JP2012223899A - Liquid ejection device, nozzle inspection method, and program for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently make a nozzle inspection using a plurality of inspection parts.SOLUTION: When the inspection failure of a first inspection circuit 71A out of first to eighth inspection circuits 71A-71H is determined (a), a moving unit is controlled to move first to fifteenth heads 62a-62o so that uninspected nozzles of the first and third heads 62a, 62c facing the first inspection circuit 71A face the inspection circuits (the second to eighth inspection circuits 71B-71H) other than the first inspection circuit 71A (b). The inspection circuit (the second inspection circuit 71B) other than the inspection-disabled first inspection circuit 71A is used to make the nozzle inspection of the uninspected nozzles and to determine the ejection propriety of all the uninspected nozzles. Consequently, even if failing to inspect the presence or absence of ejection by the inspection-disabled inspection circuit, the ejection propriety of all the uninspected nozzles can be determined using the other inspection circuits.

Description

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

  2. Description of the Related Art Conventionally, a liquid ejecting apparatus that determines whether or not liquid is ejected from a plurality of nozzles formed on a head 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 ejecting apparatus disclosed in Patent Document 1, as nozzle inspection of a head in which more than 1000 nozzles are formed on a nozzle plate, 15 nozzles are used as one block, and nozzle inspection is performed for each block. In addition, one noise inspection period (also referred to as a non-ejection dummy period) is provided every time one block of nozzle inspection is performed, and whether noise is mixed during nozzle inspection depending on whether noise has occurred during this period. Check for no. That is, if noise does not occur during the noise inspection period, the nozzle inspection of the block immediately before is validated, and if noise occurs, the nozzle 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 nozzle inspection, the erroneous determination is invalidated by performing noise inspection. be able to. When the nozzle inspection is invalidated due to noise, the nozzle inspection is repeated again.

JP 2010-64309 A

  However, simply repeating the nozzle inspection when an abnormality such as noise occurs is inefficient because the nozzle inspection may not be completed indefinitely or may be delayed.

  The present invention has been made in view of the above-described problems, and a main object thereof is to efficiently perform nozzle inspection using a plurality of inspection units.

The liquid ejection device of the present invention is
A head unit comprising a first nozzle group and a second nozzle group comprising a plurality of nozzles for discharging liquid;
An inspection unit including a first inspection unit and a second inspection unit that inspects the presence or absence of ejection from the nozzle opposite to the head unit;
Moving means for relatively moving the head unit and the inspection unit;
The moving means is controlled so that the first nozzle group and the first inspection section face each other, and the second nozzle group and the second inspection section face each other, and the liquid from the nozzles of the first nozzle group sequentially. Based on the inspection result of the first inspection unit when the liquid is discharged, the quality of discharge of the nozzle is determined, and the inspection of the second inspection unit when the liquid is sequentially discharged from the nozzles of the second nozzle group Processing means for performing discharge determination for determining whether the discharge of the nozzle is good or not based on the result;
With
In performing the discharge determination, the processing means, when an abnormal condition that can be regarded as abnormal in the first inspection unit is satisfied, at least of uninspected nozzles that have not determined whether the discharge is good or not in the first nozzle group. The moving means is controlled so that a part and the second inspection section are opposed to each other, and liquids are sequentially discharged from the nozzles of the first nozzle group that are not inspected facing the second inspection section. Determining whether the discharge of the nozzle is good or not based on the inspection result of the second inspection unit when
Is.

  In the liquid ejection apparatus, the moving unit is controlled so that the first nozzle group and the first inspection unit face each other, and the second nozzle group and the second inspection unit face each other, so that the first nozzle The quality of the discharge of the nozzle is determined based on the inspection result of the first inspection unit when the liquid is sequentially discharged from the nozzles of the group, and the liquid when the liquid is sequentially discharged from the nozzles of the second nozzle group Based on the inspection result of the second inspection unit, discharge determination is performed to determine whether or not the nozzle is discharged. In performing the discharge determination, when an abnormal condition that can be regarded as abnormal in the first inspection unit is satisfied, at least a part of the uninspected nozzles in the first nozzle group that have not determined whether or not the discharge is good When the moving means is controlled so as to face the second inspection section, and the uninspected nozzles facing the second inspection section in the first nozzle group are sequentially ejected with liquid from the nozzles. Whether or not the nozzle is discharged is determined based on the inspection result of the second inspection unit. That is, when an abnormal condition that can be considered that there is an abnormality in the first inspection unit is satisfied, the second nozzle is set to at least some of the uninspected nozzles of the first nozzle group that should normally be inspected by the first inspection unit. Whether or not the ejection is good is determined using an inspection unit. Accordingly, compared with the case where the first nozzle group is inspected only by the first inspection unit despite the abnormality, the nozzle inspection can be efficiently performed using a plurality of inspection units.

  In the liquid ejection apparatus according to the aspect of the invention, when the condition that the processing unit can be regarded as being incapable of inspecting the presence / absence of ejection by the first inspection unit is established as the abnormal condition, the processing unit and the uninspected nozzle of the first nozzle group 2 Control the moving means so as to face the inspection unit, and determine whether the uninspected nozzle is discharged based on the inspection result of the second inspection unit when the liquid is sequentially discharged from the uninspected nozzle. A determination process may be performed to determine whether or not all uninspected nozzles are discharged based on the inspection result of the second inspection unit. In this way, even if the first inspection unit cannot inspect the presence or absence of ejection, the second inspection unit can be used to determine the quality of ejection of all uninspected nozzles in the first nozzle group.

  In the liquid ejection apparatus according to the aspect of the invention, the processing unit may be configured as the abnormal condition in a state where the first nozzle group and the first inspection unit face each other and the second nozzle group and the second inspection unit face each other. When the first inspection unit can inspect whether or not there is ejection, but the condition that the completion of the ejection quality determination of all the nozzles of the first nozzle group can be regarded as being delayed as compared with the second nozzle group is satisfied, the second As long as the uninspected nozzles of the nozzle group do not deviate from the position facing the second inspection part, at least some of the uninspected nozzles of the first nozzle group face the second inspection part and the rest are the first. The moving means is controlled so as to face the inspection section, and the uninspected nozzles facing the second inspection section and the uninspected nozzles of the second nozzle group in the first nozzle group are sequentially liquidated from the nozzles. Spit Based on the inspection result of the second inspection unit when the nozzles are discharged, the quality of ejection of the nozzles is determined, and the uninspected nozzles facing the first inspection unit in the first nozzle group are sequentially liquidated from the nozzles. Whether or not the nozzle is discharged may be determined based on the inspection result of the first inspection unit when the nozzle is discharged. In this way, when the completion of the ejection quality determination of all the nozzles of the first nozzle group by the first inspection unit is delayed as compared with the second nozzle group, a part of the uninspected nozzles of the first nozzle group is set to the second. Since the inspection is performed using the inspection unit, the total nozzle inspection time can be shortened.

