KR101680436B1 - Inkjet recording apparatus - Google Patents

Abstract

A plurality of heads 3 for ejecting ink of the same color on a recording medium, an ink tank 84 for storing ink to be supplied to each of the plurality of heads, and a liquid delivering section 850 for sending ink from the ink tank to the head side And each head has a manifold in which ink is filled, and first and second ports (341, 342) communicating with the manifold (34), and the first port and the second port And a control section 9 for individually opening and closing the valves connected to the first and second ports of the respective heads, respectively, by providing valves 874 and 875 which can be opened and closed in the ink flow path following each of the ports. The ink ejection is enabled for each head, thereby enabling quick maintenance while suppressing ink consumption.

Description

[0001] INKJET RECORDING APPARATUS [0002]

The present invention relates to an ink jet recording apparatus provided with an ink supply device for supplying ink to a head.

There is an ink jet printer as a recording apparatus capable of forming an image on various recording media such as ordinary or plastic thin plates. The inkjet printer has a head for ejecting ink from a nozzle hole. An image is formed on the recording medium by ejecting ink as fine droplets from the nozzle hole of the head toward the recording medium.

The head is connected to a tank in which ink is stored, and ink is supplied to the head from the tank.

At this time, if dissolved gas or air bubbles are mixed in the ink, or foreign matter such as dust is mixed in the ink, it causes the discharge failure. Therefore, in the conventional ink jet recording apparatus, maintenance of the head is performed in the home position.

Maintenance of the head is performed by closing the electromagnetic valve provided in the ink flow path for supplying the ink from the ink tank to the head by closely contacting the cap case of the capping means provided at the home position with the nozzle of the head, And the electromagnetic valve is opened after lowering to the target pressure. As a result, the ink in the ink tank rapidly flows into the cap case through the head, and the bubbles in the head and the dirt and foreign matter adhering to the inside of the head can be discharged to the outside of the head owing to the momentum For example, see Patent Document 1).

Another ink-jet recording apparatus has a supply flow path for supplying ink to the head and a recovery flow path for recovering surplus ink from the head, and supplies ink to the head from the supply flow path during maintenance, And the ink is discharged from the recovery flow path to the head (see, for example, Patent Document 2).

Further, the head is provided with a filter for filtering dust and foreign matter in front of the recovery flow path. That is, by circulating the ink with respect to the head, it is possible to remove the ink mixture or the like with a filter.

In another inkjet recording apparatus, a plurality of heads are provided, and each head is provided with a supply port for supplying ink therein and a discharge port for discharging the supplied ink. By connecting the discharge port of each head to the supply port of the other head, it is possible to perform maintenance on all the heads by connecting the entire heads in series and supplying ink from one end (see, for example, Patent 3).

Japanese Patent Application Laid-Open No. 2001-113726 Japanese Patent Application Laid-Open No. 2007-261234 Japanese Patent Application Laid-Open No. 2009-285900

However, in the conventional ink-jet recording apparatus described in Patent Document 1, a plurality of heads are simultaneously capped, and ink is ejected from the entire head to the cap case. As a result, there has been a problem in that capping is performed for a head having good ejection at the same time, and consumption of unnecessary ink is increased.

In this regard, in the inkjet recording apparatus of Patent Document 2, the ink that has passed through the head is recovered in the recovery channel and returned to the ink tank, so that unnecessary consumption of ink is not caused. However, since the ink is returned to the ink tank, it has become necessary to provide a filter in each head so as to prevent the ingress of water into the ink tank. Further, by providing a filter on each head, it is necessary to periodically check the filter.

In the inkjet recording apparatus of Patent Document 3, since the heads are connected in series, one filter is sufficient, but there is a problem that a long time is required for the maintenance work due to ink circulation due to the series connection.

An object of the present invention is to provide an ink-jet recording apparatus that can rapidly maintain the maintenance of the head while suppressing the consumption of ink.

According to an aspect of the present invention, there is provided an ink jet recording head comprising: a plurality of heads for ejecting ink of the same color on a recording medium; an ink tank for storing ink to be supplied to each of the plurality of heads; Wherein each of the heads has a manifold in which ink is filled and first and second ports communicating with the manifold, wherein each of the first port and the second port of the head And a control section for separately controlling the opening and closing of the valve following each of the first and second ports of each of the heads.

Further, the present invention may have a configuration in which the first ports of all of the heads have a common flow passage connected in parallel through the valve, and ink is supplied to each of the heads through the common flow passage.

Further, the present invention is characterized by a discharge flow path connected to the common flow path for discharging the ink inside the common flow path, and a valve that can be switched on and off provided in the discharge flow path, and the control section controls .

Further, the present invention is characterized in that, in the middle of the ink flow path from the ink tank to each of the heads, a negative pressure forming portion for maintaining the inside of each of the heads at a negative pressure lower than the atmospheric pressure is provided, And a valve that can be opened and closed for blocking the pressure at the time of ink supply may be provided before and after the negative pressure forming portion.

In order to solve the problems described above, the present invention has a configuration in which a valve is provided for each of the first and second ports of a plurality of heads, and the opening and closing of each valve is individually controlled by the control unit. It is possible to selectively supply the ink only to the head which is the object of the maintenance in the case of necessity of maintenance, and it is possible to reduce the consumption amount of the ink in the maintenance work.

Further, even if the ink used for the maintenance is not returned to the ink tank, it is possible to reduce the consumption of ink in the maintenance work, so that it is not necessary to provide a filter for each head. As a result, it is possible to avoid the occurrence of clogging of the nozzle in the head due to the foreign matter filtered by the filter, and it may not be necessary to check the filter.

In addition, as compared with the case where maintenance is performed by connecting all the heads in series, the maintenance can be performed only on a part of the maintenance target head, so that the time required can be greatly shortened.

In the case of a configuration in which the common flow path connected in parallel via the valve to the first port of all the heads is provided, unlike the case where a plurality of heads are connected in series, So that maintenance can be effectively performed in a short period of time.

In addition, for example, pressure adjustment in the head can be performed on the entire head at one time by performing this through the common flow path.

In addition, when the discharge flow path for discharging the ink inside the common flow path is provided, the bubbles generated in the common flow path can be easily discharged from the discharge flow path.

Further, in the case of the configuration including the negative pressure forming portion and the bypass passage, even when a higher pressure than the normal pressure is applied to the head during maintenance, the influence of the pressure can be avoided by closing the front and rear valves of the negative pressure forming portion, The negative pressure forming portion can be protected.

