JP7151412B2 - Liquid ejector - Google Patents

Description

The present invention relates to a liquid ejection device.

2. Description of the Related Art A liquid ejection apparatus is known that controls the operation of a liquid ejection unit having a liquid ejection head to eject liquid onto an ejection target at appropriate timing and amount. 2. Description of the Related Art As an example of such a liquid ejecting apparatus, an inkjet printer is known which ejects liquid ink onto a recording medium to form characters and images.

The liquid ejection unit, for example, includes at least a liquid ejection head using a piezoelectric element (piezo actuator) and a drive waveform generation circuit that generates and outputs a drive voltage waveform applied to operate the piezoelectric element. A piezoelectric element is an element that expands and contracts according to the applied driving voltage waveform. The liquid ejection unit applies a predetermined driving voltage waveform to the piezoelectric element to change the volume of the liquid chamber communicating with the nozzle opening provided in the liquid ejection head. This change in volume causes the pressure in the liquid chamber to fluctuate, and the energy of this fluctuation causes the liquid to be ejected from the nozzle port in the form of droplets.

The magnitude and timing of the driving voltage waveform applied to the piezoelectric element affect the characteristics of the ejected droplets. Ejection does not occur, and the formed image becomes an abnormal image. Therefore, it is required to maintain and improve the quality of the droplet ejection state by observing the drive voltage waveform applied to the piezoelectric element in the liquid ejection head and detecting an abnormality in the drive voltage waveform.

As a technique for detecting an abnormality in a drive voltage waveform, there is known a technique for detecting an abnormality in the drive voltage waveform based on the comparison result by comparing a voltage pulse signal of the drive voltage waveform with a predetermined reference voltage. (See Patent Document 1).

Conventional technology counts voltage pulses by comparison with a reference voltage, and detects abnormalities in the voltage to be observed based on the result of this counting. A drive waveform generation circuit that generates a drive voltage waveform may have "dull", "overshoot" or "undershoot" in the drive voltage waveform due to the effects of temperature characteristics and aged deterioration. With technology, it is difficult to distinguish between a drive voltage waveform that accompanies such an anomaly and a normal drive voltage waveform. Therefore, in the conventional technology, there is a problem in improving the detection accuracy of abnormality in the drive voltage waveform.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid ejecting apparatus capable of detecting abnormalities including waveform deformation such as dullness and waveform distortion of a drive voltage waveform.

In order to solve the above-described problems, one aspect of the present invention provides a recording head including a plurality of piezoelectric elements for ejecting liquid as droplets from a nozzle orifice in response to application of a drive voltage waveform; A plurality of drive voltage waveform generators that simultaneously generate drive voltage waveforms based on the same drive waveform data, and a drive voltage waveform comparison that compares the same drive voltage waveforms generated by different drive voltage waveform generators. and a control unit that determines whether or not there is an abnormality in the drive voltage waveform based on the comparison result of the drive voltage waveform comparison unit.

According to the present invention, it is possible to detect abnormalities including waveform deformation such as dullness and waveform distortion of the drive voltage waveform.

1 is a schematic diagram showing the configuration of a printer that is an embodiment of a liquid ejecting apparatus according to the present invention; FIG. FIG. 2 is a side view showing the configuration of an embodiment of a liquid ejection head included in the printer; FIG. 2 is a bottom view showing an example of the structure of the liquid ejection head; FIG. 2 is a plan view showing an example of a nozzle port in the recording head; 1 is an exploded perspective view showing the configuration of an embodiment of a liquid ejection head provided in the printer; FIG. FIG. 3 is a functional block diagram of the liquid ejection unit; FIG. 4 is a diagram showing an example of waveforms of driving signals applied to piezoelectric elements of the recording head; FIG. 5 is a diagram showing a comparative example of waveforms of drive signals applied to the piezoelectric element; 4 is a flowchart showing an example of drive voltage waveform comparison processing executed in the liquid ejection device; 4 is a flowchart showing another example of the drive voltage waveform comparison process;

[Overview of the present invention]
A liquid ejecting apparatus according to the present invention includes a plurality of different drive waveform generation units, a drive voltage comparison unit that compares the drive voltage waveforms generated by the drive voltage waveform generation units, and an abnormality in the drive voltage waveform based on the comparison result. and a controller for judging, and judging abnormality of the drive voltage waveform based on the comparison result of each drive voltage waveform.

