LIQUID EJECTION APPARATUS AND METHOD FOR MAINTENANCE OF LIQUID EJECTION HEAD IN LIQUID EJECTION APPARATUS

Abstract

To properly perform maintenance regardless of a liquid supplied to a liquid discharge head.SOLUTION: A first maintenance mode is set when prescribed conditions concerning an ink supplied to an ink jet head from an ink cartridge are satisfied, and a second maintenance mode is set when the prescribed conditions are not satisfied. Maintenance of the ink jet head is performed by performing suction purge at every time when a prescribed time has elapsed even when set to either the first or the second maintenance mode (S301, S302). Inspection processing is executed (S202) when set to the first maintenance mode when receiving an inspection indication signal (S201: YES), and suction purge is performed (S204) when there is an abnormal nozzle (S203: YES). Inspection processing and suction purge based on a result thereof are not performed when set to the second maintenance mode (S201: NO).SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection apparatus that ejects liquid from nozzles, and a maintenance method for a liquid ejection head in the liquid ejection apparatus. [Background technology]

[0002] As an example of a liquid ejection device that ejects droplets from nozzles, Patent Document 1 describes an inkjet recording device that performs recording by ejecting ink from nozzles. In the inkjet recording device described in Patent Document 1, a print head ejects ink supplied from an ink cartridge. Furthermore, in the inkjet recording device described in Patent Document 1, a nozzle is positioned between a light-emitting unit and a light-receiving unit, and the print head is driven while irradiating the light-receiving unit with laser light from the light-emitting unit. When ink is ejected, the laser light is blocked by the ink, but when ink is not ejected, the laser light is not blocked. Therefore, the amount of laser light received by the light-receiving unit changes depending on whether ink is ejected. Utilizing this, Patent Document 1 detects missing dots based on whether the amount of laser light received by the light-receiving unit is equal to or greater than a threshold. When a missing dot is detected, cleaning is performed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-300313 Summary of the Invention [Problem to be solved by the invention]

[0004] Ink cartridges not intended by the inkjet recording device manufacturer may be installed in the inkjet recording device of Patent Document 1. Ink cartridges not intended by the inkjet recording device manufacturer include, for example, ink cartridges manufactured by a manufacturer other than the inkjet recording device manufacturer, ink cartridges whose expiration date has passed, etc. In such ink cartridges, the ink properties may differ from those of ink cartridges intended by the inkjet recording device manufacturer.

[0005] On the other hand, in the inkjet recording device of Patent Document 1, the degree to which ejected ink blocks the laser light emitted from the light-emitting unit varies depending on the properties of the ink. Therefore, the amount of laser light received by the light-receiving unit when ink is ejected varies depending on the properties of the ink. Therefore, if an unexpected ink cartridge such as the one described above is installed, there is a risk that missing dots cannot be accurately detected when detecting missing dots based on whether the amount of laser light received by the light-receiving unit is equal to or greater than a threshold. If missing dots are incorrectly detected, unnecessary cleaning will be performed, resulting in wasted ink.

[0006] SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid ejection apparatus and a maintenance method for a liquid ejection head that are capable of performing appropriate maintenance regardless of the liquid supplied to the liquid ejection head. [Means for solving the problem]

[0007] The liquid ejection device of the present invention comprises: a liquid ejection head having a nozzle; a liquid tank connected to the liquid ejection head; a tank mounting portion to which the liquid tank is detachably mounted, and a connection flow path that connects the liquid ejection head and the liquid tank; a signal output unit that outputs a signal according to the state of liquid ejection from the nozzle when the liquid ejection head is driven for inspection to eject liquid from the nozzle, a discharge unit that performs a discharge operation to eject liquid from the nozzle, and a control unit; the liquid tank has an information storage unit that stores information about the liquid tank itself;the control unit selectively executes either a first maintenance process including a process of causing the discharge means to perform the discharge operation based on the signal output from the signal output unit, or a second maintenance process different from the first maintenance process, thereby performing maintenance on the liquid ejection head; a determination process for determining whether or not a predetermined condition related to the liquid supplied from the liquid tank to the liquid ejection head is satisfied based on the information stored in the information storage unit; When certain conditions are met, After the liquid tank is mounted on the tank mounting portion, the amount of liquid corresponding to the volume of the connecting flow path is discharged from the nozzle, and then A first maintenance mode is set in which maintenance of the liquid ejection head is performed by executing the first maintenance process, and when the predetermined condition is not satisfied, After the liquid tank is mounted on the tank mounting portion, the amount of liquid corresponding to the volume of the connecting flow path is discharged from the nozzle, and then By executing the second maintenance process, a second maintenance mode is set in which maintenance of the liquid ejection head is performed. A liquid ejection device of the present invention includes a liquid ejection head having nozzles, a liquid tank connected to the liquid ejection head, a signal output unit that outputs a signal according to the ejection state of liquid from the nozzles when the liquid ejection head is driven for testing to eject liquid from the nozzles, discharge means that performs a discharge operation to discharge liquid from the nozzles, and a control unit, wherein the control unit selectively executes either a first maintenance process that includes a process of causing the discharge means to perform the discharge operation based on the signal output from the signal output unit, or a second maintenance process that is different from the first maintenance process, thereby maintaining the maintenance of the liquid ejection head. When a predetermined condition related to the liquid supplied from the liquid tank to the liquid ejection head is satisfied, a first maintenance mode is set in which the first maintenance process is executed to perform maintenance on the liquid ejection head, and when the predetermined condition is not satisfied, a second maintenance mode is set in which the second maintenance process is executed to perform maintenance on the liquid ejection head, and in the second maintenance process, the liquid ejection head is not driven for inspection, and the ejection means is caused to perform the ejection operation based on whether or not a condition different from the condition related to the signal output from the signal output unit is satisfied. a signal output unit that outputs a signal corresponding to the state of liquid ejection from the nozzles when the liquid ejection head is driven for testing to eject liquid from the nozzles; discharge means that performs a discharge operation to discharge liquid from the nozzles; a memory unit; and a control unit, wherein the control unit performs maintenance of the liquid ejection head by selectively executing either a first maintenance process including a process of causing the discharge means to perform the discharge operation based on the signal output from the signal output unit, or a second maintenance process different from the first maintenance process, and when a predetermined condition related to the liquid supplied from the liquid tank to the liquid ejection head is satisfied, the control unit sets the liquid ejection head to a first maintenance mode in which maintenance of the liquid ejection head is performed by executing the first maintenance process, and when the predetermined condition is not satisfied, the control unit sets the liquid ejection head to a second maintenance mode in which maintenance of the liquid ejection head is performed by executing the second maintenance process; In the first maintenance process, the inspection drive is performed for each of the plurality of nozzles, and it is determined based on the signal output from the signal output unit whether or not the nozzle is an abnormal nozzle that is abnormal in ejecting liquid, and the number of abnormal nozzles is stored in the memory unit, and if an abnormal nozzle is present, the discharge means is caused to perform the discharge operation; in the second maintenance process, the inspection drive is performed for each of the plurality of nozzles, and it is determined based on the signal output from the signal output unit whether or not the nozzle is an abnormal nozzle, and if an abnormal nozzle is present and the number of abnormal nozzles is less than the number of abnormal nozzles stored in the memory unit plus a predetermined number, the discharge means is caused to perform the discharge operation; if an abnormal nozzle is present and the number of abnormal nozzles is equal to or greater than the number of abnormal nozzles stored in the memory unit plus the predetermined number, the discharge means is no longer caused to perform the discharge operation based on the signal output from the signal output unit, and the discharge means is caused to perform the discharge operation based on a condition different from the condition related to the signal output from the signal output unit. a signal output unit that outputs a signal according to a discharge state of liquid from the nozzles when the liquid discharge head is driven for testing to discharge liquid from the nozzles; discharge means that performs a discharge operation to discharge liquid from the nozzles; a memory unit; and a control unit, wherein the discharge means selectively performs, as the discharge operation, either a first discharge operation or a second discharge operation in which a larger amount of liquid is discharged than the first discharge operation; and the control unit selectively performs either a first maintenance process including a process of causing the discharge means to perform the discharge operation based on the signal output from the signal output unit, or a second maintenance process different from the first maintenance process, thereby performing maintenance of the liquid discharge head, and when a predetermined condition related to the liquid supplied from the liquid tank to the liquid discharge head is satisfied, a first maintenance mode in which maintenance of the liquid discharge head is performed by performing the first maintenance process. and when the predetermined condition is not satisfied, a second maintenance mode is set in which maintenance of the liquid ejection head is performed by executing the second maintenance process; in the first maintenance process, the inspection drive is performed for each of the plurality of nozzles, and it is determined whether or not the nozzle is an abnormal nozzle that is abnormal in ejecting liquid based on a signal output from the signal output unit, and the number of the abnormal nozzles is stored in the memory unit, and if an abnormal nozzle is present, the ejection means is caused to perform the first ejection operation; in the second maintenance process, the inspection drive is performed for each of the plurality of nozzles, and it is determined whether or not the nozzle is abnormal based on a signal output from the signal output unit, and if an abnormal nozzle is present and the difference between the number of the abnormal nozzles and the number of the abnormal nozzles stored in the memory unit is less than a threshold value, the ejection means is caused to perform the first ejection operation; and when the difference between the number of the abnormal nozzles and the number of the abnormal nozzles stored in the memory unit is equal to or greater than the threshold value, the ejection means is caused to perform the second ejection operation. Furthermore, a liquid ejection device of the present invention comprises a liquid ejection head having a nozzle, a liquid tank connected to the liquid ejection head, a signal output unit that outputs a signal according to the ejection state of liquid from the nozzle when the liquid ejection head is driven for testing to eject liquid from the nozzle, discharge means that performs a discharge operation to discharge liquid from the nozzle, and a control unit, wherein the signal output unit comprises an electrode and voltage application means that applies a voltage to the electrode, and outputs a signal according to an electrical change in the electrode when the test driving is performed with a voltage applied to the electrode by the voltage application means, and the control unit performs a test based on the signal output from the signal output unit. and a second maintenance process different from the first maintenance process, whereby maintenance of the liquid ejection head is performed by selectively executing either a first maintenance process including a process of causing the ejection means to perform the ejection operation by using the liquid tank, or a second maintenance process different from the first maintenance process. When a predetermined condition regarding the liquid supplied from the liquid tank to the liquid ejection head is satisfied, a first maintenance mode is set in which maintenance of the liquid ejection head is performed by executing the first maintenance process, and when the predetermined condition is not satisfied, a second maintenance mode is set in which maintenance of the liquid ejection head is performed by executing the second maintenance process. a control unit that controls the signal output unit to output a signal in accordance with the amount of light received by the light-receiving unit when an operation for ejecting liquid from the nozzle toward a position between the light-emitting unit and the light-receiving unit is performed as the inspection drive; and a second maintenance process different from the first maintenance process, thereby performing maintenance on the liquid ejection head. When a predetermined condition regarding the liquid supplied from the liquid tank to the liquid ejection head is satisfied, the liquid ejection head is set to a first maintenance mode in which maintenance of the liquid ejection head is performed by executing the first maintenance process, and when the predetermined condition is not satisfied, the liquid ejection head is set to a second maintenance mode in which maintenance of the liquid ejection head is performed by executing the second maintenance process.

