JP5902377B2 - Liquid ejector - Google Patents

Description

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

A so-called inkjet printer can print a high-quality image by ejecting an accurate amount of ink to a precise position from a fine ejection nozzle. In addition, by utilizing this technique and ejecting various liquids instead of ink toward the substrate, it is also possible to manufacture electrodes, sensors, biochips, and the like.

In such a technique, a liquid such as ink is ejected by using an ejection head having an ejection nozzle. When the liquid in the ejection head has deteriorated in properties, such as by increasing the viscosity, pressure cleaning, which is an operation of pushing out the liquid in the ejection head from the upstream side and discharging it to the cap, is performed. Sometimes it is.

Also, in the ejection head and in the passage for supplying the liquid to the ejection head, air dissolved in the liquid may be dissolved and bubbles may be generated, or bubbles may be generated by entraining external air. is there. When the bubbles thus generated block the ejection nozzle and the flow path, the liquid cannot be ejected well, and the print image quality is deteriorated. Therefore, a sub tank for temporarily storing the liquid is provided in the flow path for supplying the liquid to the ejection head, and the liquid and bubbles are circulated in the sub tank by circulating the liquid between the sub tank and the ejection head. Has been proposed (Patent Document 1).

JP 2008-246843 A

However, if a liquid pressurizing mechanism for performing pressure cleaning and a sub tank for separating bubbles are provided in the liquid ejecting apparatus, there is a problem that the entire apparatus becomes large.

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 an increase in size of a liquid ejecting apparatus while performing pressure cleaning and separation of bubbles in a liquid.

A liquid ejecting apparatus according to an embodiment of the present invention is a liquid ejecting apparatus that ejects liquid from an ejecting nozzle provided in an ejecting head, and is provided on the upstream side of the ejecting head in the liquid circulation direction. A liquid is stored between the first liquid storage unit configured to be able to discharge air bubbles mixed in the liquid to the atmosphere, and between the first liquid storage unit and the ejection head in the circulation direction of the liquid. A second liquid storage unit that is located and stores the liquid in a sealed state; and a backflow prevention unit that prevents the liquid from flowing back from the second liquid storage unit to the first liquid storage unit. A liquid storage tank provided in the first liquid storage section, a liquid passage for supplying the liquid from the second liquid storage section to the ejection head, and the liquid in the ejection head by sucking out the liquid in the ejection head. Liquid recirculation means for recirculating the liquid, and liquid pumping means for pressure-feeding the liquid to the ejection head by pressurizing the liquid in the second liquid storage section, and the second liquid storage section includes the second liquid storage section. A first opening that is open at the bottom of the liquid reservoir and communicates with the liquid passage; and a position upstream of the first opening in the direction of circulation of the liquid, and is provided upright from the bottom, and the second liquid And a shielding member capable of preventing the sediment precipitated in the storage portion from flowing into the opening.
In the liquid ejecting apparatus according to the embodiment of the invention, the liquid reflux unit is located between the first liquid storage unit and the liquid ejecting head in the liquid circulation direction.
In the liquid ejecting apparatus according to an embodiment of the invention, the liquid pumping unit is connected to the plate via a plate disposed horizontally in the second liquid storage unit and a connecting member. A drive mechanism capable of moving the plate up and down, generating a negative pressure in the second liquid reservoir by pulling the plate upward, and pulling the plate downward in the second liquid reservoir The liquid can be pressurized.
Further, in the liquid ejecting apparatus according to an embodiment of the present invention, a second opening is provided above the first liquid reservoir, and the pump is connected to the second opening via a passage; A separation plate that is provided in the first liquid storage portion and is located below the second opening and allows gas to pass therethrough, and by driving the pump, bubbles on the lower surface side of the separation plate are removed. It is possible to remove air bubbles from the first liquid reservoir by allowing the separation plate to pass through to the upper surface side.
In the liquid ejecting apparatus according to an embodiment of the invention, the shielding member is a member having a distal end bent in an opposite direction with respect to the first opening.
A liquid ejecting apparatus according to an embodiment of the invention includes an ejecting head that ejects liquid from an ejecting nozzle, an upstream side of the ejecting head in the circulation direction of the liquid, and stores the liquid. A first liquid reservoir configured to be able to release air bubbles mixed in the liquid to the atmosphere; and the liquid is sealed between the first liquid reservoir and the ejection head in the liquid circulation direction. And the second liquid storage part, and located between the first liquid storage part and the second liquid storage part in the liquid circulation direction, from the second liquid storage part to the first liquid storage part A liquid storage tank having a backflow prevention means for preventing the liquid from flowing back into the liquid, a liquid passage for supplying the liquid from the second liquid storage section to the ejection head, and a circulation direction of the liquid, Previous A liquid recirculation unit that is located between the first liquid reservoir and the liquid ejecting head and sucks the liquid in the ejecting head to recirculate the liquid to the first liquid reservoir; and the second liquid reservoir Liquid pressurizing means for pressurizing the liquid in the section to pressurize the liquid to the ejection head.
In the liquid ejecting apparatus according to an embodiment of the invention, the liquid pumping unit is connected to the plate via a plate disposed horizontally in the second liquid storage unit and a connecting member. A drive mechanism capable of moving the plate up and down, generating a negative pressure in the second liquid reservoir by pulling the plate upward, and pulling the plate downward in the second liquid reservoir The liquid can be pressurized.
In the liquid ejecting apparatus according to the embodiment of the invention, an opening is provided above the first liquid reservoir, and the pump connected to the opening through a passage, and the first liquid A separation plate that is provided in the reservoir and is located below the opening and allows gas to pass therethrough, and by driving the pump, bubbles on the lower surface side of the separation plate are moved to the upper surface side of the separation plate. It is possible to remove bubbles from the first liquid reservoir.

