JP2020075390A - Method of inspecting liquid injection head - Google Patents

Abstract

To provide a method of inspecting a liquid injection head that can inspect injection characteristics easily and correctly .SOLUTION: An method of inspecting a liquid injection head uses a liquid injection head comprising: a channel in which a fluid flows from a first channel port to a second channel port; and a discharge port which is provided in the channel between the first channel port and the second channel port and discharges part of the fluid flowing in the channel to outside, to open the first channel port and close the second channel port so as to flow a fluid at a prescribed flow rate from the first channel port to the channel, thus measuring a first pressure which is a pressure of the fluid which flows from the first channel port to the discharge port. The method closes the first channel port and opens the second channel port so as to flow the fluid at a prescribed flow rate from the second channel port to the channel, thus measuring a second pressure which is a pressure of the fluid flowing from the second channel port to the discharge port. The method calculates a pressure ratio on the basis of the first pressure and the second pressure, and determines whether there is leakage of the fluid flowing in the channel from the first channel port to the second channel port or not on the basis of the pressure ratio.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a method for inspecting a liquid jet head including a flow path through which a fluid flows.

  A liquid ejecting head is used to eject a liquid droplet in a target, and the liquid ejecting head includes a flow path through which the liquid flows. At the time of ejecting the liquid, a part of the liquid flowing through the flow path is discharged to the outside, so that the liquid is ejected from the liquid ejecting head to the object.

  Various studies have been made to inspect the ejection characteristics of a liquid ejection head. Specifically, when inspecting the ejection characteristics of a liquid ejection head for recording use, an inspection hole is used to detect liquid leakage (see, for example, Patent Document 1).

JP, 2017-185733, A

  Various examinations have been made to inspect the ejection characteristics of the liquid ejecting head, but there is room for improvement in the existing inspection because the procedure is complicated and the accuracy is not sufficient.

  Therefore, it is desired to provide a method for inspecting a liquid ejecting head that can easily and accurately inspect the ejection characteristics.

  A method for inspecting a liquid ejecting head according to an embodiment of the present disclosure provides a flow path in which a fluid flows from a first flow path opening to a second flow path opening and a flow path between the first flow path opening and the second flow path opening. A liquid jet head provided with a discharge port for discharging a part of the fluid flowing through the flow path to the outside is used to open the first flow path opening and close the second flow path opening from the first flow path opening. The first pressure, which is the pressure of the fluid flowing from the first flow path port toward the discharge port, is measured by flowing the fluid at a predetermined flow rate in the flow path, and the first flow path port is closed and the second flow path port is opened. While flowing the fluid from the second flow passage port to the flow passage at a predetermined flow rate, the second pressure, which is the pressure of the fluid flowing from the second flow passage opening toward the discharge port, is measured, and the first pressure and the second pressure are measured. The pressure ratio is calculated based on the pressure ratio, and the presence or absence of leakage of the fluid flowing through the flow path from the first flow path opening to the second flow path opening is determined based on the pressure ratio.

  According to the liquid ejecting head inspection method of the embodiment of the present disclosure, the flow path includes a flow path in which the fluid flows from the first flow path opening toward the second flow path opening and a part of the fluid is discharged to the outside from the discharge opening. Since the liquid ejection head is used to measure the first pressure and the second pressure and the pressure ratio is calculated, the presence or absence of fluid leakage is determined based on the pressure ratio. Can be inspected easily and accurately.

FIG. 3 is a plan view illustrating a configuration of a liquid ejecting head used in the liquid ejecting head inspection method according to the embodiment of the present disclosure. FIG. 6 is a plan view for explaining a flow path provided in the liquid jet head. 6 is a flowchart for explaining a method (preliminary preparation procedure) for inspecting a liquid jet head. 6 is a flowchart for explaining a method of inspecting a liquid ejecting head (procedure for determining internal leak). It is a figure showing correlation CP1 of flow volume M and pressure P1. It is a figure showing correlation CP2 of flow volume M and pressure P2. It is a figure showing correlation CR of flow volume M and pressure ratio R. 8 is a flowchart for explaining a first modification example regarding the method for inspecting the liquid jet head. 9 is a flowchart for explaining a second modification example regarding the method for inspecting the liquid ejecting head.

Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. The order of description is as follows.

1. Inspection method of liquid jet head 1-1. Configuration of liquid jet head 1-2. Inspection procedure of liquid jet head 1-3. Action and effect 2. Modification

<1. Liquid ejection head inspection method>
A method for inspecting a liquid jet head according to an embodiment of the present disclosure will be described.

  The liquid ejecting head used in the method for inspecting the liquid ejecting head ejects liquid onto an object, for example. The application of the liquid ejecting head is not particularly limited as long as the liquid ejecting head is required to eject the liquid.

  The liquid ejecting head described here ejects a recording liquid onto a recording medium to record an image on the recording medium. That is, the liquid jet head is used, for example, in a printer (so-called inkjet printer) which is a liquid jet recording layer device. The type of recording medium is not particularly limited, and examples thereof include paper and film.

<1-1. Liquid jet head configuration>
FIG. 1 shows a plan configuration of an inkjet head 100, which is a specific example of a liquid jet head. FIG. 2 shows a plan configuration corresponding to FIG. 1 in order to explain the flow path L provided in the inkjet head 100. Note that FIG. 2 also shows pressure sensors 60 and 70 used in an inspection process of the inkjet head 100 described later.