A conventionally known liquid ejecting apparatus has a plurality of ejection openings (nozzle openings) for ejecting liquid, and each nozzle is provided with a piezoelectric element for generating energy for ejecting liquid. A drive voltage waveform generator generates a drive voltage waveform for driving the piezoelectric element. The drive voltage waveform generator can generate a plurality of drive voltage waveforms with different magnitudes and pulse periods of the generated drive voltage. For example, in order to control the size of the ejected droplets (large, medium, or small), it is possible to generate a dedicated drive voltage waveform, or to generate a drive voltage waveform consisting of minute vibrations for adjustment. , are sequentially connected and applied to the piezoelectric element. As described above, when a plurality of different drive voltage waveforms are generated and sequentially connected and applied to the piezoelectric element, the cycle of the drive voltage waveform becomes longer, which is not suitable for speeding up the ejection operation.

A liquid ejecting apparatus according to the present invention includes a plurality of drive voltage waveform generators for piezoelectric elements, and one of the drive voltage waveform generators generates a drive voltage waveform for controlling the size of a droplet. , the other drive voltage waveform generator can generate a micro-vibration waveform. Further, the drive voltage waveform and the connection between the piezoelectric elements can be switched by the switching unit and applied to the piezoelectric elements as appropriate. With these configurations, the liquid ejecting apparatus according to the present invention detects an abnormality in the drive voltage waveform generator instead of comparing the drive voltage waveform generated by the drive voltage waveform generator with the reference voltage. can also determine the content of

In particular, in the liquid ejecting apparatus according to the present invention, each drive voltage waveform has "blur", "overshoot", and "undershoot" caused by temperature characteristics and aged deterioration, which cannot be detected by comparison with a reference voltage. ” can also be detected and judged.

Further, in the liquid ejection apparatus according to the present invention, the generated drive voltage waveforms are compared in a state where the connection between the drive waveform generator and the piezoelectric element is cut off by the switching unit, thereby narrowing down the location where the abnormality occurs. An embodiment of a liquid ejecting apparatus according to the present invention will be described below with reference to the drawings.

[Overall Configuration of Inkjet Printer 1000]
FIG. 1 is an overall configuration diagram of an inkjet printer 1000, which is an embodiment of a liquid ejecting apparatus according to the present invention. The inkjet printer 1000 exemplifies an on-demand line scanning type.

As shown in FIG. 1, the inkjet printer 1000 includes an image forming section 210, a paper feeding section 220, a registration adjusting section 230, a drying section 240, a recording medium reversing section 250, and a paper discharging section 290. ing. An example of the flow of an image forming output operation (printing operation) in the inkjet printer 1000 will be described.

First, the recording medium W<b>1 stacked on the paper feed stack 221 of the paper feed section 220 is picked up one by one by the air separation section 222 and conveyed toward the image forming section 210 . When the recording medium W1 transported from the paper feeding section 220 reaches the registration adjustment section 230, the inclination of the recording medium W1 is corrected by a pair of registration rollers 231 provided inside the registration adjustment section 230. FIG.

The registration-adjusted recording medium W1 is sent to an image forming section 210, and the front end of the recording medium is held by a recording medium gripper 11 provided on the surface of a cylindrical drum 10. As the drum 10 rotates, head arrays 28K- 28P is transported to a position opposite to 28P. In the image forming unit 210, head arrays 28K to 28P, which are recording head units that eject ink by an inkjet method, are arranged radially at an angle along the surface of the cylindrical drum 10 while being filled with predetermined ink colors. ing.

A plurality of head arrays 28K to 28P form an image on the recording medium W1 by ejecting ink (liquid) onto the outer peripheral surface of the recording medium W1 held on the surface of the drum 10 from the outside of the circumference. A blank ejection receiver 12 is provided on the outer peripheral surface of the drum 10, and receives blank ejection ink when the head module 28 is not ejecting ink onto the recording medium W1. After the image is formed, the recording medium W1 is sent to the drying section 240 .

