Liquid ejection head driving device, liquid ejection head driving system, liquid ejection device, liquid ejection head driving method, and program

Abstract

To provide a liquid ejection head driving device, a liquid ejection head driving system, a liquid ejection device, a liquid ejection head driving method, and a program, each enabling improvement of printing quality.SOLUTION: A head driving device is provided, driving a plurality of nozzles that eject liquid according to an input driving signal and comprising: a driving signal output portion that generates the driving signal on the basis of voltage information which is applied to piezoelectric elements of the nozzles and that outputs the driving signal to a head; a voltage information acquisition portion that acquires appropriate voltage information, on the basis of droplet velocity information obtained by droplet velocity measuring means measuring the ejection velocity of droplets ejected from the head and the voltage information, such that the ejection velocity falls within a predetermined range; a storage portion that stores the appropriate voltage information in association with identification information of the nozzles and drive frequencies of the nozzles; and a control portion that acquires, from the storage portion, the appropriate voltage information corresponding to the identification information and the drive frequencies, and causes the driving signal output portion to output the driving signal on the basis of the appropriate voltage information.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a liquid ejection head driving device, a liquid ejection head driving system, a liquid ejection device, a liquid ejection head driving method, and a program.

Background Art

[0002] In a droplet ejection device, there is a characteristic that the ejection speed of droplets from a nozzle changes depending on the driving frequency. In order to suppress this change in ejection speed, techniques have been developed to change the driving voltage and driving waveform of the head according to the driving frequency.

[0003] Further, an inkjet head of a droplet ejection device has a plurality of nozzles mounted in one row, and has a characteristic that the ejection speed is different between the central portion and the end portion of the row. Conventionally, the design has been such that the difference in ejection speed between the central portion and the end portion of the row does not cause a problem. However, as the driving of the head has become higher in frequency and the frequency band of the driving of the head has become wider, it has become difficult to suppress the difference in ejection speed between the central portion and the end portion of the row to a level where it does not cause a problem over the entire band. Patent Document 1 discloses a technique in which two types of driving waveforms of the head are provided within the row of nozzles so that the difference in ejection speed between the central portion and the end portion of the row can be corrected.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique described in Patent Document 1, since the driving frequency for changing the driving waveform and the voltage value for determining the wave height value are input in advance, it is difficult to cover variations between heads, environmental temperature in a printing device, and variations in the type of ink used.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a liquid ejection head driving device, a liquid ejection head driving system, a liquid ejection device, a liquid ejection head driving method, and a program capable of improving printing quality.

Means for Solving the Problems

[0006] In order to solve the above-described problems and achieve the object, the present invention is a liquid ejection head driving device that drives a liquid ejection head having a plurality of nozzles that eject liquid in response to an input drive signal, and generates the drive signal based on voltage information related to the voltage applied to the piezoelectric element of the nozzle, and outputs the drive signal to the liquid ejection head; a drive signal output unit; a voltage information acquisition unit that acquires appropriate voltage information in which the ejection speed falls within a predetermined range based on the droplet speed information acquired from droplet speed measurement means for measuring the ejection speed of droplets ejected from the liquid ejection head and the voltage information; a storage unit that stores the appropriate voltage information in association with the identification information of the nozzle and the drive frequency of the nozzle; and a control unit that acquires the appropriate voltage information corresponding to the identification information and the drive frequency from the storage unit and causes the drive signal output unit to output the drive signal based on the appropriate voltage information.

Effect of the Invention

[0007] According to the present invention, there is an effect that print quality can be improved.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of a liquid ejection head driving device, a liquid ejection head driving system, a liquid ejection device, a liquid ejection head driving method, and a program will be described in detail with reference to the accompanying drawings.

[0010] FIG. 1 is a diagram for explaining an example of the characteristics of the drive frequency of the nozzles at the end of the liquid ejection head included in the liquid ejection device according to the present embodiment. In FIG. 1, the vertical axis represents the change rate of the ejection speed (ejection speed change rate) of the liquid ejection head (for example, an inkjet head), and the horizontal axis represents the drive frequency of the nozzles included in the liquid ejection head. The example shown in FIG. 1 is the characteristic of the drive frequency of the nozzles with a maximum drive frequency of 40 kHz. At 40 kHz or less, the ejection speed of the droplets from the nozzles changes depending on the drive frequency.

[0011] FIG. 2 is a diagram for explaining an example of the characteristics of the driving frequency in driving the nozzles of all channels of the liquid ejection head included in the liquid ejection apparatus according to the present embodiment. In FIG. 2, the horizontal axis represents the driving frequency, and the vertical axis represents the discharge speed change rate. Each plot in FIG. 2 shows the characteristics of the driving frequency of the nozzles located at the center of a plurality of nozzle rows included in a plurality of liquid ejection heads. More specifically, in FIG. 2, an example is shown in which the characteristics of the driving frequency of the nozzles at the center of each row are shown for five liquid ejection heads having four nozzle rows. In the liquid ejection head of the example shown in FIG. 2, the maximum driving frequency is 40 kHz, but the discharge speed particularly tends to decrease when the driving frequency is 12 kHz or less. Further, the amount of decrease varies for each liquid ejection head and for each row of the liquid ejection head. When compared with the characteristics of the driving frequency of the end nozzles of the liquid ejection head shown in FIG. 1, the characteristics of the driving frequency of the nozzles at the center shown in FIG. 2 show that the discharge speed of the droplets changes according to the driving frequency when the driving frequency is 12 kHz or less. This difference in the discharge speed can be corrected by changing the driving voltage or driving waveform of the nozzle according to the driving frequency. However, variations occur in the driving frequency that decreases depending on the environmental temperature in the printing apparatus (an example of the liquid ejection apparatus) and the type of ink used for each liquid ejection head. Also, variations occur in the decreasing discharge speed.

[0012] FIG. 3 is a diagram for explaining an example of the characteristics of the discharge speed within one row of the nozzles of the liquid ejection head included in the liquid ejection apparatus according to the present embodiment. In FIG. 3, the horizontal axis represents the channels of the nozzles within the row, and the vertical axis represents the discharge speed of the droplets. Also, in FIG. 3, the broken line represents the characteristics of the discharge speed when the driving frequency is 40 kHz, and the solid line represents the characteristics of the discharge speed during low-frequency driving and when the driving voltage or driving waveform is corrected so that the discharge speed of the nozzles at the ends of the liquid ejection head is the same as the characteristics when the driving frequency is 40 kHz.

[0013] In the case of low-frequency driving (for example, when the driving frequency is 12 kHz or less as shown in FIG. 2), the decrease in the ejection speed of the nozzles in the central part of the liquid ejection head is larger compared to when the driving frequency is 40 kHz. This decrease varies depending on the driving frequency. It is necessary to suppress the decrease in the central part within a range that does not cause problems in print quality across the entire driving frequency band used for printing. In this example, by switching the driving waveform so that the ejection speed in the central part of the liquid ejection head becomes faster, the difference in ejection speed between the end part and the central part of the liquid ejection head can be reduced. However, for each liquid ejection head, variations occur in the driving frequency that decreases due to the environmental temperature in the printing apparatus and the type of ink used. Also, variations occur in the decreasing ejection speed.