  The inkjet head 100 employs a circulation system that uses a recording liquid (ink 1) that is circulated by a circulation mechanism. The inkjet head 100 is, for example, a side shoot type in which the ink 1 is ejected in a direction intersecting with the extending direction of a plurality of channels described later.

  Specifically, the inkjet head 100 includes, for example, as shown in FIGS. 1 and 2, a head chip 10, an electronic control panel 30, an introduction port 40 having an introduction port 40T (first flow path port), And a discharge port 50 having a discharge port 50T (second flow path port).

  In this inkjet head 100, a flow path L for the ink 1 from the introduction port 40T to the discharge port 50T is formed, and the nozzle hole 11H (emission port) is formed in the flow path L between the introduction port 40T and the discharge port 50T. ) Is provided. In this flow path L, when the ink 1 is supplied from the introduction port 40T to the flow path L, the ink 1 flows from the introduction port 40T toward the discharge port 50T, and a part of the ink 1 is needed (recording). At the time), it is discharged from the nozzle hole 11H to the outside. As will be described later, in the inspection process of the inkjet head 100, the inspection fluid F is supplied to the flow path L. In FIG. 2, the flow path L is indicated by a thick broken line.

  This flow path L includes a flow path L1 from the inlet 40T to the nozzle hole 11H and a flow path L2 from the discharge port 50T to the nozzle hole 11H.

  The head chip 10 ejects the ink 1 onto the recording medium by discharging from the nozzle holes 11H. The head chip 10 includes, for example, a nozzle plate 11, an actuator plate 12, and a cover plate 13, which are sequentially stacked from the side farther from the electronic control board 30.

  The nozzle plate 11 has a nozzle hole 11H which is an ejection port of the ink 1. Here, the nozzle plate 11 has, for example, a plurality of nozzle holes 11H, and the plurality of nozzle holes 11H are arranged, for example, in the left-right direction in FIG. However, in FIG. 1, only one nozzle hole 11H is shown in order to simplify the illustration.

  The actuator plate 12 has, for example, a plurality of channels (not shown) (a plurality of ejection channels into which the ink 1 is introduced and a plurality of dummy channels into which the ink 1 is not introduced). For example, the actuator plate 12 ejects the ink 1 from the ejection channel to the outside via the nozzle hole 11H by electrically changing the internal pressure of the ejection channel into which the ink 1 is introduced at the time of recording. The cover plate 13 has, for example, a plurality of slits (not shown), and allows the ink 1 to be introduced into the actuator plate 12 (a plurality of ejection channels) via the plurality of slits.

  In the inkjet head 100, as described above, the ink 1 introduced from the introduction port 40 (introduction port 40T) flows to the ejection port 50 (ejection port 50T) via the head chip 10. Therefore, the flow path L is formed inside the head chip 10.

  The electronic control board 30 controls the overall operation of the inkjet head 100. The electronic control board 30 includes, for example, a circuit board 31, a drive circuit 32, and a flexible board 33. The circuit board 31 is erected on the head chip 10, for example. The drive circuit 32 is provided on the circuit board 31, for example, and includes an electronic component such as an integrated circuit (IC). The flexible substrate 33 is connected to each of the head chip 10 and the drive circuit 32, for example.

  The introduction port 40 is a tubular component provided with an introduction port 40T, and is connected to one end of the head chip 10 (cover plate 13). The discharge port 50 is a tubular component provided with a discharge port 50T, and is connected to the other end of the head chip 10 (cover plate 13). Each of the introduction port 40 and the discharge port 50 can be connected to, for example, a supply tube or the like (not shown) in order to circulate the ink 1.

<1-2. Liquid ejection head inspection procedure>
Each of FIG. 3 and FIG. 4 shows a flow for explaining the inspection method of the inkjet head 100. However, FIG. 3 shows the flow of the preparatory procedure, and FIG. 4 shows the flow of the internal leak determination procedure.

  5 shows the correlation CP1 between the flow rate M and the pressure P1, and FIG. 6 shows the correlation CP2 between the flow rate M and the pressure P2. FIG. 7 shows the correlation CR between the flow rate M and the pressure ratio R.

  Here, in order to inspect the ejection characteristics of the inkjet head 100, an inspection fluid F and pressure sensors 60, 70 and an unillustrated control board for inspection are used in the interior of the inkjet head 100 (flow path L). It is determined whether or not the fluid F leaks (so-called internal leak). The internal leak occurs, for example, because the actuator plate 12 (dummy channel) is damaged, so that the ink 1 enters the dummy channel where the ink 1 should not originally enter inside the inkjet head 100. To do.

  The pressure sensor 60 is arranged in the vicinity of the introduction port 40 (the introduction port 40T) and measures the pressure (pressure P1) of the fluid F flowing in the flow path L1. The pressure sensor 70 is arranged in the vicinity of the discharge port 50 (discharge port 50T) and measures the pressure (pressure P2) of the fluid F flowing through the flow path L2. The control board controls the pressure sensors 60, 70 and the like, and also performs a series of processes such as an acquisition process, a calculation process, and a determination process described later.

  In the following, a preparatory procedure for performing the internal leak determination procedure will be described, and then the internal leak determination procedure will be described. In this case, refer to FIG. 1 and FIG. 2 already described as needed. It should be noted that a series of processes such as a process for obtaining the correlations CP1, CP2, CR, a process for calculating the pressure ratio R, and a process for determining the presence / absence of internal leak, which will be described below, are performed by the control board described above, for example.

