Liquid ejecting head driving apparatus, liquid ejecting head driving system, liquid ejecting head driving method, liquid ejecting apparatus, and program product

Abstract

The invention provides a liquid ejecting head driving apparatus, a system, a method, a liquid ejecting apparatus, and a program product capable of improving printing quality. The liquid ejecting head driving apparatus that drives a liquid ejecting head having a plurality of nozzles that eject liquid according to an input driving signal includes: a driving signal output section that generates a driving signal based on voltage information related to a voltage applied to a piezoelectric element of the nozzles, and outputs the driving signal to the liquid ejecting head; a voltage information acquisition unit that acquires appropriate voltage information in which the ejection velocity is within a predetermined range, on the basis of droplet velocity information and voltage information acquired from a droplet velocity measurement unit that measures the ejection velocity of droplets ejected by the liquid ejection head; a storage unit that associates and stores the appropriate voltage information with identification information of the nozzle and a driving frequency of the nozzle; and a control unit that acquires, from the storage unit, appropriate voltage information corresponding to the identification information and the drive frequency, and causes the drive signal output unit to output the drive signal on the basis of the appropriate voltage information.

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 product. Background Art

[0002] A droplet ejection device has a characteristic in which the ejection speed of droplets from a nozzle varies depending on a driving frequency. In order to suppress such a variation in ejection speed, a technique for changing the driving voltage and driving waveform of a head according to the driving frequency has been developed.

[0003] In addition, an inkjet head of a droplet ejection device has a plurality of nozzles assembled in one column, and has characteristics in which the ejection speeds are different between the central portion and the end portion of the column. In the past design, the difference in ejection speed between the central portion and the end portion of the column was not a problem, but as the driving of the head becomes higher in frequency and the driving frequency band of the head becomes wider, it becomes difficult to suppress the difference in ejection speed between the central portion and the end portion of the column to a level where it is not a problem over the entire frequency band. The technique disclosed in Patent Document 1 is to set two types of driving waveforms for the head within a column of nozzles, thereby enabling correction of the difference in ejection speed between the central portion and the end portion of the column.

[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 peak value are input in advance, it is difficult to take into account variations due to unevenness between heads, the ambient temperature in a printing device, and the type of ink liquid used.

[0005] The present invention has been made in view of the above circumstances, 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 product that can improve printing quality.

[0006] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2021-138043 Summary of the Invention

[0007] In order to solve the above problems and achieve the object, the present invention relates to a liquid ejection head driving device for driving a liquid ejection head having a plurality of nozzles for ejecting liquid according to an input drive signal, characterized by comprising: a drive signal output unit that generates the drive signal based on voltage information related to the voltage in a piezoelectric element applied to the nozzle and outputs the drive signal to the liquid ejection head; a voltage information acquisition unit that acquires appropriate voltage information within a specified range of the ejection speed 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 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.

[0008] According to the present invention, there is an effect that the printing quality can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 The figure shows 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.

[0010] Figure 2 The figure shows an example of the characteristics of the drive frequency of the nozzles in all channels of the liquid ejection head included in the liquid ejection device according to the present embodiment.

[0011] Figure 3 The figure shows an example of the characteristics of the ejection speed within one row of the nozzles of the liquid ejection head included in the liquid ejection device according to the present embodiment.

[0012] Figure 4 The figure shows an example of a schematic configuration diagram of an inkjet head control device having a Vj adjustment control circuit according to the present embodiment.

[0013] Figure 5 The figure shows an example of a schematic configuration diagram of an inkjet head having a liquid ejection device according to the present embodiment.

[0014] Figure 6 The figure shows an example of a diagram for explaining the measurement process of the ejection speed of droplets in the inkjet head control device according to the present embodiment.

[0015] Figure 7 The figure shows an example of a flowchart of the measurement process flow of the ejection speed of droplets in the inkjet head control device according to the present embodiment.

[0016] Figure 8 Shown is an example of a flowchart of a measurement process for the ejection speed of droplets in an inkjet head control device according to this embodiment.

[0017] Figure 9 Shown is a diagram for explaining an example of a measurement process for the ejection speed in a liquid ejection device according to this embodiment.

[0018] Figure 10 Shown is a diagram for explaining an example of a measurement process for the ejection speed in a liquid ejection device according to this embodiment.

[0019] Figure 11 Shown is a diagram for explaining an example of a measurement process for the ejection speed in a liquid ejection device according to this embodiment.

[0020] Figure 12 Shown is a diagram for explaining an example of a measurement process for the ejection speed in a liquid ejection device according to this embodiment.

[0021] Figure 13 Shown is a diagram of an example of the ejection speed when driving an inkjet head (No.0001, 0002) with a constant drive waveform in an inkjet head control device according to this embodiment.

[0022] Figure 14 Shown is a diagram of an example of a voltage value mapping for correcting the drive waveform of an inkjet head in an inkjet head control device according to this embodiment.

[0023] Figure 15 Shown is a diagram of an example of the drive waveform of an inkjet head (No.0001) in an inkjet head control device according to this embodiment.

[0024] Figure 16 Shown is a diagram of an example of the drive waveform of an inkjet head (No.0002) in an inkjet head control device according to this embodiment.

[0025] Figure 17 Shown is a diagram of an example of the corrected ejection speed in an inkjet head control device according to this embodiment.

[0026] Figure 18 Shown is a schematic diagram of an example of the overall configuration of an inkjet printer, which is an example of a liquid ejection device according to this embodiment.

[0027] Figure 19 Shown is a schematic diagram of an example of the overall configuration of an inkjet printer, which is an example of a liquid ejection device according to this embodiment. Detailed implementation mode

[0028] Hereinafter, with reference to the accompanying drawings, 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 product will be described in detail.

[0029] Figure 1 The figure shows an example of the characteristics of the driving frequency of the nozzles at the end of the liquid ejection head included in the liquid ejection device according to the present embodiment. In Figure 1 it, the vertical axis represents the rate of change of the ejection speed (ejection speed change rate) of the liquid ejection head (e.g., an inkjet head), and the horizontal axis represents the driving frequency of the nozzles included in the liquid ejection head. Figure 1 The example shown is the characteristics of the driving frequency of the nozzles with a maximum driving frequency of 40 kHz. Below 40 kHz, the ejection speed of the droplets from the nozzles changes due to the driving frequency.

