Liquid dispensing device

Abstract

To reduce maintenance time for recovering an anomalous nozzle difficult to recover.SOLUTION: A control device of a printer executes a setting process for selectively setting a first mode in which inspection drive for performing an inspection process is performed and a determination whether the number of anomalous nozzles is equal to or larger than a threshold or not is made or a second mode in which the inspection drive is not performed. In addition, when a state in which the number of anomalous nozzles is equal to or larger than the threshold continues for three days while the first mode has been set, the control device sets the second mode in the setting process.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a liquid ejection device that ejects liquid from a nozzle. [Background technology]

[0002] As an example of a liquid ejection device that ejects liquid from nozzles, Patent Document 1 describes a printer that ejects ink from multiple nozzles to record an image. When there is a print job, the printer described in Patent Document 1 performs a nozzle inspection in which ink is ejected from each nozzle of the print head to determine whether or not there is a defective ejection nozzle (abnormal nozzle) that does not eject ink normally. If there is a defective ejection nozzle, cleaning is performed, which is a process of sucking ink from the nozzle. After cleaning, the nozzle inspection is performed again, and cleaning is repeated until there are no defective ejection nozzles or the number of cleanings reaches a predetermined number. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-214869 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the printer described in Patent Document 1, for example, if there is a scratch on the nozzle surface on which the multiple nozzles of the print head are formed, the nozzle that has become defective in ejection due to the scratch is repeatedly cleaned. However, in this case, cleaning does not resolve the ejection failure of that nozzle. In other words, maintenance time is wasted.

[0005] SUMMARY OF THE PRESENTLY PREFERRED EMBODIMENTS An object of the present invention is to provide a liquid ejection device that is capable of reducing the maintenance time required to restore abnormal nozzles that are difficult to restore. [Means for solving the problem]

[0007] Books The liquid ejection device of the present invention is 1 According to the above viewpoint, a liquid ejection head having a plurality of nozzles for ejecting liquid, Notes When the liquid ejection head is driven for inspection to check whether the nozzle is an abnormal nozzle having an abnormality in ejecting liquid, Notes The control device is equipped with a signal output unit that outputs a determination signal indicating whether or not a nozzle is an abnormal nozzle, recovery means that performs a recovery operation to discharge liquid from the nozzle, and a control device. The control device can execute a setting process to selectively set between a first mode in which the control device performs the inspection drive and causes the recovery means to perform the recovery operation after it is determined that the number of abnormal nozzles is equal to or greater than a threshold based on the determination signal transmitted from the signal output unit, and a second mode in which the control device performs the inspection drive and does not cause the recovery means to perform the recovery operation even after it is determined that the number of abnormal nozzles is equal to or greater than a threshold based on the determination signal transmitted from the signal output unit, and if the number of abnormal nozzles continues to be equal to or greater than the threshold for a second predetermined period while the first mode is set in the setting process, the control device can execute a setting process to selectively set between a first mode in which the control device performs the inspection drive and causes the recovery means to perform the recovery operation after it is determined that the number of abnormal nozzles is equal to or greater than a threshold based on the determination signal transmitted from the signal output unit, and When the second mode is set in the setting process, if it is determined that the number of abnormal nozzles is less than the threshold value, the first mode is set in the setting process. do.

[0009] The liquid ejection device of the present invention is 2 According to the above viewpoint, a liquid ejection head having a plurality of nozzles for ejecting liquid, Notes When the liquid ejection head is driven for inspection to check whether the nozzle is an abnormal nozzle having an abnormality in ejecting liquid, NotesThe control device is equipped with a signal output unit that outputs a determination signal indicating whether or not a nozzle is an abnormal nozzle, recovery means that performs a recovery operation to discharge liquid from the nozzle, and a control device. The control device can execute a setting process to selectively set between a first mode in which the control device performs the inspection drive and causes the recovery means to perform the recovery operation after it is determined that the number of abnormal nozzles is equal to or greater than a threshold based on the determination signal transmitted from the signal output unit, and a second mode in which the control device performs the inspection drive and does not cause the recovery means to perform the recovery operation even after it is determined that the number of abnormal nozzles is equal to or greater than a threshold based on the determination signal transmitted from the signal output unit, and when the first mode is set in the setting process, if the number of abnormal nozzles continues to be equal to or greater than the threshold while the recovery operation is performed a second predetermined number of times, the control device can execute a setting process to selectively set between a first mode in which the control device performs the inspection drive and causes the recovery means to perform the recovery operation after it is determined that the number of abnormal nozzles is equal to or greater than a threshold based on the determination signal transmitted from the signal output unit, and a second mode in which the control device performs the inspection drive and causes the recovery means not to perform the recovery operation When the second mode is set in the setting process, if it is determined that the number of abnormal nozzles is less than the threshold value, the first mode is set in the setting process. do.

[0010] The liquid ejection device of the present invention is 3 According to the above viewpoint, a liquid ejection head having a plurality of nozzles for ejecting liquid, Notes When the liquid ejection head is driven for inspection to check whether the nozzle is an abnormal nozzle having an abnormality in ejecting liquid, Notes The control device is equipped with a signal output unit that outputs a determination signal indicating whether or not a nozzle is the abnormal nozzle, and a control device. The control device can execute a setting process to selectively set a first mode in which the inspection drive is performed and a determination is made as to whether or not the number of abnormal nozzles is equal to or greater than a threshold based on the determination signal transmitted from the signal output unit when at least one of a first condition and a second condition different from the first condition is satisfied, and a second mode in which the inspection drive is not performed only when the second condition of the first condition and the second condition is satisfied, and if a state in which the number of abnormal nozzles is equal to or greater than the threshold continues for a first predetermined period while the first mode is set in the setting process, the control device can execute a setting process to selectively set a first mode in which the inspection drive is performed and a determination is made as to whether or not the number of abnormal nozzles is equal to or greater than a threshold based on the determination signal transmitted from the signal output unit when at least one of a first condition and a second condition different from the first condition is satisfied, and In the second mode, the inspection driving is performed only once when the first condition is satisfied during the period of the second mode. . According to a fourth aspect, a liquid ejection device of the present invention includes a liquid ejection head having a plurality of nozzles that eject liquid, a signal output unit that outputs a determination signal indicating whether or not the nozzle is an abnormal nozzle when the liquid ejection head is caused to perform an inspection drive for checking whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid, a clock unit that outputs a time signal indicating the time, and a control device, and the control device switches between a first mode in which the inspection drive is performed every day when a time signal indicating a predetermined time output from the clock unit is received, and a second mode in which the inspection drive is not performed even when a time signal indicating the predetermined time output from the clock unit is received every day. Effect of the Invention

