JP2011206958A - Liquid injection device, liquid injection head and method of detecting coming-out of nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid injection device capable of reducing the size while enabling detection of coming-out of nozzles, a liquid injection head and a method of detecting coming-out of the nozzles.SOLUTION: The liquid injection device 10 includes: a liquid injection head 30 having a nozzle plate 32 in which the plurality of nozzles 32a injecting liquid toward outside are formed; paired electrodes 51a, 51b at least part of which is provided within the nozzle plate 32; and a detection means 535 electrically connected to the electrodes 51a, 51b and detecting whether or not injection of liquid from the nozzles 32a is possible, based on electric power obtained from the electrodes 51a, 51b in accordance with a state of a meniscus of the liquid. One electrode 51a is provided with respect to each nozzle 32a, and the other electrode 51b is provided opposing to the one electrode 51a sandwiching the nozzle 32a and serves as a common electrode with respect to the plurality of nozzles 32a.

Description

  The present invention relates to a liquid ejecting apparatus, a liquid ejecting head, and a nozzle missing detection method.

In an ink jet printer, ink droplets are not ejected from the nozzles for reasons such as thickening the ink inside any nozzle of the print head.
The phenomenon of “nozzle missing” may occur. As a technique for detecting such nozzle omission, there is a technical content disclosed in Patent Document 1. In Patent Document 1, a nozzle detection device having a pair of opposed electrodes is provided, and a nozzle is dropped by ejecting ink droplets by positioning a print head on the nozzle detection device. A method for detecting whether or not there is disclosed.

JP 2009-45809 A

In the above-described Patent Document 1, the nozzle detection device is disclosed with respect to a configuration provided at a portion (one end side of the platen) that does not affect printing on the print medium. However, even when the nozzle detection device is installed at such a site, space is required for the installation. Therefore, there arises a problem that it is difficult to reduce the size of the printer.

The present invention has been made based on the above-described circumstances, and an object of the present invention is to provide a liquid ejecting apparatus, a liquid ejecting head, and a nozzle missing detection that can detect a nozzle missing and can be downsized. Try to provide a method.

In order to solve the above problems, a liquid ejecting apparatus of the present invention includes a liquid ejecting head including a nozzle plate in which a plurality of nozzles for ejecting liquid toward the outside are formed, and at least a part of the nozzle plate. A pair of electrodes provided inside, and whether or not the liquid can be ejected from the nozzle based on the electric power obtained from the electrode according to the state of the liquid meniscus while being electrically connected to the electrode Detecting means for detecting, wherein one electrode of the pair of electrodes is provided for each nozzle, and the other electrode of the pair of electrodes is opposed to the one electrode across the nozzle. And is a common electrode for a plurality of nozzles.

In the case of such a configuration, in the pair of electrodes facing each other with the nozzle interposed therebetween, the power changes when the liquid is ejected from the nozzle. Accordingly, the detection means can detect whether or not the liquid can be ejected from the nozzle based on the electric power obtained from the pair of electrodes.

Thus, at least a part of the pair of electrodes is provided inside the nozzle plate. For this reason, the pair of electrodes are provided integrally with the nozzle plate. Thereby, it is possible to save space in the liquid ejecting apparatus. That is, in the conventional configuration, since the nozzle detection device is installed on one end side of the platen, space is required for the installation. On the other hand, in the present invention, since at least a part of the electrodes is provided inside the nozzle plate, the pair of electrodes are integrated with the nozzle plate, thereby providing the nozzle detection device separately. So that no extra space is required. Therefore, it is possible to reduce the size of the liquid ejecting apparatus.

One electrode is provided for each nozzle. Therefore, it is possible to simultaneously detect whether or not the liquid can be ejected from all the nozzles. Thereby, it is possible to detect whether or not the liquid can be ejected from the nozzle in a short time. Further, since it is possible to detect whether or not the liquid can be ejected from all the nozzles, it is possible to perform the detection even when the liquid is ejected toward the ejection target.

According to another aspect of the present invention, in the above-described invention, the detection unit is configured to detect the liquid from the nozzle based on a detection value corresponding to a change in capacitance when the liquid passes between the pair of electrodes. It is preferable to detect whether injection is possible.

In such a configuration, the capacitance of the pair of electrodes facing each other across the nozzle changes depending on whether or not the liquid is supplied to the nozzle. The detection means can detect a change in capacitance based on the electric power obtained from the pair of electrodes, and can detect whether the detection means can eject liquid from the nozzle. It becomes.

Further, according to another aspect of the present invention, in each of the above-described inventions, it is preferable that the detection unit performs detection when the liquid is ejected from the liquid ejecting head toward the ejection target.

In the case of such a configuration, when the liquid is ejected toward the ejection target object, it is detected whether or not the liquid can be ejected from the nozzle by the detection means. Therefore, the detection by the detection means does not require a separate time, and the processing efficiency of the liquid ejecting apparatus can be increased.

According to another invention, in addition to the above-described inventions, the detection means further includes a detection signal based on the power obtained from the pair of electrodes when the meniscus is expected to be in a normal position, and the meniscus is normal. A detection signal based on the power obtained from the pair of electrodes when it is expected that the liquid does not exist in the position, and the meniscus state is detected based on at least one of the detection signals. It is preferable to select any one of the maintenance operations that are to be discharged.

In such a configuration, detection is performed based on at least one of the detection signals described above to detect whether the meniscus is in a normal position or not in a normal position. It becomes possible.

Further, in another invention, in addition to each of the above-described inventions, the detection means preferably includes an oscillation circuit capable of oscillating at a natural frequency that varies depending on the presence or absence of liquid.

When configured in this manner, electric power whose natural frequency changes depending on the presence or absence of liquid is applied between the pair of electrodes. Therefore, it is possible to easily determine the meniscus state by detecting a change in the natural frequency.

A liquid ejecting head according to another aspect of the present invention is a liquid ejecting head including a nozzle plate in which a plurality of nozzles for ejecting liquid toward the outside is formed, at least a part of the nozzle plate being Depending on the state of the liquid meniscus,
A pair of electrodes that output electric power for detecting whether or not the liquid can be ejected from the nozzle, and one electrode of the pair of electrodes is provided for each nozzle, The other electrode of the electrodes is preferably provided so as to face the one electrode across the nozzle and is a common electrode for the plurality of nozzles.

