Liquid dispensing device

Abstract

To shorten time until discharge of liquid to a discharged medium is completed after the discharge of the liquid to the discharged medium has been instructed as much as possible.SOLUTION: A liquid discharge device starts an inspection operation for inspecting whether a nozzle is an abnormal nozzle (S103), when receiving a time signal indicating that time becomes predetermined time (S101: YES). The liquid discharge device interrupts the inspection operation (S106), and performs a recording operation (S107), when receiving a recording command during the inspection operation (S105: YES). The liquid discharge device starts the recording operation (S114), when receiving a recording command (S102: YES). The liquid discharge device performs the inspection operation (S103) after completion of the recording operation (S117: YES), when receiving a time signal indicating that the time becomes predetermined time during the recording operation (S116: YES).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 performs recording by ejecting ink from nozzles. In the printer of Patent Document 1, when the printer is in a regular cleaning mode in which cleaning is performed periodically at predetermined intervals, the ejection state of each nozzle is inspected at predetermined intervals, and a cleaning process is performed based on the inspection results. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-157483 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, in the periodic cleaning mode, a signal instructing to start recording may be received while the ejection state of each nozzle is being inspected. In this case, if recording is started after the ejection state inspection and the cleaning process based on the inspection result are completed, it will take a long time from when the signal instructing to start recording is received until recording is completed.

[0005] An object of the present invention is to provide a liquid ejection device that can shorten as much as possible the time from when an instruction to eject liquid onto an ejection receiving medium is given until the ejection of liquid onto the ejection receiving medium is completed. [Means for solving the problem]

[0006] A liquid ejection device of the present invention comprises a liquid ejection head having a plurality of nozzles that eject liquid onto an ejection receiving medium; a signal output unit that outputs a determination signal according to 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 that is abnormal in the ejection of liquid; and a control device, wherein the control device is capable of receiving an ejection instruction signal that instructs the liquid ejection head to perform an ejection operation that causes the liquid ejection head to eject liquid from the plurality of nozzles, and an inspection instruction signal that is received regardless of the timing of the ejection operation and instructs the liquid ejection head to inspect whether or not the nozzle is the abnormal nozzle; when the control device receives the ejection instruction signal, it causes the liquid ejection head to perform the ejection operation; when the control device receives the inspection instruction signal, it causes the liquid ejection head to perform an inspection operation that sequentially performs the inspection drive for at least two nozzles out of the plurality of nozzles; and when the control device receives the ejection instruction signal in the middle of the inspection operation, it causes the liquid ejection head to interrupt the inspection operation and perform the ejection operation. If a waiting period exists during the ejection operation that is performed by the liquid ejection head after the inspection operation has been interrupted, the liquid ejection head is caused to resume the inspection operation during the waiting period, and is caused to perform the inspection drive for at least the nozzles for which the inspection drive has not been completed before the interruption of the ejection operation. .

[0008] Furthermore, the liquid ejection device of the present invention comprises a liquid ejection head having a plurality of nozzles that eject liquid onto an ejection receiving medium, a signal output unit that outputs a determination signal according to 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 that is abnormal in the ejection of liquid, and a control device, wherein the control device is capable of receiving an ejection instruction signal that instructs the liquid ejection head to perform an ejection operation to eject liquid from the plurality of nozzles, and an inspection instruction signal that is received regardless of the timing of the ejection operation and instructs the liquid ejection head to inspect whether or not the nozzle is an abnormal nozzle, and when the control device receives the ejection instruction signal, causes the liquid ejection head to perform the ejection operation, and when the control device receives the inspection instruction signal, causes the liquid ejection head to perform an inspection operation that sequentially performs the inspection drive for at least two nozzles out of the plurality of nozzles, and when the control device receives the inspection instruction signal during the ejection operation and there is a standby period during the ejection operation, continues the ejection operation and causes the liquid ejection head to perform the inspection operation during the standby period. [Effects of the Invention]

[0010] In the present invention, the time from when the ejection instruction signal is received until the ejection operation is completed can be shortened as much as possible. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic configuration diagram of a printer according to an embodiment of the present invention. [Figure 2] 10A and 10B are diagrams for explaining detection electrodes arranged in a cap, and the connection relationship between the detection electrodes and a high-voltage power supply circuit and a determination circuit. [Figure 3] FIG. 10A is a diagram showing the change in potential of the detection electrode when ink is ejected from the nozzle, and FIG. 10B is a diagram showing the change in potential 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. [Figure 5]10 is a flowchart showing a flow of processing by the control device. [Figure 6] FIG. 10 is a diagram for explaining the association between the number of abnormal nozzles and the recovery operation. [Figure 7] 10 is a flowchart showing a flow of processing by a control device in Modification 1. [Figure 8] 10 is a flowchart showing a flow of processing by a control device in Modification 2. [Figure 9] 9 is a flowchart showing the flow of processing from A onward shown in FIG. 8. [Figure 10] FIG. 11 is a block diagram showing the electrical configuration of a printer according to a third modification. [Figure 11] 10 is a flowchart showing the flow of processing by the control device in Modification 3. [Figure 12] 10 is a flowchart showing the flow of processing by the control device in Modification 4. DETAILED DESCRIPTION OF THE INVENTION

