Patent Publication Number: US-2023142135-A1

Title: Jet parameter generation system, method of generating jet parameter, and non-transitory computer-readable storage medium storing program of generating jet parameter

Description:
RELATED APPLICATIONS 
     This application claims priority to Japanese Patent Application No. 2021-183749, filed on Nov. 10, 2021, the entire content of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates to a jet parameter generation system, a method of generating a jet parameter, and a non-transitory computer-readable storage medium storing a program of generating a jet parameter. 
     2. Description of the Related Art 
     Liquid jet recording devices equipped with liquid jet heads are used in a variety of fields, and a variety of types of liquid jet heads have been developed (see, e.g., JP-A-2016-203393). 
     In such liquid jet heads, it is required to enhance convenience of the user. 
     It is desirable to provide a jet parameter generation system, a method of generating a jet parameter, and a program of generating a jet parameter each capable of enhancing the convenience of the user. 
     SUMMARY OF THE INVENTION 
     A jet parameter generation system according to an embodiment of the present disclosure is a system configured to generate a predetermined jet parameter to be used when generating a drive signal which is applied to a jet section configured to jet liquid, and which has a single pulse or a plurality of pulses, the system including a data acquisition section configured to obtain a selection instruction signal input from an outside and a predetermined input parameter as input data, and a parameter generation section configured to generate the predetermined jet parameter based on the selection instruction signal and the predetermined input parameter using a predetermined analytical method taking the predetermined input parameter as an explanatory variable and taking the predetermined jet parameter as an objective variable. The parameter generation section determines which one of a first standard and a second standard is to be selected based on the selection instruction signal representing which one of the first standard and the second standard is to be selected, a voltage value representing a crest value of the pulse in the drive signal being set to a voltage value with which a drop volume of the liquid to be a reference is obtained based on the first standard, and being set to a voltage value with which an ejection speed of the liquid to be a reference is obtained based on the second standard, selects a first explanatory variable group included in the predetermined input parameter as the explanatory variable when determining that the first standard is to be selected, while selecting a second explanatory variable group included in the predetermine input parameter as the explanatory variable when determining that the second standard is to be selected, and uses the predetermined analytical method using just selected one of the first explanatory variable group and the second explanatory variable group to thereby generate the predetermined jet parameter. 
     A method of generating a jet parameter according to an embodiment of the present disclosure is a method of generating a predetermined jet parameter to be used when generating a drive signal which is applied to a jet section configured to jet liquid, and which has a single pulse or a plurality of pulses, the method including obtaining a selection instruction signal input from an outside and a predetermined input parameter as input data, and generating the predetermined jet parameter based on the selection instruction signal and the predetermined input parameter using a predetermined analytical method taking the predetermined input parameter as an explanatory variable and taking the predetermined jet parameter as an objective variable. When generating the predetermined jet parameter, which one of a first standard and a second standard is to be selected is determined based on the selection instruction signal representing which one of the first standard and the second standard is to be selected, a voltage value representing a crest value of the pulse in the drive signal being set to a voltage value with which a drop volume of the liquid to be a reference is obtained based on the first standard, and being set to a voltage value with which an ejection speed of the liquid to be a reference is obtained based on the second standard, a first explanatory variable group included in the predetermined input parameter is selected as the explanatory variable when determining that the first standard is to be selected, while a second explanatory variable group included in the predetermine input parameter is selected as the explanatory variable when determining that the second standard is to be selected, and the predetermined analytical method using just selected one of the first explanatory variable group and the second explanatory variable group is used to thereby generate the predetermined jet parameter. 
     A non-transitory computer-readable storage medium storing a program of generating a jet parameter is a non-transitory computer-readable storage medium storing a program of generating a predetermined jet parameter to be used when generating a drive signal which is applied to a jet section configured to jet liquid, and which has a single pulse or a plurality of pulses, the program making a computer execute processing including obtaining a selection instruction signal input from an outside and a predetermined input parameter as input data, and generating the predetermined jet parameter based on the selection instruction signal and the predetermined input parameter using a predetermined analytical method taking the predetermined input parameter as an explanatory variable and taking the predetermined jet parameter as an objective variable. When generating the predetermined jet parameter, which one of a first standard and a second standard is to be selected is determined based on the selection instruction signal representing which one of the first standard and the second standard is to be selected, a voltage value representing a crest value of the pulse in the drive signal being set to a voltage value with which a drop volume of the liquid to be a reference is obtained based on the first standard, and being set to a voltage value with which an ejection speed of the liquid to be a reference is obtained based on the second standard, a first explanatory variable group included in the predetermined input parameter is selected as the explanatory variable when determining that the first standard is to be selected, while a second explanatory variable group included in the predetermine input parameter is selected as the explanatory variable when determining that the second standard is to be selected, and the predetermined analytical method using just selected one of the first explanatory variable group and the second explanatory variable group is used to thereby generate the predetermined jet parameter. 
     According to the jet parameter generation system, the method of generating the jet parameter, and the non-transitory computer-readable storage medium storing the program of generating the jet parameter related to the embodiment of the present disclosure, it becomes possible to enhance the convenience of the user. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic perspective view showing a schematic configuration example of a liquid jet recording device according to an embodiment of the present disclosure. 
         FIG.  2    is a schematic diagram showing a schematic configuration example of a liquid jet head shown in  FIG.  1   . 
         FIG.  3    is a functional block diagram showing a configuration example of a jet parameter generation system according to the embodiment. 
         FIG.  4    is a physical block diagram showing a configuration example of an information processing device shown in  FIG.  3   . 
         FIG.  5    is a block diagram showing a detailed configuration example of a machine learning model shown in  FIG.  3    and  FIG.  4   . 
         FIG.  6 A ,  FIG.  6 B  and  FIG.  6 C  are each a timing chart schematically showing a configuration example of a drive signal. 
         FIG.  7    is a diagram showing an example of predetermined input parameters related to the embodiment. 
         FIG.  8    is a diagram showing an example of an importance analysis result of input parameters related to Comparative Example 1. 
         FIG.  9 A  is a diagram showing an example of a correspondence relationship between an SVM predicted value and a measured value related to Comparative Example 1. 
         FIG.  9 B  is a diagram showing an example of a correspondence relationship between an RF predicted value and a measured value related to Comparative Example 1. 
         FIG.  10    is a flowchart showing an example of jet parameter generation processing related to the embodiment. 
         FIG.  11 A  is a diagram showing an example of an importance analysis result of a first explanatory variable group related to the embodiment. 
         FIG.  11 B  is a diagram showing an example of an importance analysis result of a second explanatory variable group related to the embodiment. 
         FIG.  12 A  is a diagram showing an example of a correspondence relationship between the SVM predicted value and the measured value when using only the first explanatory variable group shown in  FIG.  11 A . 
         FIG.  12 B  is a diagram showing an example of a correspondence relationship between the RF predicted value and the measured value when using only the first explanatory variable group shown in  FIG.  11 A . 
         FIG.  13 A  is a diagram showing an example of a correspondence relationship between the SVM predicted value and the measured value when using only the second explanatory variable group shown in  FIG.  11 B . 
         FIG.  13 B  is a diagram showing an example of a correspondence relationship between the RF predicted value and the measured value when using only the second explanatory variable group shown in  FIG.  11 B . 
         FIG.  14    is a block diagram showing a configuration example of a machine learning model related to Modified Example 1. 
         FIG.  15    is a block diagram showing a schematic configuration example of a liquid jet recording device according to Comparative Example 2. 
         FIG.  16    is a diagram showing an example of viscosity information related to Comparative Example 2. 
         FIG.  17    is a diagram showing an example of a variety of characteristic curves related to Comparative Example 2. 
         FIG.  18    is a flowchart showing an example of conversion processing related to Modified Example 1. 
         FIG.  19    is a diagram showing an example of a variety of characteristic curves related to Modified Example 1. 
         FIG.  20    is a diagram showing an example of predetermined input parameters related to Modified Example 1. 
         FIG.  21    is a flowchart showing characteristic table generation processing and so on related to Modified Example 1. 
         FIG.  22    is a diagram showing an example of an importance analysis result of input parameters related to Comparative Example 3. 
         FIG.  23 A  is a diagram showing an example of an importance analysis result of a first explanatory variable group related to Modified Example 1. 
         FIG.  23 B  is a diagram showing an example of an importance analysis result of a second explanatory variable group related to Modified Example 1. 
         FIG.  24 A  is a diagram showing an example of a correspondence relationship between the SVM predicted value and the measured value when using only the first explanatory variable group shown in  FIG.  23 A . 
         FIG.  24 B  is a diagram showing an example of a correspondence relationship between the RF predicted value and the measured value when using only the first explanatory variable group shown in  FIG.  23 A . 
         FIG.  25 A  is a diagram showing an example of a correspondence relationship between the SVM predicted value and the measured value when using only the second explanatory variable group shown in  FIG.  23 B . 
         FIG.  25 B  is a diagram showing an example of a correspondence relationship between the RF predicted value and the measured value when using only the second explanatory variable group shown in  FIG.  23 B . 
         FIG.  26    is a block diagram showing a configuration example of a machine learning model related to Modified Example 2. 
         FIG.  27    is a diagram showing an example of predetermined input parameters related to Modified Example 2. 
         FIG.  28    is a diagram showing an example of an importance analysis result of input parameters related to Comparative Example 4. 
         FIG.  29 A  is a diagram showing an example of an importance analysis result of a first explanatory variable group related to Modified Example 2. 
         FIG.  29 B  is a diagram showing an example of an importance analysis result of a second explanatory variable group related to Modified Example 2. 
         FIG.  30 A  is a diagram showing an example of a correspondence relationship between the SVM predicted value and the measured value when using only the first explanatory variable group shown in  FIG.  29 A . 
         FIG.  30 B  is a diagram showing an example of a correspondence relationship between the RF predicted value and the measured value when using only the first explanatory variable group shown in  FIG.  29 A . 
         FIG.  31 A  is a diagram showing an example of a correspondence relationship between the SVM predicted value and the measured value when using only the second explanatory variable group shown in  FIG.  29 B . 
         FIG.  31 B  is a diagram showing an example of a correspondence relationship between the RF predicted value and the measured value when using only the second explanatory variable group shown in  FIG.  29 B . 
         FIG.  32    is a block diagram showing a configuration example of a jet parameter generation system according to Modified Example 3. 
         FIG.  33    is a block diagram showing a configuration example of a jet parameter generation system according to Modified Example 4. 
         FIG.  34    is a block diagram showing a configuration example of a jet parameter generation system according to Modified Example 5. 
         FIG.  35    is a block diagram showing a configuration example of an information processor related to Modified Example 6. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of the present disclosure will hereinafter be described in detail with reference to the drawings. It should be noted that the description will be presented in the following order.
     1. Embodiment (an example in which an information processor is disposed in an information processing device located outside a liquid jet recording device)   2. Modified Examples   

     Modified Example 1 (an example when a predetermined jet parameter is a conversion coefficient) 
     Modified Example 2 (an example when a predetermined jet parameter is a voltage shift amount) 
     Modified Example 3 (an example in which an information processor is disposed in a server located outside a liquid jet recording device) 
     Modified Example 4 (an example in which an information processor is disposed inside a liquid jet head in a liquid jet recording device) 
     Modified Example 5 (an example in which an information processor is disposed outside a liquid jet head in a liquid jet recording device) 
     Modified Example 6 (an example in which a signal generation section is further disposed in an information processor)
     3. Other Modified Examples   

     1. EMBODIMENT 
     [A. Overall Configuration of Printer  1 ] 
       FIG.  1    is a perspective view schematically showing a schematic configuration example of a printer  1  as a liquid jet recording device according to an embodiment of the present disclosure. The printer  1  is an inkjet printer for performing recording (printing) of images, characters, and the like on recording paper P as a recording target medium using ink  9  described later. 
     As shown in  FIG.  1   , the printer  1  is provided with a pair of carrying mechanisms  2   a ,  2   b , ink tanks  3 , ink supply tubes  30 , inkjet heads  4 , and a scanning mechanism  6 . These members are housed in a chassis  10  having a predetermined shape. It should be noted that a scale size of each of the members is accordingly altered so that the member is shown in a recognizable size in the drawings used in the description of the present specification. 
     Here, the printer  1  corresponds to a specific example of the “liquid jet recording device” in the present disclosure, and the inkjet heads  4  (inkjet heads  4 Y,  4 M,  4 C, and  4 K described later) each correspond to a specific example of a “liquid jet head” in the present disclosure. Further, the ink  9  corresponds to a specific example of a “liquid” in the present disclosure. 
     As shown in  FIG.  1   , the carrying mechanisms  2   a ,  2   b  are each a mechanism for carrying the recording paper P along a carrying direction d (an X-axis direction). These carrying mechanisms  2   a ,  2   b  each have a grit roller  21 , a pinch roller  22 , and a drive mechanism (not shown). This drive mechanism is a mechanism for rotating (rotating in a Z-X plane) the grit roller  21  around an axis, and is constituted by, for example, a motor. 
     (Ink Tanks  3 ) 
     The ink tanks  3  are each a tank for containing the ink  9  inside. As the ink tanks  3 , there are disposed four types of tanks which individually contain the ink  9  of four colors of yellow (Y), magenta (M), cyan (C), and black (K) in this example as shown in  FIG.  1   . Specifically, there are disposed the ink tank  3 Y for containing the ink  9  having a yellow color, the ink tank  3 M for containing the ink  9  having a magenta color, the ink tank  3 C for containing the ink  9  having a cyan color, and the ink tank  3 K for containing the ink  9  having a black color. These ink tanks  3 Y,  3 M,  3 C, and  3 K are arranged side by side along the X-axis direction inside the chassis  10 . 
     It should be noted that the ink tanks  3 Y,  3 M,  3 C, and  3 K have the same configuration except the color of the ink  9  contained, and are therefore collectively referred to as ink tanks  3  in the following description. 
     (Inkjet Heads  4 ) 
     The inkjet heads  4  are each a head for jetting (ejecting) the ink  9  shaped like a droplet from a plurality of nozzles (nozzle holes Hn) described later to the recording paper P to thereby perform recording (printing) of images, characters, and so on. As the inkjet heads  4 , there are also disposed four types of heads for individually jetting the four colors of ink  9  respectively contained in the ink tanks  3 Y,  3 M,  3 C, and  3 K described above in this example as shown in  FIG.  1   . Specifically, there are disposed the inkjet head  4 Y for jetting the ink  9  having a yellow color, the inkjet head  4 M for jetting the ink  9  having a magenta color, the inkjet head  4 C for jetting the ink  9  having a cyan color, and the inkjet head  4 K for jetting the ink  9  having a black color. These inkjet heads  4 Y,  4 M,  4 C and  4 K are arranged side by side along the Y-axis direction inside the chassis  10 . 
     It should be noted that the inkjet heads  4 Y,  4 M,  4 C and  4 K have the same configuration except the color of the ink  9  used therein, and are therefore collectively referred to as inkjet heads  4  in the following description. Further, the detailed configuration example of the inkjet heads  4  will be described later ( FIG.  2   ). 
