JP2010194867A - Fluid jetting apparatus and maintenance method for fluid jetting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid jetting apparatus and a maintenance method for a fluid jetting apparatus in which useless consumption of ink can be prevented. <P>SOLUTION: The fluid jetting apparatus PRT includes a fluid jetting head 11 which has a plurality of nozzles 13 to jet the fluid to a medium M, and a pressure generating unit which alternately generates a positive pressure and a negative pressure near the nozzles 13. The pressure generating unit generates the positive pressure to push the fluid into the nozzles 13 while generating the negative pressure to draw the fluid outside keeping the fluid from being jetted from within the nozzles 13. <P>COPYRIGHT: (C)2010,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, an ink jet recording apparatus that ejects ink (fluid) onto a recording medium from a nozzle of a recording head (fluid ejecting head) is known. In such an ink jet recording apparatus, the ejection speed and ejection amount of ink from the nozzles change with the passage of time, and the ejection state (ejection state) of the ink changes. For this reason, in order to maintain the discharge speed and discharge amount of ink within a desired range, the print head is regularly maintained.

  If the ink thickens with time in the recording head, color unevenness or clogging may occur. Therefore, nozzle maintenance is performed by periodically performing a suction operation using a capping device (see, for example, Patent Document 1).

JP 2001-219567 A

  However, normally, in maintenance using a capping device, ink is discharged from all nozzles, so that ink is also sucked from nozzles that are not thickened. Therefore, there has been a problem that ink is wasted.

  SUMMARY An advantage of some aspects of the invention is that it provides a fluid ejecting apparatus and a fluid ejecting apparatus maintenance method capable of preventing wasteful consumption of ink.

  In order to solve the above problems, a fluid ejecting apparatus of the present invention includes a fluid ejecting head having a plurality of nozzles that eject a fluid onto a medium, and a pressure generating unit that alternately generates positive pressure and negative pressure in the vicinity of the nozzles. The pressure generation unit generates the positive pressure so as to push the fluid into the nozzle while generating the negative pressure so as to draw the fluid outside without ejecting the fluid from within the nozzle. It is characterized by making it.

  According to the fluid ejecting apparatus of the present invention, the fluid can be taken in and out of the nozzle by the pressure generating unit. Therefore, the fluid can be stirred inside the fluid ejecting head, and the occurrence of color unevenness and clogging can be prevented without performing the conventional suction operation. Further, since it is not necessary to discharge the fluid from the nozzle as in the suction operation, it is possible to suppress the consumption of the fluid and obtain a stable fluid ejection characteristic.

In the fluid ejecting apparatus, the fluid ejecting head includes a pressure chamber that communicates with the nozzle and a piezoelectric element that changes a volume of the pressure chamber, and the pressure generating unit includes the piezoelectric element that includes the piezoelectric element. It is preferable that the negative pressure is generated in synchronization with an operation of increasing the volume of the pressure chamber, and the positive pressure is generated in synchronization with an operation of decreasing the volume of the pressure chamber.
According to this configuration, the fluid is drawn out from the nozzle when the volume of the pressure chamber increases, and the fluid is pushed into the nozzle when the volume of the pressure chamber decreases. The amount increases and the fluid can be well stirred.

In the fluid ejecting apparatus, it is preferable that the pressure generating unit generates the positive pressure and the negative pressure with a strength that does not destroy the meniscus of the fluid in the nozzle.
According to this configuration, since the meniscus in the nozzle is prevented from being destroyed, the flushing operation for adjusting the meniscus can be omitted after the maintenance by the pressure generating unit is completed.

In the fluid ejecting apparatus, the fluid ejecting apparatus includes a detecting device that detects a state of ejection of the fluid in each of the nozzles of the fluid ejecting head, and the pressure generating unit is configured to It is preferable that the positive pressure and the negative pressure are generated in the vicinity of a defective nozzle that is detected as having a fluid ejection failure.
According to this configuration, the time required for maintenance can be shortened by selectively stirring the fluid in the defective nozzle.

Further, in the fluid ejecting apparatus, the pressure generating unit includes a main body portion having a recess having a size corresponding to a part of the nozzles, and a pressurizing / depressurizing device capable of pressurizing or depressurizing the inside of the recess. It is preferable to provide.
According to this configuration, the fluid can be stirred for each of the nozzles. Therefore, for example, when the main body is in a non-contact state with respect to the fluid ejecting head, the driving force of the pressure increasing / decreasing device can be suppressed, and the device can be downsized.

