DRIVE WAVEFORM DETERMINATION METHOD, LIQUID EJECTION APPARATUS, AND COMPUTER PROGRAM

Abstract

To determine a drive waveform with which characteristics of discharged liquid hardly change, despite that conditions of an environment used change.SOLUTION: A drive waveform of a drive signal to be applied to a drive element of a liquid discharge head in order to discharge liquid from a liquid discharge head is determined. This method includes: a first acquisition step of executing a first acquisition process for acquiring first information related to discharge characteristics of a liquid when a plurality of drive waveform candidates are applied respectively to a drive element, under first environment conditions that are environment conditions in which the liquid discharged head is situated; a second acquisition step of executing a second acquisition process for acquiring second information related to discharge characteristics when a plurality of drive waveform candidates are applied respectively to a drive element, under second environment conditions that are environment conditions in which the liquid discharge head is situated, and that are different from the first environment conditions; and a waveform determination step of determining a waveform on the basis of the first information and the second information.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a drive waveform determination method, a liquid ejection apparatus, and a computer program. [Background technology]

[0002] Conventionally, there is a method for determining parameters that define the waveform of a drive signal based on the results obtained by ejecting ink droplets and measuring the ejection characteristics in an inkjet printer. In the technology of Patent Document 1, a plurality of drive signals having different values ​​of parameters that define the drive waveform are prepared. Then, ink droplets are ejected simultaneously from a plurality of nozzles using one of the plurality of drive signals. The simultaneous ejection of ink droplets using one drive signal is performed for a plurality of nozzles of different numbers. Such processing is performed for each drive signal. Then, the parameter of the drive signal that causes the smallest deviation in the ejection speed of ink droplets when ink droplets are ejected simultaneously from different numbers of nozzles is adopted as the parameter of the drive signal that is actually used for printing. As a result, in printing, ink droplets are stably ejected from each nozzle regardless of the number of nozzles that eject ink droplets simultaneously. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-131910 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the environmental conditions in which the printer is used, such as temperature and humidity, change, the characteristics of the ink ejected from the nozzle, such as the ejection amount, ejection speed, and amount of sub-droplets, change. Therefore, even if the parameters are determined using the technology of Patent Document 1, desirable ejection characteristics may not be realized when the environmental conditions in which the printer is used change. For example, when electronic devices are manufactured using an inkjet device installed in a clean room, changes in the ejection amount due to temperature changes have a significant effect on the quality of the product. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, there is provided a drive waveform determination method for determining a drive waveform of a drive signal to be applied to a drive element of a liquid ejection head in order to eject liquid from the liquid ejection head, the method including: a first acquisition step of executing a first acquisition process to acquire first information on ejection characteristics of liquid when each of a plurality of drive waveform candidates is applied to a drive element under a first environmental condition that is an environmental condition in which the liquid ejection head is placed; a second acquisition step of executing a second acquisition process to acquire second information on the ejection characteristics when each of the plurality of drive waveform candidates is applied to a drive element under a second environmental condition that is an environmental condition in which the liquid ejection head is placed and is different from the first environmental condition; and a waveform determination step of determining the drive waveform based on the first information and the second information. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a block diagram showing the configurations of a printer 1 and a computer 60 included in a printing system according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view showing part of the configuration of the printer 1. [Diagram 3] 2 is a cross-sectional view of the ink ejection head 41 taken along a cross section perpendicular to the sub-scanning direction Ds. [Figure 4] 13 is a diagram showing a drive waveform W of a drive signal COM. FIG. [Diagram 5]10 is a flowchart showing a method for determining the drive waveform of the drive signal to be applied to the printer 1. [Figure 6] FIG. 11 is a block diagram showing printers 1a, 1b and computers 60a, 60b that configure a printing system according to a second embodiment. [Figure 7] 11 is a flowchart showing a method for determining the drive waveform of a drive signal to be applied to a printer 1b in the second embodiment. [Figure 8] FIG. 11 is a block diagram showing printers 1a and 1b, computers 60a and 60b, and a server 70 that configure a printing system according to a third embodiment. [Figure 9] 13 is a flowchart showing a method for determining the drive waveforms of the drive signals applied to the printers 1a and 1b in the third embodiment. [Figure 10] FIG. 11 is a block diagram showing printers 1a and 1b and a computer 60 that configure a printing system according to a fourth embodiment. [Figure 11] 13 is a flowchart showing a method for determining the drive waveforms of the drive signals applied to the printers 1a and 1b in the fourth embodiment. [Figure 12] 13 is a flowchart showing a method for determining the drive waveforms of the drive signals applied to the printers 1a and 1b in the fifth embodiment. [Figure 13] 13 is a flowchart showing a method for determining a drive waveform of a drive signal in a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] A. First embodiment: A1. Printing system configuration: 1 is a block diagram showing the configurations of a printer 1 and a computer 60 included in the printing system of the first embodiment. The printing system includes the printer 1 and a computer 60.

[0008] The printer 1 drives drive elements based on print data to eject ink droplets from nozzles and form an image on the print medium PM. The printer 1 includes a controller 10, a transport unit 20, a carriage unit 30, a head unit 40, and a detector group 50.

[0009] The controller 10 is a control unit that controls the printer 1. The controller 10 includes an interface unit 11, a CPU 12, a memory 13, and a unit control circuit 14.

[0010] The interface unit 11 transmits and receives data between the printer 1 and the computer 60. The memory 13 includes an auxiliary memory that stores programs executed by the CPU 12, and a main memory that functions as a work area. The CPU 12 is an arithmetic processing device for controlling the entire printer 1. As a processor, the CPU 12 realizes various functions by loading programs stored in the auxiliary memory into the main memory and executing them. The main memory is preferably a non-volatile memory, but may be a volatile memory. Either non-volatile or volatile memory can be suitably used as the auxiliary memory.

[0011] The unit control circuit 14 controls each unit of the printer 1 in response to instructions from the CPU 12. The unit control circuit 14 includes a plurality of drive signal generation circuits 15. The drive signal generation circuits 15 generate a drive signal COM including a drive waveform W at regular intervals.

[0012] The transport unit 20 transports the printing medium PM to a position where printing is possible, and transports the printing medium PM by a transport amount of a predetermined pattern during printing. The carriage unit 30 moves the ink ejection head 41 attached to the carriage 31 in a direction intersecting the transport direction of the printing medium PM. In this specification, the movement direction of the ink ejection head 41 is referred to as the "main scanning direction Dm," and the transport direction of the printing medium PM is referred to as the "sub-scanning direction Ds."

[0013] The head unit 40 ejects ink droplets onto the print medium PM. The head unit 40 includes an ink ejection head 41 and a head controller HC. A plurality of nozzles Nz are provided on the bottom surface of the ink ejection head 41. The ink ejection head 41 includes a plurality of driving elements PZT. Specifically, the driving element PZT is a piezoelectric element. One driving element PZT is provided for each nozzle Nz. The driving element PZT is driven by application of a driving signal COM. The ink ejection head 41 ejects ink from the nozzle Nz by driving the driving element PZT. Note that in this embodiment, a piezoelectric element made of lead zirconate titanate is used as the driving element PZT, but it may be a piezoelectric element made of a material other than lead zirconate titanate, or it may be a heating element.

[0014] The head controller HC controls whether or not to apply the drive waveform W of the drive signal COM to the drive element PZT corresponding to each nozzle Nz based on the print data. When the drive waveform W is applied to the drive element PZT corresponding to a certain nozzle Nz, an amount of ink according to the drive waveform W is ejected from that nozzle Nz, forming a dot on the printing medium PM. On the other hand, if the drive waveform W is not applied to the drive element PZT corresponding to a certain nozzle Nz, no ink droplets are ejected from that nozzle Nz.

[0015] 2 is a perspective view showing part of the configuration of the printer 1. The printer 1 can perform a dot formation process in which ink droplets are intermittently ejected from an ink ejection head 41 that moves along a main scanning direction Dm to form dots on the printing medium PM. The printer 1 can perform a transport process in which the printing medium PM is transported in a sub-scanning direction Ds. The printer 1 alternately repeats the dot formation process and the transport process to form dots at each position on the printing medium PM and form an image.

[0016] The detector group 50 monitors the conditions inside the printer 1 (see the lower part of FIG. 1). In response to output signals from the detector group 50, the controller 10 controls each part that constitutes the printer 1. The detector group 50 includes a temperature sensor 51, a humidity sensor 52, an air pressure sensor 53, and a CCD camera 55.

[0017] The temperature sensor 51 measures the air temperature and outputs a signal representing the air temperature to the CPU 12. The air temperature measured by the temperature sensor 51 is the temperature of the environment in which the ink ejection head 41 is placed. The humidity sensor 52 measures the humidity and outputs a signal representing the humidity to the CPU 12. The humidity measured by the humidity sensor 52 is the humidity of the environment in which the ink ejection head 41 is placed. The air pressure sensor 53 measures the air pressure and outputs a signal representing the air pressure to the CPU 12. The air pressure measured by the air pressure sensor 53 is the air pressure of the environment in which the ink ejection head 41 is placed.

[0018] The CCD camera 55 acquires an image of ink droplets ejected from the ink ejection head 41, and outputs the image data to the CPU 12. The CCD camera 55 can capture still images and moving images. In this specification, the term "image" includes still images and moving images.

[0019] The CCD camera 55 is used for photographing to obtain information representing the discharge characteristics as described below, but any part capable of obtaining information representing the discharge characteristics may be used in place of the CCD camera 55. For example, an electronic balance may be used in place of the CCD camera 55 to obtain information representing the discharge characteristics such as the discharge amount.

[0020] The computer 60 transmits print data to the printer 1. The computer 60 transmits parameters that represent the drive waveform of a drive signal for a drive element to the printer 1. The computer 60 includes an interface unit 61, a CPU 62, a memory 63, a display 64, a keyboard 65, and a mouse 66.

[0021] The display 64 outputs images under the control of the CPU 62. The keyboard 65 and mouse 66 are operated by the user to input user instructions to the CPU 62.

[0022] The interface unit 61 transmits and receives data between the computer 60 and the printer 1. The memory 63 includes an auxiliary memory that stores programs executed by the CPU 62, and a main memory that functions as a work area. The CPU 62 as a processor realizes various functions by loading programs stored in the auxiliary memory into the main memory and executing them.

[0023] For example, the CPU 62 realizes a function of acquiring information indicating ejection characteristics, which are characteristics of the ejection of ink from the ink ejection head 41. More specifically, the CPU 62 can acquire the ejection speed of ink ejected from the nozzles Nz and the ejection amount of ink ejected from one nozzle Nz by the ejection operation of the driving element PZT, based on an image of an ink droplet acquired by the CCD camera 55. The CPU 62 also realizes a function of determining the drive waveform of the driving signal COM applied to the driving element PZT.