[0012] Preferred embodiments of the present invention will now be described.

[0013] <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, conveying rollers 6 and 7, and a maintenance unit 8 (the "recovery means" of the present invention).

[0014] The carriage 2 is supported by two guide rails 11 and 12 extending in the scanning direction. The carriage 2 is connected to a carriage motor 86 (see FIG. 4) via a belt or the like (not shown), and when the carriage motor 86 is driven, the carriage 2 moves in the scanning direction along the guide rails 11 and 12. In the following description, the right and left sides of the scanning direction are defined as shown in FIG.

[0015] The subtank 3 is mounted on the carriage 2. 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 right side in the scanning direction, they store black, yellow, cyan, and magenta inks ("liquids" according to the present invention). The subtank 3 is connected to the four ink cartridges 14 attached to the cartridge holder 13 via four tubes 15. This allows the four colors of ink to be supplied from the four ink cartridges 14 to the subtank 3.

[0016] 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, the nozzle face 4a. More specifically, the plurality of nozzles 10 are arranged in a transport direction perpendicular to the scanning direction to form nozzle rows 9, and on the nozzle face 4a, four nozzle rows 9 are aligned in the scanning direction. From the plurality of nozzles 10, black, yellow, cyan, and magenta inks are ejected, starting with the nozzles constituting the nozzle row 9 on the right side in the scanning direction.

[0017] 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.

[0018] 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.

[0019] 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, and the cap 71 is raised by the cap lifting mechanism 88, 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, for example, cover the plurality of nozzles 10 by coming into close contact with a frame or the like (not shown) that is arranged around the nozzle surface 4a of the inkjet head 4.

[0020] 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, it is possible to perform a so-called suction purge, 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.

[0021] In this embodiment, one of three types of suction purge can be selectively performed: weak purge, medium purge, and strong purge. The medium purge discharges more ink than the weak purge, and the strong purge discharges more ink than the medium purge. The weak, medium, and strong purges differ in the amount of ink discharged, for example, because at least one of the driving time of the suction pump 72 and the rotation speed of the suction pump 72 differs.

[0022] For convenience, the cap 71 has been described as covering all of the nozzles 10 together, and ink in the inkjet head 4 is discharged from all of the nozzles 10 during suction purging. However, this is not limiting. For example, the cap 71 may have separate portions covering the nozzles 10 constituting the rightmost nozzle row 9 that ejects black ink and the nozzles 10 constituting the three leftmost nozzle rows 9 that eject color inks (yellow, cyan, and magenta ink), so that either the black ink or the color ink in the inkjet head 4 can be selectively discharged during suction purging. Alternatively, for example, a separate cap 71 may be provided for each nozzle row 9, so that ink can be discharged from the nozzles 10 for each nozzle row 9 individually during suction purging.

[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 (e.g., approximately 600 V) is applied to the detection electrode 76 by the high-voltage power supply circuit 77 during determination driving, which will be described later. Meanwhile, the inkjet head 4 is held at 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. 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 (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.

[0026] Furthermore, although a positive potential is applied to the detection electrode 76 by the high-voltage power supply circuit 77 here, a negative potential (for example, about −600 V) may also be applied to the detection electrode 76 by the high-voltage power supply circuit 77. In this case, conversely to the above, when ink is ejected from the nozzles 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 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 drops and returns to potential Va.

[0027] <Printer electrical configuration> Next, we will explain the electrical configuration of the printer 1. As shown in Figure 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, etc. The control device 80 controls the operations of a carriage motor 86, an inkjet head 4, a transport motor 87, a cap lifting mechanism 88, a suction pump 72, a high-voltage power supply circuit 77, etc.

[0028] In addition to the components described above, the printer 1 also includes a clock unit 70. The clock unit 70 keeps track of time and outputs a time signal indicating the current time. The control device 80 receives the time signal from the clock unit 70.

[0029] 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.

