JP2000296622A - Ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the air bubble amt. remaining in a filter chamber at a time of cleaning while achieving the expansion of a filter area. SOLUTION: In an ink jet recording apparatus wherein a filter chamber increased in its flow channel width to be provided with a filter is formed on the way of the ink supply flow channel 13 connected not only to an ink cartridge at one end thereof but also to an ink jet recording head at the other end thereof, elastomers 25a-25c are provided to the inner surface of the side wall 22 of the filter chamber to constitute a double side wall and the outer peripheral surfaces of the upstream end parts of the elastomers and the outer peripheral surfaces of the downstream end parts thereof are airtightly fixed to the inner surface of the side wall and the flow channel is contracted by inward deformation of an intermediate part 25c having no elastomers fixed thereto in such a state that the ink supply flow channel is evacuated.

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 for recording characters and the like on recording paper by ejecting ink droplets from nozzles, and more particularly to an ink for supplying ink from an ink supply container to an ink jet recording head. The present invention relates to an improvement of a filter chamber provided in a supply flow path.

[0002]

2. Description of the Related Art In an ink jet recording apparatus,
A filter chamber is formed in the ink supply path for supplying ink from the ink cartridge to the ink jet recording head, generally at the base of the ink supply needle inserted into the ink cartridge. Foreign matter in the ink is formed in the filter chamber. A filter is installed to capture and remove foreign substances and to prevent foreign substances from flowing into the recording head. In the filter, it is necessary to increase the cross-sectional area of the ink supply flow path in order to suppress the dynamic pressure when ink passes through the filter and to secure the ink supply amount. For this reason, in the filter chamber located immediately before the filter, the flow velocity of the ink decreases, and not only foreign matter but also air bubbles remain on the filter.

[0003] To remove air bubbles remaining on the filter,
Close the cap member with the recording head in close contact, close the cap, and forcibly suck the ink in the ink supply flow path with the suction pump connected to the cap member. Was. This cleaning is performed immediately after the main power is turned on, at the start of printing after a lapse of a certain time from the end of printing, at the start of printing after replacing the ink cartridge, or when the operator finds a printing defect. Was.

[0004]

However, if the filter area is increased in order to reduce the passage resistance of the filter as the printing speed increases, there is a problem that the amount of bubbles remaining on the filter also increases. In addition, when the filter area is enlarged, there is a problem that it becomes more difficult to remove air bubbles remaining on the filter.

That is, when the area of the filter is increased, even if the suction is forcibly suctioned from the recording head side by the suction pump, the flow of ink in the filter chamber is not only slowed down by the increased filter area, but also reduced. There is a large difference in the flow velocity of the ink in the filter chamber, such as the flow of the ink in a streamline avoiding the air bubbles, and these together reduce the air bubble elimination efficiency. For this reason, there is a limit in increasing the filter area.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and has as its object to provide an ink jet recording apparatus capable of reducing the amount of bubbles remaining in a filter chamber during cleaning even when the area of the filter is increased.

[0007]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above object. According to the present invention, one end is connected to an ink supply container and the other end is connected to an ink jet recording head. In an ink jet recording apparatus in which a filter chamber having a filter provided with an increased flow path width is formed in the middle of the ink supply flow path, an elastically deformable portion made of an elastic body is provided on a side wall of the filter chamber, and the recording is performed. An ink jet recording apparatus wherein an elastic deformation portion is deformed inward to reduce the flow path in a state where the pressure in the ink supply flow path is reduced from the head side.

Here, the state in which the pressure in the ink supply flow path is reduced from the recording head side is a state in which the pressure is forcibly reduced by, for example, a suction pump. The normal printing state in which the ink flows down in the supply flow path is not included.

According to a second aspect of the present invention, there is provided a filter chamber in which one end is provided in an ink supply container, and the other end is provided in the middle of an ink supply passage connected to an ink jet type recording head by increasing a passage width and providing a filter. In the ink jet type recording apparatus, a double elastic side wall is provided by attaching a separate elastic body to the inner surface of the side wall of the filter chamber, and the outer peripheral surface of the upstream end and the downstream end of the elastic body are formed. The outer peripheral surface is airtightly fixed to the inner surface of the side wall of the filter chamber, and is fixed between the upstream end and the downstream end of the elastic body in a state where the pressure in the ink supply flow path is reduced from the recording head side. An ink jet type recording apparatus characterized in that an intermediate portion not formed is deformed inward to reduce a flow path.