  In the liquid ejection apparatus according to the aspect of the invention, the head unit includes a first electrode that contacts the liquid, and the first inspection unit and the second inspection unit include a second electrode that can face the first electrode. In a discharge inspection period in which liquid is discharged from the facing nozzle toward the second electrode in a state where the first electrode and the second electrode are opposed to each other and a voltage is applied between the electrodes. An operation for detecting an electrical change between both electrodes and detecting an electrical change between both electrodes in a noise inspection period in which liquid is not discharged from all of the opposing nozzles is performed for each of the opposing nozzles. The presence or absence of ejection and the presence or absence of noise are inspected based on the signal relating to the electrical change, and the processing means determines whether or not the nozzles are ejected based on the presence or absence of ejection and the presence or absence of noise as the inspection results. Constant and may determine the success or failure of the abnormal condition based on an electrical change between the electrodes in the noise test period.

The nozzle inspection method of the present invention includes:
A head unit having a first nozzle group and a second nozzle group each composed of a plurality of nozzles that eject liquid, and a first inspection unit and a second inspection unit that inspect the presence or absence of ejection from the nozzles facing the head unit. A nozzle inspection method for a liquid ejection apparatus, comprising: an inspection unit including: a moving unit that relatively moves the head unit and the inspection unit;
The moving means is controlled so that the first nozzle group and the first inspection section face each other, and the second nozzle group and the second inspection section face each other, and the liquid from the nozzles of the first nozzle group sequentially. Based on the inspection result of the first inspection unit when the liquid is discharged, the quality of discharge of the nozzle is determined, and the inspection of the second inspection unit when the liquid is sequentially discharged from the nozzles of the second nozzle group In performing the discharge determination for determining whether or not the nozzle is discharged based on the result, when an abnormal condition that can be considered that the first inspection unit is abnormal is satisfied, the discharge quality of the first nozzle group is determined. The moving means is controlled so that at least a part of uninspected nozzles and the second inspection part face each other, and the uninspected nozzles that face the second inspection part in the first nozzle group Discharges liquid sequentially from the nozzle Determining the quality of the discharge of the nozzle on the basis of the second inspection unit of the inspection results obtained while,
Is included.

  According to this nozzle inspection method, at least a part of the uninspected nozzles of the first nozzle group that should normally be inspected by the first inspection unit when an abnormal condition that allows the first inspection unit to be considered abnormal is satisfied. In order to determine the quality of ejection using the second inspection unit, the plurality of inspection units are compared with the case where the first nozzle group is inspected only by the first inspection unit even though there is an abnormality. The nozzle inspection can be efficiently performed using In this nozzle inspection method, various aspects of the above-described liquid ejecting apparatus may be employed, and steps for realizing each function of the above-described liquid ejecting apparatus may be added.

  The program of the present invention is for causing a computer to realize the nozzle inspection method described 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, the above-described steps of the nozzle inspection method of the present invention are realized, so that the same effects 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 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 the determination result in a detection signal and a detection control part. A table when the nozzles of the first head 62a are divided into blocks. The flowchart of the integrated determination routine of a nozzle. Explanatory drawing of the data stored in the memory of the detection control part 76. FIG. The flowchart of a digital signal output routine. Explanatory drawing which shows an example of the data of the register for transmission of the detection control part. Explanatory drawing which shows an example of the result of integrated determination. The flowchart of a process routine at the time of a test impossible. Explanatory drawing which shows a mode that a process routine at the time of an inspection impossible is performed. The flowchart of a processing routine at the time of delay. Explanatory drawing which shows a mode that a nozzle test | inspection is performed sequentially. Explanatory drawing which shows the state in the time t1, t2, t3 of FIG.

  Next, an embodiment embodying the present invention will be described. 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 the personal computer PC, inputs print data from the personal computer PC, 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 personal computer PC via the interface unit 26. Each unit is controlled via the unit control circuit 24 while temporarily storing data in 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 that ink is ejected 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. As shown in FIGS. 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. To do. 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 arranged 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 that ink is ejected 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. The inspection unit 70 includes an inspection circuit 71. The inspection circuit 71 is basically formed at a rate of one for each of the two heads 62. In the present embodiment, the number of heads is fifteen, and thus eight inspection circuits 71 are formed corresponding thereto. . For convenience of explanation, the eight inspection circuits 71 are referred to as a first inspection circuit 71A, a second inspection circuit 71B,. FIG. 7 is an explanatory diagram showing the configuration of one of the inspection circuits 71 of the inspection unit 71. The inspection circuit 71 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 that applies a voltage between the inspection electrode 72 and the nozzle plate 63 of the head 62. 74, 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 while 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.

  As described above, since the inspection circuit 71 is basically formed at a ratio of one to the two heads 62, the inspection electrode 72 is basically formed at a ratio of one to the two heads 62. ing. 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. Each of the inspection electrodes 72 is arranged so that the interval between the inspection electrode 72 and the other inspection electrode 72 adjacent in the Y direction is equal, and from the upper end of the inspection electrode 72, the other inspection electrode 72 adjacent in the Y direction. Let the distance to the upper end of L be the distance L. 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. In the inspection of the nozzle to be inspected, the controller 20 performs a discharge inspection for checking whether ink can be discharged satisfactorily, and a noise inspection for checking whether noise that affects the determination result has occurred during the discharge inspection. carry out.

  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 so that ink is ejected 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. 6) 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. An example of the detection signal output from the amplifier 77 at that time and the determination result in the detection control unit 76 is shown in FIG. 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.

  Next, a nozzle integration determination routine executed by the controller 20, an inspection impossible processing routine and a delay processing routine that are processing when the inspection circuit 71 is abnormal, and a digital signal output executed by the detection control unit 76 of the inspection unit 70 The routine will be described. Here, nozzles are processed in units of blocks. For this reason, prior to the description of each routine, how to divide the blocks will be described. For each head 62, the block divides a plurality of nozzles of the head 62 so that 15 nozzles form one block. FIG. 11 is a table showing a state when 1440 (180 × 8 columns) nozzles of the first head 62a are divided into blocks. Specifically, in the Mk column, # 1 to # 15 are first blocks, # 16 to # 30 are second blocks, and so on, and then the Gr column, Or column, Cl column, Block division is performed in the same order in the order of Pk column, Cy column, Ma column, and Ye column. The second to fifteenth heads 62b to 62o are also divided into blocks in the same manner as in FIG.

