JP2020082640A - Inkjet printer and method for controlling inkjet printer - Google Patents

Abstract

To provide an on-demand inkjet printer in which the increase of the viscosity of ink within a nozzle having stopped ejection of ink droplets during printing can be effectively suppressed.SOLUTION: The inkjet printer includes a piezo element 9 causing a nozzle 3a to eject ink droplet. When the drive frequency of the piezo element 9 when ink droplets are continuously ejected from the nozzle 3a at the shortest cycle is the maximum drive frequency, the nozzle 3a that has stopped ejection of ink droplets upon printing is the rest nozzles 3a, and the piezo element 9 causing the rest nozzle 3a to eject ink droplets is a first piezo element 9, then, when the inkjet printer drives the first piezo element 9 at a first frequency lower than the maximum drive frequency upon printing and drives the first piezo element 9 at the first frequency, the inkjet printer drives the first piezo element 9 a plurality of times at a resonance frequency of an inkjet head 3 to vibrate a meniscus M of the ink in the rest nozzle 3a.SELECTED DRAWING: Figure 2

Description

The present invention relates to an on-demand type inkjet printer. The present invention also relates to a control method for an on-demand type inkjet printer.

2. Description of the Related Art Conventionally, there is known an inkjet printer (inkjet recording apparatus) of a continuous type (a continuous ejection type) that prints by ejecting ink droplets from a nozzle by driving a piezo element (for example, see Patent Document 1). .. In the inkjet printer described in Patent Document 1, when the printing is stopped in which the ink droplets are not ejected from the nozzles, the ink droplets are ejected from the nozzles by driving the piezo element with a voltage equal to or lower than a threshold voltage required for forming the ink droplets. The ink meniscus is vibrated inside the nozzle so as not to do so. Therefore, in this inkjet printer, it is possible to prevent the clogging of the nozzles by suppressing an increase in the viscosity of the ink in the nozzles when printing is stopped.

JP, 57-61576, A

In the case of an on-demand type ink jet printer, there are nozzles that do not eject ink droplets at a predetermined timing even if printing is being performed on a print medium. Therefore, in the case of an on-demand ink jet printer, even during printing of the print medium, the viscosity of the ink in the nozzles that have stopped ejecting ink droplets increases, causing clogging of the nozzles, After that, when ejecting an ink droplet from this nozzle, there is a possibility that ejection failure of the ink may occur. Therefore, the inventor of the present application has made it possible to vibrate an ink meniscus in a nozzle that suspends discharge of ink droplets at a predetermined timing even when printing a print medium in an on-demand type inkjet printer. Are considering.

In this case, it is better to increase the driving frequency of the piezo element (that is, increase the driving frequency of the piezo element per unit time) and increase the vibration frequency of the ink meniscus in the nozzle per unit time. Since it was thought that the stirring effect of the ink in the ink was increased and the increase in the viscosity of the ink could be effectively suppressed, the inventors of the present application have found that when ink droplets are continuously ejected from the nozzle in the shortest cycle. It was studied to drive the piezo element at the maximum drive frequency, which is the drive frequency of the piezo element, to vibrate the meniscus of the ink in the nozzle that suspends ink droplet ejection at a predetermined timing during printing.

However, if the driving frequency of the piezo element is increased and the number of times the piezo element is driven per unit time is increased too much (that is, if the number of vibrations of the ink meniscus in the nozzle is increased per unit time), Although the stirring effect of the ink in the ink is enhanced, the piezo element generates heat, so that the ink is heated and the solvent of the ink evaporates, and conversely, the viscosity of the ink in the nozzle increases. It was revealed. That is, it was revealed by the inventors of the present application that the increase in the viscosity of the ink cannot be effectively suppressed even by simply increasing the number of times the piezo element is driven per unit time.

Therefore, an object of the present invention is to effectively suppress an increase in the viscosity of the ink in the nozzle that suspends the ejection of ink droplets at a predetermined timing during printing in an on-demand type inkjet printer. To provide a reliable inkjet printer. Further, an object of the present invention is to effectively suppress an increase in the viscosity of the ink in the nozzle that suspends the ejection of ink droplets at a predetermined timing during printing in an on-demand type inkjet printer. Another object of the present invention is to provide a method for controlling an inkjet printer.

