Liquid dispensing device

Abstract

To keep a wasteful exhaust of a liquid as low as possible in a liquid discharge device.SOLUTION: A printer performs a checkup derive (S201, S202 : YES) when time becomes predetermined on a standby time. The printer stores flag information which indicates that an abnormal nozzle is present (S206) when a judgement signal outputted on a checkup drive standby time indicates that the abnormal nozzle is present (S205 : YES). Further, the printer performs flashing that is a part of recovery action (S208). And, afterwards, the printer suction purge that is the portion excluding an above-mentioned part of the recovery action is performed in the case where the flag information is stored when its the power supply turns on.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] As an example of a liquid ejection device that ejects liquid from nozzles, Patent Document 1 describes a printer that ejects ink from nozzles to record on paper. The printer in Patent Document 1 performs a maintenance operation, including purging, at a predetermined time, for example, by driving a pump to apply pressure and forcibly expelling ink from the head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-61673 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 predetermined time. However, if there is a long period of time between the time and when the printer starts recording on paper, the ink in the head may thicken during this period, making it necessary to perform another maintenance operation immediately before recording on paper. In this case, the ink discharged during the maintenance operation performed at the predetermined time ends up being wasted.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid ejection device that can minimize the amount of wasted liquid discharged. [Means for solving the problem]

[0006] A liquid ejection device of the present invention includes a liquid ejection head having a nozzle that ejects 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 check whether or not the nozzle is an abnormal nozzle that is abnormal in ejecting liquid, recovery means that performs a recovery operation to discharge liquid from the nozzle, a memory unit, and a control device, and the control device controls the liquid ejection head. Out Head to front Chronicles When a first signal, which is different from an ejection instruction signal that instructs the nozzle to eject liquid toward the ejection medium, is received, the inspection drive is performed, and when a second signal, which is the ejection instruction signal, is received, the recovery means is caused to perform the recovery operation according to the result of the inspection drive that was performed in response to receiving the first signal. 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 determination signal indicating whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to check whether or not the nozzle is an abnormal nozzle that is abnormal in ejecting liquid, recovery means that performs a recovery operation to discharge liquid from the nozzle, a clock unit, a memory unit, and a control device, and the control device comprises: clock When the unit receives a first signal corresponding to the clocking of a predetermined time of day, the unit causes the inspection drive to be performed, and when the unit receives a second signal different from the first signal, the unit causes the recovery means to perform the recovery operation according to the result of the inspection drive performed when the first signal was received. 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 determination signal indicating whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to check whether or not the nozzle is an abnormal nozzle that is abnormal in ejecting liquid, recovery means that performs a recovery operation to discharge liquid from the nozzle, a clock unit, a memory unit, and a control device, and the control device comprises: clock When the timekeeping unit measures a predetermined time in one day, the inspection drive is performed, and the liquid discharge Out Head to front ChroniclesWhen an ejection instruction signal instructing to eject liquid toward the ejection receiving medium is received from the nozzle, the recovery means is caused to perform the recovery operation according to the result of the test drive. [Effects of the Invention]

[0007] If the inspection drive is performed when the first signal is received, and if the judgment signal indicates the presence of an abnormal nozzle, then, unlike the present invention, a recovery operation is immediately performed, there is a risk that the liquid inside the liquid ejection head will thicken during the long period between receiving the first signal and receiving the second signal. In this case, it is necessary to perform the recovery operation again when the second signal is received, and as a result, the discharge of liquid by the recovery operation performed when the first signal is received will be wasted.

[0008] In this invention, when a first signal is received, an inspection drive is performed, and if the determination signal indicates the presence of an abnormal nozzle, flag information is stored. Then, when a second signal is received, if the flag information has been stored, a recovery operation is performed. This prevents the above-mentioned unnecessary discharge of liquid, even if there is a long period between receiving the first signal and receiving the second signal. [Brief explanation of the drawings]

[0009] [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. 1(a) is a diagram showing the change in voltage value of the detection electrode when ink is ejected from the nozzle, and FIG. 1(b) 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. [Figure 5]10A is a flowchart showing the flow of processing when power is supplied to at least the control device and the clock unit, and FIG. 10B is a diagram for explaining stored temperature range information. [Figure 6] 5(a) is a flowchart showing the flow of process A in FIG. [Figure 7] 6 is a flowchart showing the flow of process B in FIG. 5(a). [Figure 8] 10 is a flowchart showing the flow of processing during recording. [Figure 9] 10 is a flowchart corresponding to FIG. 5(a) of Modification 1. [Figure 10] 10 is a flowchart corresponding to FIG. 5(a) of Modification 2. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present invention will now be described.