[0008] A maintenance method for a liquid ejection head in a liquid ejection device of the present invention is a maintenance method for a liquid ejection head in a liquid ejection device comprising: a liquid ejection head having a nozzle; a liquid tank connected to the liquid ejection head; a tank mounting part to which the liquid tank is detachably mounted; a connection flow path connecting the liquid ejection head and the liquid tank; a signal output part that outputs a signal according to the ejection state of liquid from the nozzle when the liquid ejection head is driven for inspection to eject liquid from the nozzle; and an ejection means that performs an ejection operation to eject liquid from the nozzle, wherein the liquid tank has an information storage part that stores information about itself, and the method comprises the steps of: It is determined whether or not a predetermined condition regarding the liquid supplied from the liquid tank to the liquid ejection head is met, and if the predetermined condition is met, after the liquid tank is attached to the tank attachment section, a quantity of liquid corresponding to the volume of the connecting flow path is discharged from the nozzle, and then maintenance of the liquid ejection head is performed by a first maintenance operation including the discharge operation by the discharge means based on the signal output from the signal output section; if the predetermined condition is not met, after the liquid tank is attached to the tank attachment section, a quantity of liquid corresponding to the volume of the connecting flow path is discharged from the nozzle, and then maintenance of the liquid ejection head is performed by a second maintenance operation different from the first maintenance operation. Furthermore, a maintenance method for a liquid ejection head in a liquid ejection device of the present invention is a maintenance method for a liquid ejection head in a liquid ejection device comprising a liquid ejection head having a nozzle, a liquid tank connected to the liquid ejection head, a signal output unit that outputs a signal corresponding to the ejection state of liquid from the nozzle when the liquid ejection head is driven for inspection to eject liquid from the nozzle, and an ejection means that performs an ejection operation to eject liquid from the nozzle, wherein when a predetermined condition regarding the liquid supplied from the liquid tank to the liquid ejection head is satisfied, maintenance of the liquid ejection head is performed by a first maintenance operation including the ejection operation by the ejection means based on a signal output from the signal output unit, and when the predetermined condition is not satisfied, maintenance of the liquid ejection head is performed by a second maintenance operation different from the first maintenance operation, and in the second maintenance operation, the inspection drive is not performed on the liquid ejection head, and the ejection operation by the ejection means is performed based on whether a condition different from the condition regarding the signal output from the signal output unit is satisfied. Furthermore, a maintenance method for a liquid ejection head in a liquid ejection device of the present invention is a maintenance method for a liquid ejection head in a liquid ejection device comprising: a liquid ejection head having a plurality of nozzles; a liquid tank connected to the liquid ejection head; a signal output unit that outputs a signal according to the ejection state of liquid from the nozzles when the liquid ejection head is driven for testing to eject liquid from the nozzles; discharge means that performs a discharge operation to discharge liquid from the nozzles; and a memory unit, wherein when a predetermined condition related to the liquid supplied from the liquid tank to the liquid ejection head is satisfied, maintenance of the liquid ejection head is performed by a first maintenance operation including the discharge operation by the discharge means based on a signal output from the signal output unit; and when the predetermined condition is not satisfied, maintenance of the liquid ejection head is performed by a second maintenance operation different from the first maintenance operation, and the test driving is performed for each of the plurality of nozzles in the first maintenance operation. Based on the signal output from the signal output unit, it is determined whether the nozzle is an abnormal nozzle that is abnormal in ejecting liquid, and the number of abnormal nozzles is stored in the memory unit, and if an abnormal nozzle is present, the discharge operation is performed by the discharge means, and in the second maintenance operation, the inspection drive is performed for each of the plurality of nozzles, and based on the signal output from the signal output unit, it is determined whether the nozzle is an abnormal nozzle, and if an abnormal nozzle is present and the number of abnormal nozzles is less than the number of abnormal nozzles stored in the memory unit plus a predetermined number, the discharge operation is performed by the discharge means, and if an abnormal nozzle is present and the number of abnormal nozzles is equal to or greater than the number of abnormal nozzles stored in the memory unit plus the predetermined number, from this point onwards, the discharge operation by the discharge means is not performed based on the signal output from the signal output unit, and the discharge operation by the discharge means is performed based on conditions different from the conditions related to the signal output from the signal output unit. A maintenance method for a liquid ejection head in a liquid ejection device of the present invention includes a liquid ejection head having a plurality of nozzles, a liquid tank connected to the liquid ejection head, a signal output unit that outputs a signal according to the ejection state of liquid from the nozzles when the liquid ejection head is driven for inspection to eject liquid from the nozzles, and an ejection unit that performs an ejection operation to eject liquid from the nozzles. A memory unit; a discharge means for selectively performing, as the discharge operation, either a first discharge operation or a second discharge operation in which a larger amount of liquid is discharged than in the first discharge operation, and when a predetermined condition related to the liquid supplied from the liquid tank to the liquid discharge head is satisfied, maintenance of the liquid discharge head is performed by a first maintenance operation including the discharge operation by the discharge means based on a signal output from the signal output unit, and when the predetermined condition is not satisfied, maintenance of the liquid discharge head is performed by a second maintenance operation different from the first maintenance operation, and in the first maintenance operation, the inspection driving is performed for each of the plurality of nozzles, and a signal output from the signal output unit is and, based on the signal output from the signal output unit, determines whether the nozzle is an abnormal nozzle having an abnormality in the discharge of liquid, and stores the number of abnormal nozzles in the memory unit. If an abnormal nozzle is present, the first discharge operation is performed by the discharge means. In the second maintenance operation, the inspection drive is performed for each of the plurality of nozzles, and, based on the signal output from the signal output unit, determines whether the nozzle is abnormal. If an abnormal nozzle is present and the difference between the number of abnormal nozzles and the number of abnormal nozzles stored in the memory unit is less than a threshold value, the first discharge operation is performed by the discharge means. If the difference between the number of abnormal nozzles and the number of abnormal nozzles stored in the memory unit is equal to or greater than the threshold value, the second discharge operation is performed by the discharge means. [Effects of the Invention]

[0009] In the present invention, when a predetermined condition related to the liquid supplied from the liquid tank to the liquid ejection head is satisfied, a first maintenance mode is set in which a first maintenance process is carried out to perform maintenance on the liquid ejection head, including a process of causing the ejection means to eject the liquid based on a signal output from the signal output unit, thereby enabling the malfunctioning nozzle to be restored.

[0010] On the other hand, when the above-mentioned predetermined conditions are not met, the signal output from the signal output unit may not accurately indicate whether the nozzle is an abnormal nozzle that is experiencing an abnormality in liquid ejection. Therefore, in the present invention, when the above-mentioned predetermined conditions are not met, a second maintenance mode is set in which maintenance of the liquid ejection head is performed by a second maintenance process that is different from the first maintenance process. [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] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] 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 4] FIG. 10A is a diagram showing the change in voltage of the detection electrode when ink is ejected from the nozzle, and FIG. 10B is a diagram showing the change in voltage of the detection electrode when ink is not ejected from the nozzle. [Figure 5] FIG. 2 is a block diagram showing the electrical configuration of the printer. [Figure 6] 10 is a flowchart showing the flow of processing by the control unit when an ink cartridge is mounted in the cartridge mounting unit. [Figure 7] 10A is a flowchart showing the flow of processing by the control unit when an inspection instruction signal is received, and FIG. 10B is a flowchart showing the flow of processing performed by the control unit while power is being supplied to the printer. [Figure 8]10 is a flowchart showing the flow of processing by a control unit when an inspection instruction signal is received in Modification 1. [Figure 9] 10 is a flowchart showing the flow of processing by the control unit when an examination instruction signal is received in Modification 2. [Figure 10] FIG. 11 is a schematic diagram illustrating the configuration of a printer according to a third modification. [Figure 11] FIG. 4 is a view of the ejection detection device as seen from the downstream side in the transport direction. 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 "discharge 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. 5) 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. The cartridge holder 13 has four cartridge mounting sections 41 ("tank mounting sections" of the present invention) lined up in the scanning direction. An ink cartridge 14 ("liquid tank" of the present invention) is removably mounted in each cartridge mounting section 41. The ink cartridges 14 store black, yellow, cyan, and magenta ink ("liquid" of the present invention) in order from the one mounted in the cartridge mounting section 41 on the right side in the scanning direction.

