Patent Publication Number: US-2021162771-A1

Title: Liquid ejection device, method of controlling liquid ejection device, and non-transitory computer-readable recording medium therefor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. § 119 from Japanese Patent Application No. 2019-215967 filed on Nov. 29, 2019. The entire subject matter of the application is incorporated herein by reference. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosures relate to a liquid ejection device configured to eject liquid through nozzles. The present disclosures also relate to a method of controlling the liquid ejection device, and a non-transitory computer-readable medium containing computer-executable instructions to be executed by a controller of the liquid ejection device. 
     Related Art 
     An inkjet recording device has been known as an example of a liquid ejection device configured to eject liquid through nozzles. The inkjet recording device is typically configured to eject ink droplets through nozzles to record an image on a sheet. In such an inkjet recording device, a recording head is controlled such that ink droplets are ejected from multiple nozzles sequentially, thereby performing a droplet ejection detecting operation in which it is checked whether each nozzle is an ejection-defective nozzle with use of a droplet ejection detecting device. Such a droplet ejection detecting operation may be performed before printing is performed. 
     SUMMARY 
     According to the above-mentions droplet ejection detecting operation, the recording head is controlled such that the ink droplet is ejected from each of the multiple nozzles in order, and whether each nozzle is the ejection-defective nozzle or not is determined with use of the droplet ejection detecting device, it takes some time to determine whether there exists an ejection-defective nozzle. Therefore, when the droplet ejection detecting operation is performed before the printing is started, there could be a situation where a time period from issuance of a print instruction to the start of printing becomes relatively long. 
     According to aspects of the present disclosures, there is provided a liquid ejection device having a liquid ejection head having multiple nozzles, a determination signal output part configured to output a determination signal corresponding to whether each of the multiple nozzles is an ejection-defective nozzle exhibiting ejection-defectiveness in ejecting liquid, and a controller. The controller is configured to perform receiving a preparation signal, the preparation signal being a signal instructing preparation to eject the liquid, the preparation signal being externally issued upon issuance of an ejection instruction to eject the liquid toward a target medium, starting to receive ejection data after the preparation signal is received, the ejection data being externally transmitted on condition that the ejection instruction is issued and after the preparation signal is issued, and controlling the liquid ejection head to eject the liquid toward the target medium through the multiple nozzles based on the ejection data. After receiving the preparation signal and before completion of receiving the ejection data, the controller is configured to perform controlling the liquid ejection head so that the multiple nozzles eject the liquid, and performing ejection-defectiveness determination by examining at least a part of the multiple nozzles for ejection-defectiveness based on the determination signal. 
     According to aspects of the present disclosures, there is provided a method of controlling a liquid ejection device having a liquid ejection head having multiple nozzles, and a determination signal output part configured to output a determination signal corresponding to whether each of the multiple nozzles is an ejection-defective nozzle exhibiting ejection-defectiveness in ejecting liquid. The method includes receiving a preparation signal, the preparation signal being a signal instructing preparation to eject the liquid, the preparation signal being externally issued upon issuance of an ejection instruction to eject the liquid toward a target medium, starting to receive ejection data after the preparation signal is received, the ejection data being externally transmitted on condition that the ejection instruction is issued and after the preparation signal is issued, and controlling the liquid ejection head to eject the liquid toward the target medium through the multiple nozzles based on the ejection data. After receiving the preparation signal and before completion of receiving the ejection data, the method further includes controlling the liquid ejection head so that the multiple nozzles eject the liquid, and performing ejection-defectiveness determination by examining at least a part of the multiple nozzles for ejection-defectiveness based on the determination signal. 
     According to aspects of the present disclosures, there is provided a non-transitory computer-readable recording medium for a liquid ejection device having a liquid ejection head having multiple nozzles, a determination signal output part configured to output a determination signal corresponding to whether each of the multiple nozzles is an ejection-defective nozzle exhibiting ejection-defectiveness in ejecting liquid, and a controller. The controller is configured to execute instruction contained in the recording medium to control the liquid ejection device to perform receiving a preparation signal, the preparation signal being a signal instructing preparation to eject the liquid, the preparation signal being externally issued upon issuance of an ejection instruction to eject the liquid toward a target medium, starting to receive ejection data after the preparation signal is received, the ejection data being externally transmitted on condition that the ejection instruction is issued and after the preparation signal is issued, and controlling the liquid ejection head to eject the liquid toward the target medium through the multiple nozzles based on the ejection data. After receiving the preparation signal and before completion of receiving the ejection data, the controller is configured to further control the liquid ejection device to perform controlling the liquid ejection head such that the multiple nozzles eject the liquid, and performing ejection-defectiveness determination by examining at least a part of the multiple nozzles for ejection-defectiveness based on the determination signal. 
    
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
         FIG. 1  schematically shows an inner configuration of a printer according to a present embodiment. 
         FIG. 2  explains a relationship among a detection electrode arranged inside a cap, a high-voltage power source circuit and a determination circuit. 
         FIG. 3A  is a graph showing a change of a voltage of the detection electrode when an ink droplet is ejected from a nozzle. 
         FIG. 3B  is a graph showing a change of a voltage of the detection electrode when no ink droplet is ejected from the nozzle. 
         FIG. 4  is a block diagram illustrating an electric configuration of the printer according to the present embodiment. 
         FIG. 5  is a flowchart illustrating a main process when printing is to be performed. 
         FIG. 6  is a flowchart illustrating a recording process which is called in the main process shown in  FIG. 5 . 
         FIG. 7  is a flowchart illustrating an ejection-defectiveness determination process to be performed immediately before the recording process. 
         FIG. 8  is a flowchart illustrating an ejection-defectiveness determination process to be performed at a timing other than a timing which is immediately before the recording process. 
         FIGS. 9A and 9B  show a flowchart illustrating a main process of a printer according to a modified embodiment. 
         FIG. 10  is a block diagram illustrating an electric configuration of a printer according to a second modification of the present embodiment. 
         FIG. 11  is a flowchart illustrating a main process of the printer according to the second modification. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, referring to the accompanying drawings, an embodiment and modifications according to aspects of the present disclosures will be described. 
     Overall Configuration of Printer 
     As shown in  FIG. 1 , a printer  1  according to an embodiment of the present disclosures includes a carriage  2 , a sub-tank  3 , an inkjet head  4 , a platen  5 , conveying rollers  6  and  7 , and a maintenance unit  8 . The printer  1  is an example of a liquid ejection device. The inkjet head  4  is an example of a liquid ejection head. 