[Preparation procedure]
In the preparatory procedure, the following procedure is sequentially performed using the normal inkjet head 100 in which no internal leak has occurred, as shown in FIG.

  First, while the inlet 40T is opened and the outlet 50T is closed, the fluid F is caused to flow from the inlet 40T to the flow path L, so that the pressure sensor 60 is used to introduce the fluid F near the inlet 40T. The pressure of the fluid F flowing from the opening 40T toward the nozzle hole 11H (pressure P1 as the first pressure) is measured. This pressure P1 is the pressure of the fluid F flowing through the flow path L1. In this case, the operation of measuring the pressure P1 while changing the flow rate M of the fluid F is repeated (step S11). Thereby, as shown in FIG. 5, the correlation CP1 between the flow rate M and the pressure P1 is acquired in advance (step S12).

  The type of the fluid F is not particularly limited as long as it is a substance that can move inside the flow path L by utilizing fluidity, and is, for example, gas such as air and nitrogen gas. To obtain the correlation CP1, for example, the plurality of pressures P1 are measured while changing the flow rate M, and then the approximate straight line N1 is drawn based on the plurality of pressures P1.

  The correlation CP1 is used to grasp the correspondence between the flow rate M and the pressure P1 regarding the normal inkjet head 100 in which the internal leak does not occur in the internal leak determination procedure described later. For example, as shown in FIG. 5, when the pressure P1 is measured when the flow rate M of the fluid F is set to the flow rate MA, if the internal leak does not occur in the inkjet head 100, the pressure P1 corresponds to the flow rate MA. Pressure should be P1A.

  Subsequently, while closing the inlet 40T and opening the outlet 50T, the fluid F is caused to flow from the outlet 50T to the flow path L, so that the pressure sensor 70 is used to discharge the fluid in the vicinity of the outlet 50T. The pressure of the fluid F flowing from the outlet 50T toward the nozzle hole 11H (pressure P2 that is the second pressure) is measured. This pressure P2 is the pressure of the fluid F flowing through the flow path L2. In this case, the operation of measuring the pressure P2 while changing the flow rate M of the fluid F is repeated (step S13). Thereby, as shown in FIG. 6, the correlation CP2 between the flow rate M and the pressure P2 is acquired in advance (step S14).

  The type of fluid F is the same as the type of fluid F used when measuring the pressure P1. When obtaining the correlation CP2, for example, a plurality of pressures P2 are measured while changing the flow rate M, and then an approximate straight line N2 is drawn based on the plurality of pressures P2.

  This correlation CP2 is used to grasp the correspondence between the flow rate M and the pressure P2 regarding the normal inkjet head 100 in which the internal leak does not occur in the internal leak determination procedure described later. For example, as shown in FIG. 6, when the pressure P2 is measured when the flow rate M of the fluid F is set to the flow rate MA, if the internal leak does not occur in the inkjet head 100, the pressure P2 corresponds to the flow rate MA. Pressure P2A to be applied.

  Finally, by calculating the pressure ratio R (= P2 / P1) for each flow rate M based on the above-mentioned correlations CP1 and CP2 (step S15), as shown in FIG. The correlation CR with R is acquired in advance (step S16). As a result, the approximate straight line N3 is obtained, so that the preparatory procedure is completed.

  The correlation CR is used to grasp the correspondence between the flow rate M and the pressure ratio R regarding the normal inkjet head 100 in which the internal leak does not occur in the internal leak determination procedure described later. For example, as shown in FIG. 7, when the pressure ratio R is calculated when the flow rate M of the fluid F is set to the flow rate MA, if the internal leak does not occur in the inkjet head 100, the pressure ratio R will be the flow rate MA. Should be the pressure ratio RA corresponding to

[Procedure for determining internal leak]
In the internal leak determination procedure, the following procedure is sequentially performed using the inkjet head 100 whose presence or absence of the internal leak is unknown, as shown in FIG. In this case, as described above, the correlations CP1, CP2, CR are acquired in advance.

  First, a reference pressure PS, which is a reference for determining the presence or absence of an internal leak, is acquired (step S21). In this case, the flow rate M of the fluid F is determined so as to have a desired value (predetermined flow rate M), and then the pressure ratio R corresponding to the flow rate M is specified based on the above-mentioned correlation CR. The pressure ratio R is set as a reference pressure ratio RS. The reference pressure ratio RS is a pressure ratio R that should be calculated if no internal leak occurs when the fluid F (flow rate M) is passed through the flow path L.

  Subsequently, while opening the inlet 40T and closing the outlet 50T, the fluid F (flow rate M) is caused to flow from the inlet 40T to the flow path L, so that the pressure sensor 60 is used to discharge the nozzle from the inlet 40T. The pressure (pressure P1) of the fluid F flowing toward the hole 11H is measured (step S22). The type of fluid F is the same as the type of fluid F used in the preparatory procedure.

  Subsequently, while closing the inlet 40T and opening the outlet 50T, the fluid F (flow rate M) is caused to flow from the outlet 50T to the flow path L, so that the pressure sensor 70 is used to discharge the nozzle from the outlet 50K. The pressure (pressure P2) of the fluid F flowing toward the hole 11H is measured (step S23). The type of fluid F is the same as the type of fluid F used in the preparatory procedure.