[0016] 2, the cartridge holder 13 has supply flow paths 42 connected to each cartridge mounting portion 41. The four supply flow paths 42 corresponding to the four cartridge mounting portions 41 are connected to the subtank 3 via four tubes 15.

[0017] Meanwhile, an ink storage chamber 51 for storing ink is formed inside the ink cartridge 14. When the ink cartridge 14 is installed in the cartridge mounting portion 41, it is located at the lower end of the upstream end in the transport direction and has an ink supply portion 52 connected to the ink storage chamber 51. The ink supply portion 52 is provided with a valve (not shown). When the ink cartridge 14 is not installed in the cartridge mounting portion 41, the valve is closed, preventing ink from leaking from the ink storage chamber 51 through the ink supply portion 52. When the ink cartridge 14 is installed in the cartridge mounting portion 41, the ink supply portion 52 is connected to the supply flow path 42. At this time, the valve is opened, and the ink stored in the ink storage chamber 51 flows into the supply flow path 42 via the ink supply portion 52. As a result, the four colors of ink stored in the four ink cartridges 14 are supplied to the subtank 3 via the four tubes 15.

[0018] Furthermore, a substrate 53 (the "information storage unit" of the present invention) is attached to the surface 14a of the ink cartridge 14, which becomes the upper surface when the ink cartridge 14 is attached to the cartridge mounting portion 41. Information about the ink cartridge 14 is stored on the substrate 53. In this embodiment, the information about the ink cartridge 14 includes information for authenticating the ink cartridge 14 and information about the manufacturing date of the ink cartridge 14. Correspondingly, a contact portion 43 is provided on the ceiling surface 41a of the cartridge mounting portion 41. The contact portion 43 is connected to a control unit 80, which will be described later. When the ink cartridge 14 is attached to the cartridge mounting portion 41, the substrate 53 is connected to the contact portion 43. This allows the information about the ink cartridge 14 stored on the substrate 53 to be sent to the control unit 80.

[0019] The inkjet head 4 is mounted on the carriage 2 and connected to the lower end of the subtank 3. The four colors of ink are supplied to the inkjet head 4 from the subtank 3. In this embodiment, the supply flow path 42, the tube 15, and the flow path inside the subtank 3 correspond to the "connection flow path" of the present invention that connects the ink cartridge 14 and the inkjet head 4.

[0020] The inkjet head 4 ejects ink from a plurality of nozzles 10 formed on its lower surface, a nozzle surface 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 surface 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 nozzle row 9 on the right side in the scanning direction.

[0021] 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. 5) 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.

[0022] 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.

[0023] The cap 71 can be raised and lowered by a cap lifting mechanism 88 (see FIG. 5). 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 (not shown) or the like that is arranged around the nozzle surface 4a of the inkjet head 4.

[0024] 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.

[0025] 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.

[0026] As shown in FIG. 3, 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 voltage (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 voltage of the signal output from the detection electrode 76 with a threshold value Vt and outputs a signal according to the result.

[0027] 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. 4(a), the charged ink approaches the detection electrode 76, and until the ink lands on the detection electrode 76, the voltage of the detection electrode 76 decreases from the voltage Va when the inkjet head 4 is not driven and reaches a voltage Vb lower than the voltage Va. Then, after the charged ink lands on the detection electrode 76, the voltage of the detection electrode 76 gradually rises and returns to the voltage Va. That is, during the driving period Td of the inkjet head 4, the voltage of the detection electrode 76 changes.

[0028] On the other hand, when no ink is ejected from the nozzle 10, as shown in Fig. 4(b), during the driving period Td of the inkjet head 4, the voltage of the detection electrode 76 hardly changes from the voltage Va. Therefore, a threshold value Vt (Vb < Vt < Va) is set in the determination circuit 78 to distinguish between these. Then, the determination circuit 78 outputs a signal according to whether the minimum voltage of the voltage signal output from the detection electrode 76 during the driving period Td of the inkjet head 4 is lower than the threshold value Vt. 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 signal according to the ejection state of the ink from the nozzle 10.

[0029] Furthermore, although a positive voltage is applied to the detection electrode 76 by the high-voltage power supply circuit 77 here, a negative voltage (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, contrary 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 voltage of the detection electrode 76 rises from voltage Va until the ink lands on the detection electrode 76. After the ink lands on the detection electrode 76, the voltage of the detection electrode 76 gradually decreases and returns to voltage Va.

[0030] <Printer electrical configuration> Next, the electrical configuration of the printer 1 will be described. As shown in Figure 5, the printer 1 is equipped with a control unit 80. The control unit 80 is made up of a CPU (Central Processing Unit) 81, a ROM (Read Only Memory) 82, a RAM (Random Access Memory) 83, a flash memory 84, an ASIC (Application Specific Integrated Circuit) 85, and the like. The control unit 80 controls the operation 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, and the like. The control unit 80 also receives information about the ink cartridges 14 from the circuit board 53, and receives a signal from the determination circuit 78 corresponding to the state of ink ejection from the nozzles 10 during inspection drive.

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

[0032] <Processing for setting maintenance mode> Next, the process performed by the control unit 80 to set the maintenance mode in this embodiment will be described. In this embodiment, the maintenance mode for performing maintenance on the inkjet head 4 in the printer 1 can be selectively set to either a first maintenance mode or a second maintenance mode. The control unit 80 switches between the first maintenance mode and the second maintenance mode by performing processing in accordance with the flow in FIG. 6. The flow in FIG. 6 is started, for example, when the ink cartridge 14 is first installed in the cartridge installation unit 41 in the printer 1. Note that the operation for maintaining the inkjet head 4 when the first maintenance mode and the second maintenance mode are set will be described later.

[0033] 6 in more detail, the control unit 80 first executes authentication processing (S101). In the authentication processing, the control unit 80 determines whether the ink cartridge 14 is an authenticated ink cartridge based on authentication information received from the circuit board 53 of the ink cartridge 14 installed in the cartridge installation unit 41. For example, if the authentication information indicates that the ink cartridge is designated by the manufacturer of the printer 1, the control unit 80 determines that the ink cartridge is an authenticated ink cartridge. If the authentication information indicates that the ink cartridge is not the designated ink cartridge, the control unit 80 determines that the ink cartridge is not an authenticated ink cartridge.

[0034] Next, the control unit 80 waits until a predetermined amount of ink stored in the ink cartridge 14 attached to the cartridge mounting unit 41 is discharged by recording on the recording paper P, suction purging, or the like (S102: NO). Here, the predetermined amount refers to an amount corresponding to the volume of the supply flow path 42, the tube 15, and the flow path within the subtank 3, i.e., the volume of the flow path connecting the cartridge mounting unit 41 and the inkjet head 4. In addition, in S102, the above determination is made by estimating the amount of ink discharged based on, for example, the number of times ink is ejected from the nozzle 10 after the ink cartridge 14 is attached to the cartridge mounting unit 41, the number of times suction purging has been performed, and the like.

[0035] When the predetermined amount of ink has been discharged (S102: YES), the control unit 80 sets the ink cartridges 14 of all colors to the first maintenance mode (S105) if the ink cartridges 14 are all certified ink cartridges (S103: YES) and are within a predetermined period of time (e.g., within one year) from the date of manufacture of the ink cartridges 14 (S104: YES). Setting the ink cartridges 14 to the first maintenance mode means, for example, storing information in the flash memory 84 indicating that maintenance of the inkjet heads 4 will be performed in the first maintenance mode. As a result, if the ink cartridges 14 are currently set to the first maintenance mode, the first maintenance mode is maintained, and if the ink cartridges 14 are currently set to the second maintenance mode, the mode is switched from the second maintenance mode to the first maintenance mode. In this embodiment, the conditions that the ink cartridges 14 are certified ink cartridges and are within a predetermined period of time from the date of manufacture of the ink cartridges 14 correspond to the "predetermined condition" of the present invention.

[0036] On the other hand, if any of the ink cartridges 14 are not authenticated ink cartridges (S103: NO), or if any of the ink cartridges 14 have been manufactured for a predetermined period of time (S104: NO), the control unit 80 sets the ink cartridges 14 to the second maintenance mode (S106). Here, setting the ink cartridges 14 to the second maintenance mode means, for example, storing information in the flash memory 84 indicating that maintenance of the inkjet heads 4 will be performed in the second maintenance mode. As a result, if the ink cartridges 14 are currently set to the first maintenance mode, the mode is switched from the first maintenance mode to the second maintenance mode, and if the ink cartridges 14 are currently set to the second maintenance mode, the state in which the ink cartridges 14 are set to the second maintenance mode is maintained.