A drying unit 241 is attached to the drying unit 240, and the water content of the recording medium W1 is evaporated by passing the recording medium W1 thereunder. Further, the drying section 240 is provided with a recording medium reversing section 250 including a recording medium reversing mechanism 251 . During double-sided printing, the recording medium W<b>1 is reversed by the recording medium reversing unit 250 and conveyed to the image forming unit 210 again by the reversing conveying unit 252 . Before reaching the drum 10, the inclination of the recording medium W1 is corrected by a registration roller 253 provided inside the image forming section 210. FIG. The recording medium W1 that has been dried by the drying section 240 is conveyed to the paper discharging section 290 and stacked with the edges of the recording medium W1 aligned.

[Embodiment of Liquid Ejection Head Unit]
Next, an embodiment of a liquid ejection head unit that can be applied to the liquid ejection apparatus according to the present invention will be described. An embodiment of the liquid ejection head unit is the head module 28 already described. FIG. 2 is a side view of the head module 28. FIG.

As shown in FIG. 2, the head module 28 mainly includes the recording head 15, the cable 16, and the drive control board 17. As shown in FIG.

The drive control board 17 has a drive control section 26 , a drive voltage waveform generation section 271 and a storage section 18 mounted thereon.

A drive control board connector 19 and a head side connector 20 are attached to both ends of the cable 16, and analog signal communication and digital signal communication between the head board 22 mounted on the recording head 15 and the drive control board 17 are performed. responsible for

The recording head 15 mainly includes a residual vibration detection module 21, a head substrate 22, a head driving IC substrate 24 having a switching section for switching which piezoelectric element 42 the driving voltage waveform is applied to, and an in-head ink tank 23. , and a rigid plate 25 . If the configuration of the liquid ejection head provided in the inkjet printer 1000 is of the line scanning type, the line head configuration is such that the recording heads 15 are arranged in the width direction of the recording medium W1, which is the direction perpendicular to the conveying direction of the recording medium W1. be. However, the present invention is a serial scanning type in which an image is formed by moving one or a plurality of recording heads 15 in the width direction of the recording medium W1 and further conveying the recording medium W1 in the conveying direction. It can also be applied to a discharge device.

[Configuration of recording head 15]
FIG. 3 is a schematic diagram showing an example in which the recording heads 15 are arranged in a line head configuration. The head module 28 according to the present embodiment includes a black head array 28K that ejects black ink droplets, a cyan head array 28C that ejects cyan ink droplets, and a magenta head that ejects magenta ink droplets. It is a collection of components distinguished for each color of liquid ink to be ejected, such as an array 28M and a yellow head array 28Y for ejecting yellow ink droplets. Each head array is arranged in a direction perpendicular to the conveying direction (arrow direction) of the recording medium. By arraying the heads in this way, a wide printing area is ensured.

4 is a bottom view of each body of the recording head 15. FIG. The bottom surface of the recording head 15 forms a nozzle surface 29 on which a plurality of printing nozzles 30 are arranged in a zigzag pattern. Liquid droplets are ejected from each printing nozzle 30 arranged in the printing nozzles 30 based on expansion and contraction of the piezoelectric element 42 . By arranging the print nozzles 30 in a zigzag arrangement, it is possible to increase the resolution of the image formed by the ejected liquid.

[Detailed Configuration of Recording Head 15]
Next, a detailed configuration of the recording head 15 will be described with reference to FIG. The recording head 15 is mainly composed of a nozzle plate 31, a pressure chamber plate 33, a restrictor plate 35, a diaphragm plate 38, a rigid plate 25, and a group of piezoelectric elements 46, which are piezoelectric elements. .

A nozzle plate 31 in which a large number of print nozzles 30 are arranged in a zigzag pattern, a pressure chamber plate 33 in which individual pressure chambers 32 corresponding to the print nozzles 30 are formed, a common ink flow path 39, and an individual A restrictor plate 35 formed with a restrictor 34 communicating with the pressure chambers 32 to control the flow rate of ink to the individual pressure chambers 32, a vibration plate 36, and a diaphragm plate 38 provided with a filter 37 are sequentially stacked and positioned. A flow path plate is constructed by joining them together. The channel plate is joined to the rigid plate 25 so that the filter 37 faces the opening of the common ink channel 39 .