[0011] According to a first aspect of the liquid ejection device of the present invention, , No. 2 If the number of abnormal nozzles continues to be equal to or greater than the threshold value for a certain period of time, the abnormal nozzles are often nozzles that are difficult to recover. Then, by switching from the first mode to the second mode, recovery operations are not performed. This makes it possible to reduce the maintenance time required for recovery operations to recover abnormal nozzles that are difficult to recover. 。 The liquid ejection device of the present invention is 2 From this viewpoint, if the number of abnormal nozzles remains equal to or greater than the threshold value while the recovery operation is being performed the second predetermined number of times, the abnormal nozzles are often nozzles that are difficult to recover. Then, by switching from the first mode to the second mode, the recovery operation is not performed. This makes it possible to reduce the maintenance time required for the recovery operation to recover abnormal nozzles that are difficult to recover. The liquid ejection device of the present invention is 3 From this viewpoint, if the number of abnormal nozzles continues to be equal to or greater than the threshold value during the first predetermined period, the abnormal nozzles are often nozzles that are difficult to recover. Then, by switching from the first mode to the second mode, the inspection drive is not performed only when the second condition is satisfied. This makes it possible to reduce the maintenance time required for the inspection drive. According to a fourth aspect of the liquid ejection device of the present invention, it is possible to switch between a first mode in which the inspection drive is performed at a predetermined time every day and a second mode in which the inspection drive is not performed even at the predetermined time every day, thereby reducing the maintenance time required for the inspection drive. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic configuration diagram of a printer according to a first embodiment of the present invention. [Diagram 2] 4A and 4B are diagrams for explaining detection electrodes disposed in a cap, and the connection relationship between the detection electrodes and a high-voltage power supply circuit and a determination circuit. [Diagram 3] FIG. 1A is a diagram showing the change in voltage value of the detection electrode when ink is ejected from the nozzle, and FIG. 1B is a diagram showing the change in voltage value of the detection electrode when ink is not ejected from the nozzle. [Figure 4]FIG. 2 is a block diagram showing the electrical configuration of the printer. [Diagram 5] 10 is a flowchart showing an operation of the printer from a standby state. [Figure 6] 6 is a flowchart showing a flow of the first mode process shown in FIG. 5. [Figure 7] 6 is a flowchart showing a flow of the second mode process shown in FIG. 5. [Figure 8] 10 is a flowchart showing an operation from a standby state of a printer according to a second embodiment of the present invention. [Figure 9] 13 is a flowchart showing a flow of a second mode process of a printer according to a third embodiment of the present invention. [Figure 10] 13 is a flowchart showing an operation from a standby state of a printer according to a fourth embodiment of the present invention. [Figure 11] 13 is a flowchart showing a flow of a second mode process of a printer according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Preferred embodiments of the present invention will now be described.

[0014] <Overall printer configuration> As shown in FIG. 1, the printer 1 (the "liquid ejection device" of the present invention) according to the first embodiment includes a carriage 2, a subtank 3, an inkjet head 4 (the "liquid ejection head" of the present invention), a platen 5, transport rollers 6 and 7, a maintenance unit 8, etc.

[0015] The carriage 2 is supported by two guide rails 11, 12 extending in the scanning direction. The carriage 2 is connected to a carriage motor 86 (see FIG. 4) via a belt (not shown) or the like, and when the carriage motor 86 is driven, the carriage 2 moves in the scanning direction along the guide rails 11, 12. In the following description, the right and left sides of the scanning direction are defined as shown in FIG. 1.

[0016] The subtank 3 is mounted on the carriage 2. Here, the printer 1 includes a cartridge holder 13, in which four ink cartridges 14 are removably attached. The four ink cartridges 14 are aligned in the scanning direction, and from the one arranged on the right side in the scanning direction, they store black, yellow, cyan, and magenta inks ("liquid" of the present invention). The subtank 3 is connected to the four ink cartridges 14 attached to the cartridge holder 13 via four tubes 15. In this way, the four colors of ink are supplied to the subtank 3 from the four ink cartridges 14.

[0017] The inkjet head 4 is mounted on the carriage 2 and connected to the lower end of the subtank 3. The inkjet head 4 is supplied with the four colors of ink from the subtank 3. The inkjet head 4 ejects ink from a plurality of nozzles 10 formed on its lower surface, a nozzle face 4a. More specifically, the nozzles 10 are arranged in a transport direction perpendicular to the scanning direction to form a nozzle row 9, and on the nozzle face 4a, four nozzle rows 9 are lined up in the scanning direction. From the nozzles 10, black, yellow, cyan, and magenta inks are ejected starting from the nozzle row 9 on the right side of the scanning direction.

[0018] The platen 5 is disposed below the inkjet head 4 and faces the multiple nozzles 10. The platen 5 extends over the entire length of the recording paper P (the "ejection receiving medium" of the present invention) in the scanning direction and supports the recording paper P from below. The transport roller 6 is disposed upstream of the inkjet head 4 and the platen 5 in the transport direction. The transport roller 7 is disposed downstream of the inkjet head 4 and the platen 5 in the transport direction. The transport rollers 6 and 7 are connected to a transport motor 87 (see FIG. 4) via gears and the like (not shown). When the transport motor 87 is driven, the transport rollers 6 and 7 rotate and the recording paper P is transported in the transport direction.

[0019] The maintenance unit 8 includes a cap 71, a suction pump 72, and a waste liquid tank 73. The cap 71 is disposed to the right of the platen 5 in the scanning direction. When the carriage 2 is positioned at a maintenance position to the right of the platen 5 in the scanning direction, the multiple nozzles 10 face the cap 71.

[0020] The cap 71 can be raised and lowered by a cap lifting mechanism 88 (see FIG. 4). When the carriage 2 is positioned at the maintenance position so that the plurality of nozzles 10 and the cap 71 face each other, the cap 71 is raised by the cap lifting mechanism 88, whereby the upper end of the cap 71 comes into close contact with the nozzle surface 4a, and the plurality of nozzles 10 are covered by the cap 71. Note that the cap 71 is not limited to covering the plurality of nozzles 10 by coming into close contact with the nozzle surface 4a. The cap 71 may cover the plurality of nozzles 10 by coming into close contact with a frame (not shown) or the like that is arranged around the nozzle surface 4a of the inkjet head 4, for example.

[0021] The suction pump 72 is a tube pump or the like, and is connected to the cap 71 and the waste liquid tank 73. In the maintenance unit 8, when the suction pump 72 is driven with the plurality of nozzles 10 covered with the cap 71 as described above, it is possible to perform a so-called suction purge (recovery operation) in which ink is discharged from inside the inkjet head 4 through the plurality of nozzles 10. The ink discharged by the suction purge is stored in the waste liquid tank 73.

[0022] For convenience, the cap 71 covers all the nozzles 10 together, and ink in the inkjet head 4 is discharged from all the nozzles 10 during suction purge. However, the present invention is not limited to this. For example, the cap 71 may have a portion covering the nozzles 10 constituting the rightmost nozzle row 9 that ejects black ink and a portion covering the nozzles 10 constituting the three leftmost nozzle rows 9 that eject color inks (yellow, cyan, and magenta inks), and may selectively discharge either the black ink or the color ink in the inkjet head 4 during suction purge. Alternatively, for example, the cap 71 may be provided for each nozzle row 9, and ink may be discharged from the nozzles 10 for each nozzle row 9 separately during suction purge.

