JP2009078514A - Fluid suction method, fluid suction apparatus, and printing inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid suction method and a fluid suction apparatus capable of effectively discharging residual air bubbles in a fluid jet head to prevent the development of printing defects in the fluid jet head and to improve the accuracy of printing inspection including the fluid suction method. <P>SOLUTION: Negative pressure-applying operation includes: a plurality of first negative pressure-applying steps of setting the pressure in a sealed space formed by a nozzle forming surface 33A and a cap member 8 at a predetermined maximum pressure to suck the fluid in a nozzle opening 32; a second negative pressure-applying step in which the maximum pressure is lower than that in the first negative pressure-applying step and pressure changes per unit time at the time of rising and falling are steeper than those in the first negative pressure-applying step; and a third negative pressure-applying step of setting the pressure in the sealed space at the maximum pressure equal to that in the first negative pressure-applying step to suck the fluid in the nozzle opening 32. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fluid suction method, a fluid suction device, and a print inspection method.

  As a fluid ejecting apparatus, an ink jet recording apparatus that ejects ink onto a recording medium from a nozzle formed in a fluid ejecting head (ejection head) is known. In the manufacturing process of such an ink jet recording apparatus, in order to confirm the state of fluid ejection from the nozzle opening, an ejection inspection (printing inspection) is performed with the fluid ejection head alone. In this ejection test, fluid is ejected from the fluid ejection head, the ejection state of the fluid such as whether or not the fluid is normally ejected from the nozzle opening is confirmed, and the ejection characteristics of each fluid ejection head are adjusted. .

A basic configuration as an ink jet recording apparatus is described in Patent Document 1, for example.
JP-A-10-329341

  However, when the above inspection is performed, many bubbles are mixed in the fluid because the fluid ejecting head in an initial state in which no fluid is contained is filled with the fluid. Due to the mixing of bubbles, dot omission due to clogging of the nozzle opening or the like occurs, and there is a problem in that the ejection inspection accuracy decreases. In addition, when many bubbles are mixed, the filling operation is performed again, but it is difficult to fill the bubbles so that no bubbles are mixed at all.

  Moreover, as shown in Patent Document 1, the flow path communicating with each nozzle opening of the fluid ejecting head is configured by a pressure chamber, a reservoir, and the like, and thus has a complicated structure. For this reason, it is difficult to discharge bubbles caught in a step in the flow path.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a fluid suction method and a fluid suction device that can effectively discharge residual bubbles in a fluid ejection head. An object of the present invention is to improve the printing inspection accuracy by preventing the occurrence of ejection failure in the head.

  In order to achieve the above object, the present invention provides a fluid suction method for sucking fluid from a plurality of nozzle openings of a fluid ejecting head, the nozzle surface of the fluid ejecting head, and a cap member covering the nozzle surface. The first negative pressure applying step of sucking the fluid in the nozzle opening by setting the pressure in the space formed by the predetermined maximum pressure, and the maximum pressure is lower than the first negative pressure applying step, and rising and falling The pressure change per unit time is steeper than the first negative pressure application step, the second negative pressure application step, and the pressure in the space is set to the maximum pressure equal to that in the first negative pressure application step. And a third negative pressure applying step of sucking the fluid.

  According to the present invention, in the first negative pressure applying step, some bubbles (micro bubbles) in the fluid ejecting head are discharged, and in the second negative pressure applying step, the bubbles remaining in the fluid ejecting head are removed. It moves and integrates with other bubbles, and in the third negative pressure application step, the bubbles that are integrated and enlarged in the second negative pressure application step are sucked.

  As described above, the air bubbles mixed in the fluid ejecting head can be reliably sucked by the intermittent suction operation by the first to third negative pressure applying steps. When sucking bubbles, bubbles that are somewhat larger than microbubbles are easier to escape. In addition, since there is a tendency that the change (flow / stop) in the flow of the fluid is likely to be removed, the negative pressure application operation is divided into first to third negative pressure application steps and intermittently sucked. Furthermore, between the first negative pressure application step and the third negative pressure application step, the maximum pressure is lower than that of the first negative pressure application step, and the pressure change per unit time at the rise and fall is the first Since the second negative pressure application step, which is steeper than the negative pressure application step, is provided, the second negative pressure application step facilitates the concentration growth of microbubbles and sucks the fluid, thereby mixing in the fluid ejecting head. Air bubbles can be reliably removed by suction.

