JP2009208232A - Fluid ejection device and maintenance method for fluid ejection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid ejection device capable of preventing missing dot, and a maintenance method for the fluid ejection device. <P>SOLUTION: The fluid ejection device includes an ejection head having a plurality of nozzle openings for ejecting fluid and a fluid holding part connected to the plurality of nozzle openings and holding the fluid, and a fluid supply part connected to the fluid holding part and capable of supplying the fluid to the plurality of nozzle openings independently, and further includes a control part performs control to supply the fluid to the plurality of nozzle openings so as to form a convection current of the fluid in a predetermined direction inside the fluid holding part during maintenance of the ejection head, and to discharge the fluid in the fluid supply part to the nozzle opening side after forming the convection current. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fluid ejecting apparatus and a maintenance method for the fluid ejecting apparatus.

  As a fluid ejecting apparatus that ejects a fluid, for example, an ink jet recording apparatus is known. An ink jet recording apparatus is an apparatus that records characters, images, and the like on a medium, and is configured to eject ink onto the medium from a plurality of nozzle openings provided in a recording head. Inside the recording head, a reservoir (cavity) connected to a plurality of nozzle openings is provided. The reservoir is connected to an external ink supply source such as an ink cartridge, and holds ink supplied from the ink supply source.

In the recording head configured as described above, bubbles may accumulate in the vicinity of the nozzle openings or in the reservoir, and if the bubbles block the ink flow path of the nozzle openings and the reservoir, it causes dot dropout. On the other hand, a cleaning method has been proposed in which bubbles are discharged by ejecting a predetermined amount of ink from a nozzle opening (see, for example, Patent Document 1).
JP 55-71567 A

  However, for a large recording head or the like in which a large number of nozzle openings are arranged, for example, it is difficult to apply pressure uniformly in the reservoir because the volume of the reservoir is large. For this reason, distribution of ink flow occurs when ink is ejected during leaning. Due to the distribution of the ink flow, the bubbles are caused to flow in a weak flow portion. The ink in the reservoir is easy to be supplied to the nozzle opening in the portion where the flow is strong, and is difficult to be supplied in the portion where the flow is weak. As a result, bubbles remain in the reservoir. Since the bubbles block the ink supply path to the nozzle openings, the ink is not ejected from the nozzle openings, and dots are lost. Even if the recording head is not a large recording head, in a recording head provided with a plurality of nozzle openings, the ink flow in the reservoir may be distributed, and the same problem can be considered.

  In view of the circumstances as described above, an object of the present invention is to provide a fluid ejecting apparatus and a fluid ejecting apparatus maintenance method capable of preventing dot dropout.

  In order to achieve the above object, a fluid ejection device according to the present invention includes a ejection head having a plurality of nozzle openings that eject fluid, a fluid holding unit that is connected to the plurality of nozzle openings and retains the fluid, and the fluid retention A fluid supply device connected to a plurality of nozzle openings and capable of supplying the fluid independently to a plurality of the nozzle openings, wherein the fluid holding unit is maintained in a predetermined direction during maintenance of the ejection head. The apparatus further includes a control unit configured to supply the fluid to the plurality of nozzle openings so that fluid convection is formed, and to discharge the fluid in the fluid supply unit to the nozzle opening side after the formation of the convection. To do.

  According to the present invention, at the time of maintenance of an ejection head including a plurality of nozzle openings and a fluid holding unit, the control unit allows fluid to be formed in the plurality of nozzle openings so that convection of fluid is formed in a predetermined direction in the fluid holding unit. Therefore, even when the fluid flow is distributed in the fluid holding portion, the bubbles can be moved in a predetermined direction by the convection. Further, since the fluid in the fluid supply unit is discharged to the nozzle opening side after the convection is formed by the control unit, the moved bubbles can be easily discharged together with the fluid. Thereby, it is possible to prevent bubbles from remaining in the fluid holding portion, and it is possible to prevent missing dots.