The upper open end of the ink introduction pipe 41 is connected to the common ink flow path 39 of the rigid plate 25, and the lower open end of the ink introduction pipe 41 is connected to an in-head ink tank filled with ink.

A piezoelectric element driving IC 44 is mounted on the piezoelectric element support substrate 43, and a piezoelectric element group 46 configured by arranging a large number of piezoelectric elements 42 is inserted through an opening 40 provided in the rigid plate 25, and each The recording head 15 is constructed by bonding and fixing the free end of the piezoelectric element 42 to the diaphragm 36 . In FIG. 5, the print nozzles 30, the individual pressure chambers 32, the restrictors 34, and other factors are reduced for simplification.

[Functional Configuration of Head Module 28]
Next, the functional configuration of the head module 28 will be explained using FIG. The head module 28 is composed of the recording head control section 53 and the recording head 15 .

The recording head control section 53 includes a head control section 50 , a head drive section 27 and a drive voltage waveform comparison section 51 .

The recording head 15 includes a driving voltage waveform switching section 52 and a plurality of piezoelectric elements 42 .

The head control unit 50 controls the head driving unit 27 based on the storage unit 18 that stores drive waveform data and the information in the storage unit 18, and determines whether there is an abnormality based on the result of the drive voltage waveform comparison unit 51. It has a control unit 48 for The drive voltage waveform comparison unit 51 can compare two or more drive voltage waveforms. It consists of a comparator that compares The drive voltage waveform comparison unit 51 may receive a plurality of drive voltage waveforms at the same time and compare them at the same time. , may be provided with a configuration for sequentially switching inputs. When a comparator is used for the drive voltage waveform comparison unit 51, it is sufficient if the output is asserted when the difference between the drive waveform voltages to be compared is equal to or greater than a certain value. In this case, the control unit 48 determines that there is an abnormality when there is an output from the comparator.

The recording head control section 53 includes a plurality of drive waveform generation sections (a first drive voltage waveform generation section 271A and a second drive voltage waveform generation section 271B) in the head drive section 27 for the purpose of improving the drive frequency. The first drive voltage waveform generator 271A and the second drive voltage waveform generator 271B have the same configuration and functions. Therefore, the first drive voltage waveform generator 271A and the second drive voltage waveform generator 271B can generate the same drive voltage waveform. The operations of the first drive voltage waveform generation section 271A and the second drive voltage waveform generation section 271B are controlled by the control section 48 .

The drive voltage waveform switching section 52 provided in the recording head 15 operates as a switch for switching the piezoelectric element 42 that applies the drive voltage waveform generated by the head drive section 27 . The drive voltage waveform switching unit 52 controls which piezoelectric element 42 to apply the drive voltage waveforms generated by the first drive voltage waveform generation unit 271A and the second drive voltage waveform generation unit 271B, and the connection state thereof. . The driving voltage waveform switching section 52 also operates to cut off the connection between the head driving section 27 and the piezoelectric element 42 . In that case, the drive voltage waveforms output from the first drive voltage waveform generation section 271A and the second drive voltage waveform generation section 271B are input to the drive voltage waveform comparison section 51 as they are.

According to the head module 28 having the above configuration, in different drive waveform generators (the first drive voltage waveform generator 271A or the second drive voltage waveform generator 271B), the same drive voltage waveform is generated by the control of the controller 48. can be generated and each applied to one of the piezoelectric elements 42 . At this time, the drive voltage waveforms applied to the piezoelectric element 42 are compared in the drive voltage waveform comparator 51 . This comparison can be done at the same time the drive voltage waveform is applied to the piezoelectric element. For example, the first drive voltage waveform generator 271A and the second drive voltage waveform generator 271A and the second drive voltage waveform generator 271A and the second drive voltage waveform generator 271A and the second drive voltage waveform generator 271A at a timing unrelated to image formation, such as when executing "flushing" that causes a discharge operation to prevent clogging of the print nozzles 30. 271B to generate the same drive voltage waveform and apply it to the piezoelectric element 42 . By comparing the drive voltage waveforms at this time in the drive voltage waveform comparison unit 51, it is possible to determine the occurrence of abnormality in the drive voltage waveform and the type of abnormality.