  The maintenance method for a fluid ejecting apparatus according to the present invention is a maintenance method for a fluid ejecting apparatus including a fluid ejecting head having a plurality of nozzles for ejecting a fluid to a medium, and generating a negative pressure near the nozzle to cause the fluid to flow. A negative pressure generating step of drawing outside without ejecting from the nozzle, and a positive pressure generating step of generating a positive pressure in the vicinity of the nozzle and pushing the fluid into the nozzle, the negative pressure generating step and the positive pressure generating step The pressure generation process is alternately repeated.

  According to the maintenance method of the fluid ejecting apparatus of the present invention, the fluid is taken in and out of the nozzle by the negative pressure generating step and the positive pressure generating step. Therefore, the fluid can be stirred inside the fluid ejecting head, and the occurrence of color unevenness and clogging can be prevented without performing the conventional suction operation. Further, since it is not necessary to discharge the fluid from the nozzle as in the suction operation, it is possible to suppress the consumption of the fluid and obtain a stable fluid ejection characteristic.

In the maintenance method of the fluid ejecting apparatus, in the negative pressure generating step, the piezoelectric element of the fluid ejecting head is placed in the vicinity of the nozzle in synchronization with an operation of increasing the volume of the pressure chamber communicating with the nozzle. Preferably, the negative pressure is generated, and in the positive pressure generating step, the positive pressure is generated in the vicinity of the nozzle in synchronism with an operation in which the piezoelectric element reduces the volume of the pressure chamber.
According to this configuration, the fluid is drawn out from the nozzle when the volume of the pressure chamber increases, and the fluid is pushed into the nozzle when the volume of the pressure chamber decreases. The amount increases and the fluid can be well stirred.

In the maintenance method of the fluid ejecting apparatus, it is preferable that the positive pressure and the negative pressure are generated with a strength that does not destroy the meniscus in the nozzle in the negative pressure generation step and the positive pressure generation step. .
According to this configuration, since the meniscus in the nozzle is prevented from being destroyed, the fluid can be ejected from the nozzle satisfactorily after the maintenance is completed.

In the maintenance method for the fluid ejecting apparatus, the fluid ejecting head includes a detecting step for detecting the fluid ejecting state in each of the nozzles, and the fluid ejecting failure is caused by the detecting step. It is preferable that the negative pressure generation step and the positive pressure generation step are alternately repeated for the detected defective nozzle.
According to this configuration, since the fluid in the defective nozzle can be selectively stirred, the time required for maintenance can be shortened.

1 is a schematic diagram showing a configuration of a printer apparatus according to an embodiment of the present invention. FIG. 3 is a plan view of a main part around an ejection head. The top view which shows the nozzle opening formation surface of an ejection head. The figure which shows the cross-sectional structure of an ejection head. The schematic diagram which shows schematic structure of a maintenance mechanism. The figure which shows typically the planar structure of the main-body part of a negative pressure generation unit. FIG. 3 is a schematic diagram illustrating a configuration of an ink droplet sensor. The figure which shows the detection principle of an ink drop sensor. The graph which shows the voltage waveform detected by an ink drop sensor. FIG. 2 is a block diagram illustrating a configuration of a printer apparatus. FIG. 3 is a diagram illustrating an operation state of a printer apparatus. FIG. 3 is a diagram illustrating an operation state of a printer apparatus. FIG. 9 is a diagram illustrating a configuration according to a modified example of the printer apparatus.

  Hereinafter, an embodiment of a fluid ejecting apparatus according to the invention will be described with reference to the drawings. In order to make each member of the fluid ejecting apparatus have a recognizable size, each drawing used in the following description shows each member in a state where the scale is appropriately changed. In the present embodiment, an ink jet printer apparatus will be described as an example of the fluid ejecting apparatus.

  FIG. 1 is a schematic configuration diagram of an ink jet printer (hereinafter referred to as a printer apparatus PRT) according to the present embodiment. FIG. 2 is a plan view of a main part around the ejection head. FIG. 3 is a plan view showing a nozzle opening forming surface of the ejection head.

