Liquid dispensing device

Abstract

To accurately determine whether liquid is normally discharged from a nozzle regardless of components of the liquid to be supplied from a liquid tank to a liquid discharge head.SOLUTION: In discharge determination processing (S101), an ink jet head is caused to perform drive for inspection, and it is determined whether ink is normally discharged from a nozzle on the basis of whether an amplitude value D being difference between a maximum value and a minimum value of a discharge determination signal outputted at that time is equal to or more than a threshold T. A flash memory stores information of a function T=f(Dh) showing a relation between a representative value Dh of the amplitude value D and the threshold T. In threshold setting processing (S102), the next discharge determination processing sets the threshold T to be compared with the amplitude value D on the basis of the representative value Dh of the amplitude value D of the discharge determination signal outputted during the discharge determination processing, and the function.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] As an example of a liquid ejection device that ejects liquid from nozzles, Patent Document 1 describes an inkjet printer that performs recording by ejecting ink from nozzles. The inkjet printer described in Patent Document 1 ejects ink from a nozzle while a potential difference is generated between an electrode in a flushing unit and a nozzle plate. When ink is ejected from a nozzle, the inkjet printer compares the output level of a signal output from a voltage detection circuit connected to the electrode with a threshold value to determine whether the ink was ejected correctly. Patent Document 1 also describes a device in which the threshold value is changed in accordance with a change in the output level of the signal output from the voltage detection circuit due to a decrease in the potential difference between the electrode in the flushing unit and the nozzle plate caused by a deterioration in the insulating performance of the print head or flushing unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-72952 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, ink is supplied to a print head from an ink cartridge. However, there may be slight differences in the ink components between ink cartridges due to factors such as the time elapsed since the ink cartridge was manufactured and the environment in which the ink cartridge was stored. In Patent Document 1, the threshold value used to determine whether ink has been ejected normally is changed depending on the potential difference between the flushing unit electrode and the nozzle plate, as described above. However, the threshold value is set without taking into account differences in the ink components within the ink cartridge. Therefore, depending on the ink components within the ink cartridge, there is a risk that it may not be possible to accurately determine whether ink has been ejected normally.

[0005] An object of the present invention is to provide a liquid ejection device that can more accurately determine whether or not liquid has been ejected from a nozzle. [Means for solving the problem]

[0006] A liquid ejection device of the present invention includes 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 whether or not liquid has been ejected normally from the nozzle when an inspection drive for ejecting liquid from the nozzle is performed in the liquid ejection head, and a control unit, wherein the control unit executes a threshold setting process that sets a threshold to be compared with the value of the signal output from the signal output unit, and an ejection determination process that causes the liquid ejection head to perform the inspection drive and determines whether or not liquid has been ejected normally from the nozzle based on the value of the signal output from the signal output unit and the threshold, and in the threshold setting process, a signal corresponding to the liquid supplied from the liquid tank to the liquid ejection head being a first liquid is output. Regarding the value of the signal output from the signal output unit when the liquid ejection head is driven for inspection in the ejection determination process, If the first condition is satisfied, the threshold value is set to a first threshold value, and the liquid supplied from the liquid tank to the liquid ejection head is The aforementioned The second liquid has different components from the first liquid. Regarding the value of the signal output from the signal output unit when the liquid ejection head is driven for inspection in the ejection determination process, If the second condition is satisfied, the threshold is set to a second threshold different from the first threshold. When the discharge determination process is executed, the threshold setting process is executed after the discharge determination process, and in the threshold setting process, the threshold for the next and subsequent discharge determination processes is set based on the value of the signal output from the signal output unit when the liquid discharge head is driven for inspection in the discharge determination process. . Further, a liquid ejection device of the present invention includes 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 whether or not liquid has been ejected normally from the nozzle when an inspection drive for ejecting liquid from the nozzle is performed in the liquid ejection head, and a control unit, wherein the control unit executes a threshold setting process that sets a threshold to be compared with the value of the signal output from the signal output unit, and an ejection determination process that causes the liquid ejection head to perform the inspection drive and determines whether or not liquid has been ejected normally from the nozzle based on the value of the signal output from the signal output unit and the threshold, and in the threshold setting process, a liquid supplied from the liquid tank to the liquid ejection head is determined to be a first liquid in the ejection determination process. If a first condition regarding the value of the signal output from the signal output unit when the liquid ejection head is caused to perform the test drive is satisfied, the threshold is set to a first threshold; if a second condition regarding the value of the signal output from the signal output unit when the liquid ejection head is caused to perform the test drive in the ejection determination process is satisfied, which corresponds to the liquid supplied from the liquid tank to the liquid ejection head being a second liquid having a different composition from the first liquid, the threshold is set to a second threshold different from the first threshold; when predetermined conditions are satisfied, the ejection determination process and the threshold setting process are executed, and in the threshold setting process, the threshold for the next and subsequent ejection determination processes is set based on the value of the signal output from the signal output unit when the liquid ejection head is caused to perform the test drive in the ejection determination process. a signal output unit that outputs a signal according to whether or not liquid has been normally ejected from the nozzle when a test drive is performed to eject liquid from the nozzle in the liquid ejection head; an information receiving unit that receives information about the liquid tank; a tank mounting unit to which the liquid tank is detachably mounted; a connection flow path that connects the nozzle and the liquid tank mounted on the tank mounting unit; and a control unit, wherein the control unit performs a threshold setting process that sets a threshold value to be compared with the value of the signal output from the signal output unit, and controls the liquid ejection head to perform the test drive and determine whether or not liquid has been normally ejected from the nozzle based on the value of the signal output from the signal output unit and the threshold value. and an ejection determination process that determines whether or not the liquid tank is a first liquid, and in the threshold setting process, if a first condition for the liquid tank is satisfied, which corresponds to the liquid being supplied from the liquid tank to the liquid ejection head being a first liquid, the threshold is set to a first threshold, and if a second condition for the liquid tank is satisfied, which corresponds to the liquid being supplied from the liquid tank to the liquid ejection head being a second liquid having components different from the first liquid, the threshold is set to a second threshold that is different from the first threshold, and in the threshold setting process, when the liquid tank is attached to the tank attachment section, the threshold is determined based on the information, and when an amount of liquid corresponding to the volume of the connecting flow path is discharged from the nozzle after the liquid tank is attached to the tank attachment section, the threshold is set to the determined value. [Effects of the Invention]

[0007] In the present invention, a threshold value is set, and whether liquid has been ejected normally from the nozzle is determined based on the value of the signal output from the signal output unit when the liquid ejection head is driven for testing and the set threshold value. At this time, if a first condition corresponding to the liquid supplied from the liquid tank to the liquid ejection head being a first liquid is satisfied, the threshold value is set to a first threshold value. On the other hand, if a second condition corresponding to the liquid supplied from the liquid tank to the liquid ejection head being a second liquid is satisfied, the threshold value is set to a second threshold value. As a result, in the present invention, it is possible to accurately determine whether liquid has been ejected normally from the nozzle, regardless of whether the liquid supplied from the liquid tank to the liquid ejection head is the first liquid or the second liquid. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a printer according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] 3A and 3B are diagrams for explaining electrodes arranged in a cap and the connection relationship between the electrodes and a high-voltage power supply circuit and a signal processing circuit. [Figure 4] FIG. 1(a) is a diagram showing the signal output from the signal processing circuit when ink is ejected from the nozzle during test drive, and FIG. 1(b) is a diagram showing the signal output from the signal processing circuit when ink is not ejected from the nozzle during test drive. [Figure 5] FIG. 2 is a block diagram showing the electrical configuration of the printer. [Figure 6] 10A is a flowchart showing the flow of processing for performing the discharge determination processing and the threshold setting processing, and FIG. 10B is a diagram for explaining a function showing the relationship between the representative value Dh of the amplitude value D and the threshold T. [Figure 7]10 is a flowchart showing the flow of processing for performing a discharge determination process and a threshold setting process in a second embodiment. [Figure 8] 10A and 10B are diagrams illustrating a cartridge mounting section and an ink cartridge according to a third embodiment. [Figure 9] 11 is a flowchart showing the flow of processing when an ink cartridge is mounted in a cartridge mounting portion in the third embodiment. [Figure 10] 10 is a diagram for explaining a table in which a representative value Dh of the amplitude value D is associated with a threshold value T. FIG. [Figure 11] 10 is a diagram for explaining a method of setting a threshold value T based on the distribution of amplitude values ​​D when ink is ejected and when it is not ejected from a nozzle. FIG. [Figure 12] 10 is a diagram for explaining a method for setting a threshold value T based on the distribution of amplitude values ​​D when ink is ejected from a nozzle. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] [First embodiment] A first preferred embodiment of the present invention will now be described.