In such a liquid ejecting apparatus of the present invention, the liquid in the apparatus is circulated from the ejecting head to the first liquid storage portion and the liquid in the apparatus is circulated, thereby supplying the liquid in the ejecting head or the ejecting head The generated bubbles are separated into the first liquid reservoir. In the first liquid reservoir, the separated bubbles are released to the atmosphere, so that the bubbles in the liquid can be removed. In addition, when performing pressure cleaning, the second liquid reservoir is pressurized. At this time, since the backflow prevention means prevents the liquid from flowing back from the second liquid storage section to the first liquid storage section, the liquid is pumped with sufficient pressure to the downstream side of the second liquid storage section. It is possible to discharge the liquid in the ejection head.

For this reason, a mechanism for separating bubbles and a pressure mechanism for liquid for performing pressure cleaning can be integrally provided in the liquid storage tank while separation of bubbles in the liquid and pressure cleaning can be performed. it can. As a result, as compared with the case where these mechanisms are separately provided in the liquid ejecting apparatus, it is possible to suppress an increase in the size of the entire apparatus.

The first liquid storage section and the second liquid storage section have a passage cross section larger than that of the ejection head and the liquid passage, and the flow of the liquid is a slow place. It settles by gravity with the progress of. If the components in the precipitated liquid flow into the opening of the liquid passage from the second liquid storage portion due to the flow of the liquid generated when the liquid is jetted (or during pressure cleaning), the liquid passage is clogged and the like is caused. However, since the shielding member is erected on the upstream side of the opening from the bottom surface of the second liquid storage part, the precipitate in the second liquid storage part does not flow into the liquid passage.

In the liquid ejecting apparatus of the present invention described above, the tip of the shielding member may be bent in the direction opposite to the opening of the second liquid reservoir.

In this case, when the flow of the liquid flowing into the liquid passage from the second liquid reservoir is strong (for example,
Even when the sediment blocked at the position of the shielding member floats along the shielding member during pressure cleaning, the sediment does not get over the shielding member. Accordingly, it is possible to more reliably prevent the sediment from flowing into the liquid passage from the second liquid reservoir.

It is explanatory drawing which showed the rough structure of the liquid ejecting apparatus of a present Example using a line printer as an example. It is explanatory drawing which shows a state when a head unit is seen from the bottom face side. It is an explanatory view showing a mechanism for circulating ink in the ejection head. It is the perspective view which showed the detailed structure of the sub tank of a present Example. It is explanatory drawing which showed the method of removing the bubble isolate | separated by the subtank. It is explanatory drawing which showed the method of generating the pressurizing force for performing pressurization cleaning in a subtank. It is explanatory drawing which showed a mode that the deposit in a pressurization chamber was prevented from flowing into an ink supply channel | path by a defense wall. It is explanatory drawing which showed the shape of the defense wall of a modification. It is explanatory drawing which showed the reason for preventing a sediment from flowing out of a pressurization chamber effectively by using the defense wall of a modification.