In the case of such a configuration, in the pair of electrodes facing each other with the nozzle interposed therebetween, the power changes when the liquid is ejected from the nozzle. Then, based on the electric power obtained from the pair of electrodes, by detecting with the detecting means, it is possible to detect a change in electric power and detect whether or not the liquid can be ejected from the nozzle. Become.

Thus, at least a part of the pair of electrodes is provided inside the nozzle plate. For this reason, the pair of electrodes are provided integrally with the nozzle plate. Accordingly, by using the liquid ejecting head for the liquid ejecting apparatus, it is possible to save the space of the liquid ejecting apparatus, and to reduce the size of the liquid ejecting apparatus.

One electrode is provided for each nozzle. Therefore, it is possible to simultaneously detect whether or not the liquid can be ejected from all the nozzles. Thereby, it is possible to detect whether or not the liquid can be ejected from the nozzle in a short time. Further, since it is possible to detect whether or not the liquid can be ejected from all the nozzles, it is possible to perform the detection even when the liquid is ejected toward the ejection target.

According to another aspect of the present invention, there is provided a method for detecting missing nozzles in a liquid ejecting head including a nozzle plate in which a plurality of nozzles for ejecting liquid toward the outside is formed. In this method, the liquid ejecting head includes a pair of electrodes provided at least partially inside the nozzle plate, and one of the pair of electrodes is provided for each nozzle. The other electrode of the pair of electrodes is provided so as to be opposed to the one electrode across the nozzle and is a common electrode for the plurality of nozzles. It is preferable to include a detection step of detecting whether or not the liquid can be ejected from the nozzle based on the electric power obtained from the electrode according to the state of the meniscus.

In the case of such a configuration, in the pair of electrodes facing each other with the nozzle interposed therebetween, the power changes when the liquid is ejected from the nozzle. Thereby, in the detection step,
Based on the electric power obtained from the pair of electrodes, it is possible to detect whether or not the liquid can be ejected from the nozzle.

Thus, at least a part of the pair of electrodes is provided inside the nozzle plate. For this reason, the pair of electrodes are provided integrally with the nozzle plate. Thereby, it is possible to save space in the liquid ejecting apparatus. That is, in the conventional configuration, since the nozzle detection device is installed on one end side of the platen, space is required for the installation. On the other hand, in the present invention, since at least a part of the electrodes is provided inside the nozzle plate, the pair of electrodes are integrated with the nozzle plate, thereby providing the nozzle detection device separately. So that no extra space is required. Therefore, it is possible to reduce the size of the liquid ejecting apparatus.

One electrode is provided for each nozzle. Therefore, it is possible to simultaneously detect whether or not the liquid can be ejected from all the nozzles. Thereby, it is possible to detect whether or not the liquid can be ejected from the nozzle in a short time. Further, since it is possible to detect whether or not the liquid can be ejected from all the nozzles, it is possible to perform the detection even when the liquid is ejected toward the ejection target.

1 is a schematic diagram illustrating a configuration of a printer according to an embodiment of the present invention. FIG. 2 is an exploded perspective view illustrating a configuration of a print head in the printer of FIG. 1. It is sectional drawing which shows the structure of the print head of FIG. It is a figure which transparently shows arrangement | positioning of the nozzle and electrode which concern on 1st Embodiment. It is a figure which shows the cross-sectional shape of a nozzle plate, and the structure of an oscillation circuit. It is a figure which shows transparently the positional relationship of a nozzle and an electrode. It is a block diagram which shows schematic structure of a control part. It is sectional drawing which shows the change of the height position of a meniscus. It is sectional drawing which shows the state which has the height position of a meniscus in a middle position. It is a figure which shows the mode of a change of a detection signal. It is a figure which transparently shows arrangement | positioning of the nozzle and electrode which concern on 2nd Embodiment. It is a block diagram which shows schematic structure of the control part which concerns on 2nd Embodiment.

(First embodiment)
Hereinafter, a printer 10 and a liquid ejecting method as a liquid ejecting apparatus according to a first embodiment of the invention will be described with reference to FIGS. 1 to 10. The printer 10 according to the present embodiment is an ink jet printer. However, the ink jet printer may be an apparatus that employs any ejection method as long as the apparatus is capable of printing by ejecting ink.

In the following description, the lower side refers to the side where the printer 10 is installed, and the upper side refers to the side away from the installed side. Further, the opening side of the nozzle 32a with respect to the pressure generation chamber 315 is defined as a lower side, and the opposite side is defined as an upper side. Further, the side on which the print medium P is supplied is described as a feeding side (rear end side), and the side on which the print medium P is discharged is described as a paper discharge side (front side). In addition, a direction in which a carriage 21 described later moves is a main scanning direction, a direction orthogonal to the main scanning direction, and a direction in which the print medium P is conveyed is a sub-scanning direction.

<Schematic Configuration of Printer 10>
As shown in FIG. 1, the printer 10 includes a housing unit (not shown), a carriage mechanism 20, a paper transport mechanism 40, a nozzle inspection device 50, a control unit 60, and the like as main components.

Among these, the carriage mechanism 20 includes a carriage 21 and a carriage motor (CR
A motor 22), a belt 23, a gear pulley 24, a driven pulley 25, and a carriage shaft 26 (corresponding to a sliding shaft). Among these, the carriage 21 can mount ink cartridges 27 of the respective colors. As shown in FIG. 1, a print head 30 (corresponding to an example of a liquid ejecting head) capable of ejecting ink droplets is provided on the lower surface of the carriage 21. Details of the configuration of the print head 30 will be described later. Also, the ink
This corresponds to an example of a liquid.

The belt 23 is an endless belt, and a part of the belt 23 is fixed to the back surface of the carriage 21. The belt 23 is stretched by a gear pulley 24 and a driven pulley 25.

The carriage 21 can be mounted with an ink cartridge 27 that stores ink (corresponding to liquid) of each color (for example, cyan, magenta, yellow, and black). The number of colors of the ink cartridge 27 is not limited to the above four colors, and may be three colors of cyan, magenta, and yellow, or five or more colors.

Further, as shown in FIG. 1, the paper transport mechanism 40 includes a PF motor 41 for transporting the print medium P (corresponding to the ejection target), and a paper feed roller 42 for feeding plain paper or the like. is doing. A pair of PF rollers (not shown) for conveying / clamping the print medium P is provided on the paper discharge side with respect to the paper feed roller 42. A platen (not shown) and the above-described print head 30 are disposed on the paper discharge side of the PF roller pair so as to face each other in the vertical direction.

