JP2012223894A - Liquid ejection device, nozzle inspection method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain useless consumption of liquid in nozzle inspection.SOLUTION: A noise inspection is carried out prior to a nozzle inspection that includes an ejection inspection which is an inspection of ink ejection from a nozzle to be inspected (S140). When determining that there is noise, the noise inspection is repeated until determining that there is no noise or until the noise inspection frequency S reaches a threshold Sref or more (S150, 250, 260). When determining that there is no noise, meanwhile, a nozzle inspection including the ejection inspection is carried out (S150-180). The start of the nozzle inspection including the ejection inspection in a state of determining that there is noise can thereby be prevented. As a result, the execution of a useless ejection inspection is restrained, and the useless consumption of liquid in the nozzle inspection can be restrained.

Description

  The present invention relates to a liquid ejection apparatus, a nozzle inspection method, and a program.

  2. Description of the Related Art Conventionally, as a liquid ejection apparatus, a first electrode that sets a liquid discharged from a plurality of nozzles formed on a head to a first potential and a second electrode that is a second potential different from the first potential. Whether or not the liquid was normally ejected from each nozzle based on the electrical change between the two electrodes when the liquid was sequentially ejected from the plurality of nozzles toward the second electrode with the voltage applied to the What to do is known. The process for determining whether or not the liquid has been ejected from the nozzle in this way is referred to as nozzle inspection or ejection inspection.

  For example, in the liquid ejection device disclosed in Patent Document 1, 15 nozzles are used as one block, and the nozzle ejection inspection is performed for each block as a head ejection test in which more than 1000 nozzles are formed on a nozzle plate. In addition, one noise inspection period (also referred to as a non-ejection dummy period) is provided every time one block of discharge inspection is performed, and whether noise is mixed during discharge inspection depending on whether noise is generated during this period. Check for no. That is, if noise does not occur during the noise inspection period, the ejection inspection of the block immediately before is validated, and if noise occurs, the ejection inspection of the block immediately before is invalidated. As a result, even if it is a nozzle that cannot actually discharge liquid, even if it is erroneously determined that liquid was discharged due to noise mixed during discharge inspection, the erroneous determination is invalidated by performing noise inspection. be able to.

JP 2010-64309 A

  However, since 15 nozzles are used as one block, when noise is generated during the noise inspection period, all the 15 nozzle ejection inspections performed in the immediately preceding block are invalid. In this case, the liquid discharged from the 15 nozzles for the discharge inspection is consumed wastefully.

  The liquid ejection apparatus, the nozzle inspection method, and the program of the present invention are mainly intended to suppress wasteful liquid consumption in the nozzle inspection.

  The liquid ejection apparatus, the nozzle inspection method, and the program according to the present invention employ the following means in order to achieve the main object described above.

The liquid ejection device of the present invention is
A liquid ejection device that ejects liquid from a plurality of nozzles,
A first electrode in contact with the liquid;
A second electrode provided at a position capable of facing the first electrode;
Liquid was ejected from one of the plurality of nozzles to be inspected toward the second electrode in a state where a voltage was applied between the first electrode and the second electrode facing each other. Sometimes a discharge inspection for inspecting the presence or absence of liquid discharge from the nozzle to be inspected based on a potential change in at least one of the electrodes, and the potential change when liquid is not discharged from all of the plurality of nozzles. An inspection means for inspecting the presence or absence of noise based on each nozzle,
With
The inspection means performs the noise inspection prior to the ejection inspection, and repeats the noise inspection until noise disappears when there is noise in the noise inspection, and performs the ejection inspection when there is no noise in the noise inspection. It is summarized as a means.

  In the liquid ejection apparatus according to the present invention, the first electrode and the second electrode are opposed to each other and a voltage is applied between the two electrodes, and the nozzle to be inspected is directed from one of the plurality of nozzles to the second electrode. Discharge inspection for inspecting the presence or absence of liquid discharge from the nozzle to be inspected based on the potential change of at least one of the electrodes when liquid is discharged, and the potential change when liquid is not discharged from all of the plurality of nozzles A noise inspection for inspecting the presence or absence of noise is performed for each nozzle. In addition, a noise inspection is performed prior to the discharge inspection. If there is noise in the noise inspection, the noise inspection is repeated until the noise disappears, and if there is no noise in the noise inspection, the discharge inspection is performed. Thereby, since it is possible to prevent the discharge inspection from being started in a state where there is noise, it is possible to suppress the wasteful discharge inspection from being performed, and it is possible to suppress the wasteful liquid consumption in the nozzle inspection.

  In such a liquid ejection apparatus of the present invention, the inspection means may be means for limiting the repetition of the noise inspection to a predetermined number of times even when there is noise in the noise inspection. In this way, it is possible to prevent the noise inspection from being repeated indefinitely when noise is not lost.

  In the liquid ejection apparatus of the present invention, the inspection unit performs the inspection by performing the ejection inspection and the noise inspection subsequent to the ejection inspection when there is no noise in the previous noise inspection prior to the ejection inspection. The target nozzle is inspected, and when there is noise in the subsequent noise inspection, the noise inspection is repeated until the noise disappears, and when the noise disappears, the nozzle to be inspected immediately before is reinspected, and the subsequent noise inspection is performed. In the case where there is no noise, the above noise inspection may be omitted to inspect the next inspection target nozzle. By doing so, it is possible to combine the noise inspection with the determination as to whether or not the next discharge inspection can be started without noise and the determination as to whether or not the previous discharge inspection is affected by noise. In this aspect of the liquid ejection apparatus of the present invention, the inspection means is a means for performing the previous noise inspection every time without any noise even when there is no noise in the subsequent noise inspection. You can also. In this way, the noise inspection for determining whether or not the next ejection inspection can be started without noise can be dedicated. For this reason, it is possible to more accurately determine whether or not the discharge inspection can be started in the absence of noise.