Hereinafter, in order to clarify the contents of the present invention described above, examples will be described in the following order.
A. Device configuration:
B. Sub-tank structure of this example:
C. Variations:

A. Device configuration :
FIG. 1 is an explanatory diagram showing a rough structure of a liquid ejecting apparatus according to the present embodiment using a line printer 1 as an example. As shown in the figure, the line printer 1 of the present embodiment has a box-like outer shape, and a monitor panel 2 and an operation panel 3 for user operation are provided on the upper surface. It has been. Further, the front of the line printer 1 is provided with a cartridge replacement door 4 that is opened when the ink cartridge is replaced, and a paper feed door 5 that is opened when the printing paper is loaded. A paper discharge port 6 through which printed printing paper is discharged is provided.

Inside the line printer 1, a plurality of units or parts for executing various functions are mounted. First, a head unit 30 that ejects ink onto printing paper is provided at a substantially central position of the line printer 1. An ink supply unit 60 that supplies ink to the head unit 30 is provided below the head unit 30, and an ink cartridge 62 filled with ink is attached to the ink supply unit 60. In the line printer 1 of this embodiment, four colors of ink, black ink (K ink), cyan ink (C ink), magenta ink (M ink), and yellow ink (Y ink) can be used for printing. Corresponding to this, the ink supply unit 60 is filled with ink of each color 4.
Two ink cartridges 62 are mounted.

On the paper surface of FIG. 1, a paper feed cassette 10 into which printing paper is loaded is provided at the lower left position of the head unit 30, and the paper feed roller 20 is located at a position in contact with the upper surface of the right end of the paper feed cassette 10. Is provided. Further, a paper feed motor 22 is connected to the back side of the paper feed roller 20, and when the paper feed motor 22 is driven to rotate the paper feed roller 20, printing sheets are fed one by one from the paper feed cassette 10. It is conveyed toward the head unit 30. In FIG. 1, the conveyance path of the printing paper is indicated by a thick broken line.

In addition, an area on the right side of the head unit 30 is an empty space on the paper surface of FIG. 1, and a cap 40, a suction pump 50, a waste liquid tank 52, and the like are provided below the empty space. As will be described in detail later, in the line printer 1 of this embodiment, when the properties of the ink in the head unit 30 deteriorate due to the passage of time or the like, the head unit 30 is moved to an empty space on the right side. Later, by pressurizing the ink in the head unit 30, it is possible to perform a maintenance operation (pressure cleaning) for discharging the ink having deteriorated properties to the cap 40. Further, the ink discharged to the cap 40 by the pressure cleaning is sucked by the suction pump 50 and stored in the waste liquid tank 52.

A power supply unit 70 for supplying power to the line printer 1 and a control unit for controlling various movements of the line printer 1 are located immediately below the portion where the monitor panel 2 and the operation panel 3 are provided. 80 etc. are mounted.

Next, the printing operation of the line printer 1 will be described with reference to FIG. First, a plurality of printing sheets are loaded in the sheet feeding cassette 10. The printing paper loaded in the paper feed cassette 10 is pushed up by a spring (not shown), and the paper feed roller 2 provided above.
It is pressed to 0. The paper feed roller 20 is an elongated member having a substantially semicircular cross section formed by dividing a metal elongated cylinder in half in the length direction, and the side surface corresponding to the circumferential portion is formed of a rubber material. A paper feed motor 22 is connected to one end of the paper feed roller 20, and by rotating the paper feed roller 20 by the paper feed motor 22, printing sheets are fed one by one from the paper feed cassette 10 to the head unit 30. Send it out.

A plurality of guide rollers 24 are provided between the paper feed roller 20 and the head unit 30. The guide roller 24 is driven and rotated by a motor (not shown) to convey the printing paper to the head unit 30 while guiding the printing paper.