[0030] <Printer control by a control device> Next, a description will be given of the control of the printer 1 by the control device 80. The control device 80 controls the operation of the printer 1 by performing processing in accordance with the flow of FIG.

[0031] To explain in more detail, the control device 80 waits while it has not received a time signal (the "inspection instruction signal" of the present invention) from the clock unit 70 indicating that a predetermined time has arrived (S101: NO) and while it has not received a recording command (the "ejection instruction signal" of the present invention) instructing recording on the recording paper P (S102: NO).

[0032] When a time signal indicating that a predetermined time has arrived is received (S101: YES), the control device 80 causes the inkjet head 4 to start an inspection operation (S103). The inspection operation is an operation in which, with the carriage 2 positioned at the maintenance position, the inkjet head 4 sequentially performs inspection driving for each of the multiple nozzles 10. The inspection driving is the driving of the inkjet head 4 to eject ink from the nozzles 10. In other words, the inspection driving is the driving of the inkjet head 4 to check whether the nozzle 10 is an abnormal nozzle that is abnormal in ejecting ink.

[0033] Then, as long as the inspection operation is not completed (S104: NO) and no recording command is received during the inspection operation (S105: NO), the inspection operation is continued. When the inspection operation is completed (S104: YES), the process proceeds to S108. When a recording command is received during the inspection operation (S104: NO) but not during the inspection operation (S105: YES), the control device 80 causes the inkjet head 4 to suspend the inspection operation (S106) and perform a recording operation (the "ejection operation" of the present invention) (S107).

[0034] More specifically, 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 motor 87 causes the conveying rollers 6 and 7 to convey the recording paper P in the conveying direction, thereby performing a recording operation on the recording paper P. After the recording operation is completed, the process proceeds to S108.

[0035] In S108, it is determined whether or not there is an abnormal nozzle based on the signal output from the determination circuit 78 during the testing operation. If the testing operation has been completed, it is determined in S108 whether or not there is an abnormal nozzle among all the nozzles 10 of the inkjet head 4. On the other hand, if the testing operation is interrupted in S105, it is determined in S108 whether or not there is an abnormal nozzle among the nozzles 10 that had been driven for testing before the testing operation was interrupted.

[0036] If no abnormal nozzles are present (S108: NO), the process returns to S101. If an abnormal nozzle is present (S108: YES), the control device 80 stores a recovery flag indicating that recovery action is required in the flash memory 84 (S109). Next, the control device 80 determines a recovery action based on the results of the inspection action, stores information about the determined recovery action in the flash memory 84 (S110), and returns to S101.

[0037] 6, a table associating the number N of abnormal nozzles with recovery operations (weak purge, medium purge, strong purge) is stored in flash memory 84. In S110, a recovery operation is determined based on the number N of abnormal nozzles obtained by the inspection operation and the table of FIG.

[0038] On the other hand, if the control device 80 receives a recording command (S102: YES) without receiving a time signal indicating that the predetermined time has arrived (S101: NO), the control device 80 determines whether a recovery flag is stored in the flash memory 84 (S111). If a recovery flag is not stored in the flash memory 84 (S111: NO), the process proceeds to S114. If a recovery flag is stored in the flash memory 84 (S111: YES), the control device 80 controls the cap lifting mechanism 88, the suction pump 72, etc. to perform the recovery operation (suction purge) determined in S110 (S112), erases the recovery flag stored in the flash memory 84 (S113), and then proceeds to S114. As a result, in this embodiment, if the control device 80 determines that an abnormal nozzle exists based on the results of the inspection operation, the recovery operation is performed when the control device 80 receives the first recording command after the inspection operation.

[0039] In S114, the control device 80 starts the recording operation. Thereafter, if the time signal indicating that the predetermined time has arrived has not been received (S116: NO) and the recording operation is completed (S115: YES), the process returns to S101. If the time signal indicating that the predetermined time has arrived is received during the recording operation (S115: NO) (S116: YES), the recording operation continues until the recording operation is completed (S117: NO), and when the recording operation is completed (S117: YES), the process proceeds to S103.

[0040] <Effects> In this embodiment, when a recording command is received during an inspection operation, the inspection operation is interrupted and the recording operation is performed, thereby minimizing the time from when the recording command is received until the recording operation is completed.

[0041] Furthermore, in this embodiment, when the inspection operation is interrupted and the printing operation is performed, if the judgment signal output during the inspection operation up until the printing operation is interrupted indicates the presence of an abnormal nozzle, a recovery operation is performed, thereby allowing the abnormal nozzle to be recovered.

