JP2012101460A - Liquid ejecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejecting apparatus in which pressure fluctuation of a liquid generated on the upstream side of an ejecting head is prevented from being transmitted to an ejecting nozzle.SOLUTION: The liquid in a liquid container is taken in through a liquid take-in port, is supplied to the ejecting head through a liquid passage, and then, jetted from the ejecting nozzle. A filter chamber with a filter therein is provided in the liquid passage, and a connection port is provided upstream with respect to the filter arranged in the filter chamber. Then, air is supplied into the filter chamber through the connection port. In this manner, the air supplied into the filter chamber through the connection port is used as a damper for absorbing the pressure fluctuation in the liquid transmitted from the upstream side of the liquid passage, consequently, the transmission of pressure fluctuation in the liquid to the ejecting nozzle is suppressed.

Description

  The present invention relates to a technique for ejecting liquid from an ejection nozzle provided in an ejection head.

As represented by so-called ink jet printers, liquid ejecting apparatuses that eject liquid from fine ejecting nozzles provided in an ejecting head are known. In this liquid ejecting apparatus,
A liquid such as ink to be ejected is stored in a dedicated container such as an ink cartridge, and the liquid is ejected by supplying the liquid from the dedicated container to the ejection head via the liquid passage.

Such a cartridge is configured to be detachable from the liquid ejecting apparatus so that the cartridge is replaced with a new one when the liquid in the interior is exhausted (for example, Patent Document 1).
When the cartridge is mounted, a liquid take-up needle that communicates with the liquid passage is inserted into the liquid supply port of the cartridge, and the liquid in the cartridge is taken into the liquid passage.

JP 2007-216563 A

However, in the liquid ejecting apparatus employing such a cartridge system, there is a problem that a problem (so-called nozzle omission) may occur that the liquid is not ejected appropriately from the ejection nozzle immediately after the cartridge is replaced. This is because when the liquid intake needle is inserted into the liquid supply port of the cartridge, the pressure fluctuation (increase in pressure) occurs in the liquid as the volume of the liquid supply port changes (decreases). It originates in destroying the meniscus which the liquid surface has formed with the injection nozzle by transmitting to the injection nozzle through the liquid passage.

In addition, the pressure fluctuation of the liquid that occurs on the upstream side of such an ejection head is not only when the liquid intake needle is inserted into the liquid supply port, but also when touching the adjacent cartridge in the operation of replacing any of the plurality of cartridges, This also occurs when the relative position of the cartridge and the liquid take-in needle changes due to an impact when the liquid ejecting apparatus is dropped during movement. Furthermore, in a liquid ejecting apparatus of a type that supplies the liquid in the cartridge to the ejecting head through the liquid supply tube, if the liquid supplying tube shakes as the ejecting head moves relative to the cartridge, a so-called pumping effect is achieved. As a result, the pressure fluctuation of the liquid occurs in the liquid supply tube.

The present invention has been made to solve the above-described problems of the prior art,
It is an object of the present invention to provide a technique capable of suppressing the pressure fluctuation of the liquid generated on the upstream side of the ejection head from being transmitted to the ejection nozzle.

In order to solve at least a part of the problems described above, the liquid ejecting apparatus of the present invention employs the following configuration. That is, a liquid ejecting apparatus that supplies liquid contained in a liquid storage container to an ejection head and ejects the liquid from an ejection nozzle provided in the ejection head, and is a liquid that takes in the liquid in the liquid accommodation container An inlet, a liquid passage for guiding the liquid taken in from the liquid inlet to the ejection head, and a filter provided in the liquid passage for removing foreign matters in the liquid flowing in the liquid passage. The gist is provided with a filter chamber provided inside, and an air supply means for supplying air into the filter chamber from a connection port provided on the upstream side of the filter in the filter chamber.

In such a liquid ejecting apparatus of the present invention, the liquid to be ejected is accommodated in the liquid container, and the liquid taken in from the liquid intake port is supplied to the ejecting head through the liquid passage, It ejects from the ejection nozzle provided in the ejection head. The liquid passage is provided with a filter chamber having a filter therein, and foreign substances are removed when the liquid passes through the filter. In the liquid ejecting apparatus of the present invention, a connection port is provided on the upstream side of the filter in the filter chamber, and air can be supplied from the connection port into the filter chamber.

Here, as a configuration for supplying air into the filter chamber, for example, when the liquid in the filter chamber is drawn into the ejection head as the liquid is ejected from the ejection nozzle, the pressure in the filter chamber becomes negative. May comprise an on-off valve connected to the connection port, and open air may be introduced into the filter chamber by opening the on-off valve. Moreover, as a pump connected to the connection port is provided, air may be pumped into the filter chamber by the pump.

In the liquid ejecting apparatus of the present invention having the above-described configuration, the air supplied from the connection port to the filter chamber can be used as a damper that absorbs the pressure fluctuation of the liquid that occurs upstream from the filter chamber. That is, when the pressure fluctuation of the liquid is transmitted through the liquid passage and the pressure of the liquid in the filter chamber increases, the air (bubbles) in the filter chamber contracts, thereby suppressing a sudden pressure increase. Conversely, if the liquid pressure decreases, air (
The bubble) expands and functions to suppress a rapid pressure decrease. By incorporating air into the filter chamber in this way, it is possible to absorb (relax) the pressure fluctuations of the liquid transmitted from the upstream side of the liquid passage, so that the liquid can reach the injection nozzle provided in the downstream injection head. It is possible to suppress the transmission of the pressure fluctuation. As a result, it is possible to prevent a malfunction (nozzle omission) in which the liquid is not properly ejected from the ejection nozzle due to the pressure fluctuation of the liquid.

In addition, although air may enter the filter chamber due to air entering from the liquid intake or air bubbles that have been dissolved in the liquid, the amount of air may not be constant. When there is too little, it cannot fully absorb the pressure fluctuation of a liquid. Therefore, if air can be supplied from the connection port provided in the filter chamber, air can be intentionally supplied to the filter chamber, so that a sufficient amount of air to absorb the pressure fluctuation of the liquid is filtered. It can be secured indoors. as a result,
It can suppress more reliably that the pressure fluctuation of a liquid is transmitted to an injection nozzle.

