JP2022172378A - Liquid discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to reduce a preservation liquid remaining in a head unit.

SOLUTION: A liquid discharge device comprises: a head unit having a nozzle and a liquid channel which is communicated with the nozzle and supplies a discharge liquid accumulated in a tank to the nozzle; a discharge part which discharges at least any one of the discharge liquid and a preservation liquid different from the discharge liquid existing in the liquid channel outside the liquid channel; an agitation part which agitates the liquid in the liquid channel; and a control part. The control part executes an introduction processing in which the control part controls the discharge part so as to discharge the preservation liquid in the liquid channel at least outside the liquid channel, an agitation processing in which the control part controls the agitation part so as to agitate the liquid in the liquid channel after the introduction processing, and a discharge processing in which the control part controls the discharge part so as to discharge the liquid in the liquid channel, which is agitated by the agitation part, outside the liquid channel after the agitation processing.

SELECTED DRAWING: Figure 8

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to a liquid ejection device.

As an example of a liquid ejecting apparatus, in the inkjet printer disclosed in Patent Document 1, an inkjet head and an ink flow path for supplying ink to the inkjet head are provided for the purpose of maintaining the function of the inkjet head when shipped from the factory. A filling liquid (storage liquid) different from the ink is filled in the head unit including the ink. In this inkjet printer, before the first printing (before the first use), an initial purge is performed to introduce ink from the ink cartridge into the inkjet head while discharging the filling liquid filled in the head unit from the nozzles. Thus, the filling liquid filled in the head unit is replaced with ink.

Japanese Patent Application Laid-Open No. 2012-91500

Here, if the storage liquid remains in the head unit when the inkjet printer is used, ink mixed with the storage liquid will be ejected from the head unit, resulting in deterioration of print quality. Therefore, in order to ensure print quality, it is necessary to sufficiently drain the storage liquid from the head unit before performing the first printing. However, the inventors of the present application have found that even if the initial purge is simply performed before the first printing, a large amount of the storage liquid may remain in the head unit.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a liquid ejecting apparatus capable of reducing the storage liquid remaining in the head unit.

In order to solve the above-described problems, a liquid ejecting apparatus according to a first aspect of the present invention includes a nozzle capable of ejecting an ejecting liquid, and communicating with the nozzle and supplying the ejecting liquid stored in a tank to the nozzle. and a head unit having a liquid flow path for discharging the liquid, which is at least one of the ejection liquid and a storage liquid different from the ejection liquid, existing in the liquid flow path, to the outside of the liquid flow path. an agitation part for agitating the liquid in the liquid channel; and a control part for controlling the agitation part and the agitation part. When the storage liquid is present in the liquid flow path, the control section controls the discharge section to discharge the storage liquid in the liquid flow path to at least the outside of the liquid flow path. an introduction process of introducing the discharge liquid from a tank into the liquid channel; a stirring process of controlling the stirring unit to stir the liquid in the liquid channel after the introduction process; and the stirring process. Afterwards, a discharge process is executed for controlling the discharge section to discharge the liquid stirred by the stirring section in the liquid channel to the outside of the liquid channel.

According to the above configuration, the storage liquid existing in the liquid channel is discharged after being mixed with the ejection liquid. can also be discharged out of the liquid channel. As a result, the storage liquid remaining in the head unit can be reduced.

A liquid ejecting apparatus according to a second aspect of the invention is the liquid ejection device according to the first aspect, wherein, in the introduction process, the controller controls a predetermined flow rate in the flow path in which the storage liquid exists before the start of the introduction process in the liquid flow path. The discharge section is controlled so that the air remains in the passage portion. According to the above configuration, during the agitation process, the storage liquid and the discharge liquid can be efficiently agitated in the predetermined channel portion by the air existing in the predetermined channel portion in the liquid channel.

A liquid ejecting apparatus according to a third aspect of the invention is the liquid ejecting apparatus according to the second aspect, wherein the tank includes a storage chamber for storing the ejection liquid, and a supply section for supplying the ejection liquid from the storage chamber to the outside of the tank. a tank mounting portion having a connected portion to which the tank is detachably mounted and which is connected to the supply portion of the tank when the tank is mounted to circulate the discharge liquid; The path is connected to the connected portion, and the control portion controls, in the introducing process, the liquid flow path when the supply portion of the tank and the connected portion of the tank mounting portion are connected. In order to move at least part of the air entering the flow path to the predetermined flow path portion of the liquid flow path, the total discharge amount of the liquid discharged from the liquid flow path to the outside of the liquid flow path is The discharge part is controlled so that the amount corresponds to the volume from the connection position with the connected part in the flow path to the predetermined flow path part. According to the above configuration, it is possible to reliably retain the air in the predetermined flow path portion.