  The nozzle integration determination routine will be described with reference to the flowchart of FIG. The controller 20 starts this integration determination routine every time the execution timing of the integration determination arrives. 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). Thereby, each head 62 and each test electrode 72 have the positional relationship shown in FIG. Next, one of the heads 62 facing each test electrode 72 is set as a test target head for each test electrode 72 (step S105). In addition, the process after step S105 in an integrated determination routine is performed independently about each of eight test | inspection circuits 71A-H. Further, in the present embodiment, when there are a plurality of heads 62 facing each inspection electrode 72, the head 62 positioned on the upper side in FIG. 8 is set as the inspection target head first. Therefore, for example, when the processing after step S105 is performed for the first inspection circuit 71A, the first head 62a is first set as the inspection target head in step S105, and the processing after step S105 is performed for the second inspection circuit 71B. In step S105, first, the fifth head 62e is set as an inspection target head. The same applies to the other inspection circuits 71. Since the eighth inspection circuit 71H faces only the fourteenth head 62n, the fourteenth head 62n is set as the inspection target head in step S105.

  Subsequently, a value 1 is set to the variable p representing the block number (step S110), the p-th block is set as the inspection target block (step S120), and the inspection target block is inspected (step S130). Specifically, the controller 20 sequentially sets 15 nozzles belonging to the p-th block of the inspection target head as inspection target nozzles, and supplies the drive signal COM shown in FIG. 9A to the piezo element of the inspection target nozzle. Is continuously applied twice, and thereafter, the drive signal COM is not applied for a predetermined period. As a result, the nozzle to be inspected is subjected to two ejection inspections and one noise inspection. The detection control unit 76 of the inspection unit 70 detects two discharge inspection detection signals output from the amplifier 77 and one noise inspection detection while a voltage is applied between the inspection electrode 72 and the nozzle plate 63. The signal is acquired and stored in a temporary storage area (not shown) of the detection control unit 76. Then, after temporarily storing each of the three detection signals for all 15 nozzles belonging to the p-th block, the detection control unit 76 executes a digital signal output routine. FIG. 13 shows data stored in the temporary storage area of the detection control unit 76 at this time. The first to third data are detection signals for the discharge inspection (first time), discharge inspection (second time), and noise inspection for the smallest nozzle (# 1 or # 2) belonging to the p-th block. Yes, the 4th to 6th data are detection signals for the discharge inspection (first time), discharge inspection (second time), and noise inspection for the nozzle having the second smallest number among the nozzles belonging to the p-th block. Since the meanings of the subsequent data are the same, the description thereof is omitted.

  Here, a digital signal output routine executed by the detection control unit 76 will be described with reference to the flowchart of FIG. This routine is started when detection of detection signals of all the nozzles included in the p-th block is completed, that is, when all 1 to 45 pieces of data are stored in the temporary storage area shown in FIG. When this routine is started, the detection control unit 76 first sets a value 1 to the variable k (step S310). Subsequently, the kth data is read from the temporary storage area of the detection control unit 76 (step S320), and it is determined whether the data, that is, the amplitude Va of the detection signal exceeds the threshold value Vth (step S330). If the amplitude Va exceeds the threshold value Vth, a digital signal indicating “large amplitude” is written in a kth position of a transmission register (not shown) of the detection control unit 76 (step S340). On the other hand, if the amplitude Va is equal to or less than the threshold value Vth, a digital signal indicating “small amplitude” is written in the kth position of the transmission register of the detection control unit 76 (step S350). Then, after the writing to the transmission register is completed in step S340 or step S350, the variable k has reached the upper limit value (here, the upper limit value is 45 because the number of nozzles included in one block is 15). (Step S360), and if the variable k has not reached the upper limit, the variable k is incremented by 1 (step S370), and the process returns to step S320 again. On the other hand, if the variable k has reached the upper limit value, the contents of the transmission register are transmitted to the controller 20 (step S380), and this routine is terminated. That is, after the digital signal (45 digital signals) corresponding to the full capacity of the transmission register is stored, the detection control unit 76 transmits the contents of the transmission register to the controller 20. The data in the transmission register at this time is shown in FIG.

  Returning to FIG. 12, the controller 20 determines whether or not one block of digital signals (45 digital signals) has been acquired from the detection control unit 76 (step S140). If not, the process returns to step S140. Return. On the other hand, if a digital signal for one block is acquired from the detection control unit 76, the integration determination is performed, and the nozzles are associated with the integration determination result (step S150). For example, when the block to be inspected is the first block, the first to third digital signals out of 45 digital signals are the ejection inspection (first time) and the ejection inspection (second time) of the # 1 nozzle in the Mk row. The 4th to 6th digital signals represent the results of the ejection test (first time), the ejection test (second time), and the noise test of the nozzle # 2 in the Mk column. Identify which nozzle the digital signal corresponds to. At the same time, for the specified nozzle, three digital signals corresponding thereto are integrated and determined to be normal or abnormal. It should be noted that the determination of normal or abnormal (integrated determination) is as already described with reference to FIG. After performing the integrated determination in this way, the integrated determination result is associated with the identified nozzle. An example is shown in FIG. 16A shows a digital signal from the inspection control unit 76, and FIG. 16B shows a result of the integrated determination for each nozzle.

  Subsequently, the controller 20 determines whether or not there is an “unknown” result as a result of the integration determination of 15 nozzles included in the p-th block (step S160). If there is an "unknown" item in step S160, the reinspection count S is incremented by 1 (step S170), and it is determined whether or not the inspection circuit 71 cannot be inspected (step S180). Specifically, it is determined whether or not the number of retests S exceeds the threshold value Sth, and when it exceeds, it is determined that the test circuit 71 cannot be tested. Here, the reinspection number S is a value representing the number of repetitions of step S190 (described later) for setting the current p-th block as the inspection target block again, and the initial value is set to zero. The threshold value Sth is a value set as the upper limit value (for example, value 5) of the number of repetitions of step S190. In this embodiment, when there is an “unknown” nozzle integration determination result, re-inspection is performed as described later. When this re-inspection count S exceeds the threshold value Sth, the inspection circuit In step S180, it is determined that the inspection cannot be performed. If a negative determination is made in step S180, it is determined that the inspection is not possible, the current p-th block is set as the inspection target block again (step S190), and the process returns to step S130. As a result, re-inspection is performed in units of blocks.

  If there are no unknown nozzles in the first inspection or if there are no unknown nozzles due to re-inspection, a negative determination is made in step S160, the re-inspection count S is initialized to 0 (step S215), and the p-th block Correspondences between the 15 identified nozzles and the integrated determination result are determined and stored in the memory 28 (step S220). Thereafter, it is determined whether or not the variable p has reached the upper limit value (here, the total number of blocks) (step S230). If the variable p has not reached the upper limit value, the variable p is incremented by 1 (step S240). The process returns to step S120 again. As a result, the next block is inspected.

  If the variable p has reached the upper limit value in step S230, it is determined whether there is an uninspected head 62 that faces the inspection electrode 72 (step S250). For example, regarding the first inspection circuit 71A, when the nozzle inspection is performed by setting the first head 62a as the inspection target head in the above-described step S105, the third head 62c facing the first inspection electrode 72A is not inspected. Therefore, a positive determination is made in step S250. If a positive determination is made, an uninspected head is set as the next inspection target head (step S260), and the process returns to step S110. As a result, nozzle inspection is performed for an uninspected head. When there is no uninspected head facing the inspection electrode 72, an affirmative determination is made in step S250, and this routine is terminated.

