JP2016196092A - Liquid droplet discharge device, and abnormality inspection method of the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid droplet discharge device which includes a plurality of nozzles for discharging a liquid droplet when an actuator is driven by a drive signal and a diaphragm displaces, and inspects discharge abnormality of the nozzles in parallel with discharge of droplets from the nozzles.SOLUTION: A liquid droplet discharge device includes: a discharge head 10 which has a plurality of nozzles 11 for discharging a liquid droplet when an actuator 112 is driven by a drive signal and a diaphragm displaces; a drive signal generation part 24 for generating the drive signal; an inspection signal generation part 23 for generating an inspection signal; an abnormality inspection part 25 for inspecting discharge abnormality of the nozzle on the basis of residual oscillation of the diaphragm generated when the actuator is driven by the inspection signal; and a switching part (a head IC 12) which selectively switches between input of the drive signal to the actuator and input of the inspection signal to the actuator.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for inspecting nozzle discharge abnormality in a droplet discharge apparatus having a plurality of nozzles, in which an actuator is driven by a drive signal to displace a diaphragm to discharge liquid droplets. .

As a droplet discharge device, a printer that discharges a liquid droplet, for example, an ink droplet, from a nozzle by driving a drive signal from a drive signal generation circuit to a piezoelectric element (piezo element) is known. Further, in such a printer, there has been proposed a printer that detects residual vibration after driving a piezoelectric element and performs a nozzle discharge inspection based on the residual vibration (see, for example, Patent Document 1). ).

JP 2011-240560 A

By the way, when the nozzle inspection described above and a normal print job are performed separately, the following problems occur. That is, a normal print job cannot be executed unless inspection is completed for all nozzles. Even if a nozzle abnormality occurs during execution of a print job, abnormal ink droplets continue to be ejected until the print job is completed. Thus, a so-called real-time nozzle inspection has been proposed in which a nozzle abnormality inspection is performed while executing a print job. More specifically, not only ink ejection is performed by supplying a drive signal including an ink ejection waveform to the piezoelectric element, but also the nozzle inspection waveform is included in the drive signal to inspect abnormal ejection of the nozzle before and after ink ejection. It has been proposed to do.

However, in this proposed technique, both the ink ejection waveform and the nozzle inspection waveform are generated by the drive signal generation circuit, and therefore the ink ejection waveform and the nozzle inspection waveform are included in the drive signal in this order (or the reverse order). There is a need. As a result, the time required to eject one dot of ink is always the sum of the “time of the ink ejection waveform” and the “time of the nozzle inspection waveform”, and there is room for improvement in reducing the time of the real-time nozzle inspection.

The present invention has been made in view of the above problems, and in a droplet discharge device having a plurality of nozzles, in which a diaphragm is displaced by ejecting an actuator by a drive signal to discharge a liquid droplet, the nozzle It is an object of the present invention to provide a technique capable of inspecting nozzle discharge abnormality in a short time in parallel with the discharge of liquid droplets from the nozzle.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.

One embodiment of the present invention is a droplet discharge device, in which an actuator is driven by a drive signal to displace a vibration plate to discharge a liquid droplet, a discharge head having a plurality of nozzles, and a drive signal A drive signal generation unit that generates an inspection signal, an inspection signal generation unit that generates an inspection signal, and an abnormality inspection unit that inspects nozzle ejection abnormalities based on residual vibration of the diaphragm that is generated when the actuator is driven by the inspection signal And a switching unit that selectively switches between input of a drive signal to the actuator and input of an inspection signal to the actuator.

In this droplet discharge device, in addition to a drive signal generation unit that generates a drive signal for discharging a droplet from a nozzle, an inspection signal generation unit that generates an inspection signal for inspecting nozzle discharge abnormality is provided. Yes. And either a drive signal or a test | inspection signal can be input with respect to an actuator. For this reason, nozzle discharge abnormality can be inspected without being restricted by the droplet discharge timing by the drive signal, and the time for real-time nozzle inspection can be shortened.