[0010] <Overall printer configuration> As shown in FIG. 1, the printer 1 (the "liquid ejection device" of the present invention) according to the first embodiment includes a carriage 2, a subtank 3, an inkjet head 4 (the "liquid ejection head" of the present invention), a platen 5, conveying rollers 6 and 7, a maintenance unit 8, etc.

[0011] The carriage 2 is supported by two guide rails 11 and 12 that extend in the scanning direction. In the following description, the right and left sides of the scanning direction are defined as shown in FIG. 1. The carriage 2 is connected to a carriage motor 86 (see FIG. 5) via a belt or the like (not shown). When the carriage motor 86 is driven, the carriage 2 moves in the scanning direction along the guide rails 11 and 12.

[0012] 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.

[0013] As shown in FIG. 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. The cartridge holder 13 also has an installation sensor 39 in each cartridge mounting portion 41. The installation sensor 39 outputs a signal indicating whether an ink cartridge 14 is installed in the cartridge mounting portion 41. The installation sensor 39 is, for example, a transmission-type photomicrosensor having a light-emitting element and a light-receiving element spaced apart in the scanning direction. When an ink cartridge 14 is not installed in the cartridge mounting portion 41, light emitted from the light-emitting element is received by the light-receiving element. When an ink cartridge 14 is installed in the cartridge mounting portion 41, the ink cartridge 14 is located between the light-emitting element and the light-receiving element, and light emitted from the light-emitting element is blocked by the frame of the ink cartridge 14, so that the light is not received by the light-receiving element. The mounting sensor 39 outputs a signal indicating whether or not the ink cartridge 14 is mounted in the cartridge mounting portion 41, the signal being indicative of whether or not light is received by the light receiving element.

[0014] 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.

[0015] The inkjet head 4 is mounted on the carriage 2 and connected to the lower end of the subtank 3. The inkjet head 4 is supplied with the four colors of ink from the subtank 3. The inkjet head 4 ejects ink from a plurality of nozzles 10 formed on its lower surface, a nozzle face 4a. More specifically, the plurality of nozzles 10 are arranged in the transport direction to form nozzle rows 9, and on the nozzle face 4a, four nozzle rows 9 are aligned in the scanning direction. Black, yellow, cyan, and magenta inks are ejected from the plurality of nozzles 10 in that order, starting from the nozzles constituting the nozzle row 9 on the right side in the scanning direction.

[0016] Here, in the first embodiment, any one of the four ink cartridges 14 corresponds to the "first tank" of the present invention. The nozzle 10 that ejects ink supplied from this ink cartridge 14 corresponds to the "first nozzle" of the present invention. Furthermore, any one of the four ink cartridges 14 other than the ink cartridge 14 that corresponds to the first tank corresponds to the "second tank" of the present invention. The nozzle 10 that ejects ink supplied from this ink cartridge 14 corresponds to the "second nozzle" of the present invention.

[0017] The platen 5 is disposed below the inkjet head 4 and faces the multiple nozzles 10. The platen 5 extends over the entire length of the recording paper P 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 platen 5 in the transport direction. The transport roller 7 is disposed downstream of the inkjet head 4 and 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.

[0018] The maintenance unit 8 includes a cap 71, a suction pump 72, and a waste liquid tank 73. The cap 71 is disposed to the right of the platen 5 in the scanning direction. When the carriage 2 is positioned at a maintenance position to the right of the platen 5 in the scanning direction, the multiple nozzles 10 face the cap 71.

[0019] The cap 71 is also connected to a cap lifting mechanism 88 (see FIG. 5). When the cap lifting mechanism 88 is driven, the cap 71 moves up and down. When the carriage 2 is positioned at the maintenance position, where the plurality of nozzles 10 and the cap 71 face each other, the cap 71 is raised by the cap lifting mechanism 88, whereby the upper end of the cap 71 comes into close contact with the nozzle surface 4a, and the plurality of nozzles 10 are covered by the cap 71. When the cap 71 is lowered, the plurality of nozzles 10 are not covered by the cap 71. Note that the cap 71 does not necessarily have to cover the plurality of nozzles 10 by coming into close contact with the nozzle surface 4a. For example, the cap 71 may cover the plurality of nozzles 10 by coming into close contact with a frame (not shown) or the like that is arranged around the nozzle surface 4a of the inkjet head 4.

[0020] The suction pump 72 is a tube pump or the like, and is connected to the cap 71 and the waste liquid tank 73. In the maintenance unit 8, when the suction pump 72 is driven with the cap 71 in place, it is possible to perform a so-called suction purge, which discharges ink from the inkjet head 4 through the multiple nozzles 10. The ink discharged by the suction purge is stored in the waste liquid tank 73.

[0021] 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, 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.

[0022] As shown in FIG. 3, an electrode 76 having a rectangular planar shape is disposed within the cap 71. The electrode 76 is connected to a high-voltage power supply circuit 77 via a resistor 79. The high-voltage power supply circuit 77 applies a predetermined voltage (e.g., approximately 600 V) to the electrode 76 when performing the test drive described below. Meanwhile, the inkjet head 4 is held at ground potential. This generates a predetermined potential difference between the inkjet head 4 and the electrode 76. A signal processing circuit 78 is connected to the electrode 76. The signal processing circuit 78 includes a differentiation circuit and outputs an ejection determination signal corresponding to the voltage of the electrode 76. However, the signal output from the signal processing circuit 78 may be a current signal. In the first embodiment, the electrode 76, the high-voltage power supply circuit 77, the signal processing circuit 78, and the resistor 79 together correspond to the "signal output unit" of the present invention.

[0023] In the above-described cap state, when a voltage is applied to the electrode 76 by the high-voltage power supply circuit 77 and the inspection driving described below is not performed, the voltage of the signal output from the signal processing circuit 78 becomes the voltage V0 shown in Figures 4(a) and (b).

[0024] Furthermore, in the first embodiment, after the inkjet head 4 is in the capped state, a voltage is applied to the electrode 76 by the high-voltage power supply circuit 77, and then the inkjet head 4 can be driven for testing to eject ink from the nozzle 10 toward the electrode 76.

[0025] When ink is ejected from the nozzle 10 by the test drive, the ink ejected from the nozzle 10 is charged. As a result, the charged ink approaches the electrode 76, and the potential of the electrode 76 changes until the ink lands on the electrode 76. Then, after the charged ink lands on the electrode 76, the potential of the electrode 76 attenuates and returns to the potential before the ink was ejected.