[0023] As shown in FIG. 2, a detection electrode 76 having a rectangular planar shape is disposed within the cap 71. The detection electrode 76 is connected to a high-voltage power supply circuit 77 via a resistor 79. A predetermined positive potential (for example, about 600 V) is applied to the detection electrode 76 by the high-voltage power supply circuit 77 during the inspection drive described below. Meanwhile, the inkjet head 4 is held at the ground potential. This generates a predetermined potential difference between the inkjet head 4 and the detection electrode 76. A determination circuit 78 is connected to the detection electrode 76. The determination circuit 78 compares the potential of the signal output from the detection electrode 76 with a threshold value Vt, and outputs a signal according to the result.

[0024] More specifically, since there is a potential difference between the inkjet head 4 and the detection electrode 76, the ink ejected from the nozzle 10 is charged. When the carriage 2 is positioned at the maintenance position and ink is ejected from the nozzle 10 toward the detection electrode 76, as shown in Fig. 3(a), the charged ink approaches the detection electrode 76, and until the ink lands on the detection electrode 76, the potential of the detection electrode 76 decreases from the potential Va when the inkjet head 4 is not driven and reaches a potential Vb lower than the potential Va. Then, after the charged ink lands on the detection electrode 76, the potential of the detection electrode 76 gradually rises and returns to the potential Va. That is, during the driving period Td of the inkjet head 4, the potential of the detection electrode 76 changes.

[0025] On the other hand, when no ink is ejected from the nozzle 10, as shown in Fig. 3(b), during the driving period Td of the inkjet head 4, the potential of the detection electrode 76 hardly changes from the potential Va. Therefore, a threshold value Vt (Va < Vt < Vb) is set in the determination circuit 78 to distinguish between these cases. Then, the determination circuit 78 compares the maximum potential of the voltage signal output from the detection electrode 76 with the threshold value Vt during the driving period Td of the inkjet head 4 and outputs a determination signal according to the determination result. In this embodiment, the combination of the detection electrode 76, the high-voltage power supply circuit 77, the resistor 79, and the determination circuit 78 corresponds to the "signal output unit" of the present invention. And this signal output unit outputs a determination signal according to whether the nozzle 10 is an abnormal nozzle from which no ink is ejected.

[0026] Further, here, a positive potential is applied to the detection electrode 76 by the high-voltage power supply circuit 77, but a negative potential (for example, about -600 V) may be applied to the detection electrode 76 by the high-voltage power supply circuit 77. In this case, contrary to the above, when ink is ejected from the nozzle 10 toward the detection electrode 76 with the carriage 2 positioned at the maintenance position, the charged ink approaches the detection electrode 76, and the potential of the detection electrode 76 rises from the potential Va until the ink lands on the detection electrode 76, and after the ink lands on the detection electrode 76, the potential of the detection electrode 76 gradually decreases and returns to the potential Va.

[0027] <Printer electrical configuration> Next, the electrical configuration of the printer 1 will be described. As shown in FIG. 4, the printer 1 has a control device 80. The control device 80 is composed of a central processing unit (CPU) 81, a read only memory (ROM) 82, a random access memory (RAM) 83, a flash memory 84, an application specific integrated circuit (ASIC) 85, and the like. The control device 80 controls the operations of a carriage motor 86, an inkjet head 4, a conveying motor 87, a cap lifting mechanism 88, a suction pump 72, a high voltage power supply circuit 77, a driver IC 89, and the like. In this embodiment, the control device 80 controls the driver IC 89 to control the inkjet head 4. A determination signal is also input to the control device 80 from a determination circuit 78.

[0028] In addition to the components described above, the printer 1 also has a display unit 69, an operation unit 70, a clock unit 68, and a battery 66. The display unit 69 is, for example, a liquid crystal display provided on the housing of the printer 1. The control device 80 controls the display unit 69 to display information necessary for the operation of the printer 1. The operation unit 70 is, for example, buttons provided on the housing of the printer 1, a touch panel provided on the display unit 69, etc. A user can input signals to the control device 80 by operating the operation unit 70.

[0029] In this embodiment, the operation unit 70 includes a power switch (not shown). The user can turn the printer 1 on and off by operating the power switch. When the user operates the power switch on the operation unit 70 to turn on the printer 1, a power-on signal indicating that the printer 1 has been turned on is output from the operation unit 70, and the control device 80 receives this power-on signal.

[0030] The clock unit 68 keeps time, and the control device 80 receives a time signal indicating the time (the "test signal" of the present invention) from the clock unit 68. The battery 66 is connected to at least the control device 80 and the clock unit 68. Power is supplied to the printer 1 from an outlet (not shown), and the battery 66 is charged at this time. When the printer 1 is unplugged, power is supplied from the battery 66 to at least the control device 80 and the clock unit 68.

[0031] The control device 80 may be one in which only the CPU 81 performs various processes, one in which only the ASIC 85 performs various processes, or one in which the CPU 81 and the ASIC 85 work together to perform various processes. The control device 80 may be one in which one CPU 81 performs processes independently, or one in which multiple CPUs 81 share the processes. The control device 80 may be one in which one ASIC 85 performs processes independently, or one in which multiple ASICs 85 share the processes.

[0032] <Control from standby state> Next, the control by the control device 80 showing the operation from the standby state in the printer 1 will be described. In the printer 1, during the above-mentioned standby state, the control device 80 performs processing according to the flow in Fig. 5. Here, the flow in Fig. 5 continues while power is being supplied to the control device 80 and the clock unit 68 from the outlet or the battery 66.

[0033] To explain the flow of Figure 5 in more detail, the control device 80 waits until the time signal received from the clock unit 68 does not indicate that it is the specified time (S101: NO), until the specified period of time has not elapsed since the previous inspection process (described later) (S102: NO), and until the control device 80 has received a recording command signal (described later) (S103: NO).

[0034] Here, the specified period is a period for periodically performing the inspection process described below, and in S102, the control device 80 determines whether or not the specified period has elapsed since the previous inspection process based on the time signal from the clock unit 68 and the inspection history information described below.

[0035] Furthermore, when the time signal received from the clock unit 68 (the "test signal" of the present invention) indicates that it is the predetermined time (S101: YES), the control device 80 proceeds to S104. The predetermined time in this embodiment is set early in the morning, such as 6:00 AM, but is not particularly limited thereto.

[0036] Also, when a predetermined period of time has passed since the previous inspection process (S102: YES), the control device 80 proceeds to S104. At this time, the control device 80 stores inspection flag information for executing the inspection process in the flash memory 84. When a predetermined period of time has passed since the previous inspection process, the viscosity of the ink in the nozzle 10 may change, and the state of whether or not the nozzle is abnormal may change. Therefore, in this embodiment, when a predetermined period of time has passed since the previous inspection process, an inspection drive is performed. This makes it possible to accurately identify abnormal nozzles.