[0042] In this embodiment, the time signal indicating that the predetermined time has arrived is used as an inspection instruction signal that instructs inspection of whether the nozzle 10 is an abnormal nozzle, so that the inspection operation can be performed each time the predetermined time arrives. Furthermore, the timing of the predetermined time (the timing of receiving the time signal indicating that the predetermined time has arrived) is unrelated to the timing of the printing operation.

[0043] Furthermore, unlike the present embodiment, if a time signal indicating a predetermined time is received during a recording operation, the recording operation is interrupted and an inspection operation is performed, which would lengthen the time from when the recording command is received to when the recording operation is completed. In this embodiment, when a time signal indicating a predetermined time is received during a recording operation, the recording operation is completed and then the inspection operation is performed. This makes it possible to minimize the time from when the recording command is received to when the recording operation is completed.

[0044] Furthermore, in this embodiment, if a recovery operation is required during the inspection operation, the recovery operation is performed immediately before the printing operation based on the first received printing command after the inspection operation is completed or interrupted, thereby enabling the printing operation to be performed without any abnormal nozzles.

[0045] Furthermore, in this embodiment, a weak purge, a medium purge, or a strong purge is selectively performed depending on the number of abnormal nozzles, thereby making it possible to perform an appropriate recovery operation depending on the number of abnormal nozzles.

[0046] <Modification> Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims.

[0047] In the above-described embodiment, when a recording command is received during an inspection operation and the inspection operation is interrupted, after the printing operation is completed, it is determined whether or not there is an abnormal nozzle among the nozzles 10 that were driven for inspection during the inspection operation up until the interruption, but this is not limited to this.

[0048] In Modification 1, the control device 80 performs processing in accordance with the flow of FIG. 7. In the flow of FIG. 7, the processing of S101 to S107 and S111 to S117 is the same as in the above-described embodiment. Also, in Modification 1, similar to the above-described embodiment, if it is determined in S104 that the inspection operation is completed (S104: YES), the processing of S108 to S110 is executed. Also, in Modification 1, unlike the above-described embodiment, after the printing operation of S107 is completed, the control device 80 resumes the inspection operation (S201) and returns to S104. In the inspection operation resumed in S201, inspection driving is performed for the nozzles 10 for which inspection driving had not been completed before the interruption.

[0049] As a result, in Modification 1, if a recording command is received during an inspection operation and the inspection operation is interrupted, the inspection operation is resumed after the printing operation is completed. Then, by the inspection operation up until the interruption and the inspection operation after the restart, it is determined whether or not there is an abnormal nozzle among all the nozzles 10 that have been driven for inspection.

[0050] In Modification 1, when the inspection operation is interrupted and the recording operation is performed, the inspection operation is resumed after the recording operation is completed, and inspection driving is performed for the nozzles 10 for which inspection driving had not been completed before the inspection operation was interrupted. This makes it possible to perform inspection driving for each of the multiple nozzles 10 after the recording operation, even when the inspection operation is interrupted.

[0051] Furthermore, in Modification 1, if either the determination signal output during the inspection operation before it was interrupted or the determination signal output during the inspection operation after it is resumed indicates the presence of an abnormal nozzle, a recovery operation is performed, thereby making it possible to recover the abnormal nozzle.

[0052] Furthermore, in Modification 1, the inspection operation is resumed after the completion of the recording operation, and inspection driving is performed only for the nozzles 10 for which inspection driving had not been completed before the inspection operation was interrupted, but this is not limited to this. For example, when the inspection operation is resumed after the completion of the recording operation, in addition to performing inspection driving for the nozzles 10 for which inspection driving had not been completed before the inspection operation was interrupted, inspection driving may be performed again for at least some of the nozzles 10 for which inspection driving had been completed before the inspection operation was interrupted.

[0053] Furthermore, in this embodiment, whether or not a recovery operation is necessary is determined based on the results of both the inspection operation before the printing operation and the inspection operation after the printing operation is completed, and if a recovery operation is necessary, the recovery operation is performed immediately before the printing operation based on the first received printing command after the inspection operation is completed. This makes it possible to perform the printing operation without any abnormal nozzles.

[0054] Furthermore, in the first modification, when a recording command is received during an inspection operation, the inspection operation is interrupted, a recording operation is performed, and the inspection operation is resumed after the recording operation is completed, but the present invention is not limited to this.