[0024] 3 is a cross-sectional view of the ink ejection head 41 taken along a cross section perpendicular to the sub-scanning direction Ds. The ink ejection head 41 has a case 411, a flow passage unit 412, and a plurality of driving elements PZT. The case 411 houses the plurality of driving elements PZT. The flow passage unit 412 is joined to the lower surface of the case 411.

[0025] The flow passage unit 412 includes a flow passage forming plate 412a, an elastic plate 412b, and a nozzle plate 412c.

[0026] The flow path forming plate 412a is formed with a groove portion that functions as a pressure chamber 412d, a through hole that functions as a nozzle communication port 412e, a through hole that functions as a common ink chamber 412f, and a groove portion that functions as an ink supply path 412g. In the ink ejection head 41, ink is supplied to the pressure chamber 412d via the common ink chamber 412f and the ink supply path 412g. The ink in the pressure chamber 412d is ejected from the nozzle Nz via the nozzle communication port 412e. For one nozzle Nz, a combination of the ink supply path 412g, the pressure chamber 412d, and the nozzle communication port 412e is provided.

[0027] The elastic plate 412b has an island portion 412h to which the tip of the driving element PZT is joined. An elastic region is formed around the island portion 412h by an elastic film 412i.

[0028] The nozzle plate 412c is a plate in which a plurality of nozzles Nz are formed. A yellow nozzle row that ejects yellow ink, a magenta nozzle row that ejects magenta ink, a cyan nozzle row that ejects cyan ink, and a black nozzle row that ejects black ink are formed on one surface of the nozzle plate 412c, that is, the nozzle Nz surface. Each nozzle row is composed of 180 nozzles Nz arranged at a predetermined interval in the sub-scanning direction Ds. FIG. 3 is a cross-sectional view of a section perpendicular to the sub-scanning direction Ds. In the unit control circuit 14, one drive signal generation circuit 15 is provided for each nozzle row.

[0029] The multiple driving elements PZT are configured as multiple comb-shaped elements. A driving signal COM is applied to the driving elements PZT by a wiring board on which the head control unit HC and the like are mounted. The driving elements PZT expand and contract in response to the potential of the driving signal COM. When the driving element PZT expands, the island portion 412h deforms toward the pressure chamber 412d. When the driving element PZT contracts, the island portion 412h deforms toward the driving element PZT. As a result, the pressure in the pressure chamber 412d changes, and ink droplets are ejected from the nozzles Nz. One driving signal generating circuit 15 is provided for one nozzle row. Therefore, the driving signal COM generated by a certain driving signal generating circuit 15 is commonly applied to the driving elements PZT of all the nozzles Nz belonging to the nozzle row corresponding to that driving signal generating circuit 15.

[0030] Fig. 4 is a diagram showing a driving waveform W of the driving signal COM. In the driving signal COM, the driving waveform W shown in Fig. 4 is generated repeatedly at a constant cycle.

[0031] The drive waveform W has a first expansion element S1 whose potential increases from an intermediate potential Vc to a maximum potential Vh, a first hold element S2 that holds the maximum potential Vh, a contraction element S3 whose potential decreases from the maximum potential Vh to a minimum potential Vl, a second hold element S4 that holds the minimum potential Vl, and a second expansion element S5 whose potential increases from the minimum potential Vl to the intermediate potential Vc.

[0032] In a state where the intermediate potential Vc is applied to the driving element PZT, the driving element PZT does not expand or contract. The volume of the pressure chamber 412d when the intermediate potential Vc is applied to the driving element PZT is referred to as the "reference volume."

[0033] When the first expansion element S1 of the drive signal COM is applied to the drive element PZT from a state in which the intermediate potential Vc is applied to the drive element PZT, the drive element PZT contracts in the longitudinal direction. As a result, the volume of the pressure chamber 412d increases (see FIG. 3). When the first hold element S2 of the drive signal COM is applied to the drive element PZT, the contracted state of the drive element PZT is maintained. At this time, the expanded state of the pressure chamber 412d is also maintained. When the contraction element S3 of the drive signal COM is applied to the drive element PZT, the drive element PZT expands from the contracted state. As a result, the volume of the pressure chamber 412d decreases. As a result, the ink pressure in the pressure chamber 412d increases, and an ink droplet is ejected from the nozzle Nz. After that, the second hold element S4 of the drive signal COM is applied to the drive element PZT, and the expanded state of the drive element PZT and the contracted state of the pressure chamber 412d are maintained. When the second expansion component S5 is applied to the driving element PZT, the volume of the pressure chamber 412d returns to the reference volume.

[0034] The time when the first expansion element S1 occurs is called the "first expansion time Pwc1." The time when the first hold element S2 occurs is called the "first hold time Pwh1." The time when the contraction element S3 occurs is called the "contraction time Pwd1." The time when the second hold element S4 occurs is called the "second hold time Pwh2." The time when the second expansion element S5 occurs is called the "second expansion time Pwc2." The first expansion time Pwc1, first hold time Pwh1, contraction time Pwd1, second hold time Pwh2, and second expansion time Pwc2 are parameters that define the shape of the drive waveform W of the drive signal COM.

[0035] A2. Determining the driving waveform: Fig. 5 is a flowchart showing a method for determining the drive waveform of the drive signal applied to the printer 1. The process in Fig. 5 is executed mainly by the CPU 62 of the computer 60 controlling each unit in response to instructions input by the user. The process shown in Fig. 5 determines the drive waveform of the drive signal COM that is applied to the drive element PZT to eject ink from the ink ejection head 41.

[0036] In step S111, the CPU 62 uses the temperature sensor 51 of the printer 1 to obtain the temperature Ta of the environment in which the printer 1 is placed. The environmental conditions defined by the temperature Ta measured in step S111 are also referred to as the "first environmental conditions." The temperature Ta is sent to the computer 60 via the CPU 12 and interface unit 11 of the printer 1.

[0037] In step S121, the CPU 62 selects one of a plurality of predetermined drive waveform candidates Wci, and sends a set of parameters representing the selected drive waveform candidate Wci to the printer 1 (see FIG. 4). The plurality of predetermined drive waveform candidates Wci are candidates for the drive waveform W of the drive signal COM applied to the printer 1. The plurality of sets of parameters representing these drive waveform candidates Wci are stored in advance in the memory 63. The plurality of sets of parameters representing the plurality of drive waveform candidates Wci are shown in FIG. 1 as "waveform parameters 631."

[0038] The CPU 62 instructs the CPU 12 of the printer 1 to execute the following process. The CPU 12 controls the unit control circuit 14 to generate a drive signal based on a set of parameters representing one of the received drive waveform candidates Wci. The CPU 12 then applies the drive signal COM to the drive element PZT of the ink ejection head 41. As a result, ink droplets are ejected from the nozzle Nz.

[0039] In step S131, the CPU 12 causes the CCD camera 55 to capture an image of the ink droplets ejected from the nozzles Nz in response to the drive signal COM. The CPU 12 sends the image data to the computer 60. In step S121, the CPU 62 of the computer 60 instructs the CPU 12 of the printer 1 to execute the above processes of steps S121 and S131.

[0040] In step S131, the CPU 62 calculates the amount of ink ejected Pwa ejected from one nozzle Nz of the ink ejection head 41 by the ejection operation of the driving element PZT based on the image data. The amount of ink ejected is determined by mass. Since the mass is based on the volume and the ink density, the amount of ink ejected may be determined by the volume. The amount of ink ejected is one aspect of the "ejection characteristics". The CPU 62 stores information on this ejection characteristic under an environment of the temperature Ta in the memory 63 in association with information specifying the driving waveform candidate Wci applied to the driving element PZT. The information representing this ejection characteristic is called "first information Ic1". Note that the amount of ink ejected from one nozzle Nz by one ejection operation of the driving element PZT may be used as the amount of ink ejected Pwa.

[0041] The process executed in steps S121 and S131 to acquire first information Ic1 representing the ink ejection characteristics when a certain drive waveform candidate Wci is applied to the drive element PZT at a temperature Ta representing the environmental conditions in which the ink ejection head 41 of the printer 1 is placed is referred to in this specification as the "first acquisition process."

[0042] In step S131b, the CPU 62 determines whether the processes of steps S121 and S131 have been performed for all drive waveform candidates Wci for which the first acquisition process is to be performed. If the processes of steps S121 and S131 have been performed for all drive waveform candidates Wci for which the first acquisition process is to be performed, the process proceeds to step S141. If the processes of steps S121 and S131 have not been performed for all drive waveform candidates Wci for which the first acquisition process is to be performed, the process returns to step S121. Then, from among the multiple drive waveform candidates Wci, one drive waveform candidate Wci for which the processes of steps S121 and S131 have not yet been performed is selected, and the processes of steps S121 and S131 are performed.

[0043] The processes of steps S121 and S131 are repeated to execute the first acquisition process for each of the plurality of predetermined drive waveform candidates Wci. As a result, the first information Ic1 for the plurality of predetermined drive waveform candidates Wci is stored in the memory 63 (see FIG. 1).

[0044] That is, in the first embodiment, the first acquisition process for acquiring the first information Ic1 is executed by applying the driving waveform candidate Wci to the driving element PZT in an environment of air temperature Ta and measuring the ejection characteristics of the ink droplets ejected from the ink ejection head 41 (see S121 and S131 in FIG. 5). The functional unit of the CPU 62 that executes the processes of steps S121 to S131b is shown in FIG. 1 as a first characteristic acquisition unit 622a.

[0045] In step S141 of FIG. 5, the CPU 62 extracts, as a first selected waveform Ws1, a driving waveform candidate Wci in which the ejection characteristics indicated by the first information Ic1 satisfy a predetermined first condition.

[0046] First, the CPU 62 acquires the first deviation information Id1 that indicates the difference between the ejection characteristics indicated by the first information Ic1 and the target ejection characteristics that are ideal ejection characteristics. As a specific example, the CPU 62 calculates a value Dwa as the first deviation information Id1 by the following formula. Dwa = |Pwt - Pwa| (1) Here, Pwt is the ideal discharge amount. Pwa is the ejection amount indicated by the first information Ic1, and is the ejection amount when a driving waveform candidate Wci in the printer 1 is applied.

[0047] When Thwa is a positive number, the CPU 12 extracts, from among the multiple drive waveform candidates Wci, a drive waveform candidate that satisfies Dwa≦Thwa as a first selected waveform Ws1.