[0037] Furthermore, when a recording command signal for recording on the recording paper P in the printer 1 is received (S103: YES), the control device 80 proceeds to S104. The recording command signal is a signal that instructs the printer 1 to record on the recording paper P, and is transmitted to the control device 80 from an external device or the like.

[0038] The control device 80 judges whether or not the second mode flag information for setting the second mode is stored in the flash memory 84 (S104). If the first mode flag information for setting the first mode is stored in the flash memory 84 (S104: NO), the control device 80 judges whether or not the abnormal flag information has been continuously stored for three days (the "first predetermined period" of the present invention) (S105). In S105, the control device 80 judges whether or not the abnormal flag information has been continuously stored for three days based on the time signal from the clock unit 68 and the inspection history information, which will be described later, linked to the stored abnormal flag information. The first mode refers to a mode in which the first mode process, which will be described later, is executed, and the second mode refers to a mode in which the second mode process, which will be described later, is executed. The abnormal flag information is flag information stored in the flash memory 84 when the number of abnormal nozzles, in which the nozzle 10 is an abnormal nozzle, is equal to or greater than a threshold value in the inspection process, which will be described later.

[0039] If no abnormality flag information is stored in the flash memory 84, or if abnormality flag information is stored but has not been continuously stored for more than three days (S105: NO), the process proceeds to the first mode processing (S106).

[0040] If the abnormality flag information has been stored in the flash memory 84 continuously for three days or more (S105: YES), the first mode is changed to the second mode (S107: "setting process" of the present invention). At this time, the control device 80 updates the mode flag information stored in the flash memory 84 to the second mode flag information. The second mode flag information also includes updated time information. After this, the process proceeds to the second mode process (S108).

[0041] In S104, if second mode flag information is stored in the flash memory 84 (S104: YES), the control device 80 determines whether the setting period of the second mode has passed three days (the "third predetermined period" of the present invention) (S109). In S109, the control device 80 determines whether three days have passed since the second mode flag information was stored in the flash memory 84, based on the time signal from the clock unit 68 and the second mode flag information. Note that, although the setting period of the second mode is three days in this embodiment, this may be changed as appropriate and is not particularly limited.

[0042] If the second mode flag information has not been continuously stored in the flash memory 84 for three days (S109: NO), the process proceeds to the second mode process (S108).

[0043] If the second mode flag information has been stored in the flash memory 84 continuously for three days (S109: YES), the second mode is set to the first mode (S110: "setting process" of the present invention). At this time, the control device 80 updates the mode flag information stored in the flash memory 84 to the first mode flag information. After this, the process proceeds to the first mode process (S106).

[0044] In the above-described embodiment, after proceeding from S101 to S103 to S104, S105, S107, S109, and S110 are executed, but these S105, S107, S109, and S110 may be processed independently in a dedicated flow as needed or periodically to perform a setting process for setting either the first or second mode.

[0045] <First mode processing> Next, the first mode process will be described. As shown in Fig. 6, in the first mode process, the control device 80 first judges whether the received signal is a recording command signal (S201). If the control device 80 receives a time signal indicating that it is a predetermined time or if the check flag information is stored in the flash memory 84 (S201: NO), it executes the check process (S202).

[0046] In the inspection process, the control device 80 transmits a drive signal to the driver IC 89 to perform an inspection drive that drives the inkjet head 4 to eject ink from each of the multiple nozzles 10 in order. At this time, the control device 80 stores inspection history information, which is information on the time when the inspection drive was performed, in the flash memory 84 based on a time signal from the clock unit 68. Then, the control device 80 stores all of the nozzles 10 that are abnormal among the multiple nozzles 10 in the flash memory 84 based on a judgment signal output from the judgment circuit 78 for each nozzle 10 during the inspection drive. In other words, the control device 80 updates the information of the nozzle 10 that was previously abnormal stored in the flash memory 84 to the information of the nozzle 10 that is currently abnormal. At this time, if inspection flag information is stored in the flash memory 84, the control device 80 erases the inspection flag information.

[0047] The control device 80 determines whether the number of abnormal nozzles stored in the flash memory 84 is equal to or greater than a threshold value (S203). If the number of nozzles 10 stored in the flash memory 84 is equal to or greater than the threshold value (S203: YES), the control device 80 stores recovery flag information in the flash memory 84 (S204). Note that the recovery flag information is flag information that is stored in the flash memory 84 in order to later perform suction purge to recover from the abnormality of the nozzles 10 when the number of abnormal nozzles, in which the nozzles 10 are abnormal, is equal to or greater than a threshold value in the inspection process.

[0048] The control device 80 stores the abnormality flag information in the flash memory 84 (S205). At this time, the control device 80 associates the stored abnormality flag information with the time information of the inspection drive in the inspection process corresponding to the abnormality flag information. This makes it possible to know the elapsed time since the abnormality flag information was stored in S105. Note that even if abnormality flag information based on the inspection drive before the current inspection drive is stored in the flash memory 84, the abnormality flag information in the current inspection drive is stored in the flash memory 84. In this way, the first mode processing ends.

[0049] In S203, if the number of abnormal nozzles stored in the flash memory 84 is less than the threshold value (S203: NO), the control device 80 erases the abnormal flag information if abnormal flag information is stored in the flash memory 84 (S206). At this time, the control device 80 resets the variable C, which is the number of times the recovery process has been performed, to 0, and erases the recovery flag information if recovery flag information is stored in the flash memory 84. In this way, the first mode process ends.

[0050] In S201, if the received signal is a recording command signal (S201: YES), the control device 80 judges whether the inspection process has been performed during one day based on the time signal from the clock unit 68 and the inspection history information stored in the flash memory 84 (S207). In this embodiment, one day refers to a period from 0:00 AM to 0:00 AM of the next day, but the start time and end time may be set appropriately as long as it is 24 hours. In this embodiment, the control device 80 judges in S207 whether the inspection history information indicates that the inspection process has been performed at least once between 0:00 AM and a predetermined time (6:00 AM).

[0051] If the inspection process has never been executed (S207: NO), the control device 80 executes an inspection process similar to S202 (S208). After that, the control device 80 executes S209 to S212 similar to S203 to S206.

[0052] If the inspection process has been executed at least once (S207: YES), the control device 80 determines whether recovery flag information is stored in the flash memory 84 (S213).

[0053] After S211, and if recovery flag information is stored in the flash memory 84 in S213 (S213: YES), the control device 80 executes recovery processing (S214).

[0054] In the recovery process in this embodiment, the control device 80 causes a suction purge to be performed. After the suction purge is completed, the control device 80 erases the recovery flag information stored in the flash memory 84.

[0055] After S212 and S214, and if recovery flag information is not stored in the flash memory 84 in S213 (S213: NO), the control device 80 executes a print process (S215). That is, the control device 80 controls the paper feed mechanism (not shown) and the transport motor 87 based on the recording command signal to cause the paper feed mechanism to supply the recording paper P, and causes the transport rollers 6 and 7 to transport the recording paper P to a position where an area on the recording paper P where an image is to be recorded in the first recording pass faces the multiple nozzles 10 of the inkjet head 4. The control device 80 then controls the carriage motor 86 to move the carriage 2 in the scanning direction, while controlling the driver IC 89 to drive multiple drive elements, thereby causing the inkjet head 4 to perform a recording pass in which ink is ejected from the multiple nozzles 10 toward the recording paper P.