[0011] <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, a maintenance unit 8, etc.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] In this embodiment, it is possible to selectively perform one of several types of suction purge, each with a different ink discharge amount. The ink discharge amount differs between the several types of suction purge, 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] On the other hand, when no ink is ejected from the nozzle 10, as shown in Fig. 3(b), during the driving period Td of the inkjet head 4, the potential of the detection electrode 76 hardly changes from the potential Va. Therefore, a threshold value Vt (Va < Vt < Vb) is set in the determination circuit 78 to distinguish between these cases. Then, the determination circuit 78 compares the maximum potential of the voltage signal output from the detection electrode 76 with the threshold value Vt during the driving period Td of the inkjet head 4 and outputs a determination signal according to the determination result. In this embodiment, the combination of the detection electrode 76, the high-voltage power supply circuit 77, the resistor 79, and the determination circuit 78 corresponds to the "signal output unit" of the present invention. And this signal output unit outputs a determination signal according to whether the nozzle 10 is an abnormal nozzle from which no ink is ejected.

[0024] 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.

[0025] <Printer electrical configuration> Next, the electrical configuration of the printer 1 will be described. As shown in FIG. 4, the printer 1 includes a control device 80. The control device 80 includes a CPU (Central Processing Unit) 81, a ROM (Read Only Memory) 82, a RAM (Random Access Memory) 83, a flash memory 84, and an ASIC (Application Specific Integrated Circuit) 85. The control device 80 controls the operation of a carriage motor 86, inkjet head 4, a transport motor 87, a cap lifting mechanism 88, a suction pump 72, a high-voltage power supply circuit 77, a driver IC 89, and the like. In this embodiment, the control device 80 controls the driver IC 89 to control the inkjet head 4. A determination signal is also input to the control device 80 from a determination circuit 78.

[0026] In addition to the components described above, the printer 1 also includes a display unit 69, an operation unit 70, a clock unit 68, a temperature sensor 67, and a battery 66. The display unit 69 is, for example, a liquid crystal display provided on the housing of the printer 1. The control device 80 controls the display unit 69 to display information necessary for the operation of the printer 1. The operation unit 70 is, for example, buttons provided on the housing of the printer 1, a touch panel provided on the display unit 69, etc. The user can input signals to the control device 80 by operating the operation unit 70.

[0027] In this embodiment, the operation unit 70 also 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 operation unit 70 outputs a power-on signal (the "second signal" of the present invention) indicating that the printer 1 has been turned on, and the control device 80 receives this power-on signal.

[0028] The clock unit 68 keeps time, and the control unit 80 receives a time signal indicating the time (a "first signal" of the present invention) from the clock unit 68. The temperature sensor 67 detects, for example, the temperature of the inkjet head 4. The control unit 80 receives a temperature signal indicating the temperature from the temperature sensor 67.

[0029] The battery 66 is connected to at least the control device 80 and the clock unit 68. Power is supplied to the printer 1 from an outlet (not shown), and at this time the battery 66 is charged. When the printer 1 is unplugged, power is supplied from the battery 66 to at least the control device 80 and the clock unit 68.

[0030] 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.

[0031] <Standby control> Next, the control by the control device 80 during standby when no recording or the like is performed on the recording paper P in the printer 1 will be described. In the printer 1, during the standby, the control device 80 performs processing in accordance with the flow of FIG. 5(a). Here, the flow of FIG. 5(a) is continued, for example, when the power supply to the printer 1 is started by inserting a power plug into the printer 1 for the first time, and thereafter, while the power supply from the power plug or the battery 66 to the control device 80 and the clock unit 68 is being performed.

[0032] More specifically, regarding the flow of FIG. 5(a), the control device 80 indicates that the time signal received from the clock unit 68 is not a predetermined time (S101: NO), and the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 is the same as the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 when the inspection drive described later was last performed (S102: NO). While not receiving the power-on signal (S103: NO), it waits.