     The ink supply tubes  30  are each a tube through which the ink  9  is supplied from the inside of the ink tank  3  toward the inside of the inkjet head  4 . The ink supply tubes  30  are each formed of, for example, a flexible hose having such flexibility as to be able to follow the action of the scanning mechanism  6  described below. 
     (Scanning Mechanism  6 ) 
     The scanning mechanism  6  is a mechanism for making the inkjet heads  4  perform a scanning operation along the width direction of the recording paper P (the Y-axis direction). As shown in  FIG.  1   , the scanning mechanism  6  has a pair of guide rails  61   a ,  61   b  disposed so as to extend along the Y-axis direction, a carriage  62  movably supported by these guide rails  61   a ,  61   b , and a drive mechanism  63  for moving the carriage  62  along the Y-axis direction. 
     The drive mechanism  63  has a pair of pulleys  631   a ,  631   b  disposed between the guide rails  61   a ,  61   b , an endless belt  632  wound between these pulleys  631   a ,  631   b , and a drive motor  633  for rotationally driving the pulley  631   a . Further, on the carriage  62 , there are arranged the four types of inkjet heads  4 Y,  4 M,  4 C and  4 K described above side by side along the Y-axis direction. 
     It should be noted that it is arranged that such a scanning mechanism  6  and the carrying mechanisms  2   a ,  2   b  described above constitute a moving mechanism for moving the inkjet heads  4  and the recording paper P relatively to each other. 
     [B. Detailed Configuration of Inkjet Heads  4 ] 
     Then, the detailed configuration example of the inkjet heads  4  will be described with reference to  FIG.  2   . 
       FIG.  2    is a diagram schematically showing the schematic configuration example of each of the inkjet heads  4 . 
     As shown in  FIG.  2   , the inkjet head  4  has a nozzle plate  41 , an actuator plate  42 , and a driver  49 . 
     It should be noted that the nozzle plate  41  and the actuator plate  42  correspond to a specific example of a “jet section” in the present disclosure. 
     (Nozzle Plate  41 ) 
     The nozzle plate  41  is a plate formed of a film material such as polyimide, or a metal material, and has the plurality of nozzle holes Hn for jetting the ink  9  as shown in  FIG.  2    (see the dotted arrows in  FIG.  2   ). These nozzle holes Hn are formed side by side in alignment (along the X-axis direction in this example) at predetermined intervals. 
     (Actuator Plate  42 ) 
     The actuator plate  42  is a plate formed of a piezoelectric material such as PZT (lead zirconate titanate). The actuator plate  42  is provided with a plurality of channels (not shown). These channels are each a part functioning as a pressure chamber for applying pressure to the ink  9 , and are arranged side by side so as to be parallel to each other at predetermined intervals. Each of the channels is partitioned with drive walls (not shown) formed of a piezoelectric body, and forms a groove part having a recessed shape in a cross-sectional view. 
     In such channels, there exist ejection channels for ejecting the ink  9 , and dummy channels (non-ejection channels) which do not eject the ink  9 . In other words, it is configured that the ejection channels are filled with the ink  9  on the one hand, but the dummy channels are not filled with the ink  9  on the other hand. Further, it is configured that each of the ejection channels is communicated with the nozzle hole Hn in the nozzle plate  41  on the one hand, but each of the dummy channels is not communicated with the nozzle hole Hn on the other hand. The ejection channels and the dummy channels are alternately arranged side by side along a predetermined direction. 
     On the inner side surfaces opposed to each other in the drive wall described above, there are respectively disposed drive electrodes (not shown). As the drive electrodes, there exist common electrodes disposed on the inner side surfaces facing the ejection channels, and active electrodes (individual electrodes) disposed on the inner side surfaces facing the dummy channels. These drive electrodes and the drive circuit in a drive board (not shown) are electrically coupled to each other via a plurality of extraction electrodes provided to a flexible board (not shown). Thus, it is configured that a drive voltage Vd (a drive signal Sd) is applied to each of the drive electrodes from the drive circuit including the driver  49  via the flexible board. 
     (Driver  49 ) 
     The driver  49  is a device which applies the drive voltages Vd (the drive signal Sd) described above to the actuator plate  42  to expand or contract the ejection channels described above to thereby jet (make the actuator plate  42  perform the jetting operation of) the ink  9  from the respective nozzle holes Hn (see  FIG.  2   ). Specifically, the driver  49  is configured to make the actuator plate  42  perform such a jet operation using the drive signal Sd generated in a signal generation section  48  described later. 
     [C. Overall Configuration of Jet Parameter Generation System  5 ] 
     Then, an overall configuration example of a jet parameter generation system  5  (a characteristic table generation system) configured including the printer  1  having the inkjet heads  4  described above will be described with reference to  FIG.  3    through  FIG.  6 C . 
       FIG.  3    is a block diagram (a functional block diagram) showing the configuration example of the jet parameter generation system  5  according to the present embodiment, and  FIG.  4    is a block diagram (a physical block diagram) showing a configuration example of the information processing device  7  (described later) shown in  FIG.  3   . Further,  FIG.  5    is a block diagram showing a detailed configuration example of a machine learning model  74  shown in  FIG.  3    and  FIG.  4   . 
     It should be noted that a jet parameter generation method (a characteristic table generation method) according to the present embodiment is embodied in the jet parameter generation system  5  (a characteristic table generation system) according to the present embodiment, and therefore will also be described. This point also applies to modified examples (Modified Examples  1  through  6 ) described later. 
     The jet parameter generation system  5  is a system for generating a predetermined jet parameter Prj used when generating the drive signal Sd described above. Further, in the jet parameter generation system  5  (the characteristic table generation system), it is configured that a predetermined predictive voltage characteristic table TPvp is generated based on the jet parameter Prj generated in such a manner (see  FIG.  3   ). As shown in  FIG.  3   , the jet parameter generation system  5  is provided with the printer  1  having the inkjet heads  4  described above, and the information processing device  7 . Further, the printer  1  and the information processing device  7  are connected to each other via a network  50 . 
     It should be noted that such a network  50  is, for example, a network which performs communication using a communications protocol (TCP/IP) normally used in the Internet. The network  50  can be, for example, a secure network which performs communication using a communications protocol unique to the network. Further, the network  50  is, for example, the Internet, an intranet, or a local area network. The connection between such a network  50 , and the printer  1  and the information processing device  7  can be achieved by, for example, a wired LAN (Local Area Network) such as Ethernet (a registered trademark), a wireless LAN such as Wi-Fi (a registered trademark), or a mobile telephone line. 
     (Information Processing Device  7 ) 
     The information processing device  7  is a device located outside the printer  1 , and is formed of, for example, a PC (Personal Computer). As shown in  FIG.  3    (the functional block diagram), the information processing device  7  has an input section  71 , a display section  72 , an information processor  73 , and the machine learning model  74 . 
     It should be noted that such an information processing device  7  corresponds to a specific example of an “external device” in the present disclosure. 
     The input section  71  is a section which receives an instruction from the outside (e.g., a user), and then outputs the instruction thus received to the information processor  73 . Such an input section  71  is formed of, for example, a keyboard and a mouse. Further, it is possible for the input section  71  to be formed of, for example, a touch panel disposed on (a display surface of) the display section  72  in the information processing device  7 . 
     The display section  72  is a section which displays an image based on a video signal output from the information processor  73 . Such a display section  72  is configured using a display of a variety of types (e.g., a liquid crystal display, a CRT (Cathode Ray Tube) display, or an organic EL (Electro Luminescence) display). 
     The information processor  73  is a section for performing a variety of types of information processing and so on, and has a data acquisition section  731 , a parameter generation section  732 , and a table generation section  733  as shown in  FIG.  3   . Further, as shown in  FIG.  4    (the physical block diagram), such an information processor  73  is configured using a controller  75 , a storage  76 , and a network IF (Interface)  77 . It should be noted that in the example shown in  FIG.  4   , the input section  71 , the display section  72 , the controller  75 , the storage  76 , and the network IF  77  are coupled to each other via a bus  70 . 
     As shown in  FIG.  3   , the data acquisition section  731  is a section which obtains the following data (input data) via the input section  71 , the network  50 , and so on described above. Specifically, the data acquisition section  731  is configured to obtain a predetermined measured viscosity characteristic table TMvi, a predetermined selection instruction signal Ss input from the outside, and predetermined input parameters Prin described later as the input data. 
     As shown in  FIG.  3   , the parameter generation section  732  is a section which generates the predetermined jet parameter Prj described above by using a predetermined analytical method based on the selection instruction signal Ss and the input parameters Prin obtained in the data acquisition section  731 . The predetermined analytical method means an analytical method taking the input parameters Prin described above as explanatory variables, and at the same time, taking the jet parameter Prj described above as an objective variable. Further, as shown in  FIG.  3    and  FIG.  4   , in the example of the present embodiment, the parameter generation section  732  is configured to generate the jet parameter Prj based on the input parameters Prin utilizing an analytical method using the machine learning model  74  hereinafter described. 
     As described above, such a machine learning model  74  is a predictive model obtained by performing the mechanical learning taking the input parameters Prin as the explanatory variables and taking the jet parameter Prj as the objective variable. Further, as shown in  FIG.  5   , the machine learning model  74  is configured to generate (predict) the jet parameter Prj (the objective variable) based on a learning result and then output the jet parameter Prj thus generated when the input parameters Prin (the explanatory variables) are input. 
     Here, as shown in, for example,  FIG.  5   , in the present embodiment, there is described mainly when the jet parameter Prj is generated so as to include at least a voltage sensitivity Vr described later as an example. In other words, the voltage sensitivity Vr corresponds to a specific example of a “predetermined jet parameter” in the present disclosure. 
     It should be noted that as the analytical method (a prediction method) using the machine learning model  74  described above, there can be cited, for example, a support vector machine (SVM), a random forest (RF), and a multiple regression analysis. 
     As shown in  FIG.  3   , the table generation section  733  is a section which performs a predetermined conversion process using at least one of the measured viscosity characteristic table TMvi obtained by the data acquisition section  731  and the jet parameters Prj generated by the parameter generation section  732  to thereby generate the predictive voltage characteristic table TPvp. The predictive voltage characteristic table TPvp generated in such a manner is configured to be supplied to a signal generation section  48  described later in the inkjet head  4  in the printer  1  via the network  50 . 
     It should be noted that the details of the predetermined conversion process described above, the measured viscosity characteristic table TMvi, and the predictive voltage characteristic table TPvp will be described in Modified Example 1 described later. Further, the details of processing in such an information processor  73  (the data acquisition section  731 , the parameter generation section  732 , and the table generation section  733 ) will also be described later. 
     The controller  75  shown in  FIG.  4    is a section configured including a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and so on to execute, for example, a variety of programs stored in the storage  76 . Specifically, as shown in, for example,  FIG.  4   , the controller  75  is configured to execute a program  730  stored in the storage  76 . The program  730  is a program for executing the processing in the information processor  73  (the data acquisition section  731 , the parameter generation section  732 , and the table generation section  733 ) described above. Specifically, the program  730  is a program for making a computer (the controller  75 ) execute the functions in the information processor  73  (the data acquisition section  731 , the parameter generation section  732 , and the table generation section  733 ). 
     The storage  76  is a section for storing a variety of programs to be executed by the controller  75  and a variety of types of data. As shown in  FIG.  4   , the storage  76  stores the program  730  described above as an example of such a variety of programs, and at the same time, stores the machine learning model  74  described above as an example of such a variety of types of data. Such a storage  76  is configured using, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), and an auxiliary storage device (a hard disk drive or the like). 
     As shown in  FIG.  4   , the network IF  77  is a communication interface for performing communication with the printer  1  via the network  50 . 
     (Signal Generation Section  48 ) 
     Here, in the example shown in  FIG.  3   , the inkjet heads  4  each have the signal generation section  48  in addition to the nozzle plate  41 , the actuator plate  42 , and the driver  49  described above. The signal generation section  48  is a section for generating the drive signal Sd having one pulse or a plurality of pulses (having a pulse width Wp and a voltage value Vp representing a crest value) using the predictive voltage characteristic table TPvp generated by the table generation section  733  in the information processing device  7  in such a manner as described above. 
     Here,  FIG.  6 A  through  FIG.  6 C  are each a timing chart schematically showing a configuration example of such a drive signal Sd. It should be noted that in  FIG.  6 A  through  FIG.  6 C , the horizontal axis represents time t, and the vertical axis represents a drive voltage Vd (a positive voltage in this example) in the drive signal Sd, respectively. 
     First, the drive signal Sd shown in  FIG.  6 A  has a single pulse (a pulse Pa) and corresponds to an example of a case of a so-called “one drop.” The pulse Pa represents an ON period disposed between a rising timing and a falling timing, and has a pulse width Wpal and a voltage value Vp 1  as an example of the pulse width Wp and the voltage value Vp described above. 
     In contrast, the drive signal Sd shown in  FIG.  6 B  has the following two pulses (pulses Pa, Pb) as the pulses to which a so-called “multi-pulse method” is applied (an example of a case of a so-called “two drops”). That is, as such pulses (the ON periods), there are disposed the two pulses, namely the pulses Pa, Pb. It should be noted that an OFF period (“OFF 1 ”) is disposed between these two pulses Pa, Pb. Further, as an example of the pulse width Wp and the voltage value Vp described above, the pulse Pa has a pulse width Wpa 2  and a voltage value Vp 2 , and the pulse Pb has a pulse width Wpb 2  and the voltage value Vp 2 . 
     Similarly, the drive signal Sd shown in  FIG.  6 C  has the following three pulses (pulses Pa, Pb, and Pc) as the pulses to which the “multi-pulse method” described above is applied (an example of a case of a so-called “three drops”). That is, as such pulses (the ON periods), there are disposed the three pulses, namely the pulses Pa, Pb, and Pc. It should be noted that an OFF period (“OFF 1 ”) is disposed between the pulses Pa, Pb, and at the same time, an OFF period (“OFF 2 ”) is disposed between the pulses Pb, Pc. Further, as an example of the pulse width Wp and the voltage value Vp described above, the pulse Pa has a pulse width Wpa 3  and a voltage value Vp 3 , the pulse Pb has a pulse width Wpb 3  and the voltage value Vp 3 , and the pulse Pc has a pulse width Wpc 3  and the voltage value Vp 3 . 
     It should be noted that each of these pulses Pa, Pb, and Pc in the drive signal Sd forms a positive pulse which expands the ejection channel described above in a period of a high (High) state, and contracts the ejection channel in a period of a low (Low) state. 
     Here, the signal generation section  48  sets each of the pulse width Wp and the voltage value Vp in such pulses (the pulses Pa, Pb, and Pc) to generate the drive signal Sd using the pulse width Wp and the voltage value Vp thus set. Specifically, the signal generation section  48  is configured to obtain the voltage value Vp of the pulse using the predictive voltage characteristic table TPvp described above, and at the same time, generate the drive signal Sd using the pulse having the voltage value Vp thus obtained. 