[0056] Thereafter, if recording on one sheet of recording paper P is not complete, the control device 80 controls the conveying motor 87 to cause the conveying rollers 6, 7 to convey the recording paper P a predetermined distance, and repeats the operation of causing the conveying rollers 6, 7 to perform a recording pass again until recording on one sheet of recording paper P is complete. If recording of an image on one sheet of recording paper P is complete, the control device 80 controls the conveying motor 87 to cause the conveying rollers 6, 7 to discharge the recording paper P on which recording has been completed. In this manner, the first mode process ends. Note that, as a modified example, S207 and S213 in the first mode process do not have to be executed.

[0057] <Second mode processing> Next, the second mode process will be described. As shown in Fig. 7, in the second mode process, the control device 80 first judges whether the received signal is a recording command signal (S301). If a time signal indicating that it is a predetermined time has been received, or if check flag information is stored in the flash memory 84 (S301: NO), the second mode process ends. At this time, if check flag information is stored in the flash memory 84, the control device 80 erases the check flag information.

[0058] In S301, if the received signal is a recording command signal (S301: YES), the control device 80 determines whether recovery flag information is stored in the flash memory 84 (S302), similar to S213. Then, S303 and S304, similar to S214 and S215 described above, are performed. In this manner, the second mode process ends.

[0059] As a modified example, in the second mode process, the process may proceed from S301 to S302, and the print process may be executed without executing the recovery process even if the recovery flag information is stored in the flash memory 84. This makes it possible to omit the maintenance time required for executing the recovery process. As a result, the time from receiving the recording command signal to starting the print process is shortened. Also, since the recovery process is not executed, the consumption of ink can be reduced.

[0060] As described above, according to the printer 1 of this embodiment, if the period during which the abnormality flag information has been stored in the flash memory 84 (i.e., the period during which the number of abnormal nozzles continues to be equal to or greater than the threshold) has passed three days (first predetermined period), the abnormal nozzle is often a nozzle that is difficult to recover. In this case (S105: YES), in S107, the control device 80 sets the mode from the first mode to the second mode. Therefore, even if the process proceeds to the second mode through S101 to S103, the test drive is not performed. Therefore, since the test process using the test drive is not performed, the maintenance time can be reduced. Furthermore, since the test drive is not performed, the consumption of ink can also be reduced.

[0061] Furthermore, when the second mode setting period (period during which the second mode flag information is stored) has elapsed for three days (a third predetermined period) in S109, the control device 80 sets the first mode in S110. As a result, while the second mode is set, abnormal nozzles may enter a state in which they are more likely to recover due to changes in the environment. In this case, the first mode is set after three days have elapsed, making it possible to perform inspection drive and inspect whether the nozzles have recovered or not.

[0062] Furthermore, the inspection signal that triggers the inspection drive for carrying out the inspection process is a time signal that is output at a predetermined time from the clock unit 68. As a result, upon receiving a signal indicating that it is the predetermined time, the inspection drive is carried out, making it possible to inspect whether the nozzles have recovered or not.

[0063] Furthermore, the test drive executed in the test process drives the nozzle 10 to eject ink. In this way, when testing whether the nozzle 10 is an abnormal nozzle, ink is ejected from the nozzle 10 to determine whether it is an abnormal nozzle, and therefore the accuracy of the determination is improved compared to testing without ejecting ink from the nozzle 10.

[0064] Next, a printer according to the second embodiment will be described below with reference to Fig. 8. The printer according to this embodiment is the same as the printer 1 according to the first embodiment except for S105 and S109 in the operation flow from the standby state. Therefore, the same reference numerals are used for the same parts as the first embodiment, and the description thereof will be omitted.

[0065] <Control from standby state> In the printer of this embodiment, the control device 80 performs processing according to the flow of Fig. 8. The control device 80 performs S401 to S404, which are similar to S101 to S104 described above.

[0066] If first mode flag information is stored in the flash memory 84 (S404: NO), the control device 80 determines whether the number of consecutive times that it has been determined that the number of abnormal nozzles is equal to or greater than the threshold has reached three (the "first predetermined number" of the present invention) (S405). In other words, the control device 80 determines whether the number of consecutive times that it has been determined that the number of abnormal nozzles is equal to or greater than the threshold has reached three, based on the inspection history information and abnormality flag information (time information of the inspection drive) stored in the flash memory 84.

[0067] If the number of consecutive determinations is less than three (S405: NO), the process proceeds to the first mode process similar to S106 described above (S406).

[0068] If the number of consecutive determinations reaches three (S405: YES), the first mode is set to the second mode (S407: "setting process" of the present invention) in the same manner as in S107 described above. After this, the process proceeds to the second mode process (S408) similar to S108 described above.

[0069] In S404, if the second mode flag information is stored in the flash memory 84 (S404: YES), the control device 80 determines whether the number of consecutive times that the number of abnormal nozzles is determined to be equal to or greater than the threshold has reached three (the "third predetermined number" of the present invention) (S409). In other words, the control device 80 executes the same process as S405.

[0070] If the number of consecutive determinations is less than three (S409: NO), the process proceeds to the second mode process (S408).

[0071] If the number of consecutive determinations reaches three (S409: YES), the second mode is set to the first mode (S410: "setting process" of the present invention) in the same manner as in S110 described above. After this, the process proceeds to the first mode process (S406).

[0072] In this embodiment as well, steps S405, S407, S409, and S410 may be independently processed as needed or periodically in a dedicated flow to perform setting processing for setting either the first or second mode.

[0073] As described above, according to the printer of this embodiment, when the number of consecutive times that it is determined that the number of abnormal nozzles is equal to or greater than the threshold reaches three times (first predetermined number of times), the abnormal nozzle is often a nozzle that is difficult to recover. In this case (S405: YES), in S407, the control device 80 sets the mode from the first mode to the second mode. Therefore, even if the process proceeds to the second mode through S401 to S403, the test drive is not performed. Therefore, the test process by the test drive is not performed, and the maintenance time can be reduced. Furthermore, since the test drive is not performed, the consumption of ink can also be reduced.

[0074] Furthermore, when the number of consecutive times in S409 that the number of abnormal nozzles is determined to be equal to or greater than the threshold reaches three (a third predetermined number of times), the first mode is set in S410. As a result, while the second mode is set, the abnormal nozzles may enter a state where they are more likely to recover due to changes in the environment. In this case, when the number of consecutive times that the number of abnormal nozzles is determined to be equal to or greater than the threshold reaches three, the first mode is set, making it possible to perform inspection drive and inspect whether the nozzles have recovered or not.