1 is a perspective view of an inkjet recording apparatus.
2 is a plan view showing the arrangement of heads on the carriage.
3 is a cross-sectional view showing the internal structure of the head.
4 is a schematic diagram showing an outline of an ink supply device.
Fig. 5 is an explanatory diagram showing the connection state of each head and the common flow path.
6 is a block diagram showing a control system of the inkjet recording apparatus.
7 is a flow chart showing the liquid level monitoring control.
8 is a flowchart showing the head maintenance control for a part of the heads to be subjected to maintenance.
Fig. 9 is a flowchart showing the liquid delivery control.
10 is a flowchart showing the negative pressure forming sub-pressure regulating control.
11 is a flowchart showing the wiping control.
FIG. 12A is a chart showing a recovery situation of nozzle clogging in the case where the recording operation valve of a predetermined head is opened and the supply pressure in the maintenance in the state where the maintenance valve is closed is changed stepwise.
FIG. 12B is a chart showing a bubble removal state in the head when the supply pressure in the maintenance operation is changed stepwise in a state where both the recording operation valve and the maintenance valve of the predetermined head are opened.
13 is a flowchart showing head maintenance control for the entire head.
14A is a schematic front view showing a modified example of the common flow path, and shows an example in which the eighth ink flow path is connected to the right end portion of the common flow path.
Fig. 14B is a schematic front view showing a modified example of the common flow path, showing an example in which the eighth ink flow path is connected to the left end of the common flow path. Fig.
Fig. 14C is a schematic front view showing a modification of the common flow passage, showing an example in which the eighth ink flow passage is connected to the central portion of the common flow passage. Fig.

The ink-jet recording apparatus 10 equipped with the ink supply apparatus according to the embodiment of the present invention will be described with reference to Figs. 1 to 13. Fig. 1 is a perspective view showing the whole of the inkjet recording apparatus 10.

The inkjet recording apparatus 10 includes a carriage 20 for carrying a recording medium along a horizontal direction and a carriage (not shown) for mounting a plurality of heads 3 (see Fig. 2) A main maintenance unit 5 for carrying the carriage 4 along the horizontal direction perpendicular to the conveyance direction of the recording medium and a maintenance unit 5 for maintenance of each head 3 mounted on the carriage 4, A nozzle moisturizing section 6 for moisturizing the nozzles 311 of each head 3 mounted on the carriage 4 and an ink supply section 6 for supplying ink to each head 3 mounted on the carriage 4 The ink supply device 8 (see Fig. 4), a control device 9 (see Fig. 6) as a control unit for controlling these components, and a frame 100 for supporting the whole.

In the following description, it is assumed that the direction along the transport direction of the recording medium is the Y axis direction, the direction along the transport direction of the carriage 4 is the X axis direction or the main scanning direction, and the vertical direction is the Z axis Direction.

[Return Device]

The conveying apparatus 20 includes a driving roller 21 and a driven roller (not shown), a driving motor 22, and a conveying belt 23.

The drive roller 21 and the driven roller are rotatably supported by a shaft, and the drive roller 21 is arranged to extend in the main-scan direction X. The drive motor 22 is a drive source for rotationally driving the drive roller 21 and is provided at one end of the drive roller 21. [

The conveyor belt 23 is formed in an endless shape and runs between the drive roller 21 and the driven roller. When the drive roller 21 rotates, the conveyor belt 23 circulates between the drive roller 21 and the driven roller, conveys the recording medium stacked on the upper surface thereof in the conveying direction F along the Y-axis direction, When the rotation of the rollers 21 is stopped, the main circulation between the rollers is stopped and the conveyance of the recording medium is stopped.

The drive motor 22 rotates the drive roller 21 by a predetermined amount and drives the recording medium to be transported by the drive motor 21 when the head 3 finishes scanning the one- When the head 3 starts to scan in the direction opposite to the main scanning direction X and finishes, the driving roller 21 is rotated again by a predetermined amount to move the recording medium in the transport direction F for a predetermined distance to stop the recording medium, so that the recording medium is intermittently conveyed.

As the recording medium, a resin film, a metal or the like can be used in addition to a paper or fabric (fabric).

[frame]

1, the frame 100 includes a rectangular main body portion 101 extending along the X-axis direction, a first toothed portion 102 (see Fig. 1) supporting the one end portion in the X- And a second toe portion 103 for supporting the other end portion in the X-axis direction of the main body portion 101. [

The first toe portion 102 supports one end of the main body portion 101 from below while storing and holding the nozzle moisturizing portion 6 therein. The second toe portion 103 supports the other end of the main body portion 101 from below while storing and retaining the maintenance portion 7 therein.

The main body 101 stores and holds a pair of carriage rails 51 and 51 of the main scanning device 5 described later in the X axis direction while the carriage 4 is in the main body 101 in the X-axis direction.

The first toe portion 102 and the second toe portion 103 are disposed on both sides in the X axis direction with the carrying device 20 interposed therebetween and the main body portion 101 is supported by the carrying device 20, As shown in Fig. Thereby, the ink is ejected from each head 3 mounted on the carriage 4 while conveying the carriage 4 in the direction perpendicular to the conveyance direction of the recording medium by the conveyance device 20, .

[Main equipment and carriage]

The main scanning apparatus 5 has a pair of rod-shaped carriage rails 51, 51 which are supported so as to extend along the X-axis direction in the main body 101 of the frame 100. As shown in Fig. These pair of carriage rails 51 and 51 are provided so as to extend over the conveying belt 23 of the conveying device 20. [ On the carriage rails 51, 51, a box-shaped carriage 4 is supported so as to be reciprocally movable along the X-axis direction.

The carriage 4 is a substantially rectangular housing with an open top, and a plurality of heads 3 are mounted on the bottom plate. 1, the carriage 4 has arm portions 42 and 42 extending toward both sides in the Y-axis direction on both sides in the Y-axis direction, and each of the arm portions 42, 42 are respectively mounted on the carriage rails 51, 51 via the linear guides so that they can slide on the carriage rails 51, 51 along the X-axis direction.

A linear motor is provided between the carriage rails 51 and 51 and the arm portions 42 and 42 of the carriage 4. That is, each of the carriage rails 51 and 51 is equipped with a stator of a linear motor, and each of the arm portions 42 and 42 of the carriage 4 is equipped with a mover. By controlling the current of the coil on the stator side, 4 are given a carrying operation along the X-axis direction.

2 is a schematic explanatory view of the bottom plate 41 of the carriage 4 as viewed from above. In this inkjet recording apparatus 10, Y (yellow), Lm (light magenta), Or (orange), M (magenta), Bk (black) , And Lc (light cyan), and a total of 81 heads 3 are provided on the bottom plate of the carriage 4, respectively.

The head group of each color is arranged in the order of Y, Lm, Or, M, Bk, Bl, Lk, C and Lc along the X- Are arranged in a zigzag shape along the Y-axis direction.

The bottom plate 41 is provided with slit-shaped openings along the Y-axis direction for each mounting position of each head 3 and each head 3 provided from above to the bottom plate 41 is fixed to the carriage 4) in the ink droplet.

As described above, by arranging the nine heads 3 in a staggered shape for each color, it is possible to arrange the nozzles 3 of the carriage 4 on the bottom plate 41 in an arbitrary So that ink can be ejected in each color.