  As a result, it is possible to prevent a decrease in ejection inspection accuracy due to missing dots of the fluid ejecting head due to mixing of bubbles in the fluid. Therefore, the ejection characteristics of each fluid ejecting head can be confirmed efficiently, and a fluid ejecting head having a satisfactory ejecting function can be manufactured.

  In addition, the retry rate (refilling rate to the fluid ejecting head) can be reduced, and the processing time can be shortened. As a result, productivity (inspection efficiency) is improved.

Moreover, it is preferable that a plurality of second negative pressure application steps are provided between the first negative pressure application step and the third negative pressure application step.
According to the present invention, by providing a plurality of second negative pressure applying steps that are temporally adjacent between the first negative pressure applying step and the third negative pressure applying step, bubbles in the fluid ejecting head are effectively removed. Can be aspirated.

In addition, after the third negative pressure application step, the first negative pressure application step, the second negative pressure application step, and the final negative pressure application step of forming a meniscus of fluid at a maximum pressure lower than the third negative pressure application step. It is preferable to have.
According to the present invention, a good meniscus can be formed by sucking bubbles in the fluid in the final negative pressure application step having a maximum pressure lower than the maximum pressure in the first to third negative pressure application steps. .

  In order to achieve the above object, the present invention provides a fluid suction device for sucking fluid from a plurality of nozzle openings of a fluid ejecting head, the cap member covering the nozzle surface of the fluid ejecting head, and a connection to the cap member A sealed container, a negative pressure generating means for creating a negative pressure inside the sealed container, and a negative pressure control valve interposed between the cap member and the sealed container. A first negative pressure application operation in which the pressure in the space to be formed is set to a predetermined maximum pressure and the fluid in the nozzle opening is sucked, and the maximum pressure is lower than the first negative pressure application operation, and at the time of rising and falling The second negative pressure application operation in which the pressure change per unit time is steeper than that of the first negative pressure application operation, and the fluid in the nozzle opening with the pressure in the space set to the maximum pressure equal to the first negative pressure application operation. Sucking third Characterized in that the pressure application operation, the negative pressure application operation having performed.

  In the present invention, the inside of the sealed container is brought into a negative pressure state by the negative pressure applying means, and is formed between the nozzle surface and the cap member by the action of the negative pressure control valve disposed between the sealed container and the cap member. The desired space can be brought into a desired negative pressure state. When the inside of the space formed between the nozzle surface and the cap member is in a negative pressure state, fluid is sucked from each nozzle opening to the cap member. A part of bubbles in the fluid ejecting head are discharged by the first negative pressure applying operation, and the bubbles (micro bubbles) remaining in the fluid ejecting head are moved by the second negative pressure applying operation to move other bubbles. The integrated and enlarged bubbles are discharged by the third negative pressure application operation.

  As described above, the air bubbles mixed in the fluid ejecting head can be reliably sucked by the intermittent suction operations by the first to third negative pressure application operations having different maximum pressures (maximum negative pressure values to be applied). . When sucking bubbles, bubbles that are somewhat larger than microbubbles are easier to escape. In addition, since there is a tendency that a change (flow / stop) in the flow of the fluid tends to come off, the suction operation is divided into first to third negative pressure application operations, and the suction is intermittently performed. In the present invention, the maximum pressure is lower than the first negative pressure application operation between the first negative pressure application operation and the third negative pressure application operation, and the pressure change per unit time at the rise and fall is the first Since the second negative pressure application operation that is steeper than the first negative pressure application operation is provided, the second negative pressure application operation facilitates the concentration growth of microbubbles and sucks the fluid, thereby mixing in the fluid ejecting head. The removed air bubbles can be surely removed by suction.

  Thereby, clogging of the nozzle opening due to the mixing of bubbles into the fluid can be prevented. Therefore, the ejection characteristics of each fluid ejecting head can be confirmed accurately, and a fluid ejecting head having a good ejecting function can be manufactured.

  Further, the retry rate (refilling rate to the fluid ejecting head) can be reduced, and the processing time can be shortened, thereby improving the productivity.