Furthermore, in the liquid ejecting apparatus of the present invention, air is supplied to the upstream side of the filter in the filter chamber, so that it is possible to suppress the air from riding on the liquid flow and flowing to the downstream ejecting head. That is, if air is supplied downstream from the filter, the air flows downstream and is supplied to the ejection head, so that the liquid is not properly ejected from the ejection nozzle. On the other hand, if air is supplied to the upstream side of the filter, the air that has reached the filter on the liquid flow is captured by the filter and is prevented from flowing downstream, so the air flows to the ejection head. This can be suppressed.

In the liquid ejecting apparatus of the present invention described above, including a pump connected to the connection port,
Air in the filter chamber may be sucked by generating negative pressure with a pump.

The air in the filter chamber may increase when air enters from the liquid intake port or air that has been dissolved in the liquid is bubbled. Therefore, if the air in the filter chamber can be sucked from the connection port, if more than a predetermined amount of air (the amount necessary to absorb the liquid pressure fluctuation) is accumulated in the filter chamber, unnecessary air Therefore, the amount of air in the filter chamber can be kept appropriate. As a result, it is possible to reduce the possibility of air flowing to the downstream jet head.

In general, the air mixed in the liquid passage or the filter chamber is discharged together with a large amount of liquid by sucking from a spray nozzle (so-called cleaning operation) or the like. On the other hand, if the air is directly sucked from the connection port provided in the filter chamber, the air in the filter chamber can be discharged without wasting the liquid.

In the above-described liquid ejecting apparatus of the present invention, when the ejection of the liquid from the ejection nozzle is finished, air is supplied into the filter chamber, and when the ejection of the liquid from the ejection nozzle is started, the filter Indoor air may be sucked.

Thus, if the air is taken in and out of the filter chamber depending on whether or not the liquid is ejected from the ejection nozzle, the pressure fluctuation of the liquid is absorbed by the air for the following reasons, and the air It is possible to more effectively make the downstream jet head not flow. First, paying attention to the fact that the pressure fluctuation of the liquid that occurs upstream of the liquid passage occurs when the liquid storage container is replaced or when the liquid ejecting apparatus is dropped while moving, when the liquid is ejected In contrast, when the liquid is not ejected, the pressure fluctuation of the liquid is likely to occur.
Further, the flow of liquid in the liquid passage and in the filter chamber tends to be weaker when the liquid is not ejected than when the liquid is ejected. Therefore, when the liquid is not being ejected (when the pressure fluctuation of the liquid is likely to occur and the flow of the liquid in the liquid passage is weak), air is taken into the filter chamber to obtain a damper effect by the air. , It is possible to prevent the pressure fluctuation of the liquid from being transmitted to the injection nozzle. On the other hand, when the liquid is being ejected (when the liquid pressure hardly changes and the liquid flow in the liquid passage is strong), the air is removed from the filter chamber so that the air flows to the downstream ejecting head. The possibility of flowing can be made lower.

In the liquid ejecting apparatus of the present invention, the following may be performed. First, in the filter chamber, an air storage section is provided on the upstream side of the filter that accumulates when air mixed with the flow of liquid rises by buoyancy. And a connection port is provided in this air storage part.

In this way, when supplying air into the filter chamber, air can be supplied directly to a place where air accumulates (a place where it is difficult for air to flow) without placing the air on the liquid flow. Can be prevented from flowing to the downstream jet head. On the other hand, when the air in the filter chamber is sucked, air can be sucked easily from the location where the air is accumulated, so that the liquid discharged together with the air can be reduced.

Further, in the liquid ejecting apparatus of the present invention described above, the following may be performed. First, in the filter chamber, a widened portion whose cross-sectional area widens downward is provided, and a filter is provided at the lower end of the widened portion. And the position of the ceiling of the air storage part opened to the wall surface of a wide part is set to a position higher than the upper end of a wide part.

According to such a configuration, when the air moves on the flow of the liquid and moves to the widened portion, the flow of the liquid becomes slow in the widened portion, and thus the air that has been flown is lifted by buoyancy. At this time, the air that has floated enters the air storage portion that opens to the wall surface of the widened portion, so that air accumulates on the ceiling of the air storage portion. Since the ceiling of this air storage part is set at a position higher than the upper end of the widened part, the stagnation area where the vicinity of the ceiling of the air storage part deviates from the liquid flow (the liquid flow does not enter). It has become. Therefore, the air accumulated on the ceiling of the air reservoir does not ride on the liquid flow and flows to the downstream jet head, and the air can be stably accumulated in the air reservoir.

Furthermore, in the liquid ejecting apparatus of the present invention described above, a plurality of protrusions may be provided on the ceiling of the air storage unit, so that air that is lifted by buoyancy may be supported at a plurality of locations by point contact or line contact.

Since it is the contact surface between air and liquid that can directly absorb the pressure fluctuation of the liquid on the surface of air (bubbles), when absorbing the pressure fluctuation of the liquid using air, If the contact area of the liquid is increased, the pressure fluctuation of the liquid can be absorbed quickly. Therefore, if the air is supported at a plurality of locations by point contact or line contact by the plurality of protrusions provided on the ceiling of the air storage unit, the air directly contacts the surface of the air storage unit (surface contact). ) Compared to the case, a wide contact area between air and liquid can be ensured. As a result, the pressure fluctuation of the liquid transmitted from the upstream side of the liquid passage can be quickly absorbed by the air in the air reservoir.