[head]

3 is a cross-sectional view showing a schematic structure of the head 3. As shown in Fig. The head 3 has a nozzle plate 31 in which a plurality of nozzles 311 for ejecting ink are formed and a plurality of channels 321 and channels 321 for guiding ink to the nozzles 311, A wiring board 33 for applying a driving voltage to each piezoelectric element 322 of the head chip 32 and a head chip 32 for applying a driving voltage to the piezoelectric element 322 of the head chip 32. The head chip 32 has a plurality of piezoelectric elements 322, And a manifold 34 for introducing ink to each channel 321 of the ink tank 32 through a filter 343.

The nozzle plate 31 is a rectangular flat plate and the flat surface thereof is parallel to the XY plane and the longitudinal direction thereof is parallel to the Y axis direction in a state in which the head 3 is mounted on the carriage 4.

In the nozzle plate 31, a plurality of through holes, which become the nozzles 311, are arranged in a line along the Y-axis direction.

The head chip 32 is formed in a rectangular parallelepiped shape, and a nozzle plate 31 is provided on the bottom surface thereof. A plurality of channels 321 are arranged in a line along the Y-axis direction in accordance with the arrangement of the nozzles 311 of the nozzle plate 31. As shown in FIG. Each of the channels 321 is an ink flow path passing through the head chip 32. The ink in the manifold 34 can be individually guided to the nozzle 311. [ A piezoelectric element 322 is provided adjacent to each of the channels 321. By selectively applying a voltage to any piezoelectric element 322, the piezoelectric element 322 expands or contracts, So that the ink can be discharged from the corresponding nozzle 311.

On the top surface of the head chip 32, a wiring board 33 is provided. The wiring board 33 is connected to a head drive circuit (not shown) via a flexible board, and wiring for applying a drive voltage from the head drive circuit to each piezoelectric element 322 of the head chip 32 .

The wiring substrate 33 is provided in the manifold 34 so as to close the opened lower portion of the manifold 34 so that the ink in the manifold 34 flows into the respective channels 321 of the head chip 32, And a rectangular opening is formed so as to be communicated to the side of the valve body.

The manifold 34 is an inner hollow rectangular parallelepiped arranged in the longitudinal direction along the Y axis direction. As described above, the bottom portion of the manifold 34 is open, but the wiring substrate 33 is inserted into the open portion, .

A cylindrical first port 341 and a second port 342 are formed so as to communicate with the inside of the one end side and the other end side of the manifold 34 in the Y axis direction.

The inside of the manifold 34 is divided into upper and lower portions by a filter 343 for filtering the mixture of ink and the upper region is connected to the first port 341 and the second port 342, Which is connected to the head chip 32. That is, the ink supplied from the outside into the manifold 34 by the first port 341 or the second port 342 is filtered by the filter 343 to move toward the head chip 32, 311).

[Maintenance Department]

The maintenance section 7 performs maintenance of each head 3 in the non-recording operation. The maintenance part 7 is provided at one end side of the carriage rails 51 and 51, away from the conveying device 20. [ That is, maintenance is performed in a state in which the carriage 4 is moved to a position opposed to the maintenance part 7 at one end of the carriage rails 51, 51.

The maintenance section 7 includes a cleaning device for wiping off contamination on the bottom surface of the nozzle plate 31 of each head 3 and a cleaning device for cleaning the surface of the base plate 3 when discharging ink by the head 3 to be maintenance- And an ink tray 71 (see Fig. 4).

The cleaning apparatus is mainly composed of a cleaning roller which is rotatable about a rotation axis along the X axis direction which is in sliding contact with the lower surface of the nozzle plate 31 and a roller transport mechanism which conveys the cleaning roller along the Y axis direction . The width of the cleaning roller in the X-axis direction is set so that the head group of three colors in the nine-color head group mounted on the carriage 4 can be wiped off. Perform cleaning. This prevents clogging of the nozzle 311 due to solidification of the ink.

The ejection of the ink to the ink tray 71 at the time of maintenance is carried out with the ink supply pressure of the ink supply device 8 instead of driving the piezoelectric element 322 of the head 3, Clogging of the ink flow path in the ink tank 3 can be solved.

[Nozzle moisturizing part]

The nozzle moisturizing part 6 is provided on the other end side of the carriage rails 51, 51, away from the conveying device 20. [ That is, the carriage 4 moves to the opposite position to the nozzle moisturizing section 6 at the other end of the carriage rails 51, 51 in the non-recording operation, and the nozzle 311 of each head 3, .

That is, the nozzle moisturizing part 6 is in close contact with the respective nozzles 311 of the nozzle plate 31 so that the inside of each nozzle is connected to the storage part of the moisturizing liquid. It is composed by mechanism.

[Ink supply device]

Fig. 4 is an explanatory diagram showing a schematic configuration of the ink supply device 8. Fig. The inkjet recording apparatus 10 has the ink supply device 8 for each color.

The ink supply device 8 includes main tanks 81 and 81 as two first tanks for storing ink and a sub tank 82 as a second tank to which ink is supplied from the main tanks 81 and 81, An intermediate tank 84 provided on the downstream side of the deaerator 83 in the ink supply direction and serving as an ink tank for temporarily storing the ink, A negative pressure forming portion 86 provided on the downstream side in the ink supply direction of the intermediate tank 84 and a first port 341 connected in parallel to each head 3 for supplying ink to each head 3 And a common flow path 87 which is formed as a whole.

In Fig. 4, the ink tray 71 of the maintenance section 7 is also shown.

The main tanks 81 and 81 are all open to the atmosphere and the two main tanks 81 and 81 are detachable from the ink jet recording apparatus 10 so that they can be replaced when they become empty have. In addition, since there are two main tanks 81 and 81, ink can be supplied from the other main tank 81 even when one side becomes empty or when it is exchanged. Therefore, the recording operation of the inkjet recording apparatus 10 is stopped Can be avoided. In addition, the number of mounted main tanks 81 may be larger.

Reference numeral 815 in Fig. 4 is a remaining amount sensor for detecting whether or not the ink in each of the main tanks 81 and 81 is empty.

The first ink channel 81 is branched between the main tanks 81 and 81 and the sub tank 82 so that one end is branched to the main tanks 81 and 81 and the other ends are joined to the sub tank 82. [ (811). In the vicinity of the main tanks 81 and 81 in the first ink passage 811, there are provided tank valves 812 and 812 as connection switching portions which are electromagnetic valves capable of switching the opening and closing states of the oil passage.

A filter 813 for removing substances such as dust and dirt from the ink is provided in the path of the sub tank 82 side of the first ink channel 811 so that the filter 813 is more sub- On the side of the tank 82, there is provided a first liquid sending pump 814 as a first liquid sending section for sending the ink to the sub tank side.

The sub tank 82 is in the form of a funnel having a side wall portion 821 whose diameter is reduced as it goes downward, and the upper portion is closed by a ceiling plate 822.