In order to solve the above-mentioned problems, an inkjet printer of the present invention is an inkjet printer that ejects ink droplets for printing, in order to eject ink droplets from each of a plurality of nozzles that eject ink droplets and a plurality of nozzles. When an inkjet head having a plurality of ejection energy generating elements and a control unit for driving the ejection energy generating elements to eject ink droplets from the nozzles, and ink droplets are ejected continuously from the nozzle in the shortest cycle The maximum driving frequency is the drive frequency of the discharge energy generating element, and the nozzles that stop discharging ink droplets at a predetermined timing during printing are pause nozzles, and the discharge energy generating element for discharging ink droplets from the pause nozzles. Is the first ejection energy generating element, the control unit drives the first ejection energy generating element at a first frequency lower than the maximum driving frequency during printing to vibrate the meniscus of the ink in the pause nozzle, and When the first ejection energy generating element is driven at one frequency, the first ejection energy generating element is driven a plurality of times at the resonance frequency of the inkjet head to vibrate the meniscus in the pause nozzle.

Further, in order to solve the above-mentioned problems, a control method of an inkjet printer of the present invention has a plurality of nozzles for ejecting ink droplets and a plurality of ejection energy generating elements for ejecting ink droplets from each of the plurality of nozzles. A method for controlling an inkjet printer that includes an inkjet head and drives an ejection energy generating element to eject ink droplets from nozzles to perform printing, wherein ejection is performed when ink droplets are continuously ejected at the shortest cycle. The drive frequency of the energy generating element is set to the maximum drive frequency, the nozzle that suspends the ejection of ink droplets at a predetermined timing during printing is a pause nozzle, and the ejection energy generating element for ejecting ink droplets from the pause nozzle is Assuming that one ejection energy generating element is used, at the time of printing, the first ejection energy generating element is driven at a first frequency lower than the maximum driving frequency to vibrate the meniscus of the ink in the pause nozzle, and the first ejection energy is generated at the first frequency. When the energy generating element is driven, the first ejection energy generating element is driven a plurality of times at the resonance frequency of the inkjet head to vibrate the meniscus in the pause nozzle.

According to the present invention, when the first ejection energy generating element is driven at the first frequency lower than the maximum driving frequency, the first ejection energy generating element is driven a plurality of times at the resonance frequency of the inkjet head, and the ink in the pause nozzle is discharged. Is vibrating the meniscus. Therefore, in the present invention, when the first ejection energy generating element is driven at the first frequency, the amplitude of the vibration of the meniscus of the ink in the pause nozzle is effectively increased to improve the ink stirring effect in the pause nozzle. It becomes possible to raise.

Further, in the present invention, during printing, the first ejection energy generating element is driven at the first frequency lower than the maximum drive frequency to vibrate the meniscus of the ink in the pause nozzles. Therefore, the first ejection is performed at the first frequency. Even when the first ejection energy generating element is driven a plurality of times when the energy generating element is driven, the number of times of driving the first ejection energy generating element per unit time is set to one time at the maximum driving frequency of the first ejection energy generating element. It is possible to reduce the number of times the first ejection energy generating element is driven per unit time, when the first ejection energy generating element is driven each time.

Therefore, in the present invention, for example, the number of times of driving the first ejection energy generating element per unit time is the unit of the first ejection energy generating element when the first ejection energy generating element is driven once at the maximum driving frequency. If the number of times of driving per unit time is made the same, the heat generation amount of ink in the pause nozzle is made equal to the heat generation amount of ink in the pause nozzle when the first ejection energy generating element is driven once at the maximum drive frequency. At the same time, it becomes possible to enhance the effect of stirring the ink in the pause nozzle.

In the present invention, for example, the number of times the first ejection energy generating element is driven per unit time is the unit of the first ejection energy generating element when the first ejection energy generating element is driven once at the maximum driving frequency. If the number of vibrations is set to be smaller than the number of vibrations per time, and the same stirring effect as the stirring effect of ink in the pause nozzle when the first ejection energy generating element is driven once at the maximum driving frequency is obtained. While making the ink stirring effect in the pause nozzle the same as the ink stirring effect in the pause nozzle when the first ejection energy generating element is driven once at the maximum drive frequency, the heat generation amount of the ink in the pause nozzle Can be reduced.

As described above, in the present invention, the calorific value of the ink in the pause nozzle is made equal to the calorific value of the ink in the pause nozzle when the first ejection energy generating element is driven once at the maximum drive frequency, and the pause is achieved. It is possible to enhance the effect of stirring the ink in the nozzle, or to improve the effect of stirring the ink in the pause nozzle in the pause nozzle when the first ejection energy generating element is driven once at the maximum drive frequency. It is possible to reduce the heat generation amount of the ink in the pause nozzle while keeping the same effect of stirring the ink. Therefore, in the present invention, it is possible to effectively suppress the increase in the viscosity of the ink in the pause nozzle.