It is explanatory drawing which showed the rough structure of the liquid ejecting apparatus of a present Example using an inkjet printer as an example. FIG. 6 is an explanatory diagram illustrating a state where an ink cartridge is mounted on a carriage case. FIG. 4 is a cross-sectional view illustrating a configuration of an ink supply port provided in the ink cartridge. It is explanatory drawing which showed the structure of the ink intake needle | hook of a present Example. It is the flowchart which showed the flow of the air management process performed with the inkjet printer of a present Example. It is explanatory drawing which showed the structure of the tube pump mounted in the inkjet printer of a present Example. It is sectional drawing which showed the structure of the air storage chamber of a 1st modification. It is explanatory drawing which showed the structure for taking in and out air to an air storage chamber with the inkjet printer of a 2nd modification. It is explanatory drawing which showed the structure of the inkjet printer of a 3rd modification. It is explanatory drawing which showed the example which provided the guide part eccentrically with respect to the wide part of the ink taking-in needle. It is explanatory drawing which showed the example which has arrange | positioned the air storage chamber provided in the wide part of an ink taking-in needle on both sides with respect to the guidance part.

Hereinafter, in order to clarify the contents of the present invention described above, examples will be described in the following order.
A. Device configuration:
A-1. Configuration of liquid ejector:
A-2. Ink take-up needle configuration:
B. Air management processing of this embodiment:
C. Variations:
C-1. First modification:
C-2. Second modification:
C-3. Third modification:

A. Device configuration :
A-1. Configuration of liquid ejector:
FIG. 1 is an explanatory diagram showing a rough configuration of a liquid ejecting apparatus according to the present embodiment, using a so-called ink jet printer as an example. As shown, inkjet printer 1
0 is a carriage 20 that forms ink dots on the printing paper 2 as a printing medium while reciprocating in the main scanning direction, a drive mechanism 30 that reciprocates the carriage 20, and a paper feed for the printing paper 2. It comprises a platen roller 40 and a maintenance mechanism 50 that performs maintenance so that printing can be performed normally. The carriage 20 has an ink cartridge 26 containing ink, and a carriage case 22 in which the ink cartridge 26 is mounted.
Or the ejection head 2 mounted on the bottom side of the carriage case 22 (the side facing the printing paper 2).
4 etc. are provided. The ejection head 24 is formed with a plurality of ejection nozzles that eject ink. The ink in the ink cartridge 26 is guided to the ejection head 24 and ejected from the ejection nozzle toward the printing paper 2 by an accurate amount. By doing so, an image or the like is printed.

In the ink jet printer 10 of this embodiment, it is possible to print a color image using four types of inks of cyan, magenta, yellow, and black. The mounted ejection head 24 is provided with an ejection nozzle for each type of ink. An ink cartridge 26 is also provided for each type of ink, and ink is supplied from the corresponding ink cartridge 26 to each ejection nozzle. In addition, the ink cartridge 26 includes a carriage case 22.
When the ink in the ink cartridge 26 runs out,
The ink cartridge 26 is replaced with a new one. The ink cartridge 26 of this embodiment corresponds to a “liquid container” of the present invention.

The drive mechanism 30 for reciprocating the carriage 20 includes a guide rail 38 extending in the main scanning direction, a timing belt 32 having a plurality of teeth formed therein, and a timing belt 32.
The drive pulley 34 meshes with the tooth profile of the above, the step motor 36 for driving the drive pulley 34, and the like. A part of the timing belt 32 is fixed to the carriage case 22, and the carriage case 22 can be moved along the guide rail 38 by driving the timing belt 32. Further, since the timing belt 32 and the drive pulley 34 are engaged with each other by a tooth shape, when the drive pulley 34 is driven by the step motor 36, the carriage case 22 can be moved with high accuracy according to the drive amount. .

The platen roller 40 that feeds the printing paper 2 is driven by a drive motor or a gear mechanism (not shown) and can feed the printing paper 2 by a predetermined amount in the sub-scanning direction.

The maintenance mechanism 50 is provided in a region called a home position outside the printing region, and includes a cap 52, a suction pump 54 provided at a position below the cap 52, and a waste liquid tank provided further below the cap 52. 56 or the like. The cap 52 is
It can be moved in the vertical direction by an elevating mechanism (not shown), and while the inkjet printer 10 is not printing an image or the like, the carriage 20 is moved to the home position and the cap 52 is raised. Then, the closed space is formed so that the cap 52 is pressed against the bottom surface side of the ejection head 24 and covers the ejection nozzle, so that the ink in the ejection head 24 can be prevented from drying. In addition, a suction pump 54 is connected to the cap 52 via a suction tube (not shown). By operating the suction pump 54 with the cap 52 pressed against the bottom surface of the ejection head 24, the ejection head 24 is operated. It is also possible to suck out deteriorated ink (such as dried and thickened ink) and discharge it to the waste liquid tank 56 (so-called cleaning).

Furthermore, a control unit 60 that controls the entire operation of the inkjet printer 10 is mounted on the back side of the inkjet printer 10. The operation of reciprocating the carriage 20, the operation of feeding the printing paper 2, the operation of ejecting ink from the ejection nozzles, the operation of driving the maintenance mechanism 50 to enable normal printing, etc. are all performed by the control unit 60. Is controlled by.

FIG. 2 is an explanatory view showing a state in which the ink cartridge 26 is mounted on the carriage case 22. As shown in the drawing, the carriage case 22 is provided with a recess 23 for mounting the ink cartridge 26 from above, and the bottom surface of the recess 23 receives ink for taking ink from the ink cartridge 26. The insertion needle 100 is erected for each ink cartridge 26. An ink supply port 70 is provided at the bottom of the ink cartridge 26.
When the ink cartridge 26 is mounted on the carriage case 22,
The ink supply port 70 provided in the ink cartridge 26 is fitted to the position of the ink take-in needle 100 provided in the carriage case 22 so as to push the ink cartridge 26 downward. Then, the ink take-in needle 100 is inserted into the ink supply port 70, and the ink in the ink cartridge 26 can be taken into the ink take-in needle 100.

FIG. 3 is a cross-sectional view showing the configuration of the ink supply port 70 provided in the ink cartridge 26. FIG. 3 shows a state where the ink take-in needle 100 is inserted into the ink supply port 70. As shown in the drawing, the ink supply port 70 includes a sealing valve 74 and a sealing valve 74.
A spring 76 or the like that presses the ink toward the opening side (the lower side in the drawing) of the ink supply port 70 is provided. When the ink intake needle 100 is not inserted into the ink supply port 70, the sealing valve 74 is pushed down by the force of the spring 76 and the opening of the ink supply port 70 is closed. When the ink take-in needle 100 is inserted into the ink supply port 70, the tip of the ink take-in needle 100 pushes up the sealing valve 74 against the force of the spring 76, as shown in FIG. , The opening of the ink supply port 70 is opened, and the inserted ink take-in needle 100
Ink is taken into the ink take-in needle 100 through an ink take-in port 102 provided near the tip of the ink take-in.