Here, in parallel with the ejection of droplets from one of the plurality of nozzles, the inspection signal generation unit gives an inspection signal to the actuator of the other nozzle, and the abnormality inspection unit You may comprise so that discharge abnormality may be determined. In the case of performing so-called real-time nozzle inspection, in which ejection abnormalities of each nozzle are inspected while ejecting liquid droplets from the ejection head, printing signals are input in the conventional technology and inspection signals are input for inspection. Must be performed sequentially, and as a result, the printing time becomes longer. On the other hand, when configured as described above, since the discharge of droplets from one nozzle and the discharge abnormality determination of other nozzles are performed in parallel, even if printing with real-time nozzle inspection is performed, Printing can be performed in the same time as conventional printing without real-time nozzle inspection.

The switching unit is connected in series to the inspection signal generation unit and the actuator, and has a switch that switches between application and non-application of the inspection signal to the actuator, and the abnormality inspection unit inspects the actuator via the switch. A residual vibration inspection unit that inspects residual vibration by measuring a voltage generated between both ends of a resistance existing between the inspection signal generation unit and the actuator when a signal is applied, and a residual inspected by the residual vibration inspection unit A determination unit that determines whether or not a nozzle discharge abnormality has occurred based on vibration may be included. By adopting such a configuration, it is possible to accurately determine the residual vibration, and it is possible to easily detect nozzle ejection abnormalities.

Further, the switch may be a transistor and the resistor may be an on-resistance of the transistor, and the device can be configured with a small number of parts.

In addition, the switching unit has a switch control unit that controls opening and closing of a plurality of switches, and the switch control unit closes one switch of the plurality of switches and opens another switch to be connected to the one switch. Alternatively, the inspection signal may be input only to the terminal.
As a result, it is possible to detect a discharge abnormality for each nozzle and perform an accurate inspection.

Further, according to another aspect of the present invention, an abnormal discharge of a nozzle is inspected in a droplet discharge device having a plurality of nozzles, in which an actuator is driven by a drive signal to displace a diaphragm to discharge a liquid droplet. An abnormality inspection method is provided, wherein an inspection signal is supplied to an actuator of an abnormality inspection target nozzle to be inspected for ejection abnormality among a plurality of nozzles, and nozzles are determined based on residual vibration of a diaphragm generated when the actuator is driven. An inspection process for inspecting an ejection abnormality, and an ejection process for ejecting liquid droplets by supplying a drive signal to all or a part of the actuators of the plurality of nozzles excluding the nozzle to be inspected for abnormality. And performing in parallel. In the invention configured as described above, the printing with the real-time nozzle inspection can be performed in the same time as the conventional printing without the real-time nozzle inspection.

A plurality of constituent elements of each aspect of the present invention described above are not indispensable, and some or all of the effects described in the present specification are to be solved to solve part or all of the above-described problems. In order to achieve the above, it is possible to appropriately change, delete, replace with another new component, and partially delete the limited contents of some of the plurality of components. In order to solve part or all of the above-described problems or to achieve part or all of the effects described in this specification, technical features included in one embodiment of the present invention described above. A part or all of the technical features included in the other aspects of the present invention described above may be combined to form an independent form of the present invention.

The figure which shows the droplet discharge apparatus concerning 1st Embodiment of this invention. Sectional drawing of the periphery of the nozzle provided in an ejection head. 2 is a timing chart illustrating an example of the operation of the printer illustrated in FIG. 1. The figure which shows the droplet discharge apparatus concerning 2nd Embodiment of this invention.

FIG. 1 is a block diagram illustrating a configuration of a printer as a droplet discharge device according to a first embodiment of the present invention. The printer 1 includes an ejection head 10 and a main substrate 20 as shown in FIG. The discharge head 10 includes a plurality of discharge mechanisms 11 and a head IC (Integrated Circuit) 12 that controls the discharge mechanisms 11.

