Liquid droplet ejection device

Abstract

To properly perform maintenance even in a case where the time cannot be grasped in a liquid discharge device.SOLUTION: When the supply of power to a clocking part is stopped and the clocking part loses the time, disappearance flag information is stored. When a printer is turned on after the clocking part loses the time, the clocking part keeps the tentative time with that time as the second time. When the time indicated by the clocking part becomes the first time (S202:YES) in a case where the disappearance flag information is not stored (S201:NO), inspection processing is executed (S205). When the tentative time indicated by the clocking part becomes the second time (S203:YES) in a case where the disappearance flag information is stored (S201:YES), inspection processing is executed (S205).SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a droplet ejection device that ejects droplets 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 nozzles to record on paper. In the printer of Patent Document 1, at a preset time or the like, a pump is driven to apply pressure to perform a maintenance operation that includes purging, which forcibly expels ink from the head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-61673 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, the printer of Patent Document 1 performs a maintenance operation at a preset time. However, in a printer like that of Patent Document 1, when the printer is unplugged, or when the printer is unplugged and the built-in battery runs out, the internal clock is no longer able to keep time. Hereinafter, this state will be referred to as "losing track of time." In this case, even if the printer is subsequently plugged in and power supply to the printer resumes, the printer will not be able to grasp the correct time, and it will not be able to perform a maintenance operation at the appropriate time.

[0005] An object of the present invention is to provide a liquid ejection device that allows appropriate maintenance to be performed even if the clock unit loses track of the time. [Means for solving the problem]

[0006] The liquid ejection apparatus of the present invention includes a liquid ejection head having a nozzle for ejecting liquid, and a test drive for checking whether the nozzle is an abnormal nozzle having an abnormality in ejecting liquid when the liquid ejection head is driven. , indicating whether the nozzle is the abnormal nozzle or not a signal output unit that outputs a judgment signal; a recovery means that performs a recovery operation to discharge liquid from the nozzle; and a clock unit that keeps time; A battery that supplies power to the clock unit; a storage unit; A control device, the control device comprising: When the power supply from the outlet is cut off and the battery runs out, loss flag information indicating that the clock unit has lost track of time is stored in the storage unit, and when the power supply from the outlet is resumed and the loss flag information is not stored in the storage unit, the time indicated by the clock unit is determined to be correct, performing the test drive when the time indicated by the clock unit becomes a first time, and executing a test process for acquiring the determination signal output from the signal output unit; When the power supply from the outlet is resumed, if the disappearance flag information is stored in the storage unit, The power supply to the clock unit is cut off, and the clock unit determines that the clock unit has lost track of time. hand, The inspection process is executed at a predetermined timing after the power is turned on. In addition, the liquid ejection device of the present invention comprises a liquid ejection head having a nozzle that ejects liquid, a signal output unit that outputs a judgment signal indicating whether or not the nozzle is an abnormal nozzle when the liquid ejection head is caused to perform an inspection drive to check whether or not the nozzle is an abnormal nozzle having an abnormality in liquid ejection, a recovery means that performs a recovery operation to discharge liquid from the nozzle, a clock unit that keeps time, and a control device, wherein if the control device determines that the time indicated by the clock unit is correct, it causes the inspection drive to be performed when the time indicated by the clock unit becomes a first time, and executes an inspection process to obtain the judgment signal output from the signal output unit, and if the control device determines that the clock unit has lost track of the time and is measuring the time incorrectly, it executes the inspection process when the time indicated by the clock unit becomes a second time. Effect of the Invention

[0007] If it is determined that the time indicated by the clock unit is correct (if time has not been lost), then by executing the inspection process when the time indicated by the clock unit becomes the first time, it is possible to inspect whether or not the nozzle is abnormal at a desired time, for example, during a time period when the user is not using the liquid ejection device. On the other hand, if it is determined that the clock unit has lost track of the time, then by executing the inspection process at a predetermined timing after the power is turned on, it is possible to inspect whether or not the nozzle is abnormal even if the clock unit has lost track of the time. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a printer according to an 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] 5 is a flowchart showing a flow of processing performed when power is supplied from an outlet or a battery. [Figure 6] 6 is a flowchart showing the flow of processing performed when power is being supplied from an outlet. [Figure 7] 7 is a flowchart corresponding to FIG. 6 of Modification 1. [Figure 8] 10 is a flowchart corresponding to FIG. 6 of Modification 2. [Figure 9] 11 is a flowchart corresponding to FIG. 5 of Modification 3. [Figure 10] 10 is a flowchart corresponding to FIG. 6 of Modification 3. [Figure 11] 13 is a flowchart corresponding to FIG. 6 of Modification 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Preferred embodiments of the present invention will now be described.