[0048] In step S161, the CPU 62 waits until the temperature acquired by the temperature sensor 51 reaches a predetermined temperature. Specifically, the user uses a temperature changing mechanism such as an air conditioner or a thermostatic bath to change the temperature of the environment in which the printer 1 is placed. When the temperature acquired by the temperature sensor 51 becomes a temperature that differs from Ta by more than a predetermined temperature difference, the process proceeds to step S211. Note that the user does not have to operate the temperature changing mechanism, and the computer may automatically operate the temperature changing mechanism in step S161 to change the environmental temperature. Also, in S161, the environmental temperature may be increased or decreased.

[0049] In step S211, the CPU 62 uses the temperature sensor 51 of the printer 1 to obtain the temperature Tb of the environment in which the printer 1 is placed. The environmental conditions defined by the temperature Tb measured in step S211 are also referred to as the "second environmental conditions." The process of step S211 is the same as the process of step S111.

[0050] The processes of steps S221, S231, and S231b are the same as those of steps S121, S131, and S131b, respectively. However, while the processes of steps S121, S131, and S131b are performed in an environment of temperature Ta, the processes of steps S221, S231, and S231b are performed in an environment of temperature Tb. The functional unit of CPU 62 that executes the processes of steps S221 to S231b is shown in FIG. 1 as second characteristic acquisition unit 622b.

[0051] The process executed in steps S221 and S231 to acquire second information Ic2 representing the ink ejection characteristics when a certain drive waveform candidate Wci is applied to the drive element PZT at a temperature Tb representing the environmental conditions in which the ink ejection head 41 of the printer 1 is placed is referred to as the "second acquisition process."

[0052] By repeating the processes of steps S221 and S231, the second acquisition process is executed for each of the plurality of predetermined driving waveform candidates Wci. As a result, the second information Ic2 for the plurality of predetermined driving waveform candidates Wci is stored in the memory 63 (see FIG. 1). The second information Ic2 is information on the ejection characteristics under the environment of the temperature Tb, which is associated with information specifying the driving waveform candidate Wci applied to the driving element PZT.

[0053] That is, in the first embodiment, the second acquisition process for acquiring the second information Ic2 is executed by applying the driving waveform candidate Wci to the driving element PZT in an environment of air temperature Tb and measuring the ejection characteristics of the ink droplets ejected from the ink ejection head 41 (see S221 and S231 in FIG. 5).

[0054] In step S241, the CPU 62 extracts, as a second selected waveform Ws2, a driving waveform candidate Wci in which the ejection characteristics indicated by the second information Ic2 stored in the memory 63 satisfy a predetermined second condition.

[0055] First, the CPU 62 acquires the second deviation information Id2 that indicates the difference between the discharge characteristic indicated by the second information Ic2 and the target discharge characteristic that is the ideal discharge characteristic. As a specific example, the CPU 62 calculates a value Dwb as the second deviation information Id2 by the following formula. Dwb = |Pwt - Pwb| (2) Here, Pwb is the ejection amount indicated by the second information Ic2, and is the ejection amount when a driving waveform candidate Wci in the printer 1 is applied.

[0056] The process of acquiring the first deviation information Id1 and the second deviation information Id2 is also referred to as a "fourth acquisition process."

[0057] When Thwb is a positive number, the CPU 12 extracts, from among the multiple drive waveform candidates Wci, a drive waveform candidate that satisfies Dwb≦Thwb as a second selected waveform Ws2.

[0058] By performing the processes of steps S141 and S241, the driving waveform W is determined based on the first deviation information Id1 and the second deviation information Id2. As a result, a driving waveform candidate in which the ejection characteristic Pwa indicated by the first information Ic1 satisfies the predetermined condition [|Pwt-Pwa|≦Thwa] and the ejection characteristic indicated by the second information Ic2 satisfies the predetermined condition [|Pwt-Pwb|≦Thwb] is determined as the driving waveform W.

[0059] In step S311, the CPU 62 extracts a driving waveform candidate Wci that is included in both the first selected waveform Ws1 and the second selected waveform Ws2 as a third selected waveform Ws3. Note that in the first embodiment, it is assumed that one or more driving waveform candidates Wci that are included in both the first selected waveform Ws1 and the second selected waveform Ws2 are present among the multiple predetermined driving waveform candidates Wci.

[0060] In step S321, the CPU 62 acquires third information Ic3 relating to the difference between the ejection characteristics indicated by the first information Ic1 and the ejection characteristics indicated by the second information Ic2, which are obtained by using the same driving waveform candidate. This process is called the "third acquisition process." The CPU 62 executes the third acquisition process for the driving waveform candidates Wci included in the third selected waveform Ws3.

[0061] As a specific example, the CPU 62 calculates the following evaluation value DP1 as the third information Ic3 for the driving waveform candidate Wci included in the third selected waveform Ws3. DP1 = |Pwb - Pwa| (3)

[0062] In step S331, the CPU 62 determines the drive waveform W based on the evaluation value DP1. Specifically, the CPU 62 determines the drive waveform candidate Wci having the smallest DP1 among the drive waveform candidates Wci included in the third selected waveform Ws3 as the drive waveform W of the drive signal COM to be applied to the drive element PZT of the ink ejection head 41.

[0063] As a result, in step S331, the drive waveform W is determined based on the first information Ic1, the second information Ic2, and at least a part of a plurality of predetermined drive waveform candidates Wci (see steps S141, S241, S321, and S331 in FIG. 5). Then, the drive waveform candidate having the smallest difference between the ejection characteristics indicated by the first information Ic1 and the ejection characteristics indicated by the second information Ic2 is preferentially determined as the drive waveform W (see steps S321 and S331 in FIG. 5). The functional unit of the CPU 62 that executes the processes of steps S311 to S331 is shown in FIG. 1 as a waveform determination unit 624.

[0064] In this manner, it is possible to determine a drive waveform W that is less susceptible to changes in the amount of liquid ejected, which is one aspect of the ejection characteristics, even if the temperature, which defines the environmental conditions in which the printer is placed, changes.

[0065] Furthermore, since steps S141 and S241 are performed prior to step S321, the drive waveform W is determined based on the first deviation information Id1 and the second deviation information Id2 by the processes of steps S141, S241, S321, and S331. Then, a drive waveform candidate in which the difference between the ejection characteristics indicated by the first information Ic1 and the target ejection characteristics is small and the difference between the ejection characteristics indicated by the second information Ic2 and the target ejection characteristics is small is preferentially determined as the drive waveform W.

[0066] As a result, the drive waveform W is determined in consideration of the difference Dwa between the discharge characteristics in an environment of temperature Ta, which is represented by the first deviation information Id1, and the difference Dwb between the discharge characteristics in an environment of temperature Tb, which is represented by the second deviation information Id2, and the ideal discharge characteristics. This makes it possible to prevent a situation in which a drive waveform candidate Wci in which the discharge characteristics in an environment of temperature Ta and the discharge characteristics in an environment of temperature Tb are both significantly different from the ideal discharge characteristics, even though the difference DP1 between the discharge characteristics in an environment of temperature Ta and the discharge characteristics in an environment of temperature Tb is small, is determined as the drive waveform W.

[0067] In the first embodiment, the ejection characteristics under an environment of temperature Ta as the first environmental condition and the ejection characteristics under an environment of air temperature Tb as the second environmental condition are measured using the driving element PZT to which the driving signal COM having the determined driving waveform W is applied (see S131 and S231 in FIG. 5). Therefore, the driving waveform W suitable for the driving element PZT to which the driving signal COM having the determined driving waveform W is applied is determined.

[0068] Furthermore, as long as the method can obtain the same effect as in the first embodiment, a process different from that shown in the flowchart in Fig. 5 may be performed. For example, the extraction of the first selected waveform Ws1 in step S141 and the extraction of the second selected waveform Ws2 in step S241 may be omitted, and the extraction of the first selected waveform Ws1 and the second selected waveform Ws2 may be performed in step S311, and then the extraction of the driving waveform candidate Ws3 may be performed.

[0069] The printing system in this embodiment is also referred to as the "liquid ejection device" (see FIG. 1). The ink ejection head 41 is also referred to as the "liquid ejection head". The unit control circuit 14 is also referred to as the "drive control unit". Step S131 in FIG. 5, which is repeatedly executed, is also referred to as the "first acquisition step". Step S231, which is repeatedly executed, is also referred to as the "second acquisition step". Step S321 is also referred to as the "third acquisition step". Steps S141 and S241 are also referred to as the "fourth acquisition step". Step S331 is also referred to as the "waveform determination step".

[0070] B. Second embodiment: 6 is a block diagram showing printers 1a, 1b and computers 60a, 60b that make up a printing system according to the second embodiment. In the second embodiment, the printing system includes a combination of the computer 60a and the printer 1a, and a combination of the computer 60b and the printer 1b.

[0071] The computer 60a and the computer 60b are connected to each other so that they can communicate with each other. The configuration of the computers 60a and 60b is the same as that of the computer 60 of the first embodiment described with reference to FIG.

[0072] The configuration of the printers 1a and 1b is the same as the printer 1 of the first embodiment described using Figures 1 and 2. The printers 1a and 1b are preferably the same model, but may be different models. The printers 1a and 1b are placed in environments with different temperatures, humidity, and air pressures.

[0073] Fig. 7 is a flowchart showing a method for determining the drive waveform of a drive signal to be applied to the printer 1b in the second embodiment. The method in Fig. 7 corresponds to the method in the first embodiment shown in Fig. 5. For each step in Fig. 7 that corresponds to a step in Fig. 5 of the first embodiment, the first and second digits of the code representing the step are the same as the first and second digits of the corresponding step in Fig. 5.

[0074] In the computer 60a and the printer 1a, the processes of steps S112 to S152 are carried out.

[0075] The processing in steps S112 to S142 is the same as the processing in steps S111 to S141 in FIG. 5, respectively, except that the target printer is the printer 1a.

[0076] In step S152, the CPU 62 of the computer 60a associates the parameters that define the waveform shape and the ink ejection amount Pwa for the drive waveform candidates Wci included in the first selected waveform Ws1 with information that identifies each drive waveform candidate Wci, and transmits them to the computer 60b. The processing in the computer 60a and the printer 1a then ends.

[0077] In the computer 60b and the printer 1b, the processes of steps S212 to S332 are carried out.

[0078] The processing in steps S212 to S242 is the same as the processing in steps S111 to S141 in Fig. 5, except that the target printer is printer 1b. Note that the same waveform parameters 631 are stored in memory 63 of printers 1a and 1b, which are the same model (see S122 and S222 in Fig. 7).

[0079] In step S252, the CPU 62 of the computer 60b receives, from the computer 60b, parameters defining the waveform shape and the ink ejection amount Pwa, which are associated with information specifying the drive waveform candidate Wci.

[0080] In step S312, the CPU 62 of the computer 60b extracts the driving waveform candidates Wci that are included in both the first selected waveform Ws1 and the second selected waveform Ws2 as the third selected waveform Ws3. Note that in the second embodiment, it is assumed that one or more driving waveform candidates Wci that are included in both the first selected waveform Ws1 and the second selected waveform Ws2 are present among the multiple predetermined driving waveform candidates Wci.