FIG. 2 is a cross-sectional view of the periphery of a nozzle provided in the ejection head.
The plurality of ejection mechanisms 11 provided in the ejection head 10 all have the same configuration. That is, each discharge mechanism 11 includes a diaphragm 111 and a plurality of piezoelectric elements 112 as shown in FIG.
1 is laminated, a cavity (pressure chamber) 113 in which ink as a liquid is filled and the internal pressure is increased / decreased by displacement of the vibration plate 111, and communicated with the cavity 113. In addition, a nozzle 114 that discharges ink as droplets by increasing or decreasing the pressure in the cavity 113, a nozzle substrate 115 on which the nozzle 114 is formed,
And a cavity substrate 116. The cavity substrate 116 is formed in a predetermined shape as shown in the figure, whereby a cavity 113 and a reservoir 117 communicating with the cavity 113 are formed. The reservoir 117 is connected to the ink cartridge 30 via the ink supply tube 118. The piezoelectric actuator 112 includes a comb-shaped first electrode 1122 and a second electrode 1123 which are arranged to face each other, and the electrodes (the first electrode 1122 and the second electrode 1).
123) and the piezoelectric elements 1121 arranged alternately. Moreover, the piezoelectric actuator 112 has one end side thereof as shown in FIG.
11 is joined.

In the piezoelectric actuator 112 having such a configuration, when a drive signal or an inspection signal is applied between the first electrode 1122 and the second electrode 1123, the piezoelectric actuator 112 expands and contracts in the vertical direction as indicated by arrows in FIG. The mode to use is used. Therefore, in the piezoelectric actuator 112, when a drive signal is applied, the diaphragm 111 is displaced by the expansion and contraction of the piezoelectric actuator 112, the pressure in the cavity 113 is changed, and an ink droplet is ejected from the nozzle 114. It is like that. Specifically, the volume of the cavity 113 is enlarged to draw ink, and then the volume of the cavity 113 is reduced to eject ink droplets. On the other hand, when the inspection signal is applied, the diaphragm 111 is displaced by the expansion and contraction of the piezoelectric actuator 112, but the displacement amount is such that ink droplets are not ejected from the nozzle 114. The drive control of the piezoelectric actuator 112 is performed by the head IC 12 based on various signals from the main substrate 20.

Next, before describing the configuration of the head IC 12, the configuration of the main substrate 20 will be described. As shown in FIG. 1, the main board 20 includes a nozzle control signal generation circuit 21, a nozzle voltage detection circuit 22, an inspection signal generation circuit 23, a drive signal generation circuit 24, an abnormality determination circuit 25,
And an offset power supply 26. Among these, the drive signal generation circuit 24 generates a drive signal having a head drive waveform for driving the piezoelectric actuator 112 of the discharge head 10 to discharge ink droplets as droplets. Further, the inspection signal generation circuit 23 includes the nozzle 1
14 generates an inspection signal having a head inspection waveform for causing the diaphragm 111 to vibrate slightly without ejecting ink droplets.

The drive signal generation circuit 24 has a drive capability sufficient to drive all the actuators 112 provided in the ejection head 10 and eject ink droplets. On the other hand, the inspection signal generation circuit 23 has a drive capability that can drive only one actuator 112 and execute an ejection abnormality inspection of the nozzle 114. As described in detail later, the reason for providing a difference in drive capability in this way is that nozzles 114 that do not eject ink droplets in parallel with the ejection of ink droplets from nozzles 114 (ejection process) according to a print job. This is because an abnormal discharge is inspected for one of them (inspection process). Therefore, the inspection signal generation circuit 23 can be configured with a relatively small and inexpensive transistor.

A nozzle control signal generation circuit 21 ejects ink droplets according to a print job.
4 is generated and a nozzle control signal for setting a nozzle 114 that performs ejection abnormality inspection among nozzles 114 that do not eject ink droplets is generated, and the switch control unit 1 of the head IC 12 is generated.
To 21. Based on the nozzle control signal, the switch control unit 121 controls the opening and closing of various switches provided in the head IC 12, so that the drive signal and inspection signal supply destination (actuator 112) is appropriately switched as described above.

In addition, the nozzle voltage detection circuit 22 detects an inspection voltage for determining an ejection abnormality of the nozzle 114 (abnormality inspection target nozzle) which is supplied with an inspection signal and is an inspection target for abnormal discharge, and abnormally detects the detection result. The determination circuit 25 is given. Then, the abnormality determination circuit 25 determines whether or not a discharge abnormality has occurred in the inspection target nozzle 114 based on the inspection voltage. The inspection voltage will be described in parallel with the description of the configuration of the next head IC 12.