     The carriage  2  is supported by guide rails  11  and  12 , each extending in a scanning direction which is a right-left direction in  FIG. 1 . The carriage  2  is connected to a carriage motor  86  (see  FIG. 4 ) via a belt (not shown). As the carriage motor  86  is driven to rotate, the carriage  2  moves, via the belt, in the scanning direction as guided by the guide rails  11  and  12 . In the following description, a right side and a left side in the scanning direction indicated in  FIG. 1  will be referred to. 
     The sub-tank  3  is mounted on the carriage  2 . The printer  1  has a cartridge holder  14 , and four ink cartridges  15  are detachably attached to the cartridge holder  14 . In the four ink cartridges  15 , from the right side one to the left side one, black, yellow, cyan, and magenta inks (which are examples of liquid) are stored. The sub-tank  3  is connected to the four ink cartridges  15  attached to the cartridge holder  14  with four tubes  13 , respectively, thereby four different color inks being supplied from the four ink cartridges  15  to the sub-tank  3 . 
     The inkjet head  4  is mounted on the carriage  2  and is connected to a lower end of the sub-tank  3 . To the inkjet head  4 , the above-described four colors of inks are supplied from the sub-tank  3 . Further, the inkjet head  4  is configured to eject the inks (i.e., ink droplets) from a plurality of nozzles  10  formed on a nozzle surface  4   a,  which is a lower surface of the inkjet head  4 . According to the present embodiment, the plurality of nozzles  10  forms nozzle arrays  9 , each having multiple nozzles  10  aligned in a direction perpendicular to the scanning direction. As shown in  FIG. 1 , the inkjet head  4  according to the present embodiment has four nozzle arrays  9 , which are parallelly aligned in the scanning direction. From the plurality of nozzles  10 , from the rightmost nozzle array  9  toward the left side nozzle array  9 , the black, yellow, cyan, and magenta ink droplets are ejected. 
     The platen  5  is arranged below the inkjet head  4  and faces the plurality of nozzles  10 . The platen  5  extends in the scanning direction over an entire length of a recording sheet P (an example of a target medium) and supports the recording sheet P from below. The conveying roller  6  is arranged on an upstream side, in the conveying direction, with respect to the inkjet head  4  and the platen  5 . The conveying roller  7  is arranged on a downstream side, in the conveying direction, with respect to the inkjet head  4  and the platen  5 . The conveying rollers  6  and  7  are connected to the conveying motor  87  (see  FIG. 4 ) through a well-known gear train. When the conveying motor  87  is driven to rotate, the conveying rollers  6  and  7  are rotated accordingly, thereby the recording sheet P is conveyed in the conveying direction. 
     The maintenance unit  8  is provided with a cap  61 , a suction pump  62 , and a waste liquid tank  63 . The cap  61  is arranged on a right side, in the scanning direction, with respect to the platen  5 . When the carriage  2  is located at a maintenance position, which is on a right side, in the scanning direction, with respect to the platen  5 , the plurality of nozzles  10  faces the cap  61 . 
     The cap  61  is configured to be elevated and lowered by the cap elevating mechanism  88  (see  FIG. 4 ). By elevating the cap  61  with the cap elevating mechanism  88  with the carriage  2  being located at the maintenance position and the plurality of nozzles  10  facing the cap  61 , an upper end of the cap  61  closely contacts the nozzle surface  4   a,  and the plurality nozzles  10  is covered by the cap  61 . It is noted that the cap  61  should not be limited to one which is configured such that the upper end thereof contacts the nozzle surface  4   a  to cover the plurality of nozzles  10 . The cap  61  could be, for example, configured to closely contact a frame or the like (not shown) arranged to surround the nozzle surface  4   a  of the inkjet head  4  to cover the plurality of nozzles  10 . 
     The suction pump  62  is, for example, a tube pump and is connected to the waste liquid tank  63 . In the maintenance unit  8 , by driving the suction pump  62  with the plurality of nozzles  10  being covered by the cap, a suction purge can be performed. The suction purge is an operation to cause the plurality of nozzles  10  to discharge the inks inside the inkjet head  4  by sucking the inks. The inks discharged ink by the suction purge is stored in the waste liquid tank  63 . 
     In the above description, it is expediently explained that the cap  61  covers all of the plurality of nozzles  10 , and thus, by the suction purge, the inks in the inkjet head  4  are discharged from all of the plurality of nozzles  10 . However, the aspects of the present disclosures are not necessarily be limited to such a configuration. For example, the cap  61  may include a part configured to cover the plurality of nozzles constituting the rightmost nozzle alley  9  configured to eject the black ink and another part configured to cover the plurality of nozzles constituting three nozzles arrays  9  arranged on the left side with respect to the rightmost nozzle alley  9  and configured to eject the color inks (i.e., the yellow, the cyan and the magenta inks), and the black ink or the color inks in the inkjet head  4  are selectively discharged. For another example, a cap  61  may be provided for each nozzle array  9 , and the inks may be discharged from the nozzles  10  of the respective nozzle arrays  9 . 
     As shown in  FIG. 2 , inside the cap  61 , a detection electrode  66 , which has a rectangular shape in a plan view, is arranged inside the cap  61 . The detection electrode  66  is connected to a high-voltage power source  67  through a resistor  69 . A particular positive voltage (e.g., approximately 300 V) is applied, by the high-voltage power source  67 , to the detection electrode  66 . On the other hand, the inkjet head  4  is held at ground potential. Accordingly, a particular potential difference is generated between the inkjet head  4  and the detection electrode  66 . Further, a determination circuit  68  is connected to the detection electrode  66 . The determination circuit  68  compares a voltage value of a voltage signal output from the detection electrode  66  with a threshold voltage Vt, and outputs a signal corresponding to the comparison result. 
     Specifically, since a potential difference is generated between the inkjet head  4  and the detection electrode  66 , the ink droplet ejected from the nozzles  10  is charged. When the ink droplet is ejected from the nozzles  10  toward the detection electrodes  66  with the carriage  2  located at the maintenance position, the charged ink droplet approaches the detection electrode  66 , and the voltage value of the detection electrode  66  rises from a voltage value V 1 , which is a voltage when the inkjet head  4  is not driven, to a voltage value V 2  which is higher than the voltage value V 1  until the ink droplet impacts the detection electrode  66 . Then, after the charged ink droplet has impacted the detection electrode  66 , the voltage value of the detection electrode  66  gradually decreases back to the voltage value V 1 . That is, during a driving time period Td of the inkjet head  4 , the voltage value of the detection electrode  66  varies. 