[0037] After setting the first maintenance mode in S105, the control unit 80 waits and maintains the state set to the first maintenance mode as long as none of the ink cartridges 14 installed in any of the cartridge installation units 41 have been replaced (S107: NO) and a predetermined period has not elapsed since the date of manufacture for all of the ink cartridges 14 (S108: NO).

[0038] If the ink cartridge 14 installed in any of the cartridge mounting sections 41 has been replaced (S107: YES), the process returns to S101. If a predetermined period of time has passed since the manufacturing date for any of the ink cartridges 14 (S108: YES), the process proceeds to S106 and the second maintenance mode is set.

[0039] After setting the second maintenance mode in S106, the control unit 80 waits as long as none of the ink cartridges 14 installed in any of the cartridge mounting units 41 have been replaced (S109: NO), and the state set to the second maintenance mode is maintained. Then, when an ink cartridge 14 installed in any of the cartridge mounting units 41 has been replaced (S109: YES), the process returns to S101.

[0040] <Processing when receiving an inspection instruction signal> Next, the flow of processing by the control unit 80 when an inspection instruction signal is received instructing that the nozzle 10 be inspected to determine whether it is an abnormal nozzle will be described. When an inspection instruction signal is received, the control unit 80 performs processing in accordance with the flow shown in FIG. 7(a). For example, if the printer 1 has a clock unit (not shown) and is set to inspect whether it is an abnormal nozzle at each predetermined time, the control unit 80 receives the inspection instruction signal from the clock unit when the predetermined time arrives. Alternatively, for example, the control unit 80 receives the inspection instruction signal when a user operates an operation unit (not shown) of the printer 1 or a PC (not shown) connected to the printer 1 to input the inspection instruction signal.

[0041] 7(a), if the first maintenance mode is selected (S201: YES), the control unit 80 executes an inspection process (S202). In the inspection process, the control unit 80 sequentially drives each of the nozzles 10 of the inkjet head 4 to perform an inspection drive to eject ink from the nozzle 10. Then, based on a signal output from the determination circuit 78 at this time, the control unit 80 stores information in the flash memory 84 as to whether or not the nozzle 10 is an abnormal nozzle.

[0042] Next, based on the information stored in the flash memory 84 during the inspection process, it is determined whether or not there is an abnormal nozzle among the multiple nozzles 10 of the inkjet head 4 (S203). If there is no abnormal nozzle (S203: NO), the process ends as is. If there is an abnormal nozzle (S203: YES), the control unit 80 performs a purge process (S204) and then performs the process. In the purge process, the control unit 80 controls a suction pump or the like to perform a suction purge.

[0043] On the other hand, if the printer is not set to the first maintenance mode, i.e., if the printer is set to the second maintenance mode (S201: NO), no further processing is performed and the process ends. At this time, a notification signal may be output to notify the user that an inspection to determine whether or not there is an abnormal nozzle will not be performed, and then the process ends. The notification signal is, for example, a signal for displaying a message on a display unit (not shown) of the printer 1 or on a PC (not shown) connected to the printer 1.

[0044] <Processing for periodic purging> Next, the process by the control unit 80 for periodically performing suction purging will be described. In the printer 1, the control unit 80 performs the process according to the flow in Fig. 7(b), thereby periodically performing suction purging. The flow in Fig. 7(b) starts when power supply to the printer 1 is started, for example, when the printer 1 is plugged in, and continues while power is being supplied to the printer 1.

[0045] 7(b) in detail, if a predetermined time has not elapsed since the previous suction purge, the process waits (S301: NO), but if a predetermined time has elapsed since the previous suction purge (S301: YES), the process executes purging (S302), and returns to S301. In the purge process of S302, the control unit 80 also controls the suction pump 72 and the like to perform suction purge. As a result, in this embodiment, suction purge is performed every time a predetermined time has elapsed.

[0046] In this embodiment, when the control unit 80 performs processing in accordance with the flow of Figures 7(a) and (b), and is set to the first maintenance mode, maintenance of the inkjet head 4 is performed by performing a suction purge when an abnormal nozzle is present and when a predetermined time has passed since the previous suction purge.

[0047] On the other hand, when the second maintenance mode is set, the inspection process and the suction purge based on the results of the inspection process are not performed, and maintenance of the inkjet head 4 is performed by performing the suction purge when a predetermined time has elapsed since the previous suction purge.

[0048] In this embodiment, the processes of S202 to S204 correspond to "processing for causing the discharge means to perform a discharge operation based on a signal output from the signal output unit" of the present invention, and this process combined with the processes of S301 and S302 corresponds to "first maintenance process" of the present invention. Also, in this embodiment, the processes of S301 and S302 correspond to "second maintenance process" of the present invention. Also, in this embodiment, the condition that a predetermined time has elapsed since the previous suction purge corresponds to "a condition different from the condition related to the signal output from the signal output unit" of the present invention.

[0049] <Effects> The properties of the ink in the ink cartridge 14 may differ depending on whether the ink cartridge is specified by the printer 1 manufacturer or not. Furthermore, the properties of the ink in the ink cartridge 14 may change over time. That is, the properties of the ink supplied from the ink cartridge 14 to the inkjet head 4 may differ depending on whether the above-mentioned predetermined conditions are met. On the other hand, if the ink supplied from the ink cartridge 14 to the inkjet head 4 is not the expected ink, the way in which the voltage at the detection electrode 76 changes when the test drive is performed may change, and the signal output from the determination circuit 78 may not accurately indicate whether the nozzle is abnormal.

[0050] Therefore, in this embodiment, when the above-mentioned predetermined conditions are met, it is determined whether or not there is an abnormal nozzle based on the signal output from the determination circuit 78, and if there is an abnormal nozzle, the system is set to a first maintenance mode in which a first maintenance process including a purging process is performed to perform maintenance on the inkjet head. This makes it possible to restore the abnormal nozzle. Note that when the above-mentioned predetermined conditions are met, maintenance of the inkjet head 4 is also performed by performing a purging process every time a predetermined period of time has elapsed.

[0051] On the other hand, when the above-mentioned predetermined conditions are not met, the purge process based on the result of the inspection process (the signal output from the determination circuit 78) is not executed, and the second maintenance mode is set in which the purge process is executed every time a predetermined period of time elapses to perform maintenance on the inkjet head 4. This makes it possible to prevent unnecessary suction purges from being executed based on erroneous determination results as to whether or not a nozzle is abnormal.

[0052] That is, in this embodiment, by switching between the first maintenance mode and the second maintenance mode based on whether or not the above-mentioned specified conditions are met, maintenance of the inkjet head 4 can be performed appropriately according to the ink supplied from the ink cartridge 14 to the inkjet head 4.

[0053] In this embodiment, the ink cartridge 14 is removably mounted in the cartridge mounting portion 41, and the ink cartridge 14 has a substrate 53 that stores information about the ink cartridge 14. Based on the information about the ink cartridge 14 stored on the substrate 53, it can be determined whether the above-mentioned predetermined conditions are met.

[0054] Furthermore, in this embodiment, when the ink cartridge 14 is mounted in the cartridge mounting portion 41, the ink in the ink cartridge 14 is not immediately supplied to the inkjet head 4. Rather, the ink in the flow path (supply flow path 42, tube 15, subtank 3, etc.) between the cartridge mounting portion 41 and the inkjet head 4 is supplied to the inkjet head 4, and then the ink in the ink cartridge 14 begins to be supplied to the inkjet head 4.

[0055] Therefore, in this embodiment, if the above-mentioned predetermined conditions are met, after the ink cartridge 14 is mounted in the cartridge mounting portion 41, the first maintenance mode is set after an amount of ink corresponding to the volume of the flow path between the cartridge mounting portion 41 and the inkjet head 4 has been discharged. On the other hand, if the above-mentioned predetermined conditions are not met, after the ink cartridge 14 is mounted in the cartridge mounting portion 41, the second maintenance mode is set after an amount of ink corresponding to the volume of the flow path between the cartridge mounting portion 41 and the inkjet head 4 has been discharged. In this way, after the ink in the ink cartridge 14 starts to be supplied to the inkjet head 4, the first or second maintenance mode can be set depending on whether the above-mentioned predetermined conditions are met.

[0056] Furthermore, in this embodiment, whether or not a nozzle is abnormal is determined based on a signal output from the determination circuit 78 in response to a change in voltage at the detection electrode 76 when a test drive is performed to eject ink from the nozzle 10 toward the detection electrode 76. Meanwhile, the change in voltage at the detection electrode 76 when ink is ejected toward the detection electrode 76 varies depending on the properties of the ink ejected from the nozzle 10. Therefore, in a printer 1 that determines whether or not a nozzle is abnormal in the manner described above, it is very significant to set the printer 1 to the first maintenance mode when the above-mentioned predetermined conditions are met, and to the second maintenance mode when the above-mentioned predetermined conditions are not met.

[0057] <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.

[0058] The operation for maintenance of the inkjet head 4 when the second maintenance mode is set is not limited to that in the above-described embodiment.