  Note that the “predetermined direction” can be a direction from a location where the fluid flow rate is low to a location where the flow rate is high, for example, in a normal fluid ejection in the fluid holding unit. In this case, since the bubbles move to a location where the fluid flow rate is fast, the bubbles can be easily discharged by ejecting the fluid during maintenance. Further, examples of the “predetermined direction” include a direction from one end to the other end in the fluid holding unit. In this case, since the bubbles move to the other end portion in the fluid holding portion, the bubbles can be easily discharged by intensively discharging the fluid from the other end portion during maintenance.

In the fluid ejecting apparatus, the control unit causes the fluid to be supplied to the nozzle opening provided at a position where the fluid flows by the convection among the plurality of nozzle openings.
According to the present invention, the control unit controls the fluid supply unit so that the fluid is supplied to the nozzle opening provided at the position where the fluid flows by convection among the plurality of nozzle openings. Bubbles are discharged together with the fluid from the nozzle opening at the position. Thereby, compared with the case where fluid is discharged from all nozzle openings, the amount of fluid discharged can be suppressed.

The fluid ejecting apparatus further includes a suction mechanism that is provided so as to be able to seal a space including the plurality of nozzle openings, and the control unit causes the suction mechanism to suck the space so that the fluid is sucked. Is discharged to the nozzle opening side.
According to the present invention, a space including a plurality of nozzle openings can be hermetically sealed, and further includes a suction mechanism that sucks the space, and the controller causes the suction mechanism to suck the space to discharge the fluid to the nozzle openings. Therefore, the bubbles are discharged together with the fluid from the nozzle opening where the bubbles have moved. Thereby, it can prevent reliably that a bubble remains in a fluid holding | maintenance part.

  A fluid ejection apparatus maintenance method according to the present invention includes: a plurality of nozzle openings that eject fluid; an ejection head that is connected to each of the plurality of nozzle openings and includes a fluid holding section that holds the fluid; and the fluid holding section. A fluid ejecting apparatus maintenance method comprising: a fluid supply unit that is connected and capable of supplying the fluid independently to a plurality of the nozzle openings, wherein convection of the fluid is formed in a predetermined direction in the fluid holding unit. The fluid is supplied to the plurality of nozzle openings as described above, and the fluid in the fluid supply section is discharged to the nozzle opening side after the formation of the convection.

  According to the present invention, at the time of maintenance of an ejection head including a plurality of nozzle openings and a fluid holding unit, fluid is supplied to the plurality of nozzle openings so that convection of fluid is formed in a predetermined direction in the fluid holding unit. Therefore, even when the fluid flow is distributed in the fluid holding portion, the bubbles can be moved in a predetermined direction by the convection. Moreover, since the fluid in the fluid supply unit is discharged to the nozzle opening side after the convection is formed, the moved bubbles can be easily discharged together with the fluid. Thereby, it is possible to prevent bubbles from remaining in the fluid holding portion, and it is possible to prevent missing dots.

The maintenance method of the fluid ejecting apparatus is characterized in that the fluid is supplied to the nozzle opening provided at a position where the fluid flows by the convection among the plurality of nozzle openings.
According to the present invention, since the fluid is supplied to the nozzle opening provided at the position where the fluid flows by convection among the plurality of nozzle openings, the bubbles are discharged together with the fluid from the nozzle opening at the position where the bubbles have moved. It will be. Thereby, compared with the case where fluid is discharged from all nozzle openings, the amount of fluid discharged can be suppressed.

In the maintenance method for the fluid ejecting apparatus, the fluid ejecting apparatus further includes a suction mechanism that can seal the space including the plurality of nozzle openings and sucks the space, and causes the suction mechanism to suck the space. Thus, the fluid is discharged to the nozzle opening side.
According to the present invention, the fluid ejecting apparatus is further provided with a suction mechanism that can seal a space including a plurality of nozzle openings and sucks the space, and the suction mechanism sucks the space to discharge the fluid to the nozzle opening side. Therefore, the bubbles are discharged together with the fluid from the nozzle opening where the bubbles have moved. Thereby, it can prevent reliably that a bubble remains in a fluid holding | maintenance part.

  Hereinafter, an embodiment of a fluid ejection device and a maintenance method for a fluid ejection device according to the present invention will be described with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size. In this embodiment, an ink jet printer is exemplified as the fluid ejecting apparatus according to the invention.