  Then, after calculating the pressure ratio R (= P2 / P1) based on the pressures P1 and P2 (step S24), the presence or absence of internal leak is determined based on the pressure ratio R. Specifically, for example, the pressure ratio R is compared with the reference pressure ratio RS (step S25). As described above, the reference pressure ratio RS is the pressure ratio R that should be calculated if the internal leak does not occur. Therefore, based on the correspondence relationship between the pressure ratio R and the reference pressure ratio RS, The presence or absence of internal leak can be determined. In this case, for example, it is confirmed whether or not the pressure ratio R is within a predetermined range (RS−X ≦ R ≦ RS + X) with respect to the reference pressure ratio RS (step S26). Since the value of X is not particularly limited, it can be arbitrarily set after taking into consideration factors such as measurement errors of the pressures P1 and P2. Here, the value of X is, for example, a value corresponding to 3% of the reference pressure ratio RS.

  When the pressure ratio R is not within the predetermined range with respect to the reference pressure ratio RS (step S26N), the pressure ratio R is significantly different from the reference pressure RS even when the allowable margin (X) is taken into consideration. It is determined that a leak has occurred (step S27).

  In this case, it is considered that one or both of the flow paths L1 and L2 are damaged (for example, a crack is generated) inside the inkjet head 100. If the flow path L1 is damaged, flow path resistance is generated in the flow path L1 and the pressure P1 is reduced. Therefore, the pressure ratio R greatly differs from the reference pressure ratio RS due to the decrease in the pressure P1. If the flow path L2 is damaged, flow path resistance is generated in the flow path L2, and the pressure P2 decreases. Therefore, the pressure ratio R greatly differs from the reference pressure ratio RS due to the decrease in the pressure P2.

  On the other hand, when the pressure ratio R is within the predetermined range with respect to the reference pressure ratio RS (step S26Y), the pressure ratio R is substantially equal to the reference pressure RS in consideration of the allowable margin (X). Therefore, it is determined that the internal leak has not occurred (step S28).

  As a result, the presence or absence of the internal leak is determined based on the pressure ratio R, and the procedure for determining the internal leak is completed.

<1-3. Action and effect>
In this inspection method of the inkjet head 100, the inkjet head 100 including the flow path L through which the fluid F flows from the inlet 40T to the outlet 50T and a part of the fluid F is discharged to the outside from the nozzle hole 11H is used. After the pressures P1 and P2 are measured and the pressure ratio R is calculated, the presence or absence of internal leak is determined based on the pressure ratio R.

  In this case, after the pressure P1 of the fluid F flowing through the first half of the flow path L (flow path L1) and the pressure P2 of the fluid F flowing through the second half of the flow path L (flow path L2) are measured, The presence or absence of internal leak is determined based on the pressure ratio R calculated from the pressures P1 and P2. As a result, the accuracy of the determination is the outside temperature (the temperature of the surrounding environment of the inkjet head 100) and the like as compared with the case where the presence or absence of the internal leak is determined based on the pressure of the fluid F flowing through the entire flow path L. Since it is less likely to be affected by the external disturbance, the accuracy of the determination is improved.

  Moreover, it is not necessary to destroy the inkjet head 100 in order to determine the presence or absence of the internal leak, that is, the leakage of the fluid F due to the internal damage of the inkjet head 100, which is difficult to confirm from the outside. There is no need to newly provide an inspection hole or the like in the inkjet head 100. Thus, the presence or absence of the internal leak can be determined only by performing the simple work of measuring the pressures P1 and P2 and calculating the pressure ratio R after flowing the fluid F through the flow path L.

  Therefore, whether or not an internal leak has occurred in the inkjet head 100 (flow path L) is easily and accurately determined, so that the ejection characteristics of the inkjet head 100 can be easily and accurately inspected.

  In this case, in particular, by incorporating the above-described inspection method into the jet inspection of the inkjet head 100 before shipping, the jet inspection of the inkjet head 100 before shipping can be easily and accurately performed.

  In addition, the reference pressure ratio RS is acquired in advance using the normal inkjet head 100 in which no internal leak occurs, and the pressure ratio R is compared with the reference pressure ratio RS, and the pressure ratio R is the reference pressure ratio. If it is determined that the internal leak is occurring when RS is not within the predetermined range, the pressure ratio R is compared with the pressure ratio R (reference pressure ratio RS) at the normal time to thereby determine the pressure ratio R. Is deviated from the reference pressure ratio RS to an extent exceeding a certain range, it is determined that an internal leak has occurred. Therefore, by performing the simple operation of comparing the pressure ratio R with the reference pressure ratio RS, the presence or absence of the internal leak can be determined with higher accuracy while suppressing the influence of the measurement error and the like, and a higher effect can be obtained. be able to.

  In this case, the correlation CR is acquired in advance using the normal inkjet head 100 in which no internal leak occurs, and the pressure ratio R corresponding to the flow rate M is calculated based on the correlation CR as the reference pressure ratio RS. Then, even if the value of the flow rate M is changed, the normal pressure ratio R (reference pressure ratio RS) corresponding to the changed flow rate M is specified based on the correlation CR. As a result, the reference pressure ratio RS serving as a reference for determining the presence or absence of the internal leak is accurately determined without depending on the value of the flow rate M. Therefore, even if the flow rate M is changed, the presence / absence of an internal leak can be determined with high accuracy, and a higher effect can be obtained.