[0014] FIG. 4 is a diagram showing an example of the configuration of an inkjet head control device having a Vj adjustment control circuit according to the present embodiment. Here, "Vj" in the Vj adjustment control circuit is a term meaning the speed of the droplets ejected by the liquid ejection head. FIG. 5 is a diagram showing an example of the configuration of an inkjet head included in the liquid ejection apparatus according to the present embodiment. The inkjet head control device 2 is an example of a liquid ejection head driving device that drives the first and second droplet ejection devices 13 and 14 (for example, inkjet heads). The first and second droplet ejection devices 13 and 14 are examples of liquid ejection heads having a plurality of nozzles that eject a liquid (such as droplets of ink) in response to an input driving signal. Specifically, the inkjet head control device 2 includes an operation mode switching circuit 3, a Vj adjustment control circuit 4, a memory 5, a droplet observation device 6, a first driving waveform generation circuit 7, a second driving waveform generation circuit 8, waveform selection control circuits 9 and 12, a third driving waveform generation circuit 10, and a fourth driving waveform generation circuit 11.

[0015] The operation mode switching circuit 3 switches the operation mode of the inkjet head control device 2 to the normal drive mode or the appropriate Vj correction mode. The first drive waveform generation circuit 7 and the second drive waveform generation circuit 8 generate drive signals (drive waveforms) based on voltage information related to the voltage (voltage value) applied to the piezoelectric elements of the nozzles, and are an example of a drive signal output unit that outputs the drive waveforms to the first droplet ejection device 13. The third drive waveform generation circuit 10 and the fourth drive waveform generation circuit 11 generate drive signals (drive waveforms) based on the voltage information, and are an example of a drive signal output unit that outputs the drive waveforms to the second droplet ejection device 14.

[0016] The Vj adjustment control circuit 4 is an example of a voltage information acquisition unit that acquires appropriate voltage information (appropriate voltage value) based on the droplet velocity information indicating the ejection velocity acquired from the droplet observation device 6 (an example of droplet velocity measurement means) that measures the ejection velocity of the ink ejected from the first and second droplet ejection devices 13 and 14, and the voltage information. Here, the Vj adjustment control circuit 4 may acquire appropriate voltage information for each nozzle of the first and second droplet ejection devices 13 and 14, or may acquire appropriate voltage information for each block obtained by dividing a plurality of nozzles of the first and second droplet ejection devices 13 and 14 (for example, three blocks at one end, the center, and the other end of the inkjet head).

[0017] Further, when the inkjet head control device 2 transitions from the normal drive mode to the appropriate Vj correction mode (an example of a correction mode), the Vj adjustment control circuit 4 may acquire appropriate voltage information based on the droplet velocity information and the voltage information. Also, the Vj adjustment control circuit 4 may acquire appropriate voltage information for each inkjet head. Further, the Vj adjustment control circuit 4 may acquire appropriate voltage information for each temperature around the inkjet head. Further, the Vj adjustment control circuit 4 may acquire appropriate voltage information for each type of ink ejected from the inkjet head. Here, the type of ink may be set based on information set by the user or the like.

[0018] The memory 5 is an example of a storage unit that stores appropriate voltage information in association with the identification information of the nozzles (such as ch numbers) and the driving frequencies of the nozzles. Further, the Vj adjustment control circuit 4 acquires, from the memory 5, the appropriate voltage information corresponding to the identification information of the nozzles for adjusting the ink ejection speed and the driving frequencies, and based on the appropriate voltage information, controls the waveform selection control circuits 9 and 12 to output driving waveforms to the first to fourth driving waveform generation circuits 7, 8, 10, and 11. This is an example of a control unit. As a result, it is possible to reduce the difference in ejection speed between the central part and the end part of the nozzle row, including variations in the driving frequency of the nozzles of the inkjet head, variations between inkjet heads, the ambient temperature in a liquid ejection device such as a printing apparatus, and variations in the type of liquid such as the ink used, so that the print quality can be improved. The waveform selection control circuits 9 and 12 are controlled by the Vj adjustment control circuit 4 and select the driving waveforms to be output to the first and second droplet ejection devices 13 and 14.

[0019] The droplet observation device 6 is an example of a droplet speed measuring means and has a camera for measuring droplets. The camera is movable with respect to the first and second droplet ejection devices 13 and 14 and is provided so as to be able to measure the ink ejection speed for each nozzle. In the present embodiment, the droplet observation device 6 is provided inside the inkjet head control device 2, but may be provided outside the inkjet head control device 2 as long as it can communicate with the inkjet head control device 2 by wireless communication or the like.

[0020] Two types of driving waveforms (first driving waveform, second driving waveform) are generated by each of the first driving waveform generation circuit 7, the second driving waveform generation circuit 8, the third driving waveform generation circuit 10, and the fourth driving waveform generation circuit 11, and one of the driving waveforms is selected by the analog switch ASW to drive the piezoelectric elements (for example, the piezoelectric elements 36 and 39 shown in FIG. 5) of the first and second droplet ejection devices 13 and 14 (for example, inkjet heads).

[0021] In the following description, when the first drive waveform generation circuit 7, the second drive waveform generation circuit 8, and the third drive waveform generation circuit 10 and the fourth drive waveform generation circuit 11 are not distinguished, they are referred to as the drive waveform generation circuit. Also, in FIG. 5, the droplet ejection device 30 represents a detailed configuration example of each of the first droplet ejection device 13 and the second droplet ejection device 14 shown in FIG. 4. The drive waveform generation circuit 31 corresponds to the first drive waveform generation circuit 7 or the third drive waveform generation circuit 10 shown in FIG. 4, and the drive waveform generation circuit 32 corresponds to the second drive waveform generation circuit 8 or the fourth drive waveform generation circuit 11 shown in FIG. 4.

[0022] However, if three or four or more drive waveform generation circuits and analog switches ASW are prepared instead of two for each nozzle 1ch of the inkjet head, more types of drive waveforms can be applied to each piezoelectric element instead of two types. In this embodiment, the minimum configuration of two drive waveform generation circuits and analog switches ASW will be described.

[0023] When the Vj adjustment control circuit 4, the first waveform selection control circuit 9, the second waveform selection control circuit 12, and the droplet observation device (for example, a camera) 6 enter the appropriate Vj correction mode in response to a mode switching instruction from the host control device 1, for each inkjet head, each channel, and each drive frequency, a voltage value that satisfies the ejection of droplets is obtained so as to suppress the variation in the ejection speed within a specified range and suppress the decrease in the ejection speed at the center of the inkjet head. Then, the Vj adjustment control circuit 4 stores a voltage value map including the obtained voltage value in the memory 5.