  Further, in the liquid ejection apparatus according to the present invention, the inspection unit inspects the nozzle to be inspected by performing the ejection inspection when there is no noise in the previous noise inspection prior to the ejection inspection, and the previous noise When there is noise in the inspection, the noise inspection is repeated until the noise disappears, and when the noise disappears, the nozzle to be inspected immediately before by the discharge inspection is re-inspected, and when there is no noise in the previous noise inspection, It can also be a means for inspecting the nozzle to be inspected. By doing so, it is possible to combine the noise inspection with the determination as to whether or not the next discharge inspection can be started without noise and the determination as to whether or not the previous discharge inspection is affected by noise. In addition, since this noise inspection is not subsequent to the discharge inspection, for example, if the noise inspection is performed immediately before the next discharge inspection, it is determined whether or not the discharge inspection can be started without noise. This can be done with higher accuracy.

The nozzle inspection method of the present invention includes:
A nozzle inspection method for a liquid ejection device comprising: a first electrode that ejects liquid from a plurality of nozzles; and a second electrode that is provided at a position that can face the first electrode;
Liquid was ejected from one of the plurality of nozzles to be inspected toward the second electrode in a state where a voltage was applied between the first electrode and the second electrode facing each other. Sometimes a discharge inspection for inspecting whether or not liquid is discharged from the nozzle based on a potential change of at least one of the electrodes, and noise based on the potential change when the liquid is not discharged from all of the plurality of nozzles In performing the noise inspection for inspecting the presence or absence of each nozzle, the noise inspection is performed prior to the ejection inspection, and when there is noise in the noise inspection, the noise inspection is repeated until the noise disappears, and the noise inspection is performed. The discharge inspection is performed when there is no noise.

  According to the nozzle inspection method of the present invention, the first electrode and the second electrode are made to face each other and a voltage is applied between both electrodes, and the nozzle to be inspected from one of the plurality of nozzles to the second electrode. When the liquid is discharged in the direction of the discharge, the discharge inspection for inspecting the presence or absence of liquid discharge from the nozzle to be inspected based on the potential change of at least one of the electrodes, and when the liquid is not discharged from all of the plurality of nozzles A noise inspection for inspecting the presence or absence of noise based on the potential change is performed for each nozzle. In addition, a noise inspection is performed prior to the discharge inspection. If there is noise in the noise inspection, the noise inspection is repeated until the noise disappears, and if there is no noise in the noise inspection, the discharge inspection is performed. Thereby, since it is possible to prevent the discharge inspection from being started in a state where there is noise, it is possible to suppress the wasteful discharge inspection from being performed, and it is possible to suppress the wasteful liquid consumption in the nozzle inspection. In this nozzle inspection method, steps for realizing each function of the liquid ejection device described above may be added.

  The program of this invention is for making a computer implement | achieve each step of the nozzle inspection method mentioned above. This program may be recorded on a computer-readable recording medium (for example, hard disk, ROM, FD, CD, DVD, etc.) or from a computer via a transmission medium (communication network such as the Internet or LAN). It may be distributed to another computer, or may be exchanged in any other form. If this program is executed by a computer, each step of the above-described nozzle inspection method of the present invention is realized, so that the same effect as the nozzle inspection method of the present invention can be obtained.

1 is a block diagram illustrating a configuration of an inkjet printer 10. FIG. FIG. 2 is a schematic cross-sectional view of the printer 10. FIG. 2 is a schematic plan view of the printer 10. FIG. 3 is an explanatory diagram showing an arrangement of a plurality of heads 62 in the head unit 60. Explanatory drawing which shows arrangement | positioning of the several nozzle formed in the 1st head 62a. Explanatory drawing which shows the mode of printing. An explanatory view showing the whole composition of inspection unit 70. FIG. The top view of the test | inspection electrode 72. FIG. Explanatory drawing which shows the drive signal COM and the detection signal corresponding to it. Explanatory drawing which shows an example of a test signal in a detection signal and a detection control part. The flowchart which shows an example of a nozzle test | inspection routine. Explanatory drawing which shows an example of the content of a nozzle test | inspection, a digital signal, and a test result. Explanatory drawing which shows the mode of a nozzle test | inspection. The flowchart which shows the nozzle test | inspection routine of a modification. Explanatory drawing which shows the mode of the nozzle test | inspection of a modification. The flowchart which shows the nozzle test | inspection routine of a modification. Explanatory drawing which shows the mode of the nozzle test | inspection of a modification.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of an ink jet type printer 10, FIG. 2 is a schematic cross-sectional view of the printer 10, and FIG. 3 is a schematic plan view of the printer 10.

  The printer 10 is communicably connected to a personal computer (PC) 100, receives print data from the PC 100, and prints an image on a print medium S such as paper or cloth based on the print data. The printer 10 includes a controller 20 that executes various controls and outputs commands, and a unit group 30 that executes various processes while exchanging signals with the controller 20.

  The controller 20 includes a CPU 22 that controls the entire printer 10 and a unit control circuit 24 that controls each unit of the unit group 30. The CPU 22 executes various programs stored in the memory 28 based on detection signals input from various detectors provided in the unit group 30 and print data received from the PC 100 via the interface unit (I / F) 26. Then, each unit is controlled via the unit control circuit 24 while temporarily storing data in the memory 28. The unit group 30 includes a transport unit 40 that transports the print medium S, a moving unit 50 that moves the head unit 60, a head unit 60 that drives the head 62 so as to eject ink from the nozzles, and nozzles formed on the head 62. An inspection unit 70 that performs inspection is included. 2 and 3, the transport unit 40 transports the roll-shaped print medium S from the upstream side in the transport direction (X direction) to the downstream side by the motor-driven upstream roller 42 and the downstream roller 44. Then, it is wound up by the winding mechanism 46. The print medium S is vacuum-sucked from the lower side of the platen 48 in the printing area between the rollers 42 and 44. Thereby, the position of the printing medium S during printing is fixed. 2 and 3, the moving unit 50 freely moves the head unit 60 in the transport direction (X direction) of the print medium S and the width direction (Y direction) of the print medium S. The moving unit 50 moves the head unit 60 in the X direction by the X-axis stage 52, and moves the head unit 60 together with the X-axis stage 52 in the Y direction by the Y-axis stage 54. As shown in FIG. 3, the head unit 60 includes a head 62 having a plurality of nozzles, and ejects ink from the nozzles toward the print medium S by a drive signal from the controller 20. The head unit 60 includes a plurality of heads 62 as will be described later. Each head 62 ejects ink by pressure using a piezo element. The inspection unit 70 is for inspecting whether or not the nozzle is clogged. As shown in FIG. 3, the inspection unit 70 includes an inspection electrode 72 at a position that can face the head 62 of the head unit 60. Details of the inspection unit 70 will be described later.