     It should be noted that the voltage value Vp described above corresponds to a specific example of the “crest value” in the present disclosure. Further, the “pulse” described above is in a concept including not only such rectangular waves as shown in  FIG.  6 A  through  FIG.  6 C , but also waveforms such as a trapezoidal wave, a triangular wave, or a stepped wave, which applies to the following. 
     s[Operations and Functions/Advantages] 
     (A. Basic Operation of Printer  1 ) 
     In the printer  1 , a recording operation (a printing operation) of images, characters, and so on to the recording paper P is performed in the following manner. It should be noted that as an initial state, it is assumed that the four types of ink tanks  3  ( 3 Y,  3 M,  3 C, and  3 K) shown in  FIG.  1    are sufficiently filled with the ink  9  of the corresponding colors (the four colors), respectively. Further, there is achieved the state in which the inkjet heads  4  are filled with the ink  9  in the ink tanks  3  via the ink supply tubes  30 , respectively. 
     In such an initial state, when making the printer  1  operate, the grit rollers  21  in the carrying mechanisms  2   a ,  2   b  each rotate to thereby carry the recording paper P along the carrying direction d (the X-axis direction) between the grit rollers  21  and the pinch rollers  22 . Further, at the same time as such a carrying operation, the drive motor  633  in the drive mechanism  63  rotates each of the pulleys  631   a ,  631   b  to thereby operate the endless belt  632 . Thus, the carriage  62  reciprocates along the width direction (the Y-axis direction) of the recording paper P while being guided by the guide rails  61   a ,  61   b . Then, on this occasion, the four colors of ink  9  are appropriately ejected on the recording paper P by the respective inkjet heads  4  ( 4 Y,  4 M,  4 C, and  4 K) to thereby perform the recording operation of images, characters, and so on to the recording paper P. 
     (B. Detailed Operation in Inkjet Head  4 ) 
     Then, the detailed operation (a jet operation of the ink  9 ) in the inkjet head  4  will be described. Specifically, in this inkjet head  4 , the jet operation of the ink  9  using a shear mode is performed in the following manner. 
     First, the driver  49  applies the drive voltages Vd (the drive signal Sd) to the drive electrodes (the common electrodes and the active electrodes) described above in the actuator plate  42  (see  FIG.  2    and  FIG.  3   ). Specifically, the driver  49  applies the drive voltage Vd to each of the drive electrodes disposed on the pair of drive walls partitioning the ejection channel described above. Thus, the pair of drive walls each deform so as to protrude toward the dummy channel adjacent to the ejection channel. 
     On this occasion, it results in that the drive wall makes a flexion deformation to have a V shape centering on the intermediate position in the depth direction in the drive wall. Further, due to such a flexion deformation of the drive wall, the ejection channel deforms as if the ejection channel bulges. As described above, due to the flexion deformation caused by a piezoelectric thickness-shear effect in the pair of drive walls, the volume of the ejection channel increases. Further, by the volume of the ejection channel increasing, the ink  9  is induced into the ejection channel as a result. 
     Subsequently, the ink  9  induced into the ejection channel in such a manner turns to a pressure wave to propagate to the inside of the ejection channel. Then, the drive voltage Vd to be applied to the drive electrodes becomes 0 (zero) V at the timing at which the pressure wave has reached the nozzle hole Hn of the nozzle plate  41  (or timing in the vicinity of that timing). Thus, the drive walls are restored from the state of the flexion deformation described above, and as a result, the volume of the ejection channel having once increased is restored again. 
     In such a manner, the pressure in the ejection channel increases in the process that the volume of the ejection channel is restored, and thus, the ink  9  in the ejection channel is pressurized. As a result, the ink  9  having a droplet shape is ejected (see  FIG.  2    and  FIG.  3   ) toward the outside (toward the recording paper P) through the nozzle hole Hn. The jet operation (the ejection operation) of the ink  9  in the inkjet head  4  is performed in such a manner, and as a result, the recording operation (the printing operation) of images, characters, and so on to the recording paper P is performed. 
     (C. Operation of Generating Jet Parameters) 
     Then, an operation of generating (generation processing of) the jet parameters Prj (in the case of the voltage sensitivity Vr described above) in the jet parameter generation system  5  will be described in detail with reference to  FIG.  7    through  FIG.  13 B  in addition to  FIG.  1    through  FIG.  6 C  while comparing to a comparative example ( FIG.  8   ,  FIG.  9 A , and  FIG.  9 B ). 
     Incidentally, the voltage sensitivity Vr (the voltage sensitivity Vr when performing ejection) means a value (unit: [pl/V] or [m/s/V]) corresponding to a variation per unit voltage in the drop volume (DV) or the ejection speed of the ink  9  when the ink  9  is jetted at a reference temperature Tr. 
     (C-1. Regarding Input Parameters Prin) 
     First, as the predetermined input parameters Prin described above, there can be cited those listed in (a) through ( 1 ) below as an example as shown in  FIG.  7   .  FIG.  7    is a diagram showing an example of the input parameters Prin related to the present embodiment. It should be noted that in  FIG.  7   , the values of the input parameters Prin are shown with respect to six samples (“sample  1 ” through “sample  6 ”). 
     (a) the number of drops (the number of pulses)—corresponding to the number of pulses included in a unit period in the drive signal Sd described above with reference to  FIG.  6 A  through  FIG.  6 C   
     (b) presence or absence of the common drive (“0”: absence, “1”: presence, “2”: a special value)—a so-called common drive (a drive method of setting the pulse of the drive signal Sd so as to include a change in which the volume of the ejection channel is contracted from a standard value when ejecting the ink  9 ) 
     (c) a head type—a symbol or the like representing a type of the inkjet heads  4   
     (d) an ink type—a type of the ink  9  classified in accordance with a chief solvent of the ink  9  (“Oil”: the ink  9  with an oil solvent, “sol”: the ink  9  with an organic solvent, “UV”: UV (ultraviolet) curable ink, and “WB”: the Water Base (with water as the chief solvent) ink  9 ) 
     (e) DV standard or Vj standard—a parameter representing which one of a standard (“DV standard”) for setting the voltage value Vp with which the drop volume of the ink  9  to be the standard can be obtained when the ink  9  is jetted and a standard (“Vj standard”) for setting the voltage value Vp with which the ejection speed to be the standard can be obtained is selected 
     (f) a head rank value—a value (unit: [V]) which is inherent in the inkjet head  4 , and corresponds to the voltage value Vp with which a predetermined ejection speed is achieved when a predetermined test liquid is jetted from the inkjet head  4   
     (g) a viscosity value at the reference temperature Tr—a viscosity value (unit: [mPa]) of the ink  9  at the reference temperature Tr when using the ink  9  while heated 
     (h) a surface tension value of the ink  9  (unit: [mN/m]) 
     (i) a specific gravity value of the ink  9  (or a physical property value (e.g., a density of the ink  9  or a sound speed in the ink  9 ) which can be obtained using the specific gravity value of the ink  9 ) 
     (j) a target value of the DV (drop volume) or the Vj (the ejection speed) of the ink  9   
     (k) voltage shift amount ΔVp (a parameter used in the predetermined conversion processing described above; described later in detail in Modified Example 1) 
     Incidentally, the “viscosity of the ink  9 ” mentioned here means static viscosity, which applies to the following. Further, such a viscosity value of the ink  9  is configured to be measured using, for example, a rotary viscometer, a vibratory viscometer, or a viscometer (a viscometer capable of measuring static viscosity) of other measuring methods such as a canalicular type or a falling-ball type. 
     (C-2. Comparative Example 1) 
     Here,  FIG.  8    is a diagram showing an example of an importance analysis result of the input parameters Prin related to Comparative Example 1. Further,  FIG.  9 A  is a diagram showing an example (an example when extracting only the Vj standard described above) of a correspondence relationship between an SVM predicted value and a measured value related to Comparative Example 1. Similarly,  FIG.  9 B  is a diagram showing an example (an example when extracting only the Vj standard described above) of a correspondence relationship between an RF predicted value and a measured value related to Comparative Example 1. Comparative Example 1 corresponds to when using the predetermined analytical method described above in a condition in which both of the DV standard and the Vj standard described above are mixed with each other although the details will be described later. 
     It should be noted that the importance in the importance analysis result shown in  FIG.  8    means an index (a contribution rate) for measuring how much the division of the feature amount thereof makes a contribution to the classification of the target, and is configured to be calculated using a predetermined calculating formula based on so-called Gini impurity. Such a definition of the importance also applies to the following. 
     Further, in the examples shown in  FIG.  9 A  and  FIG.  9 B , the (x,y) coordinate in each of a number of (562) samples is plotted when defining the measured value of the voltage sensitivity Vr as a variable x, and defining the predicted value (the SVM predicted value or the RF predicted value) of the voltage sensitivity Vr as a variable y. Further, in  FIG.  9 A  and  FIG.  9 B , an example of a formula (e.g., a linear function formula identified using a least-square method) representing the tendency of the correlative relationship between these variables x, y is also shown. 
     First, according to an example of the importance analysis result of the input parameters Prin as the explanatory variables shown in  FIG.  8   , the following is the highest in importance (contribution rate) when generating the jet parameter Prj (=the voltage sensitivity Vr) using the machine learning model  74 . That is, the importance is the highest in (j) the target value of DV or Vj out of the input parameters Prin shown in (a) through (l) described above. Further, regarding other input parameters Prin out of such input parameters Prin, the importance is set nearly “0(zero).” 
     Therefore, in Comparative Example 1, the predetermined analytical method described above is used in the condition in which both of the DV standard and the Vj standard are mixed with each other using only (j) the target value of DV or Vj as the input parameter Prin. 
     Then, as shown in, for example,  FIG.  9 A  and  FIG.  9 B , in Comparative Example 1, there can occur the case in which the prediction accuracy when generating the jet parameter Prj degrades. Specifically, in the examples (the examples when extracting only the Vj standard) shown in  FIG.  9 A  and  FIG.  9 B , a gradient in the linear function formula described above is set nearly “0,” and at the same time, an intercept in the linear function formula described above is set significantly greater than “0.” Therefore, in each of the examples shown in  FIG.  9 A  and  FIG.  9 B , the predicted values (the SVM predicted value and the RF predicted value) and the measured value have the following relationship. That is, it results in that it cannot be said that the predicted value and the measured value have a sufficient correlative relationship when performing printing using the predicted value. 
     In such a manner, in Comparative Example 1, as described above, when performing the importance analysis in the condition in which both of the DV standard and the Vj standard are mixed with each other, the importance (a degree of contribution) becomes characteristically high in some cases in a specific input parameter Prin out of the input parameters Prin. Further, in such a case, when using the predetermined analytical method using only the specific input parameter Prin characteristically high in importance as described above, for example, the prediction accuracy of the jet parameter Prj in, for example, the DV standard or the Vj standard degrades in some cases. Specifically, in each of the examples shown in  FIG.  9 A  and  FIG.  9 B , the prediction accuracy of the jet parameter Prj in the Vj standard has degraded. As a result, in Comparative Example 1, there is a possibility that the convenience of the user degrades. 
     (C-3. Processing of Generating Jet Parameters Prj in Present Embodiment) 
     Therefore, in the jet parameter generation system  5  in the present embodiment, it is configured that which one of the DV standard and the Vj standard is to be selected is determined based on the selection instruction signal Ss described above when generating the jet parameters Prj. The processing of generating the jet parameters Prj in the present embodiment will hereinafter be described in detail. 
     It should be noted that the DV standard described above corresponds to a specific example of a “first standard” in the present disclosure. Further, the Vj standard described above corresponds to a specific example of a “second standard” in the present disclosure. 
     Here,  FIG.  10    is a flowchart showing an example of the processing of generating the jet parameters Prj related to the present embodiment. 
     In the processing example shown in  FIG.  10   , first, the parameter generation section  732  determines (steps S 1 , S 2 ) which one of the DV standard and the Vj standard is to be selected based on the selection instruction signal Ss representing which one of the DV standard and the Vj standard described above is selected by the instruction. 
     Here, when, for example, it is determined that the DV standard is selected (Y in the step S 2 ), the parameter generation section  732  selects (step S 31 ) a first explanatory variable group Print (see  FIG.  11 A  described later) included in the input parameters Prin described above as the explanatory variables in the predetermined analytical method (e.g., the machine learning model  74 ). In contrast, when, for example, it is determined that the Vj standard is selected (N in the step S 2 ), the parameter generation section  732  selects (step S 32 ) a second explanatory variable group Prin 2  (see  FIG.  11 B  described later) included in the input parameters Prin as the explanatory variables in the predetermined analytical method. 
     Then, the parameter generation section  732  uses the predetermined analytical method (e.g., the machine learning model  74 ) using one of the first explanatory variable group Print and the second explanatory variable group Prin 2  thus selected alone to thereby generate (step S 4 ) the predetermined jet parameters. 
     This terminates the series of processing shown in  FIG.  10   . 
     Here,  FIG.  11 A  is a diagram showing an example of the importance analysis result in the first explanatory variable group Print described above related to the present embodiment. Further,  FIG.  11 B  is a diagram showing an example of the importance analysis result in the second explanatory variable group Prin 2  described above related to the present embodiment. It should be noted that the examples shown in  FIG.  11 A  and  FIG.  11 B  represent when the jet parameter Prj as the objective variable is the voltage sensitivity Vr as described above. 
     As shown in  FIG.  11 A , as the first explanatory variable group Print related to the present embodiment, there is included, for example, at least one of the following parameters out of the input parameters Prin described above. That is, in the example shown in  FIG.  11 A , there are mainly included (j) the target value of DV, (a) the number of drops, and (k) the voltage shift amount ΔVp. Further, as shown in  FIG.  11 A , the importance (the degree of contribution) becomes relatively higher in this order. 
     Specifically, in the example shown in  FIG.  11 A , in (j) the target value of DV, the importance becomes relatively higher (the highest). Therefore, in the present embodiment, it is desirable that (j) the target value of DV which is the highest in importance is at least included as the first explanatory variable group Print described above. Further, in the present embodiment, as described above, it can be said that it is desirable that at least one of (a) the number of drops and (k) the voltage shift amount ΔVp which are the second highest and the third highest in importance is further included as the first explanatory variable group Print. 
     In contrast, as shown in  FIG.  11 B , as the second explanatory variable group Prin 2  related to the present embodiment, there is included, for example, at least one of the following parameters out of the input parameters Prin described above. Specifically, in the example shown in  FIG.  11 B , there are mainly included (b) presence or absence of common drive, (a) the number of drops, (f) a head rank value, (k) the voltage shift amount ΔVp, (c) a head type, (i) a specific gravity value of the ink  9 , (h) a surface tension value of the ink  9 , (g) a viscosity value at a reference temperature Tr, (j) the target value of Vj, and (d) an ink type. Further, as shown in  FIG.  11 B , the importance (the degree of contribution) becomes relatively higher in this order. 
     Specifically, in the example shown in  FIG.  11 B , in (b) the presence or absence of the common drive and (a) the number of drops, the importance becomes relatively higher (the highest, the second highest), respectively. Therefore, in the present embodiment, it is desirable for at least one of (b) the presence or absence of the common drive and (a) the number of drops which have become relatively high in importance to be at least included as the second explanatory variable group Prin 2  described above. Further, in the present embodiment, as described above, it can be said that it is desirable for at least one of (f) the head rank value, (k) the voltage shift amount ΔVp, (c) the head type, (i) the specific gravity value of the ink  9 , (h) the surface tension value of the ink  9 , (g) the viscosity value at the reference temperature Tr, and (j) the target value of Vj which are the next highest after the parameters described above (the third highest through the ninth highest) to further be included as the second explanatory variable group Prin 2 . 