According to a third aspect of the present invention, the side wall of the filter chamber is formed so as to be tapered from the upstream end to the downstream filter side, and the ink supply container is provided at the front end of the filter chamber. 3. A hollow shaft portion of an ink supply needle inserted into the nozzle is integrally formed.
2. An ink jet recording apparatus according to (1).

According to a fourth aspect of the present invention, a side wall of the filter chamber is provided at a part thereof with an air communication hole for communicating the outer peripheral surface of the separate elastic body to atmospheric pressure. The ink jet recording apparatus according to claim 2 or 3, wherein:

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

FIG. 1 is a perspective view showing an embodiment of an ink jet recording apparatus 1, and FIG. 2 is a sectional view of a carriage 3 on which an ink cartridge 2 as an ink supply container is mounted and a recording head 4.

The recording head 4 of the ink jet recording apparatus 1 is fixed downward on the lower surface of the carriage 3, and is driven by a carriage driving motor 5 to drive a guide member 6.
Reciprocating in the width direction of the recording paper 7 while being guided by the printer, ejects ink droplets from nozzle openings in response to print signals, and records characters, figures, and the like on the recording paper 7. Then, the recording head 4 is sealed from below to prevent drying of the nozzle openings in the non-printing area deviated from the recording paper 7, and a negative pressure is applied when ink is filled after replacing the ink cartridge 2. Is provided with a cap member 8 and a wiping member 9 for supplying the water.

As shown in FIG. 2, an ink supply needle 11 is provided on the bottom of the cartridge holder 10 of the carriage 3 so as to protrude upward. When the ink cartridge 2 is mounted on the cartridge holder 10, the ink supply needle The ink 11 is inserted into the ink outlet 12 of the ink cartridge 2, and the ink derived from the ink supply needle 11 is supplied to the recording head 4 via the ink supply channel 13. Note that FIG.
Reference numeral 4a in the middle denotes a nordule plate in which a plurality of nozzle openings are arranged.

As described above, one end of the ink supply channel 13 of the ink jet recording apparatus 1 is connected to the ink cartridge 2 and the other end is connected to the ink jet recording head 4. Is formed, and a filter is provided in the filter chamber. In the present embodiment, the filter chamber 14 is integrally formed at the root of the ink supply needle 11, and an ink collecting chamber 16 having substantially the same size as the opening of the filter chamber 14 is formed on the cartridge holder 10 side. When fixing the ink cartridge 2 to the ink cartridge 2, a plate-like filter 15 is sandwiched between the lower end opening of the filter chamber 14 and the ink collecting chamber 16.

The ink supply needle 11 is, as shown in FIG.
A hollow shaft portion 21 having an inlet 20 formed at a sharp end, a filter chamber 14 formed by expanding a side wall 22 downwardly from the hollow shaft portion 21 in a tapered shape, and a large-diameter opening edge of the upper filter chamber 14. Root part 23 and root part 2 slightly above root part 23
A plastic member composed of a flange portion 24 having a diameter larger than 3 and a separate elastic body 25 is attached to the inner surface of the side wall 22 as a movable film to form a double side wall. ing.

The elastic body 25 is formed by molding an elastic material such as butyl rubber into a hollow cylindrical shape having a narrowed front end (upstream) and a widened base (downstream) along the side wall 22 as a whole. The outer peripheral surface of the upstream end 25a and the downstream end 25
The outer peripheral surface b is hermetically fixed to the inner peripheral surface of the side wall 22 of the filter chamber 14 by fixing means such as an adhesive.
When the ink is sucked at a higher speed than during normal printing, the negative pressure of the ink supply flow path 13 causes the elastic body 2 to be sucked.
The diameter of the intermediate portion 25c, which is not fixed between the upstream end portion 25a and the downstream end portion 25b, is reduced (see FIG. 4). The upstream end 25a of the elastic body 25
Intermediate part 2 between the lower end 25b and the downstream end 25b
5c is a strength that does not cause elastic deformation during normal printing. In the case of this embodiment, the upstream end portion 25 of the elastic body 25
a and the downstream end portion 25b are configured to be thicker than the intermediate portion 25c therebetween to obtain a required rigidity. In other words, the intermediate portion 25c is formed to be thin.

In this embodiment, the filter chamber 1
One or a plurality of air communication holes 26 are provided at positions corresponding to the intermediate portion 25c so that the elastic body 25 can be largely deformed inward at the time of decompression by high-speed suction of ink on the side wall 22 of 4,
The pressure on the outer peripheral surface side of the elastic body 25, that is, the back pressure is set to the atmospheric pressure.