Further, in order to solve the above problems, the inkjet printer of the present invention is an inkjet printer that ejects ink droplets for printing, and ejects ink droplets from a plurality of nozzles that eject ink droplets and each of the plurality of nozzles. An inkjet head having a plurality of ejection energy generating elements and a plurality of meniscus vibrating elements that vibrate the meniscus of each ink in a plurality of nozzles, and a control unit that drives the ejection energy generating elements and the meniscus vibrating elements, the nozzle The maximum drive frequency is the drive frequency of the discharge energy generating element when the ink droplets are continuously discharged in the shortest cycle, and the nozzles that suspend the discharge of the ink droplets at the predetermined timing during printing are pause nozzles. When the meniscus vibrating element that vibrates the meniscus in the resting nozzle is the first meniscus vibrating element, the control unit drives the first meniscus vibrating element at the first frequency lower than the maximum driving frequency during printing to cause When the first meniscus vibrating element is driven at the first frequency while vibrating the meniscus, the first meniscus vibrating element is driven a plurality of times at the resonance frequency of the inkjet head to vibrate the meniscus in the pause nozzle. And

Furthermore, in order to solve the above problems, a method for controlling an inkjet printer according to the present invention includes a plurality of nozzles for ejecting ink droplets, a plurality of ejection energy generating elements for ejecting ink droplets from each of the plurality of nozzles, and a plurality of ejection energy generating elements. A method of controlling an inkjet printer, which comprises an inkjet head having a plurality of meniscus vibrating elements that vibrate the meniscus of each ink in the nozzle, and drives an ejection energy generating element to eject ink droplets from the nozzle to perform printing. The maximum drive frequency is the drive frequency of the discharge energy generation element when ink droplets are continuously discharged from the nozzle at the shortest cycle, and the nozzles that stop discharging ink droplets at a specified timing during printing are paused. When the meniscus vibrating element that is a nozzle and vibrates the meniscus in the idle nozzle is the first meniscus vibrating element, the first meniscus vibrating element is driven at a first frequency lower than the maximum driving frequency during printing, and the meniscus vibrating element in the idle nozzle is driven. When the first meniscus vibrating element is driven at the first frequency, the first meniscus vibrating element is driven a plurality of times at the resonance frequency of the inkjet head to vibrate the meniscus in the pause nozzle. To do.

According to the present invention, when the first meniscus vibrating element is driven at the first frequency lower than the maximum driving frequency, the first meniscus vibrating element is driven a plurality of times at the resonance frequency of the inkjet head, and the meniscus of the ink in the idle nozzles is driven. Is vibrating. Therefore, in the present invention, when the first meniscus vibrating element is driven at the first frequency, the amplitude of vibration of the meniscus of the ink in the pause nozzle is effectively increased to enhance the effect of stirring the ink in the pause nozzle. It will be possible.

Further, according to the present invention, during printing, the first meniscus vibrating element is driven at the first frequency lower than the maximum driving frequency to vibrate the meniscus of the ink in the pause nozzle. Therefore, the first meniscus vibration is generated at the first frequency. Even when the first meniscus vibrating element is driven a plurality of times when the element is driven, the number of times the first meniscus vibrating element is driven per unit time is the same as when the first meniscus vibrating element is driven once at the maximum driving frequency. , The number of times of driving the first meniscus vibrating element per unit time or less can be achieved.

Therefore, in the present invention, for example, the number of times of driving the first meniscus vibrating element per unit time is set to the number of times of driving of the first meniscus vibrating element per unit time when the first meniscus vibrating element is driven once at the maximum driving frequency. When the number of times of driving is the same, the heat generation amount of ink in the pause nozzle is made equal to the heat generation amount of ink in the pause nozzle when the first meniscus vibrating element is driven once at the maximum drive frequency, and the pause nozzle It is possible to enhance the stirring effect of the ink inside.

Further, in the present invention, for example, the number of times the first meniscus vibrating element is driven per unit time is set to the number of times the first meniscus vibrating element is driven once per unit time at the maximum driving frequency. If the number of vibrations is such that the same stirring effect as that of the ink in the pause nozzle when the first meniscus vibrating element is driven once at the maximum drive frequency is obtained by reducing the number of vibrations, It is possible to reduce the heat generation amount of the ink in the pause nozzle while making the ink agitation effect of the ink in the pause nozzle the same as that of the ink in the pause nozzle when the first meniscus vibrating element is driven once at the maximum drive frequency. It will be possible.