[0030] Figure 2 The figure shows an example of the characteristics of the driving frequency of the nozzles of all channels of the liquid ejection head included in the liquid ejection device according to the present embodiment. In Figure 2 it, the horizontal axis represents the driving frequency, and the vertical axis represents the ejection speed change rate. Figure 2 Each plotting point in it represents the characteristics of the driving frequency of the nozzles located at the central part of the plurality of nozzle rows included in the plurality of liquid ejection heads. More specifically, Figure 2 the example shown is an example of the characteristics of the driving frequency of the nozzles at the central part of each row of five liquid ejection heads having four nozzle rows. In Figure 2 in the liquid ejection head of the example shown, the maximum driving frequency is 40 kHz, but when the driving frequency is 12 kHz or less, in particular, the ejection speed has a tendency to decrease. Further, for each liquid ejection head and each row of liquid ejection heads, the amount of decrease varies. Compared with Figure 1 the characteristics of the driving frequency of the end nozzles of the liquid ejection head shown, Figure 2 in the characteristics of the driving frequency of the nozzles at the central part shown, when the driving frequency is 12 kHz or less, the ejection speed of the droplets changes according to the driving frequency. The difference in this ejection speed can be corrected by changing the driving voltage or driving waveform of the nozzles according to the driving frequency. However, for each liquid ejection head, variations occur in the driving frequency that decreases due to the environmental temperature of the printing device (an example of a liquid ejection device) and the type of ink liquid used. In addition, variations also occur in the decreased ejection speed.

[0031] Figure 3 The figure shows an example of the characteristics of the ejection speed within one row of the nozzles of the liquid ejection head included in the liquid ejection device according to the present embodiment. In Figure 3In the figure, the horizontal axis represents the ch (channel) of the nozzles within a column, and the vertical axis represents the ejection speed of the droplets. Additionally, in Figure 3 the figure, the dashed line represents the characteristics of the ejection speed when the driving frequency is 40 kHz, and the solid line represents the characteristics of the ejection speed during low-frequency driving, and represents the characteristics of the ejection speed when correcting the driving voltage or driving waveform in such a manner that the ejection speed of the nozzles at the end of the liquid ejection head is the same as the characteristics at a driving frequency of 40 kHz.

[0032] In the case of low-frequency driving (for example, Figure 2 in the case of a driving frequency of 12 kHz or less as shown), compared with a driving frequency of 40 kHz, the decrease in the ejection speed of the nozzles in the central portion of the liquid ejection head is large. This decrease amount varies depending on the driving frequency. In all the driving frequency bands used in printing, it is necessary to suppress this decrease amount in the central portion to a level that causes no problem to the printing quality. In the case of this example, by switching the driving waveform so that the ejection speed in the central portion of the liquid ejection head becomes faster, the difference in the ejection speed between the end portion and the central portion 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 of the printing apparatus and the type of ink liquid used. Additionally, variations also occur in the decreased ejection speed.

[0033] Figure 4 Shown is a schematic configuration example of an inkjet head control device having a Vj adjustment control circuit according to the present embodiment. Here, "Vj" of the Vj adjustment control circuit is a term representing "the speed of the droplets ejected from the liquid ejection head". Figure 5 Shown is a schematic configuration example of an inkjet head having a liquid ejection device 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 an example of a liquid ejection head having a plurality of nozzles that eject a liquid (such as ink droplets) according 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.

[0034] The operation mode switching circuit 3 switches the operation mode of the inkjet head control device 2 to the normal driving mode or the appropriate Vj correction mode. The first driving waveform generation circuit 7 and the second driving waveform generation circuit 8 are examples of driving signal output units that generate driving signals (driving waveforms) based on voltage information related to the voltage (voltage value) applied to the piezoelectric elements in the nozzles, and output the driving waveforms to the first droplet ejection device 13. The third driving waveform generation circuit 10 and the fourth driving waveform generation circuit 11 are examples of driving signal output units that generate driving signals (driving waveforms) based on voltage information, and output the driving waveforms to the second droplet ejection device 14.

[0035] The Vj adjustment control circuit 4 is an example of a voltage information acquisition unit. It acquires the voltage value (appropriate voltage information) at which the ejection speeds of the ink ejected from the first and second droplet ejection devices 13 and 14 fall within a specified range, based on the droplet speed information indicating the ejection speed and the voltage information acquired from the droplet observation device 6 (an example of a droplet speed measurement unit) that measures the ejection speeds of the ink ejected from the first and second droplet ejection devices 13 and 14. Here, the Vj adjustment control circuit 4 can acquire the appropriate voltage information for each nozzle of the first and second droplet ejection devices 13 and 14, or can also acquire the appropriate voltage information for each of the blocks (for example, three blocks such as one end, the central part, and the other end of the inkjet head) formed by dividing the multiple nozzles of the first and second droplet ejection devices 13 and 14.

[0036] In addition, when the inkjet head control device 2 switches from the normal driving mode to the appropriate Vj correction mode (an example of a correction mode), the Vj adjustment control circuit 4 can also acquire the appropriate voltage information based on the droplet speed information and the voltage information. Additionally, the Vj adjustment control circuit 4 can acquire the appropriate voltage information for each inkjet head. Further, the Vj adjustment control circuit 4 can also acquire the appropriate voltage information for each temperature around the inkjet head. Moreover, the Vj adjustment control circuit 4 can also obtain the appropriate voltage information for each type of ink ejected from the inkjet head. Here, the type of ink can also be set based on information set by the user, etc.

[0037] The memory 5 is an example of a storage unit that stores by associating appropriate voltage information with the identification information of the nozzles (such as ch numbers) and the driving frequencies of the nozzles. In addition, the Vj adjustment control circuit 4 is an example of a control unit that obtains the appropriate voltage information corresponding to the identification information and driving frequency of the nozzles for adjusting the ejection speed of the ink liquid from the memory 5, and controls the waveform selection control circuits 9 and 12 based on the appropriate voltage information, so that the first to fourth drive waveform generation circuits 7, 8, 10, and 11 output drive waveforms. Thereby, it is possible to reduce the difference in ejection speed between the central part and the end part of the nozzle row including the change in the driving frequency of the nozzles included in the inkjet head, the variation between inkjet heads, the ambient temperature in the liquid ejection device such as the printing device, and the non-uniformity of the types of liquids such as the ink liquid used, and thus it is possible to improve the printing quality. The waveform selection control circuits 9 and 12 are controlled by the Vj adjustment control circuit 4 and select the drive waveforms output to the first and second droplet ejection devices 13 and 14.

[0038] The droplet observation device 6 is an example of a droplet speed measurement unit and has a camera for measuring droplets. Moreover, this camera is arranged to be movable relative to the first and second droplet ejection devices 13 and 14, and measures the ejection speed of the ink liquid for each nozzle. In the present embodiment, the droplet observation device 6 is arranged inside the inkjet head control device 2, but as long as it is in a state where it can communicate with the inkjet head control device 2 through wireless communication or the like, it may also be arranged outside the inkjet head control device 2.

[0039] Two drive waveforms (first drive waveform, second drive waveform) are respectively generated in the first drive waveform generation circuit 7 and the second drive waveform generation circuit 8, and the third drive waveform generation circuit 10 and the fourth drive waveform generation circuit 11. One of the drive waveforms is selected by the analog switch ASW to drive the piezoelectric elements (such as Figure 5 the piezoelectric elements 36 and 39 shown) of the first and second droplet ejection devices 13 and 14 (such as an inkjet head).

