12 has been reduced. The flow rate of the passing ink is
When the ink flow rate becomes higher than that in the conventional filter chamber in which the porous material 12 is not filled, the recording head 1 is sealed with a cap member and the ink is forcibly ejected for the recovery operation of the ink droplet ejection failure. Is easily discharged to the outside in the ink flow.

In the above-described embodiment, the ink supply needle is filled with a single kind of porous material. However, as shown in FIG. When the porous material 13 having a weak capillary force and the porous material 14 having a strong capillary force are hierarchically accommodated in the expanding portion 10a, the ink can be filtered without losing the negative pressure of the ink cartridge 2 or the flow path resistance. It is possible to reliably guide up to 4.

When a single kind of porous material is used, the porous material 12 is filled so as to protrude from the opening of the expanding portion 10a, and the protruding region is selectively compressed by the filter 4. Thereby, the capillary force in the vicinity of the filter can be increased, and the adhesion between the filter and the porous material 12 can be improved.

Further, by improving the hydrophilicity of the porous material 12, the ink can be more reliably guided to the filter.
In addition, it is possible to prevent bubbles from stagnating inside the porous material 12. In order to improve the hydrophilicity of the porous material 12, a porous material such as urethane is mixed with oxide fine particles such as silica, alumina and titania,
After formation of the porous material, 1,3-propanediamine, 1,
It can be obtained by treating with an amine solvent such as 5-pentadiamine.

Further, when the porous material is exposed to the outside air through the ink guide holes with the ink cartridge pulled out, and there is a possibility that the ink is dried and solidified, particularly when ink (eg, pigment ink) which is easily solidified and solidified is used. In addition, by increasing the capillary force of the porous material on the ink cartridge side of the hollow portion 10 of the ink supply needle 5, the ink holding ability of the easily dried portion can be improved, and the solidification due to drying of the ink can be improved. , Solidification can be prevented.

FIG. 4 shows an embodiment in which an ink cartridge is installed in a box of a recording apparatus and ink is supplied to a recording head via an ink supply tube.
The filter unit 21 is mounted on the carriage together with the print head, and the first ink supply flow path 22 downstream of the filter unit 21 is provided on the print head, and the second ink supply flow path 22 on the upstream side is provided on the carriage.
Are connected to an ink cartridge via an ink supply tube 24.

An enlarged portion 25 is formed in a connection area between the first ink supply flow path 22 and the second ink supply flow path 23, and a filter 26 is provided. The material 27 is filled.

In this embodiment, the porous material 27 is filled only in the expanding portion 25. In such an embodiment as well, it is possible to prevent stagnation of air bubbles. Application to the provided embodiment is likewise possible.

[0028]

As described above, according to the present invention, in the present invention, there is provided a recording head for ejecting ink droplets by receiving ink from the first ink supply passage, and an ink cartridge for supplying ink from the ink cartridge to the first ink supply passage. In the ink jet recording apparatus including a second ink supply path for transporting the ink, and a filter interposed in a connection area between the first ink supply path and the second ink supply path, the second ink supply in the connection area The road side is filled with a porous material whose front surface is in contact with the filter, and ink is guided from the second ink supply path to the filter via the porous material, so that the capillary force of the porous material Since the entire upper surface of the filter is uniformly wetted with the ink, the air bubbles do not stagnate on the upper surface of the filter, and it is possible to prevent an increase in the flow path resistance due to the growth of the air bubbles.

Further, even when the ink cartridge is pulled out, the ink can be held by the capillary force of the porous material, so that the size control of the ink guide hole formed in the needle tip becomes unnecessary and the manufacturing process is simplified. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an ink supply system of an ink jet recording apparatus according to the present invention.

FIG. 2 is an enlarged sectional view showing the vicinity of an ink supply needle in the ink supply system.

FIG. 3 is a cross-sectional view showing another embodiment of the present invention in which the vicinity of an ink supply needle is enlarged.

FIG. 4 is an enlarged cross-sectional view showing an embodiment suitable for a recording apparatus connected to an ink cartridge via an ink supply tube in the vicinity of an ink supply needle.

FIG. 5 is a diagram showing a structure near a filter in a conventional ink jet recording apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording head 2 Ink cartridge 3 First ink flow path 3a Expanding section 4 Filter 5 Ink supply needle serving as second ink supply path 7 Ink supply port 9 Needle tip section 10 Hollow section 10a Expanding section 12 Porous material

Claims (13)

[Claims] A recording head for ejecting ink droplets by receiving ink from a first ink supply passage; a second ink supply passage for transporting ink from an ink cartridge to a first ink supply passage; In an ink jet recording apparatus comprising a filter interposed in a connection area between a first ink supply path and a second ink supply path, a porous member having a front surface in contact with the filter is provided on the second ink supply path side of the connection area. An ink jet recording apparatus which is filled with a porous material and in which the ink is guided from the second ink supply path to the filter via the porous material. 2. The ink cartridge and the recording head are both mounted on a carriage and have a hollow portion where a second ink supply path is connected to a first ink supply path, and a stylus portion which is connected to the ink cartridge. The ink jet recording apparatus according to claim 1. 3. The ink jet recording apparatus according to claim 2, wherein the porous material is filled in the second ink supply path from the needle tip to the filter. 4. The ink jet recording apparatus according to claim 1, wherein the porous material is configured such that the capillary force on the ink inlet side is weak and the capillary force on the filter side is large. 5. The ink jet recording apparatus according to claim 1, wherein the filter chamber is formed by expanding the connection area between the first ink supply path and the second ink supply path. 6. The ink jet recording apparatus according to claim 5, wherein the porous material is filled in an expanded portion of the second ink supply path. 7. The ink jet recording apparatus according to claim 2, wherein an average hole diameter of the porous member is smaller than a diameter of an ink guide hole formed in the needle tip and larger than an opening diameter of the filter. 8. The ink jet recording apparatus according to claim 3, wherein the porous member is configured to increase the capillary force on the needle tip side. 9. The ink jet recording apparatus according to claim 3, wherein a capillary force is changed by changing a compressibility of the porous material. 10. The capillary force is changed by using a plurality of porous materials having different average pore diameters.
9. The ink jet recording apparatus according to 8. 11. The ink jet recording apparatus according to claim 1, wherein the porous material is compressed by the filter. 12. The ink jet recording apparatus according to claim 1, wherein the porous material is subjected to a hydrophilic treatment. 13. The ink jet recording apparatus according to claim 12, wherein oxide fine particles are mixed in the porous material.