As described above, in the present invention, the calorific value of the ink in the pause nozzle is made equal to the calorific value of the ink in the pause nozzle when the first meniscus vibrating element is driven once at the maximum drive frequency, and It is possible to enhance the stirring effect of the ink in the rest nozzle, or to improve the stirring effect of the ink in the rest nozzle by changing the ink in the rest nozzle when the first meniscus vibrating element is driven once at the maximum drive frequency. It is possible to reduce the heat generation amount of the ink in the pause nozzle while keeping the stirring effect the same. Therefore, in the present invention, it is possible to effectively suppress the increase in the viscosity of the ink in the pause nozzle.

As described above, according to the present invention, in an on-demand type ink jet printer, it is possible to effectively suppress an increase in the viscosity of ink in a nozzle that suspends ink droplet ejection at a predetermined timing during printing. It will be possible.

It is a schematic diagram for explaining a schematic configuration of an inkjet printer according to an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the configuration of the inkjet head shown in FIG. 1. FIG. 3 is a diagram showing an example of a waveform of a voltage applied from the control unit shown in FIG. 2 to a piezo element. FIG. 3 is a diagram for explaining an example of a waveform of a voltage applied to the piezo element shown in FIG. 2. FIG. 4 is a diagram for explaining fluctuations in the amplitude of the meniscus of ink in the nozzle when the piezoelectric element shown in FIG. 2 is driven at the resonance frequency of the inkjet head.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Structure of inkjet printer)
FIG. 1 is a schematic diagram for explaining a schematic configuration of an inkjet printer 1 according to an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the configuration of the inkjet head 3 shown in FIG. FIG. 3 is a diagram showing an example of the waveform of the voltage applied to the piezo element 9 from the control unit 12 shown in FIG.

The inkjet printer 1 (hereinafter, referred to as “printer 1”) of the present embodiment is, for example, a commercial inkjet printer, and ejects ink droplets to print on a print medium 2 such as paper. The printer 1 is an on-demand type inkjet printer, and includes an inkjet head 3 that ejects ink droplets toward a print medium 2, a carriage 4 on which the inkjet head 3 is mounted, and a carriage 4 in the main scanning direction (see FIG. A carriage drive mechanism (not shown) that moves the print medium 1 in the Y direction) and a platen 5 on which the print medium 2 for printing is placed.

The inkjet head 3 is arranged on the upper side of the platen 5, and ejects ink drops downward toward the print medium 2 placed on the platen 5. Further, the printer 1 is arranged on a platen 5 and a guide rail 6 for guiding the carriage 4 in the main scanning direction, a plurality of ink tanks (not shown) for accommodating ink to be supplied to the inkjet head 3. And a medium feeding mechanism (not shown) that feeds the print medium 2 in the sub-scanning direction (X direction in FIG. 1) orthogonal to the vertical direction and the main scanning direction.

The inkjet head 3 is formed with a plurality of nozzles 3a for ejecting ink droplets. The plurality of nozzles 3a are arranged in the sub-scanning direction, and the plurality of nozzles 3a form a nozzle row. In the inkjet head 3, for example, a plurality of nozzle rows are arranged in the main scanning direction. The opening at the lower end of the nozzle 3a is an ink ejection port through which an ink droplet is ejected. Further, the ink jet head 3 is formed with a plurality of ink chambers 3b. Each of the plurality of nozzles 3a is connected to each of the plurality of ink chambers 3b. The upper end of the nozzle 3a is connected to the ink chamber 3b.

The inkjet head 3 includes a plurality of piezo elements (piezoelectric elements) 9 for ejecting ink droplets from the nozzles 3a, and a vibration plate 10 to which the piezo elements 9 are attached. The piezo element 9 is composed of a piezoelectric body and two electrodes sandwiching the piezoelectric body therebetween. Each of the plurality of piezo elements 9 is arranged on each wall surface of each of the plurality of ink chambers 3b, and ejects ink droplets from each of the plurality of nozzles 3a. The piezo element 9 of this embodiment is an ejection energy generation element for ejecting an ink droplet from the nozzle 3a.

The plurality of piezo elements 9 are electrically connected to the control unit 12 of the printer 1. The controller 12 drives the piezo element 9 to eject ink droplets from the nozzle 3a. The waveform of the voltage applied from the controller 12 to the piezo element 9 (voltage waveform) fluctuates as shown in FIG. 3, for example. FIG. 3 shows the waveform of the voltage applied to the piezo element 9 when ink droplets are continuously ejected from the nozzle 3a in the shortest cycle. As shown in FIG. 3, when ink droplets are continuously ejected from the nozzle 3a at the shortest cycle, the drive signal SG for driving the piezo element 9 is input to the piezo element 9 at a constant cycle T1. That is, when the ink droplets are continuously ejected from the nozzle 3a in the shortest cycle, the control unit 12 drives the piezo element 9 at a constant drive frequency.