[0033] Here, in the flash memory 84, for example, information on temperature ranges 1 to 4 as shown in FIG. 5(b) is stored. T1, T2, and T3 in FIG. 5(b) are in the magnitude relationship of T1 < T2 < T3. Further, the control device 80 stores the information on the temperature T indicated by the temperature signal received from the temperature sensor 67 when performing the inspection drive described later in the flash memory 84. The control device 80 makes the determination of S102 based on the temperature T indicated by the temperature signal received from the temperature sensor 67, the information on the temperature ranges in FIG. 5(b) stored in the flash memory 84, and the temperature T stored during the inspection drive.

[0034] In this embodiment, among the temperature ranges shown in FIG. 5(b), the temperature range including the temperature T indicated by the temperature signal received from the temperature sensor 67 when performing the inspection drive described later corresponds to the "first temperature range" of the present invention. Further, in this embodiment, thereafter, when the temperature T indicated by the temperature signal received from the temperature sensor 67 becomes a temperature included in a temperature range different from the first temperature range, the different temperature range corresponds to the "second temperature range" of the present invention.

[0035] When the time signal received from the clock unit 68 indicates that it is the predetermined time (S101: YES), the control device 80 executes process A (S102). In this embodiment, the time signal indicating that it is the predetermined time corresponds to the "first signal" of the present invention.

[0036] Furthermore, when the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 becomes a different temperature range from the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 when the test driving described below was last performed (S102: YES), the control device 80 also executes process A (S102). Furthermore, when a power-on signal is received (S103: YES), the control device 80 executes process B (S104).

[0037] <Process A> Next, the process A will be described. As shown in Fig. 6, in the process A, the control device 80 first executes an inspection process (S201). In the inspection process, the control device 80 transmits a drive signal to the driver IC 89 to perform an inspection drive that drives the inkjet head 4 so as to eject ink from each of the multiple nozzles 10 in turn.

[0038] Next, the control device 80 determines whether or not the test drive has actually been performed by the test process of S201 (S202). Here, the case where the test drive is actually performed by the test process is, for example, when the power outlet is plugged in and the inkjet head 4 can be driven for test using power supplied from the outlet. On the other hand, the case where the test drive is not actually performed by the test process is, for example, when the power outlet is unplugged and the inkjet head 4 cannot be driven for test.

[0039] If test driving was not actually performed by the test process (S202: NO), the process returns to the flow of FIG. 5(a). If test driving was actually performed by the test process (S202: YES), the control device 80 updates the test history information (S203). More specifically, the flash memory 84 stores test history information, which is information about the time when the test driving was last performed. In S203, the control device 80 updates the information about the time when the test driving was last performed, which is stored in the flash memory 84, based on the time signal from the clock unit 68.

[0040] Next, the control device 80 resets the variable C to 0 (S204). The variable C corresponds to the number of sheets of recording paper P on which recording has been performed since the last test driving was performed.

[0041] Next, if the determination signal output from the determination circuit 78 during the test drive indicates that no abnormal nozzles exist (S205: NO), the process returns to the flow of Fig. 5(a). On the other hand, if the determination signal output from the determination circuit 78 during the test drive indicates that an abnormal nozzle exists (S205: YES), the control device 80 stores flag information indicating the existence of an abnormal nozzle in the flash memory 84 (S206).

[0042] Next, the control device 80 stores type information indicating the type of suction purge to be performed in the flash memory 84 (S207). To explain the process in detail, in S207, the control device 80 stores, as the type information, information on the suction purge that discharges more ink the greater the number of nozzles 10 that are indicated to be abnormal by the determination signals output from the determination circuit 78 during the test drive.

[0043] Next, the control device 80 executes a flushing process (S208), and the process returns to the flow of Fig. 5(a). In the flushing process, the control device 80 controls the driver IC 89 to cause the inkjet head 4 to perform flushing, which causes ink to be discharged from the nozzles 10. At this time, the control device 80 may cause ink to be discharged only from the abnormal nozzle, or may cause ink to be discharged from all the nozzles 10 of the inkjet head 4, including the abnormal nozzle.

[0044] <Process B> Next, a description will be given of process B. As shown in Fig. 7, in process B, first, it is determined based on the above-mentioned test history information whether or not test driving was performed at the last predetermined time before the power was turned on (S301).