A rubber seal member 72 is provided along the inner wall of the opening of the ink supply port 70. When the ink take-in needle 100 is inserted into the ink supply port 70, the seal member 72 is provided.
Is in close contact with the outer surface of the ink take-in needle 100 to prevent ink from leaking out.

Here, when the ink cartridge 26 is mounted on the carriage case 22, the volume of the ink supply port 70 changes (decreases) because the ink intake needle 100 is inserted into the ink supply port 70 as described above. Accordingly, pressure fluctuation (increase in pressure) occurs in the ink in the ink supply port 70. Such pressure fluctuation is not only caused when the ink cartridge 26 is mounted on the carriage case 22, but also when the ink cartridge 26 is replaced, the adjacent ink cartridge 26 is touched, or the inkjet printer 10 is dropped while moving. This also occurs when the relative position of the ink cartridge 26 and the carriage case 22 changes due to the impact. When such pressure fluctuation is transmitted to the ejection nozzle of the ejection head 24 through the ink intake needle 100, the meniscus formed on the ink surface of the ejection nozzle is destroyed, and as a result, the ink is appropriately ejected from the ejection nozzle. Unsatisfactory printing (so-called nozzle missing) occurs. Therefore, in the ink jet printer 10 of the present embodiment, the ink intake needle 100 having the following configuration is employed in order to suppress the pressure fluctuation of the ink from being transmitted to the ejection nozzle.

A-2. Ink take-up needle configuration:
FIG. 4 is an explanatory diagram showing the configuration of the ink take-in needle 100 of the present embodiment. First, FIG.
) Is a perspective view showing an appearance of the ink take-in needle 100. As shown in the drawing, the ink take-in needle 100 has an upper step portion formed in a cylindrical shape and a lower step portion formed in a conical shape, and ink is applied to a pointed tip of the upper step portion. Multiple ink inlets 10 to be taken in
2 is open. In addition, an air storage chamber 112 protrudes from the lower stage portion. As will be described in detail later, air (bubbles) mixed in the ink take-in needle 100 can be stored in the air storage chamber 112. It is possible.

FIG. 4B is a cross-sectional view of the ink take-in needle 100 taken along a vertical plane passing through the tip of the ink take-up needle 100 and the center of the air storage chamber 112. As shown in the drawing, an inflow passage 1 into which ink taken in from the ink take-in port 102 flows into the ink take-in needle 100.
04 is provided, and a filter 110 for removing foreign substances contained in the ink is provided at the downstream end of the inflow passage 104. The inflow passage 104 includes a guide portion 106 whose cross-sectional area does not change and a widened portion 108 whose cross-sectional area widens toward the downstream side (downward in the drawing). The filter 110 is made of fine particles so as to remove foreign substances that clog the injection nozzle and the fine passage to the injection nozzle, so that the filter 110 makes it difficult for ink to flow (the flow resistance is reduced). However, the flow rate of ink passing through the filter 110 can be ensured by providing the widened portion 108 to widen the cross-sectional area. The ink that has passed through the filter 110 passes through the carriage case 22.
It is supplied to the ejection head 24 through a supply passage 28 provided in the inside. The ink intake port 102 of this embodiment corresponds to the “liquid intake port” of the present invention, and the inflow passage of this embodiment that guides the ink taken from the ink intake port 102 to the ejection head 24. 104 and supply passage 2
Reference numeral 8 corresponds to the “liquid passage” of the present invention. In addition, the widened portion 108 of the present embodiment in which the filter 110 is provided at the downstream end corresponds to the “filter chamber” of the present invention.

Furthermore, as described above, the ink intake needle 100 of the present embodiment is provided with the air storage chamber 112 for storing the air (bubbles) mixed in the inflow passage 104. As shown in the drawing, the air storage chamber 112 has a bottom portion that opens to the wall surface of the widened portion 108, and
The ceiling (the surface constituting the upper end side of the air storage chamber 112) is set at a position higher than the upper end of the widened portion 108. The air storage chamber 112 of this embodiment corresponds to the “air storage section” of the present invention.

Mixing of air into the inflow passage 104 occurs when air enters from the ink intake port 102 when the ink intake needle 100 is inserted into the ink supply port 70 or air that has been dissolved in the ink is bubbled. To do. The air in the inflow passage 104 moves on the ink flow and moves to the widened portion 108 on the downstream side. Since the ink flow is slow in the widened portion 108, the air that has been flown rises due to buoyancy. At this time, the air that has been lifted up is the widened portion 10.
By entering the air storage chamber 112 that opens to the wall surface 8, air accumulates on the ceiling of the air storage chamber 112. Further, since the ceiling of the air storage chamber 112 is provided so as to be higher than the upper end of the widened portion 108, it is a stagnation region that deviates from the ink flow (streamline). Therefore, the air accumulated on the ceiling of the air storage chamber 112 does not get on the ink flow, and the outflow of air from the air storage chamber 112 can be suppressed.

As described above, in the inkjet printer 10 of the present embodiment, the air storage chamber 112 is provided in the widened portion 108 of the inflow passage 104, and the air stored in the air storage chamber 112 is stored in the air storage chamber 112. Since it functions as a damper, it is possible to suppress the ink pressure fluctuation generated upstream of the inflow passage 104 from being transmitted to the ejection nozzle. That is, when the ink pressure fluctuation is transmitted through the inflow passage 104 and the ink pressure in the widened portion 108 and the air storage chamber 112 is increased, the air (bubbles) in the air storage chamber 112 is contracted. When the ink pressure in the widened portion 108 decreases, the air in the air storage chamber 112 expands to suppress the pressure decrease. In this way, the air in the air storage chamber 112 can be used as a damper to absorb (relax) the pressure fluctuation of the ink transmitted from the upstream side of the inflow passage 104 to the widened portion 108, so that the downstream jet nozzle It is possible to suppress the transmission of the ink pressure fluctuations.