[0081] The processes in steps S322 and S332 are the same as those in steps S321 and S331 in FIG. 5, respectively.

[0082] With this aspect as well, as with the first embodiment, it is possible to determine a drive waveform W whose ejection characteristics are less likely to change even if the temperature, which defines the environmental conditions in which the printer is placed, changes.

[0083] Furthermore, in the second embodiment, the ejection characteristics under an environment of temperature Ta and the ejection characteristics under an environment of temperature Tb can be measured in parallel (see S122 to S132b and S222 to S232b in FIG. 7). Therefore, the first information Ic1 and the second information Ic2 can be obtained in a short time (see FIG. 3). Therefore, the drive waveform W used in the printer 1b can be determined in a short time.

[0084] C. Third embodiment: 8 is a block diagram showing the printers 1a and 1b, computers 60a and 60b, and server 70 that make up the printing system of the third embodiment. In the third embodiment, the printing system includes a combination of computer 60a and printer 1a, a combination of computer 60b and printer 1b, and a server 70. Other computer and printer combinations are also connected to the server 70. However, in the third embodiment, the details of the technology will be described with a focus on the combination of computer 60a and printer 1a, the combination of computer 60b and printer 1b, and the server 70.

[0085] The configuration of the computers 60a and 60b is the same as the computer 60 of the first embodiment described using FIG. 1. The configuration of the printers 1a and 1b is the same as the printer 1 of the first embodiment described using FIG. 1 and FIG. 2. The printers 1a and 1b are preferably the same model, but may be different models. The combination of the computer 60a and the printer 1a and the combination of the computer 60b and the printer 1b may be owned by different users. The temperature, humidity, and air pressure of the environments in which the printers 1a and 1b are located are different from each other.

[0086] The server 70 includes an interface unit 71, a CPU 72, and a memory 73. The interface unit 71 transmits and receives data between the server 70 and the computers 60a and 60b. The memory 73 includes an auxiliary memory that stores programs executed by the CPU 72, and a main memory that functions as a work area. The CPU 72 as a processor realizes various functions by loading programs stored in the auxiliary memory into the main memory and executing them.

[0087] FIG. 9 is a flowchart showing a method for determining the drive waveform of the drive signal to be applied to the printers 1a and 1b in the third embodiment. The method in FIG. 9 corresponds to the method in the first embodiment shown in FIG. 5 and the method in the second embodiment shown in FIG. 7. For each step in FIG. 9 that corresponds to the step in FIG. 5 of the first embodiment, the first and second digits of the reference numerals representing the step are the same as the first and second digits of the corresponding step in FIG. 5. For each step in FIG. 9 that corresponds to the step in FIG. 7 of the second embodiment, the first and second digits of the reference numerals representing the step are the same as the first and second digits of the corresponding step in FIG. 7.

[0088] In the computer 60a and the printer 1a, the processes of steps S113 to S163 are carried out.

[0089] The processing in steps S113 to S133b is the same as the processing in steps S112 to S132b in Fig. 7. The processing in step S143 is the same as the processing in step S141 in Fig. 5, except that the target printer is the printer 1a.

[0090] In step S153, the CPU 62 of the computer 60a transmits to the server 70, for the driving waveform candidate Wci included in the first selected waveform Ws1, the parameters that define the shape of the waveform and the ink ejection amount Pwa associated with a combination of information that identifies the type of ink ejection head 41, the temperature Ta, and information that identifies the driving waveform candidate Wci. The information that identifies the type of ink ejection head 41 is information for distinguishing the design of the ink ejection head 41. Liquid ejection heads with the same design have the same information that identifies the type of liquid ejection head. The information that identifies the type of ink ejection head 41 is stored in advance in the memory 13 of the printer 1. In FIG. 1, the information that identifies the type of ink ejection head 41 is indicated as "head ID 132." The CPU 62 of the computer 60a receives the information that identifies the type of ink ejection head 41 from the printer 1a.

[0091] The CPU 72 of the server 70 receives from the computer 60a the parameters that define the shape of the waveform and the ink ejection amount Pwa that are associated with a combination of information that identifies the type of ink ejection head 41, the temperature Ta, and information that identifies the driving waveform candidate Wci included in the first selected waveform Ws1. The CPU 72 of the server 70 then stores the information in the memory 73. The parameters that define the shape of the waveform and the ink ejection amount Pwa for the first selected waveform Ws1 are shown as "first information Ic1s" in FIG. 8. The server 70 also receives first information Ic1s from multiple printers connected to the server 70, and stores the information that identifies the type of ink ejection head 41 and the temperature Ta in association with a combination of information that identifies the driving waveform candidate Wci included in the first selected waveform Ws1.

[0092] In step S163, the CPU 62 of the computer 60a determines the drive waveform W based on the first deviation information Id1. Specifically, the CPU 62 determines the drive waveform candidate Wci with the smallest Dwa, among the drive waveform candidates Wci included in the first selected waveform Ws1, as the drive waveform W of the drive signal COM applied to the drive element PZT of the ink ejection head 41 of the printer 1a (see formula (1) above). This ends the processing in the computer 60a and the printer 1a.

[0093] In the computer 60b and the printer 1b, the processes of steps S213 to S333 are carried out.

[0094] The processing in steps S213 to S233b is the same as the processing in steps S212 to S232b in Fig. 7. The processing in step S243 is the same as the processing in step S241 in Fig. 5, except that the target printer is printer 1b.

[0095] That is, in the third embodiment, the second acquisition process for acquiring the second information is executed by applying a driving waveform candidate Wci to a driving element PZT of another ink ejection head 41 of the same type as the ink ejection head 41 to which the first information Ic1 corresponds, in an environment of air temperature Tb, and measuring the ejection characteristics of the ejected ink droplets (see S223 and S233 in Figure 9).

[0096] In step S253, the CPU 62 of the computer 60b sends a signal requesting the first information Ic1s to the server 70, together with information identifying the type of ink ejection head 41 of the printer 1b. The CPU 62 then receives from the computer 60b the first information Ic1s that matches the type of ink ejection head 41. The first information Ic1s includes parameters that define the shape of the waveform and the ink ejection amount Pwa that are associated with a combination of information identifying the type of ink ejection head 41, the temperature Ta, and information identifying the drive waveform candidate Wci included in the first selected waveform Ws1.

[0097] That is, in the third embodiment, the first acquisition process for acquiring the first information is executed by reading out the first information Ic1s stored in the server 70 in association with the type of ink ejection head 41 and the temperature Ta.

[0098] The processing in steps S313 to S333 is the same as the processing in steps S311 to S331 in FIG. 5, respectively, except that the target printer is the printer 1b.

[0099] With this aspect as well, as with the first embodiment, it is possible to determine a drive waveform W whose ejection characteristics are less likely to change even if the temperature, which defines the environmental conditions in which the printer is placed, changes.

[0100] According to this embodiment, the user of the printer 1a and the computer 60b can obtain the first information Ic1s that represents the ejection characteristics of ink droplets in an environment of temperature Ta (see S253 in FIG. 9) without ejecting liquid using the ink ejection head 41 in an environment of temperature Ta. This makes it easy to determine the drive waveform W from among multiple drive waveform candidates Wci.

[0101] D. Fourth embodiment: 10 is a block diagram showing the printers 1a, 1b and computer 60 that make up the printing system of the fourth embodiment. In the printing system of the fourth embodiment, two printers 1a, 1b are connected to a computer 60.

[0102] The configuration of the computer 60 is the same as the computer 60 of the first embodiment described using FIG. 1. The computer 60 can send different print data to the printers 1a and 1b. The computer 60 can also send the same print data to the printers 1a and 1b. The computer 60 sends parameters that represent the drive waveform of the drive signal to the printers 1a and 1b. In this embodiment, the computer 60 sends the same parameters that represent the drive waveform of the drive signal to the printers 1a and 1b. In other words, the printers 1a and 1b are driven by a drive signal COM that includes the same drive waveform W.

[0103] The configuration of the printers 1a and 1b is the same as the printer 1 of the first embodiment described using Figures 1 and 2. It is preferable that the printers 1a and 1b are the same model. The printers 1a and 1b are placed in environments with different temperatures, humidity, and air pressures.

[0104] FIG. 11 is a flowchart showing a method for determining the drive waveform of the drive signal to be applied to the printers 1a and 1b in the fourth embodiment. The method in FIG. 11 corresponds to the method in the first embodiment shown in FIG. 5, the method in the second embodiment shown in FIG. 7, and the method in the third embodiment shown in FIG. 10. For each step in FIG. 11 that corresponds to the step in FIG. 5 of the first embodiment, the first and second digits of the code representing the step are the same as the first and second digits of the corresponding step in FIG. 5. For each step in FIG. 11 that corresponds to the step in FIG. 7 of the second embodiment, the first and second digits of the code representing the step are the same as the first and second digits of the corresponding step in FIG. 7. For each step in FIG. 11 that corresponds to the step in FIG. 9 of the third embodiment, the first and second digits of the code representing the step are the same as the first and second digits of the corresponding step in FIG. 9.

[0105] The processing in steps S114 to S134b is the same as the processing in steps S111 to S131b in FIG. 5, respectively, except that the target printer is the printer 1a.

[0106] The processing in steps S214 to S234b is the same as the processing in steps S211 to S231b in FIG. 5, respectively, except that the target printer is the printer 1b.

[0107] In step S324, the CPU 62 of the computer 60 executes a third acquisition process for each of a plurality of predetermined driving waveform candidates Wci. That is, the CPU 62 acquires an evaluation value DP4 regarding the difference between the ejection characteristics indicated by the first information Ic1 and the ejection characteristics indicated by the second information Ic2, which are obtained using the same driving waveform candidate, for each driving waveform candidate Wci.

[0108] At this time, the CPU 62 obtains an evaluation value DP4 including the value Dwa of the first deviation information Id1 and the value Dwa of the second deviation information Id2. As a result, the drive waveform W is determined based on the first deviation information Id1 and the second deviation information Id2.