The drive signal SG of the present embodiment includes the first drive signal SG1 for deforming the piezo element 9 so that the ink droplets are ejected from the nozzle 3a and the vibration of the piezo element 9 after the ink droplets are ejected from the nozzle 3a. And a second drive signal SG2 for driving the signal. The drive time of the piezo element 9 by the second drive signal SG2 is shorter than the drive time of the piezo element 9 by the first drive signal SG1. In the following description, the drive frequency of the piezo element 9 when ink droplets are continuously ejected from the nozzle 3a in the shortest cycle is the maximum drive frequency. The maximum driving frequency corresponds to the number of ink droplets that can be ejected from the nozzle 3a in the printer 1 in one second. That is, the cycle T1 is the minimum time required for the printer 1 to eject the ink droplet from the nozzle 3a twice.

The printer 1 is equipped with a maintenance unit (not shown) for preventing the occurrence of problems such as clogging of the nozzles 3a. The maintenance unit is arranged at a position outside the print area of the print medium 2 in the main scanning direction. The maintenance unit includes, for example, a capping mechanism that covers the lower surface of the inkjet head 3 and sucks ink from the nozzles 3a.

(Control method of inkjet printer)
FIG. 4 is a diagram for explaining an example of the waveform of the voltage applied to the piezo element 9 shown in FIG. FIG. 5 is a diagram for explaining the fluctuation of the amplitude of the meniscus M of the ink in the nozzle 3a when the piezo element 9 shown in FIG. 2 is driven at the resonance frequency of the inkjet head 3.

As described above, since the printer 1 is an on-demand type ink jet printer, the nozzles 3a that do not eject ink drops at a predetermined timing even when printing the print medium 2 do not eject ink drops. Exists. For example, the drive signal SG indicated by the solid line in FIG. 4(A) is input to a certain piezo element 9 from the control unit 12, and the nozzle 3a corresponding to this piezo element 9 responds to the input drive signal SG according to the input drive signal SG. Eject ink drops. Specifically, the drive signal SG is input to a certain piezo element 9 at a time interval that is a natural number multiple of the cycle T1, and the nozzle 3a corresponding to this piezo element 9 has a time interval that is a natural number multiple of the cycle T1. Eject ink drops. The drive signal SG shown by the broken line in FIG. 4A is shown for convenience, and the drive signal SG shown by the broken line is not input from the control unit 12 to the piezo element 9.

It is assumed that the nozzle 3a that suspends ink droplet ejection at a predetermined timing when printing the print medium 2 is a rest nozzle 3a, and the piezo element 9 for ejecting an ink droplet from the rest nozzle 3a is a first piezo element 9. The control unit 12 drives the first piezo element 9 at a first frequency lower than the maximum drive frequency during printing of the print medium 2 so that ink droplets are not ejected from the pause nozzle 3a. The meniscus M (see FIG. 2) of the ink is vibrated (slightly vibrated), and when the first piezo element 9 is driven at the first frequency, the first piezo element 9 is driven a plurality of times at the resonance frequency of the inkjet head 3. Then, the meniscus M of the ink in the resting nozzle 3a is vibrated so that the ink droplets are not ejected from the resting nozzle 3a.

That is, when printing the print medium 2, the control unit 12 sends the drive signal SG5 for driving the first piezo element 9 to the first piezo element 9 at a cycle T2 longer than the cycle T1, as shown in FIG. 4B. The first piezo element 9 is driven so as to vibrate the first piezo element 9 so that the meniscus M of the ink in the resting nozzle 3a oscillates, and the first piezo element 9 is driven when the first piezo element 9 is driven in the cycle T2. The drive signal SG5 to be input is input to the first piezo element 9 a plurality of times at the resonance period Tc of the inkjet head 3, and the first piezo element 9 is vibrated so that the meniscus M of the ink in the pause nozzle 3a vibrates. There is. The resonance cycle Tc is significantly shorter than the cycle T2. The driving time of the piezo element 9 by the driving signal SG5 is shorter than the driving time of the piezo element 9 by the first driving signal SG1.