[0059] In Modification 1, when the control unit 80 receives an inspection command signal, it performs processing according to the flow of FIG. 8. More specifically, when the control unit 80 receives the inspection command signal and the first maintenance mode is selected (S401: YES), the control unit 80 executes the same inspection processing as S202 (S402). If no abnormal nozzles are present (S403: NO), the control unit 80 terminates the processing. If an abnormal nozzle is present (S403: YES), the control unit 80 stores the number of abnormal nozzles, obtained from the information on whether or not a nozzle is abnormal, stored in the flash memory 84 by the inspection processing, as Kt in the flash memory 84 (S404). If the flash memory 84 stores information on the number of abnormal nozzles Kt based on the results of a previous inspection processing, the information on the number of abnormal nozzles Kt stored in the flash memory 84 is updated in S404. The control unit 80 then executes a purge processing (S405) and terminates the processing.

[0060] On the other hand, if the second maintenance mode is set (S401: NO), the control unit 80 then determines whether or not an inspection stop flag indicating that inspection processing should be stopped is stored in the flash memory 84 (S406). If an inspection stop flag is stored in the flash memory 84 (S406: YES), the process ends.

[0061] If the inspection stop flag is not stored in the flash memory 84 (S406: NO), the control unit 80 executes the inspection process (S407). If there are no abnormal nozzles (S408: NO), the process ends. If there are abnormal nozzles (S408: YES), the control unit 80 determines whether the number K of abnormal nozzles obtained from the results of the inspection process is less than [Kt+Ks], which is Kt plus a predetermined number Ks (S409).

[0062] If the number K of abnormal nozzles is less than [Kt+Ks] (S409: YES), the control unit 80 executes the processes of S404 and S405. However, in this case, in S404, the number of abnormal nozzles obtained from the results of the inspection process of S407 is stored as Kt in the flash memory 84. If the number K of abnormal nozzles is equal to or greater than [Kt+Ks] (S409: NO), the control unit 80 stores an inspection stop flag in the flash memory 84 (S410) and ends the process.

[0063] As a result, in variant 1, when the first maintenance mode is set, suction purging is performed to perform maintenance on the inkjet head 4, similar to the above-described embodiment, when an abnormal nozzle is present and when a predetermined time has elapsed since the previous suction purging.

[0064] Furthermore, in variant 1, when the second maintenance mode is set and the number K of abnormal nozzles is less than [Kt+Ks], suction purging is performed to perform maintenance on the inkjet head 4 when an abnormal nozzle is present and when a predetermined time has elapsed since the previous suction purging, just as when the first maintenance mode is set.

[0065] On the other hand, in variant 1, when the second maintenance mode is set and the number K of abnormal nozzles is equal to or greater than [Kt+Ks], the inspection process and suction purge based on the results of the inspection process are not performed, and when a predetermined time has passed since the previous suction purge, suction purge is performed to perform maintenance on the inkjet head 4.

[0066] As mentioned above, if the above predetermined conditions are not met, the signal output from the determination circuit 78 when the test drive is performed may not accurately indicate whether or not the nozzle is abnormal. If a nozzle 10 that is not abnormal is mistakenly determined to be abnormal, an unnecessary suction purge will be performed, causing ink to be discharged unnecessarily.

[0067] Therefore, in Modification 1, when inspection driving is performed while the device is set to the first maintenance mode, the number Kt of abnormal nozzles is stored. Then, when inspection driving is performed while the device is set to the second maintenance mode, if the number K of abnormal nozzles is less than [Kt+Ks], which is the stored number Kt of abnormal nozzles plus a predetermined number Ks, it is highly likely that an accurate determination has been made as to whether or not a nozzle is abnormal, and so suction purging is performed based on a signal from the determination circuit 78. As a result, even when the device is set to the second maintenance mode, if an accurate determination has been made as to whether or not a nozzle is abnormal, suction purging can be performed appropriately based on the signal from the determination circuit 78, and the abnormal nozzle can be restored.

[0068] On the other hand, when test driving is performed while the second maintenance mode is set, if the number K of abnormal nozzles is equal to or greater than [Kt+Ks], which is the stored number Kt of abnormal nozzles plus a predetermined number Ks, there is a high possibility that a nozzle 10 that is not an abnormal nozzle has been mistakenly determined to be an abnormal nozzle, so from this point on, suction purge based on the test processing results (signal from the judgment circuit 78) is not performed, and instead, when a predetermined period has passed since the previous suction purge (based on conditions different from the conditions related to the signal from the judgment circuit 78), it is possible to prevent unnecessary suction purges and wasted ink due to test driving that cannot accurately determine whether a nozzle is abnormal.

[0069] In the second modification, the maintenance unit 8 can selectively perform either a standard purge (the "first discharge operation" of the present invention) or a strong purge (the "second discharge operation" of the present invention) as a suction purge. A strong purge discharges more ink than a standard purge. For example, a strong purge requires a longer drive time of the suction pump 72 than a standard purge. Alternatively, for example, a strong purge requires a faster rotation speed of the suction pump 72 than a standard purge. Alternatively, for example, a strong purge requires a longer drive time of the suction pump 72 and a faster rotation speed of the suction pump 72 than a standard purge.

[0070] In Modification 2, when the control unit 80 receives an inspection instruction signal, it performs processing in accordance with the flow of Fig. 9. Explaining in more detail, when the control unit 80 receives an inspection instruction signal, it executes the inspection process (S501). Then, if there are no abnormal nozzles (S502: NO), it ends the process.

[0071] If abnormal nozzles are present (S502: YES) and the first maintenance mode is set (S503: YES), the control unit 80 stores the number of abnormal nozzles as Kt in the flash memory 84 (S504), performs a normal purge process (S505), and then ends the process. In the normal purge process, the control unit 80 controls the suction pump 72 and the like to perform a normal purge.

[0072] If abnormal nozzles are present (S502: YES) and the second maintenance mode is set (S503: NO), the control unit 80 determines whether the absolute value |K - Kt| of the difference between the number K of abnormal nozzles and Kt stored in the flash memory 84 is less than the threshold value Kr (S506). If the absolute value |K - Kt| is less than the threshold value Kr (S506: YES), the control unit 80 executes the processes of S504 and S505. If the absolute value |K - Kt| is equal to or greater than the threshold value Kr (S506: NO), the control unit 80 executes a strong purge process (S507) and then terminates the process. In the strong purge process, the control unit 80 controls the suction pump 72 and the like to perform a strong purge.

[0073] As a result, in the second modification, when the first maintenance mode is set and an abnormal nozzle is present, maintenance of the inkjet head 4 is performed by carrying out a normal purge.

[0074] In addition, in variant 2, the second maintenance mode is set, and when an abnormal nozzle is present, if the absolute value |K-Kt| is less than the threshold value Kr, a normal purge is performed to maintain the inkjet head 4, and if the absolute value |K-Kt| is greater than or equal to the threshold value Kr, a strong purge is performed to maintain the inkjet head 4.

[0075] As mentioned above, if the above-mentioned predetermined conditions are not met, the signal output from the determination circuit 78 when the test drive is performed may not accurately indicate whether or not there is an abnormal nozzle. In this case, the properties of the ink will be significantly different from when the above-mentioned predetermined conditions are met, and if there is an abnormal nozzle, there is a risk that the abnormal nozzle will not be able to be restored even if a normal purge similar to that performed when the first maintenance mode is set is performed.

[0076] Therefore, in Modification 2, when inspection driving is performed while the printer is set to the first maintenance mode, the number Kt of abnormal nozzles is stored. Then, when inspection driving is performed while the printer is set to the second maintenance mode, if the absolute value |K-Kt| of the difference between the number K of abnormal nozzles and the stored number Kt of abnormal nozzles is less than the threshold value Kr, it is determined accurately whether or not a nozzle is abnormal, and there is a high possibility that the ink properties are not significantly different from when the printer is set to the first maintenance mode, so a normal purge is performed based on a signal from the determination circuit 78. As a result, even when the printer is set to the second maintenance mode, if it is possible to accurately determine whether or not a nozzle is abnormal, a suction purge can be performed appropriately based on the signal from the determination circuit 78 to restore the abnormal nozzle.

[0077] On the other hand, if the absolute value |K-Kt| of the difference between the number of abnormal nozzles K and the stored number of abnormal nozzles Kt is equal to or greater than the threshold value Kr, it is not possible to accurately determine whether or not a nozzle is abnormal, and there is a high possibility that the ink properties are significantly different from when the first maintenance mode is set, so a strong purge is performed, which discharges more ink than a normal purge. This ensures that the abnormal nozzles are restored.

[0078] Furthermore, in Modification 1, if the number K of abnormal nozzles obtained from the results of the inspection process executed in the second maintenance mode is less than [Kt+Ks], this number of abnormal nozzles is stored as Kt in the flash memory 84. Furthermore, in Modification 2, if the absolute value |K-Kt| is less than the threshold value Kr in the second maintenance mode, this number of abnormal nozzles is stored as Kt in the flash memory 84. However, this is not limited to this. In Modifications 1 and 2, only the number of abnormal nozzles obtained from the results of the inspection process executed in the first maintenance mode may be stored as Kt in the flash memory 84.

[0079] Furthermore, in the second maintenance mode, when suction purging based on the result of the inspection process is not performed, maintenance of the inkjet head 4 is not limited to being performed by periodically performing suction purging. In the second maintenance mode, when suction purging based on the result of the inspection process is not performed, maintenance of the inkjet head may be performed by performing suction purging when a condition other than a condition related to the result of the inspection process and a condition that a predetermined time has passed since the previous suction purging is met ("a condition other than a condition related to the signal output from the signal output unit" of the present invention).