The head IC 12 is an SOC (System on a chip) or the like in which a digital signal processing circuit, an analog signal processing circuit, a RAM, and the like are included in a single semiconductor integrated circuit. In the head IC 12, a drive switch D, an inspection switch T, changeover switches S 1 and S 2, and a resistor R are provided for each ejection mechanism 11, and the switch control unit 121 opens and closes the switches D, T, S 1, and S 2. Is controlled based on the nozzle control signal supplied from the nozzle control signal generation circuit 21. In FIG. 1, only the first discharge mechanism 11a, the second discharge mechanism 11b, and the third discharge mechanism 11c among the plurality of discharge mechanisms 11 are illustrated.

In the first discharge mechanism 11a, the resistor Ra, the actuator 112a, the offset power source 26, and the ground are connected in series. A driving signal generation circuit 24 is connected to the resistor Ra via a driving switch Da and an inspection signal generation circuit 23 is connected via an inspection switch Ta. The drive switch Da is a field effect transistor in which a source and a drain are connected in series between the resistor Ra and the drive signal generation circuit 24. The inspection switch Ta is a field effect transistor in which a source and a drain are connected in series between the resistor Ra and the inspection signal generation circuit 23.

The changeover switch S1a is connected in parallel with the resistor Ra. Further, one terminal of the changeover switch S2a is connected between the resistor Ra and the actuator 112a, and the other terminal of the changeover switch S2a is connected to the nozzle voltage detection circuit 22. These change-over switches S1a and S2a are also field effect transistors in which the source and the drain are connected in series like the drive switch Da and the inspection switch Ta. Note that the voltage drop due to the resistance in these switches Da, Ta, S1a, S2a is ignored.

When the drive switch Da, the inspection switch Ta, and the changeover switches S1a and S2a are switched to the “closed”, “open”, “closed”, and “open” states according to the open / close signal from the switch control unit 121, respectively. A drive signal is given to the actuator 112a of the first ejection mechanism 11a, and ink droplets are ejected from the nozzles 114 of the first ejection mechanism 11a. On the other hand, when the drive switch Da, the inspection switch Ta, and the changeover switches S1a and S2a are switched to the “open”, “closed”, “open”, and “closed” states according to the open / close signal from the switch control unit 121, respectively. An inspection signal is given to the actuator 112a of the one discharge mechanism 11a and the resistance R
A voltage generated at both ends of a, that is, an inspection voltage is detected by the nozzle voltage detection circuit 22. This inspection voltage is sent to the abnormality determination circuit 25. Then, the abnormality determination circuit 25 obtains the residual vibration of the diaphragm 111 that occurs after application of the inspection signal based on the inspection voltage, and inspects whether or not the nozzle ejection abnormality has occurred based on the residual vibration.

Such a configuration is the same for the ejection mechanisms 11 other than the first ejection mechanism 11a. For convenience of explanation of the operation of the printer 1, the second ejection mechanism 11b and the third ejection mechanism in FIG.
The discharge mechanism 11c is also given a corresponding symbol.

FIG. 3 is a timing chart showing an example of the operation of the printer shown in FIG. In the operation case shown in the figure, ink droplets are ejected only from the second ejection mechanism 11b following ejection of ink droplets from only the first ejection mechanism 11a.