[0024] Also, when the Vj adjustment control circuit 4 enters the normal drive mode according to the mode switching instruction from the host control device 1, it accesses the memory 5, reads out the voltage value map stored in the appropriate Vj correction mode, and gives instructions to the first to fourth drive waveform generation circuits 7, 8, 10, and 11 with appropriate voltage values to eject droplets with the appropriate voltage values. Having two drive waveform generation circuits for each head is to enable the first drive waveform generation circuit 7 to generate and output a drive waveform at a drive frequency without a decrease in the ejection speed, and the second drive waveform generation circuit 8 to generate and output a correction waveform (a drive waveform with an increased voltage value) at a drive frequency with a decreased ejection speed. By performing the generation and output of this correction waveform, it is possible to reduce the decrease in the ejection speed at the center when the drive frequency that decreases due to the environmental temperature in the printing apparatus and the type of ink used changes for each inkjet head, and improve the print quality.

[0025] Using FIGS. 4, 6 to 8, an example of the flow of the measurement process of the ejection speed of droplets in the inkjet head control device according to the present embodiment will be described. FIG. 6 is a diagram for explaining an example of the measurement process of the ejection speed of droplets in the inkjet head control device according to the present embodiment. FIGS. 7 and 8 are flowcharts showing an example of the flow of the measurement process of the ejection speed of droplets in the inkjet head control device according to the present embodiment.

[0026] The Vj adjustment control circuit 4 transitions to the appropriate Vj correction mode according to the mode switching instruction from the host control device 1. First, the host control device 1 instructs the Vj adjustment control circuit 4 of the measurement conditions. Here, the measurement conditions may be information such as the head No. of the inkjet head for which the ejection speed is to be measured, the drive frequency (pinpoint drive frequency or range of drive frequencies), the type of ink, and the head temperature. In the present embodiment, the measurement conditions include a head No. of 0002, drive frequencies (2 to 40 kHz, every 1 kHz), the type of ink (for example, fixed), the head temperature (for example, fixed at 25° C.), and the like.

[0027] In step S51, measurement conditions are loaded from the host controller 1 to the Vj adjustment control circuit 40. In step S52, the Vj adjustment control circuit 4 determines that the inkjet head for measuring the ejection speed is head No. 0002 based on the measurement conditions, and then transitions to step S53. Next, in step S53, the Vj adjustment control circuit 4 performs a camera observation position adjustment process. In the camera observation position adjustment process, the droplet observation device (camera) 6 mechanically moves to a position where it can observe the droplets of the second droplet ejection device 14. After that, after deleting the medium, a second drip tray for receiving the droplets is prepared. Here, since the drip tray is in the same position as the normal medium, it may be a method of mechanically moving the inkjet head to a position shifted from the medium and setting it at the position where the drip tray is located.

[0028] Next, the second LED 47 is turned on, an image is acquired by the droplet observation device 6, the nozzle surface of the second droplet ejection device 14 is discriminated, and after the discrimination of the nozzle surface, a distance corresponding to the media gap in the head specification (for example, 1 mm) from the nozzle surface is prepared as a determination line by image processing. As for the measurement of the ejection speed, it is possible to calculate the ejection speed based on how much time it takes to reach a distance of 1 mm from the nozzle surface. Note that the second LED 47 is turned on or off in synchronization with the driving frequency, which facilitates observation by the camera.

[0029] Also, regarding the delay time of the second LED 47, using the example of the driving waveform in FIG. 11 described later, when the delay time is 0 us, the driving waveform remains at the intermediate potential at the timing of 0 us in FIG. 11. In the image captured by the camera at this delay time, droplets cannot yet be confirmed on the nozzle surface. For example, the head may have a stacked piezo type configuration. At around 8 to 9 us in FIG. 11, it becomes the timing when droplets can be seen on the nozzle surface. Let this time (this delay time) be t1. On the other hand, if the delay time when the droplet reaches the 1 mm line is t2, the ejection speed v1 is calculated by the following formula (1). V1 = 1mm / (t2 - t1) ··· (1)

[0030] Also, although the appropriate ejection speed varies depending on the inkjet head (e.g., stacked piezo structure) and the specifications of the liquid chamber structure, it is said that as long as the variation is within the range of ±15 to 20%, the image quality is not inferior. In the present embodiment, if the ejection speed is within ±20% from the reference speed, it is determined as OK (appropriate) and processed.

[0031] Next, in step S54, the Vj adjustment control circuit 4 performs ejection processing from the nozzles of all channels. In the present embodiment, since the drive frequency can be selected according to the specifications, for example, it is set to 2 kHz. The ejection processing is for pre-checking whether droplets can be ejected from the nozzles of all channels. In step S55, the Vj adjustment control circuit 4 checks whether droplets are being ejected from the nozzles of all channels. If droplets are not being ejected from the nozzles of all channels (step S55: No), the Vj adjustment control circuit 4 transitions to step S56 and checks whether the number of wipings is 3 or more.

[0032] If the number of wipings is less than 3 (step S56: No), the Vj adjustment control circuit 4 transitions to step S57, refills the ink, performs wiping, and adjusts the meniscus of the nozzles of each channel. Then, it returns to step S55. If droplets are being ejected from the nozzles of all channels (step S55: Yes), and if the number of wipings is 3 or more (step S56: Yes), it transitions to step S58, and the Vj adjustment control circuit 4 ejects droplets from only the nozzles of the channels where droplet ejection is possible, starting from the 1-channel side. At this time, the drive frequency is adjustable in 1 kHz increments from a low frequency (e.g., 2 kHz). For example, first, the Vj adjustment control circuit 4 ejects droplets from the nozzles of the 1-channel at a drive frequency of 2 kHz. Next, in step S59, the Vj adjustment control circuit 4 measures the ejection speed of the droplets. Details of the measurement process of the ejection speed of the droplets will be described later.

[0033] Next, in step S60, the Vj adjustment control circuit 4 determines whether the measured ejection speed is within the specified speed. When the measured ejection speed is within the specified speed (step S60: Yes), the Vj adjustment control circuit 4 stores the voltage value in the memory 5 in step S64. On the other hand, when the measured ejection speed is not within the specified speed (step S60: No), the Vj adjustment control circuit 4 transitions to step S61 and determines whether the measured ejection speed is faster than the specified speed. When the measured ejection speed is faster than the specified speed (step S61: Yes), the Vj adjustment control circuit 4 transitions to step S63 and lowers the drive voltage. The step voltage for lowering the drive voltage depends on the head specifications, but for example, it may be about 0.1 to 0.2 V. When the measured ejection speed is below the specified speed (step S61: No), the Vj adjustment control circuit 4 transitions to step S62 and raises the drive voltage.