A liquid ejecting apparatus according to a fourth aspect of the invention is the liquid ejecting apparatus according to the second or third aspect, wherein the head unit has the nozzles, a head body for ejecting the ejection liquid from the nozzles, and a liquid supply member for supplying the ejection liquid, the liquid flow path being formed in the head main body and having a supply port to which the ejection liquid is supplied from the liquid supply member; a supply channel formed in the liquid supply member and communicating between the supply port and the tank; the supply channel being connected to the supply port of the head channel; A first flow path extending upward from the mouth, and a second flow path connected to the tank-side end of the first flow path and extending in a direction intersecting the extending direction of the first flow path. wherein a connecting corner portion between the first flow channel and the second flow channel is positioned highest in the first flow channel and the second flow channel, and the control unit performs the introduction process In the above, the discharge section is controlled so that the air in the liquid flow path stays at the connection corner portion, with the predetermined flow path portion as the connection corner portion. According to the above configuration, since the first flow path of the supply flow path is a flow path extending upward from the supply port of the head flow path in the head main body, the air existing in the supply flow path reaches the head main body. It is difficult to move, and as a result, deterioration of ejection characteristics of the head body due to air entering the head body can be suppressed. In addition, although the connection position between the first flow channel and the second flow channel is a flow channel portion where the storage solution tends to stay, the storage solution existing at this connection position is removed by the agitation process. Since it can be moved to a part, it is possible to reduce the storage solution remaining at this connection position after the discharge process.

A liquid ejecting apparatus according to a fifth aspect of the invention is the liquid ejecting apparatus according to the second or third aspect, wherein the head unit has the nozzles, a head body for ejecting the ejection liquid from the nozzles, and a liquid supply member for supplying the ejection liquid, the liquid flow path being formed in the head main body and having a supply port to which the ejection liquid is supplied from the liquid supply member; A supply channel is formed in the liquid supply member and communicates between the supply port and the tank, and the supply channel includes a damper chamber for suppressing pressure fluctuations of the liquid supplied to the head body. In the introduction process, the control section controls the discharge section so that the air in the liquid flow path stays in the damper chamber with the predetermined flow path portion as the damper chamber. According to the above configuration, the damper chamber has a channel portion where the storage liquid tends to stay, but the stirring process can move the storage liquid existing in the damper chamber to the channel portion where it does not easily stay. Therefore, it is possible to reduce the storage liquid remaining in the damper chamber after the discharge process.

According to a sixth aspect of the invention, there is provided a liquid ejecting apparatus according to any one of the second to fifth aspects of the invention, which is connected to the liquid flow path and is in a state in which the exhaust flow path is connected to discharge air and the exhaust flow path is open. and a switching means for switching between a closed state and a closed state, wherein the discharge section is connectable to the exhaust flow path opened by the switching means, and the control section, after the discharge process, An exhaust process for exhausting the air in the liquid flow path through the exhaust flow path is further performed by controlling the discharge section and the switching means. According to the above configuration, it is possible to suppress the deterioration of the ejection characteristics of the ejection liquid of the head unit due to the air present in the liquid flow path.

A liquid ejecting apparatus according to a seventh aspect of the invention is the liquid ejecting apparatus according to any one of the second to fifth aspects, wherein the discharge section includes a cap attachable to the head unit so as to cover the nozzles, and a cap connected to the cap. and a suction pump, and driving the suction pump to suck the inside of the cap while the cap is attached to the head unit, thereby discharging the liquid and air in the liquid flow path from the nozzle. wherein, in the discharge process, the control section controls the purge unit to perform a purge to discharge the liquid in the liquid flow path from the nozzle, and the discharge process After that, the purge unit is controlled to further perform an exhaust process for purging the air in the liquid flow path through the nozzle, and in the purge of the exhaust process, the liquid is discharged from the nozzle. In order to discharge the air in the flow path, the suction force of the suction pump is made stronger than the suction force of the suction pump during the purge of the discharge process. According to the above configuration, since the exhaust process is performed after the exhaust process, it is not necessary to exhaust the air present in the liquid flow path during the exhaust process. As a result, since it is not necessary to drive the suction pump with a strong suction force in the purge of the discharge process, it is possible to suppress excessive discharge of the discharge liquid during the discharge process.