[0010] <Overall printer configuration> As shown in FIG. 1, the printer 1 (the "liquid ejection device" of the present invention) according to this 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, an outlet 19, etc.

[0011] 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.

[0012] The subtank 3 is mounted on the carriage 2. Here, the printer 1 is equipped with 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 from the four ink cartridges 14 to the subtank 3.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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 by the cap 71 as described above, a so-called suction purge can be performed in which ink is discharged from within 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.

[0018] 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 either the black ink or the color ink in the inkjet head 4 may be selectively discharged 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.

[0019] 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 a determination drive, which will be described later. 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.

[0020] 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.

[0021] 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 (Vb < Vt < Va) 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.

[0022] 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.

[0023] The outlet 19 can be connected to a commercial power source (not shown). When the outlet 19 is plugged in and connected to the commercial power source, power is supplied to the printer 1 from the outlet 19. When the outlet 19 is unplugged, the supply of power from the outlet 19 is cut off.

[0024] <Printer electrical configuration> Next, the electrical configuration of the printer 1 will be described. As shown in Fig. 4, the printer 1 is equipped with a control device 80. The control device 80 is made up of a CPU (Central Processing Unit) 81, a ROM (Read Only Memory) 82, a RAM (Random Access Memory) 83, a flash memory 84, an ASIC (Application Specific Integrated Circuit) 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, and the like. A determination signal is also input to the control device 80 from a determination circuit 78.

[0025] In addition to the components described above, the printer 1 also includes a display unit 69, an operation unit 70, a clock unit 68, and a battery 67. 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.

[0026] 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, the control device 80 receives a power-on signal (the "predetermined signal" of the present invention) from the operation unit 70 indicating that the printer 1 has been turned on. The clock unit 68 keeps time, and the control device 80 receives a time signal indicating the time from the clock unit 68.

[0027] The battery 67 is connected to at least the control device 80 and the clock unit 68. In the printer 1, the battery 67 is charged when power is being supplied from the outlet 19. In addition, in the printer 1, when the outlet 19 is unplugged and the supply of power from the outlet 19 is cut off, power is supplied from the battery 67 to at least the control device 80 and the clock unit 68, provided that the battery 67 is not dead.

[0028] 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.

[0029] <Processing when power is supplied from an outlet or battery> Next, a process performed when power is being supplied from the outlet 19 or the battery 67 to the control device 80 and the clock unit 68 in the printer 1 will be described.

[0030] At this time, the control device 80 executes processing according to the flow of Fig. 5. The flow of Fig. 5 starts, for example, when the battery 67 is out of battery and the outlet 19 is plugged into a commercial power source to start supplying power to the printer 1.

[0031] 5 in more detail, the control device 80 judges whether or not loss flag information is stored in the flash memory 84 (the "storage unit" of the present invention) (S101). The loss flag information is information indicating that the power supply to the clock unit 68 has been cut off because the power outlet 19 has been unplugged and the battery 67 has run out, causing the clock unit 68 to lose track of time.

[0032] If no loss flag information is stored in the flash memory 84 (S101: NO), the control device 80 then judges whether the battery 67 will run out of battery (S102). In S102, for example, when the outlet 19 is unplugged and the charging rate of the battery 67 is less than a predetermined threshold, it is judged that the battery 67 will run out of battery. Also, in S102, for example, when the outlet 19 is plugged in and the charging rate of the battery 67 is equal to or greater than a predetermined threshold, it is judged that the battery 67 will not run out of battery.

[0033] If the battery 67 does not run out (S102: NO), the process returns to S101. If the battery 67 runs out (S102: YES), the control device 80 stores the loss flag information in the flash memory 84 (S103), and the process returns to S101.