FIG. 3 shows the operating state of the elastic body 25 during normal printing, and FIG. 4 shows the deformed state of the elastic body 25 during cleaning.

In the normal printing shown in FIG. 3, since the flow rate of the ink is relatively slow, the pressure difference between the front and back of the elastic body 25 is small, and the elastic body 25 is not deformed. Therefore, as shown in the figure, the flow path is not reduced by the elastic body 25, and
Since the filter 15 maintains a predetermined large filter area as usual, high-speed printing can be performed without increasing the dynamic pressure. Since the filter chamber 14 has a tapered shape that expands downward, bubbles are trapped so as to be in contact with the upper inner surface of the filter chamber 14, and do not come into contact with the filter 15 until they expand relatively large.

On the other hand, in the cleaning mode, a suction pump (not shown) connected to the cap member 8 is operated while the lower surface of the recording head 4 is sealed from below by raising the cap member 8 of FIG. For example, about 0.6 cc of ink is sucked from the nozzle plate 4a side. If necessary, a second cleaning mode in which the amount of ink is increased, and a third cleaning mode in which the amount of ink is slightly larger than the amount of ink in the second cleaning mode may be executed.

Due to these ink suctions, the pressure in the ink supply flow path 13, that is, the inside of the filter chamber 14 is reduced, and the pressure inside the filter chamber 14 becomes negative with respect to the atmosphere. As shown by arrows in FIG.
Atmospheric pressure acts in a direction to press the outer peripheral surface of the elastic body 25. Due to the action of the atmospheric pressure, the elastic body 25 contracts inward as shown in FIG. 4, and the ink supply flow path 13 changes from a divergent type to a substantially straight type. It becomes thin. Therefore, the flow velocity of the ink is increased, and the air bubbles 30 trapped in the filter chamber 14 are sufficiently removed along with the ink flow.

As described above, the ink supply needle 11 of the present embodiment has the hollow shaft portion 21 connected to the ink cartridge 2 in the substantially upper half portion as in the conventional case, and has a divergent type on the downstream side. It has a filter chamber 14. On the other hand, unlike before,
The side wall 22 of the filter chamber 14 is doubly surrounded by a separate elastic body 25, and the filter chamber 1 is
Due to the reduced pressure in 4, the separate elastic body 25 is deformed in the direction of decreasing the inner diameter, and the ink supply flow path 13 is apparently changed from the divergent type to the straight type.

Therefore, at the time of cleaning, the ink supply flow path 13 changes from a divergent type to a substantially straight type so that the difference between a portion where the ink flow speed is slow and a portion where the ink flow speed is fast becomes small. Becomes smaller. Further, during normal printing, since the flow velocity of the ink is low, the flow path is not deformed by the elastic body 25, and the filter area can be increased. When the ink supply needle 11 is inserted into the ink outlet 12 of the ink cartridge 2, a compressive force acts on the filter chamber 14.
Since the side wall 22 has sufficient rigidity, there is no possibility of damage.

Although the filter chamber 14 is provided integrally with the base of the ink supply needle 11 in the above-described embodiment, the filter chamber 14 in the present invention is not limited to this. Any site may be used.

Further, the side wall 22 of the filter chamber 14 is not limited to the double side wall with the elastic body 25 provided inside the side wall 22 of the filter chamber 14 but deforms inward when the ink supply flow path 13 is depressurized. Alternatively, the flow path may be configured to be reduced.
For example, as in an ink supply needle 11 ′ shown in FIG. 5, the filter chamber 14 has a substantially triangular pyramid shape or a substantially quadrangular pyramid shape, and a portion corresponding to a ridge is formed of a skeleton member 31 having sufficient strength, and a substantially triangular shape. A film of an elastic body such as a butyl rubber film is stretched as an elastic deformation portion 32 in a portion surrounded by the skeleton member 31 of
The elastic deformation portion 32 that does not deform during normal printing is
When the pressure in the ink supply channel 13 is reduced, the elastic deformation portion 32 may be deformed inward by the atmospheric pressure to reduce the size of the channel. Thus, the elastically deformable portion 32
When the is substantially flat, it is easily deformed by a small force, so that the size of the suction pump can be reduced.

[0028]

According to the present invention as described above, the following effects can be obtained.