  The head unit 60 will be described in more detail. FIG. 4 is an explanatory diagram showing the arrangement of the plurality of heads 62 in the head unit 60. In the drawing, the arrangement of the head 62 is shown as seen through the top surface of the printer 10. As shown in FIG. 4, the head unit 60 has 15 heads 62. The fifteen heads 62 are arranged in a zigzag along the Y direction. For convenience of explanation, the first head 62a, the second head 62b,..., The fourteenth head 62n, and the fifteenth head 62o are referred to from the upper end side to the lower end side in the Y direction. For this reason, the odd-numbered heads 62a, 62c, 62e... Form a straight line so as to be parallel to the Y direction, and the even-numbered heads 62b, 62d, 62f. Make a straight line so that

  FIG. 5 is an explanatory diagram showing the arrangement of a plurality of nozzles formed in the first head 62a. In the drawing, the nozzle arrangement is shown as seen through the top surface of the first head 62a. Further, the second head 62b to the fifteenth head 62o have the same configuration as the first head 62a. The first head 62a has a nozzle row of eight colors. Specifically, in order from the left side of FIG. 5, the Mk row for ejecting mat black ink, the Gr row for ejecting green ink, the Or row for ejecting orange ink, the Cl row for ejecting clear ink, and the photo black ink are ejected. Pk column, Cy column that discharges cyan ink, Ma column that discharges magenta ink, and Ye column that discharges yellow ink. Each nozzle row has 180 nozzles. The 180 nozzles are arranged at a constant nozzle pitch (1/180 inch) along the Y direction. For convenience of explanation, they are referred to as # 1, # 2,..., # 180 in order from the nozzle on the upper end side in the Y direction. Looking at each nozzle row of the first head 62b and each nozzle row of the second head 62b, the Y coordinate position of each of the four nozzles on the lower end side in the Y direction of the first head 62a is Y of the second head 62b. The Y coordinate positions of the four nozzles on the upper end side in the direction coincide with each other. Thus, two nozzles having the same Y coordinate position can form dots while interpolating each other. This relationship is the same between the α-th head and the (α + 1) -th head (α is an integer from 1 to 14).

  The procedure for printing on the print medium S using such a head unit 60 will be outlined below. 2 and 3, the controller 20 controls the transport unit 40 so that a new surface of the print medium S is supplied to the print area, and also controls the moving unit 50 so that the head unit 60 is at the initial position. . The initial position is the most upstream position in the X direction and the most extreme position in the Y direction in the print area. The head unit 60 disposed at the initial position is indicated by a solid line in FIGS. At the same time, the controller 20 controls the moving unit 50 so that the head unit 60 moves from the most upstream position in the X direction of the printing region to the most downstream position (indicated by a one-dot chain line in FIGS. 2 and 3). By controlling the head unit 60 so as to eject ink from the nozzles of the moving head 62, dot rows arranged in the X direction are formed. This operation is referred to as one pass. After forming a dot row for one pass in this way, the controller 20 controls the moving unit 50 so that the head unit 60 moves to the lower end side in the Y direction, and executes the next one pass again to execute the dot row in the X direction. Form. An example of the head unit 60 moved to the lower end side in the Y direction is indicated by a two-dot chain line in FIG. Then, when the operation of the number of passes determined according to the width direction of the print medium S is completed, the image of the print area of the print medium S is completed. FIG. 6 is an explanatory diagram showing a state of printing. FIG. 6 illustrates a nozzle row in which five nozzles are arranged in a row parallel to the Y direction for convenience of explanation. FIG. 6 shows a state in which dot rows in the X direction for a total of four passes from pass 1 to pass 4 are sequentially formed.

  The inspection unit 70 will be described in detail below. FIG. 7 is an explanatory diagram showing the overall configuration of the inspection unit 70. The inspection unit 70 includes a metal plate-like inspection electrode 72 that receives ink ejected from nozzles formed on the head 62, and a high-voltage power source 74 that applies a voltage between the inspection electrode 72 and the nozzle plate 63 of the head 62. And a detection control unit 76 that determines the magnitude of the signal based on a voltage signal when ink is ejected from the nozzle in a state where a voltage is applied between the inspection electrode 72 and the nozzle plate 63. The nozzle plate 63 is a plate on which a plurality of nozzles are formed, and also functions as a part of the inspection unit 70.

  The inspection electrode 72 is basically formed at a rate of one for the two heads 62. FIG. 8 shows a plan view of the inspection electrode 72. In this embodiment, since the number of heads is 15, eight inspection electrodes 72 are formed correspondingly. For convenience of explanation, the eight inspection electrodes 72 are referred to as a first inspection electrode 72A, a second inspection electrode 72B,. Specifically, as shown in FIG. 8, the first inspection electrode 72A for the first head 62a and the third head 62c, the second inspection electrode 72B for the fifth head 62e and the seventh head 62g, and the ninth The third inspection electrode 72C for the head 62i and the eleventh head 62k, the fourth inspection electrode 72D for the thirteenth head 62m and the fifteenth head 62o, and the fifth inspection electrode for the second head 62b and the fourth head 62d. 72E, a sixth inspection electrode 72F for the sixth head 62f and the eighth head 62h, a seventh inspection electrode 72G for the tenth head 62j and the twelfth head 62l, and an eighth inspection electrode 72H for the fourteenth head 62n. Is formed. That is, in the present embodiment, since the number of heads 62 is 15, one inspection electrode 72 corresponds to one head 62 in the fourteenth head 62n. As shown in FIG. 3, such an inspection electrode 72 is provided at a position off the left side (upstream side in the X direction) from the printing region. FIG. 7 shows the configuration of the electric circuit for one inspection electrode 72, but such an electric circuit is assembled for each of the first to eighth inspection electrodes 72A to 72H.