[0026] 4(a), the signal output from the signal processing circuit 78 rises from voltage V0 to voltage V1, which is greater than voltage V0, then drops to voltage V2, which is less than voltage V0, and then repeats rising and falling while attenuating before returning to voltage V0. As a result, the signal output from the signal processing circuit 78 becomes a signal whose maximum value is voltage V1 and whose minimum value is voltage V2.

[0027] On the other hand, if ink is not ejected from the nozzle 10 by the test drive, the signal output from the signal processing circuit 78 will hardly change from the voltage V0, as shown in FIG. 4(b).

[0028] In this way, in the first embodiment, the signal output from the signal processing circuit 78 differs depending on whether or not ink has been ejected from the nozzle 10 by the test drive. Then, in the first embodiment, this fact is used to determine whether or not ink has been ejected normally from the nozzle 10, as will be described later.

[0029] In the first embodiment, a predetermined voltage is applied to the electrode 76, the inkjet head 4 is held at ground potential, and the signal processing circuit 78 outputs a signal corresponding to the voltage of the electrode 76. However, the present invention is not limited to this. Alternatively, the electrode 76 may be held at ground potential and a predetermined voltage may be applied to the inkjet head 4, thereby generating a potential difference between the electrode 76 and the inkjet head 4, and the signal processing circuit 78 may be connected to the inkjet head 4 and output an ejection determination signal corresponding to the voltage of the inkjet head 4.

[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 (referred to as a "storage unit" in this invention), 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 signals from an attachment sensor 39, a signal processing circuit 78, and the like.

[0031] In addition to the components described above, the printer 1 also includes a display unit 69 and an operation unit 68. The display unit 69 is, for example, a liquid crystal display provided on the housing of the printer 1. The control unit 80 controls the display unit 69 to display necessary information on the display unit 69. The operation unit 68 is, for example, buttons provided on the housing of the printer 1, a touch panel provided on the display unit 69, etc. The operation unit 68 receives signals based on user operations and transmits the received signals to the control unit 80.

[0032] 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.

[0033] <Processing during recording> Next, a description will be given of the processing of the control unit 80 when recording on recording paper P in the printer 1. In the first embodiment, for example, when a user performs an operation on the operation unit 68 or a PC (not shown) connected to the printer 1 to instruct recording on recording paper P, a recording command instructing recording is sent from the operation unit 68, the PC, etc. to the control unit 80, and the control unit 80 receives this recording command.

[0034] Then, upon receiving a recording command, the control unit 80 controls the conveyance motor 87 and a paper feeder (not shown) to supply the recording paper P. Next, the control unit 80 drives the carriage motor 86 to move the carriage 2 in the scanning direction, while repeatedly causing the inkjet head 4 to eject ink from the multiple nozzles 10 toward the recording paper P, and the conveyance motor 87 to drive the conveyance rollers 6 and 7 to convey the recording paper P a predetermined distance in the conveyance direction, thereby performing recording on the recording paper P. After recording on the recording paper P is completed, the control unit 80 drives the conveyance motor 87 to cause the conveyance rollers 6 and 7 to eject the recording paper P on which recording has been completed.

[0035] <Discharge Determination Process and Threshold Setting Process> Next, we will explain the discharge determination process for determining whether ink has been normally discharged from the nozzle 10, and the threshold setting process for setting a threshold used in the discharge determination process. In the first embodiment, the discharge determination process and the threshold setting process are executed by performing processing according to the flow of Fig. 6(a).

[0036] The flow of FIG. 6(a) is started, for example, when a user operates the operation unit 68 or a PC (not shown) connected to the printer 1 to instruct a test to determine whether ink is being ejected normally from the nozzles 10, and the control unit 80 receives a signal corresponding to the operation. Alternatively, the control unit 80 starts the processing of the flow of FIG. 6(a) in response to, for example, the installation of an ink cartridge 14 in the cartridge installation unit 41. Here, "starting the processing of the flow of FIG. 6(a) in response to the installation of an ink cartridge 14 in the cartridge installation unit 41" means that, after the control unit 80 receives a signal from the installation sensor 39 indicating that the ink cartridge 14 has been installed in the cartridge installation unit 41, recording on the recording paper P, suction purging, etc. are performed, and the total amount of ink discharged from the multiple nozzles 10 to which ink is supplied from the ink cartridge 14 reaches a predetermined amount, and the ink in the ink cartridge 14 reaches the nozzles 10, the processing of the flow of FIG. 6(a) is started. The predetermined amount is an amount corresponding to the volume of the flow path connecting the ink cartridge 14 attached to the cartridge mounting portion 41 and the nozzles 10, which is formed by the tube 15, the flow path in the subtank 3, and the flow paths other than the nozzles 10 in the inkjet head 4. Furthermore, the control unit 80 determines whether the total amount of ink discharged from the multiple nozzles 10 to which ink is supplied from the ink cartridge 14 has reached a predetermined amount, for example, based on the number of times ink is ejected from each nozzle 10, the number of times suction purges have been performed, etc. after the ink cartridge 14 has been attached to the cartridge mounting portion 41.

[0037] 6(a) in more detail, the control unit 80 executes a discharge determination process (S101). In the discharge determination process, the control unit 80 sequentially drives the inkjet head 4 for each of the plurality of nozzles 10 of the inkjet head 4 for testing, and determines whether ink has been normally discharged from the nozzle 10 based on the signal output from the signal processing circuit 78 when the test drive is performed. Specifically, if an amplitude value D, which is the difference between the maximum and minimum values ​​of the signal output from the signal processing circuit 78 when the test drive is performed, is equal to or greater than a threshold value T, the control unit 80 determines that ink has been normally discharged from the nozzle 10, and if the amplitude value D is less than the threshold value T, the control unit 80 determines that ink has not been normally discharged from the nozzle 10.

[0038] Here, the maximum value is a portion of a determination period of a predetermined length that begins at the timing when the test drive is performed, and is the maximum value in a period that includes the timing at which the value of the signal output from the signal processing circuit 78 is estimated to be maximum when ink is ejected from the nozzles 10 by the test drive. Alternatively, the maximum value may be the maximum value in the entire determination period. Furthermore, the minimum value is the minimum value in a portion of the determination period that includes the timing at which the value of the signal output from the signal processing circuit 78 is estimated to be minimum when ink is ejected from the nozzles 10 by the test drive. Alternatively, the minimum value may be the minimum value in the entire determination period.

[0039] Next, the control unit 80 executes a threshold setting process (S102). In the threshold setting process, the control unit 80 sets a threshold T to be compared with the amplitude value D in the next discharge determination process. Therefore, the threshold T to be compared with the amplitude value D in the current discharge determination process is the threshold T set in the threshold setting process after the previous discharge determination process.

[0040] In the first embodiment, information on a function T=f(Dh) indicating the relationship between a representative value Dh of the amplitude values ​​D and a threshold value T, as shown in FIG. 6B, is stored in the flash memory 84. The representative value Dh of the amplitude values ​​D is, for example, the average value, median value, or the like of the amplitude values ​​D of signals output from the signal processing circuit 78 when test driving is performed on each of the multiple nozzles 10 of the inkjet head 4 in the ejection determination process, and when it is determined that ink has been ejected normally from the nozzle 10. In the first embodiment, the above function is stored individually for each color of ink. Alternatively, the above function for black ink and the above function common to the three color inks may be stored. Alternatively, the above function common to the four color inks may be stored.

[0041] In the threshold setting process, a threshold value T to be compared with the amplitude value D in the next discharge determination process is set individually for each nozzle 10 that discharges ink of each color based on a representative value Dh of the amplitude value D in the discharge determination process of S101 and a function T=f(Dh). In other words, a threshold value T is set individually for the first nozzle and the second nozzle.