The sub tank 82 is connected to the second ink passage 823 at the center of its bottom and the ink in the sub tank 82 is supplied to the deaerator 83 side via the second ink passage 823 .

The roof plate 822 of the sub tank 82 is provided with an atmospheric release pipe 824 for keeping the inside of the sub tank 82 at atmospheric pressure. The atmospheric release pipe 824 is equipped with a filter 825 for preventing intrusion of dust, dirt, etc. from the outside.

The top end of the first ink channel 811 is connected to the top plate 822 of the sub tank 82 with the top plate 822 penetrating through the top plate 822 to the inside.

The tip portion of the first ink channel 811 extends to a position just before contact or contact with the inner surface of the side wall 822 of the sub tank 82. The ink supplied from the first ink channel 811, (822) to be poured into the liquid level in the sub tank (82).

The liquid level surveillance control of the sub tank 82 determines the liquid level upper limit position of the ink and the leading end of the first ink channel 811 is positioned at a position higher than the upper limit position of the ink liquid level on the side wall 822 Thereby supplying ink.

The ink supplied from the first ink passage 811 is always supplied to the side wall portion 822 of the sub tank 82 by setting the position of the tip end portion of the first ink passage 811 with respect to the sub tank 82 as described above. It is injected into the liquid surface through the inner surface. Thus, in the case where visually recognizable bubbles are mixed in the ink supplied from the first ink channel 811, the bubbles are mixed with the ink in the sub tank 82, As shown in FIG. In addition, since the ink flows gently along the inclined surface, new bubbles are prevented from being generated and mixed in the liquid surface of the ink.

Since the ink in the sub tank 82 is fed to the downstream side from the deepest portion through the second ink flow path 823, it is possible to remove air bubbles from the ink supplied to the downstream side of the sub tank 82 .

That is, the sub tank 82 functions as defoaming means for performing defoaming from the ink.

A first liquid level sensor 826 for defining the liquid level upper limit position of the ink in the liquid level monitoring control described later and a second liquid level sensor 827 for defining the lower liquid level position of the ink are provided in the sub tank 82 Is installed.

These liquid level sensors 826 and 827 are all float-type sensors provided with a buoy, and it is possible to detect whether the liquid level is above or below the upper or lower limit position from the height of the buoy. The liquid level monitoring control will be described later in detail.

The above-described second ink passage 823 is provided between the sub tank 82 and the degassing device 83. [ A check valve 828 for preventing ink from returning from the degassing device 83 to the sub tank 82 and a check valve 828 for preventing the ink from returning from the sub tank 82 to the degassing device 83 And a second liquid sending pump 829 as a second liquid sending section for sending ink are provided.

The degassing apparatus 83 includes a degassing module 831 to which the distal end of the second ink passage 823 is connected, a vacuum pump 832 to evacuate the degassing module 831, And a leakage valve 834 serving as an electromagnetic valve for opening the inside of the degassing module 831 to atmospheric pressure.

The degassing module 831 is configured to include a vacuum container for vacuuming by a vacuum pump 832 and a hollow capturing film for allowing ink to pass inward in the vacuum container, And is ejected outward through the caption.

The vacuum pressure sensor 833 is a detection means for measuring whether the pressure has decreased to the target pressure during vacuuming. The leakage valve 834 is connected to the control device 9 so that the deaeration module 831 is brought into the atmospheric pressure state from the vacuum state for maintenance of the deaeration module 831 when the power supply of the inkjet recording apparatus 10 is stopped. The opening control is performed.

A third ink passage 835 is provided between the degassing module 831 and the intermediate tank 84. The ink is supplied to the intermediate tank 84 by the supply pressure of the second liquid-delivery pump 829 via the second and third ink passages 823 and 835.

The intermediate tank 84 is formed by a flexible bag, and is expanded / contracted by fluctuating amount of stored ink.

The intermediate tank 84 is also provided with a liquid level sensor 841 for detecting a state in which a predetermined amount of ink is stored. When ink is supplied from the sub tank 82, the ink is supplied by the second liquid-delivery pump 829 until it is detected by the liquid level sensor 841 that the predetermined amount has been reached.

The fourth to seventh ink passages 842 to 845 are provided between the intermediate tank 84 and the negative pressure forming portion 86, and ink is supplied through the fourth to seventh ink passages 842 to 845. A first three-way switching valve 846, which is an electromagnetic switching valve, is interposed between the fourth ink channel 842 and the fifth ink channel 843 and between the fifth ink channel 843 and the sixth ink channel 844 And a third three-way switching valve 848 as an electromagnetic switching valve is interposed between the sixth ink passage 844 and the seventh ink passage 845 .

The fifth ink passage 843 is provided with a check valve 849 for allowing only the flow from the first three-way selector valve 846 to the second three-way selector valve 847 and the check valve 849 A third liquid delivery pump 850 serving as a liquid delivery section for delivering liquid in the same direction as the direction in which the liquid is supplied to the sub tank 82 and a second liquid delivery pump 850 for delivering ink to the sub tank 82 when the prescribed pressure is exceeded on the downstream side of the third liquid delivery pump 850, And a relief valve 851 for returning the relief valve 851 to the outside.

One end of the branch passage 852 is connected to the sixth ink passage 844 and the other end of the branch passage 852 is connected to the first three-way switch valve 846. The first three-way selector valve 846 is controlled by the control device 9 so that the fifth ink passage 843 is connected to the fourth ink passage 842 and the fifth ink passage 843 is branched It is possible to switch to the state of being connected to the flow path 852.

The second three-way switching valve 847 is also connected to the return flow path 853 for returning the ink to the sub tank 82. The second three-way switching valve 847 is controlled by the control device 9 The state in which the fifth ink channel 843 is connected to the sixth ink channel 844 and the state in which the fifth ink channel 843 is connected to the channel 853 can be switched.

The first and second three-way switching valves 846 and 847 are switched and controlled simultaneously by the control device 9 and the fourth, fifth and sixth ink passages 842, (A white arrow in Fig. 4) for feeding the ink to the side of the negative pressure forming portion 86 through the first to fourth ink passages 843 and 844 and the branch passage 852 from the negative pressure forming portion 86 side, Control is performed to switch the return connection state (black arrow in Fig. 4) in which the ink is fed to the sub tank 82 side through the flow path 843 and the return flow path 853.

That is, it is possible to freely and selectively perform the ink supply to the negative pressure forming portion 86 side and the ink recovery from the negative pressure forming portion 86 side using the delivery pressure of the third liquid delivery pump 850.

The third three-way switching valve 848 is also connected to a bypass flow path 854 for supplying ink to the head without passing through the negative pressure forming portion 86. Under the control of the control device 9, 844 and the seventh ink passage 845 and the state in which the sixth ink passage 844 and the bypass passage 854 are connected to each other.

