JP6384157B2 - Liquid ejecting apparatus and control method thereof - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus such as an ink jet printer and a control method thereof, and more particularly to a liquid ejecting apparatus that ejects a liquid containing a component that may cause sedimentation, and a control method thereof. is there.

  For example, a liquid ejecting apparatus is an apparatus that includes a liquid ejecting head capable of ejecting liquid from a nozzle and ejects various liquids from the liquid ejecting head. As a representative example of this liquid ejecting apparatus, for example, an ink jet recording head (hereinafter simply referred to as a recording head) as a liquid ejecting head is provided, and liquid ink is supplied from a nozzle of the recording head to a recording medium such as recording paper. An image recording apparatus such as an ink jet printer (hereinafter simply referred to as a printer) that records an image, text, or the like by jetting and landing on (landing target) can be given.

  In recent printers, in addition to general color inks including black (K), cyan (C), magenta (M), and yellow (Y) colorants, which are the basic colors for character and image formation. In some cases, special ink is used so that it can be used for various purposes. For example, the printer disclosed in Patent Document 1 is configured to perform recording using a white ink containing a white pigment such as titanium oxide or a silver ink containing a glossy metal pigment such as an aluminum foil. The specific gravity of the color material of these white ink and silver ink is larger than the specific gravity of the color material of general color ink. For this reason, in the case of white ink or silver ink, the color material tends to settle with time. Moreover, sedimentation of the pigment occurs even with a normal pigment ink, although the degree is different. When the color material (pigment) settles, there is a possibility that the nozzles are clogged and the ink is not ejected normally. In order to suppress such problems, in this type of printer, ink is ejected from the nozzles by applying a micro-vibration pulse to an actuator (for example, a piezoelectric vibrator or a heating element) during a period when ink is not ejected. The ink and the meniscus in the pressure chamber are vibrated slightly to the extent that they are not ejected. In other words, the ink in the pressure chamber and the ink in the vicinity of the nozzle are agitated by this fine vibration operation.

JP 2002-351322 A

As described above, in a printer that employs the ink containing a component that is relatively easy to settle, it is desired to suppress sedimentation by performing as many micro-vibration operations as possible. However, there is a problem that if the fine vibration operation is continued, the ink viscosity increases. That is, since the meniscus in the nozzle is exposed to the atmosphere, the ink in the vicinity of the nozzle tends to thicken. As the ink thickened by the fine vibration operation is diffused in the pressure chamber, the viscosity gradually increases throughout the ink in the pressure chamber.
Even when the fine vibration operation is performed with the nozzle surface of the print head sealed with a cap or the like during a pause period in which the recording operation is not performed, the increase in ink is less than that of the former fine vibration operation. Depending on the elapsed time, ejection failure due to thickening (no ink is ejected from the nozzle, or even if ink is ejected from the nozzle, its weight, flight speed, etc. may change significantly from the target value) ) May occur.

  Such a problem occurs not only in the above-described printer but also in other liquid ejecting apparatuses configured to eject a liquid containing a component such as a pigment that may cause sedimentation.

  The present invention has been made in view of such circumstances, and an object thereof is to effectively vibrate while suppressing thickening of the liquid in a configuration in which the liquid containing a component that may cause sedimentation is ejected. An object of the present invention is to provide a liquid ejecting apparatus capable of suppressing liquid ejection failure by executing an operation, and a control method therefor.

The present invention has been proposed to achieve the above object, and a liquid ejecting head that ejects a liquid containing a pigment from a nozzle by driving an actuator;
Drive signal generating means for generating a fine vibration drive signal including a fine vibration waveform for driving the actuator to vibrate the liquid in the nozzle;
Control means for controlling a liquid ejecting operation by the liquid ejecting head,
The micro-vibration drive signal includes a first signal unit that generates a plurality of micro-vibration waveforms, and a second signal unit that maintains a constant potential,
A first mode in which a duration time of the second signal portion is set to a first time longer than a duration time of the first signal portion; and a duration time of the second signal portion is the first time A second mode set to a second time longer than the time can be selected;
The control means monitors the elapsed time of the minute vibration operation in the second mode, and when it is determined that the elapsed time has reached a predetermined upper limit value, stops the minute vibration operation in the second mode. It is characterized by.

  According to the present invention, the micro-vibration driving signal includes the first signal unit in which a plurality of micro-vibration waveforms are generated and the second signal unit in which the potential is kept constant. Thus, every time the micro-vibration operation is performed, the micro-vibration operation is stopped for a certain time by the second signal unit. Accordingly, it is possible to stir the liquid while suppressing the thickening of the liquid as compared with the configuration in which the fine vibration operation is continuously performed without being stopped halfway. This makes it possible to reduce the occurrence of ejection failure due to sedimentation of the pigment, which is a liquid-containing component, in a configuration using a liquid containing a component that has a relatively heavy specific gravity and is likely to settle. Further, the interval (so-called intermittent ability) that can be left without performing maintenance such as ejection of liquid from the nozzle and suction cleaning can be extended. Therefore, it is possible to reduce the frequency of performing the suction cleaning, and to suppress the consumption of the liquid. Furthermore, since the actuator is not continuously driven, deterioration of the actuator is suppressed, and also contributes to power saving.

  The first mode in which the duration of the second signal unit is set to the first time longer than the duration of the first signal unit, and the duration of the second signal unit is the first time. A second mode that is set to a second time longer than the first mode, for example, at the time of startup when the power of the liquid ejecting apparatus is turned on, the fine vibration operation that enhances the stirring effect in the first mode is performed. By doing so, it is possible to more effectively diffuse the components that have settled when the power is turned off, and after the fine vibration operation in the first mode, the second mode is switched to ensure a longer stop time. By performing the above, it is possible to diffuse the liquid while further suppressing the thickening of the liquid and suppress the precipitation of the pigment. Therefore, even in a situation where the power supply is turned off for a longer period of time, it is possible to suppress liquid thickening and pigment settling and reduce ejection failure.

  Further, when the elapsed time of the fine vibration operation in the second mode reaches a predetermined upper limit value, the fine vibration operation is stopped, so that the fine vibration operation in the second mode is continued for a long time. The viscosity increase of the liquid due to this is suppressed. As a result, it is possible to reduce the occurrence of ejection failure due to the thickening of the liquid while ensuring the effect of suppressing the sedimentation of the pigment that is the liquid-containing component.

  Further, in the above configuration, the control unit discharges liquid from the nozzle separately from the liquid ejecting operation before executing the next liquid ejecting operation after stopping the fine vibration operation in the second mode. It is desirable to adopt a configuration that performs a maintenance operation.

  According to this configuration, the maintenance operation is performed before the transition to the next liquid ejecting operation, so that the liquid thickened during the fine vibration operation in the second mode is discharged from the nozzle by the maintenance operation. . As a result, the viscosity of the liquid in the liquid ejecting head can be recovered to a state suitable for the liquid ejecting operation, so that it is possible to suppress the occurrence of ejection failure in the liquid ejecting operation.

  Furthermore, in the above configuration, it is desirable that the upper limit value adopts a configuration determined according to the composition of the liquid.

  According to this configuration, the fine vibration operation in the second mode can be stopped at a more appropriate timing according to the composition of the liquid.

  The said structure WHEREIN: The structure which is a titanium dioxide can be employ | adopted for the pigment contained in the said liquid.