[0034] After the processing in step S62 and step S63 is performed, the process returns to step S60. After the processing in step S64 is performed, the Vj adjustment control circuit 4 transitions to step S65 and determines whether the measurement of the ejection speed has been completed for all the nozzles of all the channels that can be ejected. When the measurement of the ejection speed has not been completed for all the nozzles of all the channels that can be ejected (step S65: No), the process returns to step S58. When the measurement of the ejection speed has been completed for all the nozzles of all the channels that can be ejected (step S65: Yes), the measurement of the ejection speed is terminated.

[0035] Next, with reference to FIGS. 9 to 12, a detailed example of the method for measuring the ejection speed in step S59 of FIG. 7 will be described. FIGS. 9 to 12 are diagrams for explaining an example of the ejection speed measurement process in the liquid ejection apparatus according to the present embodiment.

[0036] In this embodiment, the Vj adjustment control circuit 4 measures the ejection speed using the droplet observation device 6. There are two patterns of the droplet state of the droplets ejected from the nozzle, as shown in FIGS. 9 and 10. One pattern is the case where one droplet exists in the acquired image. The other pattern is the case where two or more droplets exist in the acquired image. Further, when automatically measuring the ejection speed of the droplets, the Vj adjustment control circuit 4 binarizes the acquired image. By binarizing the image, the area of the droplets can be set to 1 and the other areas can be set to 0 within the image area, so that the distance between the droplets can be calculated.

[0037] First, as shown in FIG. 11, a method for measuring the ejection speed when there is one droplet in the acquired image will be described. The droplet observation device 6 acquires an image at a delay time a (μs). Next, the droplet observation device 6 acquires an image at a delay time a + b (μs). Then, the droplet observation device 6 superimposes and draws the later acquired image on the previously acquired image (the former image) by an OR process. From this, the droplet observation device 6 can calculate the distance n (mm) between the two droplets based on the pixel value = m of the two droplets in the image, so the ejection speed v1 = n (mm) / b (μs) can be obtained.

[0038] Next, as shown in FIG. 12, a method for measuring the ejection speed when there are two or more droplets in the acquired image will be described. For example, the droplet observation device 6 calculates the ejection speed for the two lower droplets existing in the acquired image. As shown in FIG. 12, the period w between droplet B and droplet C is w = 1 / driving frequency. Also, the distance between droplet B and droplet C is q (mm) based on the pixel value = p of the two points. Thereby, the droplet observation device 6 can obtain the ejection speed as v2 = q (mm) / w (μs).

[0039] FIG. 13 is a diagram showing an example of the ejection speed when driving the inkjet heads (No. 0001, 0002) with a constant drive waveform in the inkjet head control device according to the present embodiment. FIG. 14 is a diagram showing an example of a voltage value map of the drive waveform for correcting the inkjet head in the inkjet head control device according to the present embodiment. FIG. 15 is a diagram showing an example of the drive waveform of the inkjet head (No. 0001) in the inkjet head control device according to the present embodiment. FIG. 16 is a diagram showing an example of the drive waveform of the inkjet head (No. 0002) in the inkjet head control device according to the present embodiment. FIG. 17 is a diagram showing an example of the ejection speed after correction in the inkjet head control device according to the present embodiment.

[0040] When the voltage value of the drive waveform is not corrected, as shown in FIG. 13, the end portion of the inkjet head has the frequency characteristics shown in FIGS. 1 and 2. Also, in the central portion of the inkjet head, the ejection speed is lower than that of the end portion due to the influence of voltage drop in the power supply line of the piezo. The voltage value map shown in FIG. 14 is a voltage value map adjusted so that the ejection speed of the inkjet head shown in FIG. 13 falls within the ejection speed range specified by the inkjet head in the configuration of the inkjet head control device 2 shown in FIG. 4. In the present embodiment, the voltage value map shows the voltage values for each drive frequency and each channel at a certain ink type and head temperature. Regarding the channels of the nozzles, the nozzles of the driven channels are divided into three, and the voltage (p-p) of the drive waveform is described every 1 kHz of the drive frequency. Further, supplementing the voltage value map shown in FIG. 14, an example of a voltage value map showing three types of voltage values for the end portion (1 to n1ch), the end portion (n2 + 1 to nch), and the central portion (n1 + 1 to n2ch) at each drive frequency (every 1 kHz and the highest drive frequency in the head specification) for each head No., ink type, and head temperature is shown.

[0041] Depending on the characteristics of the inkjet head, the nozzles of the ch in the central part have a slower ejection speed and a higher voltage value, while the nozzles of the ch at the ends tend to have a faster ejection speed and a lower voltage value than the nozzles of the ch in the central part. Therefore, assuming the same voltage values for the ejection speed reduction of the nozzles of the ch in the central part and the voltage values at the ends (for example, 1 to n1ch), ends (for example, n2 + 1 to nch), two types of voltage values, for the ends and the central part, can be used.

[0042] If the drive waveform generation circuit and the analog switch ASW shown in FIGS. 4 and 5 are increased, for example, to three for each ch, three types of voltage values shown in FIG. 14 can be selected and set in a few minutes. In the present embodiment, for the sake of explanation, the minimum configuration including two types of drive waveform generation circuits and analog switches ASW for each ch is described as an example.

[0043] The waveform selection control circuit 33 shown in FIG. 5 sets the voltage values at the ends of the head in FIG. 14 (the voltage values of 1 to n1ch and the voltage values of n2 + 1 to nch) to the same voltage value for switching between two types of drive waveforms, and uses two types of drive voltages, the voltage value at the central part (n1 + 1 to n2ch) and the voltage value at the ends. FIGS. 15 and 16 are examples of drive waveforms, which are created from the data in the drive waveform data table example in FIG. 14. In this example, the drive waveform is generated such that the Vp-p of the drive voltage increases in the order of the slower ejection speed shown in FIG. 13. By driving using a plurality of voltages after correcting the drive voltages at each head No and each drive frequency, the change in the ejection speed can be reduced as in the example of the corrected ejection speed shown in FIG. 17, and the print quality can be improved.

[0044] Here, an example of a method for setting the drive voltage in the normal drive mode will be described with reference to FIGS. 4, 5, and 14.

[0045] First, in step S1, the upper control device 1 transmits a printing operation menu to the inkjet head control device 2. Here, the printing operation menu indicates an operation of printing k lines at a driving frequency of 2 kHz and m lines at a driving frequency of 40 kHz in the first and second liquid ejection devices 13 and 14. The printing operation menu is read by the Vj adjustment control circuit 4.

[0046] Next, in step S2, when driving the first droplet ejection device 13 at a driving frequency of 2 kHz, V4 (= V6) is set for the first drive waveform generation circuit 7 for the end part of the first droplet ejection device 13, and V5 is set for the second drive waveform generation circuit 8 for the central part of the first droplet ejection device 13. Here, V4 (= V6) is the voltage value of the nozzles of 1 to n1ch and the nozzles of n2 + 1 to nch (end part) of the first droplet ejection device 13. Also, V5 is the voltage value of the nozzles of n1 + 1 to n2ch (central part) of the inkjet head.