[0040] In the following description, when the first drive waveform generation circuit 7 and 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 drive waveform generation circuits. In addition, in Figure 5 , the droplet ejection device 30 represents Figure 4 a detailed configuration example of each of the first droplet ejection device 13 and the second droplet ejection device 14 shown, the drive waveform generation circuit 31 corresponds to Figure 4 the first drive waveform generation circuit 7 or the third drive waveform generation circuit 10 shown, and the drive waveform generation circuit 32 corresponds to Figure 4 the second drive waveform generation circuit 8 or the fourth drive waveform generation circuit 11 shown.

[0041] However, instead of having two drive waveform generation circuits and analog switches ASW for each nozzle 1ch of the inkjet head, if three or more drive waveform generation circuits and analog switches ASW are prepared, multiple types of drive waveforms can be applied to each piezoelectric element instead of two. In this embodiment, the minimum configuration of two drive waveform generation circuits and analog switches ASW will be described.

[0042] 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 (e.g., a camera) 6 enter the appropriate Vj correction mode according to the mode switching instruction from the host control device 1, in order to suppress the reduction amount of the ejection speed at the central part of the inkjet head, the voltage value that satisfies the ejection of the droplet is obtained to suppress the ejection speed that fluctuates for each inkjet head, each channel, and each drive frequency within a specified range. Then, the Vj adjustment control circuit 4 maps the voltage value including the obtained voltage value to the memory 5 for storage.

[0043] In addition, 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 and reads out the voltage value map stored in the appropriate Vj correction mode, provides instructions to the first to fourth drive waveform generation circuits 7, 8, 10, 11 with the appropriate voltage value, and ejects droplets with the appropriate voltage value. Each nozzle has two drive waveform generation circuits in order to be able to generate and output a drive waveform at a drive frequency with no reduction in ejection speed in the first drive waveform generation circuit 7, and generate and output a correction waveform (a drive waveform that increases the voltage value) at a drive frequency with a reduced ejection speed in the second drive waveform generation circuit 8. By implementing the generation and output of this correction waveform, it is possible to reduce the reduction in the ejection speed at the central part when the drive frequency changes due to the environmental temperature in each inkjet head and the printing device and the type of ink used, thereby improving the printing quality.

[0044] Use Figure 4 、 6 ~8, an example of the process of measuring the ejection speed of droplets in the inkjet head control device according to this embodiment will be described. Figure 6 The figure shown is for explaining an example of the process of measuring the ejection speed of droplets in the inkjet head control device according to this embodiment. Figure 7 and Figure 8 The figure shown is a flowchart example of the process of measuring the ejection speed of droplets in the inkjet head control device according to this embodiment.

[0045] The Vj adjustment control circuit 4 switches to an appropriate Vj correction mode according to the mode switching instruction from the host control device 1. First, the host control device 1 instructs the measurement conditions to the Vj adjustment control circuit 4. Here, the measurement conditions can be information such as the nozzle number No of the inkjet head for which the ejection speed is to be measured, the drive frequency (exact drive frequency or range of drive frequencies), the ink type, the nozzle temperature, etc. In the present embodiment, the measurement conditions include nozzle No. 0002, drive frequency (2 to 40 kHz, every 1 kHz), ink type (e.g., fixed), nozzle temperature (e.g., fixed at 25 ).

[0046] In step S51, the measurement conditions are loaded from the host control device 1 to the Vj adjustment control circuit 40. In step S52, the Vj adjustment control circuit 4 determines the inkjet head with nozzle No. 0002 for measuring the ejection speed based on the measurement conditions and transitions to step S53. Then, in step S53, the Vj adjustment control circuit 4 performs the camera observation position adjustment process. In the camera observation position adjustment process, the droplet observation device (camera) 6 is mechanically moved to a position where the droplets of the second droplet ejection device 14 can be observed. Then, after removing the medium, a second drip tray for receiving droplets is prepared. Here, since the drip tray is usually in the same position as the medium, it can also be a method of mechanically moving the inkjet head to a position deviated from the medium and setting it at a certain position on the drip tray.

[0047] Next, the second LED 47 is turned ON (connected), an image is acquired by the droplet observation device 6, the nozzle surface of the second droplet ejection device 14 is discriminated, and after discriminating the nozzle surface, the distance from the nozzle surface to the medium gap amount in the nozzle specifications (e.g., 1 mm) is prepared as a determination line for image processing. For the measurement of the ejection speed, the ejection speed can be calculated by how long it takes to reach a distance of 1 mm from the nozzle surface. In addition, the second LED 47 is turned ON (connected) or OFF (disconnected) synchronously with the drive frequency, making it easier for the camera to observe.

[0048] In addition, regarding the delay time of the second LED 47, it will be described using the drive waveform example described later Figure 11 . The so-called delay time of 0 means that at the moment of 0 Figure 11 in , the drive waveform still maintains the intermediate potential unchanged. In the image of the camera at this delay time, droplets cannot be confirmed on the nozzle surface. For example, the nozzle can also be of a stacked piezoelectric type structure. In Figure 11 from 8 to 9 Around is the moment when droplets are seen on the nozzle surface. This time (this delay time) is designated as t1. On the other hand, if the delay time for the droplets to reach the 1 mm line is t2, the ejection speed v1 is calculated by the following formula (1).

[0049] Formula (1)

[0050] In addition, for an appropriate ejection speed, although the appropriate speed varies depending on whether it is in an inkjet head (e.g., a stacked piezoelectric structure) or due to differences in the specifications of the liquid chamber configuration, as long as the variation is within the range of ±15 to 20%, it can be said that the image quality is not inferior. In the present embodiment, if the ejection speed is within ±20% of the reference speed, it is determined as OK (appropriate) and processing is performed.

[0051] Next, in step S54, the Vj adjustment control circuit 4 performs ejection processing from the nozzles of all ch (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 preliminarily confirming whether droplets can be ejected from the nozzles of all ch (channels). In step S55, the Vj adjustment control circuit 4 checks whether droplets are ejected from the nozzles of all channels. If no droplets are ejected from the nozzles of all channels (step S55: No), the Vj adjustment control circuit 4 proceeds to step S56 and checks whether the wiping count is 3 or more.

[0052] If the wiping count is less than 3 (step S56: No), the Vj adjustment control circuit 4 proceeds to step S57, refills the ink, and performs wiping to adjust the meniscus of the nozzles of each channel. Then, it returns to step S55. When droplets are ejected from the nozzles of all channels (step S55: Yes), and when the wiping count is 3 or more (step S56: Yes), the processing proceeds to step S58, and the Vj adjustment control circuit 4 ejects droplets only from one side of the nozzles of the channels that can eject droplets. At this time, the drive frequency can be adjusted by 1 kHz starting from a low frequency (e.g., 2 kHz). For example, the Vj adjustment control circuit 4 first ejects droplets from the nozzles of one 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. The details of the measurement processing of the ejection speed of the droplets will be described later.