The drive voltage waveform switching unit 52 does not need to be configured as one module, and may be configured to switch the application of the drive voltage waveform to the piezoelectric element 42 by a plurality of modules.

[Operation of head module 28]
Next, the abnormality detection operation in the head module 28 according to this embodiment will be described with reference to FIG. FIG. 7 illustrates a method of detecting an abnormality in the recording head 15 and the drive voltage waveform generator 271 by comparing drive voltage waveforms.

Note that the liquid ejection apparatus according to the present invention can compare drive voltage waveforms in real time and detect an abnormality in the drive voltage waveform. Assume that the same drive voltage waveforms at the same time (time X) are compared as shown in FIG.

A waveform A in FIG. 7 is an example of a drive voltage waveform generated in the first drive voltage waveform generator 271A and applied to the piezoelectric element 42a. Waveform B is an example of the drive voltage waveform generated in the second drive voltage waveform generator 271B and applied to the piezoelectric element 42b. Assume that the control unit 48 controls the waveform A and the waveform B so as to have the same drive voltage waveform. In this example, it can be determined that waveform B is delayed with respect to waveform A by focusing on time X in FIG. In this way, the drive waveforms generated by a plurality of different drive waveform generators (the first drive voltage waveform generator 271A and the second drive voltage waveform generator 271B) show that there is a difference in what should be the same. can be detected by comparing Also, by comparing the waveforms A and B in FIG. 7, it can be determined that there is a phase abnormality. In this way, it can be determined that there is an abnormality in the drive voltage waveform to be compared for some reason. By setting a predetermined threshold value for the difference in abnormality, it can be determined that an abnormality has occurred when the difference is equal to or greater than a certain threshold.

If the drive voltage waveform generated by the second drive voltage waveform generation unit 271B and applied to the piezoelectric element 42b is the waveform C, the waveform C is "dull" in comparison with the waveform A. Become. In this case, it can be determined that the voltage value level is abnormal although there is no phase shift.

In the conventional technology, the state of the drive voltage waveform is detected by comparing the drive voltage waveform with the threshold, using the reference voltage as the threshold. It is difficult to detect anomalies related to temporal elements, such as the occurrence of "sounds". If an abnormality related to time elements is to be detected in the prior art, it is necessary to provide a plurality of thresholds corresponding to the time elements and to set reference voltages corresponding to the thresholds of the time elements.

It is conceivable that an abnormality in the drive voltage waveform occurs due to individual differences in the temperature characteristics of the first drive voltage waveform generation section 271A and the second drive voltage waveform generation section 271B. In this regard, according to the head module 28 according to the present embodiment, if at least one threshold value (a reference time for comparison determination) related to the time element is set, an abnormality in the drive voltage waveform can be detected.

Also, a method for distinguishing the type of abnormality in the operation of the head module 28 according to this embodiment will be described. As in the case described with reference to FIG. 7, the waveform C shown in FIG. 8 is an example of the drive voltage waveform generated by the first drive voltage waveform generator 271A and applied to the piezoelectric element 42a. A waveform D is an example of a drive voltage waveform generated in the second drive voltage waveform generator 271B and applied to the piezoelectric element 42b. Assume that the control unit 48 controls the waveform C and the waveform D so as to have the same drive voltage waveform.

In this example, waveform C and waveform D should be the same waveform. However, waveform D does not have the same voltage value level as waveform C at the same time. That is, the second drive voltage waveform generator 271B cannot generate the drive voltage waveform at a sufficient level for the first drive voltage waveform generator 271A.

If this is compared in the drive voltage waveform comparison unit 51 by the number of times the voltage value level exceeds the threshold value within a predetermined time, as is clear from the comparison between judgment C and judgment D, waveform D is compared to waveform C. threshold crossings are reduced. Based on this result, it can be determined that the second drive voltage waveform generator 271B that generated the waveform D has an abnormality in the voltage level.

In FIG. 8, the waveform E is also an example of the drive voltage waveform generated by the second drive voltage waveform generator 271B and applied to the piezoelectric element 42b. Of course, it is assumed that the control unit 48 controls the waveform C and the waveform E so as to have the same drive voltage waveform.