FIG. 1 is a schematic configuration diagram of an ink jet printer (hereinafter referred to as an ink jet printer 100) of the present embodiment, FIG. 2 is a plan view of a main part around a line head, and FIG. FIG.
As shown in FIGS. 1 and 2, in this embodiment, the inkjet printer 100 includes a recording unit 10 that performs recording on the recording paper 12 and a maintenance unit 11 that performs maintenance processing on the recording unit 10.

  The recording unit 10 ejects ink droplets to form a line head 13 (ejection head) that forms an image on a recording paper 12 that is a fluid ejection target, a recording paper conveyance mechanism 14 that conveys the recording paper 12, and a line head 13. An ink storage unit 15 that stores ink (fluid) to be supplied.

  The recording paper transport mechanism 14 includes a paper feed motor (not shown), a paper feed roller that is rotationally driven by the paper feed motor, and the like, and the recording paper 12 is fed in conjunction with a recording (printing / printing) operation. Sequential feeding can be performed so as to face the line head 13.

  The ink storage unit 15 is disposed on one side of the printer main body 16 and supplies ink to the line head 13 described later by an ink supply unit (not shown). This ink storage unit 15 is an ink of a color corresponding to each color (yellow (Y), magenta (M), cyan (C), black (K1: dye system), black (K2: pigment system)) of the inkjet printer 100. Ink tanks 15Y, 15M, 15C, 15K1, and 15K2. The ink reservoir 15 and the line head 13 communicate with each other via an ink supply unit.

  The line head 13 is a line type recording head in which a number of nozzles are arranged over a length (maximum recording paper width W) exceeding at least one side of the maximum size recording paper 12 targeted by the inkjet printer 100. In the present embodiment, at least five printing sections 5Y, 5M, 5C, 5K1, and 5K2 corresponding to each color (Y, M, C, K1, and K2) are provided. Each of the printing units 5Y, 5M, 5C, 5K1, and 5K2 has a nozzle row L (see FIG. 3) in which a large number of nozzle openings 17 for ejecting ink droplets are arranged and arranged. The region in which is formed is the nozzle region 21B. The nozzle rows L are arranged in order along the conveyance direction of the recording paper 12. The nozzle row L is one row line by the nozzle openings 17 or a plurality of lines by the nozzle openings 17, and the number of nozzle openings 17 and the number of lines are appropriately set. FIG. 3 shows an embodiment of the nozzle row L, and shows a plurality of lines by the nozzle openings 17. By increasing the number of lines, a wide range of recording can be performed at once, and the resolution of the image is also increased.

The line head 13 is arranged such that the length direction corresponding to the maximum recording paper width W is perpendicular to the conveyance direction of the recording paper 12, and ink droplets are ejected from the nozzle openings 17 of the nozzle rows L onto the recording paper 12. Thus, an image is recorded on the recording paper 12.
The ink supply means for communicating the ink reservoir 15 and the line head 13 has a plurality of ink supply channels 34 (see FIG. 5), and prints from the ink tanks 15Y, 15M, 15C, 15K1, and 15K2. Ink is supplied to the sections 5Y, 5M, 5C, 5K1, and 5K2.

Hereinafter, the configuration of the line head will be described in detail with reference to FIG. FIG. 4 is a cross-sectional view showing a part of the line head.
The line head 13 includes a head main body 18 and a flow path forming unit 22 including a vibration plate 19, a flow path substrate 20, and a nozzle substrate 21. The nozzle openings 17 for ejecting ink are formed in the nozzle substrate 21, and the lower surface of the nozzle substrate 21 is a nozzle formation surface 21A. The flow path forming unit 22 is a unit in which the diaphragm 19, the flow path substrate 20, and the nozzle substrate 21 are laminated and joined together with an adhesive or the like.

  The line head 13 includes an accommodation space 23 formed inside the head body 18 and a drive unit 24 disposed in the accommodation space 23. The drive unit 24 includes a plurality of piezoelectric elements (fluid supply units) 25, a fixing member 26 that supports the upper end of the piezoelectric elements 25, and a flexible cable 27 that supplies a drive signal to the piezoelectric elements 25. The piezoelectric element 25 is provided so as to correspond to each of the plurality of nozzle openings 17.