In this case, the switch control unit 121 switches the drive switch Da, the inspection switch Ta, and the changeover switches S1a and S2a to the “closed”, “open”, “closed”, and “open” states, respectively, and the actuator of the first discharge mechanism 11a. A drive signal is applied to 112a. This is the first
During the period P1, the potential applied to the actuator 112a of the first ejection mechanism 11a becomes H level, and ink droplets are ejected from the first ejection mechanism 11a. In the subsequent second period P2, the potential applied to the actuator 112a returns to the M level (<H level). In this embodiment, the switch control unit 121 sets the drive switch Db, the inspection switch Tb, and the changeover switches S1b and S2b to the “open”, “closed”, “open”, and “closed” states in the first period P1, respectively. The inspection signal is applied to the actuator 112b of the second discharge mechanism 11b. As a result, the potential applied to the actuator 112b of the second ejection mechanism 11b during the first period P1 becomes L level (<M level <H level), and the inspection voltage is detected by the nozzle voltage detection circuit 22 in the subsequent second period P2. Further, the abnormality determination circuit 25 checks whether or not the nozzle discharge abnormality has occurred in the second discharge mechanism 11b. Thus, during the first period P1 and the second period P2, the nozzle 114 of the second discharge mechanism 11b corresponds to the “abnormality inspection target nozzle” of the present invention. The switch control unit 121 includes a drive switch Dc and an inspection switch T.
c, the changeover switches S1a and S2a are respectively switched to the “open” state, and the third discharge mechanism 11c
In contrast, neither the drive signal nor the inspection signal is applied. The same applies to other discharge mechanisms 11 (not shown). These points are the same in the next periods P3 and P4.

Subsequently, the operation opposite to the above is performed. That is, the switch control unit 121 switches the drive switch Db, the inspection switch Tb, and the changeover switches S1b and S2b to the “closed”, “open”, “closed”, and “open” states, respectively, and the actuator 112b of the second discharge mechanism 11b.
A drive signal is applied to. As a result, the potential applied to the actuator 112b of the second ejection mechanism 11b during the third period P3 becomes H level, and ink droplets are ejected from the nozzles 114 of the second ejection mechanism 11b. In the subsequent fourth period P4, the potential applied to the actuator 112b returns to the M level. Further, in the third period P3, the switch control unit 121 sets the drive switch Da, the inspection switch Ta, and the changeover switches S1a and S2a to “open”, “closed”, “
The inspection signal is applied to the actuator 112a of the first discharge mechanism 11a by switching between the “open” and “closed” states. Thereby, during the third period P3, the actuator 1 of the first discharge mechanism 11a.
The potential applied to 12a is at the L level, the inspection voltage is detected by the nozzle voltage detection circuit 22 in the subsequent fourth period P4, and further, whether or not the nozzle discharge abnormality has occurred in the first discharge mechanism 11a by the abnormality determination circuit 25 Inspected for no. Thus, during the third period P3 and the fourth period P4, the nozzle 114 of the first discharge mechanism 11a is the “abnormality inspection target nozzle” of the present invention.
It corresponds to.

As described above, according to the present embodiment, in addition to the drive signal generation circuit 24 that generates a drive signal for ejecting ink droplets from the nozzle 114, an inspection signal for inspecting an ejection abnormality of the nozzle 114 is generated. An inspection signal generation circuit 23 is provided, and either a drive signal or an inspection signal can be input to the actuator 112. For this reason, it is possible to check the ejection abnormality of the nozzle 114 without being restricted by the ejection timing of the ink droplet by the drive signal. For example, in the case shown in FIG. 3, the discharge abnormality of the nozzle 114 of the second discharge mechanism 11b is inspected (inspection step) in parallel with the discharge of ink droplets from the nozzle 114 by the first discharge mechanism 11a (inspection step). In parallel with the ejection of ink droplets from the nozzle 114 by the second ejection mechanism 11b (ejection process), the ejection abnormality of the nozzle 114 of the first ejection mechanism 11a can be inspected (inspection process). In this way, it is possible to inspect the ejection abnormality for each nozzle 114 individually, and an accurate inspection can be performed.

In the conventional apparatus, an independent inspection signal generation circuit is not provided, and the drive signal and the inspection signal are generated by the drive signal generation circuit. Therefore, in order to perform the real-time nozzle inspection, it is necessary to sequentially input the drive signal and the inspection signal, and as a result, 1 during a certain period (corresponding to the period CT in FIG. 3). Only one nozzle can be inspected, which causes a long printing time. On the other hand, in the above embodiment, the ejection abnormality can be inspected for the two nozzles 114 during the period CT as shown in FIG. As a result, even if printing is performed with real-time nozzle inspection, printing can be performed in the same time as conventional printing without real-time nozzle inspection.