It is preferable that a plurality of second negative pressure application operations are provided between the first negative pressure application operation and the third negative pressure application operation.
According to the present invention, by providing a plurality of second negative pressure application operations that are temporally adjacent between the first negative pressure application operation and the third negative pressure application operation, the bubbles in the fluid ejecting head can be reliably and It can be quickly aspirated.

In addition, in the negative pressure application operation, after the third negative pressure application operation, the fluid meniscus is set at a maximum pressure lower than the first negative pressure application operation, the second negative pressure application operation, and the third negative pressure application operation. It is preferable that a final negative pressure application operation to be formed is included.
According to the present invention, bubbles in the fluid are sucked in the final negative pressure application operation having a maximum pressure lower than the maximum pressure of the first negative pressure application operation, the second negative pressure application operation, and the third negative pressure application operation. Thus, a good meniscus can be formed.

The present invention is characterized by having the above-described fluid suction method in a print inspection of a fluid ejecting head having a plurality of nozzle openings for ejecting fluid.
Since the print inspection of the present invention has the above-described fluid suction method, clogging of the nozzle openings can be prevented, and a uniform amount of ejection can be performed from each nozzle opening, and fluid ejection caused by missing dots It is possible to prevent a decrease in print inspection accuracy of the head. Thereby, a fluid ejecting head having good ejecting characteristics can be manufactured.

  Hereinafter, an embodiment of a fluid suction 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 the manufacturing process of the ink jet recording apparatus, in order to confirm and adjust the ejection characteristic of the fluid from the nozzle opening, a print inspection (ejection characteristic inspection) is performed with the fluid ejecting head alone before being incorporated into the ink jet recording apparatus. Yes. Such an inspection is performed by using an inspection solution having properties similar to those of the ink used for implementation, and is performed by ejecting the inspection solution onto a recording sheet. At this time, if air bubbles are mixed in the test solution, the nozzle opening may be clogged and the ejection state will deteriorate, and the ejection state of the fluid ejection head will be checked accurately, and the ejection characteristics will be adjusted appropriately. It becomes difficult to do. Therefore, it is necessary to discharge the bubbles from the fluid ejecting head at a stage before the inspection.
A fluid suction device described below has a function of sucking a test solution from a fluid ejecting head for the purpose of discharging bubbles mixed in a test solution filled in a fluid ejecting head to be inspected.

"Fluid suction device"
FIG. 1 is an explanatory diagram showing a schematic configuration of a fluid suction device showing an example of the present embodiment.
The fluid suction device 1 includes a cap unit 2 that seals the nozzle forming surface 33A of the fluid ejecting head 30, and a negative pressure generating unit 4 that generates a negative pressure in the space K formed by the nozzle forming surface 33A and the cap unit 2 ( Negative pressure generating means), and a negative pressure control valve 20 interposed between the cap unit 2 and the negative pressure generating unit 4.

The cap unit 2 includes a rectangular cap case 6 having an open upper surface and a cap member 8 made of a flexible material such as a rubber material housed in the cap case 6. The upper edge side of the cap case 6 protrudes slightly.
A fluid absorbing material 10 made of a porous material is housed in the inner bottom portion of the cap member 8. Further, a suction port 12 is provided in the bottom portion 6 a of the cap case 6 so as to penetrate the cap case 6 and the cap member 8. A discharge tube 14 is connected to the suction port 12, and a desiccator 16 described later is disposed on the discharge side.

  The negative pressure generating unit 4 includes a desiccator 16 (sealed container) and a vacuum pump 18. The desiccator 16 is disposed at the discharge side end of the discharge tube 14 and has a function of storing the test solution sucked from the fluid ejecting head 30 inside. The vacuum pump 18 is connected above the desiccator 16 and makes the sealed space in the desiccator 16 have a negative pressure. The connection position of the vacuum pump 18 is a position where the test solution stored in the desiccator 16 is not sucked.

  The negative pressure control valve 20 is disposed in the discharge tube 14 between the suction port 12 of the cap case 6 and the desiccator 16. The negative pressure control valve 20 employs, for example, an electromagnetic valve that can be electrically controlled to open and close. The negative pressure control valve 20 is opened and closed by a control unit (not shown). The command signal is supplied. By opening or closing the valve based on the command signal of the control unit, the discharge tube 14 is opened or closed, and the negative pressure applied to the space K is controlled.