[0034] If a loss flag is stored in the flash memory 84 (S101: YES), the control device 80 returns to S101 if it has not received any of a power-on signal, a time setting signal, or a recording command including time information (S104: NO, S105: NO, S106: NO).

[0035] The power-on signal is a signal that instructs turning on the power of the printer 1, and is input by the user operating the operation unit 70. The time setting signal is a signal for setting the time that is input by the user operating the operation unit 70. The recording command including time information is a recording command including information on the transmission time that is input to the printer 1 from, for example, a PC (not shown) connected to the printer 1.

[0036] Furthermore, when the control device 80 receives a power-on signal (S104: YES), it determines whether or not the clock unit 68 is timing a provisional time (S107). The provisional time is the time at which timing starts in S108, which will be described next, after the clock unit 68 loses track of the time as described above.

[0037] If the clock unit 68 is timing the provisional time (S107: YES), the process returns to S101. If the clock unit 68 is not timing the provisional time (S107: NO), the control device 80 causes the clock unit 68 to set the current time as the second time (e.g., 0:00), start timing the provisional time (S108), and returns to S101.

[0038] Furthermore, when the control device 80 receives a time setting signal (S105: YES) and a recording command including time information (S106: YES), it sets the time of the clock unit 68 and causes the clock unit 68 to start timing (S109). At this time, the control device 80 sets the time of the clock unit 68 to the time indicated by the time setting signal or the time indicated by the time information included in the recording command. Thereafter, the control device 80 erases the disappearance flag information stored in the flash memory 84 (S110) and returns to S101.

[0039] <Processing when power is supplied from the outlet> Next, the process when power is being supplied from the outlet 19 will be described. At this time, the control device 80 performs the process according to the flow of Fig. 6. The flow of Fig. 6 starts when the outlet 19 is inserted and connected to a commercial power source. Note that, when power is being supplied from the outlet 19, the control device 80 performs the process shown in the flow of Fig. 5 and the process shown in the flow of Fig. 6 in parallel.

[0040] 6 in more detail, the control device 80 determines whether or not loss flag information is stored in the flash memory 84 (S201). If loss flag information is not stored in the flash memory 84 (S201: NO), the control device 80 determines whether or not the time indicated by the clock unit 68 is the first time (S202).

[0041] Furthermore, if the disappearance flag information is stored in the flash memory 84 (S201: YES), the control device 80 judges whether or not the provisional time indicated by the clock unit 68 is the second time (S203). Furthermore, if the control device 80 judges in S202 that the time indicated by the clock unit 68 is not the first time (S202: NO) and if the control device 80 judges in S203 that the provisional time indicated by the clock unit 68 is not the second time (S203: NO), the control device 80 judges whether or not a recording command has been received (S204). If a recording command has not been received (S204: NO), the control device 80 returns to S201.

[0042] If no disappearance flag information is stored in the flash memory 84 (S201: NO) and the time indicated by the clock unit 68 is the first time (S202: YES), the control device 80 then executes an inspection process (S205). In the inspection process, the control device 80 causes the inkjet head 4 to perform an inspection drive that drives the inkjet head 4 to eject ink from each of the multiple nozzles 10 in turn. At this time, the control device 80 also receives a determination signal output from the determination circuit 78 during the inspection drive.

[0043] Next, the control device 80 determines whether or not there is an abnormal nozzle among the multiple nozzles 10 of the inkjet head 4 based on the determination signal received during the inspection process (S206). If there is no abnormal nozzle (S206: NO), the process returns to S201.

[0044] If an abnormal nozzle is present (S206: YES), the control device 80 stores recovery flag information indicating that a recovery operation is required in the flash memory 84 (S207). Next, the control device 80 executes a flushing process (S208) and returns to S201. In the flushing process of S208, the control device 80 causes the inkjet head 4 to perform flushing to eject ink from a plurality of abnormal nozzles. In this flushing, ink may be ejected only from the abnormal nozzles, or ink may be ejected from at least some of the nozzles 10 that are not abnormal, in addition to the abnormal nozzles.

[0045] Also, if loss flag information is stored in the flash memory 84 (S201: YES) and the provisional time indicated by the clock unit 68 is the second time (S203: YES), the control device 80 also executes the processes of S205 to S208.