[0109] As a specific example, the CPU 62 calculates the following evaluation value DP4 for each driving waveform candidate Wci. DP4=Dwa 2 +Dwb 2 +DP1 2 =(Pwt-Pwa) 2 +(Pwt-Pwb) 2 +(Pwb-Pwa) 2 (4)

[0110] By performing such a process, the driving waveform W can be determined by taking into consideration the difference between the discharge characteristic Pwa in the environment of the temperature Ta and the discharge characteristic Pwb in the environment of the temperature Tb, which is represented by the third information Ic3, as well as the following points. That is, the driving waveform W can be determined by taking into consideration the difference Dwa between the discharge characteristic Pwa in the environment of the temperature Ta and the ideal discharge characteristic Pwt, which is represented by the first deviation information Id1, and the difference Dwa between the discharge characteristic Pwb in the environment of the temperature Tb and the ideal discharge characteristic Pwt, which is represented by the second deviation information Id2. More specifically, the driving waveform candidate Wci in which the difference Dwa between the discharge characteristic Pwa in the environment of the temperature Ta and the ideal discharge characteristic Pwt and the difference Dwa between the discharge characteristic Pwb in the environment of the temperature Tb and the ideal discharge characteristic Pwt, which is represented by the second deviation information Id2, are small is preferentially determined as the driving waveform W.

[0111] Therefore, for example, the difference between the discharge characteristic Pwa in an environment of temperature Ta and the discharge characteristic Pwb in an environment of temperature Tb is small, but the possibility of a drive waveform candidate in which the discharge characteristic Pwa in an environment of temperature Ta and the discharge characteristic Pwb in an environment of temperature Tb both deviate significantly from the ideal discharge characteristic Pwt being selected as the drive waveform W can be reduced.

[0112] In step S334, the CPU 62 determines the drive waveform W based on the evaluation value DP4. Specifically, the CPU 62 determines, from among the drive waveform candidates Wci, the drive waveform candidate Wci with the smallest DP4 as the drive waveform W of the drive signal COM applied to the drive elements PZT of the ink ejection heads 41 of the printers 1a and 1b.

[0113] As a result, in step S331, the drive waveform W is determined based on the first information Ic1, the second information Ic2, and a plurality of predetermined drive waveform candidates Wci. Then, the drive waveform candidate having the smallest difference between the ejection characteristics indicated by the first information Ic1 and the ejection characteristics indicated by the second information Ic2 is preferentially determined as the drive waveform W (see the third term of the above formula (4)).

[0114] With this aspect as well, as with the first embodiment, it is possible to determine a drive waveform W whose ejection characteristics are less likely to change even if the temperature, which defines the environmental conditions in which the printer is placed, changes.

[0115] E. Fifth embodiment: The configuration of the printing system of the fifth embodiment is the same as that of the printing system of the first embodiment (see FIG. 1). However, in the printing system of the fifth embodiment, a part of the method for determining the drive waveform of the drive signal differs from the method for determining the drive waveform of the drive signal in the first embodiment in that it includes the processes of steps S325, S415, and S425. Other points of the fifth embodiment are the same as those of the first embodiment.

[0116] Fig. 12 is a flowchart showing a method for determining the drive waveform of the drive signal to be applied to the printers 1a and 1b in the fifth embodiment. The method in Fig. 12 corresponds to the method in the first embodiment shown in Fig. 5. For each step in Fig. 12 that corresponds to the step in Fig. 5 of the first embodiment, the first and second digits of the code representing the step are the same as the first and second digits of the corresponding step in Fig. 5.

[0117] The processes in steps S115 to S325 are the same as the processes in steps S111 to S321 in FIG. 5, respectively.

[0118] In step S325b, the CPU 62 of the computer 60 determines whether the drive waveform candidate Wci included in the third selected waveform Ws3 satisfies a predetermined condition. The predetermined condition is a condition that a drive waveform to be applied to the printer 1 must satisfy. If the drive waveform candidate Wci does not satisfy this condition, the drive waveform candidate Wci cannot be used as a drive waveform to be applied to the printer 1. Here, the predetermined condition is that the evaluation value DP1 is equal to or less than a predetermined threshold value Thd. However, other conditions can also be used as the predetermined condition.

[0119] If there is a drive waveform candidate Wci whose evaluation value DP1 is equal to or less than the predetermined threshold value Thd, the process proceeds to step S335. If there is no drive waveform candidate Wci whose evaluation value DP1 is equal to or less than the predetermined threshold value Thd, the process proceeds to step S415. That is, the process of step S415 and the subsequent step S425 are executed when a drive waveform W is not selected from the plurality of predetermined drive waveform candidates Wci.

[0120] In step S335, the CPU 62 determines the drive waveform W based on the evaluation value DP1 (see formula (3) above). Specifically, the CPU 62 determines the drive waveform candidate Wci with the smallest DP1 among the drive waveform candidates Wci included in the third selected waveform Ws3 that satisfy the condition in step S325b as the drive waveform W of the drive signal COM applied to the drive element PZT of the ink ejection head 41 of the printers 1a and 1b. The processing of steps S325b and S335 is executed by the waveform determination unit 624 as a functional unit of the CPU 62.

[0121] In step S415, the CPU 62 judges whether or not the number of times the process has reached step S415 via step S325b has exceeded a predetermined threshold. If the number of times the process has reached step S415 via step S325b has exceeded the predetermined threshold, the process ends. If the number of times the process has reached step S415 via step S325b has not exceeded the predetermined threshold, the process proceeds to step S425.

[0122] In step S425, the CPU 62 generates new drive waveform candidates based on the first information Ic1, the second information Ic2, and at least a part of the plurality of drive waveform candidates Wci determined in advance. Specifically, the CPU 62 uses an optimization method to determine a set of parameters that define one or more new drive waveform candidates Wci based on parameters that define the drive waveform candidates Wci included in the third selected waveform Ws3 and an evaluation value DP1 of the drive waveform candidates Wci. The evaluation value DP1 is information that is determined based on the first information Ic1 and the second information Ic2 (see formula (3) above). The drive waveform candidates Wci included in the third selected waveform Ws3 are at least a part of the plurality of drive waveform candidates Wci determined in advance. As the optimization method, various methods such as Bayesian optimization can be adopted.

[0123] Thereafter, the processing of steps S115 to S325 is executed using the set of parameters that define these drive waveform candidates Wci. As a result, the first acquisition process and the second acquisition process are executed for the new drive waveform candidate Wci (see S125, S135, S225, and S235 in FIG. 12). Then, the drive waveform W is determined based on the first information Ic1 and the second information Ic2 of the new drive waveform candidate Wci and the new drive waveform candidate Wci (see S315 to S335 in FIG. 12).

[0124] With this configuration, it is possible to determine a better drive waveform W without being limited to the plurality of predetermined drive waveform candidates Wci. Note that, in the fifth embodiment as well, in step S425, the new drive waveform candidates Wci are generated based on at least a part of the plurality of predetermined drive waveform candidates Wci, so that the drive waveform W is determined based on the plurality of predetermined drive waveform candidates Wci.

[0125] F. Sixth embodiment: Fig. 13 is a flowchart showing a method for determining the drive waveform of a drive signal in the sixth embodiment. The method for determining the drive waveform of a drive signal in the sixth embodiment includes the methods for determining the drive waveform of a drive signal in the first to fifth embodiments as part of its processing. The hardware configuration of the printing system in the sixth embodiment can be the hardware configuration of the first to fifth embodiments (see Figs. 1, 6, 8 and 10). Here, the hardware configuration of the printing system in the sixth embodiment will be described taking the hardware configuration of the first embodiment as an example.

[0126] In step S510, the CPU 62 of the computer 60 displays on the display 64 a message prompting the user to select a method for determining the drive waveform of the drive signal. Specifically, the user is prompted to decide whether they wish to determine a drive waveform whose print quality is less likely to change even if the environmental conditions in which the printer is placed change, or whether they wish to determine a drive waveform that is optimal for the current environmental conditions in which the printer is placed. The process of determining a drive waveform whose print quality is less likely to change even if the environmental conditions in which the printer is placed change is referred to as the "first determination process." The process of determining a drive waveform that is optimal for the current environmental conditions in which the printer is placed is referred to as the "second determination process."

[0127] Then, the CPU 62 accepts a selection of either the first decision process or the second decision process via the keyboard 65 and the mouse 66. The functional unit of the CPU 62 that performs the function of step S510 is shown in FIG.

[0128] In step S520, the CPU 62 of the computer 60 determines whether or not the first determination process has been selected. If the first determination process has been selected, the process proceeds to step S530. If the second determination process has been selected, the process proceeds to step S540.

[0129] In step S530, the CPU 62 of the computer 60 executes the process of the first embodiment shown in Fig. 5 to determine the drive waveform W. The process of step S530 is realized by the waveform determination unit 624 as a functional unit of the CPU 62 (see Fig. 1).

[0130] In step S540, the CPU 62 of the computer 60 executes the processes of steps S112 to S152 of the second embodiment shown in Figure 7 for the printer 1b to determine the drive waveform W. As a result, the drive waveform W is determined not based on the first information Ic1 related to the environment of the temperature Ta, but based on the second information Ic2 related to the environment of the temperature Tb and a plurality of predetermined drive waveform candidates Wci. The process of step S540 is realized by the waveform determination unit 624 as a functional unit of the CPU 62 (see Figure 1).

[0131] That is, the CPU 62 executes in step S530 or step S540 the determination process selected in step S520 from the first determination process or the second determination process.

[0132] According to this embodiment, when the environmental conditions are unlikely to change or when priority should be given to determining a waveform optimized for the expected environment rather than responding to changes in the environmental conditions, the user can select the second determination process to determine the drive waveform, resulting in the determination of a waveform optimized for the expected environment.

[0133] In addition to this embodiment, Pareto solutions in multi-objective optimization may be presented to the user so that the user can select the balance between the first determination process and the second determination process.

[0134] G. Other embodiments: (1) In the above first embodiment, the following evaluation value DP1 is calculated as third information Ic3 regarding the difference between the ejection characteristics indicated by the first information Ic1 and the ejection characteristics indicated by the second information Ic2 obtained using the same driving waveform candidate (see S321 in Figure 5). DP1 = |Pwb - Pwa| (3)

[0135] In the fourth embodiment, the third information Ic3 is calculated as the following evaluation value DP4 (see S324 in FIG. 11). DP4=Dwa 2 +Dwb 2 +DP 2 =(Pwt-Pwa) 2 +(Pwt-Pwb) 2 +(Pwb-Pwa) 2 (4)

[0136] However, the third information Ic3 may be an evaluation value determined by another method. For example, the following evaluation value DP7 may be adopted as the third information Ic3. Note that the value indicated by the first environmental condition, for example, temperature, is Ta, the value indicated by the second environmental condition, for example, temperature, is Tb, the value of the ejection characteristic indicated by the first information Ic1 is Pa, and the value of the ejection characteristic indicated by the second information Ic2 is Pb. DP7=|Pb-Pa| / |Tb-Ta| ··· (5)

[0137] By determining the evaluation value DP7 in this way, it is possible to determine a drive waveform W that has a small rate of change in the ejection characteristics when the environmental conditions change. Also, because the rate of change is used as the evaluation value DP7, rather than a difference, the drive waveform W determined according to the evaluation value DP7 can eject liquid from the head with a relatively reasonable quality even when the value indicating the environmental condition is not between Ta and Tb.