Again, waveform C and waveform E should be the same waveform. However, waveform E does not have the same voltage level as waveform C at the same time, and is delayed. In this case, when comparing the number of times the voltage level exceeds the threshold within a predetermined period of time in the drive voltage waveform comparison unit 51, the number of times the threshold is exceeded is the same, as is clear from the comparison between determination C and determination E. , the timing at which exceeding the threshold value is detected is different. Based on this result, it can be determined that the second driving voltage waveform generating section 271B that generated the waveform E does not have an abnormality in the voltage level, but has an abnormality of delay in generating the driving voltage waveform.

As described above, according to the head module 28, it is possible to detect abnormality in the drive voltage waveform and determine the type of abnormality based on the plurality of drive voltage waveform generators.

[First example of operation flow in head module 28]
Next, an example of the operation flow in the head module 28 according to this embodiment will be described using the flowchart of FIG.

First, the control section 48 instructs the first drive voltage waveform generation section 271A and the second drive voltage waveform generation section 271B to generate and output the same drive voltage waveform. As a result, the same drive voltage waveform generated by the first drive voltage waveform generator 271A and the second drive voltage waveform generator 271B is applied to the piezoelectric element 42 (S901). At this time, it is assumed that the drive voltage waveform switching unit 52 is in a connected state in which the drive voltage waveform generated by the first drive voltage waveform generation unit 271A is applied to the piezoelectric element 42a. It is also assumed that the connection state is set in which the drive voltage waveform generated by the second drive voltage waveform generation section 271B is applied to the piezoelectric element 42b.

The first drive voltage waveform generated by the first drive voltage waveform generator 271A is applied to the piezoelectric element 42a and input to the drive voltage waveform comparator 51 . At the same time, the second drive voltage waveform generated by the second drive voltage waveform generation section 271B is applied to the piezoelectric element 42b and input to the drive voltage waveform comparison section 51 . The drive voltage waveform comparator 51 compares the drive voltage waveforms and outputs the comparison result to the controller 48 (S902).

Subsequently, the control unit 48 determines the comparison result. As illustrated in FIGS. 7 and 8, by comparing the same drive voltage waveforms generated in different drive voltage waveform generators, it is possible to determine whether the difference in voltage value level exceeds a predetermined reference level or whether the phase abnormality ( delay, etc.) exceeds a predetermined reference level. If it exceeds the reference level, it is determined that there is an abnormality (S903/Yes), and notification is sent to the abnormality notification means provided in the inkjet printer 1000 (S904). If it does not exceed the reference level, it is determined that there is no abnormality (S903/No), and the process ends.

[Second Example of Operation Flow in Head Module 28]
Next, another example of the operation flow in the head module 28 according to this embodiment will be described using the flowchart of FIG.

First, the control section 48 instructs the first drive voltage waveform generation section 271A and the second drive voltage waveform generation section 271B to generate and output the same drive voltage waveform. As a result, the same drive voltage waveform generated by the first drive voltage waveform generator 271A and the second drive voltage waveform generator 271B is applied to the piezoelectric element 42 (S1001). At this time, it is assumed that the drive voltage waveform switching unit 52 is in a connected state in which the drive voltage waveform generated by the first drive voltage waveform generation unit 271A is applied to the piezoelectric element 42a. It is also assumed that the connection state is set in which the drive voltage waveform generated by the second drive voltage waveform generation section 271B is applied to the piezoelectric element 42b.

Next, the first drive voltage waveform generated by the first drive voltage waveform generation section 271A is applied to the piezoelectric element 42a and input to the drive voltage waveform comparison section 51 as well. At the same time, the second drive voltage waveform generated by the second drive voltage waveform generation section 271B is applied to the piezoelectric element 42b and input to the drive voltage waveform comparison section 51 . The drive voltage waveform comparison section 51 compares the respective drive voltage waveforms and outputs the comparison result to the control section 48 (S1002).

Subsequently, the control unit 48 determines the comparison result. As illustrated in FIGS. 7 and 8, by comparing the same drive voltage waveforms generated in different drive voltage waveform generators, it is possible to determine whether the difference in voltage value level exceeds a predetermined reference level or whether the phase abnormality ( delay, etc.) exceeds a predetermined reference level. If it exceeds the reference level, it is determined that there is an abnormality (S1003/Yes). If it does not exceed the reference level, it is determined that there is no abnormality (S1003/No), and the process ends.