[0055] In Modification 2, the control device 80 performs processing according to the flow of FIG. 8. In the flow of FIG. 8, the processing of S101 to S106 and S111 to S117 is the same as in the above-described embodiment. Also, in Modification 1, similar to the above-described embodiment, if it is determined in S104 that the inspection operation is completed (S104: YES), the processing of S108 to S110 is performed. On the other hand, in Modification 1, unlike the above-described embodiment, the control device 80 interrupts the inspection operation in S106, starts the recording operation (S301), and proceeds to the flow of FIG. 9. Also, in Modification 1, unlike the above-described embodiment, if it is determined in S117 that a time signal indicating that a predetermined time has been received (S117: YES), the control device 80 proceeds to the flow of FIG. 9.

[0056] 9 will be described in more detail. First, the control device 80 determines whether the recording operation has been completed (S401). If the recording operation has been completed (S401: YES), the control device 80 starts or resumes the inspection operation (S402) and returns to S104. Here, the inspection operation is started in S402 when, for example, the recording operation started in S114 is completed after it is determined in S117 that a time signal indicating that a predetermined time has been received (S117: YES). The inspection operation is resumed in S402 when, for example, the recording operation started in S301 is completed, or when the recording operation started in S115 or S301 is completed after the inspection operation is interrupted in S407 (described later).

[0057] Until the recording operation is completed (S401: NO), the control device 80 determines whether or not the standby time during the recording operation (hereinafter, sometimes simply referred to as "standby time") has arrived (S403). The standby time is, for example, a standby time provided every time a predetermined number of recording passes are performed, or every time a predetermined number of sheets of recording paper P are recorded, in order to allow the temperature of the inkjet head 4 to drop, which has risen due to driving during a recording pass. The standby time also includes a state in which recording cannot continue due to a paper shortage or an error. If the standby time has not arrived (S403: NO), the process returns to S401.

[0058] Furthermore, when the standby time has arrived (S403: YES), the control device 80 starts or resumes the inspection operation (S404). The inspection operation is started in S404 when, for example, the standby time has arrived for the first time after the start of the recording operation in S301. The inspection operation is resumed in S404 when, for example, the standby time has arrived again after the inspection operation was interrupted in S407 (described later).

[0059] If the waiting time continues (S405: NO) and the inspection operation is not completed (S406: NO), the inspection operation continues. If the waiting time ends during the inspection operation (S405: YES), the control device 80 interrupts the inspection operation (S407) and returns to S401.

[0060] If the inspection operation is completed (S406: YES) before the waiting time expires (S405: NO), the control device 80 determines whether or not there is an abnormal nozzle (S408), as in S108. If there is no abnormal nozzle (S408: NO), the process proceeds to S412. If there is an abnormal nozzle (S408: YES), the control device 80 determines a recovery operation, as in S110, and stores the result in the flash memory 84 (S409).

[0061] Next, the control device 80 determines whether the remaining waiting time Tr is equal to or greater than the time Tk required for the recovery operation determined in S409 (S410). Here, if the waiting time is due to a paper shortage, for example, and the length cannot be estimated, the control device 80 performs the determination in S410 by setting the estimated time required for replacing the recording paper P as the remaining waiting time Tr.

[0062] If the remaining waiting time Tr is equal to or greater than the time Tk required for the recovery operation determined in S409 (S410: YES), the control device 80 performs the recovery operation as in S112 (S411) and proceeds to S412. In S412, it is determined whether the recording operation started in S301 or S113 has been completed. The recording operation is continued until the recording operation started in S301 or S113 is completed (S412: NO), and when the recording operation is completed (S412: YES), the process returns to S101.

[0063] If the remaining waiting time Tr is less than the time Tk required for the recovery operation determined in S409 (S410: NO), after the current waiting time has ended and the recording operation has resumed, the process waits until the next waiting time has elapsed or until the recording operation has been completed (S413: NO, S414: NO), and then resumes and continues the recording operation. When the next waiting time has elapsed (S413: YES), the process returns to S410. When the recording operation has been completed (S414: YES), the process stores a recovery flag in flash memory 84 (S415), as in S109, and returns to S101.

[0064] In the second modification, when a recording command is received in the middle of an inspection operation and the inspection operation is interrupted, the interrupted inspection operation can be resumed by utilizing the waiting period provided in the middle of the recording operation.

[0065] In addition, in variant example 2, if a recording command is received during an inspection operation and the inspection operation is interrupted, and if there is sufficient waiting time during the recording operation, a recovery operation can be performed as necessary after the inspection operation is completed.

[0066] In addition, in Modification 2, when a time signal indicating that a predetermined time has arrived is received during a recording operation, if there is a waiting period during the recording operation, an inspection operation is performed during the waiting period. This makes it possible to minimize the time from when a recording command is received until the recording operation is completed, while still performing the inspection operation.