[0075] Next, a printer according to a third embodiment will be described below with reference to Fig. 9. The printer according to this embodiment is the same as the printer 1 according to the first embodiment except for the second mode processing. Therefore, the same reference numerals are used to indicate the same parts as the first embodiment, and the description thereof will be omitted.

[0076] <Second mode processing> In the printer of this embodiment, the control device 80 performs the second mode process according to the flow of Fig. 9. The control device 80 first determines whether the received signal is a recording command signal (S501), similar to S201 described above. If the control device 80 receives a time signal indicating that it is a predetermined time, or if the check flag information is stored in the flash memory 84 (S501: NO), it executes a check process similar to S202 described above (S502).

[0077] After this, S503 and S504 are executed, which are similar to S203 to S205 described above. In S503, if the number of abnormal nozzles stored in the flash memory 84 is less than the threshold value (S503: NO), the control device 80 erases the abnormal flag information if abnormal flag information is stored in the flash memory 84 (S505). At this time, the control device 80 resets the variable C, which is the number of times the recovery process has been performed, to 0, and erases the recovery flag information if recovery flag information is stored in the flash memory 84. Also, at this time, the control device 80 updates the mode flag information stored in the flash memory 84 to the first mode flag information (the "setting process" of the present invention). In this way, the second mode process is completed.

[0078] In S501, if the received signal is a recording command signal (S501: YES), the control device 80 executes an inspection process similar to S502 (S506). After that, the control device 80 executes S507 to S509 similar to S503 to S505.

[0079] Next, the control device 80 executes a print process similar to S215 described above (S510), thus completing the second mode process.

[0080] As described above, according to the printer of this embodiment, as in the first embodiment described above, if the period during which the abnormality flag information is stored in the flash memory 84 (i.e., the period during which the number of abnormal nozzles continues to be equal to or greater than the threshold) has passed three days (the "second predetermined period" of the present invention), the abnormal nozzle is often a nozzle that is difficult to recover. In this case (S105: YES), in S107, the control device 80 sets the mode from the first mode to the second mode. In this embodiment, if the process proceeds to the second mode process through S101 to S103, even if the inspection drive is performed, the recovery process (recovery operation: suction purge) is not performed. Therefore, the recovery process for recovering the abnormal nozzle that is difficult to recover is not performed, so the maintenance time can be reduced. In addition, since the recovery process is not performed, the consumption of ink can also be suppressed. Note that the same effects can be obtained in a configuration similar to each of the above-mentioned embodiments.

[0081] Furthermore, if it is determined that the number of abnormal nozzles is less than the threshold value when the second mode process is set (S503: NO, S507: NO), the control device 80 sets the first mode in S505 and S509. As a result, while the second mode is set, the number of abnormal nozzles may become less than the threshold value, making it easier for the abnormal nozzles to recover. In this case, the first mode is set, making it possible to perform inspection drive and to inspect whether the nozzles have recovered or not.

[0082] Next, a printer according to the fourth embodiment will be described below with reference to Fig. 10. The printer in this embodiment is the same as the printer in the third embodiment except for steps S105 and S109 during standby. Therefore, the same reference numerals are used to indicate the same parts as the third embodiment, and the description thereof will be omitted.

[0083] <Control from standby state> In the printer of this embodiment, the control device 80 performs processing according to the flow of Fig. 10. The control device 80 performs S601 to S604, which are similar to S101 to S104 described above.

[0084] If first mode flag information is stored in the flash memory 84 (S604: NO), the control device 80 determines whether the number of abnormal nozzles remains equal to or greater than the threshold value while the recovery process is performed three times (the "second predetermined number" of the present invention) (S605). In this embodiment, when abnormality flag information is stored in the flash memory 84, recovery flag information for executing the recovery process is stored, and when the abnormality flag information is erased, the number of recovery processes is reset. Thus, the control device 80 determines whether the number of recovery processes stored in the flash memory 84 is three or more.

[0085] If the number of times the recovery process has been performed is less than three (S605: NO), the process proceeds to the first mode process similar to S106 described above (S606).

[0086] If the number of times of recovery processing is three or more (S605: YES), similarly to the above-mentioned S107, the first mode is set to the second mode (S607: "setting processing" of the present invention). After this, the process proceeds to the second mode processing similar to the above-mentioned S108 (S608).

[0087] In S604, if second mode flag information is stored in the flash memory 84 (S604: YES), the control device 80 determines whether the number of consecutive times that the number of abnormal nozzles has been determined to be equal to or greater than the threshold has reached three (the "third predetermined number" of the present invention) (S609), similar to S409 described above.

[0088] If the number of consecutive determinations is less than three (S609: NO), the process proceeds to the second mode process (S608).

[0089] If the number of consecutive determinations reaches three (S609: YES), the second mode is set to the first mode (S610: "setting process" of the present invention) in the same manner as in S110 described above. After this, the process proceeds to the first mode process (S606).

[0090] In this embodiment as well, steps S605, S607, S609, and S610 may be independently processed as needed or periodically in a dedicated flow to perform setting processing for setting either the first or second mode.

[0091] As described above, according to the printer of this embodiment, if the number of abnormal nozzles continues to be equal to or greater than the threshold value while the recovery process is performed three times, the abnormal nozzle is often a nozzle that is difficult to recover. In this case (S605: YES), in S607, the control device 80 sets the mode from the first mode to the second mode. In this embodiment, when the process proceeds to the second mode process through S601 to S603, the recovery process (recovery operation: suction purge) is not performed even if the inspection drive is performed, as in the above-mentioned third embodiment. Therefore, the recovery process for recovering the abnormal nozzles that are difficult to recover is not performed, so the maintenance time can be reduced. In addition, since the recovery process is not performed, the consumption of ink can also be suppressed. Note that the same effects can be obtained in the same configuration as each of the above-mentioned embodiments.

[0092] Next, a printer according to the fifth embodiment will be described below with reference to FIG. 11. The printer in this embodiment is the same as the printer 1 in the first embodiment except for the second mode processing. For this reason, the same parts as those in the first embodiment are indicated by the same reference numerals and the description will be omitted. In this embodiment, the "first condition" of the present invention is satisfied when a recording command signal is received. Also, the "second condition" of the present invention is satisfied when a time signal indicating that a predetermined time has arrived is received. Also, the "second condition" of the present invention is satisfied when the inspection flag information is stored.

[0093] <Second mode processing> In the printer of this embodiment, the control device 80 performs the second mode process according to the flow of Fig. 11. The control device 80 first determines whether the received signal is a recording command signal (S701), similar to S301 described above. If the control device 80 receives a time signal indicating that it is a predetermined time, or if the check flag information is stored in the flash memory 84 (S701: NO), the second mode process ends.

[0094] In S701, if the received signal is a recording command signal (S701: YES), the control device 80 determines whether or not an inspection process has been performed during the day (S702), similar to the above-mentioned S207. In S702, if an inspection process has been performed at least once (S702: YES), the control device 80 determines whether or not recovery flag information is stored in the flash memory 84 (S709), similar to the above-mentioned S213.