<Details of Configuration of Print Head 30>
Details of the configuration of the print head 30 of the carriage mechanism 20 will be described with reference to FIGS. As shown in FIG. 2, the print head 30 includes a head body 31 and a nozzle plate 32. 2 and 3, the head main body 31 includes a flow path forming substrate 311, an elastic film 312, and an insulating film 3 that are present above the nozzle plate 32 in order from the bottom.
13 and a protective substrate 314 are laminated.

The head main body 31 includes a pressure generation chamber 315, an ink supply path 316, a reservoir 31.
A portion to be a liquid flow path such as 7 is formed. Among these, a large number of pressure generation chambers 315 are provided along the sub-scanning direction of the printer 10. Adjacent pressure generating chambers 31
5 is provided with a partition wall 315a. One pressure generation chamber 315 is provided for each nozzle 32a described later.

The ink supply path 316 is a part connecting the pressure generation chamber 315 and the reservoir 317, and is a channel for supplying ink from the reservoir 317 to the pressure generation chamber 315. Therefore, the same number of ink supply paths 316 as the pressure generation chambers 315 are provided. As shown in FIG. 3, the ink supply path 316 is formed with a flow path diameter that is narrower than the width dimension of the pressure generating chamber 315. For this reason, the ink supply path 316 generates a certain flow path resistance when ink is introduced into the pressure generating chamber 315.

The reservoir 317 communicating with the ink supply path 316 is provided along the direction (longitudinal direction) in which the plurality of pressure generating chambers 315 are arranged. Therefore, the reservoir 317 is provided in a long shape, and for example, one reservoir 317 is provided in one nozzle row 32b. Reservoir 3
Reference numeral 17 denotes a portion where ink is introduced before the ink is introduced into the pressure generating chamber 315 via the ink supply path 316.

Further, on the insulating film 313, the piezoelectric element 3 is provided for each pressure generating chamber 315.
3 is provided. The piezoelectric element 33 corresponds to an example of a vibration applying unit. The piezoelectric element 33 includes a lower electrode film 331 formed by stacking platinum and iridium, a piezoelectric layer 332 made of, for example, lead zirconate titanate (PZT), and iridium (Ir), for example.
The upper electrode film 333 is made of Although the lower electrode film 331 is a common electrode and is provided in a large area, the piezoelectric layer 332 and the upper electrode film 333 are provided for each pressure generation chamber 315 and are adjacent to each other. A gap with a predetermined gap is provided between the body layer 332 and the upper electrode film 333.

Further, lead electrodes 334 made of, for example, gold (Au) are connected to the upper electrode film 333, and the lead electrodes 334 are connected to a drive circuit (not shown). A voltage is selectively applied to each piezoelectric element 33 via the lead electrode 334.

Further, in the present embodiment, the nozzle plate 32 is formed of a material that is insulative with respect to electric power conducted to a wiring pattern to be described later. Examples of such a material include silicon and various resins. A wiring pattern is embedded in the nozzle plate 32. Details thereof will be described later.

<About the configuration of the nozzle inspection device>
Next, the configuration of the nozzle inspection device 50 will be described. As shown in FIGS. 4 and 5, the nozzle inspection device 50 includes a pair of electrodes 51 a and 51 b, a wiring pattern 52, and an oscillation circuit 5.
3.

In the present embodiment, as shown in FIG. 5, the pair of electrodes 51 a and 51 b is configured to be embedded in the nozzle plate 32. Here, the pair of electrodes 51a and 51b being embedded in the nozzle plate 32 means that in the cross-sectional view of the electrodes 51a and 51b shown in FIG. 5, the periphery of the electrodes is covered with the material constituting the nozzle plate 32. It means that the state is. Further, a capacitor is constituted by the pair of electrodes 51a and 51b described above. As shown in FIGS. 4 and 5, a pair of electrodes 51a and 51b is provided with a nozzle 32a interposed therebetween. The pair of electrodes 51a and 51b are provided long so as to extend along the direction of the nozzle row 32b. The length of the pair of electrodes 51a and 51b in the longitudinal direction is such that all the nozzles 3 in the nozzle row 32b are interposed between the pair of electrodes 51a and 51b.
The length is such that 2a exists.

In the following description, when it is not necessary to distinguish the electrode 51a and the electrode 51b, they are simply referred to as the electrode 51. Moreover, as shown in FIG. 6, you may employ | adopt the structure where at least one of the electrode 51a and the electrode 51b exists with respect to one nozzle row 32b.

The pair of electrodes 51a and 51b are connected in series to the power source, and power from the oscillation circuit 53 as shown in FIG. 5 is applied to the pair of electrodes 51a and 51b. The oscillation circuit 53 is a Colpitts oscillation circuit of a positive feedback circuit connected to the electrodes 51a and 51b. The oscillation circuit 53 includes a coil 531 connected in parallel to the pair of electrodes 51a and 51b, a buffer 532 connected in parallel to the coil 531, a capacitor 533 connected to one end of the coil 531 and the ground, A capacitor 534 connected to the other end of the coil 531 and the ground. The oscillation circuit 53 is attached to the outside of the nozzle plate 32 in the print head 30. However, the oscillation circuit 53 may be embedded in the nozzle plate 32. Further, the oscillation circuit 53 may be configured to be provided separately from the print head 30.

The oscillation circuit 53 includes a frequency detection unit 535 that detects the oscillation frequency of the oscillation circuit 53.
Are connected in the vicinity. In this oscillation circuit 53, the impedance between the pair of electrodes 51a and 51b and the coil 531 is Z1, and the impedance of the capacitor 533 is Z2.
Assuming that the impedance of the capacitor 534 is Z3, the oscillation condition is expressed by the following equation (1). For this reason, the pair of electrodes 51a and 51b and the coil 531 are not in a resonance state but are represented by the formula (1
It is designed to be an L component that satisfies Further, the pair of electrodes 51a and 51b
Is the capacitance of C1, the inductance of the coil 531 is L1, the capacitance of the capacitor 533 is C2, and the capacitance of the capacitor 534 is C3. From this equation (1) and the phase condition,
Equation (2) can be derived. When this is solved for ω using the phase condition, the oscillation frequency f (natural frequency f) can be expressed by the following equation (3).