The head unit 30 is provided so as to straddle the printing paper on the printing paper conveyance path, and a plurality of inks are ejected to the bottom side of the head unit 30 (that is, the side facing the printing paper). Is provided (see FIG. 2). Head unit 3
0, the ink cartridge 62 of the ink supply unit 60 is connected via a passage (not shown), and the ink stored in the ink cartridge 62 is supplied from a plurality of ejection heads provided on the lower surface side of the head unit 30. Be injected.

FIG. 2 is an explanatory diagram showing a state when the head unit 30 is viewed from the bottom surface side (side facing the printing paper). As shown in the figure, on the bottom surface of the head unit 30 of the present embodiment, there are provided four sets (a total of 24) of jet heads 32 each having a substantially rectangular shape. In addition, three jet heads 32 in each group are arranged in two rows by three, and the jet heads 32 in each row are arranged alternately. Further, each ejection head 32 is provided with a plurality of ejection nozzles that eject ink.

Such jet heads 32 are arranged in a staggered manner, so that six jet heads 3 are arranged.
2 integrally form one injection unit 33. As described above, since the head unit 30 of the present embodiment is provided with 24 ejection heads 32, eventually, there are four ejection units 33, and each ejection unit 33 uses Y ink. An ejection unit 33y that ejects M, an ejection unit 33m that ejects M ink, an ejection unit 33c that ejects C ink, and an ejection unit 33k that ejects K ink.

Below the head unit 30, facing the bottom surface of the head unit 30,
A platen that supports the printing paper from the back is provided (not shown). Feed roller 2
0 and the printing paper conveyed by the guide roller 24 are conveyed on the platen,
During this time, ink is ejected from a plurality of ejecting heads 32 provided on the bottom surface of the head unit 30, and an image is printed on the printing paper. The printing paper on which the image is thus printed is bent downward in the traveling direction by the guide roller 24 provided on the downstream side of the head unit 30, and then passes through the lower side of the waste liquid tank 52 from the paper discharge port 6 to the line printer. 1 is discharged to the outside.

Also, air that has been dissolved in the ink may be dissolved out, or air bubbles may be generated in the ink when external air is involved. When the generated bubbles flow into any one of the plurality of ejection heads 32, the ejection head 32 cannot appropriately eject ink. Therefore, the air bubbles mixed in the ink are separated by circulating the ink in the ejection head 32 using the following mechanism.

FIG. 3 is an explanatory diagram showing an ink circulation mechanism provided in the line printer 1 of the present embodiment. As described above with reference to FIGS. 1 and 2, the line printer 1 according to the present embodiment includes four inks of C (cyan) ink, M (magenta) ink, Y (yellow) ink, and K (black) ink. Various types of ink are mounted, and these inks are supplied to the ejection head 32 of the ejection unit 33 provided for each type of ink. The ink circulation mechanism circulates ink for each ejection unit 33. However, since the configuration of each circulation mechanism is completely the same, only one injection unit 33 is shown as a representative in FIG.

As described above with reference to FIG. 2, the ejection unit 33 includes six ejection heads 32, and correspondingly, six ejection heads 32 are displayed in FIG. 3. These 6
Ink is supplied to the two ejection heads 32 from the ink cartridge 62 through the following path. First, the ink cartridge 62 is connected to the circulation pump 102 via the ink passage 110 and the switching valve 100, and the ink passage 112 is connected to the circulation pump 102.
The sub-tank 114 is connected to the ejection head 32 via the ink supply passage 116 from the sub-tank 114. In addition, on the downstream side of the sub tank 114, the ink supply passage 116 is branched and connected to each of the six ejection heads 32. In FIG. 3, the ink supply passage 116 from the sub tank 114 to the ejection head 32 is indicated by a thick solid line. Therefore, by operating the circulation pump 102, the ink in the ink cartridge 62 can be sucked out and supplied to the sub tank 114, and the ink can be supplied to the ejection head 32 via the sub tank 114.

The path for circulating the ink in the ejection head 32 is configured as follows.
That is, each of the six ejection heads 32 is provided with an ink circulation path 118.
The ink circulation passages 118 from the ejection heads 32 merge and are connected to the switching valve 100.
In FIG. 3, the ink circulation path 118 from the ejection head 32 to the switching valve 100 is indicated by a thick broken line.