  In FIG. 1, an XYZ orthogonal coordinate system is set, and the positional relationship of each member may be described with reference to the XYZ orthogonal coordinate system. In this case, the left-right direction in the figure is the X direction, the depth direction of the paper surface in the figure is the Y direction, and the direction orthogonal to each of the X direction and the Y direction (that is, the vertical direction in the figure) is the Z direction.

  As shown in these drawings, the printer device PRT is a device that records images, characters, and the like on a recording medium M. As the recording medium M, for example, paper or plastic is used. The printer device PRT has an ink ejection mechanism IJ, a transport mechanism CR, a maintenance mechanism MN, and a control device CONT.

  The ink ejecting mechanism IJ is a part that ejects ink droplets (fluid) onto the recording medium M. The ink ejection mechanism IJ includes an ejection head (fluid ejection head) 11 and an ink supply unit 12. The ink used in the present embodiment uses a liquid in which dyes and pigments and a solvent for dissolving or dispersing them are basic components and various additives are added as necessary.

  The ejection head 11 is a head that can eject ink droplets of a plurality of colors onto the recording medium M. For example, as shown in FIG. 2, the ejection head 11 is a line type having an ejection area 15 over a length (maximum recording paper width W) exceeding at least one side of the maximum size recording medium M targeted by the printer apparatus PRT. It is an ejection head. The ejection head 11 is provided so as to be movable in the Z direction, for example. The ejection head 11 has a nozzle 13 and a common ink chamber 14.

  The common ink chamber 14 holds ink corresponding to, for example, four colors (yellow: Y, magenta: M, cyan: C, black: K) (common ink chambers 14Y, 14M, 14C, 14K). The ejection area 15 is provided corresponding to the common ink chamber 14 of each color (ejection areas 15Y, 15M, 15C, 15K).

  A plurality of nozzles 13 are provided in each of the ejection regions 15Y, 15M, 15C, and 15K of the ejection head 11, and are, for example, openings that eject the four color ink droplets. For example, as shown in FIG. 3, four rows of nozzles 13 are arranged in the Y direction (nozzle row L). One or a plurality of nozzle rows L are provided for the ejection regions 15Y, 15M, 15C, and 15K of the respective colors. The number of nozzles 13 and the number of nozzle rows L are set as appropriate. A surface of the ejection head 11 on which the nozzles 13 are provided is an ejection surface 11A. The ejection surface 11 </ b> A is provided on the −Z side of the ejection head 11. The ejection head 11 ejects ink droplets toward the −Z side.

FIG. 4 is a cross-sectional view showing the configuration of the ejection head 11.
As shown in the figure, the ejection head 11 includes a head main body 18 and a flow path forming unit 22 connected to the head main body 18. The flow path forming unit 22 includes a vibration plate 19, a flow path substrate 20, and a nozzle substrate 21.

  The head body 18 is a box-shaped member made of synthetic resin. The head body 18 is formed with a storage chamber 23 for storing the drive unit 24 and an internal flow path 28 for guiding ink supplied from the outside to the flow path forming unit 22.

  The drive unit 24 disposed in the accommodation chamber 23 includes a plurality of piezoelectric elements 25, a fixing member 26 that supports the upper ends of the plurality of piezoelectric elements 25, and a flexible cable 27 that supplies a drive signal to the piezoelectric elements 25. I have. The piezoelectric element 25 is provided corresponding to each of the plurality of nozzles 13.

  The internal flow path 28 is formed so as to penetrate the head body 18 in the vertical direction in FIG. The upper end of the internal channel 28 is connected to the ink supply unit 12 and the pressure mechanism 38 in the drawing. The internal flow path 28 is an ink flow path for allowing the ink supplied from the ink supply unit 12 to flow to the flow path forming unit 22 through the opening end on the lower end side in the figure.

  The flow path forming unit 22 has a configuration in which the diaphragm 19, the flow path substrate 20, and the nozzle substrate 21 are stacked and joined and integrated with an adhesive or the like. The flow path forming unit 22 includes a common ink chamber 14 connected to the internal flow path 28 of the head body 18, an ink supply port 30 connected to the common ink chamber 14, and a pressure chamber connected to the ink supply port 30. 31. The pressure chamber 31 is provided corresponding to each nozzle 13. Each pressure chamber 31 is connected to the nozzle 13 at the end opposite to the common ink chamber 14.