[0045] If the test drive was performed at the last predetermined time before the power was turned on (S301: YES), the control device 80 then determines whether the above flag information is stored in the flash memory 84 (S302).

[0046] If the flag information is not stored in the flash memory 84 (S302: NO), the process returns to the flow of FIG. 5(a). If the flag information is stored in the flash memory 84 (S302: YES), the control device 80 determines the type of suction purge based on the type information (S303) and executes the purge process (S304). In the purge process of S304, the control device 80 performs the suction purge determined in S303. Then, after the purge process of S304 is completed, the control device 80 erases the flag information stored in the flash memory 84 (S305), and the process returns to the flow of FIG. 5(a).

[0047] If test driving was not performed at the last predetermined time before the power was turned on (S301: NO), the control device 80 then executes the same test process as S201 (S306), updates the test history information as in S203 and S204 (S307), and resets the variable C to 0 (S308). Here, process B is a process that is performed when the power is turned on, i.e., a process that is performed while power is being supplied from the outlet. Therefore, when the test process of S306 is executed, test driving is performed on the inkjet head 4.

[0048] Next, if the determination signal output from the determination circuit 78 during the test drive performed by the test process of S304 indicates that there are no abnormal nozzles (S309: NO), the control device 80 returns to the flow of Figure 5(a).

[0049] If the determination signal indicates that there is an abnormal nozzle (S309: YES), the control device 80 then determines the type of suction purge to perform based on the determination signal output from the determination circuit 78 during the test drive performed by the test process of S304 (S310). In S310, the control device 80 determines the suction purge to perform with a larger amount of ink discharge the more the number of nozzles 10 indicated by the determination signal to be abnormal increases.

[0050] Next, the control device 80 executes the flushing process similar to S208 (S311), and then executes the purging process (S312). In the purging process of S312, the control device 80 executes the suction purging determined in S310. After the purging process of S312 is completed, the process returns to the flow of FIG. 5(a).

[0051] 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 addition, in this embodiment, the combination of flushing and suction purging corresponds to the "recovery operation" of the present invention, with flushing corresponding to "a part of the recovery operation" of the present invention and suction purging corresponding to "the remaining part of the recovery operation excluding a part" of the present invention.

[0052] <Recording control> Next, we will explain the control when recording on recording paper P in the printer 1. In the printer 1, when a recording command ("ejection command" of the present invention) instructing to record on recording paper P is received, the control device 80 performs processing according to the flow of FIG.

[0053] 8 in more detail, the control device 80 first executes a paper feed process (S401). In the paper feed process, the control device 80 controls a paper feed mechanism (not shown) and a conveyance motor 87 to cause the paper feed mechanism to supply recording paper P, and also causes conveyance rollers 6 and 7 to convey the recording paper P to a position where an area of ​​the recording paper P on which an image is to be recorded in the first recording pass faces the multiple nozzles 10 of the inkjet head 4.

[0054] Next, the control device 80 executes a recording pass process (S402). In the recording pass process, the control device 80 controls the carriage motor 86 to move the carriage 2 in the scanning direction, and controls the driver IC 89 to drive the multiple drive elements 22a, thereby causing the inkjet head 4 to perform a recording pass in which ink is ejected from the multiple nozzles 10 toward the recording paper P.

[0055] Next, if recording on one sheet of recording paper P is not complete (S403: NO), the control device 80 executes a conveying process (S404) and returns to S402. In the conveying process, the control device 80 controls the conveying motor 87 to cause the conveying rollers 6 and 7 to convey the recording paper P a predetermined distance.

[0056] If the recording of an image on one sheet of recording paper P is complete (S403: YES), the control device 80 executes a paper discharge process (S405) and increments the value of the variable C by 1 (S406). In the paper discharge process of S405, the control device 80 controls the conveyance motor 87 to cause the conveyance rollers 6 and 7 to discharge the recording paper P on which recording has been completed.

[0057] If there is recording data to be recorded on the next recording paper P (S407: YES), the process returns to S401. If there is no recording data (S407: NO), and the value of the variable C is less than the predetermined value Ct (S408: NO), the process ends.

[0058] If the value of the variable C is equal to or greater than the predetermined value Ct (S408: YES), the control device 80 executes the processes of S409 to S415, which are the same as S306 to S312, and then ends the process.