Here, the pair of electrodes 51a and 51b, the coil 531 and the capacitors 533 and 534 are sufficient when an ink droplet passes between the electrodes 51a and 51b during a predetermined measurement time as described later. The values of C1 to C3 and L1 are set such that the oscillation frequency f changes.

  The frequency detection unit 535 and a control unit 60 described later correspond to an example of a detection unit.

<Configuration of control unit>
Next, the configuration of the control unit 60 will be described with reference to FIGS. This control unit 6
0 is a signal from the nozzle inspection device 50 and signals from various sensors,
Based on the signal from this sensor, the controller 60 controls the CR motor 22 and the print head 30.
(Piezoelectric element 33), PF motor 41 and the like are driven.

In order to control the above-described units, the control unit 60 includes a communication interface 61 and a CPU 6.
2, a RAM 63, a ROM 64, and a head driver 65.

Among these, the communication interface 61 is a circuit for performing communication with the computer PC. The CPU 62 reads various data and various programs and executes various processes according to the various programs.

The RAM 63 is a part that temporarily stores various data. The ROM 64 is
Various programs and various data are stored, and the storage is maintained even when the printer 10 is turned off. Examples of programs stored in the ROM 64 include the printer 10.
There are a print control program 64a that controls the operation of each of these parts, and reference waveform data 64b of a head drive signal to be described later.

In addition, the ROM 64 stores a micro vibration generation program for inspection 64c, a signal determination processing program 64d, and a maintenance execution program 64e.

The inspection fine vibration generation program 64c is a program for performing control for applying vibration for detecting the meniscus state to the piezoelectric element 33 (hereinafter, this vibration is referred to as inspection fine vibration). . Here, the vibration for printing is a vibration for pushing ink out of the nozzle 32a and causing the ink to fly toward the print medium P. The fine vibration for inspection for detecting the state of the meniscus is Is not intended to fly toward the print medium P. The fine vibration for inspection changes the amount of ink entering the nozzle 32a between the electrodes 51a and 51b by moving the meniscus up and down without ejecting the ink from the nozzle 32a, and the electrodes 51a and 51b. The purpose of this is to cause a change in capacitance between the two.

For this reason, when a fine vibration for inspection is applied, the amount of deformation of the piezoelectric element 33 is smaller than when printing is performed, and as a result, the variation amount of the meniscus is also smaller than that during printing.

In the present embodiment, the piezoelectric element 33 is based on the inspection fine vibration generation program 64c.
Is vibrated so as to be a fine vibration for inspection, a change in capacitance is caused between the electrode 51a and the electrode 51b, and the change in capacitance is caused by a frequency detector 535 and / or a signal described later. The amplitude and period of the microvibration for inspection are set so as to be detected as a significant difference by the determination processing program 64d and the like.

The signal determination processing program 64d is a program for determining the meniscus state based on the detection signal output from the frequency detection unit 535 and input to the control unit 60. The meniscus is in the state of the electrode 51 even if a fine vibration for inspection is applied.
The meniscus is not between the electrodes 51a and 51b when a slight vibration for inspection is applied, whether it is in the state above the electrodes 51a and 51b (the piezoelectric element 33 side) without reaching between the electrodes 51a and 51b. There is at least a state of normal vibration. And the signal determination processing program 6
4d determines in which state the meniscus is.

In other words, the signal determination processing program 64d detects the detection signal obtained from the pair of electrodes 51a and 51b when the meniscus is expected to exist at a normal position and the pair when the meniscus is expected not to exist at a normal position. The state of the meniscus is determined via the frequency detection unit 535 from the detection signals obtained from the electrodes 51a and 51b.

The maintenance execution program 64e determines whether or not to perform maintenance based on the determination result determined by the signal determination processing program 64d.

The maintenance execution program 64e may determine which level of maintenance is to be executed based on the determination result. For example, the determination result includes the electrode 5
Information regarding the amplitude change amount of the detection signal obtained from 1a and 51b is included, and a state in which information relating to the amplitude change amount and a table in which the maintenance level is associated with the amplitude change amount in advance is provided. . The maintenance execution program 64e
The maintenance level associated with the information related to the amount of change in amplitude may be calculated from the above-described table, and the corresponding level of maintenance may be executed.

Further, the head driver 65 supplies power for driving the print head 30 (piezoelectric element 33) to the print head 30 (piezoelectric element 33) based on a command from the CPU 62.

<Detection of missing nozzles>
In the printer 10 having the above configuration, an operation when detecting missing nozzles will be described below. The nozzle missing means that the piezoelectric element 33 is used to eject ink.
In this state, the ink is not ejected from the nozzle 32a even though is driven. Further, whether or not the nozzle is missing corresponds to whether or not ink can be ejected from the nozzle 32a.

When the detection of nozzle omission is instructed during the operation of the printer 10 according to a predetermined sequence or a user's designation, the CPU 62 operates the CR motor 22 to drive the carriage 2.
1 is moved to a part such as a home position that is out of the printing area. Then CP
The above-described inspection fine vibration generation program 64c is read into U62, and the CPU 62 applies the inspection fine vibration to the piezoelectric element 33 corresponding to the specific nozzle 32a based on the inspection fine vibration generation program 64c. A command to that effect is output.

Then, this command is output to the head driver 65, and the head driver 65 applies power for applying a fine vibration for inspection to the piezoelectric element 33 corresponding to the specific nozzle 32a. As a result, the piezoelectric element 33 vibrates with an amplitude that is a fine vibration for inspection, and the vibration (fine vibration for inspection) is applied to the pressure generation chamber 315 and the ink existing in the nozzle 32a.

Here, as described above, the fine vibration for inspection is not intended to eject the ink toward the print medium P, and does not eject the ink from the nozzle 32a and enters the meniscus in the nozzle 32a. This is a vibration for facilitating detection by the frequency detector 535 or the like. That is, when a fine vibration for inspection is applied, as shown in FIG.
The state where ink is filled between the electrode 51b and the state where almost no ink exists between the electrode 51a and the electrode 51b is realized by moving the meniscus up and down.

In FIG. 8A, the average height of the meniscus (or the highest position of the meniscus or the lowest position of the meniscus) is located below or near the lower end of the lower end and lower end of the electrode 51a. It is in a state. 8B, the average height of the meniscus (or the lowest position of the meniscus or the highest position of the meniscus) is positioned above or near the upper end and upper end of the electrode 51a. It is in a state. However, when the fine vibration for inspection is applied, the liquid level is not limited to that shown in FIG. For example, as shown in FIG. 9, by applying a slight vibration for inspection to the ink, the average height of the meniscus (or the highest position of the meniscus or the lowest position of the meniscus) is set between the upper end and the lower end of the electrodes 51a and 51b. It may be in a state existing in the middle part (midway part).