In the example shown in FIG. 4, the cycle T2 is four times as long as the cycle T1. That is, in the example shown in FIG. 4, the controller 12 drives the first piezo element 9 at the first frequency that is ¼ of the maximum drive frequency when printing the print medium 2. Further, in the example shown in FIG. 4, the control unit 12 drives the first piezo element 9 four times when driving the first piezo element 9 in the cycle T2. That is, the control unit 12 inputs the drive signal SG5 to the first piezo element 9 four times at the resonance cycle Tc when driving the first piezo element 9 at the cycle T2.

When the drive signal SG5 is input to the first piezo element 4 four times with the resonance period Tc, the amplitude AM of the vibration of the ink meniscus M in the pause nozzle 3a fluctuates as shown in FIG. 4B, for example. To do. That is, since the drive signal SG5 is input to the first piezo element 9 at the resonance cycle Tc of the inkjet head 3, the amplitude AM of the meniscus M gradually increases as the number of times the drive signal SG5 is input. Moreover, when the input of the drive signal SG5 is completed four times, the amplitude AM of the meniscus M gradually decreases.

In the example shown in FIG. 4, the cycle T2 is four times as long as the cycle T1, and when the first piezo element 9 is driven in the cycle T2, the first piezo element 9 is driven four times. Therefore, the number of times the first piezo element 9 is driven per unit time is the same as the number of times the first piezo element 9 is driven per unit time when the first piezo element 9 is driven once in the cycle T1. There is. That is, the number of times the first piezo element 9 is driven per unit time is the same as the number of times the first piezo element 9 is driven per unit time when the first piezo element 9 is driven once at the maximum drive frequency. ing.

Further, for example, the control unit 12 drives the first piezo element 9 at a cycle T2 that is five times the cycle T1, and when driving the first piezo element 9 at a cycle T2, the control section 12 drives the first piezo element 9 three times. You may drive. That is, the control unit 12 drives the first piezo element 9 at a first frequency that is ⅕ of the maximum drive frequency, and when driving the first piezo element 9 at the first frequency, outputs the drive signal SG5 as a resonance cycle. It may be input to the first piezo element 9 three times at Tc. In this case, the number of times the first piezo element 9 is driven per unit time is greater than the number of times the first piezo element 9 is driven per unit time when the first piezo element 9 is driven once in the cycle T1. It's getting less.

(Main effects of this embodiment)
As described above, in the present embodiment, when driving the first piezo element 9 in the cycle T2, the control unit 12 drives the first piezo element 9 a plurality of times in the resonance cycle Tc of the inkjet head 3 and pauses. The ink meniscus M in the pause nozzle 3a is vibrated so that ink droplets are not ejected from the nozzle 3a. Therefore, in the present embodiment, when driving the first piezo element 9 in the cycle T2, as shown in FIG. 4B, the amplitude AM of the vibration of the meniscus M of the ink in the pause nozzle 3a is effectively increased. As a result, the effect of stirring the ink in the rest nozzle 3a can be enhanced.

Further, in the present embodiment, when the printing medium 2 is printed, the first piezo element 9 is driven at the cycle T2 longer than the cycle T1 to vibrate the meniscus M of the ink in the pause nozzle 3a. Even if the first piezo element 9 is driven a plurality of times when the first piezo element 9 is driven, the number of times the first piezo element 9 is driven per unit time is the number of times the first piezo element 9 is driven once in the cycle T1. At this time, it is possible to reduce the number of times the first piezo element 9 is driven per unit time.

Therefore, as in the example shown in FIG. 4, the number of times the first piezo element 9 is driven per unit time is the unit time of the first piezo element 9 when the first piezo element 9 is driven once in the cycle T1. If it is equal to the number of times of driving per hit, the heat generation amount of ink in the pause nozzle 3a is the same as the heat generation amount of ink in the pause nozzle 3a when the first piezo element 9 is driven once in the cycle T1. While it is the same as above, it becomes possible to enhance the effect of stirring the ink in the pause nozzle 3a.

In addition, for example, the number of times of driving the first piezo element 9 per unit time is smaller than the number of times of vibration of the first piezo element 9 per unit time when the first piezo element 9 is driven once in the cycle T1. Assuming that the number of vibrations is such that the same stirring effect as that of the ink in the pause nozzle 3a when the first piezoelectric element 9 is driven once in the cycle T1, the ink in the pause nozzle 3a can be obtained. While reducing the heat generation amount of the ink in the resting nozzle 3a while making the stirring effect of the same as the stirring effect of the ink in the resting nozzle 3a when the first piezo element 9 is driven once in the cycle T1. Will be possible.