[0042] As a result, for example, when the representative value Dh is Dh1, the threshold value T is set to T1, and when the representative value Dh is Dh2, the threshold value T is set to T2. The condition that the representative value Dh is Dh1 is an example of the "first condition" of the present invention, and T1 is an example of the "first threshold" of the present invention. Furthermore, the ink supplied from the ink cartridge 14 to the inkjet head 4 when the representative value Dh is Dh1 is an example of the "first liquid" of the present invention. Furthermore, the condition that the representative value Dh is Dh2 is an example of the "second condition" of the present invention, and T2 is an example of the "second threshold" of the present invention. Furthermore, the ink supplied from the ink cartridge 14 to the inkjet head 4 when the representative value Dh is Dh2 is an example of the "second liquid" of the present invention.

[0043] <Effects> In the first embodiment, a threshold value T is set, and whether ink has been ejected normally from the nozzles 10 is determined based on the signal output from the signal processing circuit 78 when the inkjet head 4 is driven for testing and the set threshold value T. At this time, if a first condition corresponding to the ink supplied from the ink cartridge 14 to the inkjet head 4 being the first liquid is satisfied, the threshold value T is set to a first threshold value. On the other hand, if a second condition corresponding to the ink supplied from the ink cartridge 14 to the inkjet head 4 being the second liquid is satisfied, the threshold value T is set to a second threshold value different from the first threshold value. This makes it possible to accurately determine whether ink has been ejected normally from the nozzles 10, regardless of whether the ink supplied from the ink cartridge 14 to the inkjet head 4 is the first liquid or the second liquid.

[0044] Furthermore, in the first embodiment, the first condition and the second condition are conditions for the signal output from the signal processing circuit 78 when the inkjet head 4 is driven for testing. Furthermore, in the first embodiment, a threshold setting process is executed when the ejection determination process is executed. Then, in the threshold setting process, a threshold T to be used in the next ejection determination process is set based on the signal output from the signal processing circuit 78 when the inkjet head 4 is driven for testing in the ejection determination process. This makes it possible to accurately determine whether ink has been ejected normally from the nozzles 10 in the next ejection determination process based on the set threshold T.

[0045] Furthermore, in the first embodiment, the maximum and minimum values ​​of the signal output from the signal processing circuit 78 when the inkjet head 4 is driven for testing vary depending on the components of the ink in the inkjet head 4. Therefore, in the first embodiment, the first and second conditions are conditions regarding the difference between the maximum and minimum values ​​of the signal output from the signal output unit when the liquid ejection head is driven for testing. Then, a threshold value is set based on the difference between the maximum and minimum values ​​of the signal output from the signal output unit when the liquid ejection head is driven for testing. This makes it possible to accurately determine whether ink is being ejected normally from the nozzles 10 based on the set threshold value.

[0046] Furthermore, in the first embodiment, the signal output from the signal processing circuit 78 when the inkjet head 4 is driven for testing changes when ink is ejected from the nozzle 10, and changes very little when ink is not ejected from the nozzle 10. Therefore, in the first embodiment, the threshold value T is set based on the signal output from the signal processing circuit 78 when it is determined that ink has been ejected normally from the nozzle 10. This makes it possible to accurately determine whether ink has been ejected normally from the nozzle 10 based on the set threshold value T.

[0047] Furthermore, in the first embodiment, information on a function that associates a representative value Dh of the amplitude value D of the signal output from the signal processing circuit 78 when ink is normally ejected from the nozzles 10 by test driving with a threshold value T is stored. Then, the threshold value T is set based on the representative value Dh when test driving is performed for each of the multiple nozzles 10 in the inkjet head 4 and the information on the function. This makes it possible to set the threshold value T to an appropriate value.

[0048] Furthermore, the four colors of ink are supplied to the inkjet head 4 from separate ink cartridges 14. Furthermore, the four colors of ink have different components. Therefore, in the first embodiment, a threshold value T is set individually for each nozzle 10 that ejects each color of ink. This makes it possible to accurately determine, based on the threshold value T, whether or not ink has been ejected correctly for each nozzle 10 that ejects each color of ink.

[0049] [Second embodiment] Next, a second preferred embodiment of the present invention will be described. The second embodiment also relates to a printer 1 similar to that of the first embodiment. However, unlike the first embodiment, in the second embodiment, the control unit 80 executes the discharge determination process and the threshold setting process by performing the process according to the flow of FIG.

[0050] 7 will be described in more detail. The control unit 80 executes the same discharge determination process as S101 in the first embodiment (S201). Subsequently, if the flow of FIG. 7 was initiated in response to the installation of the ink cartridge 14 in the cartridge mounting portion 41 (S202: YES), the control unit 80 executes the same threshold setting process as S102 in the first embodiment (S203). However, the threshold value T set in the threshold setting process of S203 is the threshold value T to be compared with the amplitude value D in subsequent discharge determination processes. On the other hand, if the flow of FIG. 7 was not initiated in response to the installation of the ink cartridge 14 in the cartridge mounting portion 41 (S202: NO), the control unit 80 terminates the process without executing the threshold setting process. As a result, in the second embodiment, the discharge determination process and the threshold setting process are executed in response to the installation of the ink cartridge 14 in the cartridge mounting portion 41. In the second embodiment, the condition that, after the ink cartridge 14 is mounted in the cartridge mounting portion 41, the total amount of ink discharged from the multiple nozzles 10 to which ink is supplied from the ink cartridge 14 reaches a predetermined amount corresponds to the "predetermined condition" of the present invention.

[0051] <Effects> In the second embodiment, when predetermined conditions are satisfied, a discharge determination process and a threshold setting process are executed. Then, in the threshold setting process, a threshold T for subsequent discharge determination processes is set based on the value of the signal output from the signal processing circuit 78 when the inkjet head 4 is driven for testing in the discharge determination process. This makes it possible to accurately determine whether ink has been discharged from the nozzles 10 based on the set threshold T in subsequent discharge determination processes.

[0052] Furthermore, in the second embodiment, when the ink cartridge 14 mounted in the cartridge mounting portion 41 is replaced, air may enter from the cartridge mounting portion 41, preventing ink from being ejected normally from the nozzles 10. Furthermore, when the ink cartridge 14 mounted in the cartridge mounting portion 41 is replaced, the composition of the ink supplied to the inkjet head 4 from the ink cartridge 14 before replacement may differ from the composition of the ink supplied to the inkjet head 4 from the ink cartridge 14 after replacement.

[0053] Therefore, in the second embodiment, the predetermined condition is that after an ink cartridge 14 is installed in the cartridge mounting portion 41, the total amount of ink discharged from the multiple nozzles 10 that discharge ink supplied from that ink cartridge 14 reaches a predetermined amount. In other words, the predetermined condition includes the condition that an ink cartridge 14 is installed in the cartridge mounting portion 41. This makes it possible to check whether ink is no longer being discharged normally from the nozzles 10 due to the replacement of the ink cartridge 14 installed in the cartridge mounting portion 41. In this case, a threshold setting process is executed, and the threshold T is set to a value corresponding to the ink components in the replaced ink cartridge 14. This makes it possible to accurately determine whether ink is being discharged normally from the nozzles 10 based on the set threshold T in the next and subsequent discharge determination processes.