  On the other hand, when the reexamination is repeated, the unknown nozzle does not disappear, and when the reinspection number S exceeds the threshold value Sth, an affirmative determination is made in step S180, and the inspection circuit 71 and the uninspected nozzle that are determined as incapable of inspection. Is stored in the memory 28 (step S270), and this routine is terminated. As described above, since the processing after step S105 is performed independently for each of the eight inspection circuits 71A to 71H, the inspection in which the positive determination is made in step S180 among the eight inspection circuits A to H. The memory 71 stores the circuit 71 and the untested nozzle that should have been subjected to the nozzle test by the test circuit 71 but has not yet performed the nozzle test. For example, the processing after step S105 is performed on the inspection circuit 71A, and the head to be inspected when the positive determination is made in step S180 is the first head 62a, and the block to be inspected is the fifth block (the variable p is a value of 5). In this case, the inspection circuit 71 that cannot be inspected is the first inspection circuit 71A, and the nozzles of the fifth to 96th blocks of the first head 62a and the first to 96th blocks of the third head 62c are uninspected nozzles. The fact is stored in the memory 28.

  By performing the above integrated determination routine, the nozzle inspection of each head 62 is performed. Specifically, the nozzle inspection of the first head 62a and the third head 62c using the first inspection circuit 71A, the nozzle inspection of the fifth head 62e and the seventh head 62g using the second inspection circuit 71B, the third inspection Nozzle inspection of ninth head 62i and eleventh head 62k using circuit 71C, thirteenth head 62m using fourth inspection circuit 71D, nozzle inspection of fifteenth head 62o, second head using fifth inspection circuit 71E 62b, nozzle inspection of the fourth head 62d, nozzle inspection of the sixth head 62f, eighth head 62h using the sixth inspection circuit 71F, nozzles of the tenth head 62j, twelfth head 62l using the seventh inspection circuit 71G Inspection and nozzle inspection of the fourteenth head 62n using the eighth inspection circuit 71H are performed. If there is an inspection circuit 71 that has been determined to be uninspectable in step S180 described above, at least some of the nozzles of the head 62 that face the inspection circuit 71 will be subjected to nozzle inspection even if the integrated determination routine ends. This is an uninspected nozzle that is not performed.

  Next, the processing routine when the inspection is impossible will be described with reference to FIG. The non-inspection processing routine is for performing a nozzle inspection by another inspection circuit 71 for an uninspected nozzle that should have been subjected to a nozzle inspection using the inspection circuit 71 that has been determined to be uninspectable by the integrated determination routine. . When the above-described integrated determination routine for all of the inspection circuits 71A to 71H is completed, the controller 20 executes this inspection impossible processing routine. When this routine is started, the controller 20 first determines whether or not there is an inspection circuit 71 that is determined to be uninspectable in the integrated determination routine (step S410). This determination is performed by examining the memory 28 and determining whether or not there is an uninspectable inspection circuit 71 stored in step S270 of the above-described integrated determination routine. If the inspection circuit 71 that cannot be inspected is not stored in the memory 28, a negative determination is made and this routine is terminated.

  When the inspection circuit 71 that cannot be inspected is stored in the memory 28, an affirmative determination is made in step S 410, and an uninspected nozzle that faces the inspection circuit 71 that cannot be inspected is made to face another inspection circuit 71. (Step S420). This process is performed by the controller 20 moving the head unit 60 by controlling the moving unit 50. Note that it is specified by examining the uninspected nozzle stored in step S270 which of the uninspected nozzles faces the inspection circuit 71 that cannot be inspected. Then, using the inspection circuit 71 facing the uninspected nozzle after the movement, a nozzle inspection is performed for the uninspected nozzle (step S430), and this routine is finished.

  Here, the state of performing the processing routine when the inspection is impossible will be described with reference to FIG. For example, when performing the processing after step S105 of the integration determination routine using the first inspection circuit 71A, the nozzle inspection for the first to 48th blocks of the first head 62a is completed, and the nozzle inspection for the 49th block is performed. , It is assumed that the unknown nozzle does not disappear and the number of retests S exceeds the threshold value Sth. In this case, an affirmative determination is made in step S180 of the integrated determination routine when the variable p is 49, and the inspection circuit 71A cannot be inspected in step S270, and the 49th to 96th blocks of the first head 62a. The fact that the nozzles of the first to 96th blocks of the third head 62c are uninspected nozzles is stored in the memory 28. Examples of the case where the unknown nozzle does not disappear in this way include a case where ink is accumulated on the inspection electrode 71 and noise is generated by the ink. Assuming that the integrated determination routine is completed without being incapable of inspecting the other inspection circuits 71B to 71H, the state shown in FIG. That is, the first inspection circuit 71A is not inspected, and the nozzles of the 49th to 96th blocks of the first head 62a and the nozzles of the first to 96th blocks of the third head 62c have not been subjected to nozzle inspection and remain uninspected nozzles. It has become. In addition, the nozzle inspection of all the nozzles of the other heads 62 has been completed. In this state, when the inspection impossible processing routine is performed, an affirmative determination is made in step S410, the moving unit 50 is controlled in step S420, and inspection circuits other than the first inspection circuit 71A incapable of inspecting uninspected nozzles The head unit 60 is moved to the lower end side in the Y direction so as to face each other. As a result, the state shown in FIG. That is, the nozzles of the 49th to 96th blocks of the first head 62a and the first to 96th blocks of the third head 62c, which are uninspected nozzles, face the second electrode 72B of the second inspection circuit 71B. In subsequent step S430, the nozzle inspection of the uninspected nozzle is performed using the second inspection circuit 71B. This nozzle inspection may be performed in the same manner as step S105 and subsequent steps in the integrated determination routine described above. For example, in the case of the state of FIG. 18B, instead of steps S105 and S110, the inspection target head is set to the first head 62a and the variable p is set to the value 49, and the processing after step S120 is performed. Can be done. Thereby, the nozzle inspection of the uninspected nozzle is performed using the second inspection circuit 71B. When the nozzle inspection is completed, the processing routine when the inspection is impossible is terminated. By performing the inspection impossible processing routine in this manner, even if there is an inspection circuit 71 that cannot be inspected, the nozzle inspection of the uninspected nozzle can be performed using another inspection circuit 71. In FIG. 18B, the nozzle inspection is performed with the inspection electrode 72B of the second inspection circuit 71B opposed to the uninspected nozzle. However, the nozzle inspection may be performed by the inspection circuit 71 that is not inspectable. Any of the inspection electrodes 72 of the circuit 71C to the eighth inspection circuit 71H may be opposed to the uninspected nozzle. If the inspection circuit 71 closest to the inspection circuit 71 that cannot be inspected is opposed to the uninspected nozzle so that the time required for moving the head unit 62 is reduced, the total nozzle inspection time can be shortened.