[0053] Next, in step S60, the Vj adjustment control circuit 4 determines whether the measured injection speed is within the specified speed. If the measured injection speed is within the specified speed (step S60: Yes), then in step S64, the Vj adjustment control circuit 4 stores the voltage value in the memory 5. On the other hand, if the measured injection speed is not within the specified speed (step S60: No), then the Vj adjustment control circuit 4 proceeds to step S61 and determines whether the measured injection speed is higher than the specified speed. If the measured injection speed is higher than the specified speed (step S61: Yes), then the Vj adjustment control circuit 4 proceeds to step S63 to reduce the drive voltage. The step voltage for reducing the drive voltage depends on the nozzle specifications and can be, for example, about 0.1 to 0.2 V. If the measured injection speed is equal to or less than the specified speed (step S61: No), then the Vj adjustment control circuit 4 proceeds to step S62 and increases the drive voltage.

[0054] After the processes in steps S62 and S63 are executed, the process returns to step S60. After the process in step S64 is executed, the Vj adjustment control circuit 4 proceeds to step S65 and determines whether the measurement of the injection speed has been completed for all the nozzles in the injectable channels. If the measurement of the injection speed has not been completed for all the nozzles in the injectable channels (step S65: No), the process returns to step S58, and if the measurement of the injection speed has been completed for all the nozzles in the injectable channels (step S65: Yes), the measurement of the injection speed ends.

[0055] Next, an example of the detailed method for measuring the injection speed in step S59 of Figures 9 - 12 will be described. Figure 7 An example of the detailed method for measuring the injection speed in step S59 of Figures 9 - 12 FIG. shows an example of a diagram for explaining the measurement process of the injection speed in the liquid injection device according to the present embodiment.

[0056] In the present embodiment, the Vj adjustment control circuit 4 measures the injection speed using the droplet observation device 6. The droplet state of the droplets ejected from the nozzle exists in Figure 9 and Figure 10 shown in two ways. One way is that there is one droplet in the acquired image. The other way is that there are two or more droplets in the acquired image. Further, in the case of automatically measuring the injection speed of the droplets, the Vj adjustment control circuit 4 binarizes the acquired image. By binarizing the image, the area of the droplet is set to 1 within the image area, and the other areas are set to 0, so that the distance between the droplets can be calculated.

[0057] First, as Figure 11 shown, the method for measuring the injection speed in the case where there is one droplet in the acquired image will be described. The droplet observation device 6 has a delay time a ( ) Obtain an image. Next, the droplet observation device 6 obtains an image with a delay time of a + b ( ) Obtain an image. Then, the droplet observation device 6 overlaps and depicts the previously obtained image (the former image) through an or (logical OR) process and then obtains the image. Thus, the droplet observation device 6 can calculate the distance n (mm) between two droplets based on the pixel value = m of the two droplets in the image, and thus can obtain the ejection speed of the droplets .

[0058] Next, as Figure 12 shown, the method for measuring the ejection speed when there are two or more droplets in the obtained image will be described. For example, the droplet observation device 6 calculates the ejection speed with respect to the two lower droplets existing in the obtained image. As Figure 12 shown, the period w between droplet B and droplet C is w = 1 / driving frequency. In addition, the distance between droplet B and droplet C is q (mm) based on the pixel values of two points = p. Thus, the droplet observation device 6 can to obtain the ejection speed.

[0059] Figure 13 shown is a diagram of an example of the ejection speed when the inkjet head (No.0001, 0002) is driven with a constant driving waveform in the inkjet head control device according to the present embodiment. Figure 14 shown is a diagram of an example of the voltage value mapping for correcting the driving waveform of the inkjet head in the inkjet head control device according to the present embodiment. Figure 15 shown is a diagram of an example of the driving waveform of the inkjet head (No.0001) in the inkjet head control device according to the present embodiment. Figure 16 shown is a diagram of an example of the driving waveform of the inkjet head (No.0002) in the inkjet head control device according to the present embodiment. Figure 17 shown is a diagram of an example of the corrected ejection speed in the inkjet head control device according to the present embodiment.

[0060] Without correcting the voltage value of the driving waveform, as Figure 13 shown, the end portion of the inkjet head is Figure 1 and Figure 2 shown frequency characteristics. In addition, due to the influence of voltage drop in the piezoelectric power supply line and the like, the ejection speed at the central portion of the inkjet head is lower than that at the end portion. Figure 14 shown voltage value mapping is in Figure 4 shown configuration of the inkjet head control device 2, and Figure 13The ejection speed of the inkjet head shown is adjusted to the voltage value mapping within the specified ejection speed range of the inkjet head. In the present embodiment, the voltage value mapping represents the voltage value for each drive frequency and each channel at a certain ink type and nozzle temperature. In addition, for the channels of the nozzles, the nozzles of the driven channels are divided into three, and the voltage (p-p) of the drive waveform at each 1 kHz of the drive frequency is described. In addition, what supplements the voltage value mapping shown in Figure 14 is that the exemplified voltage value mapping shows three voltage values for the end portions (1 to n1ch), the end portions (n2 + 1 to nch), and the central portion (n1 + 1 to n2ch) at each nozzle No, ink type, and nozzle temperature at each drive frequency (the highest drive frequency in the nozzle specifications per 1 kHz).

[0061] Although it also depends on the characteristics of the inkjet head, the tendency most often observed is that the ejection speed of the nozzles of the channels in the central portion becomes slower and the voltage value becomes higher, and the ejection speed of the nozzles of the channels in the end portions is faster and the voltage value is lower compared to the nozzles of the channels in the central portion. Therefore, the reduction in the ejection speed of the nozzles of the channels in the central portion and the voltage values of the end portions (for example, 1 to n1ch) and the end portions (for example, n2 + 1 to nch) are the same, and two voltage values, namely the end portion and the central portion, can be used.

[0062] For example, if three more drive waveform generation circuits and analog switches ASW as shown in Figure 4 and Figure 5 are added to each channel, then the three voltage values as shown in Figure 14 can be selected and set. In the present embodiment, for the sake of illustration, an example is described with the minimum configuration having two drive waveform generation circuits and analog switches ASW in each channel.

[0063] Figure 5 The waveform selection control circuit 33 shown in order to switch between two drive waveforms sets the voltage values of the end portions of the nozzles (the voltage values of 1 to n1ch and n2 + 1 to nch) of the Figure 14 nozzle to the same voltage value, thereby setting two drive voltages, namely the voltage value of the central portion (n1 + 1 to n2ch) and the voltage value of the end portion. Figure 15 and Figure 16 are examples of drive waveforms and are made based on the data in the drive waveform data table example shown in Figure 14 . In this example, the drive waveform is generated in such a way that the Vp-p of the drive voltage increases sequentially from slow to fast in accordance with the ejection speed shown in Figure 13 . By driving the drive voltages at each nozzle No and each drive frequency with a plurality of corrected voltages, the variation in the ejection speed can be reduced as in the example of the corrected ejection speed shown in Figure 17 , and the printing quality can be improved.