  The high-voltage power source 74 is a power source for setting the inspection electrode 72 to a predetermined potential, and is constituted by a DC power source of 600 to 1000 V here. A first limiting resistor 73 and a second limiting resistor 75 are disposed between the high voltage power supply 74 and the inspection electrode 72. These limiting resistors 73 and 75 control the current flowing between the high-voltage power supply 74 and the inspection electrode 72, and here the resistance values of both are set to 1.6 MΩ.

  The detection control unit 76 controls voltage application between the inspection electrode 72 and the nozzle plate 63 by the high voltage power source 74. Further, the detection control unit 76 determines whether or not the inspection target nozzle ejects ink based on the voltage signal (analog signal) of the inspection electrode 72 amplified by the amplifier 77, and the controller 20 uses the determination result as a digital signal. Send to. Between the amplifier 77 and the inspection electrode 72, an inspection capacitor 78 for removing a bias component (DC component) of the inspection electrode 72 is disposed. One end of a smoothing capacitor 79 is connected between the first limiting resistor 73 and the second limiting resistor 75. The other end of the smoothing capacitor 79 is grounded. The smoothing capacitor 79 suppresses a rapid change in potential. Here, the capacity of the inspection capacitor 78 is 4700 pF, the amplification factor of the amplifier 77 is 4000 times, and the capacity of the smoothing capacitor 79 is 0.1 μF.

  Next, the operation of the printer 10 of this embodiment, particularly the operation when inspecting the nozzles will be described. The controller 20 performs a discharge inspection for checking whether ink can be discharged well from the nozzle to be inspected, and a noise inspection for checking whether noise affecting the determination result of the discharge inspection is generated. Inspect the nozzle.

  First, the discharge inspection will be described. FIG. 9 is an explanatory diagram showing the drive signal COM and the detection signal corresponding to the drive signal COM. FIG. 9A shows the waveform of the drive signal COM, and FIG. 9B shows the waveform of the detection signal output from the amplifier 77. The controller 20 outputs a drive signal COM for driving the piezo element shown in FIG. 9A to each head 62 with the voltage of the high voltage power supply 74 applied between the nozzle plate 63 and the inspection electrode 72. The drive signal COM is a combination of a pulse output section for outputting 20 to 30 ink ejection pulses and a pause section of a constant potential (intermediate potential). When such a drive signal COM is applied to a piezo element, 20 to 30 ink droplets are ejected from the nozzle corresponding to the piezo element. Then, in response to this, a detection signal (analog signal, see FIG. 9B) is output from the amplifier 77 to the detection control unit 76. The detection control unit 76 detects the amplitude Va of the detection signal corresponding to the drive signal COM (difference between the highest potential VH and the lowest potential VL of the detection signal), and detects the detected amplitude Va and a predetermined threshold Vth (for example, 3V). If the amplitude Va of the detection signal is larger than the threshold value Vth, the detection control unit 76 generates a digital signal indicating “large amplitude” (good ejection). Conversely, if the amplitude Va of the detection signal is smaller than the threshold value Vth, a digital signal representing “small amplitude” (ejection failure) is generated.

  Here, the principle of the discharge inspection will be described. In FIG. 7, when the head unit 60 is controlled to eject ink from the nozzle to be inspected in a state where a voltage is applied between the nozzle plate 63 and the inspection electrode 72, ink is actually ejected from the nozzle. In this case, the voltage signal of the inspection electrode 72 changes greatly, but when the ink is not ejected from the nozzle, the voltage signal of the inspection electrode 72 hardly changes. Therefore, it is possible to determine whether or not the inspection target nozzle has ejected ink based on the change in the voltage signal. Although this principle has not been clarified accurately, it is thought as follows. In general, it is known that when the distance between a pair of electrode plates constituting a capacitor changes, the charge stored in the capacitor changes. When ink is ejected from the ground potential nozzle plate 63 toward the high potential inspection electrode 72, the distance d (see FIG. 7) between the ink droplet of the ground potential and the inspection electrode 72 changes, and a pair of electrodes of the capacitor As when the distance between the plates changes, the charge stored in the inspection electrode 72 changes. As a result, the charge is transferred to the inspection electrode 72, and the inspection capacitor 78 and the amplifier 77 detect the voltage that changes accordingly, and the detection signal is output to the detection control unit 76.

  Next, noise inspection will be described. During the noise inspection period, the controller 20 does not give the drive signal COM to the piezo element of any nozzle in a state where the voltage of the high voltage power supply 74 is applied between the nozzle plate 63 and the inspection electrode 72. That is, the noise inspection period is a non-ejection period in which ink droplets are not ejected. Even during this period, the detection signal (analog signal) is output from the amplifier 77 to the detection control unit 76. The detection control unit 76 compares the amplitude Va of the detection signal with the threshold value Vth, and if the amplitude Va of the detection signal is larger than the threshold value Vth, a digital signal indicating “large amplitude” (with noise) is transmitted to the controller 20. To do. Conversely, if the amplitude Va of the detection signal is smaller than the threshold value Vth, a digital signal representing “small amplitude” (no noise) is transmitted to the controller 20. In FIG. 7, in the state where a voltage is applied between the nozzle plate 63 and the inspection electrode 72, when the drive signal COM is not applied to the piezo element of any nozzle, the voltage signal of the inspection electrode 72 is hardly changed. However, when noise occurs in the inspection electrode 72, the voltage signal of the inspection electrode 72 greatly changes due to the noise. For this reason, the presence or absence of noise can be determined based on the change in the voltage signal.