As described above, when the fine vibration for inspection is applied to the ink and the meniscus is moved up and down without ejecting the ink from the nozzle 32a, the electrodes 51a and 5 are moved along with the change in the height position of the meniscus.
The capacitance between 1b changes. That is, the capacitance of the capacitor formed by the electrodes 51a and 51b changes.

Here, in the state before applying the fine vibration for inspection, the oscillation circuit 53 oscillates at a predetermined frequency f determined by the components of the oscillation circuit 53. Here, assuming that the meniscus is at a height position as shown in FIG. 8B in the stage before applying the fine vibration for inspection, the frequency detector 535 includes the electrodes 51a and 51b through the electrodes 51a and 51b. A detection signal as shown in FIG.

After the detection result shown in FIG. 10A is obtained, a fine vibration for inspection is applied to the ink, and when the ink is vibrated, the meniscus descends and the nozzle 32a is filled with the ink. As a result, the capacitance C1 of the capacitor constituted by the electrodes 51a and 51b changes. Then, the above-mentioned frequency f changes with change of electrostatic capacity C1 from above-mentioned formula (3). More specifically, when the nozzle 32a is not filled with ink, its relative dielectric constant is about 1. However, when the ink is filled in the nozzle 32a, the relative permittivity of the ink is larger than that of air, so that the electrodes 51a and 51 are in accordance with the relative permittivity of the ink.
The capacitance C1 of the capacitor constituted by b is also a large value. Therefore, the frequency f derived from the expression (3) is smaller than that in a state where the ink is not filled in the nozzles 32a.
Therefore, as shown in FIG. 10B, in the detection signal input to the frequency detection unit 535, the frequency f is small (the period is large).

In the frequency detection unit 535, the detection signals input from the electrodes 51a and 51b are analog signals. However, the frequency detection unit 535 binarizes the signals after A / D conversion within a predetermined measurement time. The count value is counted and the count value is output to the control unit 60. However, the above binarized signal may be counted by the control unit 60.

Here, in the control unit 60, the signal determination processing program 64d is read into the CPU 62, and the CPU 62 determines the meniscus state from the obtained count value based on the signal determination processing program 64d. In this determination process, for example, the frequency of the inspection fine vibration given by driving the piezoelectric element 33 via the head driver 65 is much larger than the natural frequency f in the oscillation circuit 53. When the meniscus is normal, a count value equivalent to that when the meniscus is present at a position between the upper end and the lower end of the electrode 51a is obtained. However, when the frequency of the above-described fine vibration for inspection is not so large or smaller than the natural frequency f, the obtained count value is obtained when the meniscus is positioned on the upper end side of the vibration. It fluctuates between the count value and the count value when the meniscus position is located on the lower end side of the vibration.

In any case, the CPU 62 determines the meniscus state based on the count value before applying the inspection fine vibration and the count value after applying the inspection fine vibration. In addition, as a determination result in the determination of the state of the meniscus, for example, after giving a fine vibration for inspection,
A case where it is determined that the meniscus is located at the position shown in FIG. 8A and is normal, and FIG.
) At least in the case where the meniscus is determined to be abnormal. In the case of applying the minute vibration for inspection, the meniscus has the height position shown in FIG.
Although it may be varied between the height positions shown in (B), for example, the height position shown in FIG. Further, the meniscus may slightly vibrate so that an intermediate height position between the height position shown in FIG. 8A and the height position shown in FIG. 8B becomes the average liquid level.

As described above, detection of missing nozzles for a specific nozzle 32a is performed. Thereafter, the detection of missing nozzles similar to that described above is sequentially executed for the other nozzles 32a.

In addition, after detecting missing nozzles for all the nozzles 32a and obtaining the meniscus determination result, the control unit 60 stores the maintenance execution program 64 in the CPU 62.
e is read, and the CPU 62 determines whether or not to perform maintenance, and if maintenance is determined to be performed, determines which maintenance is performed. The maintenance executed based on the maintenance execution program 64e includes, for example, flushing, pump suction executed after a cap (not shown) is brought into close contact with the nozzle plate 32, and the like.

<Effect in the first embodiment>
According to the printer 10 having the above-described configuration, when the ink supplied to the nozzle 32a is vibrated by the piezoelectric element 33, the meniscus vibrates. Then, the nozzle 32
The capacitance C1 of the electrodes 51a and 51b facing each other across a changes. Thereby, in the frequency detection part 535, based on the detection signal obtained from a pair of electrode 51a, 51b, the change of the electrostatic capacitance C1 can be detected and it is detected whether the nozzle omission has occurred. It becomes possible.

In the present embodiment, the pair of electrodes 51 a and 51 b are provided inside the nozzle plate 32. For this reason, the pair of electrodes 51 a and 51 b are provided integrally with the nozzle plate 32, and space saving of the printer 10 can be achieved. That is, in the conventional configuration, since the nozzle detection device is installed on one end side of the platen, space is required for the installation. On the other hand, in the configuration of the present embodiment, the electrode 51a
, 51 b are provided inside the nozzle plate 32. Therefore, a pair of electrodes 51a,
51b is integrated with the nozzle plate 32, so that no extra space is required as in the case where the nozzle detection device is provided separately, and the printer 10 can be miniaturized.

In addition, since the pair of electrodes 51a and 51b are provided inside the nozzle plate 32, whether or not the detection signal obtained from the electrodes 51a and 51b fluctuates with the vibration applied to the ink by the piezoelectric element 33. It is possible to detect whether or not ink can be ejected from the nozzles 32a. Therefore, even if ink is not actually ejected from the nozzle 32a, it is possible to detect whether or not the nozzle is missing by vibrating the ink inside the nozzle 32a. Thereby, it is possible to prevent the ink from being ejected wastefully in detecting the missing nozzle.