In the line printer 1 of the present embodiment having the ink circulation mechanism as described above, the air bubbles mixed in the ink are separated by circulating the ink as follows. First, the switching valve 10
By switching the connection state of 0, the ink circulation path 118 from the ejection head 32 and the ink path 112 following the circulation pump 102 are communicated, and the circulation pump 102 is driven in this state. Then, the ink in the ejection head 32 is circulated through the ink circulation passage 118 and the circulation pump 102.
And is supplied to the sub tank 114 via the ink passage 112. When ink is sucked out from the ejection head 32 in this way, the pressure in the ejection head 32 is reduced.
Ink is supplied from the sub tank 114 to the ejection head 32 via the ink supply passage 116. As a result, the ink circulates between the sub tank 114 and the ejection head 32. The sub-tank 114 has a passage cross section larger than the ejection head 32 and the ink passage (ink supply passage 116, ink circulation passage 118, ink passage 112), etc., and is a place where the flow of ink is gentle. Accordingly, in the sub tank 114, the bubbles that have flowed with the ink float upward, and the ink and the bubbles are separated.

Here, in addition to the mechanism for separating the air bubbles mixed in the ink as described above, the sub-tank 114 of this embodiment is provided with a mechanism for generating the pressure for performing the pressure cleaning described above. Yes. That is, as will be described in detail later, in the line printer 1 of the present embodiment, the ink stored in the sub-tank 114 is pumped to pressurize the interior of the ejection head 32, whereby the ink whose properties have deteriorated from the ejection head 32. It is possible to discharge. Therefore, in the following, the structure of the sub tank 114 of this embodiment provided with these mechanisms will be described.

B. Sub-tank structure of this example:
FIG. 4 is a perspective view showing a detailed structure of the sub tank 114 of this embodiment. The outer shape of the sub tank 114 of this embodiment is a substantially rectangular parallelepiped shape with a narrow width. The sub tank 114 is supplied to the separation head 120 for separating bubbles mixed in the ink and the ejection head 32. A pressurizing chamber 130 for pressurizing ink is provided. A partition 140 is provided between the separation chamber 120 and the pressurization chamber 130.

The liquid supplied into the sub tank 114 through the ink passage 112 first flows into the separation chamber 120. The separation chamber 120 is shaped so that the chamber is narrowed toward the upper side of the sub tank 114, and the separation chamber 120 is opened when it reaches the upper surface of the sub tank 114. A separation plate 122 is provided at a position slightly below the portion where the separation chamber 120 is opened, and is connected to a vacuum pump 124 via a passage at the point where the separation chamber 120 is opened. As will be described in detail later, by providing the separation plate 122 and the vacuum pump 124 in the separation chamber 120, it is possible to remove the bubbles carried by the circulation of the ink from the separation chamber 120.

The ink supplied to the separation chamber 120 flows into the pressure chamber 130 through the internal passage 142 provided in the partition wall 140. A check valve 144 is provided in the internal passage 142 to prevent the ink flowing into the pressurizing chamber 130 from flowing back to the separation chamber 120. Further, a filter 146 is provided at a portion where the internal passage 142 is connected to the pressurizing chamber 130, and foreign matters such as dust mixed in the ink are removed by the filter 146.

A substantially horizontal pressure plate 131 is provided inside the pressure chamber 130. The pressure plate 131 is
It is connected to the drive mechanism 133 via the connecting rod 132, and by moving the connecting rod 132 up and down using the drive mechanism 133, the pressurizing plate 131 is pushed below the pressurizing chamber 130,
Or it can be pulled upward. The pressure plate 131 is normally in a state of being provided at a predetermined height, so that the ink flowing into the pressure chamber 130 is
After passing through the pressure chamber 130 and flowing into the ink supply passage 116, the ink is supplied to the ejection head 32. In addition, a defense wall 135 having a width substantially the same as the depth of the pressurizing chamber 130 is erected at a position slightly upstream of the inflow port 134 where the ink supply passage 116 opens into the pressurizing chamber 130.
The reason for providing such a defense wall 135 will be described in detail later.

In the sub tank 114 of the present embodiment configured as described above, air bubbles mixed in the ink carried from the ejection head 32 by the circulation of the ink can be removed, and also necessary for pressure cleaning in the sub tank 114. It is possible to generate a large pressure. Although the method will be described below, first, a method for removing bubbles from the inside of the ejection head 32 will be described.