  Specific examples of discharge inspection and noise inspection will be described. Here, a case where the ejection inspection is performed twice for one nozzle and then the noise inspection is performed once will be described as an example. FIG. 10 shows an example of the detection signal output from the amplifier 77 at that time and the inspection result in the detection control unit 76. In FIG. 10A, since the amplitude Va of the detection signal exceeds the threshold value Vth in both ejection inspections, the detection control unit 76 generates both “large amplitude” digital signals, and in the subsequent noise inspection. Since the amplitude Va is equal to or less than the threshold value Vth, a “small amplitude” digital signal is generated. When these three digital signals are combined and determined, the nozzle is determined as “normal”. In FIG. 10B, since the amplitude Va of the detection signal is less than or equal to the threshold value Vth in the two ejection inspections, the detection control unit 76 generates both “small amplitude” digital signals, and the amplitude Va in the subsequent noise inspection. Is less than the threshold value Vth, a “small amplitude” digital signal is generated. When these three digital signals are integrated and determined, the nozzle is determined to be “abnormal”. In the detection signal of FIG. 10C, since the amplitude Va of the detection signal exceeds the threshold value Vth in the first ejection test, the detection control unit 76 generates a “large amplitude” digital signal, and in the second ejection test. Since the amplitude Va is equal to or smaller than the threshold value Vth, a “small amplitude” digital signal is generated. In the subsequent noise inspection, a digital signal having “small amplitude” is generated because the amplitude Va is equal to or smaller than the threshold value Vth. When these three digital signals are integrated and determined, the nozzle is determined to be “abnormal”. That is, if one of the plurality of ejection inspections is “small in amplitude” even once, the nozzle may be clogged, so that it is determined as “abnormal”. In FIG. 10D, since the amplitude Va of the detection signal exceeds the threshold value Vth in both of the ejection inspections, the detection control unit 76 generates both “large amplitude” digital signals, and also in the subsequent noise inspection. Since the amplitude Va exceeds the threshold value Vth, a “large amplitude” digital signal is generated. When these three digital signals are integrated and determined, the nozzle is determined as “unknown”. The fact that the amplitude Va exceeds the threshold value Vth in the noise inspection is highly likely that noise has been mixed in the previous ejection inspection, and the amplitude Va may have exceeded the threshold value Vth due to the noise. Whether it is normal or abnormal cannot be determined, and it is determined as “unknown”. In this way, when the noise test result is “large amplitude”, it is highly possible that the immediately preceding discharge test is affected by noise. Is determined. Note that one block, which is an inspection unit combining a plurality of ejection inspections for one nozzle and the subsequent noise inspection, is hereinafter referred to as a unit inspection block.

  Next, a nozzle inspection routine executed by the controller 20 will be described using the flowchart of FIG. The controller 20 starts this inspection routine every time the nozzle inspection execution timing comes. When this routine is started, the controller 20 first controls the moving unit 50 to move the head unit 60 so that each head 62 of the head unit 60 faces each inspection electrode 72 (step S100). Next, a value 1 is set to the variable p representing the nozzle row to be inspected (step S110), and the nozzle row of the p-th row is set as the inspection subject (step S120). Note that the Mk row, which is the leftmost nozzle row in FIG. 5, is the first row, the number of rows is counted up from the left to the right, and the Ye row, which is the rightmost nozzle row, is the eighth row. Subsequently, a value 1 is set to the variable q representing the number of the nozzle to be inspected (step S130), and only the noise inspection is individually executed prior to the ejection inspection (step S140), and the presence / absence of noise is determined (step S140). Step S150). This individual noise test is executed in the same manner as the noise test in the unit test block described above. When it is determined in step S150 that there is no noise, the noise inspection number S representing the number of times of performing only noise inspection separately from the unit inspection block is reset to 0 (step S160). The initial value of the noise inspection count S is 0, and the set of values will be described later. Next, the q-th (#q) nozzle of the p-th nozzle row to be inspected is set as the inspection target nozzle (step S170), and the nozzle inspection by the unit inspection block is executed for the inspection target nozzle (step S180). ). Specifically, the controller 20 continuously applies the drive signal COM shown in FIG. 9A to the piezo element of the q-th inspection target nozzle in the p-th nozzle row twice, and thereafter The drive signal COM is not given to the nozzle for a predetermined period. As a result, the nozzle inspection is performed by combining the two ejection inspections for the inspection target nozzle and the subsequent one noise inspection. The detection control unit 76 of the inspection unit 70 applies a detection signal of two ejection inspections and one noise inspection output from the amplifier 77 in a state where a voltage is applied between the inspection electrode 72 and the nozzle plate 63. And a digital signal generated from the acquired detection signal is output. At this time, the detection control unit 76 generates and outputs a digital signal indicating “large amplitude” if the amplitude Va of the acquired detection signal exceeds the threshold value Vth, and if the amplitude Va does not exceed the threshold value Vth, “ A digital signal representing “small amplitude” is generated and output.

  When the digital signal is output from the detection control unit 76 in this way, the controller 20 determines whether the inspection result is normal, abnormal, or unknown based on the output digital signal (step S190). This determination is performed as already described with reference to FIG. FIG. 12 shows an example of the contents of nozzle inspection, digital signals, and inspection results. FIG. 12A shows the contents of the nozzle inspection by the unit inspection block performed on the inspection target nozzle, FIG. 12B shows the digital signal output from the inspection control unit 76, and FIG. Indicates the test result. FIGS. 12B and 12C show the case where the inspection result is normal. When it is determined in step S190 that the inspection result is normal (see FIG. 10A) or abnormal (see FIGS. 10B and 10C), the result is registered in the memory 28 (step S200), and the inspection target It is determined whether or not the variable q representing the nozzle number has reached the upper limit value (here, value 180) (step S210). If the variable q has not reached the upper limit value, the variable q is incremented by one. (Step S220), the process returns to Step S170 and is repeated. As a result, when the inspection result for the nozzle to be inspected is registered, it is determined that there is no noise in the noise inspection in the unit inspection block, the individual noise inspection before the unit inspection block is omitted, and the next nozzle is inspected. The nozzle inspection by the unit inspection block is executed by setting the target. On the other hand, if the variable q has reached the upper limit value in step S210, it is determined whether or not the variable p representing the nozzle row to be inspected has reached the upper limit value (here, value 8) (step S230). If the value does not reach the upper limit value, the variable p is incremented by 1 (step S240), and the process returns to step S120 and is repeated. As a result, when the inspection results for all the nozzles in the nozzle row to be inspected are registered, the next nozzle row is set as the inspection subject and the nozzle inspection is executed. On the other hand, if the variable p has reached the upper limit value in step S230, this routine ends.