  In addition, an internal flow path 28 that is formed inside the head body 18 and flows ink supplied from the ink tank via the ink supply flow path, and a flow path that includes the vibration plate 19, the flow path substrate 20, and the nozzle substrate 21. A reservoir 29 formed by the forming unit 22 and connected to the internal flow path 28, an ink supply port 30 formed by the flow path forming unit 22 and connected to the reservoir 29, and an ink formed by the flow path forming unit 22 A cavity 31 connected to the supply port 30 is provided. A plurality of cavities 31 are provided so as to correspond to the plurality of nozzle openings 17. Each of the plurality of nozzle openings 17 is connected to each of the plurality of cavities 31.

  The head body 18 is made of synthetic resin. The diaphragm 19 is obtained by laminating an elastic film on a metal support plate such as stainless steel. An island portion 32 to be joined to the lower end of the piezoelectric element 25 is formed at a portion corresponding to the cavity of the diaphragm 19. At least a part of the diaphragm 19 is elastically deformed according to the driving of the piezoelectric element 25. A compliance portion 33 is formed between the diaphragm 19 and the vicinity of the lower end of the internal flow path 28.

  In the flow path substrate 20, the reservoir 29, the ink supply port 30, and the cavity 31 that connect the lower end of the internal flow path 28 and the nozzle opening 17 have recesses for forming respective spaces. In the present embodiment, the flow path substrate 20 is formed by anisotropic etching of silicon.

  The nozzle substrate 21 has a plurality of nozzle openings 17 formed at predetermined intervals (pitch) in a predetermined direction. The nozzle substrate 21 of the present embodiment is a plate-like member formed of a metal such as stainless steel.

  The ink supplied from each ink tank through each ink supply channel flows into the upper end of the internal channel 28. The lower end of the internal flow path 28 is connected to the reservoir 29, and the ink that has flowed into the upper end of the internal flow path 28 from the ink tank via the ink supply flow path flows into the reservoir 29 after flowing through the internal flow path 28. Supplied. The ink supplied to the reservoir 29 is supplied to be distributed to each of the plurality of cavities 31 via the ink supply port 30.

  When a drive signal is input to the piezoelectric element 25 via the cable 27, the piezoelectric element 25 expands and contracts. As a result, the diaphragm 19 is deformed (moved) in a direction toward and away from the cavity. As a result, the volume of the cavity 31 changes, and the pressure of the cavity 31 containing ink changes. Ink is ejected from the nozzle openings 17 due to this pressure fluctuation.

  As described above, the piezoelectric element 25 of the present embodiment varies the pressure of the cavity 31 connected to the nozzle opening 17 based on the input drive signal in order to eject ink from the nozzle opening 17. Then, a desired image is formed on the recording paper 12 by the ink ejected from the nozzle opening 17.

Further, the line head 13 is movable in the vertical direction by a line head moving mechanism 70 (see FIG. 7).
More specifically, the line head 13 is movable in the vertical direction between the printing position and the maintenance position by the line head moving mechanism 70.

  The printing position is a position where recording is performed by ejecting ink from the nozzle openings 17 of the line head 13 to the recording paper 12, and is a position where the line head 13 is relatively moved upward. The maintenance position is a position where maintenance processing of the line head 13 is performed by the maintenance unit 11 described in detail below, and is a position where the line head 13 is relatively moved downward.

  FIG. 5 shows a cross-sectional configuration when the line head shown in FIG. 4 is cut along a plane in the direction of the arrow in FIG. 4 (lower right in the figure). The direction of the arrow in FIG. 4 corresponds to the direction of the arrow in FIG. 5 (lower center in the figure). As shown in FIG. 5, the interior of the reservoir 29 is formed such that the direction along the direction in which the nozzle openings 17 are arranged is long. An internal flow path 28 through which ink is circulated in the reservoir 29 is provided in the central portion of the reservoir 29 in the left-right direction in the figure.