FIG. 5 is an explanatory view showing a method of removing bubbles in the ink by the sub tank 114. As described above, when the circulation pump 102 is driven in a state where the ink circulation path 118 from the ejection head 32 and the ink path 112 to the sub tank 114 are in communication, the sub tank 114 is driven.
And the ejecting head 32 circulate ink (see FIG. 3). At this time, in the separation chamber 120 where the flow of ink is gentle, as shown in FIG. 5A, the bubbles that have flowed along with the ink float above the separation chamber 120 and are provided above the separation chamber 120. Separation plate 122
To reach the height of.

Here, the separation plate 122 of the present embodiment is manufactured using a material capable of slightly passing gas. Therefore, by driving the vacuum pump 124 connected to the opening of the separation chamber 120 and applying a negative pressure to the upper surface side of the separation plate 122, as shown in FIG.
Bubbles on the lower surface side of the separation plate 122 can be sucked out and transmitted to the upper surface side of the separation plate 122. As a result, the bubbles separated into the separation chamber 120 by the circulation of ink can be removed from the separation chamber 120. Further, in the sub-tank 114 of the present embodiment, a pressurizing force necessary for pressure cleaning is generated as follows.

FIG. 6 is an explanatory view showing a method of generating a pressurizing force for performing pressure cleaning in the sub tank 114. As described above, in the pressurizing chamber 130 provided in the sub-tank 114 of this embodiment, the pressurizing plate 131 is usually provided at a predetermined height. As shown in FIG. 6A, the pressure plate 131 is pulled up using the drive mechanism 133. Then, the internal volume of the pressurizing chamber 130 is increased, and accordingly, a negative pressure is generated in the pressurizing chamber 130. As a result, ink is supplied from the separation chamber 120 to the pressure chamber 130 via the internal passage 142. Since the pressurizing chamber 130 is also connected to the ink supply passage 116, the negative pressure in the pressurizing chamber 130 is rapidly increased, thereby suppressing the back flow of ink from the downstream side to the pressurizing chamber 130. Therefore, the pressure plate 131 is slowly pulled up.

After the ink is taken into the pressure chamber 130 in this way, the ink in the pressure chamber 130 is pressurized by pushing the pressure plate 131 toward the bottom surface of the pressure chamber 130 using the drive mechanism 133. At this time, the ink pressurized by the pressure plate 131 tends to flow out to both of the two passages (the internal passage 142 and the ink supply passage 116) connected to the pressurization chamber 130. Since the check valve 144 is provided in the passage 142, the internal passage 1
Ink does not flow back through 42. Accordingly, the pressurized ink flows only into the ink supply passage 116, and as a result, the ink is pumped to the ejection head 32. In this way, by using the pressure plate 131 to pump the ink in the pressure chamber 130, it is possible to discharge the ink having deteriorated properties from the ejection head 32 (pressure cleaning).

As described above, in the sub tank 114 according to the present embodiment, it is possible to remove bubbles in the sub tank 114 and generate a pressurizing force necessary for pressure cleaning. Here, as another method for generating the pressure during pressure cleaning, for example, a dedicated pressure mechanism may be provided and ink may be pumped to the ejection head 32 using this pressure mechanism. In this case, the line printer 1 is increased in size by providing the pressurizing mechanism. Compared with such a method, if the pressurizing force is generated in the sub-tank 114 as in the present embodiment, it is not necessary to provide a separate pressurizing mechanism, and thus the line printer 1 is prevented from being enlarged. It becomes possible.

Further, as described above, the sub tank 114 has a passage cross section larger than that of the ejection head 32 and the ink passage, and is a place where the ink flow is gentle.
Within 4, the components contained in the ink may precipitate due to gravity over time. When the components in the precipitated ink flow into the ink supply passage 116 from the pressure chamber 130,
Although adverse effects such as clogging of sediments may occur, since the above-described defense wall 135 is provided in the sub tank 114 of this embodiment, such adverse effects are prevented from occurring. This point will be described below.