  Next, the delay processing routine will be described with reference to FIG. In this delay processing routine, when performing nozzle inspection using the eight inspection circuits 71, the non-inspected nozzles of the inspection circuit 71 in which the nozzle inspection is delayed are inspected using the other inspection circuits 71, and the nozzle inspection is performed. This is to shorten the total time. The controller 20 repeatedly executes this delay time processing routine at predetermined time intervals during execution of the integration determination routine.

  When this routine is started, the controller 20 first determines whether there is any of the eight inspection circuits 71 whose nozzle inspection is delayed compared to the other inspection circuits 71 (step S510). . This determination is made, for example, by comparing the inspection circuit 71 having the smallest number of blocks completed with the nozzle inspection among the eight inspection circuits 71 with the inspection circuit 71 having the largest number of blocks. This is performed by determining whether or not the threshold is equal to or greater than the threshold value. This determination is performed only by the other inspection circuits 71 except for the inspection circuit 71 that is determined to be uninspectable in step S180. When a negative determination is made, this routine is terminated as it is.

  When a positive determination is made in step S510, the moving direction of the head unit 60 is set (step S520). As will be described in detail later, this moving direction is a moving direction for inspecting an uninspected nozzle of the head 62 facing the inspection circuit 71 in which the nozzle inspection is delayed by using another inspection circuit 71. In the present embodiment, this moving direction is set depending on which inspection circuit 71 has been determined that the nozzle inspection is delayed in step S510. Specifically, when the inspection circuit 71 that has been determined that the nozzle inspection is delayed is one of the first inspection circuit 71A, the second inspection circuit 71B, the fifth inspection circuit 71E, and the sixth inspection circuit 71F. The moving direction of the head unit 60 is set to the lower end side in the Y direction. On the other hand, when the inspection circuit 71 determined to have delayed the nozzle inspection is one of the third inspection circuit 71C, the fourth inspection circuit 71D, the seventh inspection circuit 71G, and the eighth inspection circuit 71H, the head unit The moving direction of 60 is set to the upper end side in the Y direction.

  Subsequently, it is determined whether or not the head unit 60 can be moved in the movement direction set in step S520 (step S530). Specifically, it is determined whether or not the untested nozzle of the head 62 does not deviate from the position facing the test electrode 72 when the head unit 60 is moved by a predetermined distance in the moving direction set in step S520. The reason for making such a determination will be described later. In the present embodiment, the predetermined distance is a half of the distance L shown in FIG. If a negative determination is made in step S530, this routine is terminated as it is.

  On the other hand, if an affirmative determination is made in step S530, the head unit 60 is moved to step S520 so that an uninspected nozzle that faces the inspection circuit 71 that is determined to be delayed in the nozzle inspection faces another inspection circuit 71. Is moved by a predetermined distance in the moving direction set in (Step S540). Then, using the inspection circuit 71 facing the uninspected nozzle after the movement, nozzle inspection for the uninspected nozzle is started (step S550), and this routine is ended. Specifically, step S550 is performed as follows. That is, first, the integrated determination routine that has been executed is canceled. Then, the inspection target head and inspection target block of each inspection circuit 71 are processed as a process in place of steps S105, S110, and S120 so that the nozzle inspection of the uninspected nozzle is performed using the inspection circuit 71 that faces the uninspected nozzle after the movement. Is newly set, and the processing after step S130 of the integration determination routine is started again.

  Here, the state of performing this delay processing routine will be described with reference to FIGS. FIG. 20 is an explanatory diagram showing a state in which the integrated determination routine is started from time t0 and nozzle inspection using each inspection circuit 71 is sequentially performed. FIG. 21 is an explanatory diagram showing the state of each inspection electrode 72 and each head 62 at times t1, t2, and t3 in FIG. In FIG. 20, the numbers in parentheses represent the block numbers of the heads 62. As shown in FIG. 20A, when the integrated determination routine is started from time t <b> 0, the controller 20 starts the integrated determination routine and sequentially performs nozzle inspection using each inspection circuit 71. Further, the delay time processing routine is repeatedly executed every predetermined time from time t0. Then, for example, the processing speed of each inspection circuit 71 varies, or an unknown nozzle is frequently generated and re-inspected although it is not affirmatively determined in step S180 in the integrated determination routine. Assume that the nozzle inspection of 71A is delayed. In such a case, the difference in the number of blocks in which the nozzle inspection has been completed increases with time in the first inspection circuit 71A having the smallest number of blocks in which the nozzle inspection has been completed and the other inspection circuit 71 having the largest number of blocks. . Then, in the delay processing routine executed at time t1, if the difference becomes equal to or greater than a predetermined threshold value for the first time, an affirmative determination is made in step S510. The state of each inspection electrode 72 and each head 62 at this time is shown in FIG. If an affirmative determination is made in step S510, since it is the first inspection circuit 71A that is delayed, the moving direction of the head unit 60 is set to the lower end side in the Y direction in step S520. Subsequently, in step S530, it is determined whether or not the head unit 60 can be moved. Here, as shown in FIGS. 20A and 21A, at the time t1, the nozzles of the 86th to 96th blocks of the fifteenth head 62o facing the fourth inspection electrode 72D are uninspected nozzles. is there. Therefore, if the head unit 60 is moved by a predetermined distance (distance L / 2 toward the lower end side in the Y direction), the uninspected nozzles of the fifteenth head 62o are displaced from the positions facing the inspection electrodes 72. That is, the uninspected nozzle does not face any inspection electrode 72, and in this state, the uninspected nozzle cannot be inspected. Therefore, a negative determination is made in step S530, and the delay time processing routine is terminated without moving the head unit 60. As described above, the determination in step S530 prevents the uninspected nozzles from moving away from the position facing the inspection electrode 72 due to the movement of the head unit 60, and the uninspected nozzles that cannot perform the nozzle inspection in the moved state. It does not occur.