That is, by this switching, supply and recovery of the ink to and from the side of the head 3 (strictly speaking, the common flow path 87) can be performed in a state in which ink supply and recovery to the negative pressure forming portion 86 can be carried out, It is possible to switch the possible states.

The negative pressure forming portion 86 includes a rectangular main body container 861 having a large opening formed in its front surface and a film member 862 including a flexible resin film for closing the opening of the main container 861, (Not shown) for pressing the center of the film member 862 outward from the inside of the film member 862.

The main body container 861 includes an eighth ink passage 863 communicating with the seventh ink passage 845 and the common passage 87 in which all the first ports 341 of the nine heads 3 are connected in parallel, Respectively.

Further, since the film member 862 presses the central portion outward by a spring, it is in a state of being in a state of being protruded outward in a substantially conical shape.

When ink is filled in the main container 861 with the same pressure as the atmospheric pressure and then the first and second three-way switching valves 846 and 847 are returned to the connected state to recover the ink from the main container 861, The inside of each of the heads 3 can be brought into a negative pressure state lower than the atmospheric pressure via the common flow path 87. The negative pressure in the interior of the head 3 can prevent the ink from leaking from the nozzle 311 when the inside of the nozzle 3 is at atmospheric pressure, It is liable to adhere and deviation of ejection failure and dot diameter easily occurs, so that this is to prevent this.

In addition, the target pressure to be a negative pressure can be controlled by adjusting the amount of ink recovered in the main container 861. [

An upper portion of the main container 861 of the negative pressure forming portion 86 is provided with a communication pipe 864 extending upwardly in communication with the main container 861. A liquid level sensor 865 is provided at the end of the communicating tube 864 on the side of the main body container 861 and a pressure sensor 866 is provided at the upper end of the communicating tube 864. A horizontally extending branch pipe 867 having one end open to the atmosphere is connected to the intermediate portion of the communicating pipe 864 and an opening valve 867 for opening and closing the branch pipe 867 is provided at an intermediate portion of the branch pipe 867, An air filter 868 for filtering air, and an air filter 869 for filtering air.

These components are used to control the ink in the main body container 861 to a predetermined negative pressure. That is, the ink is supplied into the main container 861 until the liquid level is detected by the liquid level sensor 865 with the open valve 868 opened, then the open valve 868 is closed, 866 return the target negative pressure. Thereby, the inside of each head 3 can be brought into a predetermined negative pressure state through the negative pressure forming portion 86.

The eighth ink passage 863 extending from the negative pressure forming portion 86 joins the bypass passage 854 described above and is connected to the common passage 87. A protective valve 871, which is an electromagnetic valve of normally open type, is provided on the side of the negative pressure forming portion 86 than the junction point of the eighth ink passage 863 with the bypass passage 854.

The common flow path 87 is an inner hollow container in the shape of a flat plate whose shape is a substantially isosceles triangle (exactly, a quadrangular shape formed by cutting both ends of the isosceles triangle bottom side along the vertical direction) as viewed from the front, And is mounted on the carriage 4 so that the bottom surface is level. The common flow path 87 is connected to the eighth ink flow path 863 at a portion corresponding to the apex of the isosceles triangle and is connected to the first port of nine heads 3 of the same color at portions corresponding to the base of the isosceles triangle (341) are connected in parallel.

The common flow path 87 passes through the inner space formed by solidifying the shape of the substantially triangular shape same as the outer shape. At this time, since the ink is supplied from the position of the vertex, the ink is uniformly supplied to each head 3 connected to the corner of the bottom without causing large deviations.

The shape of the common flow path 87 as viewed from the front face of the inner space to which the ink is supplied may be a substantially isosceles triangle, and the shape of the outer flow path may not be substantially isosceles triangle.

In addition, a waste liquid flow path 872 as a discharge path communicating with a waste liquid tank (not shown) is connected to the vicinity of the peak position of the common flow path 87. The waste liquid flow path 872 is provided with a waste liquid valve 873 which is a normally closed type electromagnetic valve. When the common flow path 87 is filled with ink, the waste liquid valve 873 is opened to discharge ink . Since the waste liquid flow path 872 is connected to the apex of the upper end of the common flow path 87, the bubbles float upward in the common flow path 87 by supplying the ink again with the common flow path 87 filled with ink And is efficiently discharged together with the ink. As a result, the bubbles which cause the ejection failure of the ink can be removed, and stable ejection can be performed.

5 is an explanatory view showing the connection state between the common flow path 87 and each head 3. As shown in Fig. As shown in Figs. 4 and 5, the common flow path 87 is connected to the first port 341 of each head 3 via a recording operation valve 874, which is an electromagnetic valve of normally open type.

The second ports 342 of the respective heads 3 are connected in parallel to the common waste liquid flow path 876 via maintenance valves 875 of normally closed type. The common waste liquid flow path 876 joins the waste liquid flow path 872 on the downstream side of the waste liquid valve 873 and is connected to the waste liquid tank.

Since the ink discharged from the waste liquid flow path 872 mainly aims to discharge the bubbles in the common flow path 87, only the waste liquid flow path 872 is not merged with the common waste liquid flow path 876, 82 to allow reuse of the ink. In this case, the common waste liquid flow path 876 is connected to the waste liquid tank alone.

[controller]

Fig. 6 is a block diagram showing the control system of the ink supply device 8. Fig. The control device 9 shown in Fig. 6 controls the entire inkjet recording apparatus 10, but only the configuration of the ink supply device 8 is shown here, and other configurations are omitted. In addition, only one of the plural components is shown.

The control device 9 controls the control of the ink supply device 8 such as converting the image data of the image to be recorded on the recording medium inputted from the external device into data corresponding to the respective nozzles 311 of the head 3, In addition, the driving of each section of the inkjet recording apparatus 10 is also controlled.

6, the control device 9 includes a CPU 91, a ROM 92, a RAM 93, an input / output interface (not shown), and a general-purpose computer connected to the bus.

The control device 9 is provided with first to third liquid delivery pumps 814, 829 and 850, a vacuum pump 832, a tank valve 812, a leakage valve 834, first to third three- 846, 847 and 848, a release valve 868, a protection valve 871, a waste liquid valve 873, a recording operation valve 874 and a maintenance valve 875 are connected to the control device 9 And these are controlled objects.

The control device 9 is also provided with a remaining amount sensor 815, first and second liquid level sensors 826 and 827, a liquid level sensor 841, a liquid level sensor 865, a vacuum pressure sensor 833, 866 are connected, and various detection signals are input from them.

The control unit 9 is also connected with an input operation unit 94 for performing support input such as execution of various operations from the operator and a display unit 95 for displaying various information such as error information.

Then, the control device 9 performs liquid level monitoring control of the sub tank 82, maintenance control of the head 3, and the like, for each of the control objects in accordance with these detection information.

[Level monitoring control]

The liquid level monitoring control of the sub tank 82 performed by the control device 9 will be described in detail with reference to the flowchart of FIG.