Further, in the present embodiment, the frequency detection unit 535 has the nozzle missing based on the detection signal corresponding to the change in the capacitance C1 when the ink passes between the pair of electrodes 51a and 51b. Whether or not is detected. For this reason, it is possible to reliably detect whether nozzle missing has occurred. That is, in a state where ink is filled between the electrode 51a and the electrode 51b and a state where almost no ink exists between the electrode 51a and the electrode 51b,
Since the change in the capacitance C1 appears as a significant difference, based on the change in the capacitance C1, it is possible to reliably detect whether or not nozzle missing has occurred.

Further, in the present embodiment, the detection of missing nozzles is detected when ink is not ejected from the print head 30 toward the print medium P. For this reason, it is possible to more reliably detect missing nozzles without affecting printing.

Further, in the present embodiment, the detection of nozzle omission is expected when the meniscus is expected to be present at a normal position and the detection signal obtained from the pair of electrodes 51a and 51b and the meniscus is not present at a normal position. In this case, the meniscus state is detected based on the detection signals obtained from the pair of electrodes 51a and 51b, and the maintenance operation is determined by the maintenance execution program 64e based on the detection of the meniscus state. .

Therefore, it is possible to execute an appropriate maintenance operation based on the detection of the meniscus state, and it is possible to execute not only the detection of nozzle missing but also the recovery of nozzle missing.

Further, in the present embodiment, the nozzle inspection device 50 includes an oscillation circuit 53 whose natural frequency f changes depending on whether ink is present in the nozzle 32a. Therefore, it is possible to easily determine the meniscus state by detecting a change in the natural frequency f.

(Second Embodiment)
Hereinafter, a printer 10 and a liquid ejecting method as a liquid ejecting apparatus according to a second embodiment of the invention will be described with reference to FIGS. 11 and 12. In the present embodiment, the description of the same configuration as that described in the first embodiment is omitted and the same reference numerals are used.

In the present embodiment, as shown in FIG. 11, the configuration of the electrodes is different. That is, in the above-described first embodiment, as shown in FIG. 4 and the like, a configuration in which one electrode 51a exists for each nozzle row 32b is employed. However, the present embodiment is different in that an electrode 511a exists in one nozzle 32a.
That is, the electrode 51 is provided on each nozzle 32a separately from the other nozzles 32a.
1a and the electrode 511b are facing each other, and are in a state in which a separate and independent capacitance can be obtained.

Therefore, a large number of wiring patterns 521 exist in the nozzle plate 32. Note that the wiring pattern 521 may be shared with the nozzle 32a sufficiently separated from a certain nozzle 32a. Further, the pair of electrodes 511a and 511
Of b, the electrode 511b may be independent for each nozzle 32a similarly to the electrode 511a, but the same configuration as the electrode 51b shown in FIG. 4 may be adopted. That is, the electrode 511b
May be shared by all the nozzles 32a.

Further, as shown in FIG. 12, in the present embodiment, the frequency detector 535 includes an ASIC (Appl.
ication Specific Integrated Circuit) 536. That is, in the present embodiment, the electrodes 511a and 51 facing each other across the individual nozzles 32a.
The capacitance C1 of the capacitor constituted by 1b can be different for each nozzle 32a. Thereby, in this embodiment, since the detection of nozzle omission can be performed simultaneously for all (or a plurality of) nozzles 32a, the detection signal processing is performed using a dedicated ASIC 536. Yes. The detection result processed by the ASIC 536 is output from the ASIC 536 so that the CPU 62 can process the detection result, for example. The ASIC 536 may be provided inside the control unit 60.

<Detection of missing nozzles>
In the printer 10 having the above configuration, an operation when detecting missing nozzles will be described below.

In the present embodiment, as described above, it is possible to simultaneously detect the nozzle omission in all (or a plurality of) nozzles 32a. Therefore, the first
It is possible to detect two types of missing nozzles, the pattern and the second pattern.

(1) About the first pattern for detecting missing nozzles The first pattern for detecting missing nozzles is a predetermined sequence or user designation during operation of the printer 10 as in the case of the first embodiment described above. When the detection of nozzle omission is instructed, the CPU 62 activates the CR motor 22 to move the carriage 21 to a location outside the printing area, such as the home position, and detects nozzle omission. It is.

Here, in the detection of missing nozzles in the first embodiment described above, after detecting missing nozzles for a specific nozzle 32a, detection of missing nozzles for other nozzles 32a is also sequentially executed. However, in the first pattern for detecting missing nozzles, it is possible to simultaneously detect the missing nozzles for all (or a plurality of) nozzles 32a. The details of the detection of missing nozzles are the same as those described in the first embodiment in which the detection of missing nozzles is sequentially executed for each nozzle 32a, except that all the nozzles 32a are simultaneously executed. It is the same.

(2) Second pattern for detecting missing nozzles Unlike the first pattern for detecting missing nozzles, the second pattern for detecting missing nozzles is to detect missing nozzles during printing. It is. In other words, in the present embodiment, it is possible to detect the missing nozzles in all (or a plurality of) nozzles 32a at the same time, so that the missing nozzles are detected even during printing or flushing. It is possible.

Here, when ink droplets are ejected from a certain nozzle 32a during printing or flushing, the amount of ink in the vicinity of the nozzle 32a is different before and after the ejection of the ink droplet. The capacitance C1 of the configured capacitor changes. That is, the frequency f described above changes before and after injection. Therefore, it is possible to detect whether or not nozzle missing has occurred based on the detection of the change in frequency f.

When no nozzle omission occurs, the nozzle 32a is filled with ink before ink is ejected from a certain nozzle 32a. In this state, when ink is ejected, the amount of ink in the nozzle 32a decreases. Therefore, in the state before jetting ink,
The frequency f is smaller than the state after injection. Therefore, it is possible to determine that the change in the frequency f before and after ink ejection is normal. In addition, when the nozzle is missing, the ink is not ejected from the nozzle 32a, and thus the frequency f may not change before and after the ejection of the ink. In addition, when the nozzle is missing, the ink may not be ejected from the nozzle 32a, but the ink may move up and down in the nozzle 32a. Even in such a case, the frequency f when the ink is abnormal before ejecting the ink should be larger than that before the ink is ejected when the nozzle is not missing. For this reason, in addition to the change in the frequency f, the value of the frequency f before ink ejection is also detected, so that it is possible to detect nozzle missing more satisfactorily.

In the second pattern, while printing or flushing is being performed,
The inspection vibration as described in the first embodiment is applied to the nozzle 32a that is not ejecting ink, and the nozzle missing is detected only for the nozzle 32a to which the inspection vibration is applied. You may make it do.