  The diaphragm 19 has a configuration in which an elastic film is laminated on a metal support plate such as stainless steel. An island portion 32 is formed in a portion of the diaphragm 19 corresponding to the pressure chamber 31. The island portion 32 is joined to the lower end of the piezoelectric element 25 by removing the support plate in an annular shape by etching or the like, for example.

  The island part 32 functions as a diaphragm part. In the diaphragm 19, the elastic film portion around the island portion 32 is elastically deformed according to the driving of the piezoelectric element 25 on the pressure chamber 31, and the island portion 32 moves up and down. Between the vibration plate 19 and the vicinity of the lower end of the internal flow path 28, a portion in which a part of the support plate is removed to make only an elastic film is provided, and this portion reduces the pressure fluctuation in the common ink chamber 14. It becomes the compliance part 33 to absorb.

  The flow path substrate 20 has a recess for forming an ink circulation chamber such as a common ink chamber 14 that connects the lower end of the internal flow path 28 and the nozzle 13, an ink supply port 30, and a pressure chamber 31. These recesses are formed by anisotropically etching a silicon single crystal substrate that is a base material of the flow path substrate 20.

  The nozzle substrate 21 has a plurality of nozzles 13 formed at a predetermined interval (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 outer surface of the nozzle substrate 21 is the ejection surface 11A.

  The ejection head 11 configured in this manner is configured such that the piezoelectric element 25 expands and contracts when a drive signal is input to the piezoelectric element 25 via the cable 27. The expansion and contraction of the piezoelectric element 25 is transmitted as deformation of the diaphragm 19 (deformation in a direction approaching and leaving the cavity). Due to the deformation of the vibration plate 19, the volume of the pressure chamber 31 changes, and the pressure of the pressure chamber 31 containing ink fluctuates. Ink is ejected from the nozzle 13 due to the fluctuation of the pressure.

  Returning to FIG. 1, the ink supply unit 12 is disposed on one side of the ink ejection mechanism IJ, and is connected to the common ink chambers 14 </ b> Y, 14 </ b> M, 14 </ b> C, and 14 </ b> K of the ejection head 11. The ink supply unit 12 includes ink tanks 12Y, 12M, 12C, and 12K that store the four colors of ink. The ink supply unit 12 has an ink supply mechanism (not shown), and supplies ink to the ejection head 11 using the ink supply mechanism.

  The transport mechanism CR includes a paper feed roller 35, a discharge roller 36, and the like. The paper feed roller 35 and the discharge roller 36 are rotationally driven by a motor mechanism (not shown). The transport mechanism CR transports the recording medium M along the transport path MR in conjunction with the ink droplet ejecting operation by the ink ejecting mechanism IJ.

FIG. 5 is a diagram schematically illustrating a schematic configuration of the maintenance mechanism MN.
The maintenance mechanism MN includes a flushing unit 40 and a pressure generation unit 50. The flushing unit 40 includes an ink receiving member 41 and an ink absorber 42 as shown in FIG. The ink receiving member 41 is a tray-like member having an open upper surface, and the ink absorber 42 is accommodated inside. The flushing unit 40 is used during a flushing operation for maintaining the ejection characteristics of the nozzle 13.

  The ink absorber 42 is formed of a sponge-like member capable of holding (absorbing) ink or a porous member. In the present embodiment, the ink absorber 42 is formed of a nonwoven fabric such as felt.

  An electrode member 45 is disposed above the ink absorber 42 provided inside the ink receiving member 41. The electrode member 45 is formed of a metal mesh member such as stainless steel. The ink droplets that have landed on the electrode member 45 pass through the gaps in the grid-like electrode member 45 and are held (absorbed) by the ink absorber 42 disposed on the lower side. Note that the electrode member 45 may not be a mesh member as long as ink droplets can pass through.

  The pressure generating unit 50 includes a main body 51 in which a recess 51 a is formed, and a pump (pressurization / decompression device) 53 connected to the recess 51 a via a tube 52. As the pump 53, a pump that can pressurize or depressurize the recess 51a is used.