  On the other hand, if the test result is not normal or abnormal in step S190 and is unknown (see FIG. 10D), that is, if the test result cannot be determined due to the influence of noise, the process returns to step S140 and the noise test is performed. Execute. If it is determined that there is noise in step S150 as a result of the noise test that is performed when such a test result is unknown or the noise test that is performed after setting the value q to 1 in step S130 described above, The inspection number S is incremented by 1 (step S250), and it is determined whether or not the noise inspection number S is equal to or greater than the threshold value Sref (step S260). Here, the threshold value Sref is a value set as an upper limit value (for example, a value of 5) of the number of repetitions of the noise inspection in step S140. When the number of noise inspections S is not equal to or greater than the threshold value Sref, that is, when the number of noise inspections S has not reached the upper limit value of the number of repetitions, the process returns to step S140 to perform a noise inspection. If it is determined in step S150 that there is no noise due to the noise inspection, the number of noise inspections S is reset in step S160, and then the processes in and after step S170 are performed. As a result, while the number of noise inspections S is less than the threshold value Sref, only the noise inspection is repeatedly performed until it is determined that there is no noise, and the nozzle inspection is performed again when it is determined that there is no noise. When the inspection result is unknown in step S190 and the process returns to step S140 and the noise inspection is performed, the variable q is not incremented, so the previous inspection target nozzle becomes the inspection target nozzle again. That is, if the inspection result is unknown in step S190, it is confirmed that the noise has disappeared, and then the nozzle inspection is performed again on the same inspection target nozzle. On the other hand, when the number of noise inspections S is greater than or equal to the threshold value Sref in step S260, an error message is output informing that nozzle inspection cannot be completed due to the influence of noise (step S270), and this routine ends. As a result, it is possible to prevent the noise inspection from being repeated indefinitely when noise does not disappear. Note that the message may appeal visually or may appeal to hearing.

  Here, FIG. 13 shows a state of the nozzle inspection when the nozzle inspection routine is executed. FIG. 13A shows a state in which it is determined that there is no noise (OK) in individual noise inspection before nozzle inspection for nozzle # 1 and noise inspection in unit inspection blocks for nozzles # 1 to # 4. FIG. 13B shows a state where it is determined that there is noise (NG) in the noise inspection in the unit inspection block for the nozzle # 2. As shown in FIG. 13A, after the noise inspection in the unit inspection block determines that there is no noise, the nozzle inspection by the unit inspection block is executed for the next inspection target nozzle. Further, as shown in FIG. 13B, when it is determined that there is noise in the noise inspection in the unit inspection block for the nozzle # 2, the noise inspection is individually repeated. The nozzle inspection by the unit inspection block is re-executed with the nozzle of # 2 as the inspection object again. In this way, when it is determined that there is noise, the noise inspection is repeated until it is determined that there is no noise without starting the next nozzle inspection, and after it is determined that there is no noise, the nozzle inspection by the unit inspection block is performed. Since the nozzle inspection by the unit inspection block includes the ejection inspection, it is possible to prevent the ejection inspection from being started in a state where there is noise. As a result, it is possible to suppress the wasteful ejection inspection from being performed, and to suppress the wasteful consumption of ink in the nozzle inspection. Of course, the noise inspection in the unit inspection block is performed to determine whether or not the ejection inspection in the same unit inspection block is affected by noise. For this reason, when it is determined that there is noise in the noise inspection in the unit inspection block for the nozzle # 2, the nozzle inspection # 2 is re-executed assuming that the ejection inspection of the nozzle # 2 is affected by noise. As described above, in this embodiment, it is determined whether or not the next discharge inspection (nozzle inspection by the unit inspection block) can be started without noise, and whether or not the previous discharge inspection is affected by noise. The noise inspection in the unit inspection block can also be used for the determination. For this reason, the entire inspection time can be shortened as compared with a case where a dedicated noise inspection is used for each.

  Since the detection control unit 76 is attached to each of the first to eighth inspection electrodes 72A to 72H, the nozzle inspection of the first head 62a using the first inspection electrode 72A and the second inspection electrode 72B using the second inspection electrode 72B. Nozzle inspection of the 5th head 62e, Nozzle inspection of the 9th head 62i using the 3rd inspection electrode 72C, Nozzle inspection of the 13th head 62m using the 4th inspection electrode 72D, Nozzle of the 2nd head 62b using the 5th inspection electrode 72E The inspection, the nozzle inspection of the sixth head 62f using the sixth inspection electrode 72F, the nozzle inspection of the tenth head 62j using the seventh inspection electrode 72G, and the nozzle inspection of the fourteenth head 62n using the eighth inspection electrode 72H are performed in parallel. carry out. Further, the nozzle inspection of the third head 62c using the first inspection electrode 72A, the nozzle inspection of the seventh head 62g using the second inspection electrode 72B, the nozzle inspection of the eleventh head 62k using the third inspection electrode 72C, and the fourth inspection. Nozzle inspection of the fifteenth head 62o using the electrode 72D, nozzle inspection of the fourth head 62d using the fifth inspection electrode 72E, nozzle inspection of the eighth head 62h using the sixth inspection electrode 72F, and the seventh inspection electrode 72G using the seventh inspection electrode 72G. The nozzle inspection of 12 heads 62l is performed in parallel.

  By executing such a nozzle inspection routine, it is possible to grasp which nozzle is normal and which nozzle is abnormal among the plurality of nozzles of the first to fifteenth heads 62a to 62o. For this reason, the result can be used to perform cleaning on a head having an abnormal nozzle or to output a message recommending replacement of the head.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. The nozzle plate 63 of the present embodiment corresponds to the “first electrode” of the present invention, the inspection electrode 72 corresponds to the “second electrode”, and the processing of steps S140 to S150 and S180 of the nozzle inspection routine of FIG. 11 is executed. The controller 20 and the inspection unit 70 that perform the processing correspond to “inspection means”, and the controller 20 that executes the processes of steps S190 and S200 of the nozzle inspection routine in FIG. 11 corresponds to “determination means”. In the present embodiment, an example of the nozzle inspection method of the present invention is also clarified by describing the operation of the printer 10.