     Here,  FIG.  12 A  and  FIG.  12 B  are each a diagram showing an example of a correspondence relationship between the predicted value (the SVM predicted value, the RF predicted value) and the measured value when using only the first explanatory variable group Print shown in  FIG.  11 A . Further,  FIG.  13 A  and  FIG.  13 B  are each a diagram showing an example of a correspondence relationship between the predicted value (the SVM predicted value, the RF predicted value) and the measured value when using only the second explanatory variable group Prin 2  shown in  FIG.  11 B . 
     It should be noted that the details of these drawings, namely  FIG.  12 A ,  FIG.  12 B ,  FIG.  13 A , and  FIG.  13 B , are substantially the same as the case of  FIG.  9 A ,  FIG.  9 B  described above. Specifically, in each of the examples shown in  FIG.  12 A ,  FIG.  12 B ,  FIG.  13 A , and  FIG.  13 B , the (x,y) coordinate in each of a number of (562) samples is plotted when defining the measured value of the voltage sensitivity Vr as a variable x, and defining the predicted value (the SVM predicted value or the RF predicted value) of the voltage sensitivity Vr as a variable y. Further, in  FIG.  12 A ,  FIG.  12 B ,  FIG.  13 A , and  FIG.  13 B  described above, an example of a formula (e.g., a linear function formula identified using the least-square method) representing the tendency of the correlative relationship between these variables x, y is also shown. 
     In each of the examples shown in  FIG.  12 A ,  FIG.  12 B ,  FIG.  13 A , and  FIG.  13 B  described above, the gradient in the formula of the linear function described above is made nearly “1,” and at the same time, the intercept in the formula of this linear function is made nearly “0” unlike the case ( FIG.  9 A ,  FIG.  9 B ) of Comparative Example 1 described above. Therefore, in the present embodiment, unlike Comparative Example 1 described above, regarding the voltage sensitivity Vr as the objective variable, the predicted values (the SVM predicted value and the RF predicted value) and the measured value are in the following relationship. That is, it is understood that the predicted value and the measured value have a sufficient correlative relationship to the extent that the predicted value is practicable when performing printing using the predicted value. 
     (D. Functions/Advantages) 
     In such a manner as described above, in the jet parameter generation system  5  according to the present embodiment, which one of the DV standard and the Vj standard described above is selected is determined based on the selection instruction signal Ss. Further, since the jet parameters Prj are generated by using the predetermined analytical method described above using just one of the first explanatory variable group Print and the second explanatory variable group Prin 2  selected in accordance with such a determination result of the standard, the following is achieved. 
     In other words, there is avoided such a degradation of the prediction accuracy of the jet parameters Prj as in, for example, the case (when using the predetermined analytical method in the condition in which both of the DV standard and the Vj standard are mixed with each other) of Comparative Example  1  described above. In other words, in the present embodiment, it is possible to increase the prediction accuracy of the jet parameter Prj compared to the case of Comparative Example 1 described above. As a result, in the present embodiment, it becomes possible to enhance the convenience of the user. 
     Further, in the present embodiment, since at least the voltage sensitivity Vr described above is included as such jet parameter Prj, the following is achieved. In other words, it becomes possible to increase the prediction accuracy of the voltage sensitivity Vr compared to the case of Comparative Example 1 described above when generating the voltage sensitivity Vr using the predetermined analytical method. 
     Further, in the present embodiment, since at least the target value of DV described above is included as the first explanatory variable group Print, and at the same time, at least one of the parameter representing the presence or absence of the common drive described above and the parameter representing the number of drops is included as the second explanatory variable group Prin 2 , the following is achieved. In other words, since the voltage sensitivity Vr is generated using the parameter the highest in importance (degree of contribution) or the parameter the second highest in importance (degree of contribution) when generating the voltage sensitivity Vr using the predetermined analytical method, it becomes possible to further increase the prediction accuracy of the voltage sensitivity Vr. 
     In addition, in the present embodiment, since the number of drops is further included as the first explanatory variable group Print, and at the same time, at least one of the parameters of the head rank value, the head type, the specific gravity value of the ink  9 , the surface tension value of the ink  9 , the viscosity value at the reference temperature Tr, and the target value of DV is further included as the second explanatory variable group Prin 2 , the following is achieved. In other words, since the voltage sensitivity Vr is generated further using these parameters relatively high in importance (degree of contribution) when generating the voltage sensitivity Vr using the predetermined analytical method, it becomes possible to further increase the prediction accuracy of the voltage sensitivity Vr. 
     Further, in the present embodiment, since the voltage shift amount ΔVp described above is included as at least one of the first explanatory variable group Print and the second explanatory variable group Prin 2 , the following is achieved. In other words, it becomes possible to further increase the prediction accuracy of the voltage sensitivity Vr when generating the voltage sensitivity Vr using the predetermined analytical method. 
     Further, in the present embodiment, since there is adopted the method of using the machine learning model  74  as the predetermined analytical method, it becomes possible to easily and accurately generate the jet parameters Prj. 
     In addition, in the present embodiment, since it is configured to further dispose the table generation section  733  and the signal generation section  48  in the jet parameter generation system  5 , the following is achieved. That is, it results in that the predictive voltage characteristic table TPvp is generated using at least one of the generated jet parameters Prj, and at the same time, the voltage value Vp (the crest value) of the pulse is obtained using the predictive voltage characteristic table TPvp generated in such a manner, and the drive signal Sd is generated using the pulse having the voltage value Vp. Therefore, since the jet operation of the ink  9  is performed using the drive signal Sd generated in such a manner, it is possible to easily improve the ejection characteristic of the ink  9 . As a result, it becomes possible to further enhance the convenience of the user. 
     In addition, in the present embodiment, since it is configured that the data acquisition section  731 , the parameter generation section  732 , and the table generation section  733  described above are each disposed outside (in the information processing device  7 ) the printer  1 , the following is achieved. That is, it is possible to perform an automatic generation of the jet parameters Prj and the predictive voltage characteristic table TPvp in the information processing device  7  described above while keeping the existing configuration with respect to the inkjet heads  4  and the printer  1 . As a result, it becomes possible to further enhance the convenience of the user. 
     2. MODIFIED EXAMPLES 
     Then, some modified examples (Modified Example 1 through Modified Example 6) of the embodiment described above will be described. It should be noted that the same constituents as those in the embodiment described above are denoted by the same reference symbols, and the description thereof will arbitrarily be omitted. 
     Modified Example 1 
     In the embodiment described above, there is described when at least the voltage sensitivity Vr is included as the predetermined jet parameters Prj. In contrast, in Modified Example 1 described below, there is described an example of the case including at least a conversion coefficient Kc in the predetermined conversion processing described above as the predetermined jet parameters Prj. In other words, the conversion coefficient Kc corresponds to a specific example of the “predetermined jet parameter” in the present disclosure. 
     Here, the predetermined conversion processing described above is conversion processing from a measured characteristic curve CMvi to a predictive characteristic curve CPvp. Further, the measured viscosity characteristic table TMvi means a characteristic table defining the measured characteristic curve CMvi between the viscosity Vi of the ink  9  and an ambient temperature Ta although the details will be described later. Further, the predictive voltage characteristic table TPvp is a characteristic table for defining the predictive characteristic curve CPvp between the voltage value Vp representing the crest value of the pulse of the drive signal Sd based on a predetermined standard value and the ambient temperature Ta although the details will be described later. It should be noted that the details will be described later. 
     (A. Configuration) 
       FIG.  14    is a block diagram showing a configuration example of a machine learning model (a machine learning model  74 A) related to Modified Example 1. The machine learning model  74 A is a predictive model obtained by performing the machine learning taking the input parameters Prin as the explanatory variables and taking the jet parameter Prj as the objective variable similarly to the machine learning model  74  described in the embodiment. Further, as shown in  FIG.  14   , the machine learning model  74 A is configured to generate (predict) the jet parameter Prj (the objective variable) based on a learning result, and then output the jet parameter Prj thus generated when the input parameters Prin (the explanatory variables) are input. Then, as described above, the machine learning model  74 A generates the predetermined jet parameter Prj so as to include at least the conversion coefficient Kc described above as an example (see  FIG.  14   ). 
     Such a machine learning model  74 A is configured to be used in the parameter generation section  732  similarly to the embodiment. Specifically, the parameter generation section  732  in Modified Example 1 is configured to generate the jet parameter Prj (the conversion coefficient Kc or the like) based on the input parameters Prin using the analytical method using the machine learning model  74 A. It should be noted that a specific example of the analytical method (a prediction method) using such a machine learning model  74 A is substantially the same as that cited in the embodiment. 
     (B. Regarding Details of Conversion Processing, Etc.) 
     Here, the details of the predetermined conversion processing described above, the measured viscosity characteristic table TMvi, and the predictive voltage characteristic table TPvp will hereinafter be described while citing a comparative example (Comparative Example 2). Further, the details of processing in the information processor  73  (the data acquisition section  731 , the parameter generation section  732 , and the table generation section  733 ) described in the embodiment will also be described. 
     B- 1 . Comparative Example 2 
       FIG.  15    is a block diagram showing a schematic configuration example of a printer  101  as a liquid jet recording device according to Comparative Example 2. The printer  101  in the comparative example is provided with the nozzle plate  41 , the actuator plate  42 , the signal generation section  48 , and the driver  49  described above in an inkjet head or the like in Comparative Example 2 not shown. 
     It should be noted that in the printer  101  of Comparative Example 2, unlike the printer  1  according to the embodiment, the signal generation section  48  is configured to set the voltage value Vp using viscosity information Iv described hereinafter instead of the predictive voltage characteristic table TPvp described above. 
       FIG.  16    shows an example of the viscosity information Iv related to such Comparative Example 2. Specifically, in  FIG.  16   , there is shown an example of a correspondence relationship (information including the viscosity information Iv) between the ambient temperature Ta and the viscosity Vi (measured value) of the ink  9 , between the ambient temperature Ta and the voltage value Vp (measured values) in the pulse of the drive signal Sd, and between the ambient temperature Ta and a difference value ΔV (=Vi−Vp) between the viscosity Vi and the voltage value Vp. In other words, in the example shown in  FIG.  16   , there are shown a characteristic curve (a measured characteristic curve CMvi) between the viscosity Vi (measured values) and the ambient temperature Ta, a characteristic curve (a measured characteristic curve CMvp) between the voltage value Vp (measured value) and the ambient temperature Ta, and a characteristic curve between the difference value ΔV described above and the ambient temperature Ta. 
     It should be noted that the ambient temperature Ta described above corresponds to a specific example of the “temperature” in the present disclosure. 
     In Comparative Example 2, first, it is configured that such viscosity information Iv as shown in  FIG.  16    can be obtained by detecting (performing the measurement at a plurality of points such as no less than 5 points) a change in viscosity Vi of the ink  9  with respect to a change in the ambient temperature Ta. Further, it has been known that the change in the viscosity Vi of the ink  9  with respect to the ambient temperature Ta, and the change in the voltage value Vp (the voltage value Vp with which a standard ejection speed can be obtained) with respect to the ambient temperature Ta show respective variation characteristics similar to each other as shown in, for example,  FIG.  16   . Therefore, the difference value ΔV between the viscosity Vi and the voltage value Vp is configured to show a substantially constant value without depending on the ambient temperature Ta as shown in, for example,  FIG.  16   . 
     Further, as shown in  FIG.  16   , the signal generation section  48  in Comparative Example 2 subtracts the difference value ΔV (a negative value) calculated in advance from a value of the viscosity Vi (see the viscosity information Iv) at a certain ambient temperature Ta to thereby obtain the voltage value Vp with which the standard ejection speed can be obtained using such similarity in variation characteristic with temperature. In other words, the signal generation section  48  in Comparative Example 2 uses the relational expression (see  FIG.  16   ) of Vp=(Vi−ΔV) to thereby obtain the voltage value Vp at a certain ambient temperature Ta. 
     Incidentally, the characteristic curve (the measured characteristic curve CMvp described above) between the voltage value Vp and the ambient temperature Ta generally becomes a curve having the gradient differing in accordance with a type of the number of pulses included in the drive signal Sd, a class or a role of each of the pulses (a class and a role of each of the pulses including an additional pulse such as an auxiliary pulse), and so on. Therefore, in Comparative Example 2, it is necessary to obtain such a measured characteristic curve CMvp by basically performing a measurement manually in advance. It should be noted that it is possible to derive such a measured characteristic curve CMvp without performing the actual measurement in a limited condition (e.g., the case of “one drop” described above based on the ejection speed). 
     It is necessary to obtain the measured characteristic curve CMvp described above in such a manner by performing the actual measurement, for example, for each of the types of the number of pulses included in the drive signal Sd. Therefore, an immense amount of time and trouble is required for the user of the printer  101  in Comparative Example 2, and the work burden and the operation cost increase as a result. 
     Here,  FIG.  17    is a diagram showing an example of a variety of characteristic curves (the measured characteristic curve CMvp and the measured characteristic curve CMvi) related to Comparative Example 2. Specifically, in the measured characteristic curves CMvp shown in  FIG.  17   , there are shown the cases in which the number of pulses described above (the number of drops described above) is one (described as “1d ”), three (described as “3d”), seven (described as “7d”), and nine (described as “9d”), respectively. Further, in each of the measured characteristic curves CMvp shown in  FIG.  17   , there is shown the voltage value Vp based on a predetermined standard value. In other words, in the measured characteristic curves CMvp shown in  FIG.  9   , there are shown the voltage value Vp (described as “Vj standard”) with which the standard ejection speed can be obtained when the ink  9  is jetted, and the voltage value Vp (described as “DV standard”) with which a standard drop volume (DV) of the ink  9  can be obtained when the ink  9  is jetted. It should be noted that the drive waveforms when obtaining the variety of characteristic curves shown in  FIG.  17    include the case of “common drive” described later with respect to all of the conditions (the number of drops). 
     In the example shown in  FIG.  17   , as described above, the gradient and so on of the measured characteristic curve CMvp differ in accordance with the type of the number of pulses (the number of drops) and the type (the Vj standard or the DV standard described above) of the predetermined standard value described above. Therefore, when arranging that the single measured characteristic curve CMvp is used in two or more cases when generating the drive signal Sd as in the case of the viscosity information Iv in Comparative Example 2 shown in, for example,  FIG.  16   , the setting accuracy of the voltage value Vp degrades as a result due to a difference in gradient corresponding to the type of the number of pulses, the type of the predetermined standard value, the class, the role, and so on of the pulses described above. Therefore, it becomes difficult to accurately set the voltage value Vp (the crest value) of the pulse in the drive signal Sd. 
     Specifically, in Comparative Example 2, a single voltage characteristic table (the case of “one drop” based on the ejection speed and so on as described above) can only be generated based on, for example, the measured characteristic curve CMvi as a result. Further, as described above, in order to obtain the measured characteristic curves CMvp of the respective conditions (for the types of the number of pulses and so on), the immense amount of trouble is required for the measurement. With all these factors, in the method of Comparative Example 2, there is a possibility that the convenience of the user is impaired due to the degradation of the setting accuracy of the voltage value Vp described above, the increase in work burden of the user, and so on. 