[0054] [Third embodiment] Next, a preferred third embodiment of the present invention will be described. Like the first and second embodiments, the third embodiment also relates to a printer 1. However, in the third embodiment, as shown in FIG. 8 , 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 installed in the cartridge installation portion 41. The substrate 53 is an IC chip or the like, and stores information about the ink cartridge 14. The information about the ink cartridge 14 includes information indicating the model number of the ink cartridge 14, the manufacturing date of the ink cartridge 14, the color of the ink cartridge 14, and the amount of ink stored in the ink cartridge 14. Correspondingly, a contact portion 43 (the "information receiving unit" of the present invention) is provided on the ceiling surface 41a of the cartridge installation portion 41. The contact portion 43 is connected to the control unit 80, which will be described later. When the ink cartridge 14 is installed in the cartridge installation portion 41, the substrate 53 is connected to the contact portion 43. As a result, information about the ink cartridge 14 stored on the substrate 53 is received by the contact unit 43 and sent to the control unit 80 .

[0055] In the third embodiment, a user operates the operation unit 68 or a PC (not shown) connected to the printer to instruct a test to determine whether ink is being ejected normally from the nozzles 10, and when the control unit 80 receives a signal corresponding to the operation, it executes an ejection determination process similar to S101 in the first embodiment. Also, in the third embodiment, when an ink cartridge 14 is installed in the cartridge installation unit 41, the control unit 80 executes the process of the flow in FIG.

[0056] 9 in more detail, the control unit 80 acquires information about the ink cartridge 14 stored on the substrate 53 and received by the contact unit 43 (S301), determines the threshold value T based on the acquired information, and stores the value in the flash memory 84 (S302). For example, a table that associates information about the ink cartridge 14, such as the model number of the ink cartridge 14, the time elapsed since the date of manufacture, information indicating the color of the ink cartridge 14, and information indicating the amount of ink stored in the ink cartridge 14, with the threshold value T is stored in the flash memory 84, and in S302, the threshold value T is determined based on the acquired information and the table. However, at the time of S302, the threshold value T has only been determined, and the threshold value T remains set to the previous value.

[0057] In the third embodiment, the threshold value T determined in S302 when the acquired information satisfies a certain first condition corresponds to the "first threshold value" of the present invention, and the ink supplied from the ink cartridge 14 to the inkjet head 4 at this time corresponds to the "first liquid" of the present invention. In the third embodiment, the threshold value T determined in S302 when the acquired information satisfies a second condition different from the first condition corresponds to the "second threshold value" of the present invention, and the ink supplied from the ink cartridge 14 to the inkjet head 4 at this time corresponds to the "second liquid" of the present invention.

[0058] Next, after the ink cartridge 14 is mounted in the cartridge mounting portion 41, the control unit 80 waits until recording on the recording paper P, suction purging, etc. are performed, and the total amount of ink discharged from the multiple nozzles 10 to which ink is supplied from the ink cartridge 14 reaches a predetermined amount (S303: NO). The predetermined amount is an amount corresponding to the volume of the flow path (the "connecting flow path" of the present invention) connecting the ink cartridge 14 mounted in the cartridge mounting portion 41 to the nozzles 10, which is formed by the tube 15, the flow path in the subtank 3, and the flow path other than the nozzles 10 in the inkjet head 4. In S303, the control unit 80 also determines whether the total amount of ink discharged from the multiple nozzles 10 to which ink is supplied from the ink cartridge 14 reaches a predetermined amount, for example, based on the number of times ink is ejected from each nozzle 10, the number of times suction purging is performed, etc. after the ink cartridge 14 is mounted in the cartridge mounting portion 41.

[0059] Then, when the total amount of ink discharged from the nozzles 10 reaches a predetermined amount (S303: YES), the control unit 80 sets the threshold value T to the value determined in S302 (S304). Note that in the third embodiment, the processes of S301 to S304 correspond to the "threshold value setting process" of the present invention.

[0060] <Effects> The ink components stored in the ink cartridges 14 may differ. In the third embodiment, information about the ink cartridges 14 is received, and a threshold value T is set based on the received information. This makes it possible to accurately determine whether ink has been ejected normally from the nozzles 10 based on the set threshold value T.

[0061] Furthermore, in the third embodiment, the ink cartridge 14 has a substrate 53 on which information about the ink cartridge 14 is stored, and is removably mounted in the cartridge mounting portion 41. Then, in the third embodiment, when the ink cartridge 14 is mounted in the cartridge mounting portion 41, a contact portion 43 provided in the cartridge mounting portion 41 receives the information stored on the substrate 53 and sets the threshold value T based on the received information. This makes it possible to accurately determine whether ink has been ejected normally from the nozzles 10 based on the set threshold value T.

[0062] Furthermore, in the third embodiment, after the ink cartridge 14 is mounted in the cartridge mounting portion 41, when an amount of ink corresponding to the volume of the connecting flow path connecting the ink cartridge 14 mounted in the cartridge mounting portion 41 and the nozzle 10 is discharged from the corresponding nozzle 10, the ink in the ink cartridge 14 reaches the nozzle 10. Therefore, in the third embodiment, when the ink cartridge 14 is mounted in the cartridge mounting portion 41, the threshold value T is determined based on information received from the substrate 53. Thereafter, when an amount of ink corresponding to the volume of the connecting flow path is discharged from the corresponding nozzle 10, the threshold value T is set to the determined value. In this way, it is possible to accurately determine whether or not ink has been ejected normally from the nozzle 10 based on the set threshold value T.

[0063] [Variations] Although the first to third preferred embodiments of the present invention have been described above, the present invention is not limited to the first to third embodiments and various modifications are possible within the scope of the claims.

[0064] In the first embodiment, the threshold setting process is executed each time the discharge determination process is executed, and a threshold value T for comparison with the amplitude value D in the next discharge determination process is set. However, this is not limited to this. For example, the threshold setting process may be executed each time the discharge determination process is executed a predetermined number of times. Alternatively, for example, the threshold setting process may be executed when the discharge determination process is executed for the first time after a predetermined number of sheets of recording paper P have been recorded on since the previous threshold setting process. Alternatively, for example, the threshold setting process may be executed when the discharge determination process is executed for the first time after a predetermined time has elapsed since the previous threshold setting process. Note that the threshold value T set in these cases is the threshold value T for comparison with the amplitude value D in the discharge determination process from the next time onwards until the next time the threshold setting process is executed.

[0065] In the second embodiment, after the ink cartridge 14 is mounted in the cartridge mounting portion 41, the ejection determination process and the threshold setting process are executed when the condition that the total amount of ink discharged from the multiple nozzles 10 that eject ink supplied from the ink cartridge 14 reaches a predetermined amount is met, but this is not limited to this.

[0066] For example, if the length of the path between the ink cartridge mounted in the cartridge mounting portion and the inkjet head 4 is short, such as when the cartridge mounting portion is provided on the carriage 2, the ejection determination process and threshold setting process may be executed immediately when the ink cartridge 14 is mounted in the cartridge mounting portion 41. In this case, the condition that the ink cartridge 14 has been mounted in the cartridge mounting portion 41 corresponds to the "predetermined condition" of the present invention.

[0067] The ejection determination process and the threshold setting process may also be executed when a predetermined condition is met that does not include the condition that the ink cartridge 14 is mounted in the cartridge mounting portion 41. The predetermined condition that does not include the condition that the ink cartridge 14 is mounted in the cartridge mounting portion 41 is, for example, a condition that the number of sheets of recording paper P recorded after the previous threshold setting process has reached a predetermined number, or a condition that the elapsed time since the previous threshold setting process has reached a predetermined time.

[0068] Furthermore, in the first and second embodiments, the threshold value T is set based on the representative value Dh of the amplitude value D and the function T=f(Dh), but this is not limitative.