[0064] Here, Figure 4 , 5 , 14, an example of the method for setting the drive voltage in the normal drive mode will be described.

[0065] First, in step S1, a printing job menu is sent from the host control device 1 to the inkjet head control device 2. Here, the printing job menu indicates a job of printing k lines at a drive frequency of 2 kHz and m lines at a drive frequency of 40 kHz in the first and second liquid ejection devices 13 and 14. The printing job menu is read into the Vj adjustment control circuit 4.

[0066] Next, in step S2, when driving the first droplet ejection device 13 at a drive frequency of 2 kHz, V4 (= V6) is set for the first drive waveform generation circuit 7 for the end portion of the first droplet ejection device 13, and V5 is set for the second drive waveform generation circuit 8 for the central portion of the first droplet ejection device 13. Here, V4 (= V6) is the voltage value of the nozzles of 1 to n1ch and n2 + 1 to nch (end portion) of the first droplet ejection device 13. In addition, V5 is the voltage value of the nozzles of n1 + 1 to n2ch (central portion) of the inkjet head.

[0067] In addition, in step S2, when driving the second droplet ejection device 14 at a drive frequency of 4 kHz, Vk + 3 (= Vk + 6) is set for the third drive waveform generation circuit 10 for the end portion of the second droplet ejection device 14, and Vk + 4 is set for the fourth drive waveform generation circuit 11 for the central portion of the second droplet ejection device 14. Here, Vk + 3 (= Vk + 5) is the voltage value of the nozzles of 1 to n1ch and n2 + 1 to nch (end portion) of the second droplet ejection device 14. In addition, Vk + 4 is the voltage value of the nozzles of n1 + 1 to n2ch (central portion) of the second droplet ejection device 14.

[0068] In step S3, when printing k lines through the droplet ejection device 30 at a drive frequency of 2 kHz, Figure 5 To explain, among the nozzles at the end portion (nozzles of 1 to n1ch and n2 + 1 to nch) of the droplet ejection device 30, the analog switch ASW connected to the first drive waveform generation circuit 31 is turned on for the waveform selection control circuit 33, and the drive waveform generated by the first drive waveform generation circuit 31 is applied to the piezoelectric element. Among the nozzles in the central portion (n + 1 to n2ch) of the droplet ejection device 30, the analog switch ASW connected to the drive waveform generation circuit 32 is turned on for the waveform selection control circuit 33, and the drive waveform generated by the second drive waveform generation circuit 32 is applied to the piezoelectric element.

[0069] In step S4, when driving the nozzles of the first droplet ejection device 13 at a driving frequency of 40 kHz, V118 (= V120) is set in the first driving waveform generation circuit 7 (for the ends), and V119 is set in the second driving waveform generation circuit 8 (for the central part). Further, when driving the nozzles of the second droplet ejection device 14 at a driving frequency of 40 kHz, Vk + 117 (Vk + 119) is set in the third driving waveform generation circuit 10 (for the ends), and Vk + 118 is set in the fourth driving waveform generation circuit 11 (for the central part). Here, V118 is the voltage value of the nozzles of channels 1 to n1 and n2 + 1 to n of the ends of the first droplet ejection device 13, and V119 is the voltage value of the channels n1 + 1 to n2 of the central part of the first droplet ejection device 13. Further, here, Vk + 117 is the voltage value of the nozzles of channels 1 to n1 and n2 + 1 to n of the ends of the second droplet ejection device 14, and Vk + 118 is the voltage value of the channels n1 + 1 to n2 of the central part of the second droplet ejection device 14.

[0070] In step S5, when printing m rows by the first and second droplet ejection devices 13 and 14 at a driving frequency of 40 kHz, a driving waveform is applied to the piezoelectric elements in the same manner as in step S3.

[0071] Figure 18 and Figure 19 Shown is a schematic diagram of an example of the overall structure of an inkjet printer which is an example of the liquid ejection device according to the present embodiment. Specifically, Figure 18 is a perspective three-dimensional view of the inkjet printer 100, Figure 19 is a perspective side view of the inkjet printer 100.

[0072] As Figure 18 and Figure 19 shown, 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 that can move in the main scanning direction inside the device main body, a recording head 102 (droplet ejection devices 13 and 14 such as inkjet heads) mounted on the carriage 101, a printing mechanism unit composed of an ink cartridge 103 that supplies ink to the recording head 102, and the like. Below the device main body of the inkjet printer 100, a paper feed cassette (or a paper feed tray may also be used) 104 can be detachably installed, and the paper feed cassette can load a plurality of recording media such as sheets of paper P from the front side. Further, in the inkjet printer 100, a manual tray 105 for manually feeding the sheet P can be opened.

[0073] The inkjet printer 100 takes in the paper P supplied from the paper supply cassette 104 or the manual tray 105, and after recording the required image through the above-mentioned printing mechanism unit, discharges it to the paper discharge tray 106 installed on the rear side. In addition, hereinafter, the case where the recording medium is the paper P will be described as an example, but as the recording medium, in addition to paper, as long as it is a sheet-like material such as a film or plastic and is a material that is the object of image formation output, it can be adopted.

[0074] In addition, the printing mechanism unit holds the carriage 101 so as to be slidable in the main scanning direction (perpendicular to the paper surface) through the guide rod 107 and the sub-guide rod 108 which are guide members spanning the left and right side plates. The carriage 101 is equipped with a liquid ejection unit 440 in which the recording head 102 and the ink tank 441 are integrated. The recording head 102 mounted on the liquid ejection unit 440 ejects ink droplets of various colors such as yellow, cyan, magenta, and black. A plurality of ink ejection ports for ejecting these various colors of ink are arranged in a direction (sub-scanning direction) intersecting the main scanning direction, and the ink ejection ports face downward.

[0075] Each ink cartridge 103 for supplying ink of various colors to the recording head 102 is detachably mounted on the carriage 101. In addition, the ink cartridge 103 has a vent port communicating with the atmosphere above it, a supply port for supplying ink to the recording head 102 below it, and a porous body filled with ink inside. Through the capillary force of the porous body, the ink supplied to the recording head 102 is maintained at a slight negative pressure. Also, in the present embodiment, although the case where the recording head 102 is provided for each color is taken as an example, one recording head having nozzles for ejecting ink of various colors can also be used.

[0076] The rear side (downstream side in the paper conveyance direction) of the carriage 101 is slidably mounted on the 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 the drive pulley 110 and the driven pulley 111 rotated and 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 rotation of the main scanning motor 109.

[0077] On the other hand, in order to convey the paper placed in the paper supply 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 front roller 118 are provided. The paper feed roller 113 and the friction pad 114 separate and supply the paper P from the paper supply cassette 104, and the guide member 115 guides the separated and supplied paper P.

[0078] The conveying roller 116 reverses and conveys the supplied paper P. The conveying roller 117 is pressed against the outer peripheral surface of the conveying roller 116, and the front end roller 118 defines the ejection angle of the paper P from the conveying roller. In addition, the conveying roller 116 is driven to rotate via a gear train by a sub-scanning motor.