Note that the more air in the air storage chamber 112 (the larger the bubbles), the larger the pressure fluctuation can be absorbed (Boil's law). However, as described above, the ink take-in needle 100 is mounted on the carriage case 22, and the air storage chamber 1 for storing air.
The 12 volume is also limited. The meniscus formed on the ink surface of the ejection nozzle tends to be destroyed when a pressure of about 4 kPa or more is applied. Therefore, if the ink pressure fluctuation is made smaller than this, nozzle omission can be prevented. As an example, the ink take-in needle 100 with a volume of 77 mm ³
On the other hand, if air of 16 mm ³ or more is stored, the experimental result has been obtained that the ink pressure fluctuation generated when the ink cartridge 26 is attached to the carriage case 22 can be absorbed, and the nozzle omission can be prevented. . Therefore, in this case, an air storage chamber 112 that can store air of about 16 mm ³ may be provided.

Here, since the amount of air entering from the ink intake port 102 when the ink intake needle 100 is inserted into the ink supply port 70 and the amount of air that has melted into the ink bubbled are not constant, the air storage chamber If there is too little air (bubbles) accumulated in 112, ink pressure fluctuations may not be fully absorbed. Conversely, when there are too many air (bubbles), the air that has flowed out of the air storage chamber 112 flows downstream and is supplied to the ejection head 24, so that ink is ejected appropriately from the ejection nozzles. It will disappear.

In view of these points, in the inkjet printer 10 of the present embodiment, the air storage chamber 112 is used.
A connection port 114 is provided on the ceiling of the air supply port. Air can be supplied from the connection port 114 to the air storage chamber 112, and air in the air storage chamber 112 can be sucked. As will be described in detail later, in the inkjet printer 10 of the present embodiment, a tube pump is connected to the connection port 114 via a connection tube 116, and air is supplied to the air storage chamber 112 by driving the tube pump. It can be put in and out. Moreover, in the inkjet printer 10 of a present Example, the air management process as follows is performed and the air in the air storage chamber 112 is managed.

B. Air management processing of this embodiment:
FIG. 5 is a flowchart showing the flow of air management processing performed by the inkjet printer 10 of the present embodiment. This process is executed by the control unit 60 when the power of the inkjet printer 10 is turned on.

As shown in the drawing, in the air management process, first, the ink jet printer 10 is used.
Determines whether to start printing (step S100). As described above, the control unit 60
Since the overall operation of the inkjet printer 10 is controlled, the timing for starting printing can be determined. As described above, when printing is not being performed, the carriage 20 is at the home position, and printing is started by moving the carriage 20 to the printing area. Therefore, when the carriage 20 is moved to the printing area, printing is performed. May be determined to start. If printing is not started (step S100: no), the determination of step S100 is repeated to monitor the start of printing.

On the other hand, when printing is started (step S100: yes), the tube pump connected to the connection port 114 of the air storage chamber 112 via the connection tube 116 is driven in the suction direction, so that the inside of the air storage chamber 112 is Air (bubbles) is sucked (step S102). As described above, the ink pressure fluctuation generated on the upstream side of the inflow passage 104 is caused by the ink cartridge 26.
This is likely to occur when printing is not performed, such as when the printer is replaced or when the inkjet printer 10 is dropped during movement. In other words, since the ink pressure fluctuation is less likely to occur during printing, it is less necessary to store air in the air storage chamber 112 to absorb the ink pressure fluctuation than when printing is not performed. . In the unlikely event that air flows downstream and is supplied to the ejection head 24 during printing, ink will not be ejected properly from the ejection nozzles, resulting in printing defects. Therefore, in the ink jet printer 10 of the present embodiment, when the printing is started, the air in the air storage chamber 112 is sucked and discharged.

Here, the structure of the tube pump of the present embodiment connected to the connection port 114 of the air storage chamber 112 will be briefly described. FIG. 6 is an explanatory view showing the structure of the tube pump 150 mounted on the ink jet printer 10 of this embodiment. As shown in the figure, in the tube pump 150, a part of the tube 154 connected to the connection tube 116 is accommodated in an arc shape along the inner wall of the housing 152 in a cylindrical housing 152. It has a structure. In addition, a rotating disk 156 is provided inside the housing 152, and a roller 158 is rotatably supported by the rotating disk 156 in the guide groove 160. The guide groove 160 is close to the outer periphery of the rotating disk 156 on one end side,
The other end is formed so as to be away from the outer periphery of the rotating disk 156.

The tube pump 150 having such a structure operates as follows. First, when a motor (not shown) is operated to rotate the rotating disk 156 in the suction direction (the direction indicated by the arrow in the drawing), the roller 158 moves to one end side of the guide groove 160 and is shown in FIG. As described above, the tube 154 is squeezed (closed) between the roller 158 and the inner wall of the housing 152 because it protrudes greatly from the outer periphery of the rotating disk 156. In this state, when the rotating disk 156 is rotated in the suction direction and the roller 158 is moved along the tube 154,
Since the closed portion of the tube 154 also moves, the fluid (air, ink, etc.) in the tube 154 is sequentially pushed out and transferred downstream. In addition, after the roller 158 passes, the closed portion of the tube 154 tries to return to its original shape by the restoring force of the tube, so that a negative pressure is generated in the tube 154 and the fluid is sucked from the upstream. be able to. On the other hand, when the rotating disk 156 is rotated in the release direction (the direction opposite to the suction direction), the roller 1
Since 58 moves to the other end side of the guide groove 160 and moves away from the outer periphery of the rotating disk 156, the tube 154 is released from the closed state and is in an open state (communication state).