[0047] Also, in step S2, when driving the second droplet ejection device 14 at a driving frequency of 2 kHz, Vk + 3 (= Vk + 6) is set for the third drive waveform generation circuit 10 for the end part of the second droplet ejection device 14, and Vk + 4 is set for the fourth drive waveform generation circuit 11 for the central part of the second droplet ejection device 14. Here, Vk + 3 (= Vk + 5) is the voltage value of the nozzles of 1 to n1ch and the nozzles of n2 + 1 to nch (end part) of the second droplet ejection device 14. Also, Vk + 4 is the voltage value of the nozzles of n1 + 1 to n2ch (central part) of the second droplet ejection device 14.

[0048] In step S3, when printing the k line by the droplet discharge device 30 at a drive frequency of 2 kHz, referring to FIG. 5, at the ends of the droplet discharge device 30 (the nozzles of 1 to n1ch and n2 + 1 to nch), the analog switch ASW connected to the first drive waveform generation circuit 31 by the waveform selection control circuit 33 is turned on, and the drive waveform generated by the first drive waveform generation circuit 31 is applied to the piezoelectric element. At the nozzles in the central part (n + 1 to n2ch) of the droplet discharge device 30, the analog switch ASW connected to the drive waveform generation circuit 32 by the waveform selection control circuit 33 is turned on, and the drive waveform generated by the second drive waveform generation circuit 32 is applied to the piezoelectric element.

[0049] In step S4, when driving the nozzles of the first droplet discharge device 13 at a drive frequency of 40 kHz, set V118 (= V120) in the first drive waveform generation circuit 7 (for the ends) and set V119 in the second drive waveform generation circuit 8 (for the central part). Also, when driving the nozzles of the second droplet discharge device 14 at a drive frequency of 40 kHz, set Vk + 117 (Vk + 119) in the third drive waveform generation circuit 10 (for the ends) and set Vk + 118 in the fourth drive waveform generation circuit 11 (for the central part). Here, V118 is the voltage value of the nozzles of 1 to n1ch and n2 + 1 to nch, which are the ends of the first droplet discharge device 13, and V119 is the voltage value of n1 + 1 to n2ch, which is the central part of the first droplet discharge device 13. Also, here, Vk + 117 is the voltage value of the nozzles of 1 to n1ch and n2 + 1 to nch, which are the ends of the second droplet discharge device 14, and Vk + 118 is the voltage value of n1 + 1 to n2ch, which is the central part of the second droplet discharge device 14.

[0050] In step S5, when printing the m line by the first and second droplet discharge devices 13 and 14 at a drive frequency of 40 kHz, in the same manner as in step S3, apply a drive waveform to the piezoelectric element.

[0051] FIG. 18 and FIG. 19 are diagrams schematically showing an example of the overall configuration of an inkjet printer, which is an example of the liquid ejection device according to the present embodiment. Specifically, FIG. 18 is a perspective view of the inkjet printer 100, and FIG. 19 is a perspective side view of the inkjet printer 100.

[0052] As shown in FIGS. 18 and 19, the inkjet printer 100 (an example of a liquid ejection device or an image forming device) according to the present embodiment includes a carriage 101 movable in the main scanning direction inside the apparatus main body, a recording head 102 (droplet ejection devices 13 and 14 such as an inkjet head) mounted on the carriage 101, an ink cartridge 103 that supplies ink to the recording head 102, and other components such as a printing mechanism unit. A paper feed cassette (or a paper feed tray may also be used) 104 capable of loading a large number of recording media such as sheets of paper P from the front side can be detachably attached to the lower part of the apparatus main body of the inkjet printer 100. In addition, in the inkjet printer 100, a manual feed tray 105 for manually feeding the paper P can be opened and laid down.

[0053] The inkjet printer 100 takes in the paper P fed from the paper feed cassette 104 or the manual feed tray 105, records a required image by the above-described printing mechanism unit, and then ejects the paper to a paper discharge tray 106 mounted on the rear side. Hereinafter, although the case where the recording medium is the paper P will be described as an example, as the recording medium, in addition to paper, a sheet-like material such as a film or plastic can be adopted as long as it is an object of image forming output.

[0054] In addition, the printing mechanism unit holds the carriage 101 slidably in the main scanning direction (perpendicular to the paper surface) with the main guide rod 107 and the sub-guide rod 108, which are guide members horizontally mounted on the left and right side plates. The carriage 101 is equipped with a liquid ejection unit 440 integrating the recording head 102 and the head tank 441. The recording head 102 mounted on the liquid ejection unit 440 ejects ink droplets of each color: Yellow, Cyan, Magenta, and Black. A plurality of ink ejection ports for ejecting these inks of each color are arranged in a direction (sub-scanning direction) intersecting the main scanning direction, and the ink ejection ports are directed downward.

[0055] Each ink cartridge 103 for supplying inks of each color to the recording head 102 is detachably mounted on the carriage 101. The ink cartridge 103 has an air port communicating with the atmosphere for standby upward, a supply port for supplying ink to the recording head 102 downward, and a porous body filled with ink inside. Due to the capillary force of this porous body, the ink supplied to the recording head 102 is maintained at a slight negative pressure. In this embodiment, the case where the recording head 102 is provided for each color is taken as an example, but one head having nozzles for ejecting inks of each color may also be used.

[0056] The rear side (downstream side in the paper conveyance direction) of the carriage 101 is slidably mounted on the main guide rod 107, and the front side (upstream side in the paper conveyance direction) is slidably mounted on the sub-guide rod 108. Then, in order to move and scan the carriage 101 in the main scanning direction, a timing belt 112 is stretched between a driving pulley 110 and a driven pulley 111 that are rotationally driven by the main scanning motor 109. The timing belt 112 and the carriage 101 are fixed, and the carriage 101 is reciprocally driven by the forward and reverse rotations of the main scanning motor 109.

[0057] On one hand, in order to convey the paper set in the paper feed cassette 104 to the lower side of the recording head 102, a paper feed roller 113, a friction pad 114, a guide member 115, a conveyance roller 116, a conveyance roller 117, and a tip roller 118 are provided. The paper feed roller 113 and the friction pad 114 separate and feed the paper P from the paper feed cassette 104, and the guide member 115 guides the separated and fed paper P.

[0058] The conveyance roller 116 conveys the fed paper P after inverting it. The conveyance roller 117 is pressed against the circumferential surface of the conveyance roller 116, and the tip roller 118 defines the feeding angle of the paper P from the conveyance roller. Also, the conveyance roller 116 is rotationally driven by a sub-scanning motor via a gear train.