     On the other hand, when the ink droplet is not ejected from the nozzles  10 , the voltage value of the detection electrode  66  does not substantially vary during the driving period Td of the inkjet head  4 , as shown in  FIG. 3B . In order to distinguish a case where the ink droplet is ejected through the nozzles  10  from a case where the ink droplet is not ejected through the nozzles  10 , a threshold value VT is set to the determination circuit  68 , where the threshold value Vt is larger than the voltage value V 1  and less than the voltage value V 2 . Then, the determination circuit  68  compares the maximum voltage value of the voltage signal output by the detection electrode  66  with the threshold value Vt during the driving period Td of the inkjet head  4 , and outputs a determination signal corresponding to the determination result. It is noted that a combination of the determination circuit  66 , the high-voltage power source  67 , the resistor  69  and the determination circuit  68  is an example of a determination signal output circuit. Further, the determination signal output circuit outputs a determination signal corresponding to whether each nozzle  10  is an ejection-defective nozzle that cannot eject an ink droplet. 
     In the present embodiment, the positive potential is applied to the detection electrode by the high-voltage power source  67 . The configuration may be modified such that a negative potential (e.g., approximately −300 V) may be applied to the detection electrode by the high-voltage power source  67 . In this case, when the ink droplets are ejected toward the detection electrode  66  from the nozzles  10  with the carriage  2  being located at the maintenance position, the charged ink droplet approaches the detection electrode  66 . Until the ink droplet impacts the detection electrode  66 , the voltage value V 1  of the detection electrode  66  is lowered from the voltage value V 1 . Then, after the ink droplet impacts the detection electrode  6 , the voltage value of the detection electrode  66  gradually increases and returns to the voltage value V 1 . 
     Electrical Configuration of Printer 
     Next, an electrical configuration of the printer  1  will be described. An operation of the printer  1  is controlled by a controller  80 . As shown in  FIG. 4 , the controller  80  includes a CPU  81 , a ROM  82 , a RAM  83 , a flash memory  84 , an ASIC  85  and the like. The controller  80  controls operations of the inkjet head  4 , the carriage motor  86 , the conveying motor  87 , the cap elevating mechanism  88 , the high-voltage power source  67 , the suction pump  62  and the like. 
     To the controller  80 , the determination signal is input from the determination circuit  68 . Further, printer  1  has a communication port  70 . The communication port  70  is for connecting with external devices such as a PC or a smartphone through, for example, a LAN. The controller  80  performs communication with an external device through the communication port  70 . It is noted that the communication port  70  is for connecting with the external device either by a wired or wireless connection. 
     It is noted that the controller  80  may be configured such that only the CPU  81  performs various processes, only the ASIC  85  performs various processes, or the CPU  71 , cooperating with the ASIC  85 , performs various processes. Further, the controller  80  may be configured such that only one CPU  81  performs each process, or a plurality of CPUs perform each process in a shared manner. Furthermore, the controller  80  may be configured such that a single ASIC  85  performs each process, or a plurality of ASICs performs each process in a shared manner. 
     Control When Recording is Performed 
     Next, a process of recording on the recording sheet P in the printer  1  will be described. In the printer  1 , an image is recorded on the recording sheet P by performing a recording pass and a conveying operation alternately and repeatedly. The recording pass is a process of causing the inkjet head  4  to eject the ink droplets from the multiple nozzles  10  toward the recording sheet P with moving the carriage  2  in the scanning direction. The conveying operation is to move the recording sheet P in the conveying direction. It is noted that, according to the present embodiment, an operation of recording the image on the recording sheet P by alternately performing the recording pass and the conveying operation is an example of an ejection operation. The single recoding pass and the single conveying operation do not need to be performed alternately. For example, depending on a situation where the recording is performed, the conveying operation may be performed after a plurality of recording passes is performed. 
     Further, according to the present embodiment, the printer  1  is configured to record an image on the printing sheet P either in a normal-quality recording mode (which is an example of a first recording mode) or in a high-quality recording mode (which is an example of a second recording mode). 
     According to the present embodiment, on condition that the user instructs recording of the image on the recording sheet P on the PC, the smartphone or the like, which are connected to the printer  1  through the communication port  70 , a preparation signal instructing a preparation for image recordation on the recording sheet P is transmitted from such a device (i.e., the PC, the smartphone or the like) to the printer  1 . Thereafter, image data corresponding to respective recording passes is transmitted, from the device (i.e., the PC, the smartphone, or the like) to the printer  1 , sequentially, in order from the image data corresponding to the first recording pass. It is noted that, according to the present embodiment, the image data corresponding to the first recording pass is an example of ejection data. 
     Correspondingly, the controller  80  starts a main process illustrated in a flowchart shown in  FIG. 5  when the printer  1  is powered on. The main process shown in  FIG. 5  is performed when the printer is being powered on. 
     In the main process, the controller  80  pauses until the preparation signal is received (S 101 : NO). When the preparation signal is received (S 101 : YES), the controller  80  starts an ejection-defectiveness determination process to determine whether each nozzle  10  is the ejection-defective nozzle or not (S 102 ). The ejection-defectiveness determination process will be described in detail later. 
     Next, the controller  80  pauses as long as the ejection-defectiveness determination process has not been completed (S 103 : NO) and the image data of the first recording pass has not been received (S 104 : NO). When the ejection-defectiveness determination process has completed (S 103 : YES) before the image data for the first recording pass is received, the controller  80  waits until the image data of the first recording pass is completed (S 105 : NO). When the image data of the first recording pass has been received (S 105 : YES), the controller  80  proceeds to a recording process in S 110 . 
     When the image data for the initial recording pass has been received (S 104 : YES) before the ejection-defectiveness determination process completes (S 103 : NO), the controller  80  determines whether the recording mode for recording the received image is the high-quality recording mode (S 106 ). The information regarding the recording mode (i.e., whether the recording mode for the received image is the normal-quality recording mode or the high-quality recording mode) is included in the preparation signal, and the controller  80  makes the determination in S 106  based on the information. 
     When it is determined that the recording mode is the normal-quality recording mode (S 106 : NO), the controller  80  instructs to interrupt the ejection-defectiveness determination process (S 107 ). For the nozzles  10  for which the ejection-defectiveness determination process has not been completed, the controller  80  changes a setting for flushing so that a discharging amount of the ink in flushing is increased (S 108 ). Thereafter, the controller  80  proceeds to the recording process in S 110 . 