When it is determined that there is an abnormality in S1003, the drive voltage waveform switching unit 52 includes the drive voltage waveform generation unit (the first drive voltage waveform generation unit 271A and the second drive voltage waveform generation unit 271B), the piezoelectric element ( (S1004).

Subsequently, the control unit 48 again instructs the first drive voltage waveform generation unit 271A and the second drive voltage waveform generation unit 271B to generate the first drive voltage waveform and the second drive voltage waveform. . As a result, the same drive voltage waveforms generated by the first drive voltage waveform generation section 271A and the second drive voltage waveform generation section 271B are input to the drive voltage waveform comparison section 51 (S1005).

Subsequently, the control unit 48 determines the comparison result. As illustrated in FIGS. 7 and 8, the same drive voltage waveforms generated in different drive voltage waveform generators are compared (S1006). The control unit 48 is notified of the comparison result.

Subsequently, it is determined whether the difference in voltage value level exceeds a predetermined reference level, and whether the phase abnormality (delay, etc.) exceeds a predetermined reference level. If it exceeds the reference level, it is determined that there is an abnormality (S1007/Yes). In this case, the cause of the abnormality is considered to be on the side of the drive voltage waveform generation section, so this is reported as the first abnormality (S1008), and the process is terminated.

If it is determined that there is no abnormality in S1007 (S1007/No), the cause of the abnormality is considered to be on the piezoelectric element side, so this fact is notified as a second abnormality (S1009), and the process ends. .

17: drive control board 18: storage unit 19: drive control board connector 20: head side connector 21: residual vibration detection module 22: head board 23: ink tank in head 24: head drive IC board 27: head drive section 28: head Module 42 : Piezoelectric element 48 : Control section 50 : Head control section 51 : Driving voltage waveform comparing section 52 : Driving voltage waveform switching section 53 : Recording head control section 100 : Recording head control section 1000 : Inkjet printer

JP 2012-194663 A

Claims (6)

a recording head comprising a plurality of piezoelectric elements for ejecting liquid droplets from nozzle ports in response to application of a drive voltage waveform;
a plurality of drive voltage waveform generators for simultaneously generating the drive voltage waveforms to be applied to the respective piezoelectric elements based on the same drive waveform data ;
a drive voltage waveform comparison unit that compares the same drive voltage waveforms generated by the different drive voltage waveform generation units;
a control unit that determines whether or not there is an abnormality in the drive voltage waveform based on the comparison result of the drive voltage waveform comparison unit;
A liquid ejection device comprising: a switching unit for switching connection states between the plurality of drive voltage waveform generation units and the plurality of piezoelectric elements;
The switching unit switches to apply each of the drive voltage waveforms generated by the plurality of drive voltage waveform generation units to each of the plurality of piezoelectric elements, and causes the drive voltage waveform comparison unit to apply each of the drive voltage waveforms to each of the piezoelectric elements. Each applied drive voltage waveform is input,
The drive voltage waveform comparison unit compares the same drive voltage waveforms generated by different drive voltage waveform generation units.
The liquid ejection device according to claim 1. 3. The liquid ejection apparatus according to claim 2 , wherein said control section determines whether or not said drive voltage waveform generation section or said recording head is abnormal based on a difference between said same drive voltage waveforms. 4. The liquid ejecting apparatus according to claim 3 , wherein said drive voltage waveform comparison section comprises a comparator that asserts an output as a comparison result when a difference between drive voltage waveforms to be compared is equal to or greater than a predetermined value. The drive voltage waveform comparison unit has an analog-digital conversion unit that converts the drive voltage waveform into a digital signal,
5. The liquid ejecting apparatus according to any one of claims 1 to 4 , wherein comparison is performed using each digitally converted drive voltage waveform. 6. The controller according to any one of claims 1 to 5 , wherein, based on the result of the comparison, the abnormality in the drive voltage waveform is determined by distinguishing whether it is an abnormality in voltage value level or an abnormality in the phase of the waveform. 1. The liquid ejection device according to item 1.

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