  According to the printer 10 of the present embodiment described above, the noise inspection is performed prior to the nozzle inspection by the unit inspection block including the discharge inspection, and when it is determined that there is noise, the noise inspection is repeated until it is determined that there is no noise. When it is determined that there is no noise, the nozzle inspection is performed by the unit inspection block including the ejection inspection, so that it is possible to prevent the ejection inspection from being started in the presence of noise, and wasteful liquid consumption in the nozzle inspection. Can be suppressed. Even when it is determined that there is noise by the noise inspection, the noise inspection is repeated until the noise inspection number S representing the number of repetitions of the noise inspection becomes the threshold value Sref. Therefore, the noise inspection is performed when the noise does not disappear. It is possible to prevent infinite repetition. Furthermore, the noise test in the unit test block is also used to determine whether or not the next discharge test can be started without noise and whether or not the previous discharge test was affected by noise. Can do.

  It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

  In the above-described embodiment, the individual noise inspection is omitted when there is no noise in the noise inspection in the unit inspection block. However, the present invention is not limited to this, and even when there is no noise in the noise inspection in the unit inspection block, A separate noise test may be performed every time before the nozzle test. FIG. 14 shows a modified nozzle inspection routine in this case, and FIG. 15 shows the state of nozzle inspection. In the nozzle inspection routine of FIG. 14, the same processes as those of the routine of FIG. In the nozzle inspection routine of this modification, when the q-th nozzle of the nozzle row to be inspected is set as the inspection target nozzle (step S170A), a noise inspection is performed in step S140, and after determining that there is no noise in step S150. In step S180, nozzle inspection is executed. That is, each time a nozzle to be inspected is set in step S170A, an individual noise inspection is executed every time, and after determining that there is no noise, a nozzle inspection is executed. For this reason, also in this modified example, since the nozzle inspection by the unit inspection block is not performed in the presence of noise, the discharge inspection is prevented from starting in the presence of noise, and ink is consumed wastefully. Can be suppressed. FIG. 15A shows a state in which no noise is determined in individual noise inspection before nozzle inspection for nozzles # 1 to # 3 and noise inspection in unit inspection blocks for nozzles # 1 to # 3. FIG. 15B shows a state in which it is determined that there is noise in the noise inspection in the unit inspection block for the nozzle # 2, and FIG. 15C shows the individual before the nozzle inspection for the nozzle # 3. A state when it is determined that there is noise in the noise inspection is shown. Individual noise inspections are repeated until it is determined that there is no noise in both FIGS. Further, in FIG. 15B, when it is determined that there is no noise by repeating the noise inspection, the nozzle inspection is re-executed with the nozzle # 2 that is the immediately preceding inspection target nozzle as the inspection target again. On the other hand, in FIG. 15C, unlike the case of FIG. 15B, it is determined that there is no noise in the noise inspection in the unit inspection block for the nozzle of # 2. It is unlikely that they were affected. Therefore, when it is determined that there is no noise by repeating the noise inspection, the nozzle inspection is performed with the nozzle # 3 next to the nozzle # 2 as the inspection target nozzle. Thereby, the individual noise test can be used exclusively for determining whether or not the next nozzle test (discharge test) can be started without noise. For this reason, it can be determined more accurately whether or not the discharge inspection can be started in a state without noise.

  In the embodiment described above, a plurality of ejection inspections and subsequent noise inspections are used as unit inspection blocks. However, the present invention is not limited to this, and at least one ejection inspection and subsequent noise inspections may be used as unit inspection blocks. Alternatively, the unit inspection block may not include the noise inspection, and at least one ejection inspection may be performed as the unit inspection block, and the noise inspection may be performed individually. FIG. 16 shows a modified nozzle inspection routine for the latter case, and FIG. 17 shows the state of the nozzle inspection. In the nozzle inspection routine of FIG. 16, the same processes as those of the routine of FIG. In the modified nozzle inspection routine, the inspection target nozzle is set in step S170, and then the ejection inspection is performed on the inspection target nozzle (step S175). This discharge inspection is performed in the same manner as the discharge inspection in the unit inspection block described above. When the ejection inspection is executed, a noise inspection is executed (step S185), and the presence or absence of noise is determined (step S195). When it is determined that there is no noise, the result of the ejection inspection is registered in the memory (step S205), and the processes after step S210 are performed. On the other hand, if it is determined in step S195 that there is noise, the processes in and after step S250 are performed. Further, when it is determined that there is noise in the noise inspection in step S140 or the noise inspection in step S185, the noise inspection in step S140 is repeatedly executed until the noise inspection frequency S becomes equal to or greater than the threshold value Sref in step S260, and the noise is determined in step S150. When it is determined that there is no nozzle, an inspection target nozzle is set in step S170, and then a discharge inspection is performed on the inspection target nozzle in step S175. For this reason, also in this modified example, it is possible to prevent the ejection inspection from being started in the presence of noise, and to suppress the wasteful consumption of ink. FIG. 17A shows a state in which no noise is determined in the noise inspection before nozzle inspection for nozzles # 1 to # 3, and FIG. 17B shows the individual after nozzle inspection for nozzle # 2. The situation when it is determined that there is noise in the noise test of is shown. As shown in FIG. 17A, since the nozzle inspection using the unit inspection block performs only the discharge inspection, the entire inspection time can be shortened as compared with the unit inspection block including the noise inspection. Even if the unit inspection block does not include a noise inspection, since the noise inspection is performed before the nozzle inspection to confirm that there is no noise, it is possible to prevent the inspection reliability from being impaired. Further, as shown in FIG. 17B, when it is determined that there is noise after performing the noise inspection after the nozzle inspection of the nozzle # 2, that is, before the nozzle inspection of the nozzle # 3, it is determined that there is no noise. Repeat the noise test until Then, after determining that there is no noise, the nozzle inspection is performed again with the nozzle # 2 that is the nozzle to be inspected immediately before as the inspection target. This is because the nozzle inspection (discharge inspection) of # 2 may have been affected by noise, and thus the inspection reliability is prevented from being impaired by re-inspecting the nozzle of # 2. In this way, it is possible to combine individual noise inspections for determining whether or not the next discharge inspection can be started without noise and for determining whether or not the previous discharge inspection is affected by noise. As a result, the entire inspection time can be shortened as compared with the case where each uses a dedicated noise inspection. In addition, since the individual noise inspection is independent of the unit inspection block, for example, if the inspection is performed immediately before the next nozzle inspection (discharge inspection), the discharge inspection can be started without noise. It can be determined with higher accuracy.