A liquid ejecting apparatus according to an eighth aspect of the invention is the liquid ejecting apparatus according to any one of the second to fifth aspects, wherein the head unit, as the ejecting section, has energy for causing the liquid in the liquid flow path to eject from the nozzles. and the discharge section includes a cap attachable to the head unit so as to cover the nozzle, and a suction pump connected to the cap, wherein the cap is attached to the head a purge unit for discharging the liquid and air in the liquid flow path from the nozzle by driving the suction pump and sucking the inside of the cap while the cap is attached to the unit; and performing flushing by controlling the energy imparting unit to eject and discharge the liquid in the liquid flow path from the nozzle in the discharging process, and controlling the purge unit after the discharging process. Then, an exhaust process is further executed to perform purging for exhausting the air in the liquid flow path from the nozzle. According to the above configuration, since the exhaust process is performed after the exhaust process, it is not necessary to exhaust the air present in the liquid flow path during the exhaust process. As a result, in the discharge process, the liquid in the liquid flow path can be discharged to the outside of the liquid flow path by flushing, which discharges a smaller amount of liquid than the purge process. can be suppressed.

According to a ninth aspect of the invention, in any one of the sixth to eighth aspects of the invention, the control unit repeatedly executes the stirring process and the discharge process as a set a plurality of times. According to the above configuration, the storage liquid remaining in the head unit can be reliably reduced by executing the stirring process and the discharging process multiple times. Further, in the discharging process, the liquid is discharged to the outside of the liquid channel with a weaker force than in the exhausting process, so air can be retained in a predetermined channel portion of the liquid channel. As a result, when each stirring process is performed, air remains in the predetermined flow path portion, so that the storage liquid and the ejection liquid can be efficiently stirred in the predetermined flow path portion.

According to a tenth aspect of the invention, there is provided a liquid ejection apparatus according to any one of the first to ninth aspects, wherein the stirring section has a carriage on which the head unit is mounted and which reciprocates along with the head unit in a predetermined scanning direction. wherein the control unit includes
In the stirring process, the carriage is controlled to reciprocate the head unit in the scanning direction so as to stir the liquid in the liquid flow path. According to the above configuration, the configuration of the stirring section can be simplified.

A liquid ejection apparatus according to an eleventh aspect of the invention is the liquid ejection apparatus of the tenth aspect, wherein the stirring section further includes a moving mechanism for moving the head unit in a direction different from the scanning direction, and the control section performs the stirring process. In the above, when the head unit reciprocates in the scanning direction, the moving mechanism is controlled to move the head unit in a direction different from the scanning direction. According to the above configuration, it is possible to further improve the efficiency of stirring the storage liquid and the ejection liquid.

A liquid ejecting apparatus according to a twelfth aspect of the invention is, in the tenth or eleventh aspect, arranged in a partial range of the movement range of the head unit in the scanning direction, and ejecting liquid from the nozzles of the head unit. The control unit repeatedly executes the stirring process and the discharge process as a set a plurality of times, and controls the stirring part in each of the stirring processes. and moving the head unit forward in the scanning direction from the origin position with the liquid receptacle as the origin position, and then moving the head unit back to the origin position. to discharge the liquid in the liquid channel from the nozzle of the head unit toward the liquid receiver. According to the above configuration, the reciprocating movement of the head unit is performed with the liquid receptacle from which the liquid in the liquid flow path is discharged in the discharge process as the origin position, so that the processing time required for the stirring process and the discharge process can be shortened. can be done.

A liquid ejecting apparatus according to a thirteenth aspect of the invention is the liquid ejecting apparatus according to any one of the first to twelfth aspects of the invention, wherein the head unit, as the ejecting section, has an energy for causing the liquid in the liquid flow path to eject from the nozzles. wherein the control unit repeatedly executes the stirring process and the discharging process as a set a plurality of times, and in each of the discharging processes, the energy applying part is controlled to , flushing is performed by ejecting and discharging the liquid in the liquid flow path from the nozzle; According to the above configuration, it is possible to reliably reduce the amount of the storage liquid remaining in the head unit by repeatedly executing the stirring process and the discharging process as a set a plurality of times. Further, in each discharge process, the liquid is discharged by flushing, which makes it easy to adjust the discharge amount of the liquid. Therefore, it is possible to prevent excess discharge liquid from being discharged in each discharge process.

In the present invention, it is possible to reduce the storage liquid remaining in the head unit.