[0046] On the other hand, when a recording command is received (S204: YES), if the received recording command is not the first recording command after the inspection process is executed (the "predetermined signal" of the present invention) (S209: NO), the control device 80 proceeds to S213. Also, if the received recording command is the first recording command after the inspection process is executed (S209: YES) and recovery flag information is not stored in the flash memory 84 (S210: NO), the control device 80 proceeds to S213.

[0047] If the received recording command is the first recording command since the last inspection process was executed (S209: YES) and recovery flag information is stored in the flash memory 84 (S210: YES), the control device 80 then executes a purge process (S211) and erases the recovery flag information stored in the flash memory 84 (S212), before proceeding to S213.

[0048] In S213, the control device 80 executes a recording process. In the recording process, the control device 80 controls the carriage motor 86 to move the carriage 2 in the scanning direction while repeating a recording pass in which the inkjet head 4 ejects ink from the multiple nozzles 10 toward the recording paper P, and a conveying operation in which the conveying rollers 6, 7 convey the recording paper P a predetermined distance, thereby recording an image on the recording paper P. Then, after the recording process, the process returns to S201.

[0049] In this embodiment, the inkjet head 4 that performs flushing and the maintenance unit 8 that performs suction purging correspond to the "recovery means" of the present invention. In this embodiment, the combination of flushing and suction purging corresponds to the "recovery operation" of the present invention, of which flushing corresponds to "a part of the recovery operation" of the present invention, and suction purging corresponds to "the remaining part of the recovery operation excluding a part" of the present invention.

[0050] <Effects> In this embodiment, if it is determined that the time indicated by the clock unit 68 is correct (if the time has not been lost), the inspection process is executed when the time indicated by the clock unit 68 becomes the first time. As a result, if the first time is set to a desired time, such as a time period when the user is not using the printer 1, it is possible to inspect whether or not there is an abnormal nozzle at the time desired by the user. On the other hand, if it is determined that the clock unit 68 has lost track of the time, the time when the power was turned on is set as the second time, and the clock unit 68 is made to keep a provisional time. Then, from this point on, the inspection process is executed when the provisional time indicated by the clock unit 68 becomes the second time. As a result, the inspection process can be executed periodically even if the clock unit 68 has lost track of the time.

[0051] Furthermore, in this embodiment, when the clock unit 68 returns from a state in which it has lost track of the time to a state in which it has not lost track of the time (a state in which the time indicated by the clock unit 68 is determined to be correct), the timing for executing the check process is returned so that the check process is executed when the time indicated by the clock unit 68 becomes the first time. This allows the check process to be executed at an appropriate timing desired by the user after the clock unit 68 has returned to a state in which it has not lost track of the time.

[0052] Furthermore, in this embodiment, when the battery runs out, loss flag information is stored in the flash memory 84. In this way, depending on whether loss flag information is stored in the flash memory 84, it is possible to determine whether the clock unit has lost track of time.

[0053] Furthermore, if the test drive is performed and the judgment signal indicates that there is an abnormal nozzle, and a recovery operation is immediately performed, as opposed to the present embodiment, there is a risk that the liquid in the inkjet head 4 will thicken during the long period between the test drive and receiving a recording command. In this case, it will be necessary to perform a recovery operation again when a recording command is received, and as a result, the discharge of ink by the recovery operation performed immediately after the test drive will be wasted.

[0054] In contrast, in this embodiment, a test drive is performed, and if the judgment signal indicates that an abnormal nozzle exists, recovery flag information is stored in the flash memory 84. Then, when the first recording command is received after the test drive, if the recovery flag information is stored in the flash memory 84, a recovery operation is performed. As a result, even if there is a long period of time between the test drive and receiving the first recording command after the test drive, the ink is not wasted as described above.

[0055] In this embodiment, a test drive is performed, and if the judgment signal indicates that an abnormal nozzle exists, flushing, which is part of the recovery operation, is performed immediately after the test drive. Then, when the first recording command is received after the test drive, suction purging, which is the remainder of the recovery operation excluding the above part, is performed before the recording process. This makes it possible to shorten the time required for the recovery operation to be performed before the recording process when the recording command is received.