The present invention also provides a liquid ejecting head that ejects a liquid containing pigment from a nozzle by driving an actuator, and a drive that generates a micro vibration drive signal including a micro vibration waveform that drives the actuator to vibrate the liquid in the nozzle. A control method of a liquid ejecting apparatus, comprising: a signal generating means; and a control means for controlling a liquid ejecting operation by the liquid ejecting head,
The micro-vibration drive signal includes a first signal unit that generates a plurality of micro-vibration waveforms, and a second signal unit that maintains a constant potential,
A first mode in which a duration time of the second signal portion is set to a first time longer than a duration time of the first signal portion; and a duration time of the second signal portion is the first time A second mode set to a second time longer than the time can be selected;
When it is determined that the elapsed time of the fine vibration operation in the second mode has reached a predetermined upper limit, the fine vibration operation in the second mode is stopped.
Moreover, the liquid ejecting apparatus of the present invention proposed for achieving the above object may have the following configuration.
That is, a liquid ejecting head that ejects a liquid containing a pigment from a nozzle by driving an actuator;
Drive signal generating means for generating a fine vibration drive signal including a fine vibration waveform for driving the actuator to vibrate the liquid in the nozzle;
Control means for controlling a liquid ejecting operation by the liquid ejecting head,
The micro-vibration drive signal includes a first signal unit that generates a plurality of micro-vibration waveforms, and a second signal unit that maintains a constant potential,
A first mode in which a duration time of the second signal portion is set to a first time longer than a duration time of the first signal portion; and a duration time of the second signal portion is the first time A second mode set to a second time longer than the time can be selected;
The control means monitors the elapsed time of the fine vibration operation in the second mode, and when it is determined that the elapsed time has reached an upper limit value determined in advance according to the ease of thickening of the liquid, The micro-vibration operation in mode 2 is stopped.
According to the present invention, the micro-vibration driving signal includes the first signal unit in which a plurality of micro-vibration waveforms are generated and the second signal unit in which the potential is kept constant. Thus, every time the micro-vibration operation is performed, the micro-vibration operation is stopped for a certain time by the second signal unit. Accordingly, it is possible to stir the liquid while suppressing the thickening of the liquid as compared with the configuration in which the fine vibration operation is continuously performed without being stopped halfway. For this reason, it is possible to reduce the occurrence of ejection failure due to sedimentation of the pigment, which is a component contained in the liquid, in a configuration using a liquid containing a component that has a relatively heavy specific gravity and tends to settle. Further, the interval (so-called intermittent ability) that can be left without performing maintenance such as ejection of liquid from the nozzle and suction cleaning can be extended. Therefore, it is possible to reduce the frequency of performing the suction cleaning, and to suppress the consumption of the liquid. Furthermore, since the actuator is not continuously driven, deterioration of the actuator is suppressed, and also contributes to power saving. Then, the first mode in which the duration of the second signal unit is set to the first time longer than the duration of the first signal unit, and the duration of the second signal unit from the first time And a second mode set to a long second time, for example, at the time of startup when the power of the liquid ejecting apparatus is turned on, the first mode performs a fine vibration operation that enhances the stirring effect. Therefore, it is possible to more effectively diffuse the contained components that have settled when the power is turned off, and after the fine vibration operation in the first mode, the fine vibration operation that switches to the second mode and ensures a longer stop time is achieved. By carrying out, it is possible to diffuse the liquid and suppress sedimentation of the pigment while further suppressing the thickening of the liquid. Therefore, even in a situation where the power supply is turned off for a longer period of time, it is possible to suppress liquid thickening and pigment settling and reduce ejection failure. Further, when the elapsed time of the fine vibration operation in the second mode reaches an upper limit value determined in advance according to the ease of thickening of the liquid, the fine vibration operation is stopped at a more appropriate timing. As a result, the thickening of the liquid caused by continuing the fine vibration operation in the second mode for a long time is more effectively suppressed. As a result, it is possible to reduce the occurrence of ejection failure due to the thickening of the liquid while ensuring the effect of suppressing the sedimentation of the pigment that is the liquid-containing component.
Further, in the above configuration, the control unit discharges liquid from the nozzle separately from the liquid ejecting operation before executing the next liquid ejecting operation after stopping the fine vibration operation in the second mode. It is desirable to adopt a configuration that performs a maintenance operation.
According to this configuration, the maintenance operation is performed before the transition to the next liquid ejecting operation, so that the liquid thickened during the fine vibration operation in the second mode is discharged from the nozzle by the maintenance operation. . As a result, the viscosity of the liquid in the liquid ejecting head can be recovered to a state suitable for the liquid ejecting operation, so that it is possible to suppress the occurrence of ejection failure in the liquid ejecting operation.
The said structure WHEREIN: The structure which is a titanium dioxide can be employ | adopted for the pigment contained in the said liquid.
The present invention also provides a liquid ejecting head that ejects a liquid containing pigment from a nozzle by driving an actuator, and a drive that generates a micro vibration drive signal including a micro vibration waveform that drives the actuator to vibrate the liquid in the nozzle. A control method of a liquid ejecting apparatus, comprising: a signal generating means; and a control means for controlling a liquid ejecting operation by the liquid ejecting head,
The micro-vibration drive signal includes a first signal unit that generates a plurality of micro-vibration waveforms, and a second signal unit that maintains a constant potential,
A first mode in which a duration time of the second signal portion is set to a first time longer than a duration time of the first signal portion; and a duration time of the second signal portion is the first time A second mode set to a second time longer than the time can be selected;
When it is determined that the elapsed time of the fine vibration operation in the second mode has reached the upper limit value determined in advance according to the ease of thickening of the liquid, the fine vibration operation in the second mode is stopped. Features.

It is a perspective view explaining the structure of a textile printer. It is a top view explaining the structure of a textile printer. It is a sectional side view explaining the structure of a textile printing printer. FIG. 5 is a schematic diagram illustrating an ink supply path from an ink cartridge to a textile printing head. It is principal part sectional drawing explaining the internal structure of a textile printing head. It is a block diagram explaining the electrical structure of a textile printing printer. It is a wave form diagram explaining the structure of a micro vibration drive signal. It is a wave form diagram explaining the structure of a micro vibration drive pulse. It is a timing chart explaining operation of a textile printer. It is a wave form diagram explaining the modification of a fine vibration drive pulse. It is a front view explaining the internal structure of the printer in 2nd Embodiment. 6 is a flowchart for explaining processing of a printer during maintenance work.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. Further, in the following, as the liquid ejecting apparatus of the present invention, an ink jet printing apparatus capable of printing a printed image such as an image or a letter by ejecting ink onto a material to be printed (a kind of landing target) such as a T-shirt ( Hereinafter, a textile printer will be described as an example. “Printed material” means “fabric” to be printed, natural fibers such as cotton, silk and wool, chemical fibers such as nylon, or woven fabrics, knitted fabrics and non-woven fabrics of these fibers. Etc. are included.

FIG. 1 is a perspective view illustrating the basic configuration of the textile printer 1. FIG. 2 is a plan view of the textile printer 1, and FIG. 3 is a side sectional view of the textile printer 1. FIG. 4 is a schematic diagram for explaining an ink supply path from the ink cartridge 16 to the printing head 5. The textile printer 1 according to the present embodiment includes a tray attachment portion 8 (see FIG. 3) on which the set tray 3 is detachably attached, and the surface of the printing material T set on the set tray 3 on the tray attachment portion 8. An obstacle detector 4 that can detect a convex portion (obstacle), a printer controller 45 that controls the operation of each part, an operation button that receives an instruction operation from a user, a liquid crystal display unit that displays predetermined information, and the like And an operation panel unit 6 provided.
Note that the surface of the printing material T described in the present embodiment refers to the surface on which the liquid ejected from the nozzle lands.

  The textile printer 1 reciprocates between a textile head 5 (a type of liquid ejecting head) that ejects ink onto a material T to form a printed image G such as an image or text, and a carriage 17 on which the textile head 5 is mounted. A carriage scanning unit 10 (see FIG. 6) to be moved and a moving unit 9 to move the set tray 3 are provided. The set tray 3 is made of, for example, a rectangular flat plate member, and a set surface 3a for setting the printing material T is formed on the upper surface thereof. The set surface 3a is a portion that supports the second surface Tb of the printing material T, and the entire surface is formed flat so that the printing material T can be set in a flat state.