  In the reservoir 29, the ink flows more easily in the left-right central portion in the figure, which is closer to the internal flow path 28, and less likely to flow in the left-right direction end in the figure, which is farther from the internal flow path 28. A distribution of the ease of ink flow is formed. This distribution of the ease of flow is an example, and the distribution of the ease of flow of ink naturally varies depending on the position of the internal flow path 28, the shape of the reservoir 29, the length in the longitudinal direction, and the like. The distribution of the ease of ink flow can be easily grasped by circulating ink from the reservoir 29 to the cavity 31.

  The maintenance unit 11 includes a capping mechanism 40 for preventing the nozzle opening 17 from drying or preventing an increase in ink viscosity in the vicinity of the nozzle opening 17, and an ink discharge unit 41 for discharging the ink accumulated in the capping mechanism 40. A waste ink tank 39 for collecting the ink discharged by the maintenance unit 42 and the ink discharge unit 41 is provided.

FIG. 6 is a diagram illustrating a configuration of the suction pump coupled to the cap member.
The ink discharge unit 41 is connected to the cap member 43 and discharges ink collected in the cap member 43, and a suction pump for sucking ink stored in the cap member 43 into the ink discharge channel. 49 etc.

  Each branch end of a discharge tube 47 made of a flexible material or the like is connected to the discharge channel 43 a, and the other end of the discharge tube 47 is inserted into the waste ink tank 39. The discharge tube 47 has a length sufficient for the cap member 43 to move along the nozzle formation region 21 </ b> B of the line head 13. A waste ink absorbing material 48 made of a porous member is accommodated in the waste ink tank 39, and the ink 2 collected by the waste ink absorbing material 48 is absorbed.

  A tube pump type suction pump 49 is disposed between the cap member 43 and the waste ink tank 39. The suction pump 49 has a cylindrical case 50, and a pump wheel 51 having a circular shape in plan view is rotated around a wheel shaft 52 provided at the axial center of the case 50. Contained as possible. And in this case 50, the intermediate part 47a of the discharge tube 47 is accommodated along the inner peripheral wall 50a of the case 50.

  The pump foil 51 is formed with a pair of arcuate roller guide grooves 53 and 54 that swell outward, with the wheel shaft 52 interposed therebetween. One end of each of the roller guide grooves 53 and 54 is positioned on the outer peripheral side of the pump wheel 51, and the other end is positioned on the inner peripheral side of the pump wheel 51. That is, both the roller guide grooves 53 and 54 gradually extend away from the outer peripheral portion of the pump wheel 51 as they go from one end to the other end.

  A pair of rollers 55 and 56 as pressing means are inserted and supported in both roller guide grooves 53 and 54 through rotation shafts 55a and 56a, respectively. Both the rotating shafts 55a and 56a are slidable in the roller guide grooves 53 and 54, respectively.

  When the pump wheel 51 is rotated in the forward direction (arrow direction), both rollers 55 and 56 move to one end side of both roller guide grooves 53 and 54 (the outer peripheral side of the pump wheel 51), and the discharge tube 47. The intermediate portion 47a is rotated while being sequentially crushed (pressed) from the upstream side to the downstream side. By this rotation, the inside of the discharge tube 47 on the upstream side of the suction pump 49 is decompressed.

FIG. 7 is a block diagram illustrating an electrical configuration of the inkjet printer 100.
The ink jet printer 100 according to this embodiment includes a control device 60 that controls the operation of the entire ink jet printer 100. The control device 60 includes an input device 61 for inputting various information relating to the operation of the ink jet printer 100, a storage device 62 storing various information relating to the operation of the ink jet printer 100, and a measuring device 63 capable of measuring time. It is connected. The control device 60 is connected to the maintenance unit 42 including the recording paper transport mechanism 14, the cap member 43, and the suction pump 49 described above. The ink jet printer 100 also includes a drive signal generator 64 that generates a drive signal to be input to the drive unit 24 including the piezoelectric element 25. The drive signal generator 64 is connected to the control device 60. The drive signal generator 64 receives data indicating the amount of change in the voltage value of the ejection pulse input to the piezoelectric element 25 of the line head 13 and a timing signal that defines the timing for changing the voltage of the ejection pulse. The drive signal generator 64 generates a drive signal including, for example, the ejection pulse DP based on the input data and the timing signal.