  If a gas is used as the fluid F, a higher effect can be obtained for the reason described below. That is, when a liquid is used as the fluid F, it is not necessary for the inkjet head 100 (flow path L) before shipping unless an internal leak due to the damage of the flow path L occurs as a result of inspecting the inkjet head 100. Since such a liquid adheres, it is necessary to clean the flow path L to remove the unnecessary liquid. On the other hand, when a gas is used as the fluid F, unlike the case where the liquid is used, the liquid does not adhere to the inkjet head 100 before shipping, and thus the cleaning of the flow path L is not necessary. Therefore, the ejection characteristics of the inkjet head 100 can be easily and accurately inspected without requiring a cleaning process due to unnecessary liquid adhesion, and a higher effect can be obtained.

  In addition to this, when gas is used, the liquid does not adhere to the inkjet head 100 (flow path L), and therefore it is not necessary to consider (process) the liquid when discarding the inkjet head 100 having an internal leak. Therefore, an advantage can be obtained from the viewpoint that the treatment of the liquid is unnecessary.

<2. Modification>
The inspection procedure of the inkjet head 100 described above can be modified in various ways, as described below. In addition, about a series of modified examples demonstrated below, arbitrary 2 or more types may be combined together.

[Modification 1]
As shown in FIGS. 5 to 7, when the correlation CR is acquired based on the correlations CP1 and CP2, the step of determining the presence or absence of the internal leak is performed only once. As described above, the step of determining the presence or absence of the internal leak includes determining the flow rate M of the fluid F so as to obtain the desired flow rate M, and then specifying the reference pressure ratio RS corresponding to the flow rate M. , The step of comparing the pressure ratio R with the reference pressure ratio RS.

  However, the number of steps for determining the presence or absence of the internal leak is not limited to once, and may be two or more. Also in this case, the presence or absence of the internal leak is determined, so that the same effect can be obtained. In this case, in particular, if the step of determining the presence or absence of the internal leak while changing the flow rate M of the fluid F is performed twice or more (for example, three times), the accuracy of the determination is further improved, so that a higher effect is obtained. Obtainable.

[Modification 2]
As shown in FIG. 5, in order to obtain the correlation CP1, an approximate straight line N1 was obtained by measuring a plurality of pressures P1 while changing the flow rate M. Further, as shown in FIG. 6, in order to obtain the correlation CP2, the approximate straight line N2 was obtained by measuring a plurality of pressures P2 while changing the flow rate M.

  However, when the flow rate M is fixed without being changed, that is, when the flow rate M is set to a constant value, for example, in order to obtain the correlation CP1, the pressure P1 corresponding to the flow rate M that is a specific value is obtained. It is also possible to measure only the pressure P2 and to measure the pressure P2 corresponding to the flow rate M that is a specific value in order to obtain the correlation CP2. Also in this case, since the pressure ratio R (reference pressure ratio RS) corresponding to the flow rate M is specified by specifying the pressures P1 and P2 corresponding to the flow rate M, the same effect can be obtained. ..

[Modification 3]
In FIG. 4, the presence or absence of internal leak was determined based on only the pressure ratio R. However, as shown in FIG. 8 corresponding to FIG. 4, after determining the presence or absence of the internal leak based on the pressure ratio R, the presence or absence of the internal leak is further determined based on both the pressures P1 and P2. Good.

  Specifically, after performing the preparatory procedure (FIG. 3) and the internal leak determination procedure (FIG. 4) based on the pressure ratio R, first, a reference serving as a reference for determining the presence or absence of the internal leak. The pressures P1S and P2S are acquired (step S31). In this case, the pressure P1 corresponding to the flow rate M is specified based on the correlation CP1 to set the pressure P1 as the reference pressure P1S, and the pressure P2 corresponding to the flow rate M is specified based on the correlation CP2. By doing so, the pressure P2 becomes the reference pressure P2S. The reference pressure P1S is the pressure P1 that should be measured if no internal leak occurs when the fluid F (flow rate M) flows through the flow path L1, and the reference pressure P2S is the flow path L2. It is the pressure P2 that should be measured if no internal leak occurs when the fluid F (flow rate M) is passed.

  Then, the presence or absence of internal leak is determined based on the pressure P1. Specifically, for example, the pressure P1 is compared with the reference pressure P1S (step S32). As described above, the reference pressure P1S is the pressure P1 that should be measured if the internal leak does not occur. Therefore, the presence or absence of the internal leak is determined based on the correspondence between the pressure P1 and the reference pressure P1S. Can be determined. In this case, for example, it is confirmed whether or not the pressure P1 is within a predetermined range (P1S-Y ≦ P1 ≦ P1S + Y) with respect to the reference pressure P1S (step S33). The value of Y is not particularly limited, and can be arbitrarily set, for example, in consideration of factors such as a measurement error of the pressure P1. Here, the value of Y is, for example, a value corresponding to 3% of the reference pressure P1S.

  If the pressure P1 is not within the predetermined range with respect to the reference pressure P1S (step S33N), the pressure P1 is significantly different from the reference pressure P1S even when the allowance margin (Y) is taken into consideration, so that internal leakage occurs. (Step S34).

  On the other hand, when the pressure P1 is within the predetermined range with respect to the reference pressure P1S (step S33Y), the presence or absence of the internal leak is continuously determined based on the pressure P2. Specifically, for example, the pressure P2 is compared with the reference pressure P2S (step S35). As described above, the reference pressure P2S is the pressure P2 that should be measured if the internal leak does not occur. Therefore, the presence or absence of the internal leak is determined based on the correspondence between the pressure P2 and the reference pressure P2S. Can be determined. In this case, for example, it is confirmed whether or not the pressure P2 is within a predetermined range (P2S-Z≤P2≤P2S + Z) with respect to the reference pressure P2S (step S36). Since the value of Z is not particularly limited, it can be arbitrarily set after taking into consideration factors such as a measurement error of the pressure P2. Here, the value of Z is, for example, a value corresponding to 3% of the reference pressure P2S.