  The moving part 9 can reciprocate along the moving direction A at the center part of the support base 11 extending along the moving direction A from the front to the back (back side) of the apparatus main body 2 of the textile printer 1. And a support base 12 having a slider and a pillar having a predetermined height, and a drive mechanism having a timing belt 13 for driving the support base 12. The set tray 3 is detachably attached to the tray attaching portion 8 on the upper surface of the support base 12. Then, the moving unit 9 moves the set tray 3 between the set position S where the printing material T is attached and detached and the printing start position K between which the printing execution area 15 is sandwiched by the printing head 5. It is configured to move with. The obstacle detector 4 detects the obstacle on the surface of the material T to be printed when the set tray 3 is moved from the set position S to the printing start position K.

  The obstacle detector 4 includes a pair of light-emitting elements 4a and light-receiving elements provided on the left and right sides (head movement direction) of the front opening Op (see FIG. 1) of the apparatus main body 2 through which the set tray 3 can pass. 4b. The light emitting element 4a is made of, for example, a light emitting diode, and is directed toward the light receiving element 4b located on the opposite side across the front opening of the apparatus main body 2 with respect to the passing region of the printing material T set on the set tray 3. Light is irradiated so as to be orthogonal. The light receiving element 4b is composed of, for example, a photodiode, and outputs a detection signal corresponding to the light receiving state or the non-light receiving state to the printer controller 45. When the set tray 3 is moved from the set position S to the printing start position K, if there are obstacles such as wrinkles or other irregularities or foreign matter on the surface of the printing material T, the obstacles are emitted from the light emitting element 4a. If the received light is blocked, the light receiving element 4b does not receive the light, and the detection signal changes accordingly. Therefore, the printer controller 45 can detect an obstacle on the surface of the printing material T on the set tray 3 based on the change in the detection signal from the light receiving element 4 b of the obstacle detector 4.

  When the printer controller 45 determines that an obstacle has been detected on the surface of the printing material T based on the detection signal from the obstacle detector 4, the printer controller 45 does not execute the printing operation by the printing head 5, and sets the tray. 3 is controlled to return to the set position S and the fact that an obstacle has been detected on the surface of the printing material T is displayed on the liquid crystal display unit of the operation panel unit 6 to notify the user. In response to this, the user resets the printing material T set on the set tray 3 by extending the wrinkles or removing foreign matter. After the resetting is completed, when the set tray 3 is moved from the set position S to the printing start position K, the obstacle detector 4 performs obstacle detection again. If no obstacle is detected by the obstacle detector 4, the set tray 3 moves to the printing start position K, and the printing operation for the printing material T by the printing head 5 is started from the position.

  The printing head 5 is held by a carriage 17 inside the apparatus main body 2. The carriage 17 is configured to be movable in a scanning direction B (main scanning direction) that is a direction intersecting the moving direction A of the set tray 3 by the carriage scanning unit 10 (see FIG. 6). One end of the carriage 17 in the scanning direction B (the right end in FIG. 2) is a home position, and below this home position is the nozzle surface of the printing head 5 (the surface on the ink ejection side of the nozzle plate 28). A capping mechanism 7 capable of sealing is provided. The capping mechanism 7 is composed of a cap member 7a made of a tray-like elastic material having an open upper surface side, and a pump (not shown) that makes negative pressure in the internal space of the cap member 7a in a state where the nozzle surface is sealed. . The capping mechanism 7 is configured to be movable by a moving mechanism (not shown), and includes a sealed state in which the cap member 7a seals the nozzle surface of the printing head 5, and a retracted state in which the cap member 7a is separated from the nozzle surface. Can be switched to. Specifically, when the printing head 5 is in a standby state in which the printing operation is not performed on the printing material T, or when the power of the printing printer 1 is turned off, the carriage 17 is positioned at the home position. The nozzle surface of the printing head 5 is capped by the capping mechanism 7. Thereby, the evaporation of the ink solvent from the nozzles 34 of the textile printing head 5 is suppressed. Further, during the flushing operation in which the printing head 5 forcibly discharges thickened ink or the like during the printing operation, the cap member 7a is ejected from the printing head 5 without capping the nozzle surface in the retracted state. It functions as an ink receiving portion that receives the discharged ink. Further, in the maintenance operation (suction cleaning operation, which is a kind of maintenance operation in the present invention) that is a process of removing the thickened ink and bubbles in the printing head 5 to recover the clogging of the nozzles, the capping state described above. Then, the pump is operated to make the internal space of the cap member 7a have a negative pressure, thereby forcibly discharging ink and bubbles from the nozzle into the cap member 7a. The waste ink discharged to the cap member 7a is discharged to a waste ink tank (not shown).

The printing head 5 introduces ink supplied from an ink cartridge 16 mounted on the front side of the apparatus main body 2 via the supply tube 14 and the like, and introduces the introduced ink to the first surface Ta of the printing material T. Textile printing is performed by ejecting the ink toward the surface and landing the ink. In this embodiment, a so-called serial type printing head 5 is employed that ejects ink onto the printing material T while reciprocating in the scanning direction B of the carriage 17.
As shown in FIG. 4, in the present embodiment, a sub tank 18 is provided between the ink cartridge 16 and the printing head 5. The sub tank 18 is configured such that ink from the ink cartridge 16 is supplied through the supply tube 14 and stores the ink. The sub tank 18 and the printing head 5 are connected by a pair of circulation tubes 19a and 19b. The first circulation tube 19a and the second circulation tube 19b communicate with each other via an ink flow path inside the printing head 5. Further, in the middle of the first circulation tube 19a, a circulation pump 50 (see FIG. 6) constituted by, for example, a gear pump is disposed. When the circulation pump 50 is operated, the ink is circulated between the sub tank 18 and the printing head 5 through the circulation tubes 19a and 19b as shown by white arrows in FIG. . This circulation operation is a kind of maintenance operation in the present invention, and is controlled by a CPU 47 described later.

FIG. 5 is a cross-sectional view of the main part for explaining the internal configuration of the printing head 5.
The textile printing head 5 in this embodiment includes a case 20, a vibrator unit 21 housed in the case 20, a flow path unit 22 joined to the bottom surface (tip surface) of the case 20, and the like. Yes. The case 20 is made of, for example, an epoxy resin, and a housing empty portion 23 for housing the vibrator unit 21 is formed therein. The vibrator unit 21 includes a piezoelectric element 24 that functions as a kind of actuator in the present invention, a fixing plate 25 to which the piezoelectric element 24 is joined, and a flexible cable 26 for supplying a drive signal and the like to the piezoelectric element 24. I have. The piezoelectric element 24 is a laminated type produced by cutting a piezoelectric plate in which piezoelectric layers and electrode layers are alternately laminated into a comb-like shape, and is so-called longitudinal vibration mode capable of expanding and contracting in a direction perpendicular to the lamination direction. This is a piezoelectric vibrator.

  The flow path unit 22 is configured by joining a nozzle plate 28 to one surface of the flow path forming substrate 27 and a diaphragm 29 to the other surface of the flow path forming substrate 27. The flow path unit 22 is provided with a reservoir 30 (common liquid chamber), an ink supply port 31, a pressure chamber 32, a nozzle communication port 33, and a nozzle 34. A series of ink flow paths from the ink supply port 31 to the nozzle 34 through the pressure chamber 32 and the nozzle communication port 33 is formed corresponding to each nozzle 34. As described above, the ink flow path is configured to allow ink to circulate between the sub tank 18 via the circulation tubes 19a and 19b.