<Effect in 2nd Embodiment>
According to the printer 10 having the above configuration, when ink is ejected from the nozzle 32a, detection signals output from the pair of electrodes 511a and 511b facing each other with the nozzle 32a interposed therebetween are changed. Thereby, in the frequency detection part 535, a pair of electrodes 511a,
Based on the detection signal obtained from 511b, it is possible to detect whether nozzle missing has occurred. That is, also in the present embodiment, it is possible to produce the same effect as in the first embodiment described above.

Here, also in the printer 10 according to the present embodiment, the pair of electrodes 511a and 511b are connected to the nozzle plate 32 as in the printer 10 according to the first embodiment.
Is provided inside. As a result, the printer 10 can save space. That is, in the conventional configuration, since the nozzle detection device is installed on one end side of the platen, space is required for the installation, but in this embodiment, the electrode 51 is used.
Since 1a and 511b are provided inside the nozzle plate 32, a pair of electrodes 511a
, 511b are integrated with the nozzle plate 32, so that no extra space is required as in the case where the nozzle detection device is provided separately. Therefore, the printer
10 can be miniaturized.

In the present embodiment, one electrode 511a is provided for each nozzle 32a.
For this reason, it is possible to simultaneously detect nozzle omission in all (or a plurality of) nozzles 32a. Thereby, it is possible to detect the missing nozzle in the nozzle 32a in a short time. Further, since it is possible to detect the missing nozzles in all (or a plurality of) nozzles 32a at the same time, even when ink is ejected toward the print medium P,
This detection can be performed.

Further, in the first pattern in the present embodiment, it is possible to detect missing nozzles by an operation different from printing. Therefore, if it is detected that there is a missing nozzle in the detection, a maintenance operation can be executed. Accordingly, it is possible to prevent the print medium P from being consumed unnecessarily by performing printing while nozzle missing is present.

Further, in the second pattern in the present embodiment, it is possible to detect nozzle missing during printing. This eliminates the need for additional time for detection and improves the throughput in printing.

In the second pattern, when detecting missing nozzles in the nozzles 32a from which ink is ejected, such as during printing or flushing, the piezoelectric element 33 is vibrated based on a printing signal, and a separate operation is performed. It is possible not to give a fine vibration for inspection. Thereby, it is possible to simply detect missing nozzles. However, even in the case of detecting the missing nozzle in the nozzle 32a from which the ink is ejected, such as during printing or flushing, in the second pattern, the ink is superimposed on the ink together with the vibration for printing. A fine vibration for inspection may be applied. In this case, it is possible to improve the detection accuracy even when the ink is being ejected during printing or flushing by applying the minute vibration for inspection to the ink.

Further, in the second pattern, the inspection fine vibration as described in the first embodiment is applied to the nozzle 32a that is not ejecting ink while printing or flushing is being performed, and ink is ejected. When detecting missing nozzles only for the nozzles 33a that have not been printed, the accuracy of detecting missing nozzles is good even during printing or flushing.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can be variously modified. This will be described below.

In each of the above-described embodiments, the configuration in which the pair of electrodes 51a and 51b and the nozzle inspection device 50 are provided in the printer 10 in which the print head 30 can move along the main scanning direction is described. However, the pair of electrodes 51a and 51b and the nozzle inspection apparatus 50 may be configured to be provided in a line head having a length in the main scanning direction without moving the print head in the main scanning direction. Even in the case of such a configuration, it is possible to satisfactorily detect whether or not nozzle missing has occurred. In addition, it is possible to save the space of the printer, and it is possible to reduce the size of the printer.

Further, in each of the above-described embodiments, it is detected whether nozzle missing has occurred based on a change in the capacitance C1 between the pair of electrodes 51a and 51b. However,
As described above, not only when the capacitance C1 changes but also by detecting a change in resistance between the pair of electrodes, it may be detected whether or not nozzle omission has occurred. In this case, the pair of electrodes is preferably configured to be exposed to the nozzle 32a.

In such a configuration, when ink is present between the pair of electrodes, the electrical resistance is changed as compared with the case where ink is not present. It is also possible to detect whether or not nozzle missing has occurred based on such a change in electrical resistance.

Further, in the printer in each of the above-described embodiments, a change in dielectric constant with respect to the temperature of ink supplied to the nozzles is obtained in advance, and this change in temperature is added to the detection result such as a count value based on the detection signal. The presence or absence of missing nozzles may be detected. In this case, it is possible to detect the presence or absence of missing nozzles with higher accuracy even if the ink temperature changes. In this case, it is desirable that the printer is equipped with a temperature sensor. In addition, it is more preferable that the temperature sensor can detect the temperature of ink existing in the pressure generation chamber, for example.

Further, in each of the above-described embodiments, the case where the piezoelectric element 33 is used as the vibration applying unit is described, and the piezoelectric element 33 is operated to apply a fine vibration for inspection to the ink. It has become. However, the vibration applying means is not limited to the piezoelectric element 33. For example, the vibration applying means includes a vibration applying means (for example, an ultrasonic vibrator) separate from the piezoelectric element 33, and the operation of the separate vibration applying means. Therefore, the ink may be configured to vibrate. Even with this configuration, it is possible to detect nozzle omission based on the state of the meniscus.

Further, in each of the above-described embodiments, a pair of electrodes 51 a is provided inside the nozzle plate 32.
, 51b may be embedded, and a configuration in which the frequency detection unit is embedded in the nozzle plate 32 may be employed. Further, a configuration in which the entire oscillation circuit 53 is embedded in the nozzle plate 32 may be employed. In the case of such a configuration, the wiring pattern 52 provided inside the nozzle plate 32 can be shortened. Of course, the configuration in which the entire frequency detection unit or the oscillation circuit is embedded in the nozzle plate 32 can be manufactured using a semiconductor manufacturing technique.

Further, in each of the above-described embodiments, a configuration in which a pair of electrodes exist with a nozzle interposed therebetween is shown, but it is sufficient that a pair of electrodes exist with a nozzle interposed therebetween. It is not limited. For example, there is one or more electrodes on one side across the nozzle, and there is a pair of electrodes even if one or more electrodes are on the other side across the nozzle. Since there is no change, such a configuration may be adopted.

Further, in the first embodiment described above, the timing for detecting missing nozzles may be when the printer 10 is turned on or when no printing is performed for a predetermined time.