[0056] <Modification> Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and various modifications are possible within the scope of the claims.

[0057] In the above-described embodiment, the loss flag information is stored in the flash memory 84 (S201: YES), and when the provisional time indicated by the clock unit 68 becomes the second time (S203: YES), the processes of S205 to S208 are executed, but this is not limited to this.

[0058] In the first modification, the control device 80 performs processing according to the flow of Fig. 7, instead of processing according to the flow of Fig. 6 in the above embodiment. The flow of Fig. 7 is obtained by replacing S203 in the flow of Fig. 6 with S301.

[0059] In S301, the control device 80 determines whether the tentative time indicated by the clock unit 68 is a third time, which is earlier than the second time. If the tentative time indicated by the clock unit 68 is not the third time (S301: NO), the control device 80 proceeds to S204. If the tentative time indicated by the clock unit 68 is the third time (S301: YES), the control device 80 executes the processes of S205 to S208.

[0060] In the first modification, if the clock unit 68 loses track of time when the power is turned on, the time when the power is turned on is set as the second time, and the clock unit 68 is made to keep a provisional time. Then, from this point on, the inspection process is executed when the provisional time indicated by the clock unit 68 becomes the third time before the second time. This allows the inspection process to be executed periodically even when the clock unit 68 loses track of time. Furthermore, since a user normally turns on the power when using the printer, if the inspection process is executed when the provisional time indicated by the clock unit 68 becomes the third time before the second time, the inspection process can be executed at a timing when it is highly likely that the user is not using the printer.

[0061] Furthermore, in the above-described embodiment and modified example 1, when the clock unit 68 returns from a state in which it has lost track of the time to a state in which it has not lost track of the time (a state in which the time indicated by the clock unit 68 is determined to be correct), the timing for executing the check process is returned so that the check process is executed when the time indicated by the clock unit 68 becomes the first time. However, this is not limited to this. For example, even after the clock unit 68 returns from a state in which it has lost track of the time to a state in which it has not lost track of the time, the check process may be executed at a time other than the first time, such as a second time or a third time.

[0062] Furthermore, when the clock unit 68 loses track of the time, the clock unit 68 may be caused to measure a provisional time and perform an inspection process or the like based on the provisional time.

[0063] In the second modification, the control device 80 performs processing according to the flow of Fig. 8, instead of processing according to the flow of Fig. 6 in the above embodiment. In the flow of Fig. 8, when no loss flag information is stored in the flash memory 8 (S201: NO) and the time indicated by the clock unit 68 is not the first time (S202: NO), it is determined whether or not a power-on signal has been received (S401). When a power-on signal has not been received (S401), the process proceeds to S204.

[0064] When a power-on signal is received (S401: YES), the control device 80 executes a recovery process (S402). In the recovery process, the control device 80 controls at least some of the components of the printer 1 to perform a recovery operation for returning the printer 1 to a state in which it is possible to record on the recording paper P. The recovery operation is, for example, an operation for adjusting the origin positions of the carriage 2 and the cap 71.

[0065] Next, the control device 80 judges whether the elapsed time T from when the printer 1 was last turned off until it was turned on is longer than a predetermined time Th based on the time signal received from the clock unit 68 (S403). If the elapsed time T is equal to or less than the predetermined time Th (S403: NO), the process proceeds to S204. If the elapsed time T is longer than the predetermined time Th (S403: YES), the process proceeds to S205.

[0066] On the other hand, when it is determined in S201 that the loss flag information is stored in the flash memory 84 (S201: YES), the control device 80 also determines whether or not a power-on signal has been received (S404).

[0067] When the power-on signal has not been received (S404: NO), the process proceeds to S204. When the power signal has been received (S404: YES), the control device 80 executes a recovery process similar to that of S402 (S405), and then proceeds to S205.

[0068] In Modification 2, if the clock unit 68 loses track of time, the inspection process is executed after the recovery operation when the power is turned on. If the battery runs out, the printer 1 cannot know how much time has passed since the power was last turned off. However, in Modification 2, because the inspection process is executed after the recovery operation, it is possible to know whether the nozzle 10 is an abnormal nozzle or not, and it is possible to carry out a recovery operation thereafter only if necessary. This makes it possible to reduce unnecessary consumption of ink.