[0138] Moreover, for example, the following evaluation values ​​DP8 and DP9 can also be adopted as the third information Ic3. DP8=|Pvb-Pva| / |Tb-Ta| ··· (6) DP9={(Pwb-Pwa)^2+(Pvb-Pva)^2}^(1 / 2) / |Tb-Ta| ··· (7)

[0139] (2) In the above embodiment, the ejection characteristic taken into consideration when determining the drive waveform is the ejection amount of liquid ejected from one nozzle of the ink ejection head 41 by the ejection operation of the drive element PZT (see S131, 231 in FIG. 5). As a result, a drive waveform W is determined in which the ejection amount of liquid ejected from one nozzle by the ejection operation of the drive element PZT is less likely to change even if the environmental conditions change. However, the ejection characteristic taken into consideration when determining the drive waveform may be another characteristic.

[0140] For example, the ejection characteristic can be the ejection speed of the liquid ejected from the nozzles of the liquid ejection head. In this manner, it is possible to determine a drive waveform that makes it difficult for the ejection speed of the liquid ejected from the nozzles to change even if the environmental conditions change.

[0141] In such an embodiment, Dva as the first deviation information Id1 is calculated as follows. Dva = |Pvt - Pva| (8) Where: Pvt is the ideal discharge velocity. Pva is the ejection speed when the driving waveform candidate Wci in the printer 1 is applied, as indicated by the first information Ic1.

[0142] Dvb as the second deviation information Id2 is calculated as follows. Dvb = |Pvt - Pvb| (9) Where: Pvb is the ejection speed when the driving waveform candidate Wci in the printer 1 is applied, as indicated by the second information Ic2.

[0143] The evaluation value DPv as the third information Ic3 is calculated as follows. DPv = |Pvb - Pva| (10)

[0144] Furthermore, the ejection characteristics can be the amount of sub-droplets, so-called satellites, ejected from one nozzle of the ink ejection head 41 by the ejection operation of the driving element PZT. In this manner, it is possible to determine a drive waveform that is less susceptible to changes in the amount of sub-droplets ejected from the nozzle even when the environmental conditions change.

[0145] (3) In the above embodiment, the environmental conditions when the ejection characteristics are measured are defined by the temperature of the environment. The second environmental conditions include an environmental temperature Tb that is different from the temperature Ta of the first environmental conditions. As a result, a driving waveform W is determined that is less susceptible to changes in the ejection characteristics even if the environmental temperature changes. However, the environmental conditions when the ejection characteristics are measured can also be defined by other parameters.

[0146] The environmental conditions when the ejection characteristics are measured can be defined by one or more parameters including the humidity of the environment. The second environmental condition can include an environmental humidity that is a value different from the humidity of the first environmental condition. As a result, a driving waveform W in which the ejection characteristics are less likely to change even if the humidity of the environment changes is determined. The humidity of the environment can be acquired by the humidity sensor 52.

[0147] The environmental conditions when the ejection characteristics are measured can be defined by one or more parameters including the atmospheric pressure of the environment. The second environmental conditions can include an atmospheric pressure of the environment that is a value different from the atmospheric pressure of the first environmental conditions. As a result, a driving waveform W is determined in which the ejection characteristics are less likely to change even if the atmospheric pressure of the environment changes. The atmospheric pressure of the environment can be acquired by the atmospheric pressure sensor 53.

[0148] That is, the environmental conditions can be conditions defined by at least one of the environmental temperature, the environmental humidity, and the environmental air pressure.

[0149] (4) In the first embodiment described above, in step S161 of Fig. 5, the user uses the temperature changing mechanism to change the temperature of the environment in which the printer 1 is placed. However, steps S121 to S131b and steps S221 to S231b may be performed in different environments by being performed at different times of the day, such as in the morning and afternoon, or immediately before and during factory operation.

[0150] (5) In the fifth embodiment, in step S325b in Fig. 12, it is determined whether or not the evaluation value DP1 is equal to or less than a predetermined threshold value Thd. However, in step S325b, a determination based on other conditions may be performed. For example, the CPU 62 may display an image of the ink droplet ejection state captured by the CCD camera 55 to the user via the display 64, and prompt the user to determine whether or not the ink droplet ejection state is satisfactory. Then, the CPU 62 may receive the determination result via the keyboard 65 and the mouse 66.

[0151] (6) In the embodiment described above, the CPU 62 of the computer 60 controls the printer 1 and determines the drive waveform. However, the printer may be configured to perform the functions of the computer in each of the embodiments described above. The printer may also be connected to a server without going through the computer 60. The server to which the printer is connected may also be configured to perform the functions of the computer in each of the embodiments described above.

[0152] (7) In the above four embodiments, the ejection characteristics are measured using the ink ejection heads 41 of different printers 1a and 1b (see FIG. 10 and S134 and S234 of FIG. 11). However, the measurement of the ejection characteristics may be performed using different ink ejection heads of a single printer.

[0153] (8) In the first embodiment, among the drive waveform candidates Wci included in the third selected waveform Ws3 selected in advance, the drive waveform candidate Wci with the smallest DP1 is determined as the drive waveform W of the drive signal COM applied to the drive element PZT of the ink ejection head 41. However, for example, constraint conditions may be set for each of the value Dwa of the first deviation information Id1 and the value Dwb of the second deviation information Id2, and the drive waveform W may be determined by performing a constrained single-objective optimization process with the evaluation value DP1 as an objective function.

[0154] (9) In the above embodiment, the ejection characteristics are measured under two environmental conditions, and the drive waveform W of the drive signal COM is determined (see FIGS. 5, 7, 9, 11, and 12). However, the ejection characteristics may be measured under three or more environmental conditions, and the drive waveform of the drive signal may be determined.

[0155] (10) In the above embodiment, the liquid ejection apparatus is a printer that ejects ink. However, the liquid ejection apparatus may be other apparatus, such as an apparatus for manufacturing electronic devices.

[0156] (11) In the above embodiment, the first deviation information Id1 represents the difference between the ejection characteristics indicated by the first information Ic1 and the target ejection characteristics, which are ideal ejection characteristics. However, the first deviation information does not have to represent the difference between the ejection characteristics indicated by the first information and the target ejection characteristics, which are ideal ejection characteristics. In other words, the first deviation information only needs to be information about the difference between the ejection characteristics indicated by the first information and the target ejection characteristics, which are ideal ejection characteristics.

[0157] (12) In the above embodiment, in step S153 of Fig. 9, parameters defining the waveform shape and the ink ejection amount Pwa, which are associated with a combination of information identifying the type of ink ejection head 41, the temperature Ta, and information identifying the driving waveform candidate Wci included in the first selected waveform Ws1, are stored in the memory 73. However, the first information may also be associated with the manufacturing number, individual number, or lot number of the liquid ejection head. In other words, it is sufficient that the first information is associated with the liquid ejection head.

[0158] (13) In the above embodiment, in step S331, the drive waveform W is determined based on the first information Ic1, the second information Ic2, and at least a part of a plurality of predetermined drive waveform candidates Wci (see steps S141, S241, S321, and S331 in FIG. 5). However, the drive waveform may be determined based on the first information and the second information, not based on the plurality of drive waveform candidates.

[0159] (14) In the above embodiment, in step S540, the drive waveform W is determined not based on the first information Ic1, but based on the second information Ic2 related to the environment of the temperature Tb and a plurality of predetermined drive waveform candidates Wci. However, the drive waveform may be determined based on the second information, not based on the first information and the multiple drive waveform candidates.

[0160] H. Further forms: The present disclosure is not limited to the above-mentioned embodiment, and can be realized in various forms without departing from the spirit of the present disclosure. For example, the present disclosure can be realized in the following forms. The technical features in the above-mentioned embodiments corresponding to the technical features in each form described below can be appropriately replaced or combined in order to solve some or all of the problems of the present disclosure, or to achieve some or all of the effects of the present disclosure. Furthermore, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

[0161] (1) According to one aspect of the present disclosure, there is provided a drive waveform determination method for determining a drive waveform of a drive signal to be applied to a drive element of a liquid ejection head in order to eject liquid from the liquid ejection head, the method including: a first acquisition step of executing a first acquisition process to acquire first information on ejection characteristics of liquid when each of a plurality of drive waveform candidates is applied to a drive element under a first environmental condition that is an environmental condition in which the liquid ejection head is placed; a second acquisition step of executing a second acquisition process to acquire second information on the ejection characteristics when each of the plurality of drive waveform candidates is applied to a drive element under a second environmental condition that is an environmental condition in which the liquid ejection head is placed and that is different from the first environmental condition; and a waveform determination step of determining the drive waveform based on the first information and the second information. By adopting such an embodiment, it is possible to determine a drive waveform whose ejection characteristics are less likely to change even if the environmental conditions change.

[0162] (2) In the driving waveform determination method of the above embodiment, a third acquisition process is performed for at least a portion of the multiple driving waveform candidates to acquire third information regarding the difference between the ejection characteristics indicated by the first information and the ejection characteristics indicated by the second information, the third information being obtained using the same driving waveform candidate, and the waveform determination process may be a process of determining the driving waveform based on the third information. By adopting such an embodiment, it is possible to determine a drive waveform that reduces the difference in ejection characteristics when the environmental conditions change.

[0163] (3) In the drive waveform determination method of the above aspect, when the value of the ejection characteristic indicated by the first information is Pa, the value of the ejection characteristic indicated by the second information is Pb, and the value indicated by the third information is DP, It is also possible to have an embodiment where DP=|Pb-Pa|. In this manner, the drive waveform can be determined taking into consideration the difference in ejection characteristics that occurs when environmental conditions change.

[0164] (4) In the drive waveform determination method of the above aspect, when the value indicated by the first environmental condition is Ta, the value indicated by the second environmental condition is Tb, the value of the ejection characteristic indicated by the first information is Pa, the value of the ejection characteristic indicated by the second information is Pb, and the value indicated by the third information is DP, It is also possible to have an embodiment where DP=|Pb-Pa| / |Tb-Ta|. In this manner, the driving waveform W can be determined taking into consideration the rate of change in the ejection characteristics when the environmental conditions change.

[0165] (5) In the drive waveform determination method of the above embodiment, the waveform determination process may be a process of preferentially determining, as the drive waveform, a drive waveform candidate having a small difference between the ejection characteristics indicated by the first information and the ejection characteristics indicated by the second information, based on the third information. By adopting such an embodiment, it is possible to determine a drive waveform whose ejection characteristics are less likely to change even if the environmental conditions change.