  In the above-described embodiment, two ejection inspections and one noise inspection are performed for each nozzle. If there is noise in the noise inspection, the result of the previous two ejection inspections is not adopted. However, even if there was noise in the noise test as described above, if both of the previous two discharge test results were “small amplitude”, there was almost no possibility that the noise was affected during the discharge test. Therefore, the result may be adopted and determined as “abnormal”.

  In the embodiment described above, the nozzle plate 63 is set to the ground potential and the test electrode 72 is set to the high potential, and the voltage change of the test electrode 72 is detected. However, the nozzle plate 63 is set to the high potential and the test electrode 72 is set to the ground potential. The change in voltage may be detected.

  In the embodiment described above, the inspection electrode 72 is provided on the flat surface beside the platen 48, but the inspection electrode 72 may be provided inside the cap of the head 62. Such a cap may be a moisturizing cap used for preventing the nozzle from drying, or may be a cleaning cap used for cleaning by sucking dust and ink in the nozzle.

  In the above-described embodiment, a method of ejecting ink by pressure using a piezo element is illustrated as an ink jet method. However, for example, a method of generating bubbles in a nozzle by heat may be employed.

  In the above-described embodiment, the example in which the fluid ejection device of the present invention is embodied in the ink jet printer 10 has been described. However, a liquid (dispersion) in which particles of a liquid other than ink or functional materials are dispersed, a gel The present invention may be embodied in a fluid ejection device that ejects a fluid or the like, or may be embodied in a fluid ejection device that ejects a solid that can be ejected as a fluid. For example, a liquid ejection device that ejects a liquid in which a material such as an electrode material or a color material used for manufacturing a liquid crystal display, an EL (electroluminescence) display, and a surface emitting display is ejected, or a liquid material in which the material is dispersed It is good also as a liquid discharge apparatus which discharges the liquid used as a liquid body discharge apparatus and a precision pipette as a sample. Also, transparent resin liquids such as UV curable resin to form liquid ejection devices that pinpoint lubricating oil to precision machines such as watches and cameras, micro hemispherical lenses (optical lenses) used for optical communication elements, etc. A liquid discharge device that discharges a liquid onto a substrate, a liquid discharge device that discharges an etching liquid such as acid or alkali to etch the substrate, a fluid discharge device that discharges gel, a powder that discharges powder such as toner A body discharge type recording apparatus may be used.

  10 printer, 20 controller, 22 CPU, 24 unit control circuit, 26 interface unit (I / F), 28 memory, 30 unit group, 40 transport unit, 42 upstream roller, 44 downstream roller, 46 take-up mechanism, 48 Platen, 50 moving unit, 52 X-axis stage, 54 Y-axis stage, 60 head unit, 62 head, 62a to 62o 1st to 15th head, 63 nozzle plate, 70 inspection unit, 72 inspection electrode, 72A to 72H 1st -8th test electrode, 73 1st limiting resistance, 74 high voltage power supply, 75 2nd limiting resistance, 76 detection control part, 77 amplifier, 78 testing capacitor, 79 smoothing capacitor, 100 personal computer (PC).

Claims (7)

A liquid ejection device that ejects liquid from a plurality of nozzles,
A first electrode in contact with the liquid;
A second electrode provided at a position capable of facing the first electrode;
Liquid was ejected from one of the plurality of nozzles to be inspected toward the second electrode in a state where a voltage was applied between the first electrode and the second electrode facing each other. Sometimes a discharge inspection for inspecting the presence or absence of liquid discharge from the nozzle to be inspected based on a potential change in at least one of the electrodes, and the potential change when liquid is not discharged from all of the plurality of nozzles. An inspection means for inspecting the presence or absence of noise based on each nozzle,
With
The inspection means performs the noise inspection prior to the ejection inspection, and repeats the noise inspection until noise disappears when there is noise in the noise inspection, and performs the ejection inspection when there is no noise in the noise inspection. A means for discharging liquid.   The liquid ejecting apparatus according to claim 1, wherein the inspection unit is a unit that limits the repetition of the noise inspection a predetermined number of times even when there is noise in the noise inspection.   The inspection means inspects the nozzle to be inspected by performing the discharge inspection and the noise inspection subsequent to the discharge inspection when there is no noise in the previous noise inspection prior to the discharge inspection, When there is noise in the noise inspection, the noise inspection is repeated until the noise disappears, and when the noise disappears, the nozzle to be inspected immediately before is re-inspected, and when there is no noise in the subsequent noise inspection, the previous noise 3. The liquid ejection apparatus according to claim 1, wherein the liquid ejection device is a means for inspecting a nozzle to be inspected next while omitting the inspection.   The liquid ejecting apparatus according to claim 3, wherein the inspection unit is a unit that performs the noise inspection every time without omitting the noise inspection even when there is no noise in the subsequent noise inspection.   The inspection means inspects the nozzle to be inspected by performing the ejection inspection when there is no noise in the previous noise inspection prior to the ejection inspection, and the noise disappears when there is noise in the previous noise inspection. The means for inspecting the nozzle to be inspected immediately before by the ejection inspection when the noise inspection is repeated and the noise is eliminated, and inspecting the nozzle to be inspected next when there is no noise in the previous noise inspection. The liquid ejection device according to claim 1 or 2. A nozzle inspection method for a liquid ejection device comprising: a first electrode that ejects liquid from a plurality of nozzles; and a second electrode that is provided at a position that can face the first electrode;
Liquid was ejected from one of the plurality of nozzles to be inspected toward the second electrode in a state where a voltage was applied between the first electrode and the second electrode facing each other. Sometimes a discharge inspection for inspecting whether or not liquid is discharged from the nozzle based on a potential change of at least one of the electrodes, and noise based on the potential change when the liquid is not discharged from all of the plurality of nozzles In performing the noise inspection for inspecting the presence or absence of each nozzle, the noise inspection is performed prior to the ejection inspection, and when there is noise in the noise inspection, the noise inspection is repeated until the noise disappears, and the noise inspection is performed. A nozzle inspection method, wherein the ejection inspection is performed when there is no noise.   The program for making a computer implement | achieve the nozzle test | inspection method of Claim 6.

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