     B-2. Method of Modified Example 1 
     Therefore, in Modified Example 1, the conversion coefficient Kc when performing the conversion processing described hereinafter is generated using the predetermined analytical method described above in the information processor  73  (a program  730 ) described above. Further, in Modified Example 1, it is configured that the characteristic table described above (the predictive voltage characteristic table TPvp for defining the predictive characteristic curve CPvp) is generated at any time (is automatically generated) using the conversion coefficient Kc generated in such a manner. 
     Here,  FIG.  18    is a flowchart showing an example (corresponding to a specific example of processing in the step S 13  in  FIG.  21    described later) of the conversion processing described later according to Modified Example 1. Further,  FIG.  19    shows an example of a variety of characteristic curves (characteristic curves after executing the step S 132  described later shown in  FIG.  18   ) related to Modified Example 1. Specifically,  FIG.  19    shows an example of a variety of characteristic curves (the measured characteristic curve CMvi, a preliminary characteristic curve CPvp 0  of the predictive characteristic curve CPvp described above, and so on) representing a correspondence relationship between the viscosity Vi [mPa] of the ink  9  or the voltage value Vp, and the ambient temperature Ta [° C.]. 
     It should be noted that a preliminary characteristic curve CMvp 0  shown in  FIG.  19    for the sake of convenience forms a characteristic curve obtained by performing predetermined processing (processing for achieving the voltage value Vp=0 at a predetermined reference temperature Tr described later) on the measured characteristic curve CMvp described above so as to easily be compared (in gradient) with the preliminary characteristic curve CPvp 0  described above. 
     Further,  FIG.  20    is a diagram showing an example of the input parameters Prin related to Modified Example 1. It should be noted that in  FIG.  20   , the values of the input parameters Prin are shown with respect to six samples (“sample  1 ” through “sample  6 ”). 
     (Regarding Conversion Processing) 
     First, as shown in, for example,  FIG.  18    and  FIG.  19   , the conversion processing using the conversion coefficient Kc means the processing of converting the measured characteristic curve CMvi into the predictive characteristic curve CPvp as described above. Further, as shown in the example in  FIG.  19   , it is understood that the preliminary characteristic curve CPvp 0  obtained in such conversion processing coincides with accuracy (substantially coincides) with the preliminary characteristic curve CMvp 0  with respect to the measured characteristic curve CMvp described above. 
     Here, a specific example of such conversion processing will be described with reference to  FIG.  18    and  FIG.  19   . 
     In this conversion processing, first, a multiplication operation (CMvi×Kc) of multiplying the measured characteristic curve CMvi by the conversion coefficient Kc is performed (step S 131  shown in  FIG.  18   ). Then, the preliminary characteristic curve CPvp 0  (the preliminary characteristic curve between the predicted value of the voltage value Vp and the ambient temperature Ta) described above is generated (step S 132 ) by performing a subtraction operation on the result of the multiplication operation in the step S 131  so that the voltage value Vp=0 is achieved at the predetermined reference temperature Tr (Tr=40° C. in the example shown in  FIG.  19   ). In other words, due to such preliminary processing (the processing in the steps S 131 , S 132 ), such a preliminary characteristic curve CPvp 0  as shown in, for example,  FIG.  19    is generated as a result from the measured characteristic curve CMvi using the conversion coefficient Kc. It should be noted that the execution sequence of the processing in the steps S 131 , S 132  when executing such preliminary processing can be, for example, an opposite execution sequence (a sequence in which the step S 132  is executed first, and then the step S 131  is executed) to that in the example shown in  FIG.  18   . 
     Subsequently, an add operation (CPvp 0 +ΔVp) of adding a predetermined voltage shift amount ΔVp to the voltage value Vp in the preliminary characteristic curve CPvp 0  is performed so as to achieve the voltage value Vp in (the DV standard or the Vj standard) described above with reference to  FIG.  17    to generate (step S 133 ) the determinative predictive characteristic curve CPvp. In other words, such a voltage value Vp (the voltage value Vp in the predictive characteristic curve CPvp) after adding the voltage shift amount ΔVp corresponds to the voltage value Vp with which the standard drop volume of the ink  9  can be obtained, or the voltage value Vp with which the standard ejection speed can be obtained, when the ink  9  is jetted. In such a manner, the determinative predictive characteristic curve CPvp is generated, and the sequence of conversion processing shown in  FIG.  18    is terminated. 
     Incidentally, the specific conversion equation when performing such conversion processing is expressed as the following formula (1) using the conversion coefficient Kc described above. 
         H =( H   0   ×e   (E/kT) )/ Kc    (1)
 
     H: a value obtained by performing the conversion processing on the viscosity value of the ink  9   
     H 0 : a constant 
     T: absolute temperature (the ambient temperature Ta) 
     E: activation energy 
     k: Boltzmann constant 
     It should be noted that the formula obtained by removing the conversion coefficient Kc from the formula (1) described above is called Arrhenius equation (law), and is well known to the public. Further, the reason that the Arrhenius equation is divided by the conversion coefficient Kc in the formula (1) is that the calculation using (the viscosity value of the ink  9 )/(the measured value of the voltage value Vp) is performed when performing the analytical method using the machine learning model  74 A. Therefore, for example, when performing the calculation using (the measured value of the voltage value Vp)/(the viscosity value of the ink  9 ), conversely, when performing the analytical method using the machine learning model  74 A, a formula of multiplying the Arrhenius equation described above by the conversion coefficient Kc becomes the conversion equation when performing the conversion processing described above. In other words, it can be said that either of these can be used as the conversion equation when performing the conversion processing. 
     (Regarding Input Parameters Prin) 
     Here, as specific examples of the input parameters Prin described above in Modified Example 1, there can be cited those listed below in (a) through (k), and (l) described in the embodiment as shown in  FIG.  20   . 
     (a) the number of drops (the number of pulses) 
     (b) presence or absence of the common drive 
     (c) the head type 
     (d) the ink type 
     (e) (the DV standard or the Vj standard) 
     (f) the head rank value 
     (g) the viscosity value at the reference temperature Tr 
     (l) the voltage sensitivity Vr when performing ejection 
     (h) the surface tension value of the ink  9   
     (i) the specific gravity value of the ink  9   
     (k) the voltage shift amount ΔVp 
     (j) the target value of DV or Vj 
     (Regarding Details of Processing of Generating Characteristic Table, Etc.) 
     Here,  FIG.  21    is a flowchart showing processing of generating the characteristic table (the predictive voltage characteristic table TPvp) and so on related to Modified Example 1. It should be noted that out of a series of processing (steps S 10  through S 16  described later) shown in  FIG.  21   , the processing in the steps S 11  through S 13  described later corresponds to the processing of generating the predictive voltage characteristic table TPvp, and the processing in the steps S 14 , S 15  described later corresponds to the processing of generating the drive signal Sd. 
     In the series of processing shown in  FIG.  21   , the information processor  73  (the program  730 ) first makes (step S 10 ) a judgment on whether or not it is necessary to generate (update) the predictive voltage characteristic table TPvp which defines the predictive characteristic curve CPvp described above as a preliminary step. Here, when it has been judged that it is necessary to generate the predictive voltage characteristic table TPvp (Y in the step S 10 ), there is made the transition to the processing of generating the predictive voltage characteristic table TPvp (steps S 11  through S 13 ) described hereinafter. In contrast, when it has been judged that it is unnecessary to generate the predictive voltage characteristic table TPvp (N in the step S 10 ), the transition to the step S 15  described later is made, and the operation of generating the drive signal Sd is performed as a result using the pulse having the voltage value Vp (the crest value) in the present stage. 
     It should be noted that as an example of the case in which it is necessary to generate the predictive voltage characteristic table TPvp, there can be cited, for example, the following cases. That is, there can be cited, for example, when a predetermined time has elapsed, when the cartridge of the ink tank  3  is mounted, when a predetermined operation signal from the user has been input to the printer  1 , and when a non-ejection period (an idle period) of the ink  9  has become longer than a predetermined time. Further, there can also be cited, for example, when the color, the type, or the like of the ink  9  in the ink tank  3  has been changed, and when the inkjet head  4  of a different model has been installed in the printer  1 . Further, there can also be cited, for example, when at least one of input parameters Prin as shown in  FIG.  20    has been changed. 
     (Steps S 11  Through S 13 : Processing of Generating Predictive Voltage Characteristic Table TPvp) 
     Subsequently, in the processing of generating the predictive voltage characteristic table TPvp (steps S 11  through S 13 ), first, the data acquisition section  731  obtains the following data (the input data). Specifically, the data acquisition section  731  obtains (step S 11 ) each of the measured viscosity characteristic table TMvi defining the measured characteristic curve CMvi between the viscosity Vi of the ink  9  and the ambient temperature Ta, and the predetermined input parameters Prin described above as the input data using the method described above. 
     Then, the parameter generation section  732  generates (step S 12 ) the conversion coefficient Kc based on the input parameters Prin using the predetermined analytical method which takes the input parameters Prin obtained in the step S 11  as the explanatory variables, and takes the conversion coefficient Kc as the jet parameter Prj as the objective variable. Specifically, in Modified Example 1, the parameter generation section  732  generates the conversion coefficient Kc based on the input parameters Prin utilizing the analytical method using the machine learning model  74 A described above. 
     Then, the table generation section  733  performs the predetermined conversion processing (see  FIG.  18   ,  FIG.  19   ) described above using the measured viscosity characteristic table TMvi obtained in the step S 11  and the conversion coefficient Kc generated in the step S 12  to thereby generate (step S 13 ) the predictive voltage characteristic table TPvp. In such a manner, as described above, there is generated the predictive voltage characteristic table TPvp which defines the predictive characteristic curve CPvp between the voltage value Vp (the crest value) of the pulse of the drive signal Sd and the ambient temperature Ta. 
     (Steps S 14 , S 15 : Processing of Generating Drive Signal Sd) 
     Subsequently, in the processing of generating the drive signal Sd (steps S 14 , S 15 ), first, the signal generation section  48  obtains (step S 14 ) the voltage value Vp (the crest value) in the pulse of the drive signal Sd with the method (see  FIG.  6 A  through  FIG.  6 C ) described above using the predictive voltage characteristic table TPvp generated in the step S 13 . Specifically, it is configured that the voltage value Vp of the pulse can be obtained by applying the current ambient temperature Ta to the predictive voltage characteristic table TPvp. 
     Then, the signal generation section  48  generates (step S 15 ) such a drive signal Sd as shown in, for example,  FIG.  6 A  through  FIG.  6 C  described above using the pulse having the voltage value Vp obtained in the step S 14  and, for example, the pulse width Wp set in advance. 
     Incidentally, it is configured that the pulse width Wp described above can be obtained based on, for example, an on-pulse peak (AP) in the pulse. The AP corresponds to a period ( 1  AP=(characteristic vibration period of the ink  9 )/2) half as large as the characteristic vibration period of the ink  9  in the ejection channel described above. Further, when the pulse width Wp is set to the AP, the jetting speed (the ejection efficiency) of the ink  9  is maximized when ejecting (making one droplet ejection of) the ink  9  as much as one normal droplet. Further, the AP is configured to be defined by, for example, the shape of the ejection channel and a physical property value (the specific gravity or the like) of the ink  9 . 
     Further, it is configured that the pulse width Wp is set in, for example, the following manner based on such an AP. That is, in the case of the examples of the drive signal Sd shown in, for example,  FIG.  6 A  through  FIG.  6 C  described above (the examples of the cases of so-called “one drop,” “two drops,” and “three drops,” respectively), the signal generation section  48  sets the pulse widths Wp in the following manner. That is, in the examples of  FIG.  6 A  through  FIG.  6 C , the signal generation section  48  sets the pulse widths Wp so that, for example, the pulse widths Wp described above fulfill the relationships represented by the formula (2) and the formula (3) described below with the AP. It should be noted that the examples represented by the formula (2) and the formula (3) are not a limitation, and it is possible to arbitrarily set the pulse widths Wp. 
       (1.25 ×AP )≤( Wpa 1,  Wpa 2,  Wpa 3,  Wpb 2,  Wpb     3 , Wpc 3)≤(1.75× AP )   (2)
 
       ( Wpa 1)≥( Wpa 2,  Wpb 2)≥( Wpa 3,  Wpb 3,  Wpc 3)   (3)
 
     (Step S 16 : Jet Operation of Ink  9 ) 
     Subsequently, the driver  49  applies the drive signal Sd generated in the step S 15  to the actuator plate  42  described above in the inkjet head  4  to jet (step S 16 ) the ink  9  from the nozzle holes Hn. In such a manner, the jet operation of the ink  9  described above is performed. 
     This terminates the series of processing shown in  FIG.  21   . 
     In such a manner, in the method of Modified Example 1, the conversion coefficient Kc is generated based on the predetermined input parameters Prin by using the predetermined analytical method, and the predictive voltage characteristic table TPvp is generated by performing the conversion processing using the measured viscosity characteristic table TMvi and the conversion coefficient Kc. That is, the predictive voltage characteristic table TPvp which defines the predictive characteristic curve CPvp between the voltage value Vp (the crest value) and the ambient temperature Ta is automatically generated in each case. 
     Thus, in Modified Example 1, the work burden and the operating cost are reduced compared to when obtaining the characteristic curve (the measured characteristic curve CMvp described above) between these voltage values Vp and the ambient temperature Ta by performing the actual measurement (e.g., when obtaining the characteristic curve by performing the actual measurement for each of the types of the number of pulses included in the drive signal Sd) as in, for example, Comparative Example 2described above. Further, the characteristic curve (the measured characteristic curve CMvp) between the voltage value Vp described above and the ambient temperature Ta generally becomes a curve different in gradient and so on in accordance with the type of the number of pulses included in the drive signal Sd, the class and the role of each of the pulses, and so on as described above, and therefore, the predictive voltage characteristic table TPvp is automatically generated in each case, and thus, the following results. That is, it is possible to accurately set the voltage value Vp (the crest value) of the pulse in the drive signal Sd compared to when, for example, using a single characteristic curve in two or more cases. 
     Due to the facts described above, in Modified Example 1, it is possible to increase the efficiency of the work for obtaining the characteristic curve (the voltage characteristic table) between the voltage value Vp described above and the ambient temperature Ta, and at the same time, it is possible to easily improve the setting accuracy of the voltage value Vp (the crest value) of the pulse in the drive signal Sd. 
     Further, in Modified Example 1, for example, it becomes possible to obtain such advantages as described below.
         Since the characteristic curve between the voltage value Vp described above and the ambient temperature Ta can easily be obtained, the voltage control of making the ejection speed and the drop volume of the ink  9  substantially constant becomes easy even when, for example, the type of the number of pulses described above, the class and the role of each of the pulses, and so on are different.   Since expensive evaluation equipment (a temperature controller and so on) used when obtaining the measured characteristic curve CMvp in such a manner as in Comparative Example 2 described above becomes unnecessary, it becomes possible to reduce the cost.       