[0059] <Effects> Consider a case where, when a time signal indicating a predetermined time is received, a test drive is performed, and if the determination signal output from the determination circuit 78 during the test drive indicates the presence of an abnormal nozzle, a recovery operation is immediately performed, unlike the present invention. In this case, if there is a long period between receiving the time signal indicating the predetermined time and receiving the power-on signal, there is a risk that the ink in the inkjet head 4 will thicken during this period. In this case, it is necessary to perform the recovery operation again when the power-on signal is received, and as a result, the discharge of ink by the recovery operation performed when the time signal indicating the predetermined time is received will be wasted.

[0060] In contrast, in this embodiment, when a time signal indicating that a predetermined time has arrived is received, a test drive is performed, and if the determination signal output from the determination circuit 78 during the test drive indicates the presence of an abnormal nozzle, flag information is stored. Then, when a power-on signal is subsequently received, if the flag information has been stored, a recovery operation is performed. As a result, even if there is a long period of time between receiving the time signal indicating the predetermined time and receiving the power-on signal, the above-mentioned unnecessary ink ejection is not performed.

[0061] Furthermore, if the test drive is to be performed at a predetermined time, it is desirable to do so at night, when the user is unlikely to use the printer 1. However, even small sounds can be loud at night, so performing the recovery process immediately after the test drive can result in noise. Therefore, the recovery process is not performed immediately after the test drive, but is instead performed when the power-on signal is received when the user uses the printer 1, thereby solving the noise problem.

[0062] Furthermore, in this embodiment, when a time signal indicating a predetermined time is received, an inspection drive is performed, and information on the type of suction purge is stored based on the judgment signal output from the judgment circuit 78 during the inspection drive. Then, when a power-on signal is subsequently received, if the flag information has been stored, the stored suction purge is performed. This makes it possible to perform an appropriate suction purge depending on the number of abnormal nozzles, etc.

[0063] Furthermore, in this embodiment, when a time signal indicating a predetermined time is received, an inspection drive is performed, and if the determination signal output from the determination circuit 78 during this inspection drive indicates the presence of an abnormal nozzle, flushing, which is part of the recovery operation, is performed. Then, when a power-on signal is subsequently received, suction purging, which is the remaining part of the recovery operation excluding the above-mentioned part, is performed. This makes it possible to shorten the time required for the recovery operation to be performed when the power-on signal is received.

[0064] Furthermore, as described above, if the predetermined time is set during a time period such as nighttime, even a small sound may be perceived as noise by the user. When performing purging, which drives the suction pump 72, and flushing, which does not drive the suction pump 72, as recovery operations, the purging, which drives the suction pump 72, is louder than the flushing, which does not drive the suction pump 72. Therefore, only the flushing is performed at the predetermined time (immediately after the inspection drive). This makes it less likely that the user will perceive the noise.

[0065] In addition, in this embodiment, the inspection drive is performed at a predetermined time, so that the inspection drive can be performed, for example, at a time when the user does not frequently use the printer 1. Times when the user does not frequently use the printer 1 include, for example, at night, during a lunch break, or early in the morning. The user may also set the predetermined time according to their usage cycle.

[0066] Furthermore, when recording on a large number of sheets of recording paper P, paper dust generated from the recording paper P may accumulate inside the nozzle 10, causing the nozzle to become abnormal. Therefore, in this embodiment, when the number of sheets of recording paper P recorded by the inkjet head 4 since the last test drive reaches a predetermined number (when C≧Ct), the test drive is performed again. This makes it possible to accurately identify abnormal nozzles.

[0067] Furthermore, in this embodiment, when the number of sheets of recording paper P on which the inkjet head 4 has recorded reaches a predetermined number while recording is being performed on a plurality of sheets of recording paper P, the test drive is performed again after recording is completed on all of the sheets of recording paper P. This makes it possible to prevent recording from being interrupted even when the number of sheets of recording paper P on which the inkjet head 4 has recorded reaches a predetermined number while recording is being performed on a plurality of sheets of recording paper P.

[0068] Furthermore, when the temperature of the inkjet head 4 changes significantly, the viscosity of the ink inside the nozzle 10 changes, which can change the state of whether the nozzle is abnormal or not. Therefore, in this embodiment, when the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 becomes a different temperature range from the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 when the test drive was last performed, the test drive is performed again. This makes it possible to accurately identify the abnormal nozzle.