  The inkjet printer 100 according to the present embodiment can perform maintenance processing on the line head 13 using the maintenance unit 42. The maintenance unit 42 performs a maintenance process including an operation of discharging ink from the nozzle openings 17 in cooperation with the line head 13 in order to maintain or restore the ejection characteristics of the line head 13.

  The maintenance process includes at least one of a flushing operation for ejecting ink from the nozzle opening 17 to the cap member 43 and an ink suction operation by the cap member 43 of the maintenance unit 42 and the suction pump 49. In the present embodiment, the moisture retention of the nozzle opening 17 by the cap member 43 is also included in the maintenance process as a moisture retention operation.

  The flushing operation by the line head 13 is performed in advance by supplying ink from the nozzle opening 17 to the cap member 43 in a state where the nozzle forming surface 21A is sealed by the cap member 43 before supplying the ink from the nozzle opening 17 to the recording paper. Including the operation of spraying. As a result, during printing or standby, the frequency of use of a specific nozzle opening 17 is reduced, ink with increased viscosity in the vicinity of the nozzle opening 17 is discharged, and the ejection characteristics of the nozzle opening 17 are maintained or recovered.

  In the suction operation, the cap member 43 and the nozzle forming surface 21A are moved while moving the cap member 43 along the nozzle forming region 21B in a state where a part of the nozzle forming region 21B is covered with the cap member 43 in the nozzle forming surface 21A. The operation includes suctioning ink from the nozzle openings 17 by setting the space formed between the nozzle openings 17 to a negative pressure using the suction pump 49. As a result, ink with increased viscosity that could not be discharged by the flushing operation, dust that has entered the nozzle opening 17, bubbles in the line head 13, etc. are discharged together with the ink from the nozzle opening 17, and the ejection characteristics of the nozzle opening 17. Is maintained or recovered.

  When the ink 2 is collected in the cap member 43, the suction pump 49 is driven to discharge the ink 2 before the ink 2 overflows. As described above, since the suction pump 49 is driven by the paper feed motor, it is necessary to stop and perform recording (printing / printing) processing including paper feed / discharge. For this reason, it is required to store as much ink 2 as possible on the cap member 43 to suppress the frequency of the suction process.

Next, an example of the operation of the ink jet printer having the above-described configuration will be described. Here, the operation of the maintenance unit including the suction operation and the moisturizing operation will be mainly described. FIG. 9 is a flowchart showing the operation of the ink jet printer.
When the print data is transmitted from the outside, the control device 60 develops the ejection data corresponding to the dot pattern and transmits it to the line head 13. The line head 13 executes a recording (printing / printing) process, that is, the ejection of the ink droplet D onto the recording paper, based on the received ejection data.

  If it is determined that the operation is to be continued after the recording process, the periodic maintenance process is started when a preset time has elapsed. If it is determined that the operation is not continued after the recording process, the inkjet printer process is terminated. Hereinafter, the case where it is determined that the operation is continued will be described.

  When the periodic maintenance process starts, the control device 60 lowers the line head 13 to the maintenance position, brings the line head 13 and the cap member 43 into contact with each other, and seals the space on the nozzle forming surface 21A.

  Subsequently, the control device 60 drives the suction pump 49 so that the space between the nozzle forming surface 21A and the cap member 43 is in a negative pressure state, whereby ink is discharged from the inside of the line head 13 through the nozzle openings 17. Suction. The ink 2 in the line head 13 is discharged from the nozzle opening 17.

  Thereafter, the control device 60 reversely drives the suction pump 49 to release the negative pressure space formed between the nozzle forming surface 21A and the cap member 43 to the atmosphere. By reversely driving the suction pump 49, air flows between the nozzle forming surface 21 </ b> A and the cap member 43 and is released to the atmosphere. Before the upper end surface of the cap member 43 is separated from the nozzle forming surface 21A, the space between the nozzle forming surface 21A and the cap member 43 is opened to the atmosphere so that the ink interface (meniscus) state of the nozzle opening 17 is maintained. it can.