     C. Comparative Example 3 
     It should be noted that also in Modified Example 1, such a case as described above can occur depending on the condition as described above in the embodiment. In other words, there is a case in which the prediction accuracy of the jet parameters Prj in, for example, the DV standard or the Vj standard degrades when using the predetermined analytical method in the condition in which both of the DV standard and the Vj standard are mixed with each other (Comparative Example 3) similarly to the case of Comparative Example 1 described above. Such Comparative Example 3 will hereinafter be described. 
       FIG.  22    is a diagram showing an example of an importance analysis result of the input parameters Prin related to Comparative Example 3. In the example shown in  FIG.  22   , the input parameters Prin which are made relatively high in importance (contribution rate) when generating the jet parameter Prj (=the conversion coefficient Kc) using the machine learning model  74 A are as follows. In other words, in the input parameters Prin listed in (a) through (k), and (l) described above, the importance is made higher in the order of (i) the specific gravity value of the ink  9 , (a) the number of drops, (g) the viscosity value at the reference temperature Tr, (k) the voltage shift amount ΔVp, (l) the voltage sensitivity Vr when performing ejection, and (j) the target value of DV or Vj. 
     Therefore, in Comparative Example 3, the predetermined analytical method is used in the condition in which both of the DV standard and the Vj standard are mixed with each other selectively using, for example, these parameters as the input parameter Prin. Then, as described above, the prediction accuracy of the jet parameter Prj in, for example, the DV standard or the Vj standard degrades in some cases also in Comparative Example 3 similarly to the case of Comparative Example 1. As a result, there is a possibility that the convenience of the user degrades also in Comparative Example 3 similarly to the case of Comparative Example 1. 
     D. Processing of Generating Jet Parameters Prj in Modified Example 1 
     Therefore, which one of the DV standard and the Vj standard is to be selected is determined based on the selection instruction signal Ss described above when generating the conversion coefficient Kc as the jet parameter Prj also in Modified Example 1 similarly to the embodiment described above. Further, by using the predetermined analytical method using just one of the first explanatory variable group Print and the second explanatory variable group Prin 2  selected in accordance with such a determination result of the standard, the conversion coefficient Kc as the jet parameter Prj is generated. 
     Here,  FIG.  23 A  is a diagram showing an example of the importance analysis result in the first explanatory variable group Print related to Modified Example 1. Further,  FIG.  23 B  is a diagram showing an example of the importance analysis result in the second explanatory variable group Prin 2  related to Modified Example 1. 
     As shown in  FIG.  23 A , as the first explanatory variable group Print related to Modified Example 1, there is included, for example, at least one of the following parameters out of the input parameters Prin described above. Specifically, in the example shown in  FIG.  23 A , there are included (i) the specific gravity value of the ink  9 , (a) the number of drops, (g) the viscosity value at the reference temperature Tr, (j) the target value of DV, (k) the voltage shift amount ΔVp, (l) the voltage sensitivity Vr when performing ejection, (b) presence or absence of the common drive, (h) the surface tension value of the ink  9 , (f) the head rank value, (c) the head type, and (d) the ink type. Further, as shown in  FIG.  23 A , the importance (the degree of contribution) becomes relatively higher in this order. 
     In contrast, as shown in  FIG.  23 B , as the second explanatory variable group Prin 2  related to Modified Example 1, there is included, for example, at least one of the following parameters out of the input parameters Prin described above. Specifically, in the example shown in  FIG.  23 B , there are included (i) the specific gravity value of the ink  9 , (g) the viscosity value at the reference temperature Tr, (a) the number of drops, (k) the voltage shift amount ΔVp, (l) the voltage sensitivity Vr when performing ejection, (d) the ink type, (h) the surface tension value of the ink  9 , (f) the head rank value, (j) the target value of Vj, (c) the head type, and (b) presence or absence of the common drive. Further, as shown in  FIG.  23 B , the importance (the degree of contribution) becomes relatively higher in this order. 
     Here,  FIG.  24 A  and  FIG.  24 B  are each a diagram showing an example of a correspondence relationship between the predicted value (the SVM predicted value, the RF predicted value) and the measured value when using only the first explanatory variable group Print shown in  FIG.  23 A . Further,  FIG.  25 A  and  FIG.  25 B  are each a diagram showing an example of a correspondence relationship between the predicted value (the SVM predicted value, the RF predicted value) and the measured value when using only the second explanatory variable group Prin 2  shown in  FIG.  23 B . 
     It should be noted that the details of these drawings, namely  FIG.  24 A ,  FIG.  24 B ,  FIG.  25 A , and  FIG.  25 B , are substantially the same as the case of  FIG.  12 A ,  FIG.  12 B ,  FIG.  13 A , and  FIG.  13 B  described above. Specifically, in each of the examples shown in  FIG.  24 A ,  FIG.  24 B ,  FIG.  25 A , and  FIG.  25 B , the (x,y) coordinate in each of a number of ( 562 ) samples is plotted when defining the measured value of the conversion coefficient Kc as the variable x, and defining the predicted value (the SVM predicted value or the RF predicted value) of the conversion coefficient Kc as the variable y. Further, in  FIG.  24 A ,  FIG.  24 B ,  FIG.  25 A , and  FIG.  25 B  described above, an example of a formula (e.g., a linear function formula identified using the least-square method) representing the tendency of the correlative relationship between these variables x, y is also shown. 
     In each of the examples shown in  FIG.  24 A ,  FIG.  24 B ,  FIG.  25 A , and  FIG.  25 B  described above, the gradient in the formula of the linear function described above is made nearly “1,” and at the same time, the intercept in the formula of this linear function is made nearly “0” similarly to the case ( FIG.  12 A ,  FIG.  12 B ,  FIG.  13 A , and  FIG.  13 B ) of the embodiment. Therefore, also in Modified Example 1, unlike Comparative Example 3 described above, regarding the conversion coefficient Kc as the objective variable, the predicted values (the SVM predicted value and the RF predicted value) and the measured value are in the following relationship. That is, it is understood that the predicted value and the measured value have a sufficient correlative relationship to the extent that the predicted value is practicable when performing printing using the predicted value. 
     E. Functions/Advantages 
     In such a manner, also in Modified Example 1, it is also possible to obtain basically the same advantages due to substantially the same function as that of the embodiment. 
     Further, in particular, in Modified Example 1, since the conversion coefficient Kc when performing the predetermined conversion processing described above is at least included as the jet parameter Prj, the following is achieved. In other words, it is possible to increase the prediction accuracy of the conversion coefficient Kc compared to the case of Comparative Example 3 described above when generating the conversion coefficient Kc using the predetermined analytical method described above. As a result, also in Modified Example 1, it becomes possible to further enhance the convenience of the user. 
     Modified Example 2 
     In the embodiment described above, there is described when the voltage sensitivity Vr is at least included as the predetermined jet parameter Prj, and in Modified Example 1 described above, there is described when the conversion coefficient Kc is at least included as the predetermined jet parameter Prj. In contrast, in Modified Example 2 described below, there is described an example of the case including at least the voltage shift amount ΔVp described above as the predetermined jet parameters Prj. In other words, the voltage shift amount ΔVp corresponds to a specific example of the “predetermined jet parameter” in the present disclosure. 
     (A. Configuration) 
       FIG.  26    is a block diagram showing a configuration example of a machine learning model (a machine learning model  74 B) related to Modified Example 2. The machine learning model  74 B is a predictive model obtained by performing the machine learning taking the input parameters Prin as the explanatory variables and taking the jet parameter Prj as the objective variable similarly to the machine learning models  74 ,  74 A having already been described. Further, as shown in  FIG.  26   , the machine learning model  74 B is configured to generate (predict) the jet parameter Prj (the objective variable) based on a learning result, and then output the jet parameter Prj thus generated when the input parameters Prin (the explanatory variables) are input. Then, as described above, the machine learning model  74 B generates the predetermined jet parameter Prj so as to include at least the voltage shift amount ΔVp described above as an example (see  FIG.  26   ). 
     Such a machine learning model  74 B is configured to be used in the parameter generation section  732  similarly to the embodiment and Modified Example 1. Specifically, the parameter generation section  732  in Modified Example 2 is configured to generate the jet parameter Prj (the voltage shift amount ΔVp or the like) based on the input parameters Prin using the analytical method using the machine learning model  74 B. It should be noted that a specific example of the analytical method (a prediction method) using such a machine learning model  74 B is substantially the same as that cited in the embodiment. 
     (B. Regarding Input Parameters Prin) 
       FIG.  27    is a diagram showing an example of the input parameters Prin related to Modified Example 2. It should be noted that in  FIG.  27   , the values of the input parameters Prin are shown with respect to six samples (“sample  1 ” through “sample  6 ”). 
     As specific examples of the input parameters Prin in Modified Example  2 , there can be cited those listed in (a) through (j), and (l) below described in the embodiment and Modified Example 1 as shown in  FIG.  27   . 
     (a) the number of drops (the number of pulses) 
     (b) presence or absence of the common drive 
     (c) the head type 
     (d) the ink type 
     (e) (the DV standard or the Vj standard) 
     (f) the head rank value 
     (g) the viscosity value at the reference temperature Tr 
     (l) the voltage sensitivity Vr (the DV standard or the Vj standard) when performing ejection 
     (h) the surface tension value of the ink  9   
     (i) the specific gravity value of the ink  9   
     (j) the target value of DV or Vj 
     C. Comparative Example 4 
     Here, also in Modified Example 2, such a case as described above can occur depending on the condition as described above in the embodiment and Modified Example 1. In other words, there is a case in which the prediction accuracy of the jet parameters Prj in, for example, the DV standard or the Vj standard degrades when using the predetermined analytical method in the condition in which both of the DV standard and the Vj standard are mixed with each other (Comparative Example 4) similarly to the case of Comparative Example 1 and Comparative Example 3 described above. Such Comparative Example 4 will hereinafter be described. 
       FIG.  28    is a diagram showing an example of an importance analysis result of the input parameters Prin related to Comparative Example 4. In the example shown in  FIG.  28   , the input parameters Prin which are made relatively high in importance (contribution rate) when generating the jet parameter Prj (=the voltage shift amount ΔVp) using the machine learning model  74 B are as follows. In other words, in the input parameters Prin listed in (a) through (j), and (l) described above, the importance is made higher in the order of (g) the viscosity value at the reference temperature Tr, (b) presence or absence of the common drive, (f) the head rank value, (c) the head type, (i) the specific gravity value of the ink  9 , (l) the voltage sensitivity Vr when performing ejection, (h) the surface tension value of the ink  9 , and (j) the target value of DV or Vj. 
     Therefore, in Comparative Example 4, the predetermined analytical method is used in the condition in which both of the DV standard and the Vj standard are mixed with each other selectively using, for example, these parameters as the input parameter Prin. Then, as described above, the prediction accuracy of the jet parameter Prj in, for example, the DV standard or the Vj standard degrades in some cases also in Comparative Example 4 similarly to the case of Comparative Example 1 and Comparative Example 3. As a result, there is a possibility that the convenience of the user degrades also in Comparative Example 4 similarly to the case of Comparative Example 1 and Comparative Example 3. 
     D. Processing of Generating Jet Parameter Prj in Modified Example 2 
     Therefore, which one of the DV standard and the Vj standard is to be selected is determined based on the selection instruction signal Ss described above when generating the voltage shift amount ΔVp as the jet parameter Prj also in Modified Example 2 similarly to the embodiment and Modified Example 1 described above. Further, by using the predetermined analytical method using just one of the first explanatory variable group Print and the second explanatory variable group Prin 2  selected in accordance with such a determination result of the standard, the voltage shift amount ΔVp as the jet parameter Prj is generated. 
     Here,  FIG.  29 A  is a diagram showing an example of the importance analysis result in the first explanatory variable group Print related to Modified Example 2. Further,  FIG.  29 B  is a diagram showing an example of the importance analysis result in the second explanatory variable group Prin 2  related to Modified Example 2. 
     As shown in  FIG.  29 A , as the first explanatory variable group Print related to Modified Example 2, there is included, for example, at least one of the following parameters out of the input parameters Prin described above. Specifically, in the example shown in  FIG.  29 A , there are included (b) presence or absence of the common drive, (g) the viscosity value at the reference temperature Tr, (f) the head rank value, (c) the head type, (i) the specific gravity value of the ink  9 , (h) the surface tension value of the ink  9 , (l) the voltage sensitivity Vr when performing ejection, (j) the target value of DV, (d) the ink type, and (a) the number of drops. Further, as shown in  FIG.  29 A , the importance (the degree of contribution) becomes relatively higher in this order. 
     In contrast, as shown in  FIG.  29 B , as the second explanatory variable group Prin 2  related to Modified Example 2, there is included, for example, at least one of the following parameters out of the input parameters Prin described above. Specifically, in the example shown in  FIG.  29 B , there are included (l) the voltage sensitivity Vr when performing ejection, (g) the viscosity value at the reference temperature Tr, (f) the head rank value, (c) the head type, (h) the surface tension value of the ink  9 , (i) the specific gravity value of the ink  9 , (b) presence or absence of the common drive, (j) the target value of Vj, (a) the number of drops, and (d) the ink type. Further, as shown in  FIG.  29 B , the importance (the degree of contribution) becomes relatively higher in this order. 
     Here,  FIG.  30 A  and  FIG.  30 B  are each a diagram showing an example of a correspondence relationship between the predicted value (the SVM predicted value, the RF predicted value) and the measured value when using only the first explanatory variable group Print shown in  FIG.  29 A . Further,  FIG.  31 A  and  FIG.  31 B  are each a diagram showing an example of a correspondence relationship between the predicted value (the SVM predicted value, the RF predicted value) and the measured value when using only the second explanatory variable group Prin 2  shown in  FIG.  29 B . 
     It should be noted that the details of these drawings, namely  FIG.  30 A ,  FIG.  30 B ,  FIG.  31 A , and  FIG.  31 B , are substantially the same as the case of  FIG.  12 A ,  FIG.  12 B ,  FIG.  13 A ,  FIG.  13 B ,  FIG.  24 A ,  FIG.  24 B ,  FIG.  25 A , and  FIG.  25 B  described above. In other words, in the examples shown in  FIG.  30 A ,  FIG.  30 B ,  FIG.  31 A , and  FIG.  31 B , when defining the measured value of the voltage shift amount ΔVp as the variable x, and defining the predicted value (the SVM predicted value or the RF predicted value) of the voltage shift amount ΔVp as the variable y, the (x,y) coordinates in a number of ( 562 ) samples are plotted. Further, in  FIG.  30 A ,  FIG.  30 B ,  FIG.  31 A , and  FIG.  31 B  described above, an example of a formula (e.g., a linear function formula identified using the least-square method) representing the tendency of the correlative relationship between these variables x, y is also shown. 