1 is a schematic configuration diagram of an inkjet printer according to an embodiment; FIG. 1 is a block diagram schematically showing an electrical configuration of an inkjet printer; FIG. 1 is a perspective view of an inkjet head; FIG. (a) and (b) are vertical cross-sectional views taken along line IV-IV in FIG. 2 is a plan view of a head body of an inkjet head; FIG. (a) is an enlarged view of part A in FIG. 5, and (b) is a cross-sectional view taken along line BB of (a). (a) and (b) are plan views for explaining the stirring process, and (c) is a diagram showing the relationship between the moving speed and the position of the carriage. 4 is a flowchart for explaining processing operations of an inkjet printer; (a) And (b) is a top view explaining a moving mechanism. FIG. 11 is a block diagram schematically showing an electrical configuration of an inkjet printer according to a modification;

A schematic configuration of an inkjet printer 1 (liquid ejection device) according to a preferred embodiment of the present invention will be described. As shown in FIG. 1, the printer 1 includes a platen 2, a carriage 3, an inkjet head 5 (hereinafter also simply referred to as head 5), a holder 6, a paper feed roller 7, a paper discharge roller 8, a cap unit 9, a switching device 10, and a , a suction pump 11, a waste liquid tank 12, a flushing receiver 30, a display 99 (see FIG. 2), a control device 100 (see FIG. 2), and the like. In the following description, the front side of the paper surface of FIG. Further, the front-back direction and the left-right direction shown in FIG. 1 are defined as the “front-back direction” and the “left-right direction” of the printer 1 . In the following description, directional terms such as front/rear, left/right, and up/down are appropriately used.

A sheet P, which is a recording medium, is placed on the upper surface of the platen 2 . Two guide rails 15 and 16 are provided above the platen 2 and extend in parallel in the horizontal direction (scanning direction).

The carriage 3 is attached to two guide rails 15 and 16 and is movable in the scanning direction along the two guide rails 15 and 16 in a region facing the platen 2 . A drive belt 17 is attached to the carriage 3 . The drive belt 17 is an endless belt wound around two pulleys 18 and 19 . One pulley 18 is connected to a carriage drive motor 20 (see FIG. 2). The carriage drive motor 20 rotates the pulley 18 to drive the drive belt 17, thereby reciprocating the carriage 3 in the scanning direction. At this time, the head 5 mounted on the carriage 3 reciprocates along with the carriage 3 in the scanning direction.

The holder 6 includes four cartridge mounting portions 41 to which ink cartridges 42 (corresponding to tanks) of four colors (black, yellow, cyan, and magenta) are detachably mounted. Each ink cartridge 42 includes a storage chamber 42a for storing ink, and a discharge pipe 42b (corresponding to a supply section) connected to the storage chamber 42a. The discharge pipe 42 b defines a channel for supplying the ink stored in the storage chamber 42 a to the outside of the ink cartridge 42 . The cartridge mounting portion 41 includes a needle 41a (corresponding to a connected portion) that is connected to the discharge pipe 42b to circulate ink when the ink cartridge 42 is mounted. Further, the cartridge mounting portion 41 is provided with a sensor 41b (see FIG. 2) for detecting whether or not the ink cartridge 42 is mounted in the cartridge mounting portion 41. As shown in FIG.

The head 5 is detachably attached to the carriage 3 as mentioned above.
The head 5 includes a head main body 13 and a sub-tank 14 (corresponding to a liquid supply member). A tube joint 21 is provided on the upper surface of the sub-tank 14 , and one end of each of four ink supply tubes 22 is detachably connected to the tube joint 21 . The other end of each of the four ink supply tubes 22 is connected to each of the needles 41 a of the four cartridge mounting portions 41 of the holder 6 . The ink in the four ink cartridges 42 attached to the cartridge attachment portion 41 is supplied to the sub-tank 14 via the four ink supply tubes 22, respectively.

Further, the sub-tank 14 is provided with four exhaust portions 23 corresponding to the four colors of ink for exhausting the air existing in the ink flow path inside the sub-tank 14 before it moves to the head main body 13 . A valve (not shown) for switching communication/closure with the outside is installed inside each of the four exhaust units 23 .

The head body 13 is attached to the lower portion of the sub-tank 14 . The head main body 13 has a plurality of nozzles 44 on its lower surface and ejects ink supplied from the sub-tank 14 .
The plurality of nozzles 44 are arranged in correspondence with the four colors of ink, respectively, to form four nozzle rows. The channel structure inside the head body 13 will be described in detail later.