[0080] Furthermore, in the above embodiment, the first maintenance mode and the second maintenance mode are switched based on whether the ink cartridges 14 of all colors satisfy the predetermined conditions, but the present invention is not limited to this.

[0081] For example, as described above, the suction purge may be configured to selectively discharge either the black ink or the color ink in the inkjet head 4, and the first maintenance mode or the second maintenance mode may be switched individually for the black ink and the color ink based on whether or not a predetermined condition is met. That is, for the black ink, the first maintenance mode may be set when the black ink cartridge 14 meets the predetermined condition, and the second maintenance mode may be set when the predetermined condition is not met. Also, for the color inks, the first maintenance mode may be set when all three color ink cartridges 14 meet the predetermined condition, and the second maintenance mode may be set when none of the color ink cartridges 14 meets the predetermined condition.

[0082] Alternatively, for example, as described above, the suction purge may be configured to discharge ink from the nozzles 10 of each nozzle row 9 individually, and the first maintenance mode and the second maintenance mode may be switched individually for each of the four colors of ink based on whether or not a predetermined condition is met. In other words, for each color of ink, the ink cartridge 14 may be set to the first maintenance mode if the predetermined condition is met, and may be set to the second maintenance mode if the predetermined condition is not met.

[0083] Furthermore, in the above-described embodiment, when the ink cartridge 14 is installed in the cartridge mounting portion 41 and this ink cartridge 14 is authenticated, the first maintenance mode is set after a predetermined amount of ink has been consumed after the ink cartridge 14 is installed. Also, when the ink cartridge 14 is installed in the cartridge mounting portion 41 and this ink cartridge 14 is not authenticated, the second maintenance mode is set after a predetermined amount of ink has been consumed after the ink cartridge 14 is installed. However, this is not limited to this.

[0084] For example, when the ink cartridge 14 is installed in the cartridge mounting portion 41 and the ink cartridge 14 is authenticated, the first maintenance mode may be immediately set. Similarly, when the ink cartridge 14 is installed in the cartridge mounting portion 41 and the ink cartridge 14 is not authenticated, the second maintenance mode may be immediately set.

[0085] Furthermore, in the above-described embodiment, the ink cartridge 14 has a substrate 53, and information about the ink cartridge 14 is stored on the substrate 53, but this is not limited to this. For example, a label with a two-dimensional code (the "information storage section" of the present invention) printed on it may be attached to the surface of the ink cartridge 14, and the information indicated by this two-dimensional code may be information about the ink cartridge 14. In this case, a reading device for reading the two-dimensional code is provided in the cartridge mounting section 41, and information about the ink cartridge 14 is obtained from the two-dimensional code.

[0086] Furthermore, in the above-described embodiment, the predetermined conditions for switching between the first maintenance mode and the second maintenance mode include the condition that the ink cartridge 14 is an authenticated ink cartridge and the condition that the ink cartridge 14 is within a predetermined period from its manufacturing date, but this is not limited to this. The predetermined condition may be only one of these two conditions. Alternatively, the predetermined condition may include at least one of these two conditions, as well as a condition related to the ink supplied to the inkjet head 4 from a different ink cartridge 14. Alternatively, the predetermined condition may include only another condition related to the ink supplied to the inkjet head 4 from the ink cartridge 14 other than these two conditions.

[0087] Furthermore, in the above-described embodiment, the ink cartridge 14 is removably mounted in the cartridge mounting portion 41. When the ink cartridge 14 is mounted in the cartridge mounting portion 41, the mode is selectively set to either the first maintenance mode or the second maintenance mode based on information about the ink cartridge 14 stored on the board 53. However, this is not limited to this.

[0088] For example, instead of the cartridge holder 13 and the four ink cartridges 14 attached thereto, the printer 1 may be provided with an ink tank that is fixed to the printer 1 and is not normally removed from the printer 1. The ink tank may then be refillable with ink by the user.

[0089] In this case, for example, when refilling an ink tank with ink, the user may be prompted to input authentication information and manufacturing date information written on the ink bottle used to refill the ink by operating an operation unit provided on the printer or a PC connected to the printer. Then, based on the input information, it may be determined whether or not predetermined conditions are met, and the printer may be selectively set to either the first maintenance mode or the second maintenance mode.

[0090] Furthermore, even in a configuration in which the ink cartridge 14 is removably mounted in the cartridge mounting portion 41 as in the above-described embodiment, when mounting the ink cartridge 14 in the cartridge mounting portion 41, the user may be prompted to input authentication information and manufacturing date information written on the ink cartridge by operating an operation unit provided on the printer or a PC connected to the printer. Then, based on this input information, it may be determined whether or not predetermined conditions are met, and the printer may be selectively set to either the first maintenance mode or the second maintenance mode.

[0091] Furthermore, in the above-described embodiment, whether or not the nozzle 10 is an abnormal nozzle is determined based on the change in voltage of the detection electrode 76 when an inspection drive is performed to eject ink toward the detection electrode 76 in the cap 71, but this is not limited to this.

[0092] For example, a detection electrode extending vertically may be arranged, and a signal corresponding to the ink ejection state may be output from the judgment circuit depending on the voltage of the detection electrode when ink is ejected from the nozzle 10 so as to pass through an area facing the detection electrode.

[0093] Furthermore, the signal output unit that outputs a signal according to whether or not the nozzle 10 is an abnormal nozzle is not limited to one that outputs a signal according to the electrical change in the electrode when the test drive is performed.

[0094] 10 and 11, a printer 100 has a configuration in which the detection electrode 76, the high-voltage power supply circuit 77, the determination circuit 78, and the resistor are removed from the printer 1, and further has a discharge detection device 101 (the "signal output unit" of the present invention) in place of these. The discharge detection device 101 has a moving member 102, a light-emitting element 103, and a light-receiving element 104.

[0095] The movable member 102 is disposed between the platen 5 and the cap 71 in the scanning direction, and extends in the scanning direction. The length of the movable member 102 in the scanning direction is longer than the length of the region of the inkjet head 4 in which the plurality of nozzles 10 are arranged. The movable member 102 is supported by two guide rails 105 and 106 that extend in the transport direction, and is movable in the transport direction along the guide rails 105 and 106 under the control of the control unit 80.

[0096] The light-emitting element 103 is disposed at the right end in the scanning direction of the upper surface of the movable member 102. The light-receiving element 104 is disposed at the left end in the scanning direction of the upper surface of the movable member 102. Note that the positions of the light-emitting element 103 and the light-receiving element 104 may be reversed from those described above. The light-emitting element 103 emits light toward the light-receiving element 104. The light-receiving element 104 receives the light from the light-emitting element 103 and transmits a signal corresponding to the amount of light to the control unit 80.

[0097] In the third modification, in the inspection process, the carriage 2 is moved so that the plurality of nozzles 10 of the inkjet head 4 are positioned between the light-emitting element 103 and the light-receiving element 104 in the scanning direction, and the movable member 102 is moved so that the position in the transport direction of an area through which light irradiated from the light-emitting element 103 toward the light-receiving element 104 passes is the same as the position in the transport direction of the nozzle 10 for determining whether or not it is an abnormal nozzle, and then the inkjet head 4 is caused to perform an inspection drive for the nozzle 10. That is, in the third modification, the inspection drive is an operation for ejecting ink from the nozzle 10 toward between the light-emitting element 103 and the light-receiving element 104.

[0098] At this time, if ink is ejected from the nozzle 10 by the test drive, the light emitted from the light-emitting element 103 is blocked by the ink, reducing the amount of light received by the light-receiving element 104. On the other hand, if ink is not ejected from the nozzle 10 by the test drive, the light emitted from the light-emitting element 103 is not blocked by the ink, and the amount of light received by the light-receiving element 104 does not change.

[0099] For these reasons, in the third modification, it is possible to determine whether or not the nozzle 10 is an abnormal nozzle based on the amount of light received by the light receiving element 104 when the test drive is performed.

[0100] When ink is ejected from the nozzle 10 by the test drive, the light emitted from the light-emitting element 103 is blocked by the ink, reducing the amount of light received by the light-receiving element 104. This can be used to detect whether or not a nozzle is abnormal. However, with this configuration, the extent to which the ink blocks light varies depending on the properties of the ink. Therefore, in a printer that determines whether or not a nozzle is abnormal in the manner described above, it is very significant to set the printer to the first maintenance mode when certain conditions are met, and to the second maintenance mode when certain conditions are not met.

[0101] In addition, in Modification 3, the light-emitting element 103 and the light-receiving element 104 are arranged at an interval in the scanning direction, and the movable member 102 on which the light-emitting element 103 and the light-receiving element 104 are arranged is movable in the transport direction, but this is not limiting. For example, the light-emitting element 103 and the light-receiving element 104 may be arranged at an interval in the transport direction, and the movable member 102 on which the light-emitting element 103 and the light-receiving element 104 are arranged may be movable in the scanning direction.

[0102] Furthermore, 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 may 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 may be output from the voltage detection circuit to the control unit 80.

[0103] 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.

[0104] 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.

[0105] Furthermore, in the above example, the abnormal nozzle is restored by performing a suction purge, but this is not a limitation. 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 multiple 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 a so-called pressure purge.

[0106] Furthermore, during purging, both suction by the suction pump 72 and pressurization by the pressure pump may be performed.