     In each of the examples shown in  FIG.  30 A ,  FIG.  30 B ,  FIG.  31 A , and  FIG.  31 B  described above, the following is achieved basically similarly to the case of the embodiment ( FIG.  12 A ,  FIG.  12 B ,  FIG.  13 A , and  FIG.  13 B ) and the case of Modified Example 1 ( FIG.  24 A ,  FIG.  24 B ,  FIG.  25 A , and  FIG.  25 B ). Specifically, the gradient in the formula of the linear function described above approximates to “1,” and at the same time, the intercept in the formula of the linear function approximates to “0.” Therefore, also in Modified Example 2, unlike Comparative Example 4 described above, regarding the voltage shift amount ΔVp as the objective variable, the predicted values (the SVM predicted value and the RF predicted value) and the measured value are in the following relationship. That is, it is understood that the predicted value and the measured value have a sufficient correlative relationship to the extent that the predicted value is practicable when performing printing using the predicted value. 
     E. Functions/Advantages 
     In such a manner, also in Modified Example 2, it is also possible to obtain basically the same advantages due to substantially the same function as that of the embodiment. 
     Further, in particular, in Modified Example 2, since the voltage shift amount ΔVp used when performing the predetermined conversion processing described above is at least included as the jet parameter Prj, the following is achieved. In other words, it is possible to increase the prediction accuracy of the voltage shift amount ΔVp compared to the case of Comparative Example 4 described above when generating the voltage shift amount ΔVp using the predetermined analytical method described above. As a result, also in Modified Example 2, it becomes possible to further enhance the convenience of the user. 
     Modified Example 3 
     (Configuration) 
       FIG.  32    is a block diagram showing a configuration example of a jet parameter generation system  5 A according to Modified Example 3. The jet parameter generation system  5 A according to Modified Example 3 is provided with the printer  1  having the inkjet heads  4 , and an information processing device  7 A and a server  8  located outside the printer  1 . Further, the printer  1 , the information processing device  7 A, and the server  8  are connected to each other via the network  50 . In other words, the jet parameter generation system  5 A corresponds to a system obtained by providing the information processing device  7 A instead of the information processing device  7 , and at the same time, further providing the server  8  in the jet parameter generation system  5  according to the embodiment. 
     It should be noted that in Modified Example 3, the server  8  described above corresponds to a specific example of the “external device” in the present disclosure. 
     As shown in  FIG.  32   , the information processing device  7 A has the bus  70 , the input section  71 , the display section  72 , the controller  75 , a storage  76 A, and the network IF  77  as a physical block configuration. In other words, the information processing device  7 A corresponds to a device obtained by disposing the storage  76 A instead of the storage  76  in the information processing device  7  in the embodiment shown in  FIG.  4   . Unlike the storage  76 , the storage  76 A does not store the program  730  and the machine learning model  74  described in the embodiment. Therefore, the information processing device  7 A is, for example, made to correspond to a PC having a common (general-purpose) configuration. 
     As shown in  FIG.  32   , the server  8  has a bus  80 , a controller  85 , a storage  86 , and a network IF  87  as a physical block configuration. It should be noted that the controller  85 , the storage  86 , and the network IF  87  are connected to each other via the bus  80 . The controller  85  and the network IF  87  respectively have substantially the same configurations as those of the controller  75  and the network IF  77  in the embodiment ( FIG.  4   ). Further, the storage  86  also has substantially the same configuration as that of the storage  76  in the embodiment ( FIG.  4   ). In other words, as shown in  FIG.  32   , the storage  86  stores the program  730  and the machine learning model  74  described in the embodiment. It should be noted that as described with parentheses in  FIG.  32   , it is possible to arrange that the machine learning models  74 A,  74 B described in Modified Example 1 and the Modified Example 2 are disposed in addition to such a machine learning model  74 , which also applies to Modified Example 4 through Modified Example 6 described later. 
     In such a manner, in the jet parameter generation system  5 A according to Modified Example 3, it is configured that the predetermined jet parameters Prj (and the predictive voltage characteristic table TPvp) described above are generated in the server  8  instead of the information processing device  7 A unlike the jet parameter generation system  5  according to the embodiment. Further, the predictive voltage characteristic table TPvp generated in such a manner is configured to be supplied to the signal generation section  48  in the inkjet head  4  in the printer  1  from the server  8  via the network  50  as shown in  FIG.  32   . 
     (Functions/Advantages) 
     Also in Modified Example 3 having such a configuration, it is possible to obtain substantially the same advantages due to substantially the same function as that of the jet parameter generation system  5  according to the embodiment in the elementary sense as a whole of the jet parameter generation system  5 A. 
     Further, in particular in Modified Example 3, since it is configured that the data acquisition section  731 , the parameter generation section  732 , and the table generation section  733  (the program  730  described above) described above are each disposed outside (in the server  8 ) the printer  1 , the following results. That is, it is possible to perform the automatic generation of the jet parameters Prj and the predictive voltage characteristic table TPvp in the server  8  described above while keeping the existing configuration with respect to the inkjet heads  4  and the printer  1  similarly to the case of the embodiment described above. Further, in Modified Example 3, the existing (general-purpose) configuration can also be used in the information processing device  7 A as described above, and it is possible to obtain substantially the same advantages as in the embodiment using the server  8  which functions as, for example, a cloud server. As a result, in Modified Example  3 , it becomes possible to further enhance the convenience of the user. 
     Modified Example 4 
     (Configuration) 
       FIG.  33    is a block diagram showing a configuration example of a jet parameter generation system  5 B according to Modified Example 4. The jet parameter generation system  5 B according to Modified Example 4 is provided with a printer  1 B having inkjet heads  4 B, and the information processing device  7 A described above. Further, the printer  1 B and the information processing device  7 A are connected to each other via the network  50 . In other words, the jet parameter generation system  5 B corresponds to a system obtained by disposing the information processing device  7 A described above instead of the information processing device  7 , and at the same time, disposing the printer  1 B and the inkjet heads  4 B instead of the printer  1  and the inkjet heads  4 , respectively, in the jet parameter generation system  5  according to the embodiment. 
     It should be noted that the printer  1 B described above corresponds to a specific example of the “liquid jet recording device” in the present disclosure. Further, the inkjet head  4 B described above corresponds to a specific example of the “liquid jet head” in the present disclosure. 
     In Modified Example 4, as shown in  FIG.  33   , the information processor  73  (the data acquisition section  731 , the parameter generation section  732 , and the table generation section  733 ) described above, in other words, the program  730  described above, is disposed in the inkjet head  4 B. Further, the machine learning model  74  described above is also disposed in the inkjet head  4 B. In other words, in Modified Example 4, unlike the embodiment and Modified Example 3, the information processor  73  (the program  730 ) and the machine learning model  74  are disposed in the inkjet head  4 B incorporated in the printer  1 B. 
     (Functions/Advantages) 
     Also in Modified Example 4 having such a configuration, it is possible to obtain substantially the same advantages due to substantially the same function as that of the jet parameter generation system  5  according to the embodiment in the elementary sense as a whole of the jet parameter generation system  5 B. 
     Further, in particular in Modified Example 4, since it is configured that the data acquisition section  731 , the parameter generation section  732 , and the table generation section  733  are each disposed in the printer  1 B, the following results. That is, unlike the embodiment and Modified Example 3, it becomes unnecessary to prepare each of the data acquisition section  731 , the parameter generation section  732 , and the table generation section  733  in the external device (the information processing device  7  or the server  8 ). Thus, it is possible to perform the automatic generation of the jet parameters Prj and the predictive voltage characteristic table TPvp by the printer  1 B itself, and as a result, it becomes possible to further enhance the convenience of the user. 
     Further, in Modified Example 4, since it is configured that the data acquisition section  731 , the parameter generation section  732 , and the table generation section  733  described above are each disposed in the inkjet head  4 B incorporated in the printer  1 B, the following results. That is, it is possible to perform the automatic generation of the jet parameters Prj and the predictive voltage characteristic table TPvp by the inkjet head  4 B itself while keeping the existing configuration with respect to the inkjet heads  4 B and the printer  1 B themselves. As a result, it becomes possible to further enhance the convenience of the user. 
     Modified Example 5 
     (Configuration) 
       FIG.  34    is a block diagram showing a configuration example of a jet parameter generation system  5 C according to Modified Example 5. The jet parameter generation system  5 C according to Modified Example 5 is provided with a printer  1 C having the inkjet heads  4  described above, and the information processing device  7 A described above. Further, the printer  1 C and the information processing device  7 A are connected to each other via the network  50 . In other words, the jet parameter generation system  5 C corresponds to a system obtained by disposing the information processing device  7 A described above instead of the information processing device  7 , and at the same time, providing the printer  1 C instead of the printer  1  in the jet parameter generation system  5  according to the embodiment. 
     It should be noted that the printer  1 C described above corresponds to a specific example of the “liquid jet recording device” in the present disclosure. 
     In Modified Example 5, as shown in  FIG.  34   , the information processor  73  (the data acquisition section  731 , the parameter generation section  732 , and the table generation section  733 ) described above, in other words, the program  730  described above, is disposed in the printer  1 C similarly to Modified Example 4 ( FIG.  33   ). Further, the machine learning model  74  described above is also disposed in the printer  1 C similarly to Modified Example 4. It should be noted that as shown in  FIG.  34   , in Modified Example 5, unlike Modified Example 4, the information processor  73  (the program  730 ) and the machine learning model  74  are all disposed outside the inkjet head  4  in the printer  1 C. 
     (Functions/Advantages) 
     Also in Modified Example 5 having such a configuration, it is possible to obtain substantially the same advantages due to substantially the same function as that of the jet parameter generation system  5  according to the embodiment in the elementary sense as a whole of the jet parameter generation system  5 C. 
     Further, in particular in Modified Example 5, similarly to Modified Example 4 described above, since it is configured that the data acquisition section  731 , the parameter generation section  732 , and the table generation section  733  are each disposed in the printer  1 C, the following results. That is, similarly to the case of Modified Example 4, it is possible to perform the automatic generation of the jet parameters Prj and the predictive voltage characteristic table TPvp by the printer  1 C itself, and as a result, it becomes possible to further enhance the convenience of the user. 
     Modified Example 6 
     (Configuration) 
       FIG.  35    is a block diagram showing a configuration example of an information processor  73 D (a program  730 D) related to Modified Example 6. The information processor  73 D in Modified Example 6 corresponds to a section obtained by further providing the signal generation section  48  described above to the information processor  73  (having the data acquisition section  731 , the parameter generation section  732 , and the table generation section  733 ) described in the embodiment and so on. In other words, the program  730 D in Modified Example 6 corresponds to what is obtained by making the program  730  described in the embodiment and so on further include a function of the processing executed by the signal generation section  48  described above. 
     The configuration of such an information processor  73 D (the program  730 D) corresponds to a section obtained by further disposing the configuration and the function of the signal generation section  48  in addition to the information processor  73  (the program  730 ) in the external device (the information processing device  7  or the server  8 ) of the printer  1  as in, for example, the embodiment or Modified Example 3.In other words, the configuration of the information processor  73 D corresponds to an example in which the configuration and the function of the signal generation section  48  are disposed not in the printer  1  but in the external device (the information processing device  7  or the server  8 ) of the printer  1  unlike the embodiment and Modified Example 3. 
     (Functions/Advantages) 
     In Modified Example 6 having such a configuration, it is also possible to obtain basically the same advantages due to substantially the same function as that of the embodiment. 
     Further, in particular in Modified Example 6, since it is configured that the configuration and the function of the signal generation section  48  are further disposed in the information processor  73 D (the program  730 D), it is possible to execute the operation (the operation of generating the drive signal Sd) of the signal generation section  48  in a lump in the information processor  73 D (the program  730 D). As a result, it becomes possible to further enhance the convenience of the user. 
     3. Other Modified Examples 
     The present disclosure is described hereinabove citing the embodiment and the modified examples, but the present disclosure is not limited to the embodiment and so on, and a variety of modifications can be adopted. 
     For example, in the embodiment and so on described above, the description is presented specifically citing the configuration examples (the shapes, the arrangements, the number and so on) of each of the members in the printer and the inkjet head, but those described in the above embodiment and so on are not limitations, and it is possible to adopt other shapes, arrangements, numbers and so on. Specifically, for example, in the embodiment described above, the description is presented citing the shuttle type printer in which the inkjet heads are translated as an example, but this example is not a limitation, and it is possible to adopt, for example, a single-pass type printer in which the inkjet heads are fixed. Further, in the embodiment and so on described above, the description is presented citing the case in which the ink tanks are housed in a predetermined chassis as an example, but this example is not a limitation, and it is possible to arrange that the ink tanks are disposed outside the chassis. Further, in the embodiment and so on described above, the description is presented mainly citing the case in which the signal generation section is disposed in the inkjet head as an example, but this example is not a limitation, and it is possible to arrange that the signal generation section is disposed outside the inkjet head in the printer. 
     Further, a variety of types of structures can be adopted as the structure of the inkjet head. Specifically, for example, it is possible to adopt a so-called side-shoot type inkjet head which emits the ink  9  from a central portion in the extending direction of each of the ejection channels in the actuator plate. Alternatively, it is possible to adopt, for example, a so-called edge-shoot type inkjet head for ejecting the ink  9  along the extending direction of each of the ejection channels. Further, the type of the printer is not limited to the type described in the embodiment and so on described above, and it is possible to apply a variety of types such as a thermal type (a thermal on-demand type), and an MEMS (Micro Electro-Mechanical Systems) type. 
     Further, in the embodiment and so on described above, the description is presented citing the non-circulation type inkjet head for using the ink  9  without circulating the ink  9  between the ink tank and the inkjet head as an example, but this example is not a limitation. Specifically, for example, it is also possible to apply the present disclosure to a circulation type inkjet head which uses the ink  9  while circulating the ink  9  between the ink tank and the inkjet head. 
     In addition, in the embodiment and so on described above, there is presented the description specifically citing the examples of the processing of generating the jet parameters Prj, the characteristic table (the predictive voltage characteristic table TPvp), and the drive signal Sd, but the examples cited in the embodiment and so on are not limitations. Specifically, for example, it is possible to arrange that the processing of generating the jet parameters Prj, the characteristic table, the drive signal Sd, and so on is performed using other methods. Specifically, in the embodiment and so on described above, the description is presented citing the method using the machine learning model as an example of the predetermined analytical methods described above, but this method is not a limitation, and it is possible to arrange to use other analytical methods. Further, the input parameters Prin described above are not limited to the variety of parameters cited in the embodiment and so on described above, and it is possible to arrange to add other parameters to (or substitute other parameters for) the parameters cited in the embodiment and so on described above to be used in the analytical methods. 
     Further, in the embodiment and so on described above, the description is presented citing an example of the case in which both of the pulse width Wp and the voltage value (the crest value) Vp in the pulse are set (automatically adjusted), and then the drive signal Sd is generated, but this example is not a limitation. Specifically, for example, it is possible to arrange to set only the pulse width Wp out of the pulse width Wp and the voltage value Vp in the pulse, and then generate the drive signal Sd. Further, in the embodiment and so on described above, the description is presented citing the example of the case in which the voltage values Vp in the plurality of pulses are all set to the same value, but it is possible to arrange that, for example, the voltage values Vp in the plurality of pulses are not the same value (at least some of the voltage values Vp are set to a different value). Even in such a case, it is possible to arrange to use the plurality of types of voltage values Vp respectively as the explanatory variables to execute the processing of generating the predictive voltage characteristic table TPvp and so on explained in the embodiment and so on described above. 