Then, the control device 60 raises the line head 13 to separate the cap member 43 from the nozzle forming surface 21A.
Thereafter, the control device 60 resumes the recording operation on the recording paper using the line head 13.
On the other hand, when performing the moisturizing operation, the control device 60 performs the above operation while the ink 2 is stored in the cap member 43 by a flushing operation or the like.

  Due to the use of the ink jet printer 100, bubbles are generated in the ink circulation portion in the line head 13. The bubbles are discharged together with the ink from the nozzle opening 17 by a flushing operation, a suction operation, or the like. However, as shown in FIG. 8, some of the bubbles B may remain in a portion of the reservoir 29 where the ink flow rate is low. is there. In the maintenance operation, an operation for discharging the remaining bubbles is also performed. Hereinafter, the bubble discharging operation will be described.

  In the bubble discharging operation, the control device 60 supplies ink to the nozzle openings 17 so that ink convection is formed in a predetermined direction in the reservoir 29. As this “predetermined direction”, for example, in the reservoir 29, for example, when normal ink ejection is performed, a portion where the flow velocity of the ink is slow (for example, the longitudinal end portion of the reservoir 29) to a portion where the flow velocity is high (for example, the longitudinal direction of the reservoir 29). The direction can be the direction toward the center of the direction. In this case, for example, as shown in FIG. 9, the control device 60 controls the ink to be supplied to the nozzle openings 17 located at the end portions in the arrangement direction. With this control, ink convection from the longitudinal end of the reservoir 29 toward the longitudinal center can be formed. Due to this convection, as shown in FIG. 10, the bubbles remaining at the end portion in the longitudinal direction of the reservoir 29 move to the central portion in the longitudinal direction of the reservoir 29.

  After the convection is formed, the control device 60 discharges the ink in the reservoir 29 to the nozzle opening 17 by, for example, the above flushing operation. Since the central portion of the reservoir 29 in the longitudinal direction is a portion where the ink flow velocity is high in the normal ink ejection operation, the bubble that has moved to this position moves to the cavity 31 together with the ink, as shown in FIG. Then, it is discharged to the outside through the nozzle opening 17.

  In this ink ejection operation, ink is selectively ejected from the nozzle opening 17 provided at the position where the ink flows by convection among the plurality of nozzle openings 17, that is, the nozzle opening 17 located in the center in the arrangement direction. You may control so that it is. By this operation, the amount of ink consumed can be suppressed as compared with the case where ink is ejected from all the nozzle openings 17.

  Thus, according to the present embodiment, at the time of maintenance, ink is supplied to the plurality of nozzle openings 17 so that convection of ink is formed in a predetermined direction in the reservoir 29 by the control of the control device 60. Even when the fluid flow is distributed in the reservoir 29, the bubbles can be moved in a predetermined direction by the convection. Further, since the ink in the reservoir 29 is discharged to the nozzle opening side after the formation of convection by the control of the control device 60, the moved bubbles can be easily discharged together with the ink. Thereby, it is possible to prevent bubbles from remaining in the reservoir 29 and to prevent missing dots.

The technical scope of the present invention is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present invention.
In the above-described embodiment, the direction of the ink convection generated when the bubbles are moved (predetermined direction) is a portion in the reservoir 29 where the flow velocity of the ink is low (for example, the longitudinal direction of the reservoir 29). The direction from the one end in the longitudinal direction in the reservoir 29 to the other is not limited to this. Ink convection may be generated in the direction toward the end. In this case, since the bubbles move to the other end portion in the reservoir 29, when discharging ink, the bubbles are easily discharged by intensively discharging ink from the nozzle openings 17 corresponding to the other end portion. Can be discharged.

  In the above embodiment, the control is performed so that the ink is ejected from the nozzle opening 17 when the ink in the reservoir 29 is discharged after the bubble is moved. However, the present invention is not limited to this. For example, the capping mechanism 40 The ink may be controlled to be discharged from the nozzle opening 17 by performing a suction operation using the nozzle. With this control, the bubbles can be discharged together with the ink from the nozzle opening 17 at the position where the bubbles have moved.

  In the above embodiment, the line head 13 is described as an example of the ejection head. However, the present invention is not limited to the line head 13, and the present invention can be applied to other ejection heads provided with a plurality of nozzle openings. Applicable.