  The control unit that supplies a signal to the negative pressure control valve 20 has a function of controlling the opening and closing of the negative pressure control valve 20 based on a suction sequence that will be described later, and also the operation and non-operation of the vacuum pump 18. It also has a function to control.

The fluid suction device 1 having such a configuration makes the inside of the desiccator 16 a constant negative pressure state (for example, −100 KPa) by the action of the vacuum pump 18, and opens the negative pressure control valve 20 in this state. A negative pressure is applied to the space K formed between the nozzle forming surface 33A and the cap member 8. That is, the test solution is forcibly discharged from the fluid ejecting head 30 with the space K in a negative pressure state.
It should be noted that the negative pressure applied in the space K can be adjusted by operating the negative pressure control valve 20.

  In the above-described configuration, the suction operation (negative pressure application operation) of the test solution for discharging bubbles in the fluid ejecting head 30 described later causes the cap member 8 to be in close contact with the nozzle plate 33 of the fluid ejecting head 30 and the vacuum. This is performed with the pump 18 being operated. That is, by opening the negative pressure control valve 20 in this state, a negative pressure is applied to the inside (space K) of the cap member 8, and bubbles are discharged from the nozzle opening 32 together with the test solution.

[Fluid ejecting head]
Hereinafter, the configuration of the fluid ejection head to be inspected will be described in detail with reference to FIG. FIG. 2 is a cross-sectional view illustrating a part of the fluid ejecting head.
The fluid ejecting head 30 includes a head body 34, a flow path forming unit 37 including a vibration plate 35, a flow path forming substrate 36, and a nozzle plate 33. The nozzle openings 32 for ejecting ink are formed in the nozzle plate 33, and the lower surface of the nozzle plate 33 is a nozzle forming surface 33A. The flow path forming unit 37 is a unit in which the vibration plate 35, the flow path forming substrate 36, and the nozzle plate 33 are laminated and joined together with an adhesive or the like.

  The fluid ejecting head 30 includes, for example, a housing space 38 formed in the head main body 34 corresponding to the nozzle opening 32 of the fluid ejecting head 30, and a drive unit 39 disposed in the housing space 38. The drive unit 39 includes a plurality of piezoelectric elements 40, a fixing member 41 that supports the upper end of the piezoelectric elements 40, and a flexible cable 42 that supplies a drive signal to the piezoelectric elements 40. The piezoelectric element 40 is provided so as to correspond to each of the plurality of nozzle openings 32.

  In addition, an ink flow path 43 through which ink from an ink cartridge (not shown) flows and a flow path forming unit 37 (a vibration plate 35, a flow path forming substrate) are formed inside the head main body 34 and incorporated in an ink jet recording apparatus. 36 and the nozzle plate 33) and connected to the ink flow path 43, an ink supply port 45 formed by the flow path forming unit 37 and connected to the reservoir 44, and flow path formation. A pressure chamber 46 formed by the unit 37 and connected to the ink supply port 45 is provided. A plurality of pressure chambers 46 are provided so as to correspond to the plurality of nozzle openings 32. Each of the plurality of nozzle openings 32 is connected to each of the plurality of pressure chambers 46.

  The head body 34 is made of synthetic resin. The diaphragm 35 is obtained by laminating an elastic film on a metal support plate such as stainless steel. An island portion 47 to be joined to the lower end of the piezoelectric element 40 is formed at a portion corresponding to the pressure chamber of the vibration plate 35. At least a part of the diaphragm 35 is elastically deformed in accordance with the driving of the piezoelectric element 40. A compliance portion 48 is formed between the vibration plate 35 and the vicinity of the lower end of the ink flow path 43.

  The flow path forming substrate 36 has recesses for forming respective spaces for the reservoir 44, the ink supply port 45, and the pressure chamber 46 that connect the lower end of the ink flow path 43 and the nozzle opening 32. In the present embodiment, the flow path forming substrate 36 is formed by anisotropically etching silicon.

  The nozzle plate 33 has a plurality of nozzle openings 32 formed at a predetermined interval (pitch) in a predetermined direction. The nozzle plate 33 of the present embodiment is a plate-like member formed of a metal such as stainless steel.