     When it is determined that the recording mode is the high-quality recording mode (S 106 : YES), the controller  80  pauses until the ejection-defectiveness determination process is completed (S 109 : NO). When the ejection-defectiveness determination process is completed (S 109 : YES), the controller  80  proceeds to the recording process in S 110 . 
     In the recording process (S 110 ), the controller  80  performs the recording process shown in  FIG. 6 . In S 201 , the controller  80  resets a variable N to zero. The variable N represents the number of recording passes having been performed. 
     Next, the controller  80  performs a sheet feeding process (S 202 ). In the sheet feeding process, the controller  80  controls a sheet feeding device and the conveying motor  87  to cause the sheet feeding device and the conveying roller  6  to feed the recording sheet P and to position the recording sheet  6  at a position where the initial recording pass is to be performed. 
     Next, the controller  80  performs the recording pass process (S 203 ). In the recording pass process (S 203 ), the controller  80  controls the carriage motor  86  to move the carriage  2  in the scanning direction, while performs the recording pass to control the inkjet head  4  based on the image data, thereby causing the plurality of nozzles  10  to eject ink droplets toward the recording sheet P. Thus, a one-pass amount of image corresponding to the image data is recorded on the recording sheet P. 
     Next, the controller  80  increments the variable N by one (S 204 ) and determines whether the variable N is equal to a particular value Nth (S 205 ). When it is determined that the variable N is not equal to the particular value Nth, that is, when the variable N is less than the particular value Nth (S 205 : NO), the controller  80  proceeds to S 208 . 
     When the variable N is equal to the particular value Nth (S 205 : YES), the controller  80  performs a flushing process (S 206 ). In the flushing process in S 206 , the controller  80  performs the flushing operation, which is an operation of controlling the carriage motor  86  to move the carriage  2  to the maintenance position, and driving the inkjet head  4  to cause the plurality of nozzles  10  to discharge the ink droplets. At this stage, when there are nozzles  10  of which settings have been changed in S 108  so that the ink discharging amount is increased, the controller  80  controls the inkjet head  4  so that the ink discharging amounts of the nozzles  10  of which settings have been changed are increased in comparison with the ink discharging amount of the other nozzles  10 . It is noted that, according to the present embodiment, the flushing operation is an example of a discharging operation, and the inkjet head  4  performing the flushing operation is an example of a discharging device. 
     After performing the flushing process in S 206 , the controller  80  resets the variable N to zero (S 207 ) and proceeds to S 208 . Thus, according to the present embodiment, during the image recordation on the recording sheet P, the flushing operation is performed at every Nth time execution of the recording pass. 
     In S 208 , the controller  80  determines whether the recording of an image on one sheet of the recording sheet P has completed. When it is determined that the recordation on one sheet of the recording sheet P has not completed (S 208 : NO), the controller  80  performs a conveying process (S 209 ). In the conveying process (S 209 ), the controller  80  controls the conveying motor  87  to cause the conveying rollers  6  and  7  to convey the recording sheet P by a particular distance. Next, the controller  80  pauses until the image data for the next recording pass is received (S 210 : NO). When it is determined that the image data for the next recording pass has been received (S 210 : YES), the controller proceeds to S 203 . 
     When it is determined that the recording of the image on one sheet of the recording sheet P has completed (S 208 : YES), the controller  80  performs a sheet discharging process (S 211 ). In the sheet discharging process (S 211 ), the controller  80  controls the conveying motor  87  to cause the conveying rollers  6  and  7  to discharge the recording sheet P. 
     When it is determined that the recording of all the images has not been completed (S 212 : NO), the controller  80  pauses unit the image data for the next recording pass has been received (S 213 : NO). When the image data for the next recording pass has been received (S 213 : YES), the controller  80  returns to S 202 . When it is determined that the recording of all the images has been completed (S 212 : YES), the controller returns to S 101  of the main process shown in  FIG. 5 . 
     Ejection-defectiveness Determination Immediately Before Recordation 
     Next, an ejection-defectiveness determination performed after receipt of the preparation signal and before completion of receipt of the image data for the first recording pass (hereinafter, simply referred to, occasionally, as “ejection-defectiveness determination immediately before recordation”) will be described. According to the present embodiment, as the controller  80  performs a flowchart shown in  FIG. 7  (i.e., an ejection-defectiveness determination process), the ejection-defectiveness determination immediately before recordation is performed. 
     In S 301 , the controller  80  controls the carriage motor  86  to move the carriage  2  to the maintenance position. Next, the controller  80  retrieves a first order data (S 302 ). The first order data represents the order set to target nozzles  10 , which are subjected to the ejection-defectiveness determination in the ejection-defectiveness determination immediately before recordation and is stored, for example, in the EEPROM  84  or the like in advance. The first order data indicates that the nozzles  10  ejecting the black ink, and then the nozzles  10  ejecting the color inks are set as the target nozzles in this order. Further, the first order data indicates that, for each nozzle array  9 , a target nozzle is set in the order from a nozzle  10  arranged on an outer side, in the conveying direction, toward a nozzle  10  arranged on an inner side in the conveying direction. In other words, the first order data indicates that the nozzles  10  of which ink tends to thicken are set as the target nozzles  10  earlier. 
     According to the present embodiment, in a relationship between the nozzles  10  ejecting the black ink and the nozzles  10  ejecting the color inks, the nozzles  10  ejecting the color inks are examples of first nozzles, while the nozzles ejecting the black ink are examples of second nozzles. Further, in a relationship between two arbitrary nozzles  10  among the plurality of nozzles  10  in each nozzle array  9 , a nozzle  10  arranged more centrally in the conveying direction is an example of a first nozzle, while a nozzle  10  arranged more outside in the conveying direction is an example of a second nozzle. 
     Next, the controller  80  sets one of the plurality of nozzles  10  of the inkjet head  4  as the target nozzle based on the retrieved first order data (S 303 ). The controller  80  controls the inkjet head  4  to cause the target nozzle to eject the ink droplet toward the detection electrode  66  arranged inside the cap  61  (S 304 ). Next, the controller  80  determines whether the target nozzle is the ejection-defective nozzle based on the determination signal output from the determination circuit (S 305 ). 