[0069] Furthermore, if the printer 1 is unplugged when the specified time arrives and power is being supplied from the battery 66 to the control device 80, the inspection process is executed but the inspection drive is not performed. Furthermore, if the battery 66 is out of power, the inspection process is not executed even when the specified time arrives, and naturally the inspection drive is not performed either.

[0070] Therefore, in this embodiment, when a power-on signal is received, if test drive was not performed at the last specified time before the power-on signal was received, test drive is performed, which makes it possible to identify abnormal nozzles and perform the necessary recovery operations.

[0071] <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.

[0072] In the above embodiment, when the control device 80 receives a power-on signal during standby, the control device 80 executes the process B, but the present invention is not limited to this.

[0073] In variant 1, as shown in FIG. 9, the control device 80 waits while the time signal received from the clock unit 68 does not indicate that it is the specified time (S101: NO), the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 is the same as the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 when the test drive described below was last performed (S102: NO), and a recording command is not received (S501: NO).

[0074] Then, as in the above-described embodiment, when the time signal received from the clock unit 68 indicates that it is a predetermined time (S101: YES), and when the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 becomes a temperature range different from the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 when the test drive described below was last performed (S102: YES), the control device 80 executes process A (S104).

[0075] On the other hand, when a recording command is received (S501: YES), if the received recording command is the first received recording command after process A, including inspection process, is executed upon reception of a time signal indicating that the predetermined time has arrived (S502: YES), process B, similar to the above-described embodiment, is executed (S105), and then recording process is executed (S503). Also, if the received recording command is not the first received recording command after process A, including inspection process, is executed upon reception of a time signal indicating that the predetermined time has arrived (S502: NO), recording process is executed without executing process B (S503). The recording process of S503 is the same as S401 to S415 in the above-described embodiment.

[0076] In Modification 1, as in the above-described embodiment, the time signal indicating that it is the predetermined time corresponds to the "first signal" of the present invention. Also, in Modification 1, after process A including inspection process is executed upon reception of the time signal indicating that it is the predetermined time, the first received recording command corresponds to the "second signal" of the present invention.

[0077] In variant 1, suction purging is performed immediately before recording on the recording paper P, so that ink is not wasted even if there is a long period between receiving a time signal indicating that the specified time has arrived and receiving a recording command.

[0078] Furthermore, if the printer 1 is unplugged when the specified time arrives and power is being supplied from the battery 66 to the control device 80, the inspection process is executed but the inspection drive is not performed. Furthermore, if the battery 66 is out of power, the inspection process is not executed even when the specified time arrives, and naturally the inspection drive is not performed either.

[0079] Therefore, in this embodiment, when a print command is received, if the test drive has not been performed at the last specified time before the print command was received, the test drive is performed, thereby making it possible to identify abnormal nozzles.

[0080] In variant example 2, as shown in FIG. 10, the control device 80 has not received a power-on signal (S601: NO), the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 is the same as the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 when the test drive described below was last performed (S102: NO), and is in standby while not receiving a recording command (S501: NO).

[0081] Then, when a power-on signal is received (S601: YES), and when the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 becomes a temperature range different from the temperature range including the temperature indicated by the temperature signal received from the temperature sensor 67 when the test drive described below was last performed (S102: YES), the control device 80 executes process A (S104). On the other hand, when a recording command is received (S501: YES), the processes of S502, S105, and S503 are executed, as in the first modification.

[0082] In the second modification, even if there is a long period between the reception of the power-on signal and the reception of the recording command, ink is not wasted.

[0083] In Modification 2, the power-on signal corresponds to the "first signal" of the present invention. Also, in Modification 2, as in Modification 1, the first received recording command after process A including inspection process is executed upon reception of a time signal indicating that a predetermined time has arrived corresponds to the "second signal" of the present invention.

[0084] Furthermore, in Modifications 1 and 2, the control device 80 executes process A, including inspection process, in response to receiving a first signal (a time signal indicating that a predetermined time has arrived in Modification 1, and a power-on signal in Modification 2), and then executes process B when it receives the first recording command, but this is not limited to this. For example, the printer 1 may be capable of selectively recording in either low image quality or high image quality, and process A, including inspection process, may be executed in response to a first signal, and then process B may be executed when it receives the first recording command instructing it to record in high image quality.