  In particular, when the lower fluid ejecting head 30 is used as a color filter, in order to eject a plurality of different types of ink (for example, yellow, magenta, cyan, and black), an independent ink flow path for each type of ink. A plurality of 43 are provided. FIG. 3 shows an arrangement example of the nozzle opening rows 49 on the nozzle forming surface 33A. Different ink types mean not only the apparent color difference, but also the types and ratios of the ink components. Each nozzle opening row 49 includes a plurality of nozzle openings 32.

FIG. 4 shows the introduction needle unit 51 of the fluid ejecting head 30. FIG. 4 is a simplified view of the fluid ejecting head shown in FIG.
As shown in FIG. 4, the fluid ejecting head 30 has an introduction needle unit 51 that erects the ink supply needle 50 </ b> A, and the ink supply needle 50 </ b> A is provided corresponding to the ink flow path 43. The ink supply needle 50A is a hollow needle-shaped member molded from a synthetic resin, and its internal space is introduced with ink in an ink cartridge that is detachably mounted when incorporated as an ink jet recording apparatus. This is a needle flow path 53. An introduction hole 54 that communicates with the needle flow path 53 is formed at the tip of the ink supply needle 50A. When the ink supply needle 50A is inserted into the ink cartridge, the ink supply needle 50A is inserted into the ink cartridge through the introduction hole 54. The ink is introduced into the needle channel 53.

  The introduction needle unit 51 is molded of a synthetic resin in the same manner as the ink supply needle 50A, and the needle channel 53 corresponding to the ink supply needle 50A is formed therein as described above. The upstream end portion of the needle channel 53 has a funnel-like diameter expanded toward the introduction needle mounting side. The ink supply needle 50 </ b> A is fixed on the head main body 34 by welding or the like in a state where the position of the downstream opening of the needle flow path 53 is overlapped with the upstream opening of the ink flow path 43. Thereby, the ink flow path 43 of the head main body 34 and the needle flow path 53 of the ink supply needle 50A communicate in a liquid-tight state.

  With such a configuration, the ink from the ink cartridge flows into the ink flow path 43 through the ink supply needle 50A. The ink flow paths 43 independent for each type of ink are connected to a plurality of pressure chambers 46, respectively. Each pressure chamber 46 is connected to a nozzle opening row 49 including a plurality of nozzle openings 32. Therefore, the ink droplets pushed out from the pressure chamber 46 by the vibration of the piezoelectric element 40 are ejected from the nozzle openings 32 of the nozzle opening row 49.

  As described above, the ejection characteristic test performed on the fluid ejection head 30 having such a configuration uses a test solution having the same properties as the ink that is actually used. Therefore, in the pre-inspection stage, an operation of filling the empty fluid ejecting head 30 with the inspection solution is performed.

[Fluid filling device]
FIG. 5 shows a schematic configuration of a fluid filling device for filling the fluid ejecting head with the test solution.
The fluid filling device 60 of the present embodiment includes a liquid storage tank 61 that stores a test solution, and a fluid supply jig that supplies the test solution sent from the liquid storage tank 61 via the supply tube 62 to the fluid ejection head 30. 63. The fluid supply jig 63 is provided with a plurality of mounting portions 64 that can mount the respective ink supply needles 50 </ b> A of the fluid ejecting head 30. The internal space of each mounting portion 64 includes a storage chamber 65 that temporarily stores the test solution from the liquid storage tank 61 and a supply port 66 that communicates with the storage chamber 65. The ink is introduced into the introduction hole 54 (refer to FIG. 4 as appropriate) of the ink supply needle 50 </ b> A locked to the mounting portion 64.

  In this way, the test solution from the liquid storage tank 61 is filled into the fluid ejecting head 30 via the fluid filling device 60. As described above, the test solution in the fluid filling device 60 flows into the ink flow path 43 through the ink supply needle 50A. Each ink flow path 43 is connected to a plurality of pressure chambers 46. In addition, since each nozzle opening row 49 is connected to each pressure chamber 46, droplets pushed out from the pressure chamber 46 are ejected from the nozzle openings 32 of the nozzle opening row 49.

  At the time of printing, the piezoelectric element 40 expands and contracts, thereby changing the volume of the pressure chamber 46 and causing pressure fluctuation in the test solution in the pressure chamber 46. As a result, droplets are ejected from the nozzle openings 32.