[0067] In addition, in variant example 2, when a time signal indicating that a predetermined time has arrived is received during a recording operation, if the above-mentioned waiting time is sufficient, a recovery operation can be performed as necessary after the inspection operation is completed.

[0068] In addition, in the second modification, after the inspection operation is completed during the standby time, if the remaining time Tr of the standby time is equal to or greater than the time Tk required for the recovery operation, the recovery operation is performed, but this is not limited to this. For example, when the inspection operation is completed during the standby time, a recovery flag may be stored in the flash memory 84 regardless of the remaining time of the standby time, and if the recovery flag is stored in the flash memory 84 when the first recording command is received after the inspection operation, the recovery operation may be performed.

[0069] Furthermore, in the above-described embodiment, the time signal indicating that a predetermined time has arrived is received as an inspection instruction signal instructing that the nozzle 10 be inspected to determine whether it is an abnormal nozzle, but this is not limited to this.

[0070] 10, in the third modification, the printer 100 is configured such that a timer 101 is provided in place of the clock unit 70 in the printer 1. The timer 101 outputs an elapsed time signal indicating the elapsed time since it was reset.

[0071] In the third modification, when the printer 100 is first powered on, the control device 80 causes an inspection operation to be performed, and when the inspection operation is completed, the control device 80 resets the timer 101. Thereafter, as will be described later, when the inspection operation is completed or interrupted, the control device 80 resets the timer 101.

[0072] In Modification 3, the control device 80 performs processing in accordance with the flow of Fig. 11. To explain in more detail, the control device 80 waits while it has not received an elapsed time signal (an "inspection instruction signal" of the present invention) from the timer 101 indicating that a predetermined time has elapsed (S501: NO) and has not received a recording command (S102: NO).

[0073] When an elapsed time signal indicating that a predetermined time has elapsed is received (S501: YES), the control device 80 executes the processes of S103 to S106, as in the above-described embodiment. Furthermore, when it is determined in S104 that the inspection operation has been completed (S104: YES), the control device 80 resets the timer 101 (S502) and then executes the processes of S108 to S110. However, unlike the above-described embodiment, after suspending the inspection operation in S106, the control device 80 resets the timer 101 (S503) and then executes the processes of S107 to S110.

[0074] As a result, in Modification 3, the timer 101 is reset each time the inspection operation is completed or interrupted. That is, the elapsed time signal output from the timer 101 indicates the time elapsed since the last inspection operation was performed. In Modification 3, the inspection operation corresponds to the "predetermined operation" of the present invention.

[0075] On the other hand, when a recording command is received while an inspection operation is not being performed (S102: YES), the control device 80 executes the processes of S111 to S115, as in the above-described embodiment. Furthermore, the control device 80 continues the recording operation as long as it determines in S115 that the recording operation is not complete (S115: NO) and has not received an elapsed time signal indicating that a predetermined time has elapsed (S504: NO). Then, as in the above-described embodiment, when the recording operation is completed (S115: YES), the process returns to S101. If, during the recording operation (S115: NO), the control device 80 receives an elapsed time signal indicating that a predetermined time has elapsed (S504: YES), the process proceeds to S117.

[0076] In the third modification, an elapsed time signal indicating that a predetermined time has elapsed since the last inspection operation (since the inspection operation was completed or interrupted) is received as an inspection instruction signal, so that the inspection operation can be performed each time the predetermined time has elapsed. Furthermore, the timing at which the predetermined time elapses since the last predetermined operation is performed is unrelated to the timing of the ejection operation. Therefore, a recording command may be received during the inspection operation. Therefore, in the third modification, when a recording command is received during the inspection operation, the inspection operation is interrupted and a recording operation is performed. This makes it possible to minimize the time from when the recording command is received to when the recording operation is completed.

[0077] In addition, in Modification 3, as in the above-described embodiment, an example has been described in which an elapsed time signal indicating that a predetermined time has elapsed is received as an inspection instruction signal in a configuration in which the inspection operation is not resumed after being suspended, but this is not limiting. For example, as in Modifications 1 and 2, in a configuration in which the inspection operation is resumed after being suspended, an elapsed time signal indicating that a predetermined time has elapsed may be received as an inspection instruction signal. In this case, for example, in the flows of FIGS. 7 to 9, instead of the determinations of S101 and S116, the same determinations as in S501 and S504 may be made, and when it is determined in S104 and S406 that the inspection operation has been completed, the timer 101 may be reset.

[0078] In addition, in the third modification, the elapsed time signal output from the timer 101 indicates the time elapsed since the inspection operation was completed or interrupted, but this is not limiting. The elapsed time signal output from the timer 101 may indicate, for example, the time elapsed since another predetermined operation, such as a recovery operation, was last performed.