According to the first aspect of the present invention, the elastically deformable portion made of an elastic body is provided on the side wall of the filter chamber, and the elastically deformable portion is deformed inward while the pressure in the ink supply flow path is reduced from the recording head side. To reduce the flow path.
According to the invention, a separate elastic body is attached to the inner surface of the side wall of the filter chamber to form a double side wall, and the outer peripheral surface of the upstream end and the outer peripheral surface of the downstream end of the elastic body are separated. In a state where the inside of the ink supply flow path is depressurized from the recording head side while the air supply is fixed airtightly to the inner surface of the side wall of the filter chamber, the unfixed intermediate portion between the upstream end and the downstream end of the elastic body is inside. In order to reduce the size of the flow path during normal printing, the filter area is secured with a large flow path as specified during normal printing, and the apparent ink supply flow path is reduced during cleaning. As a result, the flow rate of the ink can be increased, and the difference between the fast and slow portions of the ink flow in the filter chamber can be eliminated. Therefore, the bubbles in the filter chamber can be effectively discharged along with the ink flow, and the amount of bubbles remaining in the filter chamber can be reduced. For this reason, it is possible to smoothly expand the filter in accordance with the high-speed printing, and it is possible to improve the printing quality.

According to the third aspect of the present invention, the side wall of the filter chamber is formed so as to be tapered from the upstream end to the downstream filter side, and is provided in the ink supply container at the front end of the filter chamber. Since the hollow shaft portion of the ink supply needle to be inserted is integrally formed, the configuration can be simplified and the assembling operation is easy.

According to the fourth aspect of the invention, the side wall of the filter chamber is provided at a part thereof with an air communication hole for communicating the outer peripheral surface side of the separate elastic body to atmospheric pressure. At the time of pressure reduction due to high-speed suction of ink, the separate elastic body is greatly deformed toward the pressure reduction side by the effect of atmospheric pressure, and a large amount of deformation can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of an ink jet recording apparatus.

FIG. 2 is a sectional view of an ink cartridge and a recording head.

FIG. 3 is a cross-sectional view illustrating an internal state of the ink supply needle during printing.

FIG. 4 is a cross-sectional view illustrating an internal state of the ink supply needle at the time of cleaning in which the pressure in the ink supply channel is reduced.

FIG. 5 is a perspective view of another embodiment of the ink supply needle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink jet recording head 2 Ink cartridge 3 Carriage 4 Recording head 5 Carriage drive motor 6 Guide member 7 Recording paper 8 Cap member 9 Wiping member 10 Cartridge holder 11 Ink supply needle 12 Ink outlet 13 Ink supply channel 14 Filter chamber 15 Filter Reference Signs List 20 Ink supply needle inlet 21 Hollow shaft part of ink supply needle 22 Side wall of filter chamber 23 Root 24 Flange 25 Elastic body 25a Upstream end of elastic body 25b Downstream end of elastic body 25c Intermediate between elastic bodies Part 26 atmosphere communication hole 30 air bubble 31 skeletal member 32 elastic deformation part

Claims (4)

[Claims] 1. An ink jet recording apparatus having a filter chamber provided with a filter having an increased flow path width in the middle of an ink supply flow path connected at one end to an ink supply container and at the other end to an ink jet recording head. An elastically deforming portion made of an elastic body is provided on a side wall of the filter chamber, and the inside of the ink supply flow path is depressurized from the recording head side so that the elastically deformable portion deforms inward to reduce the flow path. An ink jet recording apparatus characterized in that: 2. An ink jet recording apparatus having a filter chamber provided with a filter having an increased flow path width in the middle of an ink supply flow path connecting one end to an ink supply container and the other end to an ink jet recording head. , A separate elastic body is attached to the inner surface of the side wall of the filter chamber to form a double side wall, and the outer peripheral surface of the upstream end portion and the outer peripheral surface of the downstream end portion of the elastic body are separated by the filter. In the state in which the inside of the ink supply flow path is depressurized from the recording head side, an unfixed intermediate portion between the upstream end and the downstream end of the elastic body is inwardly fixed to the inner surface of the side wall of the chamber. An ink jet recording apparatus characterized in that it is configured to be deformed to reduce a flow path. 3. An ink supply needle inserted into an ink supply container at a distal end of the filter chamber, wherein a side wall of the filter chamber is formed in a tapered shape from the upstream end to the downstream filter. The ink jet recording apparatus according to claim 1, wherein the hollow shaft portion is integrally formed. 4. An air communication hole, which is provided at a part of a side wall of the filter chamber, for communicating an outer peripheral surface side of the separate elastic body to atmospheric pressure.
Or the inkjet recording apparatus according to 3.