  The nozzle plate 28 is a thin plate made of a metal such as stainless steel or a silicon single crystal substrate in which a plurality of nozzles 34 are formed in rows at a pitch corresponding to the dot formation density. The nozzle plate 28 is provided with a plurality of nozzle rows 34 (nozzle rows), and one nozzle row is composed of, for example, 180 nozzles 34. The printing head 5 in the present embodiment includes different colors of ink (a kind of liquid in the present invention), specifically cyan (C), magenta (M), yellow (Y), and black (K). In addition to the total of four colors of ink, a total of six colors of ink including white ink (W) and silver ink (S) are used. A total of six nozzle rows corresponding to these colors are formed on the nozzle plate 28.

  Here, the white ink is an ink containing a white pigment component, and is a kind of white liquid. For example, titanium dioxide can be suitably used as the white pigment. Silver ink is an ink containing a glossy pigment component and is a kind of glossy liquid. As the glossy pigment, for example, a powdery or pasty metal pigment made of a metal such as aluminum, or a pearl pigment made of titanium mica whose surface is coated with a metal oxide can be used. Note that “white” is a color that is visually recognized as white, and is not limited to an achromatic white color. For example, white that is slightly tinted, such as off-white or ivory white, is included. Means. The “glossy liquid” means a liquid containing a pigment that can visually recognize glossiness in a recorded image or the like by reflecting light.

  The diaphragm 29 has a double structure in which an elastic film 37 is laminated on the surface of the support plate 36. In the present embodiment, a stainless plate, which is a kind of metal plate, is used as the support plate 36, and the vibration plate 29 is configured by a composite plate material in which a resin film is laminated as an elastic film 37 on the surface of the support plate 36. The diaphragm 29 is provided with a diaphragm portion 38 that changes the volume of the pressure chamber 32. The diaphragm 29 is provided with a compliance portion 39 that seals a part of the reservoir 30.

  The diaphragm portion 38 is produced by partially removing the support plate 36 by etching or the like. That is, the diaphragm portion 38 includes an island portion 40 to which the front end surface of the piezoelectric element 24 is joined, and a thin elastic portion surrounding the island portion 40. The compliance part 39 is produced by removing the support plate 36 in the region facing the opening surface of the reservoir 30 by etching or the like in the same manner as the diaphragm part 38, and the pressure fluctuation of the liquid stored in the reservoir 30 is reduced. Functions as a damper to absorb.

  Since the tip surface of the piezoelectric element 24 is joined to the island portion 40, the volume of the pressure chamber 32 can be changed by expanding and contracting the piezoelectric element 24. A pressure fluctuation occurs in the ink in the pressure chamber 32 in accordance with the volume fluctuation. The textile printing head 5 ejects ink droplets from the nozzles 34 using this pressure fluctuation.

  FIG. 6 is a block diagram illustrating the electrical configuration of the textile printer 1. The external device 44 is an electronic device that handles images, such as a computer, a digital camera, or a mobile phone. The external device 44 is communicably connected to the textile printer 1, and in order to cause the textile printer 1 to print an image, text, etc. on the printing material T, print data corresponding to the image etc. is transmitted to the textile printer 1. To do.

  The textile printer 1 in this embodiment includes a tray moving unit 9, a carriage scanning unit 10, an obstacle detector 4, an operation panel unit 6, a textile printing head 5, a circulation pump 50, and a printer controller 45.

  The printer controller 45 is a kind of control means, and is a control unit that controls each part. The printer controller 45 includes an interface (I / F) unit 46, a CPU 47, a storage unit 48, and a drive signal generation unit 49. The interface unit 46 transmits and receives printer status data, such as sending print data and a print command from the external device 44 to the textile printer 1, and receiving the status information of the textile printer 1. The CPU 47 is an arithmetic processing unit for controlling the entire printer. The memory | storage part 48 is an element which memorize | stores the data used for the program and various control of CPU47, and contains ROM, RAM, and NVRAM (nonvolatile memory element). The CPU 47 controls each unit according to a program stored in the storage unit 48.

  The drive signal generation unit 49 functions as drive signal generation means in the present invention, and generates an analog voltage signal based on waveform data relating to the waveform of the drive signal. The drive signal generation unit 49 amplifies the voltage signal to generate a drive signal. The textile printer 1 in the present embodiment is used for a textile printing operation (a kind of liquid jetting operation in the present invention) in which a printing image G is printed by ejecting ink from the nozzles 34 of the textile printing head 5 onto the printing material T. In addition to the drive signal, a fine vibration drive signal vCOM (see FIG. 7) used for a fine vibration operation for stirring the ink in the pressure chamber 32 of the printing head 5 or the meniscus in the nozzle 34 in a standby state other than the printing operation is generated. Is configured to do.

FIG. 7 is a waveform diagram for explaining an example of the configuration of the micro-vibration drive signal vCOM.
The textile printer 1 according to the present invention is configured to be able to set three types of modes, and the drive signal generation unit 49 generates three types of micro-vibration drive signals vCOM corresponding to each mode. More specifically, the drive signal generation unit 49 includes a first fine vibration drive signal vCOM1 corresponding to the first mode, a second fine vibration drive signal vCOM2 corresponding to the second mode, and a third A third micro-vibration drive signal vCOM3 corresponding to the mode is generated.

In each micro-vibration drive signal vCOM, a micro-vibration drive pulse VP (a kind of micro-oscillation waveform in the present invention) that generates a pressure fluctuation in the ink in the pressure chamber 32 to the extent that ink is not ejected from the nozzle 34 is generated. .
FIG. 8 is a waveform diagram for explaining an example of the configuration of the micro-vibration driving pulse VP. The fine vibration drive pulse VP includes a first potential change unit p11 that changes the potential from the reference potential Eb to the fine vibration potential Eh to the plus side (first polarity side), and a potential maintenance that maintains the fine vibration potential Eh for a predetermined time. Part p12, and a second potential changing part p13 that changes the potential from the micro-vibration potential Eh to the negative side (second polarity side) and returns to the reference potential Eb.

  The drive voltage of the fine vibration drive pulse VP, that is, the potential difference Vd from the reference potential Eb to the fine vibration potential Eh is set to an optimum value for stirring the ink in the pressure chamber 32. The potential change rate per unit time of the first potential change unit p11 is set to a value that does not cause ink to be ejected from the nozzles 34. Similarly, the potential change rate of the second potential change portion p13 is also set to a value that does not cause ink to be ejected from the nozzles 34.

  When this fine vibration drive pulse VP is supplied to the piezoelectric element 24, first, the pressure chamber 32 expands to such an extent that the piezoelectric element 24 is contracted by the first potential change unit p11 and ink droplets are not ejected from the nozzle 34. The expanded state of the pressure chamber 32 is maintained for a predetermined time by the potential maintaining unit p12. Thereafter, when the second potential changing portion p13 is supplied, the piezoelectric element 24 expands and contracts to the original state (a state corresponding to the reference potential Eb), and the pressure chamber 32 returns to the reference volume. Due to this series of movements, pressure fluctuations are generated in the ink in the pressure chambers 32 so as not to be ejected from the nozzles 34, and the inks and meniscus in the pressure chambers 32 are vibrated by the pressure fluctuations. In other words, the ink in the pressure chamber 32 and the ink in the vicinity of the nozzle 34 are agitated by this fine vibration operation. The finely vibrating operation diffuses the thickened ink and the settled pigment component in the pressure chamber 32 and in the vicinity of the nozzle 34.