[0079] A printing receiving member 119 as a paper guiding member is provided, and guides the paper P ejected by the conveying roller 116 to the lower side of the liquid ejection head corresponding to the moving range in the main scanning direction of the carriage 101. On the downstream side in the paper conveying direction of the printing receiving member 119, a rotatably driven conveying roller 120 and a spur wheel 121 for ejecting the paper P in the paper discharging direction are provided. Further, a paper discharging roller 122, a spur wheel 123 for discharging the paper P to the paper discharge tray 106, and guide members 124, 125 forming a paper discharge path are arranged.

[0080] When recording an image on the paper P, the controller of the inkjet printer 100 drives the recording head 102 according to the image signal while moving the carriage 101, thereby ejecting ink onto the stopped paper P to record the amount of one scan. Then, the controller of the inkjet printer 100 performs recording of the next line after conveying the paper P by a predetermined amount. In addition, when the controller of the inkjet printer 100 receives a recording end signal or a signal that the rear end of the paper P has reached the recording area, the recording operation ends and the paper P is discharged.

[0081] The recording head 102 includes a piezoelectric element as a driving element for driving the plurality of nozzles provided 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 an ejection force for ejecting ink (an example of droplets) from the plurality of nozzles respectively. By applying a predetermined driving waveform to the piezoelectric element, ink is ejected from each nozzle. That is, the recording head 102 (an example of a liquid ejection head) has a plurality of nozzles and a piezoelectric element (piezo), and the piezoelectric element is provided for each of the nozzles and is applied with a driving signal (driving waveform) to eject ink from the nozzle.

[0082] In addition, a maintenance and recovery device 126 for recovering ejection defects of the recording head 102 is arranged at a position on the right end side in the moving direction of the carriage 101 and deviated from the recording area. The maintenance and recovery device 126 includes a cover unit, a suction unit, and a cleaning unit. During printing standby, the carriage 101 moves to the side of the maintenance and recovery device 126, and the recording head 102 is covered by the cover unit. Therefore, the ejection port portion is kept in a wet state, thereby preventing ejection defects due to ink drying.

[0083] In addition, during the recording period, the recording head 102 ejects ink that is not related to recording into the maintenance and recovery device 126 (idle ejection), so as to keep the ink viscosity constant at all ejection ports to maintain stable ejection performance. Specifically, in the case of ejection failure or the like, the cover unit seals the ejection ports (nozzles) of the recording head 102, and the suction unit sucks out air bubbles and the like together with the ink from the ejection ports through the tube. Then, the ink, dust, etc. adhering to the ejection port surface are removed by the cleaning mechanism, and the ejection failure is restored. In addition, the sucked ink is discharged into the waste ink reservoir provided at the lower part of the main body, and is absorbed and held by the ink absorber inside the waste ink reservoir.

[0084] In addition, the liquid ejection heads such as the recording head 102 are not limited to the pressure generating units used. For example, in addition to the piezoelectric actuators (layered piezoelectric elements can also be used) described in the above embodiments, thermal actuators such as heating resistive elements and electrostatic actuators composed of a diaphragm and counter electrodes can also be used.

[0085] In addition, in the terms of this application, image formation, recording, printing, writing, printing, molding, etc. are all synonyms.

[0086] In this embodiment, the liquid ejection unit refers to a component in which functional parts and mechanisms are integrated on the liquid ejection head, and is an aggregate of parts related to the ejection of liquid. For example, the liquid ejection unit 440 includes at least one of the ink cartridges 103 and other printhead cartridges, the carriage 101, the supply mechanism, the maintenance and recovery device 126, and the main scanning movement mechanism combined with the liquid ejection head 102.

[0087] Here, integration means that, for example, the liquid ejection head and functional parts and mechanisms are fixed to each other by fastening, bonding, clamping, etc., and one is held relative to the other so as to be movable. In addition, the liquid ejection head and functional parts and mechanisms can also be configured to be detachable from each other.

[0088] For example, as the liquid ejection unit, there is one formed by integrating the liquid ejection head and the printhead cartridge. In addition, there is one in which the liquid ejection head and the printhead cartridge are integrated by connecting them to each other through a hose or the like. Here, a unit containing a filter can also be added between the printhead cartridge and the liquid ejection head of these liquid ejection units.

[0089] In addition, as the liquid ejection unit, there is a device formed by integrating the liquid ejection head and the carriage 101.

[0090] In addition, as the liquid ejection unit, there is also one in which the liquid ejection head is movably held on a guide member constituting a part of the main scanning movement mechanism to integrate the liquid ejection head and the main scanning movement mechanism. In addition, there is one formed by integrating the liquid ejection head, the carriage 101, and the main scanning movement mechanism.

[0091] In addition, as a liquid ejection unit, there is also a configuration in which a cover member that is a part of the maintenance and recovery device 126 is fixed to the carriage 101 on which the liquid ejection head is mounted, so that the liquid ejection head, the carriage 101, and the maintenance and recovery device 126 are integrated.

[0092] In addition, as a liquid ejection unit, there is a configuration in which a hose is connected to a liquid ejection head in which a nozzle tank or a flow path component is mounted, so that the liquid ejection head and the supply mechanism are integrated. Through this hose, the liquid from the liquid storage source is supplied to the liquid ejection head.

[0093] The main scanning movement mechanism also includes a guide member alone. In addition, the supply mechanism also includes a hose alone and a loading unit alone.

[0094] In addition, in the present application, a liquid ejection device such as an inkjet printer 100 is a device that includes a liquid ejection head or a liquid ejection module and drives the liquid ejection head to eject a liquid. In the liquid ejection device, it is not only a device that can eject a liquid onto an object to which the liquid can adhere, but may also include a device that ejects a liquid into the air or into a liquid.

[0095] The liquid ejection device may further include a mechanism for feeding, transporting, and discharging a sheet of an object to which a liquid can adhere, as well as other pre-processing devices, post-processing devices, and the like.

[0096] For example, as a liquid ejection device, there are an image forming device that is a device for ejecting ink liquid to form an image on a sheet of paper, and a three-dimensional modeling device (3D modeling device) that ejects a modeling liquid into a powder layer in which a powder is formed layer by layer in order to model a three-dimensional object (3D object).

[0097] In addition, the liquid ejection device is not limited to visualizing meaningful images such as characters and graphics by ejecting a liquid. For example, it also includes forming a pattern that has no meaning in itself and modeling a three-dimensional image.

[0098] The above-mentioned substance to which a liquid can adhere refers to a substance to which a liquid can adhere at least temporarily, and refers to a substance that adheres after adhesion and penetrates after adhesion. As a specific example, it may be a recording medium such as paper, recording paper, recording sheet, film, cloth, etc., an electronic component such as an electronic substrate and a piezoelectric element, and a medium such as a powder layer (powder coating), an organ model, and an inspection part. As long as there is no special limitation, it includes all substances to which a liquid can adhere.