[0079] In the above example, the inspection instruction signal unrelated to the timing of the recording operation was either a time signal indicating that a predetermined time had arrived or an elapsed time signal indicating that a predetermined time had elapsed since the last predetermined operation was performed, but this is not limiting. The inspection instruction signal may be another signal unrelated to the timing of the recording operation.

[0080] Furthermore, in the above-described embodiment, when a time signal indicating that a predetermined time has arrived is received during recording, an inspection operation based on the time signal is performed after the recording operation is completed, but this is not limited to this.

[0081] In the fourth modification, the control device 80 performs processing according to the flow of FIG. 12. In the flow of FIG. 12, the processing of S101 to S114 is the same as in the above-described embodiment. Furthermore, in the fourth modification, unlike the above-described embodiment, after starting the recording operation in S114, the recording operation continues until the recording operation is completed regardless of whether a time signal indicating that the predetermined time has been received (S115: NO), and when the recording operation is completed (S115: YES), the process returns to S101. As a result, in the fourth modification, if a time signal indicating that the predetermined time has been received during the recording operation, the inspection operation based on the time signal is not performed, and the inspection operation is performed when the next time signal indicating that the predetermined time has been received.

[0082] In the fourth modification, when an inspection operation is performed at each predetermined time, if a time signal indicating that the predetermined time has arrived is received during a recording operation, the inspection operation based on the time signal is not performed, and a recovery operation is performed when the next time signal indicating that the predetermined time has arrived is received. This makes it possible to minimize the time from when a recording command is received until the recording operation is completed. Also, the inspection operation can be performed when the next predetermined time arrives.

[0083] In the above example, the recovery operation is performed when the first recording command is received after the inspection operation or during a standby period during recording, but this is not a limitation. For example, if the printer is capable of selectively recording in either high-image-quality mode or low-image-quality mode, the recovery operation may be performed when the printer receives a recording command instructing recording in high-image-quality mode for the first time after the inspection operation and a recovery flag is stored in flash memory 84. Alternatively, the recovery operation may be performed immediately when it is determined in S108 or S408 that a malfunctioning nozzle exists. Alternatively, the recovery operation may be notified to the user at any time after the inspection operation if a malfunctioning nozzle exists, allowing the user to select whether or not to perform the recovery operation, and the recovery operation may be performed if the user selects to perform the recovery operation.

[0084] In the above example, the recovery operation is selectively performed among weak, medium, and strong purging depending on the number of abnormal nozzles. However, this is not limiting. For example, the recovery operation may be selectively performed among weak, medium, and strong purging depending on conditions other than the number of abnormal nozzles, such as the distribution of abnormal nozzles. Alternatively, if abnormal nozzles are present, a uniform suction purging may be performed regardless of the number of abnormal nozzles. Alternatively, for example, the recovery operation may be performed by flushing the inkjet head 4, which ejects ink from at least the abnormal nozzles. In this case, the inkjet head 4 doubles as the "recovery means" of the present invention. Alternatively, the recovery operation may be performed by both flushing and suction purging. In this case, the maintenance unit 8 and the inkjet head 4 correspond to the "recovery means" of the present invention.

[0085] Furthermore, in the above example, suction purging was performed as the purging, but this is not limited to this. For example, a pressure pump may be provided midway along the tube 15 connecting 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 plurality of nozzles 10 covered with 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 so-called pressure purging. In this case, the pressure pump corresponds to the "recovery means" of the present invention.

[0086] Furthermore, during purging, both suction by the suction pump 72 and pressurization by the pressurization pump may be performed. In this case, the maintenance unit 8 and the pressurization pump correspond to the "recovery means" of the present invention.

[0087] Furthermore, in the above embodiment, the test drive is performed on all of the nozzles 10 of the inkjet head 4, but this is not limiting. 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 based on the determination signal output from the determination circuit 78 during the test drive.

[0088] Furthermore, 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 this.

[0089] 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 an area 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.

[0090] Alternatively, for example, as described in Patent Publication No. 4929699, a voltage detection circuit (the "signal output unit" of the present invention) that detects changes in voltage when ink is ejected from the nozzles can be connected to the 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.

[0091] 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 to eject ink, a second applied voltage is applied to drive the heater so that ink is not ejected, and a signal indicating whether or not the nozzle 10 is an abnormal nozzle may be output based on the change in temperature detected by the temperature detection element during the period from when the second applied voltage was applied until a predetermined time has elapsed.