[0059] A printing receiving member 119, which is a paper guide member that guides the paper P fed out from the conveyance roller 116 below the recording head 102 corresponding to the movement range of the carriage 101 in the main scanning direction, is provided. On the downstream side in the paper conveyance direction of this printing receiving member 119, a conveyance roller 120 and a booster 121 that are rotationally driven are provided to feed the paper P in the paper discharge direction. Further, a paper discharge roller 122 and a booster 123 that feed the paper P to the paper discharge tray 106, and guide members 124 and 125 that form a paper discharge path are arranged.

[0060] When recording an image on the paper P, the controller of the inkjet printer 100 drives the recording head 102 in accordance with an image signal while moving the carriage 101, thereby discharging ink onto the stopped paper P to record one scan. Then, the controller of the inkjet printer 100 conveys the paper P by a predetermined amount and then performs recording for the next line. Also, when the controller of the inkjet printer 100 receives a recording end signal or a signal indicating that the rear end of the paper P has reached the recording area, it ends the recording operation and discharges the paper P.

[0061] The recording head 102 includes a piezoelectric element as a driving element for driving each of the plurality of nozzles as described above. That is, in the inkjet printer 100 according to the present embodiment, a piezoelectric element is used as an actuator element that generates a discharge force for discharging ink (an example of droplets) from each of the plurality of nozzles. By applying a predetermined driving waveform to this piezoelectric element, ink is discharged from each nozzle. That is, the recording head 102 (an example of a liquid discharge head) has a plurality of nozzles and a piezoelectric element (piezo) provided for each of the nozzles to which a driving signal (driving waveform) is applied to discharge ink from the nozzle.

[0062] Further, a maintenance and recovery device 126 for recovering discharge defects of the recording head 102 is disposed at a position outside the recording area on the right end side in the moving direction of the carriage 101. The maintenance and recovery device 126 has a capping means, a suction means, and a cleaning means. During the printing standby, the carriage 101 is moved to the side of the maintenance and recovery device 126, and the recording head 102 is capped by the capping means. Thereby, the discharge port portion is kept in a wet state, and discharge defects due to ink drying are prevented.

[0063] Further, the recording head 102 discharges (performs empty discharge) ink that has nothing to do with recording to the maintenance and recovery device 126 during recording or the like, thereby making the ink viscosity of all discharge ports constant and maintaining stable discharge performance. Specifically, when a discharge defect occurs or the like, the capping means seals the discharge port (nozzle) of the recording head 102, and the suction means sucks out bubbles and the like together with the ink from the discharge port through the tube. Then, ink, dust, etc. adhering to the discharge port surface are removed by the cleaning means, and the discharge defect is recovered. Also, the sucked ink is discharged to a waste ink reservoir installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

[0064] Also, the liquid ejection head such as the recording head 102 is not limited to the pressure generating means to be used. For example, in addition to the piezoelectric actuator (which may use a laminated piezoelectric element) as described in the above embodiment, a thermal actuator using an electrothermal conversion element such as a heating resistor, an electrostatic actuator including a diaphragm and a counter electrode, etc. may be used.

[0065] Also, in the terms of the present application, image formation, recording, printing, copying, printing, shaping, etc. are all regarded as synonyms.

[0066] In the present embodiment, the liquid ejection unit is an integrated unit of a liquid ejection head, functional components, and mechanisms, and is an aggregate of components related to liquid ejection. For example, the liquid ejection unit 440 includes at least one of a head tank such as the ink cartridge 103, the carriage 101, a supply mechanism, a maintenance and recovery device 126, and a configuration of a main scanning movement mechanism combined with the recording head 102.

[0067] Here, the integration includes, for example, those in which the liquid ejection head, functional components, and mechanisms are fixed to each other by fastening, adhesion, engagement, etc., and those in which one is movably held with respect to the other. Also, the liquid ejection head and the functional components and mechanisms may be configured to be detachable from each other.

[0068] For example, as the liquid ejection unit, there is one in which the liquid ejection head and the head tank are integrated. Also, there is one in which the liquid ejection head and the head tank are integrated by being connected to each other with a tube or the like. Here, a unit including a filter can also be added between the head tank and the liquid ejection head of these liquid ejection units.

[0069] Also, as the liquid ejection unit, there is one in which the liquid ejection head and the carriage 101 are integrated.

[0070] In addition, as a liquid ejection unit, there is one in which a liquid ejection head is movably held by a guide member that forms part of a main scanning movement mechanism, and the liquid ejection head and the main scanning movement mechanism are integrated. Also, there is one in which the liquid ejection head, the carriage 101, and the main scanning movement mechanism are integrated.

[0071] In addition, as a liquid ejection unit, there is one in which a cap member that is part of the maintenance and recovery device 126 is fixed to the carriage 101 to which the liquid ejection head is attached, and the liquid ejection head, the carriage 101, and the maintenance and recovery device 126 are integrated.

[0072] In addition, as a liquid ejection unit, there is one in which a tube is connected to a liquid ejection head to which a head tank or a flow path component is attached, and the liquid ejection head and the supply mechanism are integrated. Through this tube, the liquid from the liquid storage source is supplied to the liquid ejection head.

[0073] The main scanning movement mechanism shall include the guide member alone. Also, the supply mechanism shall include the tube alone and the loading unit alone.

[0074] In addition, in the present application, a liquid ejection device such as the inkjet printer 100 is a device that includes a liquid ejection head or a liquid ejection unit and drives the liquid ejection head to eject liquid. The liquid ejection device includes not only a device capable of ejecting liquid onto an object to which liquid can adhere, but also a device capable of ejecting liquid into the air or into a liquid.

[0075] This liquid ejection device can also include means related to the feeding, conveyance, and paper discharge of an object to which liquid can adhere, as well as other pre-treatment devices, post-treatment devices, and the like.

[0076] For example, as a liquid ejection device, there is an image forming device that ejects ink to form an image on paper, and a three-dimensional modeling device (3D modeling device) that ejects a modeling liquid onto a powder layer formed in layers of powder in order to model a three-dimensional object (3D object).

[0077] Moreover, the liquid ejection device is not limited to one in which a significant image such as characters or figures is visualized by the ejected liquid. For example, those that form a pattern or the like having no meaning by itself, and those that create a three-dimensional image are also included.

[0078] The above-mentioned objects to which the liquid can adhere mean those to which the liquid can adhere at least temporarily, such as those that adhere and stick, those that adhere and penetrate, etc. Specific examples include recording media such as paper, recording paper, recording sheets, films, cloth, electronic substrates, electronic components such as piezoelectric elements, powder layers (powder layers), organ models, media such as test cells, etc., and all objects to which the liquid adheres are included unless otherwise particularly limited.

[0079] The material of the above-mentioned objects to which the liquid can adhere may be paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc., as long as the liquid can adhere even temporarily.