  Next, consider the case where the delay processing routine is executed at time t2. The state at this time is shown in FIG. 20 (b) and FIG. 21 (b). When the delay time processing routine is executed, since the nozzle inspection by the first inspection circuit 71A is delayed even at time t2, a positive determination is made in step S510, and in step S520, the movement direction is set on the lower end side in the Y direction. . In the subsequent step S530, since the nozzle inspection using the fourth inspection electrode 72D is completed unlike the time t1, the head 62 is inspected even if the head unit 60 is moved to the lower end side in the Y direction by a predetermined distance. There is no uninspected nozzle that deviates from the position facing the electrode 72. Therefore, the head unit 60 is movable and a positive determination is made in step S530. In step S540, the head unit 60 is moved by a predetermined distance (L / 2). The state at time t3 immediately after the movement of the head unit 60 is shown in FIGS. 20 (c) and 21 (c). As shown in the drawing, this movement changes the head 62 facing each inspection electrode 72. As a result, of the first head 62a and the third head 62c that are opposed to the first inspection circuit 71A that is delayed in inspection, the third head 62c is opposed to the second inspection circuit 71B. And the process of step S550 is performed and the test | inspection of an untested nozzle is started from the time t3 after a movement. Specifically, nozzle inspection is started from the 91st block of the first head 62a using the first inspection circuit 71A, and nozzle inspection is started from the first block of the third head 62c using the second inspection circuit 71B. The nozzle inspection is started from the 75th block of the seventh head 62g using the third inspection circuit 71C, the nozzle inspection is started from the 78th block of the 11th head 62k using the fourth inspection circuit 71D, and the sixth inspection is started. The inspection of each inspection circuit 71 is started by starting the nozzle inspection from the 85th block of the fourth head 62d using the circuit 71F and starting the nozzle inspection from the 90th block of the twelfth head 62h using the eighth inspection circuit 71H. The target head and the inspection target block are set, and the processing after step S130 of the integrated determination routine is performed for each inspection circuit 71. As can be seen from FIG. 21C, the fifth inspection circuit 71E and the seventh inspection circuit 71G do not perform nozzle inspection because there is no uninspected nozzle in the opposing head 62.

  As described above, the total processing time of the nozzle inspection can be shortened by performing the delay processing routine. That is, if the nozzle inspection of the first head 62a and the third head 62c is performed as it is using the first inspection circuit 71A in which the nozzle inspection is delayed without performing the delay processing routine, the nozzles of the first inspection circuit 71A If the inspection speed remains low, inspection of all nozzles is completed at time t5 shown in FIGS. 21 (a) and 21 (b). On the other hand, when the processing routine at the time of delay is performed, the third head 62c that should have been inspected by the first inspection circuit 71A is inspected using the second inspection circuit 71B in which the nozzle inspection speed is not slow. As shown in c), all nozzle inspections are completed at time t4 earlier than time t5.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. The inspection circuit 71 (first inspection circuit 71A in FIG. 18) determined to be inoperable according to the present embodiment and the inspection circuit 71 (first inspection circuit 71A in FIG. 21) determined to have a delay are included in the present invention. An inspection circuit 71 (second inspection circuit 71B to 8th inspection circuit 71H in FIG. 18) that corresponds to the first inspection unit and is not determined to be uninspectable, or an inspection circuit 71 that is not determined to have a delay (FIG. 18). 21, the second inspection circuit 71 </ b> B to the eighth inspection circuit 71 </ b> H) correspond to the second inspection unit, and it is determined that the inspection circuit 71 (first inspection circuit 71 </ b> A in FIG. 18) determined to be uninspectable or a delay occurs. The head 62 (the first head 62a and the third head 62c in FIGS. 18 and 21) facing the inspection circuit 71 (in FIG. 21, the first inspection circuit 71A) in step S100 corresponds to the first nozzle group of the present invention. And can not be inspected Inspection circuit 71 (second inspection circuit 71B to eighth inspection circuit 71H in FIG. 18) that is not defined or inspection circuit 71 that is not determined to have a delay (second inspection circuit 71B to eighth inspection in FIG. 21) The head 62 facing the circuit 71H) in step S100 (in FIGS. 18 and 21, the second head 62b and the fourth head 62d to the fifteenth head 62o) correspond to the second nozzle group, and the inspection unit 70 corresponds to the inspection unit. The moving unit 50 corresponds to a moving unit, and the controller 20 corresponds to a determination unit. The nozzle plate 63 corresponds to the first electrode, and the inspection electrode 72 corresponds to the second electrode. 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, when it is determined that there is an abnormality in any of the inspection circuits 71, the unexamined nozzles of the head 62 that face the inspection circuit 71 determined to be abnormal in step S100. The moving unit 50 is controlled so that at least a part of the test circuit 71 and the test circuit 71 other than the test circuit 71 determined to be abnormal face each other, and the test circuit 71 other than the test circuit 71 determined to be abnormal is used. A nozzle inspection for the inspection nozzle is performed to determine whether or not the uninspected nozzle is discharged. For this reason, a plurality of inspection units are provided for the non-inspected nozzles of the head 62 that faced the abnormal inspection circuit 71 in step S100, as compared with the case of inspecting the non-inspected nozzles only with the abnormal inspection circuit 71. It is possible to efficiently perform the nozzle inspection.

  According to the printer 10 of the present embodiment described above, when it is determined that any of the inspection circuits 71 cannot be inspected due to an abnormality in the inspection circuit 71, the head that has faced the inspection circuit 71 that cannot be inspected in step S100. The moving unit 50 is controlled so that the 62 uninspected nozzles and the inspection circuits 71 other than the uninspectable inspection circuit 71 face each other, and the uninspected nozzles are inspected using the inspection circuit 71 other than the uninspectable inspection circuit 71. Nozzle inspection is performed to determine whether all uninspected nozzles are discharged. For this reason, even when the inspection circuit 71 that cannot be inspected cannot inspect the presence or absence of ejection, it is possible to determine the quality of ejection of all the uninspected nozzles using the other inspection circuits 71.

  When it is determined that any of the inspection circuits 71 cannot be inspected but the nozzle inspection is delayed as an abnormality in the inspection circuit 71, an uninspected nozzle facing the inspection circuit 71 that is not delayed is inspected. As long as it does not deviate from the position opposed to 71, at least a part of the delayed inspection circuit 71 is opposed to the other non-delayed inspection circuit 71 and the remaining is opposed to the inspection circuit 71 that is delayed. Then, the moving unit 50 is controlled, and each inspection circuit 71 is used to perform nozzle inspection of uninspected nozzles that face each inspection circuit after movement. In this way, when there is an inspection circuit 71 in which the completion of nozzle inspection is delayed as compared with other inspection circuits 71, some of the uninspected nozzles of the inspection circuit 71 are inspected using other inspection circuits 71 that are not delayed. Therefore, the total nozzle inspection time can be shortened.

  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.

  For example, in the above-described embodiment, when the number of retests S exceeds the threshold value Sth in step S180, it is determined that the test circuit 71 is not testable. Good. For example, when the number of “unknown” nozzles included in the result of the integrated determination of 15 nozzles included in one block in step S160 is equal to or greater than a predetermined threshold value that can be regarded as uninspectable, it is determined that inspection is impossible. May be. Further, when the amplitude Va in the noise inspection period is equal to or greater than a predetermined threshold value (a value larger than the threshold value Vth) that can be regarded as uninspectable, it may be determined that the inspection is impossible.

  In the embodiment described above, in step S510, the inspection circuit 71 having the smallest number of blocks having completed the nozzle inspection is compared with the inspection circuit 71 having the largest number, and the difference in the number of blocks having completed the nozzle inspection is equal to or greater than a predetermined threshold value. Whether or not there is an inspection circuit 71 in which the nozzle inspection is delayed is determined by determining whether or not there is, but may be determined by another method. For example, the total number of times the re-inspection number S is incremented in step S270 is stored as the re-inspection cumulative number for each inspection circuit 71, and this re-inspection cumulative number is equal to or greater than a predetermined threshold value that can be considered that the inspection is delayed. It may be determined that the inspection circuit 71 is delayed.