[0107] Furthermore, the method of recovering a malfunctioning nozzle is not limited to purging. For example, a malfunctioning nozzle may be recovered by flushing the inkjet head 4, which ejects ink from at least the malfunctioning nozzle. In this case, the inkjet head 4 serves as both the "liquid ejection head" and the "ejection means" of the present invention. Alternatively, a malfunctioning nozzle may be recovered by purging and flushing.

[0108] 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.

[0109] 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]

[0110] 1. Printer 4 Inkjet head 8 Maintenance Unit 10 nozzles 72 Suction pump 76 Detection electrode 77 High-voltage power supply circuit 78 Judgment circuit 79 Resistance 80 Control Unit 84 Flash memory 100 printers 101 Discharge detection device 103 Light-emitting element 104 Photodetector

Claims

1. a liquid ejection head having a nozzle; a liquid tank connected to the liquid ejection head; a tank mounting portion to which the liquid tank is removably mounted; a connection flow path that connects the liquid ejection head and the liquid tank; a signal output unit that outputs a signal corresponding to a state of ejection of liquid from the nozzle when the liquid ejection head is driven for inspection to eject liquid from the nozzle; Discharge means for performing a discharge operation to discharge liquid from the nozzle; a control unit, the liquid tank has an information storage unit that stores information about the liquid tank itself; The control unit performing maintenance of the liquid ejection head by selectively executing either a first maintenance process including a process of causing the ejection means to perform the ejection operation based on the signal output from the signal output unit, or a second maintenance process different from the first maintenance process; executes a determination process to determine whether a predetermined condition regarding the liquid supplied from the liquid tank to the liquid ejection head is satisfied based on the information stored in the information storage unit; When the predetermined conditions are met, a first maintenance mode is set in which the liquid ejection head is maintained by executing the first maintenance process after the liquid tank is mounted on the tank mounting portion and an amount of liquid corresponding to the volume of the connection flow path is discharged from the nozzle; When the predetermined condition is not met, A liquid ejection device characterized in that after the liquid tank is mounted to the tank mounting portion, an amount of liquid corresponding to the volume of the connecting flow path is discharged from the nozzle, and then the device is set to a second maintenance mode in which maintenance of the liquid ejection head is performed by executing the second maintenance process.

2. a liquid ejection head having a nozzle; a liquid tank connected to the liquid ejection head; a signal output unit that outputs a signal corresponding to a state of ejection of liquid from the nozzle when the liquid ejection head is driven for inspection to eject liquid from the nozzle; Discharge means for performing a discharge operation to discharge liquid from the nozzle; a control unit, The control unit performing maintenance of the liquid ejection head by selectively executing either a first maintenance process including a process of causing the ejection means to perform the ejection operation based on the signal output from the signal output unit, or a second maintenance process different from the first maintenance process; When a predetermined condition regarding the liquid supplied from the liquid tank to the liquid ejection head is satisfied, a first maintenance mode is set in which maintenance of the liquid ejection head is performed by executing the first maintenance process; When the predetermined condition is not met, a second maintenance mode is set in which maintenance of the liquid ejection head is performed by executing the second maintenance process; In the second maintenance process, The liquid ejection head is not driven for inspection, A liquid ejection device, characterized in that the ejection means is caused to perform the ejection operation based on whether or not a condition different from a condition related to the signal output from the signal output section is satisfied.

3. a liquid ejection head having a plurality of nozzles; a liquid tank connected to the liquid ejection head; a signal output unit that outputs a signal corresponding to a state of ejection of liquid from the nozzle when the liquid ejection head is driven for inspection to eject liquid from the nozzle; Discharge means for performing a discharge operation to discharge liquid from the nozzle; A memory unit; a control unit, The control unit performing maintenance of the liquid ejection head by selectively executing either a first maintenance process including a process of causing the ejection means to perform the ejection operation based on the signal output from the signal output unit, or a second maintenance process different from the first maintenance process; When a predetermined condition regarding the liquid supplied from the liquid tank to the liquid ejection head is satisfied, a first maintenance mode is set in which maintenance of the liquid ejection head is performed by executing the first maintenance process; When the predetermined condition is not met, a second maintenance mode is set in which maintenance of the liquid ejection head is performed by executing the second maintenance process; In the first maintenance process, performing the inspection drive for each of the plurality of nozzles, determining whether or not the nozzle is an abnormal nozzle that is abnormal in ejecting liquid based on the signal output from the signal output unit, and storing the number of the abnormal nozzles in the storage unit; causing the discharge means to perform the discharge operation when the abnormal nozzle is present; In the second maintenance process, performing the inspection drive for each of the plurality of nozzles, and determining whether or not the nozzle is the abnormal nozzle based on the signal output from the signal output unit; If the abnormal nozzles exist and the number of the abnormal nozzles is less than the number of the abnormal nozzles stored in the storage unit plus a predetermined number, causing the ejection means to perform an ejection operation; If the abnormal nozzles exist and the number of the abnormal nozzles is equal to or greater than the number of the abnormal nozzles stored in the storage unit plus a predetermined number, Thereafter, the ejection means is not caused to perform the ejection operation based on the signal output from the signal output unit, A liquid ejection device, characterized in that the ejection means is caused to perform the ejection operation based on a condition different from a condition related to the signal output from the signal output section.

4. a liquid ejection head having a plurality of nozzles; a liquid tank connected to the liquid ejection head; a signal output unit that outputs a signal corresponding to a state of ejection of liquid from the nozzle when the liquid ejection head is driven for inspection to eject liquid from the nozzle; Discharge means for performing a discharge operation to discharge liquid from the nozzle; A memory unit; a control unit, the discharging means selectively performs, as the discharging operation, either a first discharging operation or a second discharging operation in which the amount of liquid discharged is greater than that of the first discharging operation; The control unit performing maintenance of the liquid ejection head by selectively executing either a first maintenance process including a process of causing the ejection means to perform the ejection operation based on the signal output from the signal output unit, or a second maintenance process different from the first maintenance process; When a predetermined condition regarding the liquid supplied from the liquid tank to the liquid ejection head is satisfied, a first maintenance mode is set in which maintenance of the liquid ejection head is performed by executing the first maintenance process; When the predetermined condition is not met, a second maintenance mode is set in which maintenance of the liquid ejection head is performed by executing the second maintenance process; In the first maintenance process, performing the inspection drive for each of the plurality of nozzles, determining whether or not the nozzle is an abnormal nozzle that is abnormal in ejecting liquid based on the signal output from the signal output unit, and storing the number of the abnormal nozzles in the storage unit; causing the discharge means to perform the first discharge operation when the abnormal nozzle is present; In the second maintenance process, performing the test drive for each of the plurality of nozzles, and determining whether or not the nozzle is abnormal based on the signal output from the signal output unit; If the abnormal nozzles are present and the difference between the number of the abnormal nozzles and the number of the abnormal nozzles stored in the storage unit is less than a threshold value, causing the ejection means to perform the first ejection operation; If the difference between the number of abnormal nozzles and the number of abnormal nozzles stored in the storage unit is equal to or greater than the threshold value, A liquid ejection apparatus, characterized in that the ejection means is caused to perform the second ejection operation.

5. a liquid ejection head having a nozzle; a liquid tank connected to the liquid ejection head; a signal output unit that outputs a signal corresponding to a state of ejection of liquid from the nozzle when the liquid ejection head is driven for inspection to eject liquid from the nozzle; Discharge means for performing a discharge operation to discharge liquid from the nozzle; a control unit, The signal output unit An electrode; voltage application means for applying a voltage to the electrodes; outputting a signal corresponding to an electrical change in the electrode when the test drive is performed in a state where a voltage is applied to the electrode by the voltage application means; The control unit performing maintenance of the liquid ejection head by selectively executing either a first maintenance process including a process of causing the ejection means to perform the ejection operation based on the signal output from the signal output unit, or a second maintenance process different from the first maintenance process; When a predetermined condition regarding the liquid supplied from the liquid tank to the liquid ejection head is satisfied, a first maintenance mode is set in which maintenance of the liquid ejection head is performed by executing the first maintenance process; When the predetermined condition is not met, The liquid ejection apparatus is characterized in that the liquid ejection apparatus is set to a second maintenance mode in which maintenance of the liquid ejection head is performed by executing the second maintenance process.

6. a liquid ejection head having a nozzle; a liquid tank connected to the liquid ejection head; a signal output unit that outputs a signal corresponding to a state of ejection of liquid from the nozzle when the liquid ejection head is driven for inspection to eject liquid from the nozzle; Discharge means for performing a discharge operation to discharge liquid from the nozzle; a control unit, The signal output unit a light-emitting unit that irradiates light; a light receiving unit that receives light emitted from the light emitting unit, outputting a signal corresponding to the amount of light received by the light receiving unit when an operation for discharging liquid from the nozzle toward a gap between the light emitting unit and the light receiving unit is performed as the inspection drive; The control unit performing maintenance of the liquid ejection head by selectively executing either a first maintenance process including a process of causing the ejection means to perform the ejection operation based on the signal output from the signal output unit, or a second maintenance process different from the first maintenance process; When a predetermined condition regarding the liquid supplied from the liquid tank to the liquid ejection head is satisfied, a first maintenance mode is set in which maintenance of the liquid ejection head is performed by executing the first maintenance process; When the predetermined condition is not met, The liquid ejection apparatus is characterized in that the liquid ejection apparatus is set to a second maintenance mode in which maintenance of the liquid ejection head is performed by executing the second maintenance process.