In step S102 of the air management process shown in FIG. 5, the tube pump 150 is driven in the suction direction to make the connection tube 116 have a negative pressure, whereby the air in the air storage chamber 112 is sucked (extracted). Can do. In the inkjet printer 10 of the present embodiment, an air detection sensor (not shown) for detecting the air in the air storage chamber 112 is provided, and the tube pump 150 is stopped when the air in the air storage chamber 112 is discharged. (Step S104). In this embodiment, air discharge is detected using an air detection sensor. However, the present invention is not limited to this. For discharging the fluid (air and ink) corresponding to the volume of the air storage chamber 112. The required time (discharge time) may be obtained in advance, and the tube pump 150 may be stopped when the discharge time has elapsed. In this case, the air in the air storage chamber 112 is discharged together with the surrounding ink.

When the air in the air storage chamber 112 is discharged in this way, it is then determined whether or not to end printing (step S106). The control unit 60 that controls the overall operation of the ink jet printer 10 can determine the timing for ending printing, as with the start of printing.
As described above, since the carriage 20 is moved to the home position when printing is not performed, it may be determined that the printing is finished when the carriage 20 is moved to the home position. If printing is still in progress (step S106:
no), the determination in step S106 is repeated, and the end of printing is monitored.

On the other hand, when the printing is finished (step S106: yes), the tube pump 150 is driven in the release direction to be in an open state (step S108). As previously mentioned,
When printing is not being performed, ink pressure fluctuations may occur on the upstream side of the inflow passage 104 due to replacement of the ink cartridge 26 or dropping when the inkjet printer 10 is moved. 10, air for absorbing such pressure fluctuations of ink is stored in the air storage chamber 112 when printing is finished. As described above with reference to FIG. 6, when the tube pump 150 is driven in the release direction, the blockage of the tube 154 in the tube pump 150 is released.
The air storage chamber 112 is opened to the atmosphere. During printing, as ink is ejected from the ejection nozzles of the ejection head 24, the ejected ink is drawn into the ejection head 24, so negative pressure is generated in the inflow passage 104 and in the air storage chamber 112. It has become. Therefore, air is introduced into the air storage chamber 112 by opening the tube pump 150 when printing is finished.

In the inkjet printer 10 of the present embodiment, when supplying air to the air storage chamber 112, the tube pump 150 is driven in the release direction. However, the present invention is not limited to this. For example, the connection port 114 is used. Instead of driving the tube pump 150 in the release direction, by opening the on-off valve,
Air may be supplied to the air storage chamber.

Then, when a predetermined amount of air for absorbing ink pressure fluctuations is taken into the air storage chamber 112, the tube pump 150 is driven in the suction direction to close the tube 154 (step S110). ). In the present embodiment, the air detection sensor detects that the air in the air storage chamber 112 has reached a predetermined amount and closes the tube pump 150. However, the present invention is not limited to this, and the air storage chamber 112 is not limited thereto. The time required for taking in a predetermined amount of air (take-in time) may be obtained in advance, and the tube pump 150 may be closed when the take-in time has elapsed.

When a predetermined amount of air is thus taken into the air storage chamber 112, the process returns to the top of the air management process and waits until printing is started again (step S100). When printing is started, the tube pump 150 is moved in the suction direction. To suck the air in the air storage chamber 112 (step S102).

As described above, in the ink jet printer 10 of this embodiment, the air storage chamber 112 is provided in the ink intake needle 100 so as to communicate with the inflow passage 104. The air storage chamber 112 is provided at a position above the widened portion 108 of the inflow passage 104 with the bottom portion opened to the wall surface of the widened portion 108. Since the ink flow is slow in the widened portion 108, the widened portion 1
The air that has flowed up to 08 is lifted by buoyancy, and at this time, the air that has floated enters the air storage chamber 112, so that the air accumulates on the ceiling of the air storage chamber 112. The air thus stored in the air storage chamber 112 functions as a damper that absorbs the ink pressure fluctuation generated on the upstream side of the inflow passage 104, so that the ink pressure fluctuation is transmitted to the ejection nozzles of the downstream ejection head 24. Can be suppressed.

Although such air (bubbles) is effective in absorbing ink pressure fluctuations, if it flows downstream and is supplied to the ejection head 24, the ink is not properly ejected from the ejection nozzles, resulting in poor printing. Will occur. In the inkjet printer 10 of the present embodiment, the ceiling of the air storage chamber 112 is set at a position higher than the upper end of the widened portion 108.
The upper part (near the ceiling) of the air storage chamber 112 is a stagnation region where the flow of ink does not enter. For this reason, the air accumulated on the ceiling of the air storage chamber 112 does not move on the ink flow, and the air can be prevented from flowing to the downstream ejection head 24.

In addition, in the inkjet printer 10 of the present embodiment, the connection port 114 is provided in the ceiling of the air storage chamber 112, and air can be supplied (taken in) from the connection port 114 to the air storage chamber 112. ing. Thereby, a sufficient damper effect due to the air (bubbles) in the air storage chamber 112 can be obtained, so that the pressure fluctuation of the ink generated on the upstream side of the inflow passage 104 can be transmitted to the ejection nozzle more reliably. Can be suppressed.
That is, the ink intake port 102 of the ink intake needle 100 when the ink cartridge 26 is replaced.
From the air, or the air that has been dissolved in the ink is bubbled, so that the inflow passage 1
Although air is mixed in 04, the amount is not constant, and if the amount of air is too small, ink pressure fluctuations may not be sufficiently absorbed. Therefore, if air can be supplied from the connection port 114 provided in the air storage chamber 112, it is possible to secure an amount of air that can absorb ink pressure fluctuation by actively supplying air. As a result, it is possible to more reliably suppress the ink pressure fluctuation from being transmitted to the ejection nozzle.

In the inkjet printer 10 of the present embodiment, the air in the air storage chamber 112 can be sucked (extracted) from the connection port 114 provided in the air storage chamber 112. For this reason, when air of a predetermined amount (an amount necessary for obtaining a damper effect) or more is mixed in the inflow passage 104, air is sucked from the connection port 114 of the air storage chamber 112,
The air in the air storage chamber 112 can be maintained at an appropriate amount, and as a result, the possibility that the air flows to the downstream jet head 24 can be reduced. In addition, the connection port 1 of the air storage chamber 112
If air can be discharged from 14, unlike the case where air is discharged from the ejection nozzle together with a large amount of ink by performing the above-described cleaning operation, the ink is not wasted.
Air can be discharged.