     When the controller  80  does not receive a determination interrupting instruction (S 306 : NO), and the controller  80  has not completed the ejection-defectiveness determination for all of the plurality of nozzles  10  (S 307 : NO), the controller sets another one of the plurality of nozzles  10  as the target nozzle based on the first order data (S 308 ) and returns to S 304 . 
     When the controller  80  does not receive the determination interrupting instruction (S 306 : NO), and the controller  80  has completed the ejection-defectiveness determination for all of the plurality of nozzles  10  (S 307 : YES), the controller  80  determines whether there are nozzles determined to be the ejection-defective nozzles among all the nozzles  10  of the inkjet head  4  (S 309 ). When the controller  80  has received the determination instruction (S 306 : YES), the controller  80  determines whether there are nozzles determined to be the ejection-defective nozzles among the nozzles for which the abnormal determination has completed (S 309 ). 
     When there is no ejection-defective nozzle (S 309 : NO), the controller  80  terminates the ejection-defectiveness determination process shown in  FIG. 7 . When there is (are) the ejection-defective nozzle(s) (S 309 : YES), the controller  80  causes the ejection-defective nozzles to perform flushing (S 310 ) and terminates the ejection-defectiveness determination process shown in  FIG. 7 . In S 310 , the controller  80  causes the carriage motor  86  to move to the maintenance position and controls the inkjet head  4  to cause the nozzle(s) determined to be the ejection-defective nozzle(s) to discharge the ink droplets (i.e., flushing). 
     Ejection-defectively Determination at Timing Not Immediately Before Recordation 
     Further, according to the embodiment, the ejection-defectiveness determining process is performed at a timing that is not immediately before recordation (e.g., when recordation has not been performed for a certain fixed period). In such a case, the controller  80  performs the ejection-defectiveness determination process in accordance with a flowchart shown in  FIG. 8 . 
     In S 401 , the controller  80  moves the carriage  2  to the maintenance position, as is done in S 301  of  FIG. 7 . Next, the controller  80  retrieves second order data (S 402 ). It is noted that the second order data is data indicating order to be assigned to each target nozzle among the plurality of nozzles  10  in the ejection-defectiveness determination process performed at a timing which is not immediately before recordation, and is stored, for example, in the EEPROM  84 , in advance. The second order data indicates that whether the nozzles  10  ejecting the color inks and the nozzles  10  ejecting the black ink are ejection-defective nozzles in this order. Further, for each nozzle array  9 , the second order data indicates that whether a nozzle  10  is the ejection-defective nozzle is determined from a nozzle  10  arranged at a more central position in the conveying direction toward a nozzle  10  arranged at an end position in the conveying direction. 
     Next, the controller  80  sets one nozzle  10  as the target nozzle based on the second order data (S 403 ) and drives the inkjet head  4  to cause the target nozzle  10  to eject the ink droplet toward the detection electrode  66  arranged inside the cap  61  (S 404 ). 
     When the ejection-defectiveness determination process for all the nozzles  10  has not been completed (S 406 : NO), the controller  80  changes the target nozzle to another nozzle  10  based on the second order data (S 407 ) and returns to S 404 . 
     When the ejection-defectiveness determination process for all the nozzles  10  has been completed (S 406 : YES), the controller  80  determines whether there are nozzles  10 , which are determined to be the ejection-defective nozzles (S 408 ). When there are no nozzles  10  determined to be the ejection-defective nozzles A(S 408 : NO), the controller  80  terminates the ejection-defectiveness determination process shown in  FIG. 8 . When there are one or more nozzles  10  determined to be the ejection-defective nozzle(s) (S 408 : YES), the controller  80  causes the nozzle(s)  10  determined to be the ejection-defective nozzle(s) to eject the ink droplet(s), as is done in S 309  of  FIG. 7 , and terminates the ejection-defectiveness determination process shown in  FIG. 8 . 
     Effects 
     According to the present embodiment, after receiving the preparation signal and before the image data for the first recording pass has been completed, the controller  80  performs the ejection-defectiveness determination process. Thus, in comparison with a case where the ejection-defectiveness determination is performed after receipt of the preparation signal and after the first image data has been received, a time period from an instruction to record an image on the recording sheet P until the recording of the image on the recording sheet P is actually performed can be shortened. 
     According to the present embodiment, the black ink is thickened easier than the color inks. Further, the ink is thickened easier in the nozzles  10 , in each nozzle array  9 , arranged on outer sides in the conveying direction than in the nozzles  10 , in each nozzle array  9 , arranged on the central portion in the conveying direction. On the other hand, since a time period from receipt of the preparation signal to completion of receipt of the image data for the first recording pass is relatively short, the ejection-defectiveness determination process for all the nozzles  10  may not be completed during such a short period. 
     Therefore, according to the present embodiment, the ejection-defectiveness of the nozzle is determined for the nozzles  10  ejecting the black ink and for the nozzles  10  ejecting the color inks in this order in the ejection-defectiveness determination process performed during a period from the preparation signal has been received and before the image data for the first recording pass has been received. Further, the nozzles  10  in each nozzle array  9 , the ejection-defectiveness is determined for the nozzles arranged on the outer sides in the conveying direction. In other words, the ejection-defectiveness of the nozzle is determined from the nozzle  10  in which the ink could thicken easily. Accordingly, the ejection-defectiveness of the nozzles in which the ink is thickened easily can be determined efficiently during the above-described period. 
     When the ejection-defectiveness determination process is performed at a timing which is different from the above-described period, the ejection-defectiveness of the nozzle is determined for the nozzles ejecting the color inks and for the nozzles  10  ejecting the black ink in this order in the ejection-defectiveness determination process. Further, the nozzles  10  in each nozzle array  9 , the ejection-defectiveness is determined for the nozzles arranged on the central portion in the conveying direction. In other words, the ejection-defectiveness of the nozzle is determined from the nozzle  10  in which the ink would not thicken easily. Accordingly, it becomes hardly happen that, during a period when the ejection-defectiveness of a certain nozzle  10  has been completed, and the ejection-defectiveness of another nozzle  10  is being determined, the certain nozzle  10  turns to the ejection-defective nozzle due to thickening of the ink therein. 
     Further, according to the above-described embodiment, when the recording is performed in the normal-quality recording mode, in which the required image quality is not so high, after the preparation signal has received and the image data for the first recording pass has been received before the ejection-defectiveness determination process is completed, the ejection-defectiveness determination process is interrupted during execution, and recordation on the recording sheet P is performed. Thus, it is possible to prevent recordation on the recording sheet P from being delayed. 