[0069] In addition, in the second modification, the inspection process is executed after the recovery operation, but the timing is not limited to this. In the second modification, the inspection process may be executed within the period from when the power is turned on to when the recovery operation is started, such as immediately before the processes of S402 and S405.

[0070] In the third modification, the control device 80 performs processing along the flows in FIGS. 9 and 10, instead of the processing along the flows in FIGS. 5 and 6 of the above-described embodiment.

[0071] In the flow of FIG. 9, the processes of S104, S107, and S108 in the flow of FIG. 5 are not performed, and when it is determined in S101 that the loss flag information is stored in the flash memory 84 (S101: YES), the flow proceeds to S105.

[0072] Also, in the flow of FIG. 10, when it is determined in S201 that the loss flag information is stored in the flash memory 84 (S201: YES), the control device 80 determines whether or not a power-on signal has been received (S501).

[0073] When the power-on signal has not been received (S501: NO), the process proceeds to S204. When the power signal has been received (S501: YES), the control device 80 waits until a predetermined time has elapsed (S502: NO), and when the predetermined time has elapsed (S502: YES), the process proceeds to S205.

[0074] In the third modification, even if the clock unit 68 loses track of time, the inspection process can be executed when a predetermined time has elapsed since the power was turned on. Also, while there is a high possibility that the user will use the printer immediately after the power is turned on, by executing the inspection process when a predetermined time has elapsed since the power was turned on as in the third modification, the inspection process can be executed when there is a high possibility that the user will not be using the printer.

[0075] In the fourth modification, the control device 80 performs processing along the flow shown in FIG. 11, instead of the processing along the flow shown in FIG. 6 in the above embodiment.

[0076] In the flow of FIG. 11, when it is determined in S201 that loss flag information is stored in the flash memory 84 (S201: YES), and when the time indicated by the clock unit 68 in S202 is not the first time (S202: NO), the flow proceeds to S204.

[0077] If it is determined in S204 that a recording command has not been received (S204: NO), the process returns to S201. If it is determined in S204 that a recording command has been received (S204: YES), the control device 80 determines whether the received recording command is the first recording command received after receiving an ON signal. Here, the "first recording command received after receiving an ON signal" refers to the first recording command received after the power of the printer 1 is turned on after the clock unit 68 loses track of time.

[0078] If the received recording command is not the first recording command received after receiving the ON signal (S601: NO), proceed to S213. If the received recording command is the first recording command received after receiving the ON signal (S601: YES), the control device 80 stores recording flag information indicating that recording will be performed in the flash memory 84 (S602) and proceeds to S205.

[0079] In addition, in the fourth modification, if it is determined in S206 that there is no abnormal nozzle (S206: NO) and after executing the flushing process of S208, the control device 80 determines whether or not recording flag information is stored in the flash memory 84 (S603). If recording flag information is not stored in the flash memory 84 (S603: NO), the process returns to S201. If recording flag information is stored in the flash memory 84 (S603: YES), the recording flag information stored in the flash memory 84 is erased (S604) and the process proceeds to S210.

[0080] In the fourth modification, even if the clock unit 68 loses track of time, the inspection process can be executed before the first recording on the recording paper P is performed after the printer is turned on.

[0081] In the above embodiment, when the determination signal output from the determination circuit 78 during the test drive indicates that an abnormal nozzle exists, flushing is performed as part of the recovery operation. Then, when the first recording command is received after the test drive, suction purging is performed as the remainder of the recovery operation excluding the above-mentioned part. However, this is not limited to the above.

[0082] For example, the printer 1 may be configured to selectively record in either low image quality or high image quality, and the processes of S210 to S213 may be executed when a recording command for recording in high image quality is received for the first time after the test drive.

[0083] Furthermore, the suction purge as the remainder of the recovery operation excluding the above-mentioned part is not necessarily performed when a recording command is received. For example, the suction purge as the remainder of the recovery operation excluding the above-mentioned part may be performed when a predetermined signal other than a recording command is received.

[0084] Further, the present invention is not limited to the case where part of the recovery operation is flushing and the rest of the recovery operation excluding the part is suction purging.