FIG. 6 is a diagram schematically showing a planar configuration of the main body 51 of the pressure generating unit 50.
As shown in FIG. 6, the recess 51 a formed in the main body 51 is formed in a size corresponding to a part of the nozzles 13 in the ejection head 11 in a plan view. Specifically, in the present embodiment, the concave portion 51a having a size including, for example, three nozzles 13 arranged in a straight line is formed.
The pressure generating unit 50 is driven in a non-contact state with the ejection surface 11A of the ejection head 11 as will be described in detail later. In the present embodiment, since the concave portion 51a is formed in a size including the three nozzles 13 as described above, the pump 53 for generating positive pressure or negative pressure in the vicinity of the nozzle 13 facing the concave portion 51a. The driving force is reduced. Therefore, a small pump 53 can be used.

Moreover, as shown in FIG. 5, the inside of the tube 52 and the recessed part 51a are connected via the connection part 51b, and the other end side of the tube 52 is an air | atmosphere release state. Thereby, the pump 53 can generate a positive pressure and a negative pressure in the recess 51a.
Further, the pressure generating unit 50 includes a drive mechanism (not shown), and the main body 51 can be moved to a predetermined position on the ejection surface 11A of the ejection head 11 by this drive mechanism.

FIG. 7 is a diagram illustrating a schematic configuration of an ink droplet sensor mounted on the printer apparatus.
The printer device PRT of the present embodiment includes an ink droplet sensor (detection unit) 60 that can detect the ink ejection status of each nozzle 13. As shown in FIG. 7, the ink droplet sensor 60 includes a voltage application device 71 that applies a voltage to the nozzle substrate 21 of the ejection head 11, the electrode member 45 that receives ink ejected from the ejection head 11, and the electrode member 45. A voltage detector 73 that detects the voltage and a processing device 74 that processes the detection result of the voltage detector 73 are included.

  The ink droplet sensor 60 applies an electric field between the ejection surface 11 </ b> A of the ejection head 11 and the electrode member 45, and changes the voltage value over time based on electrostatic induction when the ink moves from the nozzle 13 to the electrode member 45. The detected waveform is output to the processing device 74. Based on the detection waveform output from the ink droplet sensor 60, the processing device 74 can acquire information related to the ink weight (that is, the ink ejection status of each nozzle 13). Information on the weight is transmitted to the control device CONT, for example.

  Next, the principle of the ink droplet sensor 60, that is, the principle that an induced voltage is generated by electrostatic induction will be described with reference to the drawings. FIG. 8 is a schematic diagram for explaining the principle that an induced voltage is generated by electrostatic induction. In the drawing, the upper side of the arrow indicates a state immediately after the ink droplet is ejected, and the lower side of the arrow indicates a state where the ink LQ has landed on the electrode member 45.

  FIG. 8 is a diagram illustrating an example of a waveform of a detection signal (for one drop of ink) output from the ink drop sensor 60. In a state where a voltage is applied between the nozzle substrate 21 (negative electrode side) and the electrode member 45 (positive electrode side), the piezoelectric element 25 is driven using an ejection pulse, and ink LQ is ejected from any one nozzle 13. The waveform when it is made to show is shown.

  When the ink LQ is ejected, since the nozzle substrate 21 is a negative electrode, a part of the negative charge of the nozzle substrate 21 moves to the ink LQ, and the ejected ink LQ is negatively charged. As the negatively charged ink LQ approaches the electrode member 45, the positive charge increases on the surface of the electrode member 45 due to electrostatic induction. The voltage between the nozzle substrate 21 and the electrode member 45 is higher than the initial voltage value in a state where the ink LQ is not ejected due to the induced voltage generated by electrostatic induction.

  When the ink LQ lands on the electrode member 45, the positive charge of the electrode member 45 is neutralized by the negative charge of the ink LQ. For this reason, the voltage between the nozzle substrate 21 and the electrode member 45 is lower than the initial voltage value. Thereafter, the voltage between the nozzle substrate 21 and the electrode member 45 returns to the initial voltage value.

  Therefore, as shown in FIG. 9, the detected waveform output from the ink droplet sensor 60 is a waveform that once rises, then falls to below the initial voltage value, and then returns to the original voltage value. In this way, the ink droplet sensor 60 detects a voltage change when the ink LQ is ejected from each nozzle 13.

FIG. 10 is a block diagram showing an electrical configuration of the printer apparatus PRT.
The printer device PRT in the present embodiment includes a control device CONT that controls the overall operation. Connected to the control device CONT are an input device 69 for inputting various information relating to the operation of the printer device PRT, and a storage device 80 storing various information relating to the operation of the printer device PRT.