As described above, in the present embodiment, the heat generation amount of the ink in the pause nozzle 3a is made equal to the heat generation amount of the ink in the pause nozzle 3a when the first piezo element 9 is driven once in the cycle T1. , It becomes possible to enhance the ink stirring effect in the pause nozzle 3a, or the ink stirring effect in the pause nozzle 3a when the first piezo element 9 is driven once in the cycle T1. It is possible to reduce the heat generation amount of the ink in the pause nozzle 3a while maintaining the same effect of stirring the ink in the pause nozzle 3a. Therefore, in this embodiment, it is possible to effectively suppress an increase in the viscosity of the ink in the rest nozzle 3a.

(Other embodiments)
The embodiment described above is an example of the preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

In the above-mentioned form, the cycle T2 may be twice or three times as long as the cycle T1, or may be six times or more. Further, in the above-described embodiment, the number of times of driving the first piezo element 9 when driving the first piezo element 9 in the cycle T2 may be two times, or may be five times or more. Even in these cases, the number of times the first piezo element 9 is driven per unit time is the number of times the first piezo element 9 is driven per unit time when the first piezo element 9 is driven once in the cycle T1. It is less than the number of times. However, the number of times the first piezo element 9 is driven per unit time is slightly larger than the number of times the first piezo element 9 is driven per unit time when the first piezo element 9 is driven once in the cycle T1. Is also good.

In the above-described embodiment, the piezo element 9 for ejecting the ink droplet from the nozzle 3a is used to vibrate the meniscus M of the ink in the pause nozzle 3a so that the ink droplet is not ejected from the pause nozzle 3a. The inkjet head 3 may include a plurality of meniscus vibrating elements that vibrate the meniscus M of each ink in the plurality of nozzles 3 a in addition to the plurality of piezoelectric elements 9. The meniscus vibrating element is, for example, a piezo element. Further, the plurality of meniscus vibrating elements are electrically connected to the control section 12, and the control section 12 drives the meniscus vibrating elements.

In this case, when the meniscus vibrating element that vibrates the meniscus M in the pause nozzle 3a is the first meniscus vibrating element, the control unit 12 causes the first meniscus vibrating element to be lower than the maximum driving frequency when printing the print medium 2. When the first meniscus vibrating element is driven at the first frequency while driving the first meniscus vibrating element at the first frequency by vibrating the meniscus M of the ink in the rest nozzle 3a so that the ink droplets are not ejected from the rest nozzle 3a by driving at the first frequency. The first piezo element 9 is driven a plurality of times at the resonance frequency of the head 3 to vibrate the ink meniscus M in the pause nozzle 3a so that ink droplets are not ejected from the pause nozzle 3a.

Even in this case, similarly to the above-described embodiment, when the first meniscus vibrating element is driven at the first frequency, the amplitude AM of the vibration of the meniscus M of the ink in the pause nozzle 3a is effectively increased. Thus, it is possible to enhance the ink stirring effect of the pause nozzle 3a. Further, similarly to the above-described embodiment, even when the first meniscus vibrating element is driven a plurality of times when driving the first meniscus vibrating element at the first frequency, the number of times the first meniscus vibrating element is driven per unit time is It is possible to set the number of times of driving the first meniscus vibrating element per unit time when the first meniscus vibrating element is driven once at the maximum driving frequency.

Therefore, as in the above-described embodiment, the heat generation amount of ink in the pause nozzle 3a is the same as the heat generation amount of ink in the pause nozzle 3a when the first meniscus vibrating element is driven once at the maximum drive frequency. It is possible to enhance the stirring effect of the ink in the pause nozzle 3a while driving the first meniscus vibrating element once at the maximum driving frequency. It is possible to reduce the heat generation amount of the ink in the pause nozzle 3a while maintaining the same effect of stirring the ink in the pause nozzle 3a at the time. Therefore, even in this case, it is possible to effectively suppress an increase in the viscosity of the ink in the pause nozzle 3a.

In the above-described embodiment, the ejection energy generating element for ejecting the ink droplet from the nozzle 3a is a piezo element, but the ejection energy generating element for ejecting the ink droplet from the nozzle 3a is a heater (heating element). May be. That is, in the above-described embodiment, the printer 1 ejects the ink droplets from the nozzle 3a by the piezo method, but the printer 1 may eject the ink droplets by the thermal method. Further, the above meniscus vibrating element may be a heater (heating element).

In the above-described embodiment, the printer 1 is a serial head type printer in which the carriage 4 on which the inkjet head 3 is mounted moves in the main scanning direction, but the printer 1 may be a line head type printer. That is, the printer 1 may include an ink jet head (line head) having a length equivalent to the width of the print medium 2 instead of the carriage 4 and the inkjet head 3 mounted on the carriage 4. Further, in the above-described embodiment, the printer 1 may be a 3D printer that models a three-dimensional model.