[0085] In the above embodiment, process A is also executed when the temperature range including the temperature indicated by the temperature signal received from temperature sensor 67 becomes different from the temperature range including the temperature indicated by the temperature signal received from temperature sensor 67 when the last test drive was performed, but this is not limited to this. Process A may not be executed when the temperature range including the temperature indicated by the temperature signal received from temperature sensor 67 changes.

[0086] Furthermore, in the above-described embodiment, when recording on multiple sheets of recording paper P, the test drive is performed after recording on all of the recording paper P is completed and the number of sheets of recording paper P that have been recorded on since the last test drive was performed reaches a predetermined number (when C≧Ct), but this is not limited to this.

[0087] For example, when C≧Ct occurs during recording on a plurality of sheets of recording paper P, the recording may be interrupted and a test drive may be performed.

[0088] Alternatively, it is not necessary to perform test driving based on the number of sheets of recording paper P on which recording has been performed since the last test driving was performed.

[0089] Furthermore, in the above-described embodiment, when the determination signal output from the determination circuit 78 during the test drive performed at a predetermined time indicates the presence of an abnormal nozzle, flushing is performed as part of the recovery operation. Furthermore, when the power is subsequently turned on, suction purging is performed as the remaining part of the recovery operation, excluding the above-described part. However, this is not limited to this.

[0090] For example, the recovery operation may be a suction purge, and when the determination signal output from the determination circuit 78 during inspection driving, which is performed at a predetermined time, indicates the presence of an abnormal nozzle, part of the suction purge may be performed as part of the recovery operation.Furthermore, when the power is turned on thereafter, the remaining part of the suction purge may be performed as the part of the recovery operation excluding the part mentioned above.

[0091] Alternatively, the recovery operation may be flushing, and when the determination signal output from the determination circuit 78 during test driving, which is performed at a predetermined time, indicates the presence of an abnormal nozzle, part of the flushing may be performed as part of the recovery operation.Furthermore, when the power is turned on thereafter, the remaining part of the flushing may be performed as the part of the recovery operation excluding the part described above.

[0092] Furthermore, it is not limited to performing part of the recovery operation when the determination signal output from the determination circuit 78 during test drive performed at a predetermined time indicates the presence of an abnormal nozzle. For example, when the determination signal output from the determination circuit 78 during test drive performed at a predetermined time indicates the presence of an abnormal nozzle, part of the recovery operation may not be performed, and then when the power is turned on, all of the recovery operation may be performed.

[0093] Furthermore, in the above-described embodiment, information on the type of suction purge is stored in flash memory 84 and the type of suction purge is determined based on the determination signal output from determination circuit 78 during inspection driving, but this is not limiting. For example, if the determination signal output from determination circuit 78 during inspection driving indicates the presence of an abnormal nozzle, a uniform suction purge may be performed in the subsequent purge process.

[0094] In the above-described embodiment and modified example 1, if test driving is not performed when process A including test processing is executed in response to reception of a time signal indicating that a predetermined time has arrived, then test driving is executed in process B, which is executed when a power-on signal is received. In modified example 2, if test driving is not performed when process A including test processing is executed in response to reception of a power-on signal, then test driving is executed in process B, which is executed when a recording command is received. However, this is not limited to this.

[0095] If the inspection drive is not performed when the inspection process is executed in response to receiving a first signal (a time signal indicating that a predetermined time has arrived in the case of the above-described embodiment and modified example 1, or a power-on signal in the case of modified example 2), the inspection process does not have to be executed when the second signal (a power-on signal in the case of the above-described embodiment and modified example 1, or a recording command in the case of modified example 2) is subsequently received. In this case, since no flag information is stored in the flash memory 84 when the second signal is received, no recovery operation is performed.

[0096] 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.

[0097] Furthermore, the control device 80 stores information indicating the type of suction purge to be performed in the flash memory 84 as type information, but this is not limiting. For example, information that can determine the type of suction purge, such as the number of abnormal nozzles and the positions of the abnormal nozzles, may be stored as type information.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] Furthermore, in the above example, a nozzle 10 that does not eject ink is determined to be an abnormal nozzle, but this is not limited to this. For example, a signal output unit may be provided that outputs a signal depending on whether the ink ejection direction from the nozzle 10 is normal, and a nozzle 10 that has an abnormality in the ejection direction may be determined to be an abnormal nozzle based on the signal from this signal output unit.