This liquid level monitoring control is a control for supplying ink from the main tank 81 of the ink to the sub tank 82 and for maintaining and maintaining a constant amount of ink in the sub tank 82, .

In this liquid level monitoring control, it is premised that either one of the tank valves 812 of the main tanks 81 and 81 is opened and the other tank valve 812 is closed.

The control device 9 first initializes a timer counter for determining whether the main tank 81 connected to the present sub tank 82 is empty (step S1).

Subsequently, it is judged by the first liquid level sensor 826 whether or not the detection level of the first liquid level sensor 826 indicating that the ink in the sub tank 82 is full (step S3).

As a result, when it is detected that the ink has reached the detection level by the first level sensor 826, the ink in the sub tank 82 has reached the target amount, so the control device 9 ends the level monitoring control .

On the other hand, when it is detected that the ink has not reached the detection level by the first liquid level sensor 826, the timer for counting the timer for determining whether the main tank 81 is empty is started and the first liquid sending pump 814 To operate the ink supply from the main tank 81 to the sub tank 82 (step S5).

Subsequently, the control device 9 determines whether or not the second level sensor 827 reaches the detection level of the second level sensor 827 indicating that the ink in the sub tank 82 is almost empty (step S7).

As a result, when it is detected that the ink has reached the detection level by the second liquid level sensor 827, the control device 9 determines whether or not the time of counting by the timer has passed the predetermined feeding time (step S9).

When the time counted by the timer does not pass the predetermined feeding time, the process returns to step S3 to determine whether or not the sub tank 82 is full.

The liquid delivery time in the determination of the step S9 is set to a time sufficient to fill the sub tank 82 with the liquid delivery ability of the first liquid delivery pump. That is, when the sub tank 82 is not filled up even after the lapse of time, it is assumed that the main tank 81 is already empty.

Therefore, the control device 9 stops driving the first liquid-delivery pump 814 (step S11), determines that the main tank 81 is empty (step S13), and controls the tank valve 812, And the other tank valve 812 is opened to switch the main tank for supplying ink to the sub tank 82 (step S15). At this time, display control may be performed to notify the display unit 95 that one of the main tanks 81 is vacant.

After switching the main tank 81, the control device 9 again returns the process to step S1 to resume ink supply to the sub tank 82. [

When the empty state of the sub tank 82 is detected by the second liquid level sensor 827 in step S7 (step S7: "NO"), even if the liquid is supplied to the first liquid-delivery pump 814, The controller 9 indicates that all the tanks 81 and 81 are in an empty state and all of the ink in the main tanks 81 and 81 and the sub tank 82 are being used up, All recording operations of the inkjet recording apparatus 10 are stopped in the recording operation to prevent the occurrence of defects. At this time, display control may be performed on the display unit 95 to display a notification indicating that an error has occurred and a warning indicating that ink is empty.

[Maintenance control (for some heads)]

The maintenance control of the head 3 performed by the control device 9 will be described in detail with reference to the flowchart of Fig. Here, it is assumed that the ejection test is performed on the entire head 3 in advance to specify the head 3 that needs maintenance, and that the input operation of the head 3 to be maintenance- .

Further, it is assumed that the carriage 4 is standing just above the maintenance section 7.

First, the control device 9 switches the first and second three-way switching valves 846 and 847 to the supply connection state (connection of the white arrow in Fig. 4) To be connected to the bypass flow path 854 from the ink flow path 844 (step S21).

The control device 9 also controls the waste fluid valve 873 of the common flow path 87 to be closed and the protection valve 871 to close so as to close the recording operation valve 874 of the entire head 3 (Step S23).

Then, the liquid delivery control of ink is executed (step S25).

Here, the pumping control will be described with reference to the flowchart of Fig.

At the time of pumping, the control means actuates the third liquid-delivery pump 850 (step S251), and makes a determination as to whether or not the operation time T1 has elapsed in advance (step S253) Lt; RTI ID = 0.0 > 850 < / RTI >

The ink in the intermediate tank 84 bypasses the negative pressure forming portion 86 and is directly supplied to the common flow path 87 by the operation of the third liquid feed pump 850. [ At this time, since the recording operation valve 874 of the entire head 3 is closed and the maintenance valve 875 is a normally closed valve, no ink is supplied to each of the heads 3, ) Is filled with ink. Further, when ink is filled in the common flow path 87, surplus ink is discharged from the waste liquid flow path 872. The bubbles in the common flow path 87 float up to the upper portion of the common flow path 87 and are discharged from the waste liquid flow path 872.

When the operation time T1 has elapsed, the third liquid feed pump 850 is stopped (step S255), and the process waits until the waiting time T2 elapses. As a result, bubbles generated by being injected into the common flow path 87 float up to the upper portion in the common flow path 87 and are collected.

When the waiting time T2 has elapsed, the controller 9 determines whether the number of repetitions of the supply of the ink and the waiting has reached the preset target number N (step S259).

If the target number of times has not been reached, the process returns to step S251, and the supply of the ink and the wait are executed again.

Further, the operation time T1, the waiting time T2, and the target number of times N can be set to the control device 9 by the input operation unit 94 in advance. It is preferable that the target number N of repetition is set to be at least two or more times so that bubbles floating above the common flow path 87 by the atmosphere can be discharged from the next ink supply.

Returning to Fig. 8, description will be given again.

The control device 9 closes the waste liquid valve 873 of the common flow path 87 (step S27), and the recording operation valve 874 of the maintenance target head 3 and the maintenance valve 873 (Step S29).

Then, the liquid delivery control is executed again (step S31). At this time, the operation time T1, the waiting time T2, and the target number of times N may be the same values as in step S25, or may be set to different values.

In this case, ink is supplied from the common flow path 87 to the maintenance target head 3 via the first port 341. The supplied ink is discharged to the common waste liquid flow path 876 through the second port 342 and part of the ink is also discharged from the nozzle 311 of the head 3 to the ink tray 71. [

When the second pumping control is completed, the control device 9 closes the maintenance valve 875 of the head 3 to be maintained (step S33).

Then, the third pumping control is executed (step S35). At this time, the operation time T1, the waiting time T2, and the target number of times N may be the same values as in step S25 or S31, or may be set to different values.

Ink is supplied from the common flow path 87 to the maintenance target head 3 through the first port 341 and is discharged from the nozzle 311 to the ink tray 71. In this case, At this time, since the supply pressure of the ink acts on the discharge from all of the nozzles 311, it is possible to push out the foreign substance or the like even on the nozzle 311 which has been clogged, for example, to solve the clogging.

When the third pumping control is completed, the control device 9 also releases all the recording operation valves 874 of all the heads 3 other than the head 3 to be maintained (step S37) The third three-way switching valve 848 is switched to the state in which the sixth ink passage 844 and the seventh ink passage 845 are connected (step S39).