FIG. 4 is a block diagram illustrating a configuration of a printer as a droplet discharge device according to the second embodiment of the present invention. This embodiment is largely different from the embodiment shown in FIG. 1 in that the resistor R and the changeover switch S1 are omitted, and the check switch T is turned on in an element-specific size between the source and drain in the closed state. A voltage is generated at both ends of the on-resistance, and a test voltage is used. On the other hand, other configurations are the same. Therefore, about the same structure, the same code | symbol is attached | subjected and description of a structure is abbreviate | omitted.

In this embodiment, the switch control unit 121 includes, for example, a drive switch Da and an inspection switch T.
a, the changeover switch S2a is switched to the “closed”, “open” and “open” states, respectively, and a drive signal is applied to the actuator 112a of the first discharge mechanism 11a. As a result, as shown in FIG. 3, the potential applied to the actuator 112a of the first ejection mechanism 11a during the first period P1 becomes H level, and ink droplets are ejected from the first ejection mechanism 11a. In the subsequent second period P2, the potential applied to the actuator 112a returns to the M level (<H level). In the first period P1, the switch controller 121 switches, for example, the drive switch Db, the inspection switch Tb, and the changeover switch S2b to the “open”, “closed”, and “closed” states, respectively.
An inspection signal is applied to the actuator 112b of the discharge mechanism 11b. As a result, the first period P
1, the potential applied to the actuator 112b of the second discharge mechanism 11b is at the L level (<
Whether or not the inspection voltage is detected by the nozzle voltage detection circuit 22 in the subsequent second period P2, and further whether or not the nozzle discharge abnormality has occurred in the second discharge mechanism 11b by the abnormality determination circuit 25. Is inspected.

Subsequently, for example, the switch control unit 121 includes a drive switch Db, an inspection switch Tb,
When the changeover switch S2b is switched to the “closed”, “open”, and “open” states, a drive signal is applied to the actuator 112b of the second discharge mechanism 11b. As a result, the third period P
3, the potential applied to the actuator 112 b of the second ejection mechanism 11 b becomes H level, and ink droplets are ejected from the second ejection mechanism 11 b. In the subsequent fourth period P4, the potential applied to the actuator 112b returns to the M level. Further, during this third period P3, for example, when the switch control unit 121 switches the driving switch Da, the inspection switch Ta, and the changeover switch S2a to the “open”, “closed”, and “closed” states, respectively, the first discharge mechanism 11a An inspection signal is applied to the actuator 112a. As a result, the first discharge mechanism 1 during the third period P3.
The potential applied to the actuator 112a of 1a becomes L level, and the inspection voltage is detected by the nozzle voltage detection circuit 22 in the subsequent fourth period P4, and further, the nozzle discharge abnormality occurs in the first discharge mechanism 11a by the abnormality determination circuit 25. It is inspected whether it is doing. As described above, although the second embodiment has a simpler configuration than the first embodiment, the same operational effects as those of the first embodiment can be obtained. Therefore, the second embodiment is more advantageous than the first embodiment from the viewpoint of device cost.

The present invention is not limited to the above-described embodiment, and various modifications can be made to the above-described one without departing from the spirit of the present invention. For example, in the above embodiment, the number of ejection mechanisms 11 that eject ink droplets in parallel with the ejection abnormality inspection is one, but the number of ejection mechanisms 11 is “(total number of ejection mechanisms 11) −1”. It is optional if In short, while ejecting ink droplets with one or a plurality of ejection mechanisms 11, a different ejection mechanism 11 different from them may be inspected for ejection abnormalities.

In the above embodiment, the present invention is applied to a droplet discharge device that discharges ink droplets. However, the present invention is applied to a droplet discharge device having a discharge mechanism that discharges droplets other than ink droplets. May be applied. For example, a droplet discharge device that forms a planar structure or a three-dimensional structure with discharged droplets is also included in the scope of application of the present invention. Further, the droplet may be any material constituting a planar structure or a three-dimensional structure. Furthermore, the present invention may be applied to a droplet discharge device that discharges a processing liquid for performing processing (cleaning, etching, etc.) at a droplet landing position.

In the above embodiment, the inspection process is performed during execution of an arbitrary print job.
The printer 1 may perform the inspection process while printing a predetermined inspection image.