  In the inspection, air bubbles remain in the inspection solution filled in the fluid ejecting head 30 because the inspection solution pressurized in the pressure chamber 46 is ejected as droplets from the nozzle openings 32 onto the recording paper for printing. In this case, the normal flow of the test solution may be hindered, and the normal test solution may not be ejected from the nozzle opening 32. In this case, the fluid suction device 1 according to the present invention described above is used, and it is necessary to forcibly discharge the test solution (bubbles) by the fluid suction device 1.

(Fluid suction operation)
Hereinafter, the fluid suction operation (bubble discharge process) of the fluid ejecting head 30 using the fluid suction device 1 will be described with reference to the flowchart of the fluid suction operation shown in FIG. 6 and the suction sequence shown in FIG. In FIG. 7, the vertical axis represents applied pressure (KPa), and the horizontal axis represents time (sec). Moreover, in description, FIGS. 1-5 is referred suitably.
In the present embodiment, the suction operation is performed by performing opening / closing control of the negative pressure control valve based on the suction sequence of FIG.

  First, in step S <b> 1, upon receiving a suction process command, the fluid ejecting head 30 moves onto the cap unit 2, and the nozzle forming surface 33 </ b> A is sealed by the cap member 8. In this sealed state, a sealed space K is formed between the nozzle forming surface 33 </ b> A and the cap member 8.

  In step S2, the vacuum pump 18 is driven to bring the desiccator 16 into a negative pressure state of about −100 KPa.

  In step S3, the negative pressure control valve 20 is opened by a drive signal from the control unit, and a negative pressure having a maximum negative pressure of about −80 KPa is applied to the sealed space K (first negative pressure applying step). By opening the negative pressure control valve 20, the negative pressure accumulated in the desiccator 16 is applied to the sealed space K via the discharge tube 14, and the negative pressure is applied to the nozzles of the fluid ejecting head 30. It acts as a suction force from the opening 32.

  That is, the inside of the sealed space K is gradually reduced by opening the negative pressure control valve 20, and the test solution corresponding to the pressure change is sucked. If the negative pressure control valve 20 is closed while the vacuum pump 18 is driven, the negative pressure state in the sealed space K is gradually released, and the suction amount is reduced accordingly. In this way, the test solution is forcibly sucked from the fluid ejecting head 30. Then, the test solution sucked into the cap member 8 is discharged into the desiccator 16 through the discharge tube 14.

  In step S4, the negative pressure control valve 20 is opened again by a drive signal from the control unit, and a negative pressure having a maximum negative pressure of about −60 KPa is applied to the sealed space K (second negative pressure applying step). . Immediately after that, by closing the negative pressure control valve 20, a pressure change (flow) with a sharper pressure change per unit time at the rise and fall of the sealed space K than at step S <b> 3. Can be given. In the first negative pressure application process in step S3, it takes 3 seconds to reach the maximum negative pressure, whereas in this step, the opening / closing operation of the negative pressure control valve 20 is achieved within 1 second. . This is because the maximum negative pressure (attainment pressure) is set lower than that in the first application step, so that an instantaneous rise is possible. This step is performed in order to move bubbles remaining in the fluid ejecting head 30 without being discharged in the suction operation of step S3. In this way, the rapid growth of the flow of the test solution (fluid) is promoted to promote the concentration growth of microbubbles.

  In step S5, the negative pressure control valve 20 is held for a predetermined time with the valve closed, and a negative pressure non-application operation is performed on the sealed space K (negative pressure non-application process). Here, the holding state is maintained for the same period (about 1 second) as the operation period of the second negative pressure applying step in step S4, and the flow of the test solution is stopped. In this way, the microbubbles in the test solution are further concentrated and grown.

Subsequently, Step S4 and Step S5 are performed again, and a series of operations from the second negative pressure application process to the negative pressure non-application process is performed twice in succession.
When there are many residual bubbles in the fluid ejecting head 30, the series of operations from step S4 to step S5 may be performed twice or more continuously.