FIG. 7 is an explanatory view showing a state in which the deposit in the pressurizing chamber 130 is prevented from flowing into the ink supply passage 116 by the defense wall 135. When the ink in the pressurizing chamber 130 flows into the ink supply passage 116 by ejecting ink from the ejecting head 32 (or by pressurizing the ink in the pressurizing chamber 130 and performing pressure cleaning), As shown in FIG. 7, the components in the ink that have settled on the bottom surface of the pressurizing chamber 130 gradually flow toward the inlet 134. However, as described above, the defense wall 135 having the same width as the depth of the pressurizing chamber 130 is provided slightly upstream of the inflow port 134. Therefore, since the sediment is blocked at the position of the defense wall 135, it is possible to prevent adverse effects such as clogging the sediment in the passage.

Further, as described above, since the defense wall 135 is erected from the bottom surface of the pressurizing chamber 130,
The pressure plate 131 also serves as a stopper that supports the pressure plate 131 from below so that the pressure plate 131 is not pushed down too much when the ink is pressurized. Accordingly, since the pressure plate 131 is not pushed below the upper end of the protective wall 135, the pressure plate 131 pushes out the components in the ink deposited on the bottom surface of the pressure chamber 130. It is possible to avoid a situation in which the sediment flows out to the downstream side.

C. Modified example:
In the line printer 1 of the above-described embodiment, the protective wall 135 having a sufficient height is provided on the upstream side of the inflow port 134 so that the precipitate in the pressurizing chamber 130 does not flow downstream when the ink is pressurized. Explained. Here, in order to enhance the effect of preventing the sediment in the pressurizing chamber 130 from flowing downstream, the protective wall 135 may have the following shape.

FIG. 8 is an explanatory view showing the shape of the defense wall 135 provided in the pressurizing chamber 130 of the modified example. The defense wall 135 shown in FIG. 8 is formed such that the tip portion of the defense wall 135 is bent in the opposite direction with respect to the inflow port 134, and the bent portion is substantially parallel to the bottom surface of the pressurizing chamber 130. Has been. Using this shape of the defense wall 135, as shown below,
It is possible to effectively prevent the precipitate in the pressurizing chamber 130 from flowing downstream.

FIG. 9 is an explanatory diagram showing the reason why the deposit in the pressurizing chamber 130 is effectively prevented from flowing out by using the modified defense wall 135. As described above, an ink flow is generated in the pressurizing chamber 130 toward the inlet 134, and in such a flow, the defense wall 135 is included.
The flow to get over is also included. Therefore, the components in the ink that have settled in the pressurizing chamber 130 may be rolled up and get over the protective wall 135. Therefore, as described above, when the front end of the defense wall 135 is bent to the opposite side of the inflow port 134 and the bent portion is substantially parallel to the bottom surface of the pressurizing chamber 130, as shown in FIG. Even if the sediment is rolled up, it is blocked by the upper end portion of the protective wall 135. For this reason, since the sediment cannot get over the protective wall 135, it is possible to effectively prevent the sediment in the pressurizing chamber 130 from flowing downstream.

As described above, the defense wall 135 also serves as a stopper that supports the pressure plate 131 from below so that the pressure plate 131 is not pushed too much when the ink is pressurized. From this point, when the defense wall 135 shown in FIG. 9 is viewed, the upper end of the defense wall 135 is bent and formed substantially parallel to the bottom surface, so that the contact portion between the pressure plate 131 and the defense wall 135 is reduced. A large area can be taken. Accordingly, since the pressure applied to the pressure plate 131 at the time of contact with the defense wall 135 can be dispersed, it is possible to reduce damage to the pressure plate 131.

As mentioned above, although the Example of this invention was described, this invention is not limited above,
The present invention can be implemented in various modes without departing from the gist thereof.

1 ... Line printer, 30 ... Head unit, 32 ... Ejecting head,
40 ... Cap, 50 ... Suction pump, 60 ... Ink supply unit,
62 ... Ink cartridge, 100 ... Switching valve, 102 ... Circulation pump,
110: Ink passage, 112 ... Ink passage, 114 ... Sub tank,
116: Ink supply passage, 118 ... Ink circulation passage, 120 ... Separation chamber,
122 ... Separator plate, 124 ... Vacuum pump, 130 ... Pressurizing chamber,
131 ... Pressure plate, 132 ... Connecting rod, 133 ... Drive mechanism,
134 ... Inlet, 135 ... Defense wall, 140 ... Bulkhead,
142: internal passage 144: check valve 146: filter