  Each part of the printer device PRT, such as the ink ejection mechanism IJ, the transport mechanism CR, the maintenance mechanism MN, and the ink droplet sensor 60, is connected to the control device CONT. The printer apparatus PRT includes a drive signal generator 82 that generates a drive signal to be input to a drive unit including the piezoelectric element 25. The drive signal generator 82 is connected to the control device CONT.

  The drive signal generator 82 receives data indicating the amount of change in the voltage value of the ejection pulse input to the piezoelectric element 25 of the ejection head 11 and a timing signal that defines the timing for changing the voltage of the ejection pulse. The drive signal generator 62 generates a drive signal such as an ejection pulse based on the input data and timing signal.

Next, the operation of the printer apparatus PRT configured as described above will be described. In the following description, a maintenance method that is a feature of the printer apparatus PRT will be described.
First, the ink receiving member 41 is positioned below the ejection head 11 by an elevating mechanism (not shown), and the ejection surface 11A of the ejection head 11 and the electrode member 45 provided inside the ink receiving member 41 are in a non-contact state. Make them face each other. Thereby, the ink droplet sensor 60 is set in a standby state.

  Then, a voltage is applied between the ejection surface 11 </ b> A of the ejection head 11 and the electrode member 45 by the voltage application device 71. As a result, the ink droplet sensor 60 is turned on. In a state where the ink droplet sensor 60 is driven as described above, the piezoelectric element 25 is driven using an ejection pulse, and ink droplets are sequentially ejected from each nozzle 13. The ink droplet sensor 60 has a nozzle 13 jetting state, that is, a nozzle 13 in which ink thickening occurs or a nozzle that is clogged due to a voltage change based on electrostatic induction when the ink droplet lands on the electrode member 45. 13 detections can be performed. Then, the ink droplet sensor 60 transmits the detection result described above to the control device CONT by the processing device 74. Thereby, the control device CONT can grasp which of all the nozzles 13 of the ejection head 11 is thickened or clogged. Hereinafter, the nozzle 13 in which thickening or clogging has occurred is referred to as a defective nozzle.

  Subsequently, the control device CONT uses a drive mechanism (not shown) as shown in FIG. 11 to move the main body 51 of the pressure generating unit 50 below the defective nozzle. At this time, the three nozzles 13 are located in the concave portion 51a of the main body 51 in a plan view (see FIG. 6). Note that at least one of the three nozzles may be a defective nozzle (discharge failure nozzle) 13a. The main body 51 is disposed to face the nozzle substrate 21 with a minute gap d therebetween, and is in a non-contact state.

  Then, the control device CONT drives the pump 53. Thereby, the pressure generating unit 50 generates a negative pressure in the vicinity of the defective nozzle 13a by pressurizing the recess 51a, and a negative pressure in the vicinity of the defective nozzle 13a by reducing the pressure in the recess 51a. The negative pressure generating step for generating the above is alternately repeated for the defective nozzle 13a.

  Here, since the gap d between the main body 51 and the nozzle substrate 21 is very small, a negative pressure or a positive pressure can be generated in the vicinity of the defective nozzle 13 a facing the recess 51 a by the pump 53. The control device CONT drives the pump 53 so as to generate a positive pressure or a negative pressure that does not destroy the ink meniscus in the defective nozzle 13a.

  Here, although the main body 51 has a minute gap d between the nozzle substrate 21 (the ejection surface 11A), the recess 51a has a size corresponding to one nozzle 13, so that the defective nozzle 13a The driving force of the pump 53 when generating negative pressure in the vicinity can be suppressed.

  Further, in the negative pressure generating step, the control device CONT drives the pump 53 in synchronization with an operation in which the piezoelectric element 25 of the ejection head 11 increases the volume of the pressure chamber 31, and generates a negative pressure near the defective nozzle 13a. I try to let them. As a result, when the capacity of the pressure chamber 31 increases, ink is drawn out from the defective nozzle 13a. That is, as shown in FIG. 12A, the ink LQ is sent from the common ink chamber 14 through the ink supply port 30 into the pressure chamber 31 having an enlarged volume and is not ejected from the defective nozzle 13a. It will be in the state.