In the second embodiment described above, nozzle missing may be always detected during printing or flushing, but nozzle missing may be detected only immediately after printing starts or immediately after flushing. Further, it is possible to detect nozzle missing intermittently instead of always detecting nozzle missing during printing or flushing. Here, there are timings for detecting intermittent nozzle missing every predetermined time measured by a timer, and nozzle missing once in either the forward, backward or reciprocal movement of the carriage. Detection may be performed, or may be performed when printing on one print medium P is completed and printing on the next print medium P is started.
Further, when the print data is converted into the drive signal of the piezoelectric element 33, the nozzle omission may be detected for each predetermined data amount of the drive signal.

In the above-described embodiment, the control unit 60 may be realized by software, or may be realized by a circuit.

Further, the liquid ejecting apparatus according to the above-described embodiment may include both the functions of the printer 10 and the computer PC.

In addition, the printer 10 may be a multifunction device including a scanner device, a fax device, a copy device, and the like other than the printing function as the printer of the present invention.

In addition, the concept of the printer 10 in the above-described embodiment includes a liquid other than ink (
It may include a fluid ejecting apparatus that ejects or ejects the liquid itself, a liquid material in which particles of the functional material are dispersed or mixed in the liquid, and a fluid material such as a gel). it can. As such, a liquid containing a material such as an electrode material or a color material (pixel material) used for manufacturing a liquid crystal display, an EL (electroluminescence) display, and a surface emitting display is dispersed or dissolved. There are a liquid ejecting apparatus, a fluid ejecting apparatus that ejects a bio-organic matter used for biochip manufacturing, a fluid ejecting apparatus that ejects a liquid that is used as a precision pipette and serves as a sample, and the like.

Further, the concept of the printer 10 of the present invention includes a micro hemispherical lens (optical lens) used in a fluid ejecting apparatus, an optical communication element, and the like that ejects lubricating oil pinpoint to a precision machine such as a watch or a camera. A fluid ejecting apparatus that ejects a transparent resin liquid such as an ultraviolet curable resin onto a substrate to form a substrate, a fluid ejecting apparatus that ejects an etchant such as an acid or an alkali to etch the substrate, etc., a gel (for example, a physical gel ) And the like.

DESCRIPTION OF SYMBOLS 10 ... Printer (corresponding to an example of a liquid ejecting apparatus), 20 ... Carriage mechanism, 21 ... Carriage, 22 ... CR motor, 30 ... Print head (corresponding to an example of a liquid ejecting head), 31
... head body, 32 ... nozzle plate, 32a ... nozzle, 32b ... nozzle row, 33 ... piezoelectric element (corresponding to an example of vibration applying means), 40 ... paper transport mechanism, 41 ... PF motor, 51a
, 51b ... electrodes, 52 ... wiring pattern, 53 ... oscillation circuit, 60 ... control unit, 61 ... communication interface, 62 ... CPU, 63 ... RAM, 64 ... ROM, 64a ... print control program, 64b ... reference waveform data, 64c ... Inspection fine vibration generation program, 64d ... Signal determination processing program, 64e ... Maintenance execution program, 65 ... Head driver, 311
... flow path forming substrate, 315 ... pressure generating chamber, 316 ... ink supply path, 317 ... reservoir, 5
11a, 511b ... electrodes, 521 ... wiring pattern, 531 ... coil, 532 ... buffer,
533, 534 ... Condenser, 535 ... Frequency detector, PC ... Computer, P ... Print medium (corresponding to an example of an injection target)

Claims (7)

A liquid ejecting head including a nozzle plate in which a plurality of nozzles for ejecting liquid toward the outside are formed;
A pair of electrodes provided at least partially inside the nozzle plate;
Detecting means that is electrically connected to the electrode and detects whether or not the liquid can be ejected from the nozzle based on electric power obtained from the electrode according to the state of the meniscus of the liquid;
Comprising
One electrode of the pair of electrodes is provided for each nozzle,
The other electrode of the pair of electrodes is provided so as to face the one electrode across the nozzle and is a common electrode for the plurality of nozzles.
A liquid ejecting apparatus. The liquid ejecting apparatus according to claim 1,
The detection means detects whether or not the liquid can be ejected from the nozzle based on a detection value corresponding to a change in capacitance when the liquid passes between the pair of electrodes.
A liquid ejecting apparatus. The liquid ejecting apparatus according to claim 1, wherein
The liquid ejecting apparatus according to claim 1, wherein the detecting unit performs detection when the liquid is ejected from the liquid ejecting head toward an ejecting target. The liquid ejecting apparatus according to any one of claims 1 to 3,
The detection means includes a detection signal based on electric power obtained from the pair of electrodes when the meniscus is expected to be present at a normal position, and the pair when the meniscus is not expected to be present at a normal position. A maintenance signal that is an operation of detecting the state of the meniscus based on at least one of the detection signals based on the power obtained from the electrodes and discharging the liquid to the outside based on the detection of the state of the meniscus. Select one of the
A liquid ejecting apparatus. The liquid ejecting apparatus according to any one of claims 1 to 4,
The detection means includes an oscillation circuit capable of oscillating at a natural frequency that varies depending on the presence or absence of the liquid.
A liquid ejecting apparatus. A liquid ejecting head including a nozzle plate in which a plurality of nozzles for ejecting liquid toward the outside is formed,
A pair of electrodes that are provided at least in part inside the nozzle plate and that output electric power for detecting whether or not the liquid can be ejected from the nozzle according to the state of the meniscus of the liquid; ,
Comprising
One electrode of the pair of electrodes is provided for each nozzle,
The other electrode of the pair of electrodes is provided so as to face the one electrode across the nozzle and is a common electrode for the plurality of nozzles.
A liquid jet head characterized by that. In a liquid ejecting head having a nozzle plate in which a plurality of nozzles for ejecting liquid toward the outside are formed, a nozzle missing detection method for detecting whether or not the liquid can be ejected from the nozzle,
The liquid ejecting head includes a pair of electrodes provided at least partially inside the nozzle plate, and one electrode of the pair of electrodes is provided for each nozzle, and the pair of electrodes The other electrode of the electrodes is provided so as to face the one electrode across the nozzle and is a common electrode for the plurality of nozzles,
A detection step of detecting whether or not the liquid can be ejected from the nozzle based on the electric power obtained from the electrode according to the state of the meniscus of the liquid;
A nozzle omission detection method comprising:

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