[0095] If the inspection process has never been performed (S702: NO), the control device 80 performs an inspection process similar to the above-mentioned S506 (S703). After that, the control device 80 performs S704 and S705 similar to the above-mentioned S507 and S508.

[0096] After S705, and if recovery flag information is stored in the flash memory 84 in S709 (S709: YES), the control device 80 executes S706 which is similar to S214 described above.

[0097] In S704, if the number of abnormal nozzles stored in the flash memory 84 is less than the threshold value (S704: NO), the control device 80 erases the abnormal flag information if abnormal flag information is stored in the flash memory 84 (S707). At this time, the control device 80 resets the variable C, which is the number of recovery processes, to 0, and erases the recovery flag information if recovery flag information is stored in the flash memory 84. Also, at this time, the control device 80 updates the mode flag information stored in the flash memory 84 to first mode flag information (the "setting process" of the present invention).

[0098] After S706 and S707, and if recovery flag information is not stored in the flash memory 84 in S709 (S709: NO), the control device 80 executes a print process similar to S510 described above (S708). In this way, the second mode process ends.

[0099] As described above, according to the printer of this embodiment, as in the first embodiment, if the period during which abnormality flag information was stored in the flash memory 84 (i.e., the period during which the number of abnormal nozzles continues to be equal to or greater than the threshold) has passed three days (first predetermined period), the abnormal nozzle is often a nozzle that is difficult to recover. In this case (S105: YES), in S107, the control device 80 sets the mode from the first mode to the second mode. In this embodiment, when the process proceeds to the second mode process through S101 to S103, when a recording command signal is received (the "first condition" of the present invention), when a time signal indicating that it is a predetermined time is received (the "second condition (a)" of the present invention), and when inspection flag information is stored in the flash memory 84 (the "second condition (b)" of the present invention), the inspection drive is not performed in any of the following cases other than when a recording command signal is received. Therefore, the maintenance time due to the inspection drive can be reduced. In addition, since the inspection drive is not performed, the consumption of ink can also be reduced.

[0100] Furthermore, when the control device 80 receives a recording command signal in the second mode process, the control device 80 performs the inspection process, i.e., the inspection drive, only once per day (the "second mode period" of the present invention). As a result, since the inspection drive is performed only once during the period in which the second mode is set, the maintenance time can be effectively reduced. Also, since the inspection drive is performed only once, the consumption of ink can be reduced.

[0101] In each of the above-described embodiments, the maintenance unit 8 that performs suction purging corresponds to the "recovery means" of the present invention. As a modified example, the inkjet head 4 that performs flushing may also be part of the recovery means. A combination of flushing and suction purging may also be the "recovery operation" of the present invention. Furthermore, only the inkjet head 4 may be the recovery means. In this case, flushing performed as a recovery process corresponds to the "recovery operation" of the present invention. Flushing refers to the control device 80 causing the inkjet head 4 to discharge ink from multiple abnormal nozzles.

[0102] Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible within the scope of the claims. In the above-mentioned embodiments, the trigger for the test drive is the recording command signal, the time signal indicating the predetermined time, and the storage of the test flag information, but the test drive for performing the test process may be executed by other triggers.

[0103] In addition, in each of the above-described embodiments, the test drive is performed on all the nozzles 10 of the inkjet head 4, but this is not limited to the above. For example, the test drive may be performed on only some of the nozzles 10 of the inkjet head 4, such as every other nozzle 10 in each nozzle row 9, and the remaining nozzles 10 may be determined to be abnormal or not based on the determination signal output from the determination circuit 78 during the test drive.

[0104] In addition, in the above-described embodiment, the judgment circuit 78 outputs a signal indicating whether or not the nozzle is abnormal, depending on the potential of the detection electrode 76 when ink is ejected from the nozzle 10 toward the detection electrode 76, but this is not limited to the above.

[0105] For example, a detection electrode extending in the vertical direction may be disposed, and a determination circuit may output a signal indicating whether or not the nozzle is abnormal depending on the potential of the detection electrode when ink is ejected from the nozzle 10 so as to pass through a region facing the detection electrode. Alternatively, an optical sensor (the "signal output unit" of the present invention) may be provided to detect ink ejected from the nozzle 10, and the optical sensor may output a signal indicating whether or not the nozzle is abnormal.

[0106] Alternatively, for example, as described in Patent Gazette No. 4929699, a voltage detection circuit (the "signal output section" of the present invention) that detects the change in voltage when ink is ejected from the nozzles can be connected to a plate on which the nozzles of the inkjet head are formed, and a signal indicating whether or not the nozzle is abnormal can be output from the voltage detection circuit to the control device 80.

[0107] Alternatively, for example, the substrate of the inkjet head may be provided with a temperature detection element (the "signal output unit" of the present invention) as described in Japanese Patent No. 6231759. Then, after applying a first applied voltage to drive the heater for ejecting ink, a second applied voltage is applied to drive the heater so that ink is not ejected, and a signal is output in accordance with whether the nozzle 10 is an abnormal nozzle or not based on the change in temperature detected by the temperature detection element during the period from when the second applied voltage is applied until a predetermined time has elapsed.

[0108] In the above example, the nozzle 10 from which ink is not ejected is determined to be an abnormal nozzle, but this is not limited to the above. For example, a signal output unit may be provided that outputs a signal depending on whether the direction of ink ejection from the nozzle 10 is normal or not, and a nozzle 10 with an abnormality in the ejection direction may be determined to be an abnormal nozzle based on the signal from this signal output unit.

[0109] Also, a signal output unit may be provided that outputs a signal corresponding to the abnormal nozzle state other than the ink not being ejected, and information regarding the abnormal nozzle state may be obtained based on the signal from the signal output unit. The abnormal nozzle state may be, for example, a state in which the ink ejection direction is abnormal, splashes occur, air bubbles are mixed in, or the ink is clogged with paper powder. In this case, the inspection drive may apply pressure to the ink to the extent that the ink is not ejected from the nozzle 10, thereby vibrating the ink in the vicinity of the nozzle 10. Then, a signal corresponding to the vibration state of the ink in the vicinity of the nozzle 10 may be output from the signal output unit to obtain information regarding the abnormal nozzle state.

[0110] In addition, although the suction purge is performed in the recovery process, the present invention is not limited to this. For example, a pressure pump may be provided in the middle of the tube 15 that connects the subtank 3 and the ink cartridge 14. Alternatively, a pressure pump connected to the ink cartridge may be provided in the printer. Then, with the nozzles 10 covered with the caps 71, the pressure pump may be driven to pressurize the ink in the inkjet head 4 and discharge the ink in the inkjet head 4 from the nozzles 10, thereby performing so-called pressure purge.

[0111] Furthermore, in the purging process, both suction by the suction pump 72 and pressurization by the pressure pump may be performed.

[0112] In addition, although the present invention has been described as being applied to a printer equipped with a so-called serial head that ejects ink from multiple nozzles while moving in the scanning direction together with the carriage, the present invention is not limited to this. For example, the present invention can also be applied to a printer equipped with a so-called line head that extends across the entire length of the recording paper P in the scanning direction.