Then, the control device 9 executes the negative pressure forming portion back pressure adjustment control (Step S41), and further performs the wiping control of each head 3 to end the maintenance control (Step S43).

Here, the negative pressure forming portion back pressure adjustment control will be described in detail with reference to the flowchart of FIG.

First, the controller 9 opens the open valve 868 and closes the protective valve 871 (step S411).

Subsequently, the current pressure of the pressure sensor 866 in the negative pressure forming portion 86 is set to the atmospheric pressure (Step S412).

Subsequently, the operation of the third liquid feed pump 850 is started (step S413), and the ink supplied into the main container 861 of the negative pressure forming portion 86 is guided to the liquid level sensor 865 located at the upper end of the main container 861 (Step S414).

If the ink does not reach the upper end of the main container 861, the ink supply to the main container 861 is continued. When the ink reaches the upper end of the main container 861, the third feed pump 850 is stopped (Step S415).

Thereafter, the control device 9 closes the opening valve 868 (step S416) and switches the first and second three-way switching valves 846 and 847 to the return connection state (the black arrow in Fig. 4) (Step S417).

When the third liquid feed pump 850 is operated again (step S418), the ink inside the main container 861 of the negative pressure forming portion 86 is discharged. As a result, the internal pressure of the main body container 861 is lowered.

When it is detected by the pressure sensor 866 that the pressure is lowered to the negative pressure pressure value suitable for ink ejection (step S419), a negative pressure value suitable for ink ejection of each head 3 is determined, 3 The liquid feed pump 850 is stopped (step S420).

The control device 9 opens the protection valve 871 (step S421) and thereby the negative pressure forming portion 86 and each head 3 move the eighth ink passage 863 and the common passage 87 Respectively. As a result, the inside of each head 3 becomes the same negative pressure as the inside of the negative pressure forming portion 86.

Thereafter, the control device 9 performs control to switch the first and second three-way switching valves 846 and 847 to the supply connection state (white arrow in Fig. 4) (step S422) And ends the adjustment control.

The wiping control will be described based on the flowchart of Fig. In the wiping control, wiping around the respective nozzles 311 is performed with respect to the entire head 3 on the carriage 4.

The wiping of each nozzle 311 is performed by conveying the wiping roller for performing rotational drive around the rotation axis along the X axis direction along the Y axis direction while sliding on the lower face of the nozzle plate 31.

On the other hand, in the inkjet recording apparatus 10, since nine heads 3 are mounted for each of nine colors on the carriage 4, the area for wiping is also very large. Therefore, if the wiping roller is to be completed by one-way transfer, the wiping roller must be elongated in the direction of the rotational axis, and warping or the like is liable to occur, thereby making it impossible to perform effective wiping.

Therefore, the wiping roller is wiped with respect to the nozzles of the entire head 3 for nine colors by dividing the wiping roller into three portions in the X-axis direction so as to have the same size as the array width of the heads 3 for the three colors .

The operation control will be described below.

First, the control device 9 rotates the wiping roller and carries out a one-minute amount (round trip) from its standby position (step S431). As a result, wiping is performed on the head 3 for three colors.

Then, the carriage 4 is moved by a distance equal to the width in the X-axis direction of the arrangement of the heads 3 for the three colors (step S433), and the one-way delivery (return) is carried out while rotating the wiping roller Step S435). As a result, wiping is performed on the head 3 of the next three colors.

The carriage 4 is moved by the same distance as the width of the arrangement of the heads 3 for three colors in the X axis direction (step S437), and the one-way division (forward path) is carried out while rotating the wiping roller S439). Thereby, wiping is performed on the head 3 of the last three colors.

The wiping is repeatedly performed a predetermined number of times. Therefore, when the wiping for nine colors is completed, the control device 9 compares the execution number of the current wiping with the preset repetition number (step S441). As a result, if the current execution number does not reach the set repetition number, the process returns to S431 to start the wiping operation again.

On the other hand, if the current execution count matches the setting repeat count, the wiping control is terminated.

12A is a view showing a state in which the liquid delivery control in step S35 in the maintenance control of Fig. 8, that is, the recording operation valve 874 connected to the maintenance target head 3 is opened and the maintenance valve 875 is closed In the case where the supply pressure in the feed in one state is changed stepwise. The supply pressure of the ink is made by PWM control of the motor which is the driving source of the third feed pump 850. [

As shown in the drawing, when the supply pressure is 10 [kPa], the ejection failure is not caused but the complete recovery does not occur. When the supply pressure is 20 [kPa], the ejection becomes good and when the feed pressure is 30 and 40 [kPa] And was recovered to such an extent that a better discharge was made. That is, in order to recover the clogging of the nozzle 311, it is preferable to perform maintenance by supplying ink at 30 [kPa] or more.

12B is a view showing a state in which the liquid delivery control in step S31 in the maintenance control in Fig. 8, that is, both the recording operation valve 874 and the maintenance valve 875 connected to the maintenance target head 3 are opened And Fig. 4 is a chart showing the bubble removal situation in the head 3 when the supply pressure in the feed in one state is changed stepwise.

As shown in the figure, when the supply pressure is 3 [kPa], bubbles in the head 3 can not be sufficiently discharged, and when 4 [kPa] and 5 [kPa] are set, some bubbles are discharged, The air bubbles in the head 3 are sufficiently discharged when the air bubbles are left in the head 3 and the air bubbles are left in the head 3 at 7 kPa and 9 kPa, 3) were discharged more fully. That is, in order to discharge the bubbles in the head 3, it is preferable to perform maintenance by supplying ink at 7 [kPa] or more.

[Maintenance control (for all heads)]

Next, the maintenance control of the entire head 3 performed by the control device 9 will be described in detail with reference to the flowchart of Fig.

The control device 9 controls the first and second three-way switching valves 846 and 847 to be in a supply connection state (connection with a white arrow in Fig. 4) ), And connects the third three-way switching valve 848 to the bypass flow path 854 (step S51).

The waste liquid valve 873 of the common flow path 87 is opened and the protection valve 871 is closed so that the recording operation valve 874 of the entire head 3 is closed (step S53).

9) is executed (step S55), and the bubbles in the common flow path 87 are discharged together with the ink.

The control device 9 closes the waste liquid valve 873 of the common flow path 87 (step S57), and the recording operation valve 874 and the maintenance valve 875 of all the heads 3 (Step S59).

Then, the second pumping control is executed (step S61). When bubbles and inclusion in each head 3 are present, the liquid is discharged from the nozzle 311 and the second port 342 to the outside.

When the pumping control is completed, the control device 9 closes the maintenance valve 875 of all the heads 3 (step S63).

10) (step S65), and the wiping control (see Fig. 11) of each head 3 is executed to terminate the maintenance control (Step S67).