  The first micro-vibration drive signal vCOM1 includes the first signal unit CP1 in which a plurality of micro-vibration drive pulses VP are continuously generated at a constant interval, and the potential is not generated by the micro-vibration drive pulse VP. This is a drive signal generated alternately with the second signal portion CP2 which is kept constant at Eb. That is, the first micro-vibration drive signal vCOM1 is a drive that causes the micro-vibration operation to be stopped for the duration T2 by the second signal unit CP2 after the micro-vibration operation is performed for the duration T1 by the first signal unit CP1. Signal. In FIG. 7, the number of micro-vibration driving pulses VP generated by the first signal unit CP1 is schematically shown as three for convenience, but actually, more micro-vibration driving pulses VP are generated. The Here, the duration T1 of the first signal portion CP1 is set to a time that is sufficient to stir the settled pigment component and does not excessively increase the viscosity of the ink by the fine vibration operation. This duration T1 is determined according to the environment such as the type of ink and temperature. That is, in a configuration in which an ink containing a pigment component that is more likely to settle is handled, or in a situation where the temperature is low and the viscosity is higher, the duration T1 is set to a longer time, and the pigment component is less likely to settle than the former ink. In a configuration that handles ink that contains ink, or in a situation where the temperature is high and the viscosity is lower, the duration T1 is set to a shorter time. On the other hand, the duration T2 (or fine vibration stop time, corresponding to the first time in the present invention) of the second signal unit CP2 is set to a ratio of 1 to 100 with respect to the duration T1.

  The first mode in which the fine vibration operation is performed using the first fine vibration drive signal vCOM1 is at the start-up time when the power of the textile printer 1 is turned on, and the textile printing head 5 positioned at the home position. It is set in a state where the nozzle surface is capped by the capping mechanism 7. The execution time of the first mode is set to a value (specified execution time) according to the time from the last power-off to the next power-on within a range of up to 20 minutes from the start, for example. Is done. That is, the longer the time during which the power is off, the longer the specified execution time of the first mode is set. During the execution of the micro-vibration operation in the first mode, even when the printer controller 45 is instructed to perform the printing operation or other maintenance, other operations such as the printing operation until the specified execution time ends. Do not migrate to.

  Further, the second micro-vibration drive signal vCOM2 is a drive signal in which the first signal unit CP1 and the second signal unit CP2 are alternately generated, similarly to the first micro-vibration drive signal vCOM1. . The second micro-vibration drive signal vCOM2 is a drive signal for stopping the micro-vibration operation by the second signal unit CP2 only for the duration T4 after the micro-oscillation operation is performed by the first signal unit CP1 for the duration T3. It is. The duration T3 of the first signal portion CP1 in the second micro-vibration drive signal vCOM2 is set to such a time that the ink thickening does not proceed excessively by the micro-vibration operation. For example, the first micro-vibration drive is performed. It is set to the same value as the duration T1 of the first signal part CP1 in the signal vCOM1. On the other hand, the duration T4 (corresponding to the second time in the present invention) of the second signal portion CP2 in the second micro-vibration driving signal vCOM2 is, for example, a time having a ratio of 50 to 3600 with respect to the duration T3. Thus, it is set longer than the duration T2 of the second signal portion CP2 in the first micro-vibration drive signal vCOM1. The second mode in which the micro-vibration operation is performed using the second micro-vibration drive signal vCOM2 is a time other than when the first mode is executed at the time of power activation, and the nozzle surface of the printing head 5 positioned at the home position. Is set in a state (standby state) capped by the capping mechanism 7.

  The third micro-vibration drive signal vCOM3 is a drive signal that generates only the first signal unit CP1, unlike the first micro-vibration drive signal vCOM1 and the second micro-vibration drive signal vCOM2. In the third mode in which the micro-vibration operation is performed using the third micro-vibration driving signal vCOM3, until there is an instruction to execute the printing operation or other maintenance, and the printing operation can be executed. It is set in a state where the nozzle surface of the printing head 5 is opened from the capping state by the capping mechanism 7. The duration T5 of the first signal unit CP1 in the third micro-vibration drive signal vCOM3 varies depending on the time from when the execution instruction for the printing operation or the like is given until the printing operation or the like can be executed.

  FIG. 9 is a timing chart for explaining an example of the fine vibration operation of the textile printer 1. When the textile printer 1 is switched from the power-off state to the power-on state at time t1, the start-up operation is started. At this time, the piezoelectric element 24 corresponding to each nozzle of the printing head 5 is driven by the first fine vibration drive signal vCOM1 in the state where the first mode is set and the nozzle surface of the printing head 5 is capped. Vibration operation is executed. As described above, in the fine vibration operation in the first mode, the printing operation or the like is performed until the set execution time ends even if there is an instruction to execute the printing operation or other maintenance until the specified time elapses. It does not shift to other operations. In the first mode, the fine vibration operation by the first signal unit CP1 is performed more frequently than in the second mode, so that the ink that has settled when the power is turned off is diffused while the ink thickening is suppressed.

When the prescribed execution time of the first mode ends at time t2, the execution of the fine vibration operation in the second mode is started with the nozzle surface of the printing head 5 being capped. In the second mode, since the duration T4 of the second signal portion CP2 is set longer than the duration T2 of the second signal portion CP2 in the first mode, the ink thickening is more reliably performed. While being suppressed, sedimentation of the pigment component in the ink is suppressed.
When the fine vibration operation in the second mode is being performed and the printer controller 45 is instructed to execute the printing operation at time t3, in the present embodiment, the obstacle detector 4 Detection of irregularities and obstacles on the surface of the material to be printed T is executed. The fine vibration operation in the second mode is continued in a state where the nozzle surface of the printing head 5 is capped until it is determined that the printing operation is possible without finally detecting an obstacle or the like. This allows the user to stretch the wrinkles on the surface of the material to be printed T to make it flat or to remove the obstacles such as foreign matters on the surface of the material to be printed T, while suppressing the thickening of the ink. Can be stirred. While the micro-vibration operation is being performed in the second mode, the CPU 47 determines whether the CPU 47 has elapsed time since the micro-vibration operation was started in the second mode or the micro-vibration driving pulse for the piezoelectric element 24. The number of times VP is applied is monitored, whether or not these have reached a predetermined upper limit value (or exceeded) is determined, and subsequent processing is changed according to the determination result. Details of this point will be described later.

  When it is determined that the printing operation is possible without detecting an obstacle at time t4, the nozzle surface of the printing head 5 is released from capping by the capping mechanism 7, and then the flushing operation (FL) is performed at time t5. Is called. Between these time points t4 and t5, the fine vibration operation in the third mode is continuously performed. As a result, the ink is sufficiently diffused. For this reason, the ink can be stirred to a state more suitable for the printing operation. In the above-described flushing operation, in addition to the ejection operation for printing an image or the like on the printing material T, ink is ejected from the nozzles 24 by a flushing drive pulse, thereby increasing the viscosity. In this operation, ink and bubbles are discharged to an ink receiving portion such as the cap member 7a. By performing this flushing operation before shifting to the printing operation, the thickened ink in the vicinity of the nozzle 34 and in the pressure chamber 32 is discharged, so that the viscosity of the ink in the nozzle 34 and the pressure chamber 32 is in an initial state (ink The state is restored to a state close to that stored in the cartridge. Then, from the time t6 when the flushing operation is completed to the time t7 when the carriage 17 moves from the home position toward the printing execution region 15 and the start of the printing operation is completed, the slight vibration in the third mode. The operation is performed continuously. As a result, the ink is sufficiently diffused to such an extent that an ejection abnormality does not occur during the printing operation.

  When the printing operation is started from time t7, a dedicated drive signal for forming an image or the like on the printing material T is generated from the drive signal generation unit 49 and output to the printing head 5, and this drive is performed. The piezoelectric element 24 is driven by the signal, and the printing operation is performed. The drive signal includes a fine vibration drive pulse in addition to the ejection drive pulse for ejecting ink, and is applied to the piezoelectric element 24 corresponding to the nozzle 34 to which ink is not ejected during the printing operation. Vibration is performed (so-called fine vibration in printing). When the printing operation is completed at time t8, the fine vibration operation in the third mode is continuously performed while the carriage 17 moves from the printing execution area 15 toward the home position. When the carriage 17 is positioned at the home position at time t9, the nozzle surface of the printing head 5 is capped by the capping mechanism 7, and the execution of the fine vibration operation in the second mode is started in this capping state.