  In the above-described embodiment, the fluid ejecting apparatus is embodied as an ink jet recording apparatus. However, the present invention is not limited to this, and liquid other than ink (a liquid in which functional material particles are dispersed in addition to liquid, It can also be embodied in a fluid ejecting apparatus that ejects or ejects a fluid (including a fluid such as a gel). For example, a liquid material injection device for injecting a liquid material in the form of dispersed or dissolved materials such as electrode materials and color materials used in the manufacture of liquid crystal displays, EL (electroluminescence) displays, and surface-emitting displays, and biochip manufacturing It may be a liquid ejecting apparatus for ejecting a bio-organic substance used in the above, or a liquid ejecting apparatus for ejecting a liquid as a sample used as a precision pipette. In addition, transparent resin liquids such as UV curable resin to form liquid injection devices that pinpoint lubricant oil onto precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. May be a liquid ejecting apparatus that ejects a liquid onto the substrate, a liquid ejecting apparatus that ejects an etching solution such as acid or alkali to etch the substrate, or a fluid ejecting apparatus that ejects gel. The present invention can be applied to any one of these injection devices.

1 is a schematic configuration diagram of an inkjet printer according to an embodiment of the present invention. The principal part top view around a line head. The top view which shows the nozzle formation surface of a line head. Sectional drawing of the principal part of a line head. Sectional drawing of the principal part of a line head. The schematic block diagram of a suction pump. FIG. 2 is a block diagram illustrating an electrical configuration of an inkjet printer. Explanatory drawing explaining the maintenance operation | movement in an inkjet printer. FIG. FIG. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Inkjet printer (fluid ejecting apparatus), 17 ... Nozzle opening, 13 ... Line head (ejection head), 21A ... Nozzle formation surface, 25 ... Piezoelectric element, 28 ... Internal flow path, 29 ... Reservoir, 30 ... Ink supply port 31 ... Cavity 43 ... Cap member 49 ... Suction pump 60 ... Control device B ... Bubble

Claims (6)

An ejection head having a plurality of nozzle openings for ejecting fluid and a fluid holding unit connected to the plurality of nozzle openings to hold the fluid;
A fluid ejecting apparatus comprising: a fluid supply unit connected to the fluid holding unit and capable of supplying the fluid independently to a plurality of the nozzle openings;
During maintenance of the ejection head, the fluid is supplied to the plurality of nozzle openings so that convection of the fluid is formed in a predetermined direction in the fluid holding unit, and the fluid in the fluid supply unit is formed after the convection is formed. A fluid ejecting apparatus, further comprising: a controller that discharges the gas toward the nozzle opening side. The fluid ejecting apparatus according to claim 1, wherein the control unit causes the fluid to be supplied to the nozzle opening provided at a position where the fluid flows by the convection among the plurality of nozzle openings. A suction mechanism for sucking the space provided so as to be able to seal a space including the plurality of nozzle openings;
The fluid ejecting apparatus according to claim 1, wherein the controller discharges the fluid to the nozzle opening side by causing the suction mechanism to suck the space. An ejection head having a plurality of nozzle openings for ejecting a fluid and a fluid holding portion connected to each of the plurality of nozzle openings to hold the fluid;
A fluid supply device that is connected to the fluid holding unit and can supply the fluid independently to a plurality of the nozzle openings,
Supplying the fluid to the plurality of nozzle openings so that convection of the fluid is formed in a predetermined direction in the fluid holding portion;
A maintenance method for a fluid ejecting apparatus, wherein the fluid in the fluid supply unit is discharged to the nozzle opening side after the convection is formed. The fluid ejection device maintenance method according to claim 4, wherein the fluid is supplied to the nozzle opening provided at a position where the fluid flows by the convection among the plurality of nozzle openings. The fluid ejecting apparatus further includes a suction mechanism that is provided so as to be able to seal a space including a plurality of the nozzle openings and sucks the space.
The fluid ejection device maintenance method according to claim 4, wherein the fluid is discharged to the nozzle opening side by causing the suction mechanism to suck the space.

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