[0099] The material of the above-mentioned substance to which a liquid can adhere only needs to be such that a liquid can adhere to it even temporarily, such as paper, silk, fiber, fabric, leather, metal, plastic, glass, wood, ceramic, etc.

[0100] In addition, the liquid only needs to be a liquid having a viscosity and surface tension that can be ejected from the liquid ejection head, and there is no particular limitation, but it is preferably 30 MPa·s or less in viscosity at normal temperature and pressure or under heating and cooling. More specifically, it includes solvents such as water and organic solvents, colorants such as dyes and pigments, functional imparting materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium, and edible materials such as natural pigments, etc., in the form of solutions, suspensions, latexes, etc., and they can be used for applications such as inkjet inks, surface treatment liquids, liquids for forming components of electronic components and light-emitting elements and patterns of electronic circuit resist layers, and materials liquids for three-dimensional modeling, etc.

[0101] In addition, the liquid ejection device has a liquid ejection head and a device for relative movement of the liquid-attachable object, but is not limited thereto. As specific examples, it includes a serial device that moves the liquid ejection head, a line type device that does not move the liquid ejection head, etc.

[0102] In addition, as the liquid ejection device, there is also a treatment liquid coating device that discharges the treatment liquid onto the paper surface for the purpose of surface modification of the paper, etc., and an ejection granulation device that granulates fine particles of the raw material by ejecting a composition liquid in which the raw material is dispersed into a solution through a nozzle, etc.

[0103] Thus, according to the liquid ejection device according to the present embodiment, it is possible to reduce the difference in ejection speed between the central portion and the end portion of the nozzle row, including variations in the drive frequency of the nozzles included in the liquid ejection head, variations between liquid ejection heads, the ambient temperature in the liquid ejection device such as a printing device, and non-uniformity in the types of ink liquids used, and thus it is possible to improve the printing quality.

[0104] In addition, the program executed by the liquid ejection device of the present embodiment is provided by being pre-loaded into a ROM (Read Only Memory), etc. The program executed by the liquid ejection device of the present embodiment can also be configured to be recorded on a computer-readable recording medium such as a CD-ROM, a floppy disk (FD), a CD-R, a DVD (Digital Versatile Disc), etc. in the form of an installable or executable file for providing.

[0105] Furthermore, in addition, it can also be configured to store the program executed by the liquid ejection device of the present embodiment on a computer connected to a network such as the Internet and provide it by downloading via the network. In addition, the program executed by the liquid ejection device of the present embodiment can also be provided or distributed via a network such as the Internet.

[0106] The program executed by the liquid ejection device according to the present embodiment is composed of modules including the above-described respective units (drive signal output unit, voltage information acquisition unit, control unit). As actual hardware, a processor such as a CPU (Central Processing Unit) reads the program from the above-described ROM and executes it, so that the above-described respective units are loaded onto the main storage device, and the drive signal output unit, voltage information acquisition unit, and control unit are generated on the main storage device.

[0107] An embodiment of the present invention is described as follows, for example.

[0108] <1>

[0109] A liquid ejection head driving device that drives a liquid ejection head having a plurality of nozzles for ejecting a liquid according to an input drive signal, characterized by including: a drive signal output unit that generates the drive signal based on voltage information related to a voltage applied to a piezoelectric element in the nozzle and outputs the drive signal to the liquid ejection head; a voltage information acquisition unit that acquires appropriate voltage information within a specified range of the ejection speed based on 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 storage unit that stores the appropriate voltage information in association with identification information of the nozzle and a 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.

[0110] <2>

[0111] The liquid ejection head driving device according to <1>, characterized by further including the droplet speed measurement unit, the droplet speed measurement unit having a camera that measures the droplets, the camera being movable relative to the liquid ejection head and capable of measuring the ejection speed for each nozzle.

[0112] <3>

[0113] The liquid ejection head driving device according to <1> or <2>, characterized by including: the liquid ejection head driving device has a normal driving mode and a calibration mode, and when transitioning to the calibration mode, the voltage information acquisition unit acquires the appropriate voltage information based on the droplet speed information and the voltage information.

[0114] <4>

[0115] The liquid ejection head driving device according to any one of <1> to <3>, characterized in that: the voltage information acquisition unit acquires the appropriate voltage information for each liquid ejection head.

[0116] <5>

[0117] The liquid ejection head driving device according to any one of <1> to <4>, characterized in that: the voltage information acquisition unit acquires the appropriate voltage information for each temperature around the liquid ejection head.

[0118] <6>

[0119] The liquid ejection head driving device according to any one of <1> to <5>, characterized in that: the voltage information acquisition unit acquires the appropriate voltage information for each type of ink liquid ejected from the liquid ejection head.

[0120] <7>

[0121] A liquid ejection head driving system having a liquid ejection head driving device and a droplet velocity measurement unit, the liquid ejection head driving device driving a liquid ejection head having a plurality of nozzles for ejecting a liquid according to an input driving signal, the droplet velocity measurement unit being movable relative to the liquid ejection head and provided with a camera capable of measuring the ejection velocity of the liquid for each nozzle of the liquid ejection head, the liquid ejection head driving system being characterized in that: the liquid ejection head driving device includes: a driving signal output unit that generates the driving signal based on voltage information related to the voltage applied to the piezoelectric element in the nozzle and outputs the driving signal to the liquid ejection head; a voltage information acquisition unit that acquires the appropriate voltage information for which the ejection velocity falls within a specified range based on the droplet velocity information acquired from the droplet velocity measurement unit that measures the ejection velocity of the droplets ejected from the liquid ejection head and the voltage information; a storage unit that stores the appropriate voltage information in correspondence with the identification information of the nozzle and the driving frequency of the nozzle; and a control unit that acquires the appropriate voltage information corresponding to the identification information and the driving frequency from the storage unit and causes the driving signal output unit to output the driving signal based on the appropriate voltage information, and the droplet velocity measurement unit can communicate with the liquid ejection head driving device.

[0122] <8>

[0123] A liquid ejecting device, comprising: a liquid ejecting head having a plurality of nozzles for ejecting liquid according to an input drive signal; a drive signal output section that generates the drive signal based on voltage information related to a voltage applied to a piezoelectric element in the nozzle and outputs the drive signal to the liquid ejecting head; a voltage information acquisition section that acquires appropriate voltage information within a prescribed range of the ejection speed based on droplet speed information acquired from a droplet speed measurement unit that measures the ejection speed of droplets ejected from the liquid ejecting head and the voltage information; a storage section that stores the appropriate voltage information in association with identification information of the nozzle and a drive frequency of the nozzle; and a control section that acquires the appropriate voltage information corresponding to the identification information and the drive frequency from the storage section and causes the drive signal output section to output the drive signal based on the appropriate voltage information.