     On the other hand, even when the preparation signal has been received and the image data for the first recording pass has been received before the ejection-defectiveness determination process is completed, if recordation is to be performed in the high-quality recording mode, which requires a high image quality, recordation of the image on the recording sheet P is performed after the ejection-defectiveness determination process is completed. Thus, since the ejection-defectiveness determination process has been performed for all the nozzles  10 , the high image quality is guaranteed. 
     When the ejection-defectiveness determination process is interrupted during execution and recordation on the recording sheet P is to be performed, the ejection-defectiveness determination process has not been completed in the flushing, which is to be performed during the recording process. In such a case, for the nozzles  10 , which are not determined to be abnormal or not (i.e., the nozzles  10  which may or may not be ejection-defective nozzles), the ink discharging amount is increased. Thus, although the ink ejection amount in the flushing is increased, even though the ejection-defective nozzles are included among the nozzles  10  which are not determined to be abnormal or not, the ejection-defectiveness can be recovered by performing the flushing. 
     Modifications 
     It is noted that aspects of the present disclosures do not need to be limited to the configuration of the above-described embodiment, but the above-described embodiment can be modified in various ways within aspects of the present disclosures. 
     In the above-described embodiment, in the ejection-defectiveness determination process, the inkjet head  4  is driven such that the ink is ejected from only one nozzle  10 , and it is determined whether the one nozzle  10  is the ejection-defective nozzle or not based on the determination signal. However, aspects of the present disclosures do not need to be limited to the configuration above. For example, according to a first modification, a first ejection-defectiveness determination or a second ejection-defectiveness determination is selectively performed as the ejection-defectiveness determination process. 
     In the first ejection-defectiveness determination process, as in the above-described embodiment, the inkjet head  4  is driven so that an ink droplet is ejected from the one nozzle  10  toward the detection electrode  66  and determines whether the one nozzle  10  is the ejection-defective nozzle or not based on the signal for detection. In the second abnormal detection process, the inkjet head  4  is driven so that ink droplets are ejected simultaneously from a particular number of plural nozzles  10  toward the detection electrode  66  and determines whether the particular number of multiple nozzles  10  include the ejection-defective nozzle based on the determination signal. According to this configuration, a time period necessary to perform the second ejection-defectiveness determination process is shorter than a time period necessary to perform the first ejection-defectiveness determination process for the same number of nozzles  10 . 
     Further, in the first modification, the controller  80  performs a main process illustrated in a flowchart shown in  FIGS. 9A and 9B  when recordation on the recording sheet P is performed. As shown in  FIG. 9A , the controller  80  pauses until the preparation signal is input (S 501 : NO). When the preparation signal is input (S 501 : YES), the controller  80  estimates a receiving time period Tj which is a time period from completion of receipt of the preparation signal till receipt of the image data for the first recording pass is completed (S 502 ). The receiving time period Tj is estimated based on, for example, whether the recording mode is the normal-quality recording mode or the high-quality recording mode. 
     Next, when the estimated receiving time period Tj is longer than a time period T 1  necessary for performing the ejection-defectiveness determination process (S 503 : YES), the controller  80  starts the first ejection-defectiveness determination process (S 504 ). On the other hand, when the estimated receiving time period Tj is shorter than the time T 1  (S 503 : NO), the controller  80  starts the second ejection-defectiveness determination process (S 505 ). After the execution of S 504  or S 505 , the controller  80  performs processes in S 506 -S 513 , which are the same as the processes in S 103 -S 110 , except that the second ejection-defectiveness determination process is performed in S 511 . In S 511 , the controller changes the setting so that the ink discharging amount in the flushing is increased for all the particular number of nozzles  10  which are determined to include the ejection-defective nozzle. 
     In the first modification, when the estimated receiving time period Tj is longer than the time period T 1  necessary for performing the first ejection-defectiveness determination process, the controller  80  starts the first ejection-defectiveness determination process to determine whether the nozzles  10  are ejection-defective nozzles, respectively. Thus, for the plural nozzles  10  of the inkjet head  4 , whether or not the respective nozzles  10  are the ejection-defective nozzles is determined. 
     On the other hand, when the receiving time period Tj is shorter than the time T 1 , the controller  80  performs the second ejection-defectiveness determination process. In this case, for the plural nozzles  10  of the inkjet head  4 , whether or not each of the nozzles  10  is the ejection-defective nozzle cannot be determined, but the time period necessary for performing the ejection-defectiveness determination process can be shortened. 
     In the first modification, the controller  80  estimates the receiving time period Tj, and selectively performs the first ejection-defectiveness determination process or the second ejection-defectiveness determination process depending on whether or not the receiving time period Tj is equal to or longer than the time T 1  necessary for performing the first ejection-defectiveness determination process or not. However, aspects of the present disclosures do not need to be limited to such a configuration. That is, the controller  80  may estimate another time period related to a time period necessary to perform the first ejection-defectiveness determination process (e.g., a time period necessary for receiving the preparation signal and the image data for the first recording pass). Then, depending on whether or not the estimated time period is equal to or longer than the time period necessary for performing the first ejection-defectiveness determination process, the controller  80  may selectively perform the first ejection-defectiveness determination process or the second ejection-defectiveness determination process. 
     According to the first modification described above, the controller  80  controls the inkjet head  4  to eject the ink droplet through one nozzle  10 , and determines whether the one nozzle  10  is the ejection-defective nozzle or not based on the determination signal in the first ejection-defectiveness determination process. Further, the controller  80  drives the inkjet head  4  to cause multiple nozzles  10  to eject the ink droplets, and determines whether or not the multiple nozzles  10  include the ejection-defective nozzle based on the determination signal. Accordingly, the time period necessary for performing the second ejection-defectiveness process is shorter than the time period necessary for performing the first ejection-defectiveness process. However, aspects of the present disclosures do not need to be limited to such a configuration. 
     For example, in each of the first ejection-defectiveness determination process and the second ejection-defectiveness determination process, the controller  80  drives the inkjet head  4  to cause one nozzle  10  to eject the ink droplet, and determines whether the one nozzle  10  is the ejection-defective nozzle or not based on the determination signal in the first ejection-defectiveness determination process. Further, in the first ejection-defectiveness determination process, whether each of all the nozzles  10  of the inkjet head  4  is the ejection-defective nozzle or not is determined. In contrast, in the second ejection-defectiveness determination process, whether each of only the nozzles in which the ink thickens easily is the ejection-defective nozzle or not is determined. According to the above configuration, the time period necessary for performing the second ejection-defectiveness determination process can be shortened than the time period for performing the first ejection-defectiveness determination process. 