Furthermore, in the inkjet printer 10 of the present embodiment, paying attention to the fact that ink pressure fluctuations that occur on the upstream side of the inflow passage 104 are more likely to occur when printing is not performed than when printing, whether or not printing is in progress. Accordingly, air is taken in and out of the air storage chamber 112. Thus, when printing is not being performed, air is stored in the air storage chamber 112, so that an air damper effect can be obtained. Therefore, it is possible to suppress the ink pressure fluctuation from being transmitted to the ejection nozzle. On the other hand, during printing in which ink pressure fluctuations are less likely to occur than when printing is not performed, the possibility of air flowing to the downstream ejection head 24 is further reduced by extracting the air in the air storage chamber 112. be able to.

C. Modified example:
There are several variations of the inkjet printer 10 of the present embodiment described above. Hereinafter, these modified examples will be described. In the description of the modification,
Constituent parts similar to those of the above-described embodiment are denoted by the same reference numerals as those of the above-described embodiment,
Detailed description thereof is omitted.

C-1. First modification:
As described above, when the ink pressure fluctuation is absorbed using the air stored in the air storage chamber 112, if the contact area between the air and the ink is widened, the ink pressure fluctuation can be quickly absorbed. . Therefore, in the ink jet printer 10 of the first modified example, an air storage chamber 112 having the following configuration is employed in order to increase the contact area between air and ink.

FIG. 7 is a cross-sectional view showing the configuration of the air storage chamber 112 of the first modification. As shown in FIG. 7A, a plurality of ribs 118 project from the ceiling of the air storage chamber 112 of the first modification. When the air (bubbles) in the air storage chamber 112 is lifted by buoyancy, it is supported at a plurality of locations by line contact with the tip of the rib 118, so that the rib 118 is not provided on the ceiling of the air storage chamber 112. Thus, the area where the air contacts the ceiling of the air storage chamber 112 can be reduced.

FIG. 7B shows a state in which air is stored in the air storage chamber 112 where the rib 118 is not provided for comparison. In this case, the air that has floated directly comes into contact (surface contact) with the ceiling of the air storage chamber 112. Therefore, the portion that can absorb ink pressure fluctuation on the air surface is limited to the portion not in contact with the ceiling of the air storage chamber 112, that is, the lower portion in contact with the ink. Note that the arrows in FIG. 7 schematically show how air absorbs the ink pressure increase.

On the other hand, as shown in FIG. 7A, the air is supported by the tips of the plurality of ribs 118,
If the area where the air is in contact with the ceiling of the air storage chamber 112 is made small, the contact area between the air and the ink is secured to that extent, so that the ink pressure fluctuation is not only on the lower side but also on the upper side. Absorbable. As a result, a rapid ink pressure fluctuation can be quickly absorbed by the air in the air storage chamber 112.

In the first modification described above, a plurality of ribs 118 are provided on the ceiling of the air storage chamber 112,
Although air is supported at a plurality of locations by line contact, a plurality of small protrusions may be provided instead of the ribs 118 to support air at a plurality of locations by point contact. As described above, when the air is supported by point contact, it is possible to ensure a wide contact area between the air and the ink as compared with the case of surface contact.

C-2. Second modification:
In the above-described embodiment, air is taken into and out of the air storage chamber 112 by the tube pump 150.
It was supposed to be done using. However, the configuration for taking air in and out is not limited to this. Below, the 2nd modification which carries out the taking-in / out of air with respect to the air storage chamber 112 by the structure different from the Example mentioned above is demonstrated.

FIG. 8 is an explanatory diagram showing a configuration for taking air into and out of the air storage chamber 112 by the ink jet printer 10 of the second modified example. As illustrated, in the inkjet printer 10 of the second modification, the connection port 1 of the air storage chamber 112 is connected via the connection tube 116.
14 is connected to a cylinder 170. A piston 172 is provided in the cylinder 170 so as to be able to reciprocate. The piston 172 is connected to an actuator (not shown) via a connecting rod 174.

According to such a configuration, when the actuator is operated to move the piston 172 to the air storage chamber 112 side (left side in the figure), the air in the cylinder 170 is pumped and supplied to the air storage chamber 112. Can do. On the other hand, when the actuator is operated in the reverse direction and the piston 172 is moved to the actuator side (right side in the figure), the cylinder 170 becomes negative pressure, so the air in the air storage chamber 112 is sucked (extracted). Can do.

As described above, also in the ink jet printer 10 of the second modified example, the air storage chamber 1
By reciprocating the piston 172 in the cylinder 170 connected to the twelve connection ports 114, air can be taken in and out of the air storage chamber 112 as in the above-described embodiment. Therefore, by actively supplying air to the air storage chamber 112, it is possible to secure an amount of air that can absorb ink pressure fluctuations. In addition, when there is too much air in the air storage chamber 112 or when it is less necessary to store air, the air in the air storage chamber 112 is sucked (extracted), so that the air is sent to the jet head 24 downstream. Flow can be suppressed.

C-3. Third modification:
In the above-described embodiment, air is taken in and out of the air storage chamber 112 depending on whether printing is in progress. However, since the pressure variation of the ink may occur on the upstream side of the ejection head 24 during printing, the air may be stored without being extracted from the air storage chamber 112 during printing. .

FIG. 9 is an explanatory diagram showing the configuration of the ink jet printer 10 of the third modification. First, FIG. 9A shows a rough internal structure of the inkjet printer 10. In the embodiment described above, the ink cartridge 26 is mounted on the carriage 20 (see FIG. 1). However, as shown in FIG. 9A, in the inkjet printer 10 of the third modified example, the carriage 20 The ink cartridge 26 is mounted on a cartridge holder 80 provided at a different position, and the ink taken into the cartridge holder 80 from the ink cartridge 26 is supplied to the ejection head 24 of the carriage 20 via the supply tube 82. It has become.