[0092] Furthermore, in the above example, the signal output unit outputs a signal in accordance with whether or not ink is ejected from the nozzle 10, but this is not limited to this. For example, a signal output unit may be provided that outputs a signal in accordance with whether or not an abnormality other than the nozzle 10 not ejecting ink occurs, and whether or not the nozzle 10 is an abnormal nozzle may be determined based on the signal from the signal output unit. An abnormality other than the nozzle not ejecting ink may be, for example, an abnormality in the ink ejection direction.

[0093] 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.

[0094] Although the above description has been given of an example in which the present invention is applied to a printer that ejects ink from nozzles to record on recording paper P, 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, outdoor advertising sheets, cases for mobile devices such as smartphones, cardboard, and resin materials. 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]

[0095] 1. Printer 4 Inkjet head 8 Maintenance Unit 10 nozzles 70 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 100 printers 101 Timer

Claims

1. a liquid ejection head having a plurality of nozzles that eject liquid onto an ejection receiving medium; a signal output unit that outputs a determination signal according to 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 a discharge instruction signal that instructs the liquid discharge head to perform a discharge operation that causes the liquid to be discharged from the plurality of nozzles, and an inspection instruction signal that is a signal that is received regardless of the timing of the discharge operation and that instructs the liquid discharge head to inspect whether or not the nozzle is an abnormal nozzle; When the ejection instruction signal is received, the liquid ejection head is caused to perform the ejection operation; When the inspection instruction signal is received, the liquid ejection head is caused to perform an inspection operation in which the inspection driving is performed sequentially for at least two nozzles out of the plurality of nozzles, When the ejection instruction signal is received during the inspection operation, the liquid ejection head is caused to interrupt the inspection operation and perform the ejection operation; If there is a waiting period during the ejection operation that is performed by the liquid ejection head after the inspection operation has been interrupted, A liquid ejection device characterized in that, during the waiting period, the liquid ejection head is caused to resume the inspection operation, and the inspection drive is performed at least for the nozzles for which the inspection drive had not been completed before the ejection operation was interrupted.

2. recovery means for performing a recovery operation to discharge ink from the nozzles; The liquid ejection device described in claim 1, characterized in that during the waiting period, if at least one of the judgment signal output from the signal output unit during the inspection operation after completion of the inspection operation until it is interrupted, and the judgment signal output from the signal output unit during the inspection operation after it is resumed, indicates the presence of an abnormal nozzle, the recovery means is caused to perform the recovery operation.

3. a clock unit that outputs a time signal indicating the time; 3. The liquid ejection device according to claim 1, wherein the inspection instruction signal is the time signal indicating that a predetermined time has arrived.

4. a timer that outputs an elapsed time signal indicating the time that has elapsed since the liquid ejection device last performed a predetermined operation; 3. The liquid ejection device according to claim 1, wherein the inspection instruction signal is an elapsed time signal indicating that the elapsed time has reached a predetermined time.

5. a liquid ejection head having a plurality of nozzles that eject liquid onto an ejection receiving medium; a signal output unit that outputs a determination signal according to 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 a discharge instruction signal that instructs the liquid discharge head to perform a discharge operation that causes the liquid to be discharged from the plurality of nozzles, and an inspection instruction signal that is a signal that is received regardless of the timing of the discharge operation and that instructs the liquid discharge head to inspect whether or not the nozzle is an abnormal nozzle; When the ejection instruction signal is received, the liquid ejection head is caused to perform the ejection operation; When the inspection instruction signal is received, the liquid ejection head is caused to perform an inspection operation in which the inspection driving is performed sequentially for at least two nozzles out of the plurality of nozzles, A liquid ejection device characterized in that, when the inspection instruction signal is received during the ejection operation and a waiting period exists during the ejection operation, the ejection operation is continued and the liquid ejection head is caused to perform the inspection operation during the waiting period.

6. recovery means for performing a recovery operation to discharge ink from the nozzles; A liquid ejection device as described in claim 5, characterized in that during the waiting period, after the inspection operation is completed, when the judgment signal received from the signal output unit during the inspection operation indicates that an abnormal nozzle exists, the recovery means is caused to perform the recovery operation.

7. recovery means for performing a recovery operation to discharge ink from the nozzles; The control device When the ejection instruction signal is received for the first time after the inspection operation is completed or interrupted, If the determination signal output from the signal output unit during the inspection operation indicates that an abnormal nozzle exists, 6. The liquid ejection apparatus according to claim 1, wherein the recovery means performs the recovery operation, and then the liquid ejection head performs the ejection operation.

8. The control device 7. The liquid ejection apparatus according to claim 2, wherein the recovery operation is performed by the recovery means in response to the determination signal.

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