[0124] <9>

[0125] A liquid ejecting head drive method executed by a liquid ejecting head drive device that drives a liquid ejecting head having a plurality of nozzles for ejecting liquid according to an input drive signal, comprising: a step of generating the drive signal based on voltage information related to a voltage applied to a piezoelectric element in the nozzle and outputting the drive signal to the liquid ejecting head; a step of acquiring appropriate voltage information within a prescribed range of the ejection speed based on droplet speed information acquired from a droplet speed measurement unit that measures the ejection speed of droplets ejected from the liquid ejecting head and the voltage information; and a step of acquiring the appropriate voltage information corresponding to the identification information and the drive frequency from a storage section 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.

[0126] <10>

[0127] A program product, characterized in that it causes a computer to function as the following parts: a drive signal output unit that generates the drive signal based on voltage information related to a voltage in a piezoelectric element of a nozzle included in a liquid ejection head and outputs the drive signal to the liquid ejection head, the liquid ejection head having a nozzle that ejects liquid according to an input drive signal; a voltage information acquisition unit that acquires appropriate voltage information within a specified range of the ejection speed based on 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; and a control unit that acquires the appropriate voltage information corresponding to the identification information and the drive frequency of the nozzle from a storage unit that stores the appropriate voltage information in association with the identification information 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.

[0128]

Symbol Explanation

[0129] 1 Host control device

[0130] 2 Inkjet head control device

[0131] 3 Operation mode switching circuit

[0132] 4 Vj adjustment control circuit

[0133] 5 Memory

[0134] 6 Droplet observation device

[0135] 7, 8, 10, 11, 31, 32 Drive waveform generation circuit

[0136] 9, 12, 33 Waveform selection control circuit

[0137] 13, 14, 30 Droplet ejection device

Claims

1. A liquid ejection head driving device for driving a liquid ejection head having a plurality of nozzles for ejecting liquid according to an input drive signal, characterized in that include: a drive signal output section that generates the drive signal based on voltage information related to a voltage applied to a piezoelectric element of the nozzle and outputs the drive signal to the liquid ejecting head; a voltage information acquisition unit that acquires appropriate voltage information for causing the ejection speed to fall within a predetermined range based on droplet speed information acquired from a droplet speed measurement unit that measures an ejection speed of droplets ejected from the liquid ejection head and the voltage information; a storage unit for storing the appropriate voltage information in association with the identification information of the nozzle and the driving frequency of the nozzle; as well as The control unit acquires the appropriate voltage information corresponding to the identification information and the driving frequency from the storage unit, and causes the driving signal output unit to output the driving signal based on the appropriate voltage information.

2. The liquid ejecting head driving device according to claim 1, wherein: Also includes the droplet velocity measurement unit, The droplet velocity measurement unit has a camera for measuring the droplet, The camera is movable relative to the liquid ejecting head and is capable of measuring the ejection speed for each of the nozzles.

3. The liquid ejection head driving device according to claim 1 or 2, characterized in that include: The liquid ejecting head driving device has a normal driving mode and a calibration mode. When shifting to the correction mode, the voltage information acquisition section acquires the appropriate voltage information based on the droplet velocity information and the voltage information.

4. The liquid ejecting head driving device according to claim 1, wherein: The voltage information acquisition section acquires the appropriate voltage information for each of the liquid ejecting heads.

5. The liquid ejecting head driving device according to claim 1, wherein: The voltage information acquisition section acquires the appropriate voltage information for each temperature around the liquid ejecting head.

6. The liquid ejecting head driving device according to claim 1, wherein: The voltage information acquisition section acquires the appropriate voltage information for each type of ink ejected from the liquid ejecting head.

7. A liquid ejection head driving system having a liquid ejection head driving device and a liquid droplet velocity measuring unit, wherein the liquid ejection head driving device drives a liquid ejection head having a plurality of nozzles for ejecting liquid according to an input drive signal, the liquid droplet velocity measuring unit is movable relative to the liquid ejection head and is provided with a camera capable of measuring the ejection velocity of the liquid for each nozzle of the liquid ejection head, wherein the liquid ejection head driving system is characterized in that: The liquid ejection head driving device comprises: a drive signal output section that generates the drive signal based on voltage information related to a voltage applied to a piezoelectric element of the nozzle and outputs the drive signal to the liquid ejecting head; a voltage information acquisition unit that acquires appropriate voltage information for causing the ejection speed to fall within a predetermined range based on droplet speed information acquired from a droplet speed measurement unit that measures an ejection speed of droplets ejected from the liquid ejection head and the voltage information; a storage unit for storing the appropriate voltage information in association with the identification information of the nozzle and the driving frequency of the nozzle; as well as a control unit that acquires the appropriate voltage information corresponding to the identification information and the driving frequency from the storage unit, and causes the driving signal output unit to output the driving signal based on the appropriate voltage information, The liquid droplet velocity measurement unit is capable of communicating with the liquid ejection head driving device.

8. A liquid injection device, characterized in that include: a liquid ejecting head having a plurality of nozzles for ejecting liquid according to an input drive signal; a drive signal output section that generates the drive signal based on voltage information related to a voltage applied to a piezoelectric element of the nozzle and outputs the drive signal to the liquid ejecting head; a voltage information acquisition unit that acquires appropriate voltage information for causing the ejection speed to fall within a predetermined range based on droplet speed information acquired from a droplet speed measurement unit that measures an 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 driving frequency of the nozzle, and The control unit acquires the appropriate voltage information corresponding to the identification information and the driving frequency from the storage unit, and causes the driving signal output unit to output the driving signal based on the appropriate voltage information.

9. A liquid ejection head driving method performed by a liquid ejection head driving device for driving a liquid ejection head having a plurality of nozzles for ejecting liquid according to an input drive signal, characterized in that include: generating the driving signal based on voltage information related to a voltage applied to a piezoelectric element of a nozzle, and outputting the driving signal to the liquid ejecting head; A step of acquiring appropriate voltage information for causing the ejection speed to fall within a predetermined range based on droplet speed information acquired from a droplet speed measuring unit that measures an ejection speed of droplets ejected from the liquid ejection head and the voltage information; The step of acquiring the appropriate voltage information corresponding to the identification information and the driving frequency 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, and outputting the driving signal based on the appropriate voltage information.

10. A program product, characterized in that Enable the computer to perform the following functions: a drive signal output unit that generates the drive signal based on voltage information related to a voltage applied to a piezoelectric element of a nozzle of a liquid ejecting head and outputs the drive signal to the liquid ejecting head, the liquid ejecting head having a nozzle that ejects liquid according to the input drive signal; a voltage information acquisition unit that acquires appropriate voltage information for causing the ejection speed to fall within a predetermined range based on droplet speed information acquired from a droplet speed measurement unit that measures an ejection speed of droplets ejected from the liquid ejection head and the voltage information; A control unit obtains the appropriate voltage information corresponding to the identification information and the driving frequency 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, and causes the driving signal output unit to output the driving signal based on the appropriate voltage information.

Images