  When the pressure P2 is not within the predetermined range with respect to the reference pressure P2S (step S36N), the pressure P2 is significantly different from the reference pressure P2S even when the allowable margin (Z) is taken into consideration, so that internal leakage occurs. (Step S34).

  On the other hand, when the pressure P2 is within the predetermined range with respect to the reference pressure P2S (step S36Y), the pressure P2 is substantially equal to the reference pressure P2S in consideration of the allowable margin (Z). It is determined that no leak has occurred (step S37).

  Thus, the presence or absence of the internal leak is determined based on the pressure ratio R and the pressures P1 and P2, and the procedure for determining the internal leak is completed.

  In this case, for the reason described below, a higher effect can be obtained as compared with the case of determining the presence or absence of the internal leak based on only the pressure ratio R. That is, in the case of determining the presence or absence of the internal leak based on only the pressure ratio R, the pressure ratio R is changed even if both the pressures P1 and P2 are greatly changed due to the occurrence of the internal leak. Otherwise, it may be determined that the internal leak has not occurred. Specifically, for example, even if the pressure P1 is reduced due to the occurrence of the internal leak, the pressure P2 is similarly reduced due to the occurrence of the internal leak. As a result, the pressure ratio R It is possible that there is no fluctuation. However, if the presence / absence of the internal leak is determined not only based on the pressure ratio R but also based on both the pressures P1 and P2, the pressure ratio R does not change. Also, if one or both of the pressures P1 and P2 fluctuate, it is determined that an internal leak has occurred. Therefore, the presence or absence of the internal leak can be determined more accurately, and a higher effect can be obtained.

  In particular, the reference pressure P1S is acquired in advance using the normal inkjet head 100 in which no internal leak occurs, the pressure P1 is compared with the reference pressure P1S, and the pressure P1 is set to a predetermined value with respect to the reference pressure P1S. If it is determined that the internal leak has occurred when the pressure P1 is not within the range, the pressure P1 is compared with the pressure P1 at the normal time (reference pressure P1S), so that the pressure P1 exceeds a certain range from the reference pressure P1S. When it deviates to some extent, it is determined that an internal leak has occurred. Therefore, by performing the simple operation of comparing the pressure ratio P1 with the reference pressure P1S, the presence or absence of the internal leak can be determined with higher accuracy while suppressing the influence of measurement error and the like, and thus a higher effect can be obtained. You can

  The operation and effect described here are obtained by previously acquiring the reference pressure P2S using the normal inkjet head 100 in which no internal leak occurs, comparing the pressure P2 with the reference pressure P2S, and using the pressure P2 as the reference. Even if it is determined that the internal leak is occurring when the pressure P2S is not within the predetermined range, the same result is obtained.

  In addition, if the correlation CP1 is acquired in advance using the normal inkjet head 100 in which no internal leak occurs, and the pressure P1 corresponding to the flow rate M is set as the reference pressure P1S based on the correlation CP1. Even if the value of the flow rate M is changed, the normal pressure P1 (reference pressure P1S) corresponding to the changed flow rate M is specified based on the correlation P1. As a result, the reference pressure P1S serving as a reference for determining the presence or absence of the internal leak is accurately determined without depending on the value of the flow rate M. Therefore, even if the flow rate M is changed, the presence / absence of an internal leak can be determined with high accuracy, and a higher effect can be obtained.

  The operations and effects described here are obtained by previously acquiring the correlation CP2 using the normal inkjet head 100 in which no internal leak occurs, and based on the correlation CP2, the pressure P2 corresponding to the flow rate M is used as a reference. The same is obtained when the pressure is set to P2S.

  Of course, when the presence / absence of an internal leak is determined based on the pressure P1, the number of determinations is only once, as in the case of determining the presence / absence of an internal leak based on the pressure ratio R described above. The number is not limited, and may be two or more times. Further, in the case of determining the presence or absence of the internal leak based on the pressure P2, the number of times the determination is performed is only once, as in the case of determining the presence or absence of the internal leak based on the pressure ratio R described above. The number is not limited, and may be two or more times. If the number of judgments is increased, the accuracy of the judgment is further improved, so that a higher effect can be obtained.

[Modification 4]
In FIG. 8, the presence / absence of the internal leak is determined based on both of the pressures P1 and P2. However, as shown in FIG. 9 corresponding to FIG. 8, the internal leak is determined based on either of the pressures P1 and P2. The presence or absence of may be determined.

  Specifically, after performing the preparatory procedure (FIG. 3) and the internal leak determination procedure (FIG. 4) based on the pressure ratio R, first, the reference pressure P1S is acquired (step S41). Then, the presence or absence of the internal leak is determined based on the pressure P1, and specifically, for example, the pressure P1 is compared with the reference pressure P1S (step S42). In this case, for example, it is confirmed whether or not the pressure P1 is within a predetermined range with respect to the reference pressure P1S (step S43).

  When the pressure P1 is not within the predetermined range with respect to the reference pressure P1S (step S43N), it is determined that an internal leak has occurred (step S44), and the pressure P1 is within the predetermined range with respect to the reference pressure P1S. If it is within the range (step S43Y), it is determined that the internal leak has not occurred (step S45).