[Technical Effect in Embodiments of the Invention]

The inkjet recording apparatus 10 has nine heads 3 for the same color and the manifold 34 of each head 3 has first and second ports 341 and 342 communicating therewith At the same time, a flow path following each of the first and second ports 341 and 342 is provided with a recording operation valve 874 and a maintenance valve 875 for performing opening / closing switching control by the control device 9.

This allows the first port 341 and the second port 342 to be individually opened and closed with respect to an arbitrary head 3 under the control of the control device 9, It is possible to return from the clogging due to the discharge of the mixed substance in the head 3 and to discharge the bubbles to only the part of the head 3 which is the head 3.

This makes it possible to reduce the amount of ink consumed due to maintenance.

Further, since the amount of ink consumption can be reduced without collecting the ink used for maintenance, it is not necessary to equip each head with a filter in order to collect the ink, and the inspection work of the filter is also unnecessary.

In addition, as compared with the case where maintenance is performed by connecting all the heads in series, the maintenance can be performed only on a part of the heads 3 to be maintained, so that the required time can be greatly shortened.

Since the ink jet recording apparatus 10 has the common flow path 87 for connecting the heads 3 in parallel, unlike the case where a plurality of heads are connected in series, It does not move into the other head 3. Further, for example, the pressure adjustment in each head 3 can be performed at once with respect to the entire head 3 by way of this common flow path 87. [

In addition, when the waste liquid flow path 872 for discharging the ink inside the common flow path 87 is provided, the bubbles generated in the common flow path 87 can be easily discharged from the waste liquid flow path 872.

Further, since the negative pressure forming portion 86 and the bypass passage 854 are provided, even when a pressure higher than a normal pressure is applied to any one of the heads 3 during maintenance, Closing of the third three-way switching valve 848 and the protection valve 871 located in the first and second three-way switching valves 848 and 871, the influence of the pressure can be avoided and the negative pressure forming portion 86 can be protected.

[Other]

In the above embodiment, the shape of the common flow path 87 is a substantially isosceles triangular flat plate shape when viewed from the front, but the shape thereof is not limited thereto.

Figs. 14A to 14C show modified examples of the common flow path 87. Fig. The common flow path 87A of this modified example has a rectangular shape whose long side is parallel to the Y-axis direction in the shape seen from the front side, and is formed in a rectangular parallelepiped shape as a whole. The inside is hollow, and the inside space has the same shape as the outside shape.

Unlike the above-described common flow path 87, the common flow path 87A has a flat top. The waste liquid flow path 872 is connected at substantially the same height as the inner top surface of the common flow path 87A, and allows bubbles to collect at the top of the common flow path 87A during maintenance.

14A to 14C show the case where the eighth ink passage 863 for supplying ink to the common passage 87 is connected to the right end portion, the left end portion and the center portion of the common passage 87A. As described above, since the common flow path 87A is rectangular in plan view, the connection position of the eighth ink flow path 863 can be appropriately selected.

≪ Industrial applicability >

There is a possibility in the field of an ink jet recording apparatus that ejects ink from a plurality of heads for one color.

3: Head
9: Control device (control section)
10: ink jet recording apparatus
34: Manifold
341: First port
342:
8: ink supply device
81: Main tank (first tank)
811: first ink channel
812: Tank valve (connection switching part)
814: first liquid sending pump (first liquid feeding section)
82, 82A and 82B: sub tank (second tank)
829: Second liquid delivery pump (second delivery section)
83: Deaerator
84: Medium tank (ink tank)
848: Third three-way switching valve (valve)
850: Third pump (pump)
854: Bypass Euro
86: Negative pressure forming part
87:
871: Protection valve (valve)
872: Waste liquid flow path (discharge flow path)
873: Waste liquid valve (valve)
874: Recording action solenoid valve (valve)
875: Maintenance valve (valve)

Claims (10)

A plurality of heads for ejecting ink of the same color on a recording medium,
An ink tank for storing ink to be supplied to each of the plurality of heads,
And a liquid delivering section for sending ink from the ink tank to the head side,
Wherein each of the heads has a manifold in which ink is filled, a first port communicating with the manifold and supplying ink to each head, and a second port communicating with the manifold and discharging ink from each head Have,
A valve capable of opening and closing switching is provided in an ink flow path leading to each of the first port and the second port of each head,
A common flow path in which all the first ports of the heads are connected in parallel through the valve,
A discharge flow path connected to the common flow path for discharging the ink inside the common flow path,
An openable and closable valve provided in the discharge passage,
And a control unit for individually controlling the opening and closing of the valves following each of the first and second ports of each of the heads and controlling the opening and closing of the valves of the discharge channel,
Ink is supplied to each of the heads through the common flow path,
The control unit opens the valve leading to the first port of the maintenance target head among the plurality of heads and closes the valve following the second port, A first maintenance operation for performing maintenance by supplying ink to the head to be maintained by the liquid delivering unit in a closed state,
The valve leading to the first port and the valve leading to the second port of the head to be subjected to maintenance among the plurality of heads are opened by the control unit and the valve leading to the first port of the remaining head is closed And a second maintenance operation for performing maintenance by supplying ink to the head to be maintained by the liquid delivering section,
Wherein the control unit discharges the ink in the common flow path to the discharge flow path by opening the valve of the discharge flow path in a state in which the valve of the first port of all the heads is closed. delete delete delete The ink jet recording head according to claim 1, wherein a negative pressure forming portion for holding the inside of each of the heads in a negative pressure state lower than the atmospheric pressure is provided in common in the respective ink heads from the ink tank to the heads,
A bypass flow path for supplying ink without passing through the negative pressure forming section,
Wherein an opening / closing switchable valve for blocking the pressure at the time of ink supply is provided before and after the negative pressure forming portion. The ink cartridge according to any one of claims 1 to 5, wherein the supply pressure of the ink by the liquid delivering portion in the first maintenance operation is equal to or more than the supply pressure of the ink by the liquid delivering portion in the second maintenance operation And the ink jet recording head is set to be in a non-ejecting state. The ink cartridge according to any one of claims 1 to 5, wherein a filter for partitioning a region on the side communicating with the first port and the second port and a region on the side communicating with the nozzle for discharging ink is provided inside the manifold The inkjet recording apparatus comprising: The ink cartridge according to claim 1 or 5, wherein a second ink tank is provided on an upstream side of the ink tank in the ink supply direction, and a deaeration (deactivation) of the ink is provided in the middle of the ink channel from the second ink tank to the ink tank Wherein a degassing module for performing a degassing process is provided on the downstream side. The vacuum degassing apparatus according to claim 8, wherein the degassing module includes a vacuum container for vacuuming by a vacuum pump, and a hollow capturing membrane (hollow film) for allowing ink to pass inward in the vacuum container, And the dissolved gas in the ink is ejected outward through the hollow caption membrane to perform the deaeration of the ink. The ink-jet recording apparatus according to claim 1 or 5, further comprising specifying means for specifying a head to be subjected to maintenance among the plurality of heads.

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