     Further, in the embodiment and so on described above, there is presented the description citing each of the voltage sensitivity Vr, the conversion coefficient Kc, and the voltage shift amount ΔVp as an example of the jet parameters Prj, but the examples of these cases are not limitations. Specifically, for example, it is possible to arrange that two or more species of these variety of parameters (the voltage sensitivity Vr, the conversion coefficient Kc, the voltage shift amount ΔVp, and so on) are used in arbitrary combination as the jet parameters Prj. Further, for example, it is possible to arrange to use other parameters than these parameters as the jet parameters Prj. 
     In addition, in the embodiment and so on described above, there is described the case in which the pulses (the pulses Pa, Pb, and Pc) for expanding the volume of each of the ejection channels are the pulses (positive pulses) for expanding the volume during a period in a High state, but this case is not a limitation. Specifically, besides the case of the pulse for expanding the volume during the period in the High state and contracting the volume during a period in a Low state, it is also possible to adopt pulses (negative pulses) for expanding the volume during the period in the Low state and contracting the volume during the period in the High state by contraries. It should be noted that even in the case of such negative pulses, it is possible for the method of exerting the same function as in the “common drive” described above to apply such “common drive.” 
     Further, for example, it is also possible to arrange that a pulse for helping the ejection of the droplet is additionally applied during the OFF period immediately after the ON period. As the pulse for helping the ejection of the droplet, there can be cited, for example, a pulse for contracting the volume of each of the ejection channels, and a pulse (an auxiliary pulse) for pulling back a part of the droplet having been ejected. Further, the pulse (a main pulse) to be applied immediately before the auxiliary pulse as latter one of the pulses has, for example, a pulse width no larger than the width of the on-pulse peak (AP). It should be noted that even if such a pulse for helping the ejection of the droplet is added, the content of the present disclosure described hereinabove is not affected. 
     Further, the series of processing described in the embodiment and so on described above can be configured to be performed by hardware (a circuit), or can also be configured to be performed by software (a program). When arranging that the series of processing is performed by the software, the software is constituted by a program group for making the computer perform the functions. The programs can be incorporated in advance in the computer described above to be used by the computer, for example, or can also be installed in the computer described above from a network or a recording medium to be used by the computer. It should be noted that as the recording medium (a non-transitory computer-readable recording medium) on which such programs are recorded, there can be cited a variety of types of media such as a floppy (a registered trademark) disk, a CD (Compact Disk)-ROM, a DVD (Digital Versatile Disc)-ROM, and a hard disk. 
     Further, in the embodiment and so on described above, the description is presented citing the printer  1  (the inkjet printer) as a specific example of the “liquid jet recording device” in the present disclosure, but this example is not a limitation, and it is also possible to apply the present disclosure to other devices than the inkjet printer. In other words, it is also possible to arrange that the “liquid jet head” (the inkjet head) of the present disclosure is applied to other devices than the inkjet printer. Specifically, it is also possible to arrange that the “liquid jet head” of the present disclosure is applied to a device such as a facsimile or an on-demand printer. 
     In addition, it is also possible to apply the variety of examples described hereinabove in arbitrary combination. 
     It should be noted that the advantages described in the present specification are illustrative only, but are not a limitation, and other advantages can also be provided. 
     Further, the present disclosure can also take the following configurations. 
     &lt;1&gt; A jet parameter generation system configured to generate a predetermined jet parameter to be used when generating a drive signal which is applied to a jet section configured to jet liquid, and which has a single pulse or a plurality of pulses, the system comprising: a data acquisition section configured to obtain a selection instruction signal input from an outside and a predetermined input parameter as input data; and a parameter generation section configured to generate the predetermined jet parameter based on the selection instruction signal and the predetermined input parameter, using a predetermined analytical method taking the predetermined input parameter as an explanatory variable and taking the predetermined jet parameter as an objective variable, wherein the parameter generation section determines which one of a first standard and a second standard is to be selected, based on the selection instruction signal representing which one of the first standard and the second standard is to be selected, a voltage value representing a crest value of the pulse in the drive signal being set to a voltage value with which a drop volume of the liquid to be a reference is obtained based on the first standard, and being set to a voltage value with which an ejection speed of the liquid to be a reference is obtained based on the second standard, selects a first explanatory variable group included in the predetermined input parameter as the explanatory variable when determining that the first standard is to be selected, while selecting a second explanatory variable group included in the predetermine input parameter as the explanatory variable when determining that the second standard is to be selected, and uses the predetermined analytical method using just selected one of the first explanatory variable group and the second explanatory variable group to thereby generate the predetermined jet parameter. 
     &lt;2&gt; The jet parameter generation system according to &lt;1&gt;, wherein at least a voltage sensitivity of the liquid corresponding to a variation per unit voltage in one of a drop volume of the liquid and an ejection speed of the liquid when the liquid is jetted at a reference temperature is included as the predetermined jet parameter. 
     &lt;3&gt; The jet parameter generation system according to &lt;2&gt;, wherein as the first explanatory variable group, there is included at least a target value of the drop volume of the liquid, and as the second explanatory variable group, there is included at least one of parameters of a parameter representing presence or absence of a common drive in the drive signal, and a number of drops corresponding to a number of the pulses included in a unit period in the drive signal. 
     &lt;4&gt; The jet parameter generation system according to &lt;3&gt;, wherein as the first explanatory variable group, there is further included the number of drops, and as the second explanatory variable group, there is further included at least one of parameters of a head rank value which corresponds to the voltage value with which a predetermined ejection speed is achieved when a predetermined test liquid is jetted from the jet section, and which is a value inherent in a liquid jet head having the jet section, a parameter representing a type of the liquid jet head, a specific gravity of the liquid, a surface tension value of the liquid, a viscosity value of the liquid at a reference temperature, and a target value of the ejection speed of the liquid. 
     &lt;5&gt; The jet parameter generation system according to &lt;3&gt; or &lt;4&gt;, wherein as conversion processing from a measured characteristic curve between viscosity and temperature of the liquid to a predictive characteristic curve between the voltage value and temperature to be used when generating the drive signal, there are included preliminary processing of generating a preliminary characteristic curve representing a relationship between the voltage value and temperature from the measured characteristic curve, using a conversion coefficient when performing the conversion processing, and an add operation of adding a voltage shift amount to the voltage value in the preliminary characteristic curve to thereby generate the predictive characteristic curve, and as at least one of the first explanatory variable group and the second explanatory variable group, there is further included the voltage shift amount. 
     &lt;6&gt; The jet parameter generation system according to any one of &lt;1&gt; to &lt;5&gt;, wherein as conversion processing from a measured characteristic curve between viscosity and temperature of the liquid to a predictive characteristic curve between the voltage value and temperature to be used when generating the drive signal, there are included preliminary processing of generating a preliminary characteristic curve representing a relationship between the voltage value and temperature from the measured characteristic curve using a conversion coefficient when performing the conversion processing, and an add operation of adding a voltage shift amount to the voltage value in the preliminary characteristic curve to thereby generate the predictive characteristic curve, and as the predetermined jet parameter, there is included at least the conversion coefficient. 
     &lt;7&gt; The jet parameter generation system according to &lt;6&gt;, wherein as the first explanatory variable group, there is included at least one of parameters of a specific gravity of the liquid, a number of drops corresponding to a number of the pulses included in a unit period in the drive signal, a viscosity value of the liquid at a reference temperature, a target value of an ejection speed of the liquid, the voltage shift amount, a voltage sensitivity of the liquid, a parameter representing presence or absence of a common drive in the drive signal, a surface tension value of the liquid, a head rank value which corresponds to the voltage value with which a predetermined ejection speed is achieved when a predetermined test liquid is jetted from the jet section, and which is a value inherent in a liquid jet head having the jet section, a parameter representing a type of the liquid jet head, and a parameter representing a type of the liquid classified according to a chief solvent of the liquid, and as the second explanatory variable group, there is included at least one of parameters of the specific gravity of the liquid, the viscosity value of the liquid at the reference temperature, the number of drops, the voltage shift amount, the voltage sensitivity of the liquid, the parameter representing the type of the liquid, the surface tension value of the liquid, and the head rank value. 
     &lt;8&gt; The jet parameter generation system according to any one of &lt;1&gt; to &lt;6&gt;, wherein as conversion processing from a measured characteristic curve between viscosity and temperature of the liquid to a predictive characteristic curve between the voltage value and temperature to be used when generating the drive signal, there are included preliminary processing of generating a preliminary characteristic curve representing a relationship between the voltage value and temperature from the measured characteristic curve using a conversion coefficient when performing the conversion processing, and an add operation of adding a voltage shift amount to the voltage value in the preliminary characteristic curve to thereby generate the predictive characteristic curve, and as the predetermined jet parameter, there is included at least the voltage shift amount. 
     &lt;9&gt; The jet parameter generation system according to &lt;8&gt;, wherein as the first explanatory variable group, there is included at least one of parameters of a parameter representing presence or absence of a common drive in the drive signal, a viscosity value of the liquid at the reference temperature, a head rank value which corresponds to the voltage value with which a predetermined ejection speed is achieved when a predetermined test liquid is jetted from the jet section, and which is a value inherent in a liquid jet head having the jet section, a parameter representing a type of the liquid jet head, a specific gravity of the liquid, a surface tension value of the liquid, a voltage sensitivity of the liquid, a target value of an ejection speed of the liquid, a parameter representing a type of the liquid classified according to a chief solvent of the liquid, and a number of drops corresponding to a number of the pulses included in a unit period in the drive signal, and as the second explanatory variable group, there is included at least one of parameters of the voltage sensitivity of the liquid, the viscosity value of the liquid at the reference temperature, the head rank value, the parameter representing the type of the liquid jet head, the surface tension value of the liquid, the specific gravity of the liquid, the parameter representing presence or absence of the common drive in the drive signal, the target value of the ejection speed of the liquid, the number of drops, and the parameter representing the type of the liquid. 
     &lt;10&gt; The jet parameter generation system according to any one of &lt;1&gt; to &lt;9&gt;, wherein the predetermined analytical method is a method using a machine learning model to which the predetermined input parameter is input, and from which the predetermined jet parameter is output. 
     &lt;11&gt; The jet parameter generation system according to any one of &lt;1&gt; to &lt;10&gt;, further comprising: a table generation section configured to perform conversion processing from a measured characteristic curve between viscosity and temperature of the liquid to a predictive characteristic curve between the voltage value and temperature using at least one of the predetermined jet parameter to thereby generate a predictive voltage characteristic table defining the predictive characteristic curve based on a measured viscosity characteristic table defining the measured characteristic curve; and a signal generation section which is configured to obtain a crest value of the pulse using the predictive voltage characteristic table generated by the table generation section, and which is configured to generate the drive signal using the pulse having the crest value obtained. 
     &lt;12&gt; The jet parameter generation system according to any one of &lt;1&gt; to &lt;11&gt;, wherein the data acquisition section and the parameter generation section are disposed in an external device located outside a liquid jet recording device incorporating a liquid jet head having the jet section. 
     &lt;13&gt; The jet parameter generation system according to any one of &lt;1&gt; to &lt;11&gt;, wherein the data acquisition section and the parameter generation section are disposed in a liquid jet recording device incorporating a liquid jet head having the jet section. 
     &lt;14&gt; The jet parameter generation system according to &lt;13&gt;, wherein the data acquisition section and the parameter generation section are disposed in the liquid jet head. 
     &lt;15&gt; A method of generating a predetermined jet parameter to be used when generating a drive signal which is applied to a jet section configured to jet liquid, and which has a single pulse or a plurality of pulses, the method comprising: obtaining a selection instruction signal input from an outside and a predetermined input parameter as input data; and generating the predetermined jet parameter based on the selection instruction signal and the predetermined input parameter, using a predetermined analytical method taking the predetermined input parameter as an explanatory variable and taking the predetermined jet parameter as an objective variable, wherein when generating the predetermined jet parameter, which one of a first standard and a second standard is to be selected is determined based on the selection instruction signal representing which one of the first standard and the second standard is to be selected, a voltage value representing a crest value of the pulse in the drive signal being set to a voltage value with which a drop volume of the liquid to be a reference is obtained based on the first standard, and being set to a voltage value with which an ejection speed of the liquid to be a reference is obtained based on the second standard, a first explanatory variable group included in the predetermined input parameter is selected as the explanatory variable when determining that the first standard is to be selected, while a second explanatory variable group included in the predetermine input parameter is selected as the explanatory variable when determining that the second standard is to be selected, and the predetermined analytical method using just selected one of the first explanatory variable group and the second explanatory variable group is used to thereby generate the predetermined jet parameter. 
     &lt;16&gt; A program of generating a predetermined jet parameter to be used when generating a drive signal which is applied to a jet section configured to jet liquid, and which has a single pulse or a plurality of pulses, the program making a computer execute processing comprising: obtaining a selection instruction signal input from an outside and a predetermined input parameter as input data; and generating the predetermined jet parameter based on the selection instruction signal and the predetermined input parameter, using a predetermined analytical method taking the predetermined input parameter as an explanatory variable and taking the predetermined jet parameter as an objective variable, wherein when generating the predetermined jet parameter, which one of a first standard and a second standard is to be selected is determined based on the selection instruction signal representing which one of the first standard and the second standard is to be selected, a voltage value representing a crest value of the pulse in the drive signal being set to a voltage value with which a drop volume of the liquid to be a reference is obtained based on the first standard, and being set to a voltage value with which an ejection speed of the liquid to be a reference is obtained based on the second standard, a first explanatory variable group included in the predetermined input parameter is selected as the explanatory variable when determining that the first standard is to be selected, while a second explanatory variable group included in the predetermine input parameter is selected as the explanatory variable when determining that the second standard is to be selected, and the predetermined analytical method using just selected one of the first explanatory variable group and the second explanatory variable group is used to thereby generate the predetermined jet parameter. 
     &lt;17&gt; A non-transitory computer-readable storage medium storing a program of generating a predetermined jet parameter to be used when generating a drive signal which is applied to a jet section configured to jet liquid, and which has a single pulse or a plurality of pulses, the program making a computer execute processing comprising: obtaining a selection instruction signal input from an outside and a predetermined input parameter as input data; and generating the predetermined jet parameter based on the selection instruction signal and the predetermined input parameter, using a predetermined analytical method taking the predetermined input parameter as an explanatory variable and taking the predetermined jet parameter as an objective variable, wherein when generating the predetermined jet parameter, which one of a first standard and a second standard is to be selected is determined based on the selection instruction signal representing which one of the first standard and the second standard is to be selected, a voltage value representing a crest value of the pulse in the drive signal being set to a voltage value with which a drop volume of the liquid to be a reference is obtained based on the first standard, and being set to a voltage value with which an ejection speed of the liquid to be a reference is obtained based on the second standard, a first explanatory variable group included in the predetermined input parameter is selected as the explanatory variable when determining that the first standard is to be selected, while a second explanatory variable group included in the predetermine input parameter is selected as the explanatory variable when determining that the second standard is to be selected, and the predetermined analytical method using just selected one of the first explanatory variable group and the second explanatory variable group is used to thereby generate the predetermined jet parameter.