  Here, while the fine vibration operation is being executed in the second mode, the CPU 47 monitors the elapsed time and the like since the start of the fine vibration operation in the second mode. It is determined whether or not a predetermined upper limit value has been reached. When it is determined that the elapsed time or the like has not reached the upper limit value, it is determined that the elapsed time or the like has reached the upper limit value, or until the next printing operation is instructed, or the printing printer 1 Until the power is turned off, the fine vibration operation in the second mode is continued. Then, when there is an instruction to execute the printing operation without the elapsed time of the fine vibration operation in the second mode reaching the upper limit value, maintenance such as a suction cleaning operation is performed after the fine vibration operation in the second mode. The operation is shifted to the printing operation without performing the operation. However, the present invention is not necessarily limited to this, and a maintenance operation can also be performed as necessary before shifting to the printing operation.

  On the other hand, if it is determined that the elapsed time or the like of the fine vibration operation in the second mode has reached the upper limit value, the CPU 47 stops the fine vibration operation in the second mode. As a result, ink thickening due to the minute vibration operation in the second mode being continued for a long time is suppressed. In this case, after the fine vibration operation is stopped, the maintenance operation is performed before the next printing operation is executed. In the present embodiment, the CPU 47 controls the circulation pump 50 to execute a circulation operation while the nozzle surface of the textile printing head 5 is capped, and negative pressure is applied to the internal space of the cap member 7a. Perform suction cleaning operation. As a result, ink thickened by the fine vibration operation in the second mode is discharged from the nozzle 34, and new ink is supplied into the pressure chamber 32 by the circulation operation. As a result, the viscosity of the ink in the printing head 5 is restored to a state suitable for the printing operation, so that it is possible to suppress the occurrence of ink ejection failure in the printing operation.

  Here, the upper limit value is within the range in which the ejection characteristics, that is, the amount (weight or volume) of the ink droplet ejected from the nozzle 34 and the flying speed of the ink droplet can be recovered to a value close to the target value by the maintenance operation. Is the upper limit of the elapsed time of the fine vibration operation. That is, when the fine vibration operation is performed exceeding this upper limit value, the ink may be thickened to the extent that it is difficult to recover the ejection characteristics even if a maintenance operation such as suction cleaning is performed thereafter. The upper limit value varies depending on the composition of the ink. For example, in the case of elapsed time, the upper limit value ranges from several tens of minutes to several hours. More specifically, in the case of white ink containing titanium dioxide, the upper limit is set to 8 hours, for example. The upper limit value for silver ink is also set to a value different from that for white ink. Therefore, determination of the upper limit value such as the elapsed time of the fine vibration operation in the second mode is performed for each ink type, that is, for each nozzle row. As a result, the fine vibration operation in the second mode can be stopped at a more appropriate timing according to the characteristics of the ink. Note that the elapsed time of the fine vibration operation in the second mode in the present embodiment includes both the time T3 of the first signal portion CP1 and the time T4 of the second signal CP2 in the second fine vibration drive signal vCOM2. Although it is the total execution time, for example, it may be the total of only the time T3 of the first signal unit CP1. In this case, it is necessary to set the upper limit value to a value corresponding thereto.

  As described above, the textile printer 1 according to the present invention employs a configuration in which the fine vibration operation is performed using the fine vibration drive signal that alternately generates the first signal portion CP1 and the second signal portion CP2. Each time the fine vibration operation for a predetermined time is performed, the fine vibration operation is stopped for a certain time. Accordingly, it is possible to stir the ink while suppressing the increase in the viscosity of the ink as compared with the configuration in which the fine vibration operation is continuously performed without being stopped halfway. As a result, it is possible to reduce the occurrence of ejection failure due to the sedimentation of the pigment in the configuration using the ink including the pigment having a relatively heavy specific gravity and easily settled. Further, the interval (so-called intermittent ability) that can be left without performing maintenance such as ejection of ink from the nozzle 34 or suction cleaning can be extended. Therefore, it is possible to reduce the frequency of suction cleaning and to suppress ink consumption. Furthermore, since the piezoelectric element 24 is not continuously driven, deterioration of the piezoelectric element 24 is suppressed, and also contributes to power saving.

The first mode in which the duration T2 of the second signal unit CP2 is set longer than the duration T1 of the first signal unit CP1, and the duration T4 of the second signal unit CP2 is the first mode. And a second mode that is set longer than the duration T2 of the ink, and can be selected from these modes. Therefore, when the textile printer 1 is turned on, the agitation effect is obtained in the first mode. By performing the micro-vibration operation with increased power, the pigment that has settled when the power is turned off can be more effectively diffused. After the micro-vibration operation in the first mode, the mode is switched to the second mode and the stop time is further increased. By performing the micro-vibration operation ensured for a long time, the ink can be diffused and settling can be suppressed while further suppressing the viscosity increase of the ink. Therefore, even in a situation where the power supply is turned off for a longer period of time, it is possible to suppress ink thickening and pigment settling to reduce ejection failure.
Further, when the fine vibration operation in the second mode is continuously performed, although the degree of ink thickening gradually proceeds as compared with the first mode, the elapsed time of the fine vibration operation in the second mode is gradually increased. Etc. reach a predetermined upper limit value, the micro-vibration operation is stopped, so that the ink thickening due to the micro-vibration operation in the second mode being continued for a long time is suppressed. As a result, it is possible to reduce the occurrence of ejection failure due to the thickening of the ink while ensuring the effect of suppressing the sedimentation of the pigment which is the ink-containing component.

  In the above-described embodiment, the first vibration change unit p11 that displaces the potential to the plus side with respect to the reference potential, the potential maintaining unit p12 that maintains the potential, and the potential is displaced to the minus side. The configuration of the second potential changing unit p13 that returns to the reference potential is illustrated, but the configuration is not limited thereto. For example, as shown in FIG. 10, a third potential changing unit p21 that shifts the potential to the negative side with respect to the reference potential Eb, a second potential maintaining unit p22 that maintains the potential, like a fine vibration drive pulse VP ′, It can also be configured with a fourth potential changing unit p23 for returning the potential to the reference potential.

  In each of the above-described embodiments, the so-called longitudinal vibration type piezoelectric element 24 is exemplified as the actuator. However, the actuator is not limited to this, and for example, a so-called flexural vibration type piezoelectric element can be employed. In this case, with respect to the exemplified drive signal, the waveform changes in the direction of potential change, that is, upside down.

  In the above embodiment, the duration T1 of the first signal unit CP1 in the first micro-vibration drive signal vCOM1 is the same as the duration T3 of the first signal unit CP1 in the second micro-vibration drive signal vCOM2. Although it is set to a value, it is not limited to this, and may be a different value.

  Moreover, in the said embodiment, although the injection failure by sedimentation of a coloring material (pigment) was illustrated, it is not restricted to it. For example, it is also effective for those that exist as solids in ink, such as resin particles, wax agents, preservatives, and the like.

Next, a second embodiment of the present invention will be described.
FIG. 11 is a front view illustrating the internal configuration of the printer 51 (a type of liquid ejecting apparatus) in the present embodiment. In this printer 51, a recording head 53, which is a type of liquid ejecting head, is mounted on a carriage 52 and attached to a guide lot 62 so as to be capable of reciprocating in the main scanning direction (left-right direction in FIG. 11) inside the housing. . The printer 51 receives ink from the nozzles of the recording head 53 while moving the recording head 53 in the main scanning direction relative to a recording medium (liquid landing target) such as recording paper conveyed and placed on the platen 60. By ejecting and landing the ink on a recording medium, an image or the like is recorded / printed. The configuration of the recording head 53 is substantially the same as that of the textile printing head 5 in the first embodiment. Further, the configuration of the drive signal for driving the piezoelectric element of the recording head 53 and each mode at the time of executing the fine vibration are the same as those in the first embodiment.