1 Printer (inkjet printer)
3 Inkjet head 3a Nozzle 9 Piezo element (ejection energy generating element)
12 Controller M Meniscus

Claims (4)

In an inkjet printer that ejects ink droplets for printing,
An ink jet head having a plurality of nozzles for ejecting ink droplets and a plurality of ejection energy generating elements for ejecting ink droplets from each of the plurality of nozzles; and an ink droplet is ejected from the nozzles by driving the ejection energy generating element. And a control unit for discharging,
The maximum drive frequency is set as the drive frequency of the discharge energy generation element when ink droplets are continuously discharged at the shortest cycle, and the nozzles that stop discharging ink droplets at a predetermined timing during printing are set. When a resting nozzle is used and the ejection energy generating element for ejecting ink droplets from the resting nozzle is a first ejection energy generating element,
At the time of printing, the control unit drives the first ejection energy generating element at a first frequency lower than the maximum driving frequency to vibrate the meniscus of ink in the pause nozzle, and at the first frequency, An inkjet printer, characterized in that, when driving one ejection energy generating element, the first ejection energy generating element is driven a plurality of times at a resonance frequency of the inkjet head to vibrate the meniscus in the pause nozzle. In an inkjet printer that ejects ink droplets for printing,
A plurality of nozzles for ejecting ink droplets, a plurality of ejection energy generating elements for ejecting ink droplets from each of the plurality of nozzles, and a plurality of meniscus vibrating elements for vibrating the meniscus of each ink in the plurality of nozzles. An inkjet head, and a control unit that drives the ejection energy generating element and the meniscus vibrating element,
The maximum drive frequency is set as the drive frequency of the discharge energy generation element when ink droplets are continuously discharged at the shortest cycle, and the nozzles that stop discharging ink droplets at a predetermined timing during printing are set. A rest nozzle, and the meniscus vibrating element that vibrates the meniscus in the rest nozzle is a first meniscus vibrating element,
At the time of printing, the control unit drives the first meniscus vibrating element at a first frequency lower than the maximum driving frequency to vibrate the meniscus in the pause nozzle, and at the first frequency, the first meniscus vibrating element. An inkjet printer, characterized in that when the vibrating element is driven, the first meniscus vibrating element is driven a plurality of times at the resonance frequency of the inkjet head to vibrate the meniscus in the pause nozzle. An ink jet head having a plurality of nozzles for ejecting ink droplets and a plurality of ejection energy generating elements for ejecting ink droplets from each of the plurality of nozzles, and the ink droplets are ejected from the nozzles by driving the ejection energy generating element. A method for controlling an inkjet printer that discharges and prints
The maximum drive frequency is set as the drive frequency of the discharge energy generation element when ink droplets are continuously discharged at the shortest cycle, and the nozzles that stop discharging ink droplets at a predetermined timing during printing are set. When a resting nozzle is used and the ejection energy generating element for ejecting ink droplets from the resting nozzle is a first ejection energy generating element,
During printing, the first ejection energy generating element is driven at a first frequency lower than the maximum driving frequency to vibrate the meniscus of ink in the pause nozzle, and the first ejection energy generating element is driven at the first frequency. The method for controlling an inkjet printer, wherein the first ejection energy generating element is driven a plurality of times at a resonance frequency of the inkjet head to vibrate the meniscus in the pause nozzle. A plurality of nozzles for ejecting ink droplets, a plurality of ejection energy generating elements for ejecting ink droplets from each of the plurality of nozzles, and a plurality of meniscus vibrating elements for vibrating the meniscus of each ink in the plurality of nozzles. A method of controlling an inkjet printer, comprising an inkjet head, wherein the ejection energy generating element is driven to eject ink droplets from the nozzle to perform printing,
The maximum drive frequency is set as the drive frequency of the discharge energy generation element when ink droplets are continuously discharged at the shortest cycle, and the nozzles that stop discharging ink droplets at a predetermined timing during printing are set. A rest nozzle, and the meniscus vibrating element that vibrates the meniscus in the rest nozzle is a first meniscus vibrating element,
During printing, the first meniscus vibrating element is driven at a first frequency lower than the maximum driving frequency to vibrate the meniscus in the pause nozzle, and at the same time, the first meniscus vibrating element is driven. At this time, the method for controlling an inkjet printer is characterized in that the first meniscus vibrating element is driven a plurality of times at the resonance frequency of the inkjet head to vibrate the meniscus in the pause nozzle.

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