[0069] In Modification 1, information on a table associating the range of a representative value Dh of the amplitude value D with a threshold value T, as shown in FIG. 10, is stored in flash memory 84. Note that the table in FIG. 10 shows three ranges for the representative value Dh and three corresponding threshold values ​​T, but the representative value Dh and threshold value T in this table may each have two or four or more types. Also, in Modification 1, a separate table is stored for each color of ink. Alternatively, the table for black ink and the table common to the three color inks may be stored. Alternatively, a common table may be stored for the four color inks.

[0070] In Modification 1, the control unit 80 performs processing in accordance with the flow of Fig. 6(a), as in the first embodiment. Alternatively, the control unit 80 performs processing in accordance with the flow of Fig. 7, as in the second embodiment. Then, in the threshold setting process, a threshold T is set for each nozzle 10 that ejects ink of each color, based on the representative value Dh of the amplitude value D in the ejection determination process and the table of Fig. 10.

[0071] In Modification 1, for example, the condition that the representative value Dh is within any one of the three ranges shown in the table of Fig. 10 is an example of the "first condition" of the present invention. The threshold value T corresponding to the case where the representative value Dh is within the one range is an example of the "first threshold" of the present invention. The ink supplied from the ink cartridge 14 to the inkjet head 4 when the representative value Dh is within the one range is an example of the "first liquid" of the present invention.

[0072] In addition, in Modification 1, the condition that the representative value Dh is in a range other than the one of the three ranges shown in the table of Fig. 10 is an example of a "second condition" of the present invention. The threshold value T corresponding to the representative value Dh being in the other range is an example of a "second threshold" of the present invention. The ink supplied from the ink cartridge 14 to the inkjet head 4 when the representative value Dh is in the other range is an example of a "second liquid" of the present invention.

[0073] In the first modification, information in a table correlating a representative value Dh of the amplitude value D of the signal output from the signal processing circuit 78 when ink is normally ejected from the nozzles 10 due to test driving with a threshold value T is stored, and the threshold value T is set based on the representative value Dh of the signal output from the signal processing circuit 78 when it is determined that ink has been normally ejected from the nozzles 10 when test driving is performed for each of the multiple nozzles 10 in the inkjet head 4, and the information in the table. This makes it possible to set the threshold value T to an appropriate value.

[0074] Furthermore, the threshold value may be set by a method other than that described above, based on a representative value Dh of the amplitude values ​​D for the nozzles 10 that ejected ink normally during the test drive. Furthermore, for example, the threshold value T may be set using the amplitude values ​​D for all the nozzles 10, including the nozzles 10 that ejected ink normally and the nozzles 10 that did not eject ink normally.

[0075] Furthermore, the threshold value T may be set based on the distribution of amplitude values ​​D when the plurality of nozzles 10 are driven for testing. For example, in Modification 2, the control unit 80 performs processing according to the flow of FIG. 6(a), as in the first embodiment. Alternatively, the control unit 80 performs processing according to the flow of FIG. 7, as in the second embodiment. Then, in the threshold setting process, the control unit 80 generates information on the distribution of amplitude values ​​D when the plurality of nozzles 10 of the inkjet head 4 are driven for testing in the discharge determination process of S101, as shown in FIG. 11. The information shown in FIG. 11 is generated by dividing the range of amplitude values ​​D into a plurality of sections (K=1, 2, ...) each having a width of ΔD. K The amplitude value D indicates the number of nozzles 10 within the section E. K Within means that the amplitude value D is D K More than D K+1 (=D K +ΔD).

[0076] 11, the control unit 80 acquires information on a first range R1 in which the number of distributed nozzles 10 is the largest, and information on a second range R2 in which the number of distributed nozzles 10 is the second largest after the first range. The first range R1 in which the number of distributed nozzles 10 is the section E in which the number of distributed nozzles 10 is the largest. N Multiple consecutive sections E including K And each section E K A plurality of sections E each including a predetermined number of nozzles 10 K The second range R2 in which the number of distributed nozzles 10 is the second largest after the first range R1 is the section E included in the first range R1. K Section E excluding K Among these, the section E in which the number of nozzles 10 is distributed is the largest M Multiple consecutive sections E including K And each section E K A plurality of sections E each including a predetermined number of nozzles 10 K is.

[0077] Then, the control unit 80 determines the minimum value of the first range R1 (D in the case of FIG. 11).N-2 ) and the maximum value of the second range R2 (D in the case of Figure 11) M+2 ) is set as the threshold T. For example, the average value between the minimum value of the first range R1 and the maximum value of the second range R2 is set as the threshold T.

[0078] In Modification 2, the threshold T that is set when the first range R1 and the second range R2 satisfy a certain first condition corresponds to the "first threshold" of the present invention, and the ink supplied from the ink cartridge 14 to the inkjet head 4 at this time corresponds to the "first liquid" of the present invention. In Modification 2, the threshold T that is set when the first range R1 and the second range R2 satisfy a second condition different from the first condition corresponds to the "second threshold" of the present invention, and the ink supplied from the ink cartridge 14 to the inkjet head 4 at this time corresponds to the "second liquid" of the present invention.

[0079] In the second modification, the threshold value T can be appropriately set based on the distribution of the amplitude values ​​D of the signals output from the signal processing circuit 78 when the inspection drive is performed for each of the plurality of nozzles 10.

[0080] Furthermore, the amplitude value D when ink is ejected normally from the nozzles 10 is often a value within a certain range, and the amplitude value D when ink is not ejected normally from the nozzles 10 is often a value within a range different from the certain range. Therefore, the amplitude values ​​of the signal output from the signal processing circuit 78 when test driving is performed on each of the multiple nozzles 10 are mostly distributed between two mutually different ranges.

[0081] Therefore, in Modification 2, information on a first range R1 in which the amplitude values ​​are most widely distributed and information on a second range R2 in which the amplitude values ​​D are second most widely distributed after the first range R1 are obtained based on the distribution of the amplitude values ​​D of the signal output from the signal processing circuit 78 when test driving is performed for each of the multiple nozzles 10. A value between the first range R1 and the second range R2 is then set as the threshold T. This makes it possible to determine whether the amplitude value D falls within the first range R1 or the second range R2 based on whether the amplitude value D is greater than the threshold T, and to accurately determine whether ink has been ejected normally from the nozzles 10.

[0082] In Modification 3, the control unit 80 performs processing according to the flow of FIG. 6(a), as in the first embodiment. Alternatively, the control unit 80 performs processing according to the flow of FIG. 7, as in the second embodiment. Then, in the threshold setting process, the control unit 80 generates information on the distribution of amplitude values ​​D for the multiple nozzles 10 of the inkjet head 4, as in Modification 2, as shown in FIG. 12. Furthermore, the control unit 80 obtains information on a first range R1, as described in Modification 2, based on the distribution shown in FIG. 12. Furthermore, the control unit 80 obtains information on a section E in the first range R1, which has the largest number of nozzles 10. N Obtain information on section E N The representative value Da of the amplitude value D in N and D N+1 and the average value (=[D N +D N+1 ] / 2).

[0083] In addition, in Modification 3, a reference amplitude value D0, which is a reference value for the amplitude value D when ink is ejected from the nozzle 10 by test driving, and a reference threshold value T0, which is a reference value for the corresponding threshold value T, are set in advance and stored in the flash memory 84. In Modification 3, the threshold value T is set to [T0 + (Da - D0)]. FIG. 12 shows a case where the representative value Da is greater than the reference amplitude value D0, and in this case, the threshold value T is set to a value greater than the reference threshold value T0. On the other hand, unlike FIG. 12, when the representative value Da is smaller than the reference amplitude value D0, the threshold value T is set to a value smaller than the reference threshold value T0. Also, unlike FIG. 12, when the representative value Da is equal to the reference amplitude value D0, the threshold value T is set to the reference threshold value T0.