     It is noted that the nozzles  10  in which the ink thickens easily are, for example, the nozzles  10  ejecting the black ink, a particular number of nozzles  10  arranged on outer sides, in the conveying direction, of the nozzles  10  of each nozzle array  9 , or the like. 
     In the above-described embodiment, when the image data for the first recording pass has been received before the ejection-defectiveness determination process is completed, whether (1) the ejection-defectiveness determination process is interrupted during execution and the recording process is performed, or (2) the recording process is performed after the ejection-defectiveness determination process is completed, is determined depending on whether recordation is performed in the normal-quality recording mode or the high-quality recording mode. However, aspects of the present disclosures do not need to be limited to such a configuration. 
     In a second modification, as shown in  FIG. 10 , a printer  100  is provided with a LAN port  101  to be connected to a LAN and a facsimile port  102  for a facsimile communication, as communication ports to communicate with an external device. It is noted that the facsimile port  102  is an example of a facsimile communication part. In the second modification, the LAN port  101  is an example of communication other than the facsimile communication part. Further, the LAN port  101  may be configured to be connected to the LAN with either the wired or wireless connection. 
     According to the second modification, when recoding to the recording sheet P is performed, the controller  80  performs a main process, which is illustrated in a flowchart shown in  FIG. 11 . 
     The controller  80  performs processes of S 601 -S 605 , which are the same as the processes in S 101 -S 105  shown in  FIG. 5 . When the image data for the first recording pass has been received (S 604 : YES) before the ejection-defectiveness determination process is completed (S 603 : NO), the controller  80  determines whether the preparation signal and the image data have been received through the facsimile port  102  (S 606 ). 
     When it is determined that the preparation signal and the image data have been received through the LAN port  101  (S 606 : NO), the controller  80  instructs to interrupt the ejection-defectiveness determination process (S 607 ), changes a setting so that the ink discharging amount in the flushing is increased for the nozzles  10  for which the ejection-defectiveness determination process has not been completed (S 608 ), and proceeds to the recording process in S 610 . 
     On the other hand, when the image data and the preparation signal have been received through the facsimile port  102  (S 606 : YES), the controller  80  pauses until the ejection-defectiveness determination process has been completed (S 609 : NO). When the ejection-defectiveness determination process has been completed (S 609 : YES), the controller  80  proceeds to S 610 . It is noted that the recording process in S 610  is the same as S 110  of  FIG. 5 . 
     Generally, in the printer, the received preparation signal and the image data are deleted after recording. However, recording other than that of received facsimile, it is possible to receive the preparation signal and the image data again by transmitting, from the PC, the smartphone, or the like, a request for re-transmission of the preparation signal and the image data, respectively. Thus, recording can be performed based on the image data received again. In such a case, when the image data for the first recording pass has been received after the preparation signal is received and before the ejection-defectiveness determination process is completed, the ejection-defectiveness determination process is interrupted during execution, and recording of the image on the recording sheet P is performed. Thus, it is possible to avoid the starting of recording on the recording sheet P from being delayed. 
     In contrast, it is not ordinarily possible to re-receive the preparation signal and the image data regarding the facsimile. Therefore, recording cannot be performed again. Accordingly, even when the image data for the first recording pass has been received after the preparation signal has been received and before the ejection-defectiveness determination process is completed, the recording on the recording sheet P is performed after the ejection-defectiveness determination is completed. Thus, it is ensured that the image is recorded. 
     According to the above-described embodiment, when the ejection-defectiveness determination process is interrupted during execution, the ink ejection amount of the nozzles  10  for which the ejection-defectiveness determination process has not been performed is increased in comparison with the ink discharging amount of the nozzles  10  for which the ejection-defectiveness determination process has been completed. However, aspects of the present disclosures do not need to be limited to such a configuration. Even when the ejection-defectiveness determination process is interrupted during execution, the ink discharging amount of the nozzles  10  for which the ejection-defectiveness determination process has not been performed and the ink discharging amount of the nozzles  10  for which the ejection-defectiveness determination process has been completed could be the same in the flushing performed during the recording process. 
     It is noted that what is performed during the recording on the recording sheet P is not necessarily be the flushing. For example, the printer  1  may be configured to perform a suction purge for each nozzle array  9  so that the suction purge can be performed during the recording on the printing sheet P. Then, in the suction purge of the nozzle array, which includes the nozzles  10  for which the ejection-defectiveness determination process has not been completed, the ink discharging amount may be increased in comparison with a nozzle array  9 , which does not include the nozzles  10  for which the ejection-defectiveness determination process has not been completed. It is noted that, in the above case, the maintenance unit  8 , which performs the suction purge, is an example of a discharging device. 
     It is noted that a pressure pump may be provided in a middle portion of the tube  13  connecting the sub-tank  3  and the ink cartridge  15 . Alternatively, a pressure pump connected to the ink cartridge may be provided to the printer. Then, a so-called pressure purge may be performed. The pressure purge is an operation to drive the pressure pump, with the plurality of nozzles  10  being covered with the cap  61 , the ink inside the inkjet head  4  is pressurized, thereby the ink inside the inkjet head  4  being discharged through the plurality of nozzles  10 . In this case, a combination of the cap  61  and the pressure pump is an example of the discharging device. 
     When the purge is performed, both the suctioning by the suction pump  62  and the pressurizing by the pressure pump may be performed. In this case, a combination of the maintenance unit  8  and the pressure pump is an example of the discharging device. 
     In the above-described examples, when the image data for the first recording pass has been received before completion of the ejection-defectiveness determination process, whether the ejection-defectiveness determination process is to be interrupted or not is determined depending on a particular condition is satisfied or not. Aspects of the present disclosures do not need to be limited to the above configuration. That is, when the image data for the first recording pass has been received before completion of the ejection-defectiveness determination process, the ejection-defectiveness determination process may always be interrupted. Alternatively, it is configured that the recording process is always performed after the ejection-defectiveness determination process is completed, including a case where the image data for the first recording pass has been received before completion of the ejection-defectiveness determination process. 