  Further, in the positive pressure generation process, the control device CONT drives the pump 53 in synchronization with the operation of the piezoelectric element 25 of the ejection head 11 decreasing the volume of the pressure chamber 31, and generates a positive pressure near the defective nozzle 13a. I try to let them. As a result, when the volume of the pressure chamber 31 decreases, ink is pushed into the defective nozzle 13a. That is, as shown in FIG. 12B, the ink LQ is drawn into the defective nozzle 13 a and is sent to the common ink chamber 14 side from the pressure chamber 31 whose volume is reduced through the ink supply port 30.

  In the present embodiment, since the negative pressure generation step and the positive pressure generation step are repeated, the ink LQ is formed in the ink supply path including the defective nozzle 13a, the pressure chamber 31, the ink supply port 30, and the common ink chamber 14. Can be stirred. Therefore, thickening of the ink LQ can be prevented, and as a result, occurrence of color unevenness and clogging can be prevented. Further, unlike the conventional suction operation by the capping device, ink is not discharged from the defective nozzle 13a, so that the ink consumption can be suppressed. Further, since the ink is not discharged from the defective nozzle 13a, it is possible to prevent the ink discharged from the nozzle 13 from adhering to the ejection surface 11A of the ejection head 11.

  In addition, when the nozzle 13 arrange | positioned in the recessed part 51a contains the normal nozzle in which the discharge defect does not arise, the above-mentioned ink stirring is performed also to this normal nozzle. Even in this case, as described above, the ink meniscus is prevented from being destroyed in the positive pressure and negative pressure generation process, so that the normal nozzle is not adversely affected.

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 case where the concave portion 51a of the main body portion 51 is a size including a plurality (three) of the ejection heads 11 in a plan view is described, but the shape of the concave portion is not limited thereto. For example, as shown in FIG. 13A, the main body 151 is formed with a recess 151 a having a size including all the nozzles 13 constituting one nozzle row L of the ejection head 11 in a plan view. Can be used. According to this configuration, although the capacity of the pump 53 is somewhat increased, it is possible to perform maintenance on defective nozzles in the nozzle row, that is, the nozzles 13 that discharge the same color ink. Further, since ink is not discharged from the nozzle 13 during maintenance, the occurrence of a problem such as ink mixing in the nozzle 13 is prevented.

  Alternatively, as shown in FIG. 13B, a main body 251 having a recess 251 a having a size including one nozzle 13 of the ejection head 11 in a plan view can be used. According to this configuration, it is only necessary to generate a positive pressure or a negative pressure in the vicinity of one defective nozzle 13a, so that the capacity of the pump 53 can be suppressed, and a smaller one can be used. The printer device PRT itself provided with this can be miniaturized.

In the above embodiment, the printer apparatus PRT having the line type ejection head has been described. However, the present invention can also be applied to a printer apparatus having a serial type ejection head.
In the above embodiment, the printer apparatus PRT having only the pressure generating unit 50 is described. However, a conventional cap apparatus may be mounted together with the pressure generating unit 50. By properly using the pressure generating unit 50 and the cap device according to the application, it is possible to provide a highly reliable printer device that minimizes ink waste during maintenance and has stable ink ejection characteristics.

  In the above embodiment, an ink jet printer and an ink cartridge are employed. However, a liquid ejecting apparatus that ejects or discharges liquid other than ink and a liquid container containing the liquid are employed. Also good. The present invention can be used for various liquid ejecting apparatuses including a liquid ejecting head that ejects a minute amount of liquid droplets. In addition, a droplet means the state of the liquid discharged from the said liquid ejecting apparatus, and shall also include what pulls a tail in granular shape, tear shape, and thread shape. The liquid here may be a material that can be ejected by the liquid ejecting apparatus. For example, it may be in the state when the substance is in a liquid phase, and may be in a liquid state with high or low viscosity, sol, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals (metal melts) ) And a liquid as one state of the substance, as well as particles in which functional material particles made of solid materials such as pigments and metal particles are dissolved, dispersed or mixed in a solvent. In addition, typical examples of the liquid include ink and liquid crystal as described in the above embodiments. Here, the ink includes general water-based inks and oil-based inks, and various liquid compositions such as gel inks and hot-melt inks. As a specific example of the liquid ejecting apparatus, for example, a liquid containing a material such as an electrode material or a coloring material used for manufacturing a liquid crystal display, an EL (electroluminescence) display, a surface emitting display, a color filter, or the like in a dispersed or dissolved state. It may be a liquid ejecting apparatus for ejecting, a liquid ejecting apparatus for ejecting a bio-organic material used for biochip manufacturing, a liquid ejecting apparatus for ejecting a liquid as a sample used as a precision pipette, a textile printing apparatus, a microdispenser, or the like. 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. A liquid ejecting apparatus that ejects a liquid onto the substrate or a liquid ejecting apparatus that ejects an etching solution such as an acid or an alkali to etch the substrate may be employed. The present invention can be applied to any one of these ejecting apparatuses and liquid containers.