[0103] Furthermore, in the above example, suction purging was performed in the purging process, but this is not limiting. For example, a pressure pump may be provided in the middle of 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 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 so-called pressure purging.

[0104] Furthermore, in the purging process, both suction by the suction pump 72 and pressurization by the pressure pump may be performed.

[0105] 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.

[0106] 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]

[0107] 1. Printer 4 Inkjet head 8 Maintenance Unit 10 nozzles 67 Temperature Sensor 68 Clock Section 72 Suction pump 78 Judgment circuit 80 Control device 84 Flash memory

Claims

1. a liquid ejection head having nozzles for ejecting liquid; a signal output unit that outputs a determination signal indicating whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid; a recovery means for performing a recovery operation to discharge liquid from the nozzle; A memory unit; a control device; The control device performing the test driving when a first signal different from an ejection instruction signal that instructs the liquid ejection head to eject liquid from the nozzles toward the ejection receiving medium is received; A liquid ejection device characterized in that, when a second signal, which is the ejection instruction signal, is received, the recovery means is caused to perform the recovery operation depending on the results of the test drive performed in response to receiving the first signal.

2. a clock unit that outputs a time signal indicating the time; 2. The liquid ejection device according to claim 1, wherein the first signal is a time signal indicating that a predetermined time has arrived.

3. 3. The liquid ejection device according to claim 1, wherein the first signal is a power-on signal indicating that the power supply has been turned on.

4. a liquid ejection head having nozzles for ejecting liquid; a signal output unit that outputs a determination signal indicating whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid; a recovery means for performing a recovery operation to discharge liquid from the nozzle; The clock section and A memory unit; a control device; The control device performing the test driving when the clock unit receives a first signal corresponding to the clocking of a predetermined time of day; A liquid ejection device characterized in that, when a second signal different from the first signal is received, the recovery means performs the recovery operation depending on the result of the test drive performed when the first signal is received.

5. 5. The liquid ejection apparatus according to claim 4, wherein the second signal is an ejection instruction signal that instructs the liquid ejection head to eject liquid from the nozzles toward an ejection receiving medium.

6. 6. The liquid ejection device according to claim 5, wherein the second signal is the ejection instruction signal that is received for the first time after receiving the first signal.

7. 5. The liquid ejection device according to claim 4, wherein the second signal is a power-on signal indicating that the power supply has been turned on.

8. The control device 5. The liquid ejection device according to claim 4, wherein when the power is turned on, if the test drive has not been performed at the last predetermined time before the power is turned on, the test drive is performed.

9. a liquid ejection head having nozzles for ejecting liquid; a signal output unit that outputs a determination signal indicating whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid; a recovery means for performing a recovery operation to discharge liquid from the nozzle; The clock section and A memory unit; a control device; The control device When the clock unit measures a predetermined time of day, the test drive is performed; A liquid ejection device characterized in that, when an ejection instruction signal is received instructing the liquid ejection head to eject liquid from the nozzle toward the ejection medium, the recovery means performs the recovery operation in accordance with the results of the inspection drive.

10. The control device The liquid ejection device according to claim 9, characterized in that, when the ejection instruction signal is received, if the test drive has not been performed at the last predetermined time before the ejection instruction signal is received, the test drive is performed.

11. The control device A liquid ejection device as described in any one of claims 1 to 10, characterized in that the inspection drive is performed again after the number of ejection media onto which liquid has been ejected by the liquid ejection head since the last inspection drive was performed has reached a predetermined number.

12. The control device A liquid ejection device as described in claim 11, characterized in that, while the liquid ejection head is ejecting liquid from the nozzles toward each of a plurality of ejection receiving media in sequence, if the number of ejection receiving media onto which liquid has been ejected by the liquid ejection head since the last time the inspection drive was performed reaches the predetermined number, the inspection drive is performed after the ejection of liquid onto the plurality of ejection receiving media is completed.

13. a temperature signal output unit that outputs a temperature signal indicating a temperature, The control device A liquid ejection device as described in any one of claims 1 to 12, characterized in that the inspection drive is performed when the temperature indicated by the temperature signal is within a first temperature range, and then the inspection drive is performed again when the temperature indicated by the temperature signal switches from a temperature within the first temperature range to a temperature within a second temperature range that is different from the first temperature range.

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