  In the embodiment described above, the moving direction of the head unit 60 is set depending on which of the inspection circuits 71 is delayed in step S520, but may be set by another method. For example, when the head unit 60 is moved by a predetermined distance in FIG. 8, the direction in which the uninspected nozzle does not deviate from the position facing the inspection electrode 72 may be set as the movement direction. That is, the moving direction may be set so that the head 62 deviating from the position facing the inspection electrode 72 by movement does not include the uninspected nozzle. For example, when there are no uninspected nozzles in the first head 62a and the second head 62b in FIG. 8, the moving direction of the head unit 60 is set upward, and the head unit 60 moves by a predetermined distance (L / 2). When there is no uninspected nozzle at 62o, the moving direction of the head unit 60 may be set downward and moved by a predetermined distance (L / 2).

  In the embodiment described above, the moving distance of the head unit 60 in step S540 is the predetermined distance (L / 2), but other moving distances may be the predetermined distance. For example, assuming that the moving distance is the distance L, all the uninspected nozzles facing the delayed inspection circuit 71 may be opposed to the other inspection circuits 71 to perform the nozzle inspection. Further, the moving distance is determined so that one head 62 faces two inspection circuits 71, one inspection circuit 71 inspects some nozzles of one head 62, and the other nozzles have another one. One inspection circuit 71 may inspect. Further, the moving distance may be variable. For example, when the delayed inspection circuit 71 is currently in the middle of the nozzle inspection of the first head 62, the movement distance is L and the nozzle inspection of the second head 62 is in the middle of the nozzle inspection. The distance may be a distance L / 2.

  In the above-described embodiment, the movement direction set in step S520 is the Y direction, but it may be the X direction. Even in that case, as in the above-described embodiment, the movement may be performed when the uninspected nozzle does not deviate from the position facing the inspection electrode 72 due to the movement. Moreover, you may move to a X direction and a Y direction together. For example, the head unit 60 may be moved in the X direction and the Y direction to a position where the first inspection circuit 71A and the second head 62b and the fourth head 62d face each other.

  In the embodiment described above, the fourth inspection circuit 71D sets the thirteenth head 62m as the inspection target head first, and then sets the fifteenth head 62o as the inspection target head, but first the fifteenth head 62o. May be set as the inspection target head. In this way, the nozzle inspection of the fifteenth head 62o (head close to the end along the moving direction of the head unit 60) that is likely to be detached from the position facing the inspection circuit 71 due to the movement of the head unit 60 is performed preferentially. Since the inspection is completed first, it is easily determined that the movement is possible in step S530, and the nozzle inspection by the plurality of inspection circuits 71 can be performed more efficiently.

  In the embodiment described above, as can be seen from FIGS. 11, 18, and 21, there is no uninspected nozzle from the upstream side in the X direction toward the downstream side for one head 62 (the upstream nozzle is the downstream nozzle). The inspection order of the nozzles is determined so that there is no uninspected nozzle from the upper end side in the Y direction toward the lower end side (the upper end side nozzle is lower than the lower end side nozzle). The inspection order of the nozzles is determined so that the nozzles are not inspected from the lower end side in the Y direction toward the upper end side (the lower end nozzle has priority over the upper end nozzle). The inspection order of the nozzles may be determined as in In this way, for example, the first head 62a and the second head 62b are preferentially inspected from the nozzle on the upper end side in the Y direction, and the fourteenth head 62n and the fifteenth head 62o are on the lower end side in the Y direction. By preferentially inspecting the nozzles from the nozzles, when moving the head unit 60 in the Y direction in the delay time processing routine, the nozzles of the nozzles that are likely to deviate from the position facing the inspection circuit 71 due to the movement of the head unit 60 Inspection is completed preferentially. For this reason, for example, when the distance L / 2 cannot be moved but the uninspected nozzle does not deviate from the position facing the inspection circuit 71 even if the distance L / 3 is moved, the distance L / 3 is moved. Thus, the nozzle inspection by the plurality of inspection circuits 71 can be performed more efficiently.

  In the embodiment described above, the block division is performed in the order shown in FIG. 11 and the nozzle inspection is performed from the first block. However, the block division is not performed, and one nozzle is set as the inspection target nozzle in step S120. In step S130, one inspection target nozzle may be inspected, and the inspection target nozzles may be sequentially set until there are no uninspected nozzles.

  In the above-described embodiment, when there are a plurality of inspection circuits 71 that are determined to be incapable of inspection, the processing routine when incapable of inspection may be performed a plurality of times. In other words, until all the uninspected nozzles are finally removed, the nozzle inspection may be performed by the inspection circuit 71 that is not inspectable, and all the uninspected nozzles are opposed to the inspection circuit 71 that is not inspectable in a single inspection impossible processing routine. There is no need. For example, when it is determined that the first inspection circuit 71A to the seventh inspection circuit 71G cannot be inspected and all of the first head 62a to the thirteenth head 62m and the fifteenth head 62o have uninspected nozzles, the processing routine for inability to inspect is performed. The eighth inspection circuit 71H may be used to perform the nozzle inspection of all the uninspected nozzles by performing 7 times.

  In the above-described embodiment, when there is an inspection circuit 71 that cannot be inspected or when there is an inspection circuit 71 in which a delay in nozzle inspection occurs, the head unit 60 is moved and the inspection circuit 71 of the uninspected nozzle is moved. The inspection is performed. However, the present invention is not limited to this, and any apparatus may be used as long as the head unit 60 is moved when the inspection circuit 71 is abnormal and the inspection circuit 71 without abnormality is inspected. The abnormality of the inspection circuit 71 may be an abnormality of the detection control unit 76 or the high voltage power source 74, for example.

  In the embodiment described above, the moving unit 50 moves the head unit 60 to change the positional relationship with the inspection unit 70. However, it is only necessary that the head unit 60 and the inspection unit 70 are relatively movable. . For example, the moving unit 50 may move the inspection unit 70, or the head unit 60 and the inspection unit 70 may be moved together. Further, only the inspection electrode 72 in the inspection unit 70 may be moved. The nozzle inspection is possible if the inspection electrode 72 and the head 62 are opposed to each other, and in performing the nozzle inspection, the components other than the inspection electrode 72 in the inspection circuit 71 need to be opposed to the head unit 60. Absent.