  A home position that is a standby position of the recording head 53 is set at a position deviated from one end side (right side in FIG. 11) in the main scanning direction with respect to the platen 60. In this home position, a capping mechanism 54 (capping part), a suction capping mechanism 56 (suction part), and a wiping mechanism 58 (wiping part) are provided in this order from one end side. The home position is provided with a flushing box 61 as a flushing region at the other end (left side in FIG. 11) in the main scanning direction across the platen 60. The capping mechanism 54 includes, for example, a cap 55 made of an elastic member such as an elastomer, and the cap 55 is in contact with the nozzle surface of the recording head 53 and sealed (capped state) or the nozzle. It is configured to be convertible to a retracted state separated from the surface. The cap 55 is formed in a tray shape having an opening on the surface that contacts the nozzle surface of the recording head 53, and is designed to have a size that can cover all nozzles on the nozzle surface. That is, when a plurality of nozzle rows (nozzle groups) composed of a plurality of nozzles are provided on the nozzle surface, all nozzle rows can be covered in a capped state. When the printer 51 is on standby, such as when the printer is turned off, the nozzle surface of the recording head 53 is in a capping state, thereby suppressing evaporation of the ink solvent from the nozzles. The cap 55 in the capping mechanism 54 can be replaced by the user.

  The suction capping mechanism 56 has a suction cap 57. Similarly to the capping mechanism 54, the suction cap 57 is in contact with the nozzle surface of the recording head 53 (capping state) or the nozzle surface. It can be converted into a retreat state separated from Similar to the cap 55, the suction cap 57 is formed in a tray shape having an open surface on the side in contact with the nozzle surface by an elastic member such as an elastomer. The suction cap 57 is designed to have a size that can cover the area of the nozzle row for one row. Although not shown, the suction capping mechanism 56 includes a drainage tube and a suction pump provided in the middle of the drainage tube. One end of the drainage tube is connected to a suction cap 57, and the other end communicates with a drainage tank (not shown). Then, the suction capping mechanism 56 operates the suction pump in a state where the region corresponding to the nozzle row to be sucked on the nozzle formation surface is capped by the suction cap 57, so that the inside of the sealed empty portion of the suction cap 57 is negatively affected. Compress. As a result, a so-called cleaning operation is performed to discharge thickened ink, bubbles, and the like from the nozzles of the capped nozzle row. By changing the capping position with respect to the nozzle surface, it is possible to sequentially perform the cleaning operation for each nozzle row. Unlike the cap 55 of the capping mechanism 54, the suction cap 57 in the suction capping mechanism 56 is not replaceable, but cleaning maintenance such as ink wiping is performed by the user depending on the situation. It is also possible to employ a configuration in which the capping mechanism 54 has a suction function without providing the suction capping mechanism 56 separately.

  The wiping mechanism 58 has a wiper 59 that can move along a direction (nozzle row direction) intersecting the main scanning direction, and the wiper 59 is in contact with the nozzle surface of the recording head 53. Or it is comprised so that conversion to the retreat state separated from the said nozzle surface is possible. The wiper 59 is made of, for example, an elastic blade body whose surface is covered with a cloth. The wiping mechanism 58 wipes the nozzle surface by sliding the wiper 59 from one side of the nozzle row to the other side in a state where the wiper 59 is in contact with the nozzle surface. The wiper 59 can be replaced by the user.

  The flushing box 61 includes a tray-shaped ink receiving portion 64 that receives ink ejected during the flushing operation for forcibly ejecting ink from the nozzles of the recording head 53 regardless of the recording operation on the recording medium. The position of the ink receiving portion 64 is fixed. One end of a drain tube (not shown) is connected to the ink receiver 64 and communicates with the drain tank. Further, a suction pump is provided in the middle of the drainage tube. By operating this suction pump, the ink in the ink receiving portion 64 is discharged to the drainage tank through the drainage tube.

Next, processing of the printer 51 when a maintenance operation such as replacement of parts is performed by the user in the present embodiment will be described.
FIG. 12 is a flowchart for explaining processing of the printer 51 during maintenance work. The maintenance work includes, for example, replacement work of the cap 55, the wiper 59, and the flushing box 61, or cleaning work of the suction cap 57. Then, for example, a work procedure or the like is displayed on a liquid crystal display unit or the like provided in the main body of the printer 51, and the user performs maintenance work according to the displayed procedure.

  Here, in the printer of the conventional configuration, during the maintenance work, the carriage is kept on standby at a position where the maintenance work is not hindered, for example, on the platen (recording area with respect to the recording medium). However, in this state, the meniscus at the nozzles of the recording head is exposed to the atmosphere, so that the viscosity of the ink tends to increase. In addition, when an ink in which the pigment easily settles is employed, there is also a problem that the precipitation of the pigment component proceeds. On the other hand, in the printer 51 according to the present invention, the standby position of the carriage 52 is made different according to the contents of the maintenance work, and further, the ink thickening or the pigment sedimentation is more appropriately performed according to the standby position of the carriage 52. The process which suppresses is performed.

  First, it is determined whether or not the carriage 52 can stand by above the flushing box 61 (step S1). The standby position of the carriage 52 is determined, for example, by having the user select / instruct the contents of maintenance. When it is determined that the carriage 52 can wait on the flushing box 61 (Yes), the carriage 52 is moved onto the flushing box 61 (position A in FIG. 11) until a predetermined operation is completed. The micro-vibration operation and the flushing operation (FL) in the third mode for a certain time are sequentially repeated. As a result, the ink is agitated by the micro-vibration operation in the third mode even during the maintenance work, so that the sedimentation of the pigment is suppressed. Further, if the fine vibration operation is continued, the viscosity of the ink increases. However, the ink is ejected by the flushing operation performed at regular intervals, so that the thickened ink is discharged to the flushing box 61. The viscosity is restored to a state close to the initial value. When the predetermined work is completed, it is determined whether or not another work different from the work is continued (step S12). Steps S12 and after will be described later.

  If it is determined in step S1 that standby on the flushing box 61 is not possible (No), it is then determined whether the carriage 52 can be standby in a capping state by the capping mechanism 54 (step S3). If it is determined that the camera can wait in the capping state (Yes), the carriage 52 is moved onto the capping mechanism 54 (position B in FIG. 11), and the nozzle surface of the recording head 53 is capped by the cap 55. . Then, until the predetermined maintenance work is completed, or until it is determined in step S5 described later that the elapsed time of the second mode has reached the upper limit value, slight vibration is caused in the second mode in this capping state. The action is executed. In the second mode, since the intermittent interval of the fine vibration operation is longer than that in the first mode, the sedimentation of the pigment component in the ink is reduced while the ink thickening is suppressed. By executing the fine vibration in the second mode in the capping state in this way, the sedimentation of the pigment is suppressed as much as possible. However, when the maintenance work is performed for a long time, or when the maintenance work is left in this state for a long time, the viscosity of the ink is increased although the progress is relatively slow. For this reason, while the fine vibration operation is being executed in the second mode, the CPU 47 monitors the elapsed time after the fine vibration operation in the second mode is disclosed, and the elapsed time etc. It is determined whether or not a predetermined upper limit value has been reached (step S5). If it is determined that the elapsed time or the like has not reached the upper limit (No), the process proceeds to step S12. On the other hand, when it is determined that the elapsed time or the like of the fine vibration operation in the second mode has reached the upper limit (Yes), the CPU 47 stops the fine vibration operation in the second mode, and performs the maintenance operation in step S9. A suction cleaning operation is executed (described later).