[0084] In Modification 3, the threshold value T that is set when the first range R1 satisfies a certain first condition corresponds to the "first threshold value" of the present invention, and the ink supplied from the ink cartridge 14 to the inkjet head 4 at this time corresponds to the "first liquid" of the present invention. In Modification 2, the threshold value T that is set when the first range R1 satisfies a second condition different from the first condition corresponds to the "second threshold value" of the present invention, and the ink supplied from the ink cartridge 14 to the inkjet head 4 at this time corresponds to the "second liquid" of the present invention.

[0085] In the case of the third modification, too, the threshold value T can be appropriately set based on the distribution of the amplitude values ​​D of the signals output from the signal processing circuit 78 when the inspection drive is performed for each of the plurality of nozzles 10.

[0086] Furthermore, the threshold value T may be set by a method other than those described in variants 2 and 3, based on the distribution of the amplitude values ​​D of the signal output from the signal processing circuit 78 when test driving is performed for each of the multiple nozzles 10.

[0087] Furthermore, in the first and second embodiments, the threshold value T is set based on the amplitude value D, which is the difference between the maximum and minimum values ​​of the signal output from the signal processing circuit 78 when test driving is performed. Then, in the subsequent ejection determination process, it is determined whether ink has been ejected normally from the nozzle 10 based on whether the amplitude value D of the signal output from the signal processing circuit 78 when test driving is performed is equal to or greater than the threshold value T. However, this is not limited to this. For example, the threshold value may be set based on the maximum value of the signal output from the signal processing circuit 78 when test driving is performed. Then, in the subsequent ejection determination process, it may be determined whether ink has been ejected normally from the nozzle 10 based on whether the maximum value of the signal output from the signal processing circuit 78 when test driving is performed is equal to or greater than the threshold value. Alternatively, for example, the threshold value may be set based on the minimum value of the signal output from the signal processing circuit 78 when test driving is performed. Then, in the subsequent ejection determination process, it may be determined whether ink has been ejected normally from the nozzle 10 based on whether the minimum value of the signal output from the signal processing circuit 78 when test driving is performed is equal to or less than the threshold value.

[0088] Furthermore, in the third embodiment, when the ink cartridge 14 is mounted in the cartridge mounting portion 41, the threshold value T is determined based on information obtained from the substrate 53. Then, thereafter, when a predetermined amount of ink is discharged from the nozzles 10, the threshold value T is set to the determined threshold value T, but this is not limited to this. For example, if the length of the path between the ink cartridge mounted in the cartridge mounting portion and the inkjet head 4 is short, such as when the cartridge mounting portion is provided on the carriage 2, the threshold value may be set based on information obtained from the substrate 53 immediately when the ink cartridge 14 is mounted in the cartridge mounting portion 41.

[0089] Furthermore, in the third embodiment, information about the ink cartridge 14 is obtained by receiving information stored on the substrate 53 provided in the ink cartridge 14 at the contact portion 43 provided in the cartridge mounting portion 41, but this is not limited to this. For example, the ink cartridge 14 may be provided with a barcode or two-dimensional code indicating its own information (the "information storage portion" of the present invention), and the cartridge mounting portion 41 may be provided with a reader that reads this barcode or two-dimensional code (the "information receiving portion" of the present invention). Then, information about the ink cartridge 14 may be received by reading the barcode or two-dimensional code with the reader.

[0090] Alternatively, for example, a serial number for identifying the ink cartridge 14 may be printed on the surface of the ink cartridge 14, and when the user operates the operation unit 68 to input the serial number, the control unit 80 may obtain information about the ink cartridge 14 based on the input serial number. In this case, the operation unit 68 corresponds to the "information receiving unit" of the present invention.

[0091] In the above example, the threshold value T is set individually for each nozzle that ejects each color of ink, but this is not limiting. For example, a threshold value may be set individually for the nozzles 10 that eject black ink (the "first nozzles" of the present invention) and the nozzles 10 that eject color (yellow, cyan, magenta) ink (the "second nozzles" of the present invention). Alternatively, a single common threshold value may be set for all the nozzles 10 of the inkjet head 4.

[0092] In addition, in the first and second embodiments, when the inkjet head 4 is driven for testing, it is determined whether or not ink is ejected normally from the nozzle 10 based on an ejection determination signal output from the signal processing circuit 78 in response to a change in voltage from the nozzle 10 to the electrode 76 arranged in the cap 71, but this is not limited to this.

[0093] For example, instead of electrode 76, an electrode may be provided that extends vertically and faces the space below nozzle 10 when carriage 2 is located at the maintenance position. Then, signal processing circuit 78 may output a signal ("ejection determination signal" of the present invention) that corresponds to a change in voltage of the electrode when inspection driving is performed with carriage 2 located at the maintenance position. In this case, the combination of the vertically extending electrode, high-voltage power supply circuit 77, signal processing circuit 78, and resistor 79 corresponds to the "signal output unit" of the present invention.

[0094] Alternatively, for example, an optical sensor (the "signal output unit" of the present invention) may be provided that directly detects ink ejected from the nozzles 10 and outputs a signal (the "ejection determination signal" of the present invention) in accordance with the detection result when the carriage 2 is positioned at a predetermined position such as a maintenance position. Then, based on the signal output from this optical sensor, it may be determined whether ink has been ejected normally from the nozzles 10.

[0095] Alternatively, for example, as described in Patent Publication No. 4929699, a voltage detection circuit (the "signal output unit" of the present invention) that detects changes in voltage when ink is ejected from the nozzles can be connected to a plate on which the nozzles of the inkjet head are formed, and whether or not ink has been ejected normally from the nozzles can be determined based on the signal output from the voltage detection circuit when an operation to eject ink from the nozzles is performed with the carriage moved to the inspection position.

[0096] 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.

[0097] Furthermore, in the first to third embodiments, the test drive is performed on all the nozzles 10 of the inkjet head 4 to determine whether ink is ejected normally from the nozzles 10, but this is not limited to this. For example, the test drive may be performed on only some of the nozzles 10 of the inkjet head 4, such as every other nozzle 10 in each nozzle row 9, to determine whether ink is ejected normally from the nozzles 10. Then, for the other nozzles 10, it may be estimated whether ink is ejected normally from the nozzles 10 based on the determination results for the some of the nozzles 10.

[0098] In the above example, the discharge determination signal output from the signal processing circuit 78 is a signal that indicates whether or not ink has been discharged from the nozzle 10. When the discharge determination signal indicates that ink has been discharged from the nozzle 10, it is determined that ink has been normally discharged from the nozzle 10. However, this is not limited to this. The discharge determination signal may be a signal that indicates a discharge mode other than whether or not ink has been discharged, such as the ink discharge direction or discharge speed. When the discharge determination signal indicates that ink has been discharged from the nozzle 10 in a predetermined discharge mode, it may be determined that ink has been normally discharged from the nozzle 10.

[0099] In the above example, the printer is provided with a cartridge mounting section 41, and the ink cartridge 14 is removably mounted in the cartridge mounting section 41, but this is not limiting. For example, the printer may be provided with an ink tank (the "liquid tank" of the present invention) fixed to the housing, and may be provided with a refill port for refilling the ink tank with ink.

[0100] In the second embodiment, if the printer is equipped with an ink tank as described above, the ejection determination process and the threshold setting process may be executed, for example, when the ink tank is refilled with ink. In other words, the condition that the ink tank is refilled with ink may be set as the predetermined condition.