[0166] (6) In the drive waveform determination method of the above embodiment, a fourth acquisition process is performed for each of the multiple drive waveform candidates to acquire first deviation information regarding the difference between the ejection characteristics indicated by the first information and target ejection characteristics, which are ideal ejection characteristics, and to acquire second deviation information regarding the difference between the ejection characteristics indicated by the second information and the target ejection characteristics. The waveform determination process can also be a process of determining the drive waveform based on the first deviation information and the second deviation information. In this embodiment, the drive waveform can be determined by taking into consideration the following points in addition to the difference between the ejection characteristics under the first environmental condition and the ejection characteristics under the second environmental condition, which are represented by the third information. That is, the drive waveform can be determined by taking into consideration the difference between the ejection characteristics under the first environmental condition and the ideal ejection characteristics, which are represented by the first deviation information, and the difference between the ejection characteristics under the second environmental condition and the ideal ejection characteristics, which are represented by the second deviation information. Therefore, for example, the difference between the ejection characteristics under the first environmental condition and the ejection characteristics under the second environmental condition is small, but it is possible to reduce the possibility that a drive waveform candidate in which both the ejection characteristics under the first environmental condition and the ejection characteristics under the second environmental condition are significantly deviated from the ideal ejection characteristics is determined as the drive waveform.

[0167] (7) In the driving waveform determination method of the above aspect, when the value of the ejection characteristic indicated by the first information is Pa, the value of the ejection characteristic indicated by the second information is Pb, the value of the target ejection characteristic is Pt, the value indicated by the first deviation information is Da, and the value indicated by the second deviation information is Db, Da=|Pt-Pa| Db = |Pt-Pb| It is also possible to adopt an embodiment in which:

[0168] (8) In the drive waveform determination method of the above embodiment, the waveform determination process may be a process of preferentially determining, based on the first deviation information and the second deviation information, as the drive waveform, a drive waveform candidate in which the difference between the ejection characteristics indicated by the first information and the target ejection characteristics is small, and the difference between the ejection characteristics indicated by the second information and the target ejection characteristics is small.

[0169] (9) In the drive waveform determination method of the above embodiment, the waveform determination process may be a process of preferentially determining, as the drive waveform, a drive waveform candidate whose ejection characteristics indicated by the first information satisfy a first condition and whose ejection characteristics indicated by the second information satisfy a second condition. With this configuration, it is more likely that conditions can be set for the ejection characteristics under the first environmental condition and the ejection characteristics under the second environmental condition, and a drive waveform candidate that satisfies these conditions can be determined as the drive waveform.

[0170] (10) In the drive waveform determination method according to the above aspect, the ejection characteristic may be an ejection amount of liquid ejected from one nozzle of the liquid ejection head by the ejection operation of the drive element. By adopting such an embodiment, it is possible to determine a drive waveform that is less likely to change the amount of liquid ejected from one nozzle by the ejection operation of the drive element, even if the environmental conditions change.

[0171] (11) In the drive waveform determination method according to the above aspect, the ejection characteristic may be an ejection speed of liquid ejected from a nozzle of the liquid ejection head. With this configuration, it is possible to determine a drive waveform that reduces the change in the ejection speed of the liquid ejected from the nozzles even when the environmental conditions change.

[0172] (12) In the drive waveform determination method of the above embodiment, the first acquisition process may include a process of acquiring the first information by reading out the first information stored in a server in correspondence with a liquid ejection head and the first environmental condition, and the second acquisition process may include a process of acquiring the second information by applying a drive waveform candidate to a drive element of a liquid ejection head other than the liquid ejection head under the second environmental condition and measuring the ejection characteristics of the ejected liquid. According to this aspect, the first information representing the ejection characteristics of the liquid can be obtained without ejecting the liquid using the liquid ejection head, and therefore the drive waveform can be easily determined from among a plurality of drive waveform candidates.

[0173] (13) In the drive waveform determination method of the above embodiment, the first acquisition process may include a process of acquiring the first information by applying a drive waveform candidate to the drive element under the first environmental condition and measuring the ejection characteristics of the liquid ejected from the liquid ejection head, and the second acquisition process may include a process of acquiring the second information by applying a drive waveform candidate to the drive element under the second environmental condition and measuring the ejection characteristics of the liquid ejected from the liquid ejection head. In such an embodiment, the ejection characteristics under the first environmental condition and the ejection characteristics under the second environmental condition are measured using a driving element to which a driving signal having the determined driving waveform is applied, and therefore a driving waveform suitable for the driving element to which a driving signal having the determined driving waveform is applied is determined.

[0174] (14) In the drive waveform determination method of the above aspect, the first acquisition process may include a process of acquiring the first information by applying a drive waveform candidate to the drive element under the first environmental condition and measuring the ejection characteristics of liquid ejected from the liquid ejection head, and the second acquisition process may include a process of acquiring the second information by applying a drive waveform candidate to a drive element of another liquid ejection head different from the liquid ejection head under the second environmental condition and measuring the ejection characteristics of liquid ejected from the other liquid ejection head. In this embodiment, the ejection characteristics under the first environmental condition and the ejection characteristics under the second environmental condition can be measured in parallel, making it possible to obtain the first information and the second information in a short period of time.

[0175] (15) In the drive waveform determination method of the above embodiment, the method may include a step that is executed when the drive waveform is not selected from the plurality of drive waveform candidates, and that includes the steps of generating a new drive waveform candidate based on the first information, the second information, and at least a portion of the plurality of drive waveform candidates, executing the first acquisition process and the second acquisition process for the new drive waveform candidate, and determining the drive waveform based on the first information and the second information of the new drive waveform candidate and the new drive waveform candidate. In this manner, the drive waveform can be determined without being limited to a plurality of drive waveform candidates.

[0176] (16) In the drive waveform determination method of the above aspect, the first environmental condition may include a temperature of the environment, and the second environmental condition may include a temperature of the environment that is a value different from the temperature of the first environmental condition. By adopting such an embodiment, it is possible to determine a drive waveform whose ejection characteristics are less likely to change even if the environmental temperature changes.

[0177] (17) In the drive waveform determination method of the above aspect, the first environmental condition may include a humidity of the environment, and the second environmental condition may include a humidity of the environment that is a different value from the humidity of the first environmental condition. By adopting such an embodiment, it is possible to determine a drive waveform whose ejection characteristics are less likely to change even if the humidity of the environment changes.

[0178] (18) In the drive waveform determination method of the above aspect, the first environmental condition may include an air pressure of the environment, and the second environmental condition may include an air pressure of the environment that is a value different from the air pressure of the first environmental condition. By adopting such an embodiment, it is possible to determine a drive waveform whose ejection characteristics are less likely to change even if the atmospheric pressure of the environment changes.

[0179] (19) According to another aspect of the present disclosure, there is provided a computer program for causing a computer to execute the drive waveform determination method according to any one of Application Examples 1 to 18.

[0180] (20) According to another aspect of the present disclosure, there is provided a liquid ejection device comprising: a liquid ejection head including a driving element that is driven by application of a driving signal and ejects liquid by driving the driving element; a drive control unit that controls the liquid ejection head; a first characteristic acquisition unit capable of executing a first acquisition process to acquire first information representing ejection characteristics of liquid when each of a plurality of driving waveform candidates is applied to the driving element under first environmental conditions that are environmental conditions in which the liquid ejection head is placed; a second characteristic acquisition unit capable of executing a second acquisition process to acquire second information representing the ejection characteristics when each of the plurality of driving waveform candidates is applied to the driving element under second environmental conditions that are environmental conditions in which the liquid ejection head is placed and that are different from the first environmental conditions; and a waveform determination unit capable of executing a first determination process to determine a drive waveform of a drive signal to be applied to the driving element based on the first information and the second information.

[0181] (21) In the liquid ejection device of the above aspect, the waveform determination unit can execute a second determination process to determine the drive waveform based on the second information rather than on the first information, and the liquid ejection device can also be configured to include a receiving unit that receives a selection of either the first determination process or the second determination process, and the waveform determination unit can execute the selected determination process from the first determination process or the second determination process. In this manner, when the environmental conditions are unlikely to change or when priority should be given to determining a waveform optimized for the expected environment rather than to responding to changes in the environmental conditions, the user can select the second determination process and have the driving waveform determination device execute it, resulting in the determination of a waveform optimized for the expected environment.

[0182] The present disclosure can be realized in various forms other than the drive waveform determination method, the liquid ejection device, and the computer program. For example, the present disclosure can be realized in the form of a drive waveform determination device, a drive waveform determination assist device, a control method for those devices, a computer program for realizing that control method, a non-transient recording medium on which that computer program is recorded, etc. In addition, although the printer 1 has been described in each embodiment, a printer does not have to be used in the liquid ejection device, and so-called experimental equipment or evaluation equipment may be used instead as long as it has a function of ejecting liquid. [Explanation of symbols]

[0183] 1...printer, 1a...printer, 1b...printer, 10...controller, 11...interface section, 12...CPU, 13...memory, 14...unit control circuit, 15...drive signal generating circuit, 20...transport unit, 30...carriage unit, 31...carriage, 40...head unit, 41...ink ejection head, 50...detector group, 51...temperature sensor, 52...humidity sensor, 53...atmospheric pressure sensor, 55...CCD camera, 60...computer, 60a...computer, 60b...computer, 61...interface section, 62...CPU, 63...memory, 64...display, 65...keyboard, 66...mouse, 70...server, 71...interface section, 72...CPU, 73...memory, 132...head ID, 411...case, 412...flow path unit, 412a...flow path forming plate, 412b...elastic plate, 412c...nozzle plate, 412d...pressure chamber, 412e...nozzle communication port, 412f... common ink chamber, 412g... ink supply path, 412h... island portion, 412i... elastic membrane, 622a... first characteristic acquisition portion, 622b... second characteristic acquisition portion, 624... waveform determination portion, 626... reception portion, 631... waveform parameter, Dm... main scanning direction, Ds... sub-scanning direction, HC... head control portion, Ic1... first information, Ic1s... first information, Ic2... second information, Ic3... third information, Id1... first deviation information, Id2... second deviation information, Nz... Nozzle, PM...printing medium, PZT...driving element, Pwc1...first expansion time, Pwc2...second expansion time, Pwd1...contraction time, Pwh1...first hold time, Pwh2...second hold time, S1...first expansion element, S2...first hold element, S3...contraction element, S4...second hold element, S5...second expansion element, Vc...intermediate potential, Vh...highest potential, Vl...lowest potential, W...driving waveform, Ws1...first selected waveform, Ws2...second selected waveform, Ws3...third selected waveform

Claims

1. 1. A method for determining a drive waveform of a drive signal applied to a drive element of a liquid ejection head in order to eject liquid from the liquid ejection head, comprising the steps of: a first acquisition step of executing a first acquisition process to acquire first information on liquid ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under a first environmental condition that is an environmental condition in which the liquid ejection head is placed; a second acquisition step of executing a second acquisition process to acquire second information on the ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under second environmental conditions that are different from the first environmental conditions and are the environmental conditions in which the liquid ejection head is placed; A drive waveform determination method comprising: a waveform determination process for determining one drive waveform to be used in common under both the first environmental condition and the second environmental condition based on the first information and the second information.