     Further, according to the above-described embodiment, in the ejection-defectiveness determination process immediately before the recording, the nozzles  10  ejecting the black ink and the nozzles  10  ejecting the color inks are examined in this order, and further, for the multiple nozzles  10  of each nozzle array  9 , whether the nozzle  10  is the ejection-defective nozzle is determined from the outer side one, in the conveying direction, to the central one in this order. On the other hand, in the ejection-defectiveness determination process performed at a timing which is not immediately before the recording, the nozzles  10  ejecting the color inks and the nozzles  10  ejecting the black ink are examined in this order, and further, for the multiple nozzles  10  of each nozzle array  9 , whether the nozzle  10  is the ejection-defective nozzle is determined from the central one, in the conveying direction, to the outer side one in this order. Aspects of the present disclosures do not need to be limited to such a configuration. 
     In the ejection-defectiveness determination process, which is performed immediately before the recording, the nozzles  10  ejecting the black ink and the nozzles  10  ejecting the color inks may be examined in this order. Further, for the multiple nozzles  10  of each nozzle array  9 , each nozzle may be examined in the order different from the above-explained order to find the ejection-defective nozzles. 
     In the ejection-defectiveness determination process, which is performed at a timing not immediately before the recording, the nozzles  10  ejecting the color inks and the nozzles  10  ejecting the black ink may be examined in this order. Further, for the multiple nozzles  10  of each nozzle array  9 , each nozzle may be examined in the order different from the above-explained order to find the ejection-defective nozzles. 
     In the ejection-defectiveness determination process, which is performed immediately before the recording, the four nozzle arrays  9  may be examined differently from the above-described order. Further, the multiple nozzles of each array may be examiner from the outside ones toward the central side ones, in the conveying direction. 
     In the ejection-defectiveness determination process, which is performed at a timing not immediately before the recording, the four nozzle arrays  9  may be examined in the order different from the above-described order. Further, the multiple nozzles of each array may be examiner from the central ones toward the outside ones, in the conveying direction. 
     In the ejection-defectiveness determination processes which is performed immediately before the recording and performed at a timing not immediately before the recording, the multiple nozzles  10  may be examined in the orders, which are different from the above-described orders and which are different from each other. Optionally, the order of examining the multiple nozzles  10  may be determined, for example, based on ink ejecting conditions of the multiple nozzles  10  when the previous recording was performed. 
     In the ejection-defectiveness determination processes, which is performed immediately before the recording and performed at a timing not immediately before the recording, the multiple nozzles  10  are examined in different orders according to the present embodiment. Aspects of the present disclosures do not need to be limited to such a configuration. For example, regardless of whether the ejection-defectiveness determination processes are performed immediately before the recording or at a timing not immediately before the recording, the multiple nozzles  10  may be examined in a fixed order. 
     In the above-described embodiment, it is determined whether the image data for the first recording pass has been received in S 104  or S 105 . The process may be modified such that, in S 104  and S 105 , it may be determined whether the image data for a particular number (more than one) of successive recording passes including the first one has been received. In such a modification, the image data for the particular number (two or more) of recording passes is an example of the ejection data. Alternatively, in S 104  and S 105 , it may be determined whether the image data for all the recording passes has been received. In such a modification, the image data for all the recording passes is an example of the ejection data. 
     In the above-described embodiment, all the nozzles  10  of the inkjet head  4  are examined in the abnormal determination process. Aspects of the present disclosures do not need to be limited to the configuration. That is, only a part of the plurality of nozzles  10  may be examined. 
     In the above-described embodiment, the ink droplet is ejected, from the nozzle  10 , to the detection electrode  66 , and the determination circuit  68  is configured to output the determination signal depending on the voltage value of the detection electrode  66  when the ink droplet is ejected. Aspects of the present disclosures do not need to be limited to the configuration. 
     For example, a detection electrode extending in the up-down direction may be arranged, and the determination circuit may be configured to output a determination signal depending on a voltage value of the detection electrode when the nozzle  10  is caused to eject the ink droplet so as to pass through an area facing the election electrode. For another example, an optical sensor to detect the ink droplet ejected from the nozzle  10  may be provided, and the optical sensor may be configured to output the determination signal based on the detection result. In this case, the optical sensor is an example of the determination signal output part. 
     Alternatively, a voltage detecting circuit (which is an example of a determination signal output part) configured to detect a variation of voltage when the ink droplet is ejected from the nozzle may be connected to the plate on which the nozzles may be formed, and the voltage detecting circuit may be configured to output the determination signal to the controller  80 . Such a configuration is disclosed in the United States Patent Provisional Publication No. 2007-0139461 A1 (filed on Dec. 7, 2006), the disclosures of which are incorporated herein by reference. 
     Alternatively, a substrate of the inkjet head may be configured to include a temperature detection element (which is an example of a determination signal output part). After the heater is driven by applying a first application voltage to the inkjet head so that the ink droplet is ejected, and thereafter, the heather is driven to apply a second application voltage to the inkjet head so that the ink droplet is not ejected. The temperature detection element may detect a variation of the detected temperature from the application of the second voltage to an elapse of a particular time period, and output the determination signal based on the change of the temperature detected by the temperature detection element. 
     In the above example, each nozzle  10  is examined to determine whether an ink droplet is ejected from the nozzle, and the nozzle from which the ink droplet is not ejected is determined to be the ejection-defective nozzle. Aspects of the present disclosures do not need to be limited to such a configuration. For example, a configuration to detect an ink ejection speed or an ink ejection direction of the ink droplet ejected from the nozzle may be provided, and the nozzle of which the ink ejection speed or the ink ejection direction is abnormal may be determined to be the ejection-defective nozzle. 
     An example employing the printer provided with a so-called serial head, which is configured to move in the scanning direction with the carriage, is described in the description above. Aspects of the present disclosures do not need to be limited to such a configuration. That is, another example may employ a printer provided with a so-called line head, which extends over an entire length, in the scanning direction, of the recording sheet P. 
     In the above description, aspects of the present disclosures are applied to the printer, which is configured to record on the recording sheet P by causing the nozzles to eject the ink droplets. However, aspects of the present disclosures do not need to be limited to such a configuration, but can be applied to a printer configured to record an image on a recording medium other than the recording sheet P. Examples of such recording media include, for example, a T-shirt, a sheet for outdoor advertisement, a case for a portable terminal (e.g., a smartphone), cardboard, a resin member and the like. Further, aspects of the present disclosure may also be applied to a liquid ejection device configured to eject a liquid other than the ink (e.g., liquefied resin, liquefied metal or the like).