As described above, in the inkjet printer 10 in which the ink cartridge 26 is mounted at a position different from the carriage 20, the supply tube 82 is shaken as the carriage 20 reciprocates along the guide rail 38 during printing. The so-called pumping effect causes ink pressure fluctuations in the supply tube 82. When such pressure fluctuations are transmitted to the ejection nozzles of the ejection head 24, the amount of ejected ink is affected, and printing defects may occur. In the ink jet printer 10 of the third modified example, a carriage 20 having the following configuration is employed in order to suppress the ink pressure fluctuation from being transmitted to the ejection nozzle.

FIG. 9B shows the configuration of the carriage 20 mounted on the ink jet printer 10 of the third modified example. As shown in the figure, a filter chamber 84 having a filter 86 for removing foreign matters contained in the ink is provided inside the carriage 20. A supply tube 82 is connected to the side surface of the filter chamber 84, and the ink flowing into the filter chamber 84 passes through the filter 86 and then ejects through the supply passage 28 connected to the bottom of the filter chamber 84. It is supplied to the head 24.

In addition, the bottom of the air storage chamber 112 is open on the upper surface of the filter chamber 84. The air that has entered the filter chamber 84 along with the flow of the liquid reaches the upper surface of the filter chamber 84 by being lifted by buoyancy. Since the upper surface of the filter chamber 84 is inclined upward toward the air storage chamber 112, the air that has been lifted by buoyancy accumulates on the ceiling of the air storage chamber 112. The air storage chamber 112 of the third modified example is also connected to the connection port 1 in the same manner as the above-described embodiment.
14 is provided, and the tube pump 150 is connected via the connection tube 116, so that air can be taken in and out of the air storage chamber 112 by driving the tube pump 150.

In the ink jet printer 10 according to the third modified example, as described above, the supply tube 82 is shaken along with the reciprocating movement of the carriage 20 during printing, thereby causing ink pressure fluctuations. Therefore, if air is left without being extracted from the air storage chamber 112 during printing, an air damper effect is obtained, and the ink pressure fluctuation is prevented from being transmitted to the ejection nozzle. Printing failure can be prevented. Also in this case, when the air in the air storage chamber 112 is small, by supplying air from the connection port 114 of the air storage chamber 112, it is possible to secure an amount of air that can absorb the pressure variation of the ink.
In addition, the air in the air storage chamber 112 may gradually increase due to air bubbles that are dissolved in the ink. Therefore, when air of a predetermined amount or more is accumulated in the air storage chamber 112, the amount of air in the air storage chamber 112 is reduced by sucking (extracting) air in the air storage chamber 112 from the connection port 114. As a result, air can be prevented from flowing to the downstream jet head 24.

Although various embodiments have been described above, the present invention is not limited to all the above embodiments, and can be implemented in various modes without departing from the scope of the invention.

For example, the guide portion 106 of the ink take-in needle 100 may be provided eccentrically instead of the center of the widened portion 108. FIG. 10 is an explanatory view showing the ink take-in needle 100 in which the guide portion 106 is eccentrically provided with respect to the widened portion 108. FIG. 10A shows a plan view of the ink take-in needle 100. The hatched portion in FIG. 10A is the air storage chamber 112.
The upper surface of is represented. FIG. 10B shows a cross-sectional view of the ink intake needle 100 cut along a vertical plane passing through the tip of the ink intake needle 100 and the center of the air storage chamber 112. In the example shown in FIG. 10, the widened portion 108 is formed in an oval shape (oval shape) instead of a perfect circular cone shape, and the guide portion 106 is provided eccentric to the widened portion 108 in the longitudinal direction. It has been. In this way, the air storage chamber 11 is located on the side opposite to the side on which the guide portion 106 is eccentric.
By providing 2, the space of the air storage chamber 112 can be secured widely, so that it is possible to store more air. As a result, it is possible to more reliably suppress the ink pressure fluctuation from being transmitted to the ejection nozzle.

The air storage chamber 112 provided in the widened portion 108 of the ink take-in needle 100 is provided with
However, it is not limited to one side, and may be provided on both sides as shown in FIG. In this case, the upper portions of the two air storage chambers 112 may be connected by the connecting passage 120. As described above, if the air storage chambers 112 are dispersed, it is possible to easily enter the air storage chamber 112 when the air that has moved on the ink flow and moved to the widening portion 108 is lifted by buoyancy.

10 ... inkjet printer, 20 ... carriage,
22 ... Carriage case, 24 ... Ejecting head, 26 ... Ink cartridge,
70 ... Ink supply port, 100 ... Ink intake needle, 102 ... Ink intake port,
104: Inflow passage, 106: Guide part, 108: Widening part,
110 ... Filter, 112 ... Air storage chamber, 114 ... Connection port,
116 ... Connection tube, 150 ... Tube pump

Claims (4)

A liquid ejecting apparatus that ejects the liquid from an ejecting nozzle provided in the ejecting head by supplying the liquid accommodated in the liquid container to the ejecting head,
A liquid inlet for taking in the liquid in the liquid container;
A liquid passage for guiding the liquid taken in from the liquid intake to the ejection head;
A filter chamber provided in the liquid passage and provided with a filter for removing foreign substances in the liquid flowing through the liquid passage;
A liquid ejecting apparatus comprising: an air supply means for supplying air into the filter chamber from a connection port provided upstream of the filter in the filter chamber. The liquid ejecting apparatus according to claim 1,
The liquid ejecting apparatus according to claim 1, wherein the air supply means includes a pump connected to the connection port, and is capable of sucking air in the filter chamber by generating a negative pressure with the pump. The liquid ejecting apparatus according to claim 2,
The air supply means includes
When the ejection of the liquid from the ejection nozzle is completed, air is supplied into the filter chamber,
A liquid ejecting apparatus which is means for sucking air in the filter chamber when the ejection of the liquid from the ejection nozzle is started. The liquid ejecting apparatus according to any one of claims 1 to 3,
In the filter chamber, an air reservoir that accumulates by buoyancy of air mixed in the filter chamber riding on the liquid flow is provided on the upstream side of the filter,
The connection port is a liquid ejecting apparatus provided in the air reservoir.

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