  During the execution of the fine vibration operation in the second mode in step S4, if the predetermined work is completed without the elapsed time of the fine vibration action exceeding the upper limit value, the work different from the work is continued. It is determined whether or not (step S12).

  If it is determined in step S3 that standby in the capping state is not possible (No), that is, in a situation where standby at both the home position and the flushing box 61 is difficult, the carriage 52 is positioned above the platen 60 (in FIG. 11). Wait at position C). In this case, the flushing operation cannot be performed on the platen 60. Further, if the slight vibration is continued in this state, the thickened ink is diffused in the pressure chamber, so that there is a possibility that the thickening proceeds to the entire ink in the recording head. For this reason, in this case, it waits without performing the flushing operation or the fine vibration operation until the predetermined work is completed (step S6). That is, the piezoelectric element (ACT) is not driven. Here, the degree of ink viscosity increase and the degree of pigment settling differ depending on the time required for the maintenance work. For this reason, the work time T is measured by a timer (not shown). A threshold value is set in advance for the work time T. Then, it is determined at the time when the work is completed whether or not the measured work time T is equal to or greater than a threshold value (step S7).

  When it is determined in step S7 that the work time T has become equal to or greater than the threshold (Yes), or in step S5, it is determined that the elapsed time of the fine vibration operation in the second mode has reached the upper limit (Yes). In this case, the ink is thickened to the extent that it cannot be recovered by the flushing operation. Therefore, in the former case, the carriage 52 is moved to the home position, and the nozzle surface of the printing head 5 is capped by the suction capping mechanism 56 (step S8). In the latter case, since the nozzle surface of the printing head 5 has already been capped, the process proceeds to step S9. In this state, in step 9, a suction cleaning operation is performed. That is, when the pump is operated in the capping state to make the internal space of the suction cap 57 have a negative pressure, the thickened ink is discharged from the nozzle. As a result, the viscosity of the ink inside the recording head 53 is restored to a state close to the initial state (the state stored in the ink cartridge). This suction cleaning operation is sequentially performed on each nozzle row. It should be noted that when the cleaning operation is performed, the circulation operation in the above embodiment can also be performed. If the cleaning operation is completed, it is determined whether or not another operation is continued (step S12).

  If it is determined in step S7 that the working time T is less than the threshold (No), the ink thickening is mild. For this reason, the carriage 52 is moved above the flushing box 61 (step S10), and the third mode fine vibration operation and flushing operation (FL) for a predetermined time are executed a predetermined number of times (step S11). As a result, the pigment that has settled during the maintenance work is diffused and the thickened ink is discharged from the nozzle. Thereafter, it is determined whether or not another operation is continued (step S12). If it is determined that another work is to be continued (Yes), the process returns to step S1, and the subsequent processing is executed according to the work content. On the other hand, if it is determined that the maintenance work has been completed without any other work being continued (No), and the carriage 52 is currently waiting at a place other than the capping mechanism 54, the carriage is placed on the capping mechanism 54. 52 is moved, and the nozzle surface of the recording head 53 is capped (step S13). In addition, when the carriage 52 is on standby with the nozzle surface of the recording head 43 capped by the capping mechanism 54, the capping state is continued. As described above, the processing of the printer 51 during the maintenance work is completed.

  As described above, in the present embodiment, when the recording head 53 mounted on the carriage 52 can stand by on the flushing box 61 in the maintenance work, the fine vibration operation and the flushing operation in the third mode are performed during the maintenance work. When the recording head 53 is able to stand by on the capping mechanism 54, the second mode fine vibration operation is executed in the capping state. Further, when the recording head 53 cannot stand by on the flushing box 61 or the capping mechanism 54, the recording head 53 waits without driving the piezoelectric element and measures the standby time (working time), and the measured time exceeds the threshold. If it becomes, the cleaning operation is executed. On the other hand, if the measured time becomes equal to or greater than the threshold value, the fine vibration operation and the flushing operation in the third mode are executed. That is, processing for suppressing ink thickening or pigment settling or recovery processing is performed according to the standby position of the carriage 52. For this reason, the execution of the flushing operation and the cleaning operation can be minimized, and ink consumption can be reduced. Further, when the elapsed time or the like of the fine vibration operation in the second mode reaches the upper limit value, the fine vibration operation is stopped, so that the ink caused by continuing the fine vibration operation in the second mode for a long time. The thickening is suppressed. As a result, it is possible to achieve both suppression of sedimentation of ink-containing components and suppression of ink thickening.

  The present invention can also be applied to other liquid ejecting apparatuses that handle liquid containing components that may cause sedimentation. For example, an ink-absorbing recording medium having an ink-absorbing layer such as paper, or a color filter such as a liquid ejecting apparatus that prints an image on a non-ink-absorbing recording medium having no ink-absorbing layer, such as plastic, or a liquid crystal display Manufacturing equipment, organic EL (Electro Luminescence) display, electrode manufacturing equipment for forming electrodes such as FED (surface emitting display), chip manufacturing equipment for manufacturing biochips (biochemical elements), very small amount of sample solution It can also be applied to micropipettes that supply the correct amount.

  DESCRIPTION OF SYMBOLS 1 ... Textile printer, 4 ... Obstacle detector, 5 ... Printing head, 7 ... Capping mechanism, 9 ... Tray moving part, 10 ... Carriage scanning part, 24 ... Piezoelectric element, 32 ... Pressure chamber, 34 ... Nozzle, 45 ... Printer controller 49... Drive signal generating unit 50. Circulating pump 51. Printer 52. Carriage 53 53 Recording head 54 Capping mechanism 55 Cap Cap 56 Capping mechanism 57 Suction cap 58 ... Wiping mechanism, 59 ... Wiper, 60 ... Platen, 61 ... Flushing box, 64 ... Ink receiving part

Claims (4)

A liquid ejecting head that ejects a liquid containing a pigment from a nozzle by driving an actuator;
Drive signal generating means for generating a fine vibration drive signal including a fine vibration waveform for driving the actuator to vibrate the liquid in the nozzle;
Control means for controlling a liquid ejecting operation by the liquid ejecting head,
The micro-vibration drive signal includes a first signal unit that generates a plurality of micro-vibration waveforms, and a second signal unit that maintains a constant potential,
A first mode in which a duration time of the second signal portion is set to a first time longer than a duration time of the first signal portion; and a duration time of the second signal portion is the first time A second mode set to a second time longer than the time can be selected;
The control means monitors the elapsed time of the fine vibration operation in the second mode, and when it is determined that the elapsed time has reached an upper limit value determined in advance according to the ease of thickening of the liquid , A liquid ejecting apparatus, wherein fine vibration operation in mode 2 is stopped.   The control means executes a maintenance operation for discharging liquid from the nozzle separately from the liquid ejecting operation before the next liquid ejecting operation is performed after the fine vibration operation in the second mode is stopped. The liquid ejecting apparatus according to claim 1. The liquid ejecting apparatus according to claim 1 , wherein the pigment contained in the liquid is titanium dioxide . A liquid ejecting head for ejecting a liquid containing a pigment from a nozzle by driving an actuator; a drive signal generating means for generating a micro vibration drive signal including a micro vibration waveform for driving the actuator to vibrate the liquid in the nozzle; Control means for controlling a liquid ejecting operation by the liquid ejecting head, and a control method for a liquid ejecting apparatus comprising:
  The micro-vibration drive signal includes a first signal unit that generates a plurality of micro-vibration waveforms, and a second signal unit that maintains a constant potential,
  A first mode in which a duration time of the second signal portion is set to a first time longer than a duration time of the first signal portion; and a duration time of the second signal portion is the first time A second mode set to a second time longer than the time can be selected;
  When it is determined that the elapsed time of the fine vibration operation in the second mode has reached the upper limit value determined in advance according to the ease of thickening of the liquid, the fine vibration operation in the second mode is stopped. A control method for a liquid ejecting apparatus.

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