[0085] For example, the recovery operation may be suction purging, and when a judgment signal output from the judgment circuit 78 during the inspection drive indicates that an abnormal nozzle exists, a part of the suction purging may be performed as part of the recovery operation. Furthermore, when a specified signal is subsequently received, the remaining part of the suction purging may be performed as the remainder of the recovery operation excluding the part mentioned above.

[0086] Alternatively, for example, the recovery operation may be flushing, and when the determination signal output from the determination circuit 78 during the test drive indicates that an abnormal nozzle exists, part of the flushing may be performed as part of the recovery operation. Furthermore, when a prescribed signal is subsequently received, the remaining part of the flushing may be performed as the remainder of the recovery operation excluding the part described above.

[0087] In addition, when the judgment signal output from the judgment circuit 78 during the inspection drive indicates that an abnormal nozzle exists, a part of the recovery operation may be performed, and then, when a specified signal is received, the remainder of the recovery operation excluding the part mentioned above may be performed.

[0088] For example, when the judgment signal output from the judgment circuit 78 during inspection drive indicates that an abnormal nozzle exists, some of the recovery operations may not be performed, and then, when a specified signal is received, all of the recovery operations may be performed.

[0089] Alternatively, for example, when the judgment signal output from the judgment circuit 78 during inspection driving indicates that an abnormal nozzle is present, all recovery operations may be performed immediately, and then, when a specified signal is received, no recovery operations may be performed.

[0090] In the above embodiment, the inspection drive is performed for all the nozzles 10 of the inkjet head 4, but this is not limited to the above. For example, the inspection drive may be performed for 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 inspection drive.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] In the above embodiment, a uniform suction purge is performed in the purge process, but this is not limited to the above. For example, the maintenance unit 8 may be configured to selectively perform one of a plurality of types of suction purge with different ink discharge amounts. The ink discharge amount may differ between the plurality of types of suction purge, for example, by varying at least one of the driving time of the suction pump 72 and the rotation speed of the suction pump 72. In the purge process, for example, the greater the number of abnormal nozzles, the greater the suction purge that is performed.

[0097] In the above example, the purging process is performed by suction purging, but 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, the printer may be provided with a pressure pump connected to the ink cartridge. 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 from the inkjet head 4 through the nozzles 10, thereby performing a so-called pressure purging.

[0098] Furthermore, in the purging process, both suction by the suction pump 72 and pressurization by the pressure pump may be performed.

[0099] In the above example, the printer is equipped with a battery that supplies power to the clock unit, and the clock unit loses track of time when the power supply from the outlet is cut off and the battery runs out, but this is not limited to the above. For example, the printer may not be equipped with a battery that supplies power to the clock unit, and the clock unit may lose track of time when the power supply from the outlet is cut off.

[0100] In the above, an example has been described in which the present invention is 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, but 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.

[0101] In the above, an example of applying the present invention to a printer that ejects ink from nozzles to perform recording on recording paper P has been described, but 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]

[0102] 1. Printer 4 Inkjet head 8 Maintenance Unit 10 Nozzles 67 Battery 68 Clock section 72 Suction Pump 76 Detection electrode 77 High Voltage Power Supply Circuit 78 Judgment circuit 79 Resistance 80 Control device 84 Flash Memory

Claims

1. a liquid ejection head having a nozzle 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 clock unit that measures time; A battery that supplies power to the clock unit; A storage unit; A control device, The control device includes: when the power supply from the outlet is cut off and the battery runs out of power, loss flag information indicating that the clock unit has lost track of time is stored in the storage unit; when the power supply from the outlet is resumed, if the disappearance flag information is not stored in the storage unit, it is determined that the time indicated by the clock unit is correct, and when the time indicated by the clock unit becomes a first time, the test drive is performed, and a test process is executed to obtain the determination signal output from the signal output unit; A liquid ejection device characterized in that, if the loss flag information is stored in the memory unit when power supply from the outlet is resumed, the device determines that the clock unit has lost track of time due to the loss of power supply to the clock unit, and executes the inspection process at a predetermined time after the power is turned on.

2. The control device includes: When the power is turned on, if the clock unit loses track of time, causing the clock unit to measure a provisional time by setting the time when the power is turned on as a second time; The liquid ejection device according to claim 1 , wherein the inspection process is executed at the predetermined timing, which is a timing when the tentative time indicated by the clock unit becomes the second time.