[0080] Also, the liquid may have a viscosity or surface tension that can be ejected from the liquid ejection head, and is not particularly limited, but preferably has a viscosity of 30 mPa·s or less at normal temperature and pressure, or by heating or cooling. More specifically, it includes solutions, suspensions, emulsions, etc. containing solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, functional imparting materials such as surfactants, biocompatible materials such as DNA, amino acids, proteins, calcium, edible materials such as natural pigments, etc. These can be used, for example, in applications such as inkjet inks, surface treatment liquids, components for electronic elements and light-emitting elements, liquids for forming electronic circuit resist patterns, and material liquids for three-dimensional modeling.

[0081] Moreover, there is a liquid ejection device in which the liquid ejection head and the object to which the liquid can adhere move relatively, but it is not limited to this. Specific examples include serial type devices that move the liquid ejection head, line type devices that do not move the liquid ejection head, etc.

[0082] In addition, as liquid ejection devices, there are also treatment liquid coating devices that eject a treatment liquid onto paper in order to coat the surface of the paper for purposes such as modifying the surface of the paper, and injection granulation devices that granulate fine particles of raw materials by injecting a composition liquid in which the raw materials are dispersed in a solution through nozzles, etc.

[0083] Thus, according to the liquid ejection device according to this embodiment, it is possible to reduce the difference in ejection speed between the central part and the end part of the nozzle row, including changes in the drive frequency of the nozzles included in the liquid ejection head, variations between the liquid ejection heads, the environmental temperature in the printing device, and variations in the type of ink used. Therefore, the printing quality can be improved.

[0084] Note that the program executed by the liquid ejection device of this embodiment is provided by being pre - incorporated in a ROM (Read Only Memory) or the like. The program executed by the liquid ejection device of this embodiment may be configured to be recorded on a computer - readable recording medium such as a CD - ROM, a flexible disk (FD), a CD - R, a DVD (Digital Versatile Disk), etc. in an installable format or an executable format file and provided.

[0085] Furthermore, the program executed by the liquid ejection device of this embodiment may be configured to be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Also, the program executed by the liquid ejection device of this embodiment may be configured to be provided or distributed via a network such as the Internet.

[0086] The program executed by the liquid ejection device according to the present embodiment has a module configuration including the above-described respective parts (drive signal output part, voltage information acquisition part, control part). As actual hardware, for example, a processor such as a CPU (Central Processing Unit) reads the program from the above-described ROM and executes it, whereby the above-described respective parts are loaded onto the main storage device, and the drive signal output part, voltage information acquisition part, and control part are generated on the main storage device.

[0087] Aspects of the present invention are as follows, for example. <1> A liquid ejection head driving device that drives a liquid ejection head having a plurality of nozzles that eject liquid in response to an input drive signal, a drive signal output part that generates the drive signal based on voltage information related to the voltage applied to the piezoelectric element of the nozzle and outputs the drive signal to the liquid ejection head; a voltage information acquisition part that acquires appropriate voltage information for which the ejection speed falls within a predetermined range based on the droplet speed information acquired from droplet speed measurement means that measures the ejection speed of droplets ejected from the liquid ejection head and the voltage information; a storage part that stores the appropriate voltage information in association with the identification information of the nozzle and the drive frequency of the nozzle; a control part that acquires the appropriate voltage information corresponding to the identification information and the drive frequency from the storage part and causes the drive signal output part to output the drive signal based on the appropriate voltage information; A liquid ejection head driving device comprising: <2> Further comprising the droplet speed measurement means, wherein the droplet speed measurement means has a camera that measures the droplets, and the camera is movable with respect to the liquid ejection head and can measure the ejection speed for each nozzle. The liquid ejection head driving device according to <1>. <3> The liquid ejection head driving device has a normal driving mode and a correction mode, When transitioning to the correction mode, the voltage information acquisition unit acquires the appropriate voltage information based on the droplet discharge rate information and the voltage information, for the liquid discharge head driving device according to <1> or <2>. <4> The voltage information acquisition unit acquires the appropriate voltage information for each liquid discharge head, for the liquid discharge head driving device according to any one of <1> to <3>. <5> The voltage information acquisition unit acquires the appropriate voltage information for each temperature around the liquid discharge head, for the liquid discharge head driving device according to any one of <1> to <4>. <6> The voltage information acquisition unit acquires the appropriate voltage information for each type of ink discharged from the liquid discharge head, for the liquid discharge head driving device according to any one of <1> to <5>. <7> A liquid discharge head driving system including a liquid discharge head driving device that drives a liquid discharge head having a plurality of nozzles that discharge liquid according to an input drive signal, and a droplet discharge rate measuring means that is movable relative to the liquid discharge head and includes a camera capable of measuring the discharge rate of liquid for each nozzle of the liquid discharge head. The liquid discharge head driving device includes a drive signal output unit that generates the drive signal based on voltage information related to the voltage applied to the piezoelectric element of the nozzle and outputs the drive signal to the liquid discharge head. a voltage information acquisition unit that acquires appropriate voltage information based on the droplet discharge rate information obtained from the droplet discharge rate measuring means that measures the discharge rate of the droplets discharged from the liquid discharge head and the voltage information, such that the discharge rate is within a predetermined range. a storage unit that stores the appropriate voltage information in association with the identification information of the nozzle and the drive frequency of the nozzle. a control unit that acquires the appropriate voltage information corresponding to the identification information and the drive frequency from the storage unit and causes the drive signal output unit to output the drive signal based on the appropriate voltage information. The droplet discharge rate measuring means is communicable with the liquid discharge head driving device, for the liquid discharge head driving system. <8> A liquid ejection head having a plurality of nozzles that eject liquid in response to an input drive signal, A drive signal output unit that generates the drive signal based on voltage information related to the voltage applied to the piezoelectric element of the nozzle and outputs the drive signal to the liquid ejection head; A voltage information acquisition unit that acquires appropriate voltage information based on the droplet velocity information acquired from a droplet velocity measurement means that measures the ejection velocity of droplets ejected from the liquid ejection head and the voltage information, such that the ejection velocity falls within a predetermined range; A storage unit that stores the appropriate voltage information in association with the identification information of the nozzle and the drive frequency of the nozzle; A control unit that acquires the appropriate voltage information corresponding to the identification information and the drive frequency from the storage unit, and causes the drive signal output unit to output the drive signal based on the appropriate voltage information; A liquid ejection device comprising: <9> A liquid ejection head driving method executed by a liquid ejection head driving device that drives a liquid ejection head having a plurality of nozzles that eject liquid in response to an input drive signal, the method comprising: Generating the drive signal based on voltage information related to the voltage applied to the piezoelectric element of the nozzle and outputting the drive signal to the liquid ejection head; Acquiring appropriate voltage information based on the droplet velocity information acquired from a droplet velocity measurement means that measures the ejection velocity of droplets ejected from the liquid ejection head and the voltage information, such that the ejection velocity falls within a predetermined range; Acquiring the appropriate voltage information corresponding to the identification information and the drive frequency from a storage unit that stores the appropriate voltage information in association with the identification information of the nozzle and the drive frequency of the nozzle, and causing the drive signal to be output based on the appropriate voltage information; A liquid ejection head driving method including: <10> A computer, A drive signal output unit that generates the drive signal based on voltage information related to the voltage applied to the piezoelectric element of the nozzle of a liquid ejection head that ejects liquid in response to an input drive signal and outputs the drive signal to the liquid ejection head; Based on the droplet velocity information obtained from the droplet velocity measuring means for measuring the ejection velocity of droplets ejected from the liquid ejection head and the voltage information, a voltage information acquisition unit that acquires appropriate voltage information for which the ejection velocity falls within a predetermined range; From a storage unit that stores the appropriate voltage information in association with the identification information of the nozzle and the driving frequency of the nozzle, the appropriate voltage information corresponding to the identification information and the driving frequency is acquired, and based on the appropriate voltage information, a control unit that causes the driving signal output unit to output the driving signal; A program for causing it to function.