[0101] In the third embodiment, if the printer is equipped with an ink tank as described above, for example, a serial number for identifying the ink bottle is printed on the surface of the ink bottle that stores the ink to refill the ink tank, and when the user operates the operation unit 68 to input the serial number, the control unit 80 obtains information about the ink bottle based on the input serial number, and sets a threshold value based on the obtained information.

[0102] 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 in the scanning direction.

[0103] 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]

[0104] 1: Printer 10: Nozzle 4: Inkjet head 76: Electrode 77: High voltage power supply circuit 78: Signal processing circuit 79: Resistance 80: Control unit 84: Flash memory

Claims

1. 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 whether or not liquid has been normally ejected from the nozzle when a test drive for ejecting liquid from the nozzle is performed in the liquid ejection head; a control unit, The control unit a threshold setting process for setting a threshold to be compared with the value of the signal output from the signal output unit; performing an ejection determination process in which the liquid ejection head is driven for inspection, and the liquid is normally ejected from the nozzle based on the value of the signal output from the signal output unit and the threshold value; In the threshold setting process, If a first condition is satisfied regarding the value of the signal output from the signal output unit when the liquid ejection head is driven for testing in the ejection determination process, the first condition corresponds to the liquid supplied from the liquid tank to the liquid ejection head being a first liquid, the threshold value is set to a first threshold value; when a second condition is satisfied regarding the value of the signal output from the signal output unit when the liquid ejection head is driven for inspection in the ejection determination process, the second condition corresponding to the liquid supplied from the liquid tank to the liquid ejection head being a second liquid having a different component from the first liquid, the threshold value is set to a second threshold value different from the first threshold value; When the discharge determination process is executed, the threshold value setting process is executed after the discharge determination process, A liquid ejection device characterized in that, in the threshold setting process, the threshold for the next and subsequent ejection judgment processes is set based on the value of the signal output from the signal output unit when the liquid ejection head is driven for inspection in the ejection judgment 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 according to whether or not liquid has been normally ejected from the nozzle when a test drive for ejecting liquid from the nozzle is performed in the liquid ejection head; a control unit, The control unit a threshold setting process for setting a threshold to be compared with the value of the signal output from the signal output unit; performing an ejection determination process in which the liquid ejection head is driven for inspection, and the liquid is normally ejected from the nozzle based on the value of the signal output from the signal output unit and the threshold value; In the threshold setting process, If a first condition is satisfied regarding the value of the signal output from the signal output unit when the liquid ejection head is driven for testing in the ejection determination process, the first condition corresponds to the liquid supplied from the liquid tank to the liquid ejection head being a first liquid, the threshold value is set to a first threshold value; when a second condition is satisfied regarding the value of the signal output from the signal output unit when the liquid ejection head is driven for inspection in the ejection determination process, the second condition corresponding to the liquid supplied from the liquid tank to the liquid ejection head being a second liquid having a different component from the first liquid, the threshold value is set to a second threshold value different from the first threshold value; When a predetermined condition is satisfied, the ejection determination process and the threshold value setting process are executed. A liquid ejection device characterized in that, in the threshold setting process, the threshold for the next and subsequent ejection judgment processes is set based on the value of the signal output from the signal output unit when the liquid ejection head is driven for inspection in the ejection judgment process.

3. a tank mounting portion to which the liquid tank is removably mounted, 3. The liquid ejection device according to claim 2, wherein the predetermined condition includes a condition that the liquid tank is attached to the tank attachment portion.

4. the first condition and the second condition are conditions regarding a difference between a maximum value and a minimum value of a signal output from the signal output unit when the liquid ejection head is driven for inspection, The control unit A liquid ejection device as described in any one of claims 1 to 3, characterized in that in the threshold setting process, the threshold is set based on the difference between the maximum and minimum values ​​of the signal output from the signal output unit when the liquid ejection head is driven for inspection.

5. The control unit A liquid ejection device as described in any one of claims 1 to 4, characterized in that in the threshold setting process, the threshold is set based on the value of the signal output from the signal output unit when the ejection determination process determines that liquid has been ejected normally from the nozzle.

6. the liquid ejection head has a plurality of the nozzles, a storage unit, the storage unit stores information of a function that associates the threshold value with the value of the signal output from the signal output unit when liquid is normally ejected from the nozzle by the test driving; The control unit A liquid ejection device as described in claim 5, characterized in that in the threshold setting process, the threshold is set based on the value of the signal output from the signal output unit when the liquid ejection head is driven for inspection for each of the multiple nozzles, when it is determined that liquid has been ejected normally from the nozzle, and information about the function.

7. the liquid ejection head has a plurality of the nozzles, a storage unit, the storage unit stores information of a table that associates the threshold value with the value of the signal output from the signal output unit when liquid is normally ejected from the nozzle by the test driving, and The control unit A liquid ejection device as described in claim 5, characterized in that in the threshold setting process, the threshold is set based on the value of the signal output from the signal output unit when the liquid ejection head is driven for inspection for each of the multiple nozzles, when it is determined that liquid has been ejected normally from the nozzle, and on the information in the table.

8. the liquid ejection head has a plurality of the nozzles, The control unit In the threshold setting process, acquiring information on an amplitude value that is the difference between a maximum value and a minimum value of a signal output from the signal output unit when the test drive is performed for each of the plurality of nozzles; The liquid ejection apparatus according to claim 4 , wherein the threshold value is set based on a distribution of the amplitude values ​​for the plurality of nozzles.

9. The control unit In the threshold setting process, acquiring information on a first range in which the amplitude values ​​are most widely distributed and information on a second range in which the amplitude values ​​are second most widely distributed after the first range based on the distribution of the amplitude values ​​for the plurality of nozzles; The liquid ejection device according to claim 8 , wherein the threshold value is set to a value between the first range and the second range.

10. 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 whether or not liquid has been normally ejected from the nozzle when a test drive for ejecting liquid from the nozzle is performed in the liquid ejection head; an information receiving unit that receives information about the liquid tank; a tank mounting portion to which the liquid tank is removably mounted; a connection flow path that connects the nozzle and the liquid tank attached to the tank attachment portion; a control unit, The control unit a threshold setting process for setting a threshold to be compared with the value of the signal output from the signal output unit; performing an ejection determination process in which the liquid ejection head is driven for inspection, and the liquid is normally ejected from the nozzle based on the value of the signal output from the signal output unit and the threshold value; In the threshold setting process, When a first condition for the liquid tank is satisfied, which corresponds to the liquid supplied from the liquid tank to the liquid ejection head being a first liquid, the threshold value is set to a first threshold value; when a second condition for the liquid tank is satisfied, the second condition corresponds to the liquid being a second liquid having a different component from the first liquid, the threshold value being set to a second threshold value different from the first threshold value; In the threshold setting process, determining the threshold value based on the information when the liquid tank is attached to the tank attachment portion; A liquid ejection device characterized in that after the liquid tank is attached to the tank mounting section, the threshold value is set to a determined value when an amount of liquid corresponding to the volume of the connecting flow path is discharged from the nozzle.

11. the liquid tank has an information storage unit that stores the information, a tank mounting portion to which the liquid tank is removably mounted, The liquid ejection device according to claim 10, wherein the information receiving unit is provided in the tank mounting unit and receives the information stored in the information storage unit of the liquid tank mounted in the tank mounting unit.

12. The liquid tanks include a first liquid tank and a second liquid tank, the liquid ejection head has, as the nozzles, a first nozzle that ejects the liquid supplied from the first liquid tank and a second nozzle that ejects the liquid supplied from the second liquid tank; The control unit 12. The liquid ejection apparatus according to claim 1, wherein in the threshold setting process, the threshold is set individually for the first nozzle and the second nozzle.

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