3. The control device includes: When the power is turned on, if it is determined that the clock unit has lost track of time, causing the clock unit to measure a provisional time by setting the time when the power is turned on as a second time; The liquid ejection device according to claim 1 , wherein the inspection process is executed at the predetermined timing, which is a timing when the tentative time indicated by the clock unit becomes a third time that is earlier than the second time.

4. The control device includes: A liquid ejection device as described in claim 2 or 3, characterized in that when the clock unit returns from a state of timing the provisional time to a state of timing a time determined to be correct, and thereafter the time indicated by the clock unit becomes the first time, the inspection process is executed.

5. The control device includes: When the power supply is turned on, the liquid ejection head is caused to perform a predetermined return operation; 2. The liquid ejection device according to claim 1, wherein the predetermined timing is a timing within a period from when the power source is turned on until the return operation starts, or a timing after the return operation.

6. 2. The liquid ejection device according to claim 1, wherein the predetermined timing is a timing when a predetermined time has elapsed since the power supply was turned on.

7. The control device includes: When receiving an ejection instruction signal instructing to eject liquid onto the ejection receiving medium, the liquid ejection head is caused to eject liquid from the nozzle onto the ejection receiving medium; The liquid ejection device according to claim 1, characterized in that the specified timing is a timing immediately before the liquid ejection head ejects liquid from the nozzle onto the ejection medium based on the ejection instruction signal first received after the power is turned on.

8. A storage unit, The control device includes: When the determination signal transmitted from the determination signal output unit indicates that an abnormal nozzle is present in the inspection process, recovery flag information indicating that the recovery operation is necessary is stored in the storage unit; A liquid ejection device as described in any one of claims 1 to 7, characterized in that when a specified signal is subsequently received, if the recovery flag information is stored in the memory unit, the recovery means is caused to perform the recovery operation.

9. the predetermined signal is an ejection instruction signal that instructs the ejection of liquid onto an ejection receiving medium, The control device includes: A liquid ejection device as described in claim 8, characterized in that if the recovery flag information is stored in the memory unit when the ejection instruction signal is received, the recovery means is caused to perform the recovery operation, and then the liquid ejection head is caused to eject liquid from the nozzle onto the ejection medium.

10. 10. The liquid ejection device according to claim 9, wherein the predetermined signal is the ejection instruction signal that is received first after the inspection process is executed.

11. The control device includes: in the inspection process, when the signal transmitted from the judgment signal output unit during the inspection drive indicates that an abnormal nozzle is present, recovery flag information indicating that the recovery operation is necessary is stored in the storage unit, and the recovery means is caused to perform a part of the recovery operation; A liquid ejection device as described in any one of claims 8 to 10, characterized in that when the specified signal is received, if the recovery flag information is stored in the memory unit, the recovery means is caused to perform the remainder of the recovery operation except for the part of it.

12. The recovery means includes: a pump connectable to the liquid ejection head; 12. The liquid ejection apparatus according to claim 1, wherein the recovery operation includes a purge that drives the pump to discharge the liquid in the liquid ejection head from the nozzles.

13. The recovery means includes: The liquid ejection head includes:

13. The liquid ejection apparatus according to claim 1, wherein the recovery operation includes flushing, which drives the liquid ejection head to eject liquid from the nozzles.

14. The recovery means includes: The liquid ejection head; a pump connectable to the liquid ejection head; the part of the recovery operation is flushing that drives the liquid ejection head to discharge liquid from the nozzles, 12. The liquid ejection apparatus according to claim 11, wherein the remaining part of the recovery operation is a purge that drives the pump to discharge the liquid in the liquid ejection head from the nozzle.

15. a liquid ejection head having a nozzle 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 clock unit that measures time; A control device, The control device includes: when it is determined that the time indicated by the clock unit is correct, performing the test drive when the time indicated by the clock unit becomes a first time, and executing a test process to obtain the determination signal output from the signal output unit; A liquid ejection device characterized in that, when the clock unit loses track of the time and determines that the time being measured is incorrect, the inspection process is executed when the time indicated by the clock unit reaches a second time.

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