7. In the second maintenance process, the control unit The liquid ejection head is not driven for inspection, 2. The liquid ejection device according to claim 1, wherein the ejection means is caused to perform the ejection operation based on whether or not a condition different from a condition related to the signal output from the signal output section is satisfied.

8. a storage unit, the liquid ejection head has a plurality of the nozzles, The control unit In the first maintenance process, performing the inspection drive for each of the plurality of nozzles, determining whether or not the nozzle is an abnormal nozzle that is abnormal in ejecting liquid based on the signal output from the signal output unit, and storing the number of the abnormal nozzles in the storage unit; causing the discharge means to perform the discharge operation when the abnormal nozzle is present; In the second maintenance process, performing the inspection drive for each of the plurality of nozzles, and determining whether or not the nozzle is the abnormal nozzle based on the signal output from the signal output unit; If the abnormal nozzles exist and the number of the abnormal nozzles is less than the number of the abnormal nozzles stored in the storage unit plus a predetermined number, causing the ejection means to perform an ejection operation; If the abnormal nozzles exist and the number of the abnormal nozzles is equal to or greater than the number of the abnormal nozzles stored in the storage unit plus a predetermined number, Thereafter, the ejection means is not caused to perform the ejection operation based on the signal output from the signal output unit, 2. The liquid ejection device according to claim 1, wherein the ejection means is caused to perform the ejection operation based on a condition different from a condition related to the signal output from the signal output section.

9. a storage unit, the liquid ejection head has a plurality of the nozzles, the discharging means selectively performs, as the discharging operation, either a first discharging operation or a second discharging operation in which the amount of liquid discharged is greater than that of the first discharging operation; The control unit In the first maintenance process, performing the inspection drive for each of the plurality of nozzles, determining whether or not the nozzle is an abnormal nozzle that is abnormal in ejecting liquid based on the signal output from the signal output unit, and storing the number of the abnormal nozzles in the storage unit; causing the discharge means to perform the first discharge operation when the abnormal nozzle is present; In the second maintenance process, performing the test drive for each of the plurality of nozzles, and determining whether or not the nozzle is abnormal based on the signal output from the signal output unit; If the abnormal nozzles are present and the difference between the number of the abnormal nozzles and the number of the abnormal nozzles stored in the storage unit is less than a threshold value, causing the ejection means to perform the first ejection operation; If the difference between the number of abnormal nozzles and the number of abnormal nozzles stored in the storage unit is equal to or greater than the threshold value, 2. The liquid ejection apparatus according to claim 1, wherein the ejection means performs the second ejection operation.

10. The signal output unit An electrode; voltage application means for applying a voltage to the electrodes; A liquid ejection device as described in any one of claims 1 to 4 and 6 to 9, characterized in that it outputs a signal corresponding to the electrical change in the electrode when the test drive is performed while a voltage is applied to the electrode by the voltage application means.

11. The signal output unit a light-emitting unit that irradiates light; a light receiving unit that receives light emitted from the light emitting unit, A liquid ejection device as described in any one of claims 1 to 5 and 7 to 9, characterized in that, as the inspection drive, when an operation is performed to eject liquid from the nozzle toward between the light-emitting unit and the light-receiving unit, a signal corresponding to the amount of light received by the light-receiving unit is output.

12. 12. The liquid ejection device according to claim 1, wherein the control unit executes a switching process for switching between the first maintenance mode and the second maintenance mode based on whether the predetermined condition is satisfied.

13. a tank mounting portion to which the liquid tank is removably mounted, the liquid tank has an information storage unit that stores information about the liquid tank itself; The liquid ejection device according to any one of claims 2 to 11, characterized in that the control unit executes a determination process to determine whether the predetermined condition is satisfied based on the information stored in the information storage unit.

14. a liquid ejection head having a nozzle; a liquid tank connected to the liquid ejection head; a tank mounting portion to which the liquid tank is removably mounted; a connection flow path that connects the liquid ejection head and the liquid tank; a signal output unit that outputs a signal corresponding to a state of ejection of liquid from the nozzles when the liquid ejection head is driven for inspection to eject liquid from the nozzles; and a discharge means for performing a discharge operation to discharge the liquid from the nozzle, A maintenance method for a liquid ejection head in a liquid ejection device, wherein the liquid tank has an information storage unit that stores information about the liquid tank, comprising: determining whether a predetermined condition related to the liquid supplied from the liquid tank to the liquid ejection head is satisfied based on the information stored in the information storage unit; When the predetermined conditions are met, after the liquid tank is mounted on the tank mounting portion, and after an amount of liquid corresponding to the volume of the connection flow path is discharged from the nozzle, maintenance of the liquid ejection head is performed by a first maintenance operation including the discharge operation by the discharge means based on a signal output from the signal output portion; When the predetermined condition is not met, A maintenance method for a liquid ejection head, characterized in that after the liquid tank is mounted on the tank mounting portion, an amount of liquid corresponding to the volume of the connecting flow path is discharged from the nozzle, and then maintenance of the liquid ejection head is performed by a second maintenance operation different from the first maintenance operation.

15. a liquid ejection head having a nozzle; a liquid tank connected to the liquid ejection head; a signal output unit that outputs a signal corresponding to a state of ejection of liquid from the nozzles when the liquid ejection head is driven for inspection to eject liquid from the nozzles; a discharge unit that performs a discharge operation to discharge liquid from the nozzles, When a predetermined condition regarding the liquid supplied from the liquid tank to the liquid ejection head is satisfied, performing maintenance of the liquid ejection head by a first maintenance operation including the discharge operation by the discharge means based on the signal output from the signal output unit; When the predetermined condition is not met, performing maintenance of the liquid ejection head by a second maintenance operation different from the first maintenance operation; In the second maintenance operation, The inspection drive is not performed on the liquid ejection head, A maintenance method for a liquid ejection head, wherein the discharge operation by the discharge means is performed based on whether or not a condition different from a condition related to the signal output from the signal output section is satisfied.

16. a liquid ejection head having a plurality of nozzles; a liquid tank connected to the liquid ejection head; a signal output unit that outputs a signal corresponding to a state of ejection of liquid from the nozzles when the liquid ejection head is driven for inspection to eject liquid from the nozzles; A maintenance method for a liquid ejection head in a liquid ejection device including an ejection unit that performs an ejection operation to eject liquid from the nozzles and a storage unit, the method comprising: When a predetermined condition regarding the liquid supplied from the liquid tank to the liquid ejection head is satisfied, performing maintenance of the liquid ejection head by a first maintenance operation including the discharge operation by the discharge means based on the signal output from the signal output unit; When the predetermined condition is not met, performing maintenance of the liquid ejection head by a second maintenance operation different from the first maintenance operation; In the first maintenance operation, performing the inspection drive for each of the plurality of nozzles, determining whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid based on the signal output from the signal output unit, and storing the number of the abnormal nozzles in the storage unit; When the abnormal nozzle is present, the discharge operation is performed by the discharge means; In the second maintenance operation, performing the test drive for each of the plurality of nozzles, and determining whether or not the nozzle is the abnormal nozzle based on the signal output from the signal output unit; If the abnormal nozzles exist and the number of the abnormal nozzles is less than the number of the abnormal nozzles stored in the storage unit plus a predetermined number, performing a discharge operation by the discharge means; If the abnormal nozzles exist and the number of the abnormal nozzles is equal to or greater than the number of the abnormal nozzles stored in the storage unit plus a predetermined number, Thereafter, the ejection operation by the ejection means is not performed based on the signal output from the signal output unit, A maintenance method for a liquid ejection head, wherein the discharge operation by the discharge means is performed based on a condition different from a condition related to the signal output from the signal output section.

17. a liquid ejection head having a plurality of nozzles; a liquid tank connected to the liquid ejection head; a signal output unit that outputs a signal corresponding to a state of ejection of liquid from the nozzles when the liquid ejection head is driven for inspection to eject liquid from the nozzles; Discharge means for performing a discharge operation to discharge liquid from the nozzle; a storage unit, a maintenance method for a liquid ejection head in a liquid ejection device, wherein the ejection unit selectively performs, as the ejection operation, either a first ejection operation or a second ejection operation in which a larger amount of liquid is ejected than in the first ejection operation, When a predetermined condition regarding the liquid supplied from the liquid tank to the liquid ejection head is satisfied, performing maintenance of the liquid ejection head by a first maintenance operation including the discharge operation by the discharge means based on the signal output from the signal output unit; When the predetermined condition is not met, performing maintenance of the liquid ejection head by a second maintenance operation different from the first maintenance operation; In the first maintenance operation, performing the inspection drive for each of the plurality of nozzles, determining whether or not the nozzle is an abnormal nozzle that is abnormal in ejecting liquid based on the signal output from the signal output unit, and storing the number of the abnormal nozzles in the storage unit; When the abnormal nozzle is present, the first discharge operation is performed by the discharge means; In the second maintenance operation, performing the test drive for each of the plurality of nozzles, and determining whether or not the nozzle is abnormal based on the signal output from the signal output unit; If the abnormal nozzles are present and the difference between the number of the abnormal nozzles and the number of the abnormal nozzles stored in the storage unit is less than a threshold value, causing the ejection means to perform the first ejection operation; If the difference between the number of abnormal nozzles and the number of abnormal nozzles stored in the storage unit is equal to or greater than the threshold value, a second discharge operation performed by the discharge means;

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