That is, the ink flow path 43 in the fluid ejecting head 30 includes a pressure chamber 46, a reservoir 44, and the like, and has a complicated structure. For this reason, it is difficult for air bubbles caught in the stepped portion in the ink flow path 43 to be discharged in the first negative pressure applying step (step S3). Further, since the test solution is initially filled in the empty fluid ejecting head 30, bubbles may remain in a state of sticking to the wall portion in the ink flow path 43, and these bubbles are also difficult to be discharged. . Therefore, by repeating the operations from step S4 to step S5 a plurality of times, the flow of the test solution is changed (flow / stopped), thereby causing the test solution in the fluid ejecting head 30 to pulsate, and the fluid ejecting head 30. The bubbles remaining inside become a certain size together with other bubbles. When discharging bubbles, bubbles having a certain size are easier to escape than microbubbles.
Step S5 includes an operation of waiting for the spontaneous disappearance of extremely small bubbles.

  In step S6, the negative pressure control valve 20 is opened, and a negative pressure having a maximum negative pressure of about −80 KPa is applied to the sealed space K (third negative pressure applying step). Here, the period during which the inside of the sealed space K is held at the specified maximum negative pressure −80 KPa is secured longer than the first negative pressure applying step in step S3. Specifically, the maximum negative pressure holding period in the first negative pressure applying process is 3 seconds, whereas the third negative pressure applying process has a holding period of 5 seconds. In this way, by maintaining the maximum negative pressure state to some extent, a large amount of test solution can be sucked and the residual bubbles in the fluid ejecting head 30 can be reliably removed. That is, step S6 is an operation for discharging the integrated residual bubbles by giving several pulsation operations to the test solution in the repeated operation of steps S4 and S5.

  In the present embodiment, the suction time in the third negative pressure application step (a period during which the inside of the sealed space K is held at the specified maximum negative pressure−80 KPa) is ensured longer than that in the first negative pressure application step. However, it may be the same time as the first negative pressure applying step.

  In step S7, a maximum negative pressure of −40 KPa is applied to the sealed space K (final negative pressure application step). Here, the rise of the pressure change in the sealed space K is more rapid than in the first negative pressure applying step in step S3, and the state immediately shifts to the steady state. In addition, the maximum negative pressure holding period in this step is as long as 15 seconds. As described above, a meniscus for preparation for ejection is formed in the nozzle opening 32 while preventing the test solution from foaming by suctioning from the fluid ejection head 30 at a low pressure for a long period of time.

  In step S8, driving of the suction pump 18 is stopped, and the sealed space K is opened to the atmosphere, thereby completing the suction operation.

  As described above, the negative pressure control valve 20 is intermittently operated, and the second negative pressure application step and the negative pressure non-application step are continuously performed a plurality of times, thereby pulsating the test solution of the fluid ejecting head 30. Thus, residual bubbles in the fluid ejecting head 30 can be reliably discharged. That is, the maximum pressure is lower than the first negative pressure application step between the first negative pressure application step and the third negative pressure application step, and the pressure change per unit time at the rise and fall is the first negative pressure. By providing the second negative pressure application process (and the negative pressure non-application process) that is steeper than the pressure application process multiple times, the concentrating growth of residual bubbles is promoted, and it is easy to discharge the bubbles in the third negative pressure application process. is doing. Thereby, the air bubbles mixed in the fluid ejecting head 30 can be reliably sucked and removed.

In addition, when the empty fluid ejection head 30 to be inspected is replaced with the fluid suction device 1, bubbles may be mixed in the fluid supply jig 63. However, the fluid suction device 1 according to the present embodiment. Accordingly, the bubbles in the fluid supply jig 63 can also be discharged.
In this way, by performing the second negative pressure application step and the negative pressure non-application step for quickly opening and closing the negative pressure control valve 20 between the first negative pressure application step and the third negative pressure application step, The negative pressure in the sealed space K changes greatly so as to pulsate. As a result, the residual bubbles in the fluid ejecting head 30 can be discharged quickly and reliably. As a result, each nozzle opening 32 of the fluid ejecting head 30 can be reliably and uniformly filled with the test solution, and the test solution can be ejected from each nozzle opening 32 in a desired ejection amount.
Further, the operation from step S3 to step S6 may be repeated several times.

The print inspection of the fluid ejecting head 30 includes a fluid suction method using the fluid suction device 1 and is performed on the fluid ejecting head 30 from which bubbles in the test solution are completely eliminated. In this print inspection, by checking the ejection state of the fluid ejecting head 30 such as whether or not the liquid droplets are reliably ejected from the nozzle openings 32 of the fluid ejecting head 30, the ejection is performed so that proper ejection is possible. This is done to adjust the characteristics.
For example, various confirmations and adjustments are performed, such as setting the amount of change in the voltage of the ejection pulse applied to the piezoelectric element 40 to set the ejection characteristics to be optimal. In such an inspection, by using the fluid ejecting head 30 in which bubbles are not mixed in the inspection solution, the inspection accuracy is improved and the fluid ejecting head 30 having high reliability can be provided.