Explanation of Signs

[0088] 1 Higher-level control device 2 Inkjet head control device 3 Operation mode switching circuit 4 Vj adjustment control circuit 5 Memory 6 Droplet observation device 7, 8, 10, 11, 31, 32 Driving waveform generation circuit 9, 12, 33 Waveform selection control circuit 13, 14, 30 Droplet ejection device

Prior Art Documents

Patent Documents

[0089]

Patent Document 1

Claims

1. A liquid ejection head driving device for driving a liquid ejection head having a plurality of nozzles that eject liquid in response to an input drive signal, a drive signal output unit that generates the drive signal based on voltage information related to the voltage applied to the piezoelectric element of the nozzle and outputs the drive signal to the liquid ejection head; a voltage information acquisition unit that acquires appropriate voltage information based on the droplet velocity information acquired from droplet velocity measuring means for measuring the ejection velocity of droplets ejected from the liquid ejection head and the voltage information, such that the ejection velocity falls within a predetermined range; a storage unit that stores the appropriate voltage information in association with the identification information of the nozzle and the drive frequency of the nozzle; a control unit that acquires the appropriate voltage information corresponding to the identification information and the drive frequency from the storage unit and causes the drive signal output unit to output the drive signal based on the appropriate voltage information; A liquid ejection head driving device comprising the above.

2. further comprising the droplet velocity measuring means, wherein the droplet velocity measuring means has a camera for measuring the droplets, and the camera is movable with respect to the liquid ejection head and is capable of measuring the ejection velocity for each nozzle. The liquid ejection head driving device according to Claim 1.

3. The liquid ejection head driving device has a normal driving mode and a correction mode, and the voltage information acquisition unit acquires the appropriate voltage information based on the droplet velocity information and the voltage information when transitioning to the correction mode. The liquid ejection head driving device according to Claim 1 or 2.

4. The voltage information acquisition unit acquires the appropriate voltage information for each liquid ejection head. The liquid ejection head driving device according to Claim 1.

5. The voltage information acquisition unit acquires the appropriate voltage information for each temperature around the liquid ejection head. The liquid ejection head driving device according to Claim 1.

6. The voltage information acquisition unit acquires the appropriate voltage information for each type of ink ejected from the liquid ejection head. The liquid ejection head driving device according to Claim 1.

7. A liquid ejection head driving system comprising a liquid ejection head driving device for driving a liquid ejection head having a plurality of nozzles that eject liquid in response to an input drive signal, and droplet velocity measuring means comprising a camera that is movable with respect to the liquid ejection head and is capable of measuring the ejection velocity of liquid for each nozzle of the liquid ejection head, wherein the liquid ejection head driving device is generating the drive signal based on voltage information related to the voltage applied to the piezoelectric element of the nozzle, and outputting the drive signal to the liquid ejection head; acquiring appropriate voltage information at which the ejection speed is within a predetermined range, based on the droplet speed information acquired from droplet speed measuring means for measuring the ejection speed of droplets ejected from the liquid ejection head and the voltage information; a storage unit that stores the appropriate voltage information in association with the identification information of the nozzle and the drive frequency of the nozzle; a control unit that acquires the appropriate voltage information corresponding to the identification information and the drive frequency from the storage unit, and causes the drive signal output unit to output the drive signal based on the appropriate voltage information; The liquid ejection head drive system, wherein the droplet speed measuring means is communicable with the liquid ejection head drive device.

8. a liquid ejection head having a plurality of nozzles that eject liquid in response to an input drive signal; generating the drive signal based on voltage information related to the voltage applied to the piezoelectric element of the nozzle, and outputting the drive signal to the liquid ejection head; acquiring appropriate voltage information at which the ejection speed is within a predetermined range, based on the droplet speed information acquired from droplet speed measuring means for measuring the ejection speed of droplets ejected from the liquid ejection head and the voltage information; a storage unit that stores the appropriate voltage information in association with the identification information of the nozzle and the drive frequency of the nozzle; a control unit that acquires the appropriate voltage information corresponding to the identification information and the drive frequency from the storage unit, and causes the drive signal output unit to output the drive signal based on the appropriate voltage information; A liquid ejection device comprising:

9. A liquid ejection head drive method executed by a liquid ejection head drive device that drives a liquid ejection head having a plurality of nozzles that eject liquid in response to an input drive signal, the method comprising: generating the drive signal based on voltage information related to the voltage applied to the piezoelectric element of the nozzle, and outputting the drive signal to the liquid ejection head; acquiring appropriate voltage information at which the ejection speed is within a predetermined range, based on the droplet speed information acquired from droplet speed measuring means for measuring the ejection speed of droplets ejected from the liquid ejection head and the voltage information; Obtaining the appropriate voltage information corresponding to the identification information and the drive frequency from a storage unit that stores the appropriate voltage information in association with the identification information of the nozzle and the drive frequency of the nozzle, and outputting the drive signal based on the appropriate voltage information; A method for driving a liquid ejection head including the above.

10. A computer, A drive signal output unit that generates the drive signal based on voltage information related to the voltage applied to the piezoelectric element of the nozzle included in the liquid ejection head that ejects liquid in response to the input drive signal, and outputs the drive signal to the liquid ejection head; A voltage information acquisition unit that acquires appropriate voltage information at which the ejection speed falls within a predetermined range based on the droplet speed information acquired from a droplet speed measurement unit that measures the ejection speed of droplets ejected from the liquid ejection head and the voltage information; A control unit that acquires the appropriate voltage information corresponding to the identification information and the drive frequency from a storage unit that stores the appropriate voltage information in association with the identification information of the nozzle and the drive frequency of the nozzle, and causes the drive signal output unit to output the drive signal based on the appropriate voltage information; A program for causing the computer to function as described above.

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