Claims (8)

A liquid ejecting apparatus that ejects liquid from an ejection nozzle provided in an ejection head,
A first liquid storage section provided upstream of the ejection head in the liquid circulation direction and configured to store the liquid, and configured to discharge air bubbles mixed in the liquid to the atmosphere; and A second liquid storage part that is positioned between the first liquid storage part and the ejection head in the circulation direction and stores the liquid in a sealed state, and the second liquid storage part to the first liquid storage part. And a backflow prevention means for preventing the liquid from flowing back, a liquid storage tank provided inside,
A liquid passage for supplying the liquid from the second liquid reservoir to the ejection head;
Liquid recirculation means for recirculating the liquid to the first liquid reservoir by sucking out the liquid in the ejection head;
Liquid pumping means for pumping the liquid to the ejection head by pressurizing the liquid in the second liquid storage section;
The second liquid reservoir is open to the bottom surface of the second liquid reservoir and communicates with the liquid passage at a position upstream of the first opening in the liquid circulation direction. A liquid ejecting apparatus comprising: a shielding member that is erected from the bottom surface and capable of preventing the sediment that has settled in the second liquid storage portion from flowing into the opening. The liquid ejecting apparatus according to claim 1,
The liquid recirculation unit is a liquid ejecting apparatus positioned between the first liquid storage unit and the liquid ejecting head in the liquid circulation direction.   3. The liquid ejecting apparatus according to claim 1, wherein the liquid pumping unit is connected to the plate via a plate disposed horizontally in the second liquid reservoir and a connecting member, A drive mechanism capable of moving the plate up and down, generating a negative pressure in the second liquid reservoir by pulling the plate upward, and pulling the plate downward to lower the second liquid reservoir. A liquid ejecting apparatus capable of pressurizing the liquid in the unit. The liquid ejecting apparatus according to any one of claims 1 to 3,
A second opening is provided above the first liquid reservoir, a pump connected to the second opening via a passage, and the second opening provided in the first liquid reservoir. A separation plate that is positioned below and capable of passing gas, and by driving the pump, bubbles on the lower surface side of the separation plate are transmitted to the upper surface side of the separation plate, and the first liquid A liquid ejecting apparatus capable of removing bubbles from a reservoir. The liquid ejecting apparatus according to any one of claims 1 to 4,
The liquid ejecting apparatus, wherein the shielding member is a member having a distal end bent in an opposite direction with respect to the first opening. An ejection head that ejects liquid from the ejection nozzle;
A first liquid storage section provided upstream of the ejection head in the liquid circulation direction and configured to store the liquid, and configured to discharge air bubbles mixed in the liquid to the atmosphere; and A second liquid storage section that is positioned between the first liquid storage section and the ejection head in the circulation direction and stores the liquid in a sealed state; and the first liquid storage section and the A liquid storage tank that is located between the second liquid storage unit and has a backflow prevention unit that prevents the liquid from flowing back from the second liquid storage unit to the first liquid storage unit ;
A liquid passage for supplying the liquid from the second liquid reservoir to the ejection head;
Liquid recirculation, which is located between the first liquid reservoir and the liquid ejecting head in the circulation direction of the liquid and recirculates the liquid to the first liquid reservoir by sucking out the liquid in the ejecting head. Means,
A liquid ejecting apparatus comprising: a liquid pumping unit that pressurizes the liquid in the second liquid storage unit to pump the liquid to the ejecting head.   The liquid ejecting apparatus according to claim 6, wherein the liquid pumping unit is connected to the plate via a plate disposed horizontally in the second liquid storage unit and a connecting member, A drive mechanism capable of moving up and down, generating a negative pressure in the second liquid reservoir by pulling up the plate upward, and pulling down the plate downward in the second liquid reservoir A liquid ejecting apparatus capable of pressurizing the liquid. The liquid ejecting apparatus according to claim 6 or 7,
An opening is provided above the first liquid reservoir, a pump connected to the opening via a passage, and a gas located in the first liquid reservoir and located below the opening. A separation plate that can pass through, and by driving the pump, bubbles on the lower surface side of the separation plate are transmitted to the upper surface side of the separation plate, and the bubbles are removed from the first liquid reservoir. Liquid ejecting apparatus that is capable of doing.

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