[0113] Also, although an example of application of the present invention to a printer that ejects ink from nozzles to perform recording on recording paper P has been described, the present invention is not limited to this. The present invention can also be applied to printers that record images on recording media other than recording paper, such as T-shirts, sheets for outdoor advertising, cases for mobile terminals such as smartphones, cardboard, and resin members. The present invention can also be applied to liquid ejection devices that eject liquids other than ink, such as liquid resins and metals. [Explanation of symbols]

[0114] 1. Printer (liquid ejection device) 4. Inkjet head (liquid ejection head) 8 Maintenance Unit (Recovery Method) 10 Nozzles 76 Detection electrode (part of the signal output section) 77 High voltage power supply circuit (part of the signal output section) 78 Judgment circuit (part of the signal output section) 79 Resistor (part of signal output section) 80 Control device

Claims

1. a liquid ejection head having a plurality of nozzles for ejecting liquid; a signal output unit that outputs a determination signal indicating whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid; A recovery means for performing a recovery operation to discharge liquid from the nozzle; A control device, The control device includes: a setting process can be executed to selectively set a first mode in which the inspection drive is performed and, after it is determined that the number of the abnormal nozzles is equal to or greater than a threshold value based on the judgment signal transmitted from the signal output unit, the recovery means is caused to perform the recovery operation, and a second mode in which the inspection drive is performed and, even after it is determined that the number of the abnormal nozzles is equal to or greater than a threshold value based on the judgment signal transmitted from the signal output unit, the recovery means is not caused to perform the recovery operation, When the number of abnormal nozzles is equal to or greater than the threshold value during a second predetermined period of time while the first mode is being set in the setting process, the setting process is set to the second mode; A liquid ejection device characterized in that, when the second mode is set in the setting process, if it is determined that the number of abnormal nozzles is less than the threshold value, the setting process is set to the first mode.

2. The control device includes: The liquid ejection device according to claim 1 , wherein the liquid ejection device is configured to switch to the first mode when a third predetermined period has elapsed since the period during which the second mode was set in the setting process.

3. a liquid ejection head having a plurality of nozzles for ejecting liquid; a signal output unit that outputs a determination signal indicating whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid; A recovery means for performing a recovery operation to discharge liquid from the nozzle; A control device, The control device includes: a setting process can be executed to selectively set a first mode in which the inspection drive is performed and, after it is determined that the number of the abnormal nozzles is equal to or greater than a threshold value based on the judgment signal transmitted from the signal output unit, the recovery means is caused to perform the recovery operation, and a second mode in which the inspection drive is performed and, even after it is determined that the number of the abnormal nozzles is equal to or greater than a threshold value based on the judgment signal transmitted from the signal output unit, the recovery means is not caused to perform the recovery operation, When the first mode is set in the setting process, if the number of abnormal nozzles continues to be equal to or greater than the threshold value while the recovery operation is performed a second predetermined number of times, the setting process is set to the second mode, A liquid ejection device characterized in that, when the second mode is set in the setting process, if it is determined that the number of abnormal nozzles is less than the threshold value, the setting process is set to the first mode.

4. The control device includes: A liquid ejection device as described in claim 3, characterized in that when the second mode is set in the setting process, if the number of consecutive times that the number of abnormal nozzles is determined to be equal to or greater than the threshold value reaches a third predetermined number, the setting process sets the liquid ejection device to the first mode.

5. A clock unit that outputs a time signal indicating the time is further provided, 5. The liquid ejection device according to claim 1, wherein the inspection signal is a time signal indicating that it is a predetermined time.

6. 6. The liquid ejection apparatus according to claim 1, wherein the inspection drive is performed by the control device controlling the liquid ejection head to eject liquid from the nozzles.

7. a liquid ejection head having a plurality of nozzles for ejecting liquid; a signal output unit that outputs a determination signal indicating whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid; A control device, The control device includes: a setting process can be executed to selectively set a first mode in which the test drive is performed when at least one of a first condition and a second condition different from the first condition is satisfied, and it is determined whether or not the number of abnormal nozzles is equal to or greater than a threshold value based on the determination signal transmitted from the signal output unit, and a second mode in which the test drive is not performed only when the second condition of the first condition and the second condition is satisfied, When the number of abnormal nozzles is equal to or greater than the threshold value during a first predetermined period of time while the first mode is being set in the setting process, the setting process is set to the second mode; The liquid ejection device, wherein the second mode is characterized in that the test driving when the first condition is satisfied is performed only once during a period of the second mode.

8. 8. The liquid ejection device according to claim 7, wherein the second condition is either (a) a fixed time has arrived, or (b) a predetermined period of time has elapsed since the test drive.

9. A liquid ejection head having a plurality of nozzles for ejecting liquid; a signal output unit that outputs a determination signal indicating whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid; A clock unit that outputs a time signal indicating the time; A control device, The control device includes: A liquid ejection device characterized by being controlled to switch between a first mode in which the inspection drive is performed when a time signal indicating the specified time output from the clock unit is received every day, and a second mode in which the inspection drive is not performed even when a time signal indicating the specified time output from the clock unit is received every day.

10. The inkjet printer further comprises a recovery means for performing a recovery operation to discharge liquid from the nozzle, The control device includes: storing recovery flag information if the number of abnormal nozzles is equal to or greater than a threshold value when the test drive is performed; A liquid ejection device as described in claim 9, characterized in that when a recording command is received, in either the first mode or the second mode, if the recovery flag information is stored, a recovery process is executed to cause the recovery means to perform the recovery operation, and if the recovery flag information is not stored, the recovery process is not executed.

11. The liquid ejection device described in Claim 9, characterized in that when the control device receives a recording command in the first mode, it does not perform the test drive if the test drive has already been performed within a 24-hour period starting from a specified time, and performs the test drive if the test drive has not been performed within the day.

12. The liquid ejection device described in Claim 9, characterized in that when the control device receives a recording command in the second mode, it does not perform the test drive if the test drive has already been performed within a 24-hour period starting from a specified time, and performs the test drive if the test drive has not been performed within the day.

13. The liquid ejection device described in Claim 9, characterized in that the control device transitions to the second mode when, during the first mode, the state in which the number of abnormal nozzles is equal to or greater than a threshold value continues for a predetermined number of days or more.

14. The liquid ejection device of claim 9, characterized in that the control device transitions to the first mode when a period in the second mode has elapsed for a predetermined number of days or more.

15. The liquid ejection device described in Claim 9, characterized in that the control device transitions to the second mode when the number of consecutive times that the number of abnormal nozzles is determined to be equal to or greater than a threshold value during the first mode reaches a predetermined number.

16. The liquid ejection device described in Claim 9, characterized in that the control device continues the first mode when the number of consecutive times that the number of abnormal nozzles is determined to be greater than or equal to a threshold value during the first mode is less than a predetermined number of times.

Images