As described above, in this embodiment, the ink droplet corresponds to an example of the “liquid droplet” of the present invention. The inspection signal generation circuit 23 and the drive signal generation circuit 24 correspond to examples of the “inspection signal generation unit” and the “drive signal generation unit” of the present invention, respectively. Also,
The nozzle voltage detection circuit 22 and the abnormality determination circuit 25 are each a “residual vibration inspection unit” of the present invention.
And a combination of these functions as an “abnormality inspection unit” of the present invention. The head IC 12 functions as a “switching unit” of the present invention. The inspection switch T corresponds to an example of the “switch” of the present invention, and has a function of switching between application and non-application of the inspection signal to the actuator 112. Furthermore, the “inspection process” and “
The “discharge process” constitutes the “abnormality inspection method in the droplet discharge apparatus” of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Printer (droplet discharge apparatus), 10 ... Discharge head, 11 ... Discharge mechanism, 11a ... 1st
Discharge mechanism, 11b ... second discharge mechanism, 11c ... third discharge mechanism, 12 ... head IC, 20 ... main substrate, 21 ... nozzle control signal generation circuit, 22 ... nozzle voltage detection circuit, 23 ... inspection signal generation circuit, 24 ... driving signal generation circuit, 25 ... determination circuit, 111 ... diaphragm, 112, 112a,
112b ... piezoelectric actuator, 114 ... nozzle, 121 ... switch control unit, D, Da
, Db ... drive switch, P1 ... first period, P2 ... second period, P3 ... third period, R, Ra ...
Resistance, T, Ta, Tb, Tc ... Inspection switch

Claims (6)

An ejection head having a plurality of nozzles, in which an actuator is driven by a drive signal to displace a diaphragm and eject liquid droplets;
A drive signal generator for generating the drive signal;
An inspection signal generator for generating an inspection signal;
An abnormality inspection unit for inspecting ejection abnormality of the nozzle based on residual vibration of the diaphragm generated when the actuator is driven by the inspection signal;
A droplet discharge device comprising: a switching unit that selectively switches between input of the drive signal to the actuator and input of the inspection signal to the actuator. The droplet discharge device according to claim 1,
The inspection signal generation unit provides the inspection signal to the actuators of other nozzles in parallel with the ejection of droplets from one of the plurality of nozzles,
The abnormality inspection unit is a liquid droplet ejection device that determines ejection abnormality of the other nozzle. The droplet discharge device according to claim 1 or 2,
The switching unit includes a switch that is connected in series to the inspection signal generation unit and the actuator and switches between application and non-application of the inspection signal to the actuator,
The abnormality inspection unit measures a voltage generated between both ends of a resistor existing between the inspection signal generation unit and the actuator when the inspection signal is applied to the actuator via the switch, thereby measuring residual vibration. A liquid droplet ejection apparatus, comprising: a residual vibration inspection unit that inspects the nozzles; and a determination unit that determines whether a discharge abnormality of the nozzle has occurred based on the residual vibration inspected by the residual vibration inspection unit. The droplet discharge device according to claim 3,
The switch is a transistor;
The droplet discharge device, wherein the resistance is an on-resistance of the transistor. The droplet discharge device according to claim 3 or 4,
The switch is provided for each actuator,
The switching unit includes a switch control unit that controls opening and closing of the plurality of switches,
The switch control unit closes one switch of the plurality of switches and opens another switch to input the inspection signal only to the actuator connected to the one switch. An abnormality inspection method for inspecting the ejection abnormality of the nozzle in a droplet ejection apparatus having a plurality of nozzles, in which a diaphragm is displaced by driving an actuator by a drive signal to eject a liquid droplet,
Inspecting ejection abnormality of the nozzle based on residual vibration of the diaphragm generated when the actuator is driven by supplying an inspection signal to the actuator of the abnormality inspection target nozzle to be inspected for ejection abnormality among the plurality of nozzles An inspection process to
A discharge step of discharging droplets by supplying the drive signal to all or a part of the actuators of the plurality of nozzles excluding the abnormal inspection target nozzle,
An abnormality inspection method for a droplet discharge device, wherein the inspection step and the discharge step are performed in parallel.

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