  Thus, the presence or absence of the internal leak is determined based on the pressure P and the pressure P1, and the procedure for determining the internal leak is completed. Of course, here, the case where the presence or absence of the internal leak is determined based on the pressure P and the pressure P1 has been described, but the presence or absence of the internal leak may be determined based on the pressure P and the pressure P2.

  Even in this case, even if the pressure ratio R does not change, if the pressure P1 or the pressure P2 changes, it is determined that an internal leak has occurred, and therefore the same effect can be obtained. The other actions and effects are similar to those in the case where the presence or absence of the internal leak is determined based on both the pressures P1 and P2.

[Modification 5]
Although gas is used as the fluid F, a liquid such as the ink 1 may be used as the fluid F. In this case as well, it is possible to easily and accurately determine whether or not an internal leak has occurred in the inkjet head 100 (flow path L), and therefore the same effect can be obtained. However, as described above, it is preferable to use gas as the fluid F in order to avoid the need for a cleaning process or the like due to the adhesion of the ink 1.

[Modification 6]
When the pressure ratio R is calculated, the denominator is the pressure P1 and the numerator is the pressure P2 (R = P2 / P1). However, for example, the denominator may be the pressure P2 and the numerator is the pressure P1 (R = P2). P1 / P2). Further, in the case of determining the presence or absence of the internal leak based on both the pressures P1 and P2, the presence or absence of the internal leak is determined based on the pressure P1, and then the presence or absence of the internal leak is determined based on the pressure P2. Alternatively, the presence or absence of the internal leak may be determined based on the pressure P2, and then the presence or absence of the internal leak may be determined based on the pressure P1. Even in these cases, the same effect can be obtained.

[Modification 7]
After calculating the pressure ratio R, the pressure ratio R was compared with the reference pressure ratio RS in order to determine the presence / absence of internal leak. However, the presence / absence of internal leak was determined based on only the pressure ratio R without using the reference pressure ratio RS. May be determined.

  In this case, for example, the pressure ratio R is calculated for each inkjet head 100 by measuring the pressures P1 and P2 using a plurality of inkjet heads 100, and then the pressure ratio R of each inkjet head 100 is compared. Accordingly, for example, when the pressure ratio R of each inkjet head 100 is within a predetermined range, it is determined that no internal leak has occurred in each inkjet head 100. On the other hand, for example, when the pressure ratio R of some of the inkjet heads 100 is outside the predetermined range, while the pressure ratio R of the other inkjet heads 100 is within the predetermined range, part of it It is determined that the internal leak has occurred in the inkjet head 100.

  In this case as well, the same effect can be obtained because whether or not an internal leak has occurred in the inkjet head 100 (flow path L) is easily and accurately determined based on the pressure ratio R.

[Modification 8]
Although the case where the inkjet head 100 is the side shoot type has been described, for example, the inkjet head 100 may be the edge shoot type. The edge chute type inkjet head 100 is different from the side chute type inkjet head 100 in which the ink 1 is ejected in the direction intersecting the extending direction of the plurality of channels, and in the same direction as the extending direction of the plurality of channels. Ink 1 is ejected. Even in this case, the same effect can be obtained.

  Although the present disclosure has been described above with reference to the embodiment, the aspects of the present disclosure are not limited to the aspects described in the above-described embodiment. Therefore, various modifications can be made to the aspects of the present disclosure.

  Specifically, the application of the liquid ejecting head is not particularly limited as long as it is an application that requires ejecting a liquid onto an object as described above. Therefore, the application of the liquid ejecting head is not limited to the printer (inkjet printer) described above, and may be a facsimile, an on-demand printing machine, or the like.

  It should be noted that the effects described in this specification are merely examples and are not limited, and may have other effects.