PRT: printer device (fluid ejecting device), M: recording medium (medium), CONT ... control device (control unit), 11 ... ejecting head (fluid ejecting head), 13 ... nozzle, 13a ... defective nozzle, 25 ... piezoelectric element , 31 ... Pressure chamber, 50 ... Negative pressure generating unit, 51 ... Body part, 51a ... Recess, 60 ... Ink drop sensor (detection part), 151 ... Body part, 151a ... Recess, 251 ... Body part, 251a ... Recess

Claims (9)

A fluid ejecting head having a plurality of nozzles for ejecting fluid onto a medium;
A pressure generating unit that alternately generates positive pressure and negative pressure in the vicinity of the nozzle, and
The pressure generating unit generates the positive pressure so as to push the fluid into the nozzle while generating the negative pressure so as to draw the fluid outside without ejecting the fluid from the nozzle. Fluid ejecting apparatus. The fluid ejecting head includes a pressure chamber that communicates with the nozzle, and a piezoelectric element that changes a volume of the pressure chamber,
The pressure generating unit is configured to generate the negative pressure in synchronization with an operation in which the piezoelectric element increases the volume of the pressure chamber, and to synchronize with the operation in which the piezoelectric element decreases a volume of the pressure chamber. The fluid ejecting apparatus according to claim 1, wherein pressure is generated.   3. The fluid ejecting apparatus according to claim 1, wherein the pressure generating unit generates the positive pressure and the negative pressure with a strength that does not destroy a meniscus of the fluid in the nozzle. A detection device that detects a state of ejection of the fluid in each of the nozzles of the fluid ejection head;
The pressure generating unit generates the positive pressure and the negative pressure in the vicinity of a defective nozzle that is detected by the detection device as having failed to eject the fluid among the plurality of nozzles. The fluid ejection device according to claim 1.   2. The pressure generating unit includes a main body having a recess having a size corresponding to a part of the nozzles, and a pressure increasing / decreasing device capable of pressurizing or depressurizing the recess. The fluid ejecting apparatus according to claim 1. In a maintenance method of a fluid ejecting apparatus including a fluid ejecting head having a plurality of nozzles that eject a fluid to a medium,
A negative pressure generating step of generating a negative pressure in the vicinity of the nozzle and drawing the fluid to the outside without ejecting the fluid from the nozzle; and a positive pressure of generating a positive pressure in the vicinity of the nozzle and pushing the fluid into the nozzle A pressure generating process,
A maintenance method for a fluid ejecting apparatus, wherein the negative pressure generation step and the positive pressure generation step are alternately repeated. In the negative pressure generating step, the negative pressure is generated in the vicinity of the nozzle in synchronization with an operation in which the piezoelectric element of the fluid ejecting head increases the volume of the pressure chamber communicating with the nozzle,
The fluid ejecting apparatus according to claim 6, wherein, in the positive pressure generating step, the piezoelectric element generates the positive pressure in the vicinity of the nozzle in synchronization with an operation of decreasing the volume of the pressure chamber. Maintenance method.   8. The fluid ejection according to claim 6, wherein, in the negative pressure generation step and the positive pressure generation step, the positive pressure and the negative pressure are generated with a strength that does not destroy a meniscus in the nozzle. How to maintain the equipment. A detection step of detecting a state of ejection of the fluid in each of the nozzles of the fluid ejection head;
9. The negative pressure generation step and the positive pressure generation step are alternately repeated with respect to a defective nozzle that is detected as having failed in the fluid ejection in the detection step. The maintenance method of the fluid ejecting apparatus according to one item.

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