  The preferred embodiments according to the present invention have been described above with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to such examples, and the above embodiments may be combined. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

For example, the negative pressure application intensity, the negative pressure application time, the negative pressure non-application time, and the like in the suction sequence can be appropriately changed.
The fluid suction device 1 is not only used in the print inspection, but can also be provided in the ink jet recording apparatus. By performing the cleaning process of the fluid ejecting head 30 using the fluid suction device 1, nozzle clogging can be prevented and stable ejection can be performed for a long period of time, and good printing can be performed.

1 shows a schematic configuration of a fluid suction device according to an embodiment of the present invention. A part of the fluid ejection head is shown. An arrangement example of nozzle opening rows on the nozzle formation surface of the fluid ejecting head is shown. 2 shows an introduction needle unit of a fluid ejection head. 1 shows a schematic configuration of a fluid filling apparatus. It is a flowchart figure of the fluid suction operation using the fluid suction apparatus which concerns on one Embodiment of this invention. It is a figure which shows the suction sequence by the fluid suction apparatus which concerns on one Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fluid suction apparatus, 4 ... Negative pressure generation unit (negative pressure generation means), 8 ... Cap member, 16 ... Desiccator (sealed container), 20 ... Negative pressure control valve, 30 ... Fluid ejection head, 32 ... Nozzle opening, 33A ... Nozzle forming surface (nozzle surface), K ... Sealing (space)

Claims (7)

A fluid suction method for sucking fluid from a plurality of nozzle openings of a fluid ejection head,
A first negative pressure applying step of sucking a fluid in the nozzle opening by setting a pressure in a space formed by a nozzle surface of the fluid ejecting head and a cap member covering the nozzle surface to a predetermined maximum pressure;
A second negative pressure application step in which the maximum pressure is lower than that in the first negative pressure application step, and the pressure change per unit time at the time of rising and falling is steeper than that in the first negative pressure application step;
And a third negative pressure applying step of sucking the fluid in the nozzle opening by setting the pressure in the space to a maximum pressure equal to that of the first negative pressure applying step.   The fluid suction method according to claim 1, wherein a plurality of the second negative pressure application steps are provided between the first negative pressure application step and the third negative pressure application step.   After the third negative pressure application step, a final negative pressure that forms a meniscus of the fluid at a maximum pressure lower than that of the first negative pressure application step, the second negative pressure application step, and the third negative pressure application step. The fluid suction method according to claim 1, further comprising an applying step. A fluid suction device for sucking fluid from a plurality of nozzle openings of a fluid ejection head,
A cap member covering the nozzle surface of the fluid ejecting head;
A sealed container connected to the cap member;
Negative pressure generating means for making the inside of the sealed container negative,
A negative pressure control valve interposed between the cap member and the sealed container,
A first negative pressure application operation for sucking a fluid in the nozzle opening by setting a pressure in a space formed by the nozzle surface and the cap member to a predetermined maximum pressure;
A second negative pressure application operation in which the maximum pressure is lower than that of the first negative pressure application operation, and the pressure change per unit time at the time of rising and falling is steeper than that of the first negative pressure application operation;
A negative pressure application operation is performed, wherein the pressure in the space is set to a maximum pressure equal to the first negative pressure application operation, and a third negative pressure application operation for sucking the fluid in the nozzle opening is performed. Fluid suction device.   The fluid suction device according to claim 4, wherein a plurality of the second negative pressure application operations are provided between the first negative pressure application operation and the third negative pressure application operation.   In the negative pressure application operation, after the third negative pressure application operation, the first negative pressure application operation, the second negative pressure application operation, and the maximum pressure lower than the third negative pressure application operation, The fluid suction device according to claim 4, further comprising a final negative pressure application operation for forming a meniscus. In a print inspection method for a fluid ejecting head having a plurality of nozzle openings for ejecting fluid,
A printing inspection method comprising the fluid suction method according to claim 1.

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