  In the embodiment described above, the inspection circuit 71 discharges ink from the opposing nozzle toward the inspection electrode 72 in a state where a voltage is applied between the inspection electrode 72 and the nozzle plate 63 facing each other. In the noise inspection period in which ink is not ejected, the presence or absence of ejection or the presence or absence of noise is inspected by detecting an electrical change, but the head unit 60 is inspected for the presence or absence of ejection from the nozzle. For example, any inspection circuit 71 may be used. For example, it is good also as what does not test | inspect the presence or absence of noise. Moreover, it is good also as a test | inspection circuit what is the cap formed with the member which the upper part opened, and was provided with the light emitting element which emits a laser beam, and the incident light receiving element. In this case, it is only necessary to detect whether or not the ink is ejected by detecting whether or not the laser beam is blocked by the ejection of the ink from the nozzle facing this inspection circuit. Furthermore, a detection circuit that detects the presence or absence of ink ejection based on the presence or absence of a pressure change when the liquid ejected from the opposing nozzle has landed may be used. As described above, even when the inspection circuit is for inspecting the presence / absence of ejection by a method other than the present embodiment, a plurality of inspection circuits are provided, and the head unit and the inspection circuit are relatively arranged when any of the inspection circuits is abnormal. If the nozzles are moved and inspected for non-inspected nozzles by an inspection circuit having no abnormality, nozzle inspection can be performed efficiently as in the present embodiment.

  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 embodiment described above, an example in which the liquid ejection apparatus of the present invention is embodied in the ink jet printer 10 has been described. However, a liquid (dispersion) in which particles of liquid other than ink or functional material are dispersed, 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 ejecting apparatus 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, and a liquid material in which the material is dispersed is ejected. 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, 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, 71 inspection circuit, 71A to 71H 1st to 8th inspection circuit 72 inspection electrodes, 72A to 72H first to eighth inspection electrodes, 73 first limiting resistor, 74 high voltage power supply, 75 second limiting resistor, 76 detection control unit, 77 amplifier, 78 inspection capacitor, 79 smoothing capacitor

Claims (6)

A head unit comprising a first nozzle group and a second nozzle group comprising a plurality of nozzles for discharging liquid;
An inspection unit including a first inspection unit and a second inspection unit that inspects the presence or absence of ejection from the nozzle opposite to the head unit;
Moving means for relatively moving the head unit and the inspection unit;
The moving means is controlled so that the first nozzle group and the first inspection section face each other, and the second nozzle group and the second inspection section face each other, and the liquid from the nozzles of the first nozzle group sequentially. Based on the inspection result of the first inspection unit when the liquid is discharged, the quality of discharge of the nozzle is determined, and the inspection of the second inspection unit when the liquid is sequentially discharged from the nozzles of the second nozzle group Processing means for performing discharge determination for determining whether the discharge of the nozzle is good or not based on the result;
With
In performing the discharge determination, the processing means, when an abnormal condition that can be regarded as abnormal in the first inspection unit is satisfied, at least of uninspected nozzles that have not determined whether the discharge is good or not in the first nozzle group. The moving means is controlled so that a part and the second inspection section are opposed to each other, and liquids are sequentially discharged from the nozzles of the first nozzle group that are not inspected facing the second inspection section. Determining whether the discharge of the nozzle is good or not based on the inspection result of the second inspection unit when
Liquid ejection device. When the condition that the processing unit can assume that the first inspection unit cannot inspect the presence / absence of ejection is satisfied as the abnormal condition, the uninspected nozzle of the first nozzle group and the second inspection unit face each other. And controlling the moving means to determine whether or not the non-inspected nozzles are discharged based on the inspection result of the second inspection unit when the liquid is sequentially discharged from the uninspected nozzles. Determining whether or not the uninspected nozzle is discharged is based on the inspection result of the second inspection unit,
The liquid ejection device according to claim 1. In the state where the first nozzle group and the first inspection unit are opposed to each other and the second nozzle group and the second inspection unit are opposed to each other, the processing unit is configured to determine whether or not ejection is performed by the first inspection unit as the abnormal condition. Can be inspected, but when the condition that it can be considered that the completion of the ejection quality determination of all the nozzles of the first nozzle group is delayed as compared with the second nozzle group is satisfied, the uninspected nozzles of the second nozzle group are In a range that does not deviate from the position facing the second inspection section, at least a part of the uninspected nozzles of the first nozzle group faces the second inspection section and the rest faces the first inspection section. The moving means is controlled so that the uninspected nozzles facing the second inspection unit in the first nozzle group and the uninspected nozzles of the second nozzle group are sequentially ejected from the nozzles. 2 Inspection department inspection Based on the result, whether the discharge of the nozzle is good or not is determined, and for the uninspected nozzle that faces the first inspection section in the first nozzle group, the first inspection section when liquid is sequentially discharged from the nozzle Determining the quality of the discharge of the nozzle based on the inspection result of
The liquid ejection device according to claim 1 or 2. The head unit has a first electrode in contact with the liquid,
Each of the first inspection unit and the second inspection unit has a second electrode that can be opposed to the first electrode, and the first electrode and the second electrode are opposed to each other, and a voltage is applied between both electrodes. In a noise inspection period in which an electrical change between both electrodes is detected in a discharge inspection period in which liquid is discharged from the opposing nozzle toward the second electrode in a state where the liquid is applied, and liquid is not discharged from all of the opposing nozzles. An operation for detecting an electrical change between both electrodes is performed for each of the opposing nozzles, and for each nozzle, the presence or absence of ejection and the presence or absence of noise are inspected based on a signal relating to the electrical change,
The processing means determines the quality of nozzle ejection based on the presence or absence of ejection and the presence or absence of noise as the inspection results, and determines whether or not the abnormal condition is successful based on an electrical change between the electrodes during the noise inspection period. judge,
The liquid ejection apparatus according to claim 2. A head unit having a first nozzle group and a second nozzle group each composed of a plurality of nozzles that eject liquid, and a first inspection unit and a second inspection unit that inspect the presence or absence of ejection from the nozzles facing the head unit. A nozzle inspection method for a liquid ejection apparatus, comprising: an inspection unit including: a moving unit that relatively moves the head unit and the inspection unit;
The moving means is controlled so that the first nozzle group and the first inspection section face each other, and the second nozzle group and the second inspection section face each other, and the liquid from the nozzles of the first nozzle group sequentially. Based on the inspection result of the first inspection unit when the liquid is discharged, the quality of discharge of the nozzle is determined, and the inspection of the second inspection unit when the liquid is sequentially discharged from the nozzles of the second nozzle group In performing the discharge determination for determining whether or not the nozzle is discharged based on the result, when an abnormal condition that can be considered that the first inspection unit is abnormal is satisfied, the discharge quality of the first nozzle group is determined. The moving means is controlled so that at least a part of uninspected nozzles and the second inspection part face each other, and the uninspected nozzles that face the second inspection part in the first nozzle group Discharges liquid sequentially from the nozzle Determining the quality of the discharge of the nozzle on the basis of the second inspection unit of the inspection results obtained while,
Nozzle inspection method including:   A program for causing one or more computers to realize the nozzle inspection method according to claim 5.