Further, the present disclosure can also take the following configurations.
(1)
A flow passage through which a fluid flows from the first flow passage opening toward the second flow passage opening, and one of the fluids that are provided in the flow passage between the first flow passage opening and the second flow passage opening and flow through the flow passage. Using a liquid jet head having a discharge port for discharging the portion to the outside,
By opening the first flow path opening and closing the second flow path opening, the fluid is caused to flow from the first flow path opening to the flow path at a predetermined flow rate, so that the first flow path opening to the discharge opening is performed. Measuring a first pressure, which is the pressure of the fluid flowing toward it,
The first flow path port is closed and the second flow path port is opened, and the fluid is flowed from the second flow path port to the flow path at the predetermined flow rate, whereby the second flow path port releases the discharge port. Measuring a second pressure, which is the pressure of the fluid flowing toward
Calculating a pressure ratio based on the first pressure and the second pressure,
On the basis of the pressure ratio, the presence or absence of leakage of the fluid flowing through the flow path from the first flow path opening to the second flow path opening is determined.
Liquid jet head inspection method.
(2)
A reference pressure ratio, which is the pressure ratio calculated based on the first pressure and the second pressure using the liquid jet head in which the fluid does not leak, is acquired in advance,
Comparing the pressure ratio with the reference pressure ratio when determining the presence or absence of fluid leakage,
When the pressure ratio is not within a predetermined range with respect to the reference pressure ratio, it is determined that the fluid has leaked.
The liquid jet head inspection method according to (1) above.
(3)
The correlation between the flow rate and the pressure ratio is obtained in advance by using the liquid ejecting head in which the fluid does not leak,
When acquiring the reference pressure ratio, based on the correlation between the flow rate and the pressure ratio, the pressure ratio corresponding to the predetermined flow rate is the reference pressure ratio,
The liquid jet head inspection method according to (2) above.
(4)
Furthermore, the presence or absence of leakage of the fluid is determined based on at least one of the first pressure and the second pressure.
The method for inspecting a liquid jet head according to any one of (1) to (3) above.
(5)
A first reference pressure, which is the first pressure measured using the liquid jet head in which the fluid does not leak, is acquired in advance,
Comparing the first pressure with the first reference pressure when determining the presence or absence of fluid leakage;
When the first pressure is not within a predetermined range with respect to the first reference pressure, it is determined that the fluid is leaking,
A second reference pressure, which is the second pressure measured using the liquid jet head in which the fluid does not leak, is acquired in advance,
Comparing the second pressure with the second reference pressure when determining the presence or absence of leakage of the liquid,
When the second pressure is not within a predetermined range with respect to the second reference pressure, it is determined that the fluid is leaking.
The liquid jet head inspection method according to (4) above.
(6)
The correlation between the flow rate and the first pressure is acquired in advance by using the liquid ejecting head in which the fluid does not leak,
When acquiring the first reference pressure, based on the correlation between the flow rate and the first pressure, the first pressure corresponding to the predetermined flow rate as the first reference pressure,
A correlation between the flow rate and the second pressure is acquired in advance using the liquid ejecting head in which the fluid does not leak,
When obtaining the second reference pressure, the second pressure corresponding to the predetermined flow rate is set as the second reference pressure based on the correlation between the flow rate and the second pressure.
The liquid jet head inspection method according to (5) above.
(7)
Using gas as the fluid,
The method for inspecting a liquid jet head according to any one of (1) to (6) above.

  1 ... Ink, 11H ... Nozzle hole, 40T ... Inlet port, 50T ... Ejection port, 100 ... Inkjet head, F ... Fluid, L (L1 to L3) ... Flow path, P1, P2 ... Pressure, P1S, P2S ... Reference pressure , R ... pressure ratio, RS ... reference pressure ratio.

Claims (7)

A flow passage through which a fluid flows from the first flow passage opening to the second flow passage opening, and one of the fluids that are provided in the flow passage between the first flow passage opening and the second flow passage opening and flow through the flow passage. Using a liquid jet head having a discharge port for discharging the portion to the outside,
By opening the first flow path opening and closing the second flow path opening, the fluid is caused to flow from the first flow path opening to the flow path at a predetermined flow rate, so that the first flow path opening to the discharge opening is performed. Measuring a first pressure, which is the pressure of the fluid flowing toward it,
The first flow path port is closed and the second flow path port is opened, and the fluid is flowed from the second flow path port to the flow path at the predetermined flow rate, whereby the second flow path port releases the discharge port. Measuring a second pressure, which is the pressure of the fluid flowing toward
Calculating a pressure ratio based on the first pressure and the second pressure,
On the basis of the pressure ratio, the presence or absence of leakage of the fluid flowing through the flow path from the first flow path opening to the second flow path opening is determined.
Liquid jet head inspection method. A reference pressure ratio, which is the pressure ratio calculated based on the first pressure and the second pressure using the liquid ejecting head in which the fluid does not leak, is acquired in advance,
Comparing the pressure ratio with the reference pressure ratio when determining the presence or absence of fluid leakage,
When the pressure ratio is not within a predetermined range with respect to the reference pressure ratio, it is determined that the fluid has leaked.
The method for inspecting a liquid jet head according to claim 1. The correlation between the flow rate and the pressure ratio is obtained in advance by using the liquid ejecting head in which the fluid does not leak,
When acquiring the reference pressure ratio, based on the correlation between the flow rate and the pressure ratio, the pressure ratio corresponding to the predetermined flow rate is the reference pressure ratio,
The method for inspecting a liquid jet head according to claim 2. Furthermore, the presence or absence of leakage of the fluid is determined based on at least one of the first pressure and the second pressure.
A method for inspecting a liquid ejecting head according to claim 1. A first reference pressure, which is the first pressure measured using the liquid jet head in which the fluid does not leak, is acquired in advance,
Comparing the first pressure with the first reference pressure when determining the presence or absence of fluid leakage;
When the first pressure is not within a predetermined range with respect to the first reference pressure, it is determined that the fluid is leaking,
A second reference pressure, which is the second pressure measured using the liquid jet head in which the fluid does not leak, is acquired in advance,
Comparing the second pressure with the second reference pressure when determining the presence or absence of leakage of the liquid,
When the second pressure is not within a predetermined range with respect to the second reference pressure, it is determined that the fluid is leaking.
The liquid jet head inspection method according to claim 4. The correlation between the flow rate and the first pressure is acquired in advance by using the liquid ejecting head in which the fluid does not leak,
When acquiring the first reference pressure, based on the correlation between the flow rate and the first pressure, the first pressure corresponding to the predetermined flow rate as the first reference pressure,
A correlation between the flow rate and the second pressure is acquired in advance using the liquid ejecting head in which the fluid does not leak,
When obtaining the second reference pressure, the second pressure corresponding to the predetermined flow rate is set as the second reference pressure based on the correlation between the flow rate and the second pressure.
The method for inspecting a liquid jet head according to claim 5. Using gas as the fluid,
The method for inspecting a liquid ejecting head according to claim 1.

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