2. 1. A method for determining a drive waveform of a drive signal applied to a drive element of a liquid ejection head in order to eject liquid from the liquid ejection head, comprising the steps of: a first acquisition step of executing a first acquisition process to acquire first information on liquid ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under a first environmental condition that is an environmental condition in which the liquid ejection head is placed; a second acquisition step of executing a second acquisition process to acquire second information on the ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under second environmental conditions that are different from the first environmental conditions and are the environmental conditions in which the liquid ejection head is placed; a waveform determination step of determining the drive waveform based on the first information and the second information; a third acquisition step of acquiring third information relating to a difference between the ejection characteristics indicated by the first information and the ejection characteristics indicated by the second information, the third acquisition step being performed for at least a part of the plurality of driving waveform candidates, the third acquisition step acquiring third information relating to a difference between the ejection characteristics indicated by the first information and the ejection characteristics indicated by the second information, the third acquisition step being performed for at least a part of the plurality of driving waveform candidates, The drive waveform determination method, wherein the waveform determination step is a step of determining the drive waveform based on the third information.

3. 3. The drive waveform determination method according to claim 2, When the value of the ejection characteristic indicated by the first information is Pa, the value of the ejection characteristic indicated by the second information is Pb, and the value indicated by the third information is DP, A method for determining a drive waveform, in which DP=|Pb-Pa|.

4. 3. The drive waveform determination method according to claim 2, When the value indicated by the first environmental condition is Ta, the value indicated by the second environmental condition is Tb, the value of the ejection characteristic indicated by the first information is Pa, the value of the ejection characteristic indicated by the second information is Pb, and the value indicated by the third information is DP, A method for determining a drive waveform, in which DP=|Pb-Pa| / |Tb-Ta|.

5. 5. The drive waveform determination method according to claim 2, further comprising the steps of: The waveform determination process is a process of preferentially determining, based on the third information, as the drive waveform, a drive waveform candidate that has a small difference between the ejection characteristics indicated by the first information and the ejection characteristics indicated by the second information.

6. 2. The drive waveform determination method according to claim 1, a fourth acquisition step for acquiring first deviation information on a difference between the ejection characteristics indicated by the first information and a target ejection characteristic which is an ideal ejection characteristic, and acquiring second deviation information on a difference between the ejection characteristics indicated by the second information and the target ejection characteristic for each of the plurality of drive waveform candidates; The drive waveform determination method, wherein the waveform determination step is a step of determining the drive waveform based on the first deviation information and the second deviation information.

7. 7. A method for determining a drive waveform according to claim 6, comprising: When the value of the ejection characteristic indicated by the first information is Pa, the value of the ejection characteristic indicated by the second information is Pb, the value of the target ejection characteristic is Pt, the value indicated by the first deviation information is Da, and the value indicated by the second deviation information is Db, Da = |Pt-Pa| Db=|Pt−Pb| A method for determining a drive waveform.

8. 8. The drive waveform determination method according to claim 6, further comprising the steps of: The waveform determination process is a process of preferentially determining, based on the first deviation information and the second deviation information, as the drive waveform, a drive waveform candidate in which the difference between the ejection characteristics indicated by the first information and the target ejection characteristics is small, and the difference between the ejection characteristics indicated by the second information and the target ejection characteristics is small.

9. 9. A drive waveform determination method according to claim 1, comprising: The waveform determination process is a process of preferentially determining, as the drive waveform, a drive waveform candidate whose ejection characteristics indicated by the first information satisfy a first condition and whose ejection characteristics indicated by the second information satisfy a second condition.

10. 10. A drive waveform determination method according to claim 1 , comprising: The drive waveform determination method, wherein the ejection characteristic is an ejection amount of liquid ejected from one nozzle of the liquid ejection head by an ejection operation of the drive element.

11. 1. A method for determining a drive waveform of a drive signal applied to a drive element of a liquid ejection head in order to eject liquid from the liquid ejection head, comprising the steps of: a first acquisition step of executing a first acquisition process to acquire first information on liquid ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under a first environmental condition that is an environmental condition in which the liquid ejection head is placed; a second acquisition step of executing a second acquisition process to acquire second information on the ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under second environmental conditions that are different from the first environmental conditions and are the environmental conditions in which the liquid ejection head is placed; a waveform determination step of determining the drive waveform based on the first information and the second information, The drive waveform determining method, wherein the ejection characteristic is an ejection speed of liquid ejected from a nozzle of the liquid ejection head.

12. 1. A method for determining a drive waveform of a drive signal applied to a drive element of a liquid ejection head in order to eject liquid from the liquid ejection head, comprising the steps of: a first acquisition step of executing a first acquisition process to acquire first information on liquid ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under a first environmental condition that is an environmental condition in which the liquid ejection head is placed; a second acquisition step of executing a second acquisition process to acquire second information on the ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under second environmental conditions that are different from the first environmental conditions and are the environmental conditions in which the liquid ejection head is placed; a waveform determination step of determining the drive waveform based on the first information and the second information, the first acquisition process includes a process of acquiring the first information by reading out the first information stored in a server in association with the liquid ejection head and the first environmental condition, A driving waveform determination method, wherein the second acquisition process includes a process of acquiring the second information by applying a driving waveform candidate to a driving element of another liquid ejection head different from the liquid ejection head under the second environmental conditions and measuring the ejection characteristics of the ejected liquid.

13. 12. A drive waveform determination method according to claim 1, comprising: the first acquisition process includes a process of acquiring the first information by applying a drive waveform candidate to the drive element under the first environmental condition and measuring ejection characteristics of liquid ejected from the liquid ejection head; A drive waveform determination method, wherein the second acquisition process includes a process of acquiring the second information by applying a drive waveform candidate to the drive element under the second environmental conditions and measuring the ejection characteristics of the liquid ejected from the liquid ejection head.

14. 1. A method for determining a drive waveform of a drive signal applied to a drive element of a liquid ejection head in order to eject liquid from the liquid ejection head, comprising the steps of: a first acquisition step of executing a first acquisition process to acquire first information on liquid ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under a first environmental condition that is an environmental condition in which the liquid ejection head is placed; a second acquisition step of executing a second acquisition process to acquire second information on the ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under second environmental conditions that are different from the first environmental conditions and are the environmental conditions in which the liquid ejection head is placed; a waveform determination step of determining the drive waveform based on the first information and the second information, the first acquisition process includes a process of acquiring the first information by applying a drive waveform candidate to the drive element under the first environmental condition and measuring ejection characteristics of liquid ejected from the liquid ejection head; A drive waveform determination method, wherein the second acquisition process includes a process of acquiring the second information by applying a drive waveform candidate to a drive element of another liquid ejection head different from the liquid ejection head under the second environmental conditions and measuring the ejection characteristics of liquid ejected from the other liquid ejection head.

15. 1. A method for determining a drive waveform of a drive signal applied to a drive element of a liquid ejection head in order to eject liquid from the liquid ejection head, comprising the steps of: a first acquisition step of executing a first acquisition process to acquire first information on liquid ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under a first environmental condition that is an environmental condition in which the liquid ejection head is placed; a second acquisition step of executing a second acquisition process to acquire second information on the ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under second environmental conditions that are different from the first environmental conditions and are the environmental conditions in which the liquid ejection head is placed; a waveform determination step of determining the drive waveform based on the first information and the second information, A step that is executed when the drive waveform is not selected from the plurality of drive waveform candidates, generating a new drive waveform candidate based on the first information, the second information, and at least a part of the plurality of drive waveform candidates; Executing the first acquisition process and the second acquisition process for the new drive waveform candidate; determining the drive waveform based on the first information and the second information of the new drive waveform candidate and the new drive waveform candidate; A drive waveform determining method comprising the steps of:

16. 16. A drive waveform determination method according to claim 1, comprising: the first environmental condition includes a temperature of the environment; The drive waveform determination method, wherein the second environmental condition includes a temperature of the environment that is a value different from the temperature of the first environmental condition.

17. 17. A drive waveform determination method according to claim 1, comprising: the first environmental condition includes humidity of the environment; The method of determining a drive waveform, wherein the second environmental condition includes a humidity of the environment that is a different value from the humidity of the first environmental condition.

18. 18. A drive waveform determination method according to claim 1, comprising: the first environmental condition includes an air pressure of the environment; The method of determining a drive waveform, wherein the second environmental condition includes an air pressure of the environment that is a value different from the air pressure of the first environmental condition.

19. A computer program for causing a computer to execute the drive waveform determination method according to any one of claims 1 to 18.

20. A liquid ejection device, a liquid ejection head including a drive element that is driven by an applied drive signal, and ejects liquid by driving the drive element; A drive control unit that controls the liquid ejection head; a first characteristic acquisition unit capable of executing a first acquisition process to acquire first information representing liquid ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under a first environmental condition which is an environmental condition in which the liquid ejection head is placed; a second characteristic acquisition unit capable of executing a second acquisition process to acquire second information representing the ejection characteristics when each of the plurality of drive waveform candidates is applied to a drive element under second environmental conditions that are different from the first environmental conditions and are the environmental conditions in which the liquid ejection head is placed; A liquid ejection device comprising: a waveform determination unit capable of executing a first determination process to determine a single drive waveform to be used in common under both the first environmental condition and the second environmental condition, the drive waveform being a drive signal to be applied to the drive element based on the first information and the second information.

21. A liquid ejection device, a liquid ejection head including a drive element that is driven by an applied drive signal, and ejects liquid by driving the drive element; A drive control unit that controls the liquid ejection head; a first characteristic acquisition unit capable of executing a first acquisition process to acquire first information representing liquid ejection characteristics when each of a plurality of drive waveform candidates is applied to a drive element under a first environmental condition which is an environmental condition in which the liquid ejection head is placed; a second characteristic acquisition unit capable of executing a second acquisition process to acquire second information representing the ejection characteristics when each of the plurality of drive waveform candidates is applied to a drive element under second environmental conditions that are different from the first environmental conditions and are the environmental conditions in which the liquid ejection head is placed; a waveform determination unit capable of executing a first determination process to determine a drive waveform of a drive signal to be applied to the drive element based on the first information and the second information, the waveform determination unit may execute a second determination process to determine the drive waveform based on the second information, not based on the first information; the liquid ejection device includes a reception unit configured to receive a selection of either the first determination process or the second determination process; The waveform determination unit executes a determination process selected from the first determination process and the second determination process.

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