The paper feed roller 7 and the paper discharge roller 8 are synchronously driven to rotate by a transport motor 29 (see FIG. 2). The paper feed roller 7 and the paper discharge roller 8 cooperate to transport the paper P placed on the platen 2 in the transport direction shown in FIG.

The printer 1 conveys the paper P in the conveying direction by the paper feed roller 7 and the paper discharge roller 8, and moves the head 5 together with the carriage 3 in the scanning direction to eject ink onto the paper P in a desired manner. Record images, etc. That is, the printer 1 of this embodiment is a serial inkjet printer.

The cap unit 9 is located on one side of the platen 2 in the scanning direction (on the right side in FIG. 1), and vertically faces the cap unit 9 when the carriage 3 moves to the right side of the platen 2 . Also, the cap unit 9 is driven by a cap driving motor 24 (see FIG. 2) and can move up and down in the vertical direction. This cap unit 9 includes a nozzle cap 25 and an exhaust cap 26 that can be attached to the head 5 .

When the carriage 3 faces the cap unit 9 , the nozzle cap 25 faces the lower surface of the head body 13 , and the exhaust cap 26 faces the lower surfaces of the four exhaust portions 23 of the sub tank 14 . When the cap unit 9 is lifted while the carriage 3 and the cap unit 9 face each other, the cap unit 9 is attached to the head main body 13 and the sub-tank 14 . At this time, the nozzle cap 25 commonly covers all the nozzles 44 belonging to the four nozzle rows, and the exhaust cap 26 is connected to the four exhaust portions 23 . Attached to the exhaust cap 26 are four rod-shaped opening/closing members 27 that open and close the valves in the four exhaust portions 23, respectively. Although detailed description is omitted, the four rod-shaped opening/closing members 27 are vertically driven by an exhaust motor 28 (see FIG. 2) in a state where the exhaust cap 26 is connected to the four exhaust portions 23. By being inserted into the exhaust part 23, the internal valve is driven.

The nozzle cap 25 and the exhaust cap 26 are connected to the suction pump 11 via the switching device 10 . The switching device 10 selectively switches the communication destination of the suction pump 11 between the nozzle cap 25 and the exhaust cap 26 . Also, the suction pump 11 is connected to the waste liquid tank 12 . By switching the communication destination of the switching device 10, a suction purge that forcibly discharges ink from all the nozzles 44 belonging to the four nozzle rows, and an exhaust purge that exhausts air from the ink flow path in the sub-tank 14 are performed. can be selectively executed.

In the suction purge, the nozzle cap 25 is attached to the head main body 13 and covers the plurality of nozzles 44, and the suction pump 11 is connected to the nozzle cap 25 by the switching device 10. After that, the suction pump 11 is driven and the nozzles are purged. The inside of the cap 25 is depressurized (sucked) to suck and discharge the ink from the plurality of nozzles 44 of the head 5 . As a result, foreign substances, air bubbles, and ink that has become highly viscous due to drying can be discharged from the nozzles 44 in the head 5, and the ejection characteristics of the nozzles 44 can be recovered.

In the exhaust purge, the suction pump 11 is connected to the exhaust cap 26 by the switching device 10 in a state in which the exhaust cap 26 is connected to the exhaust portion 23 and the valve in the exhaust portion 23 is opened by the opening/closing member 27. The suction pump 11 is driven to apply negative pressure to the exhaust section 23 . As a result, air such as air bubbles grown in the ink flow path of the sub-tank 14 can be exhausted from the exhaust section 23 before it moves to the head main body 13 .

Ink and storage liquid discharged from the head 5 by suction purge or exhaust purge are sent to a waste liquid tank 12 connected to a suction pump 11 .

Further, in the present embodiment, the head 5 performs flushing by ejecting ink from each of the plurality of nozzles 44 at an appropriate timing. The purpose of this flushing is various, but for example, it is to prevent the ink inside the nozzle 44 from drying, or to adjust the meniscus inside the nozzle 44 after the suction purge.

The flushing receiver 30 is a member for receiving ink or the like ejected from the plurality of nozzles 44 during this flushing. The flushing receiver 30 is arranged at the left end position (hereinafter also referred to as the origin position) within the moving range of the head 5 in the scanning direction. That is, the flushing receiver 30 is arranged on the other side of the platen 2 in the scanning direction.

When the head 5 moves to the origin position for flushing (see FIG. 7A), the head 5 vertically faces the flushing receiver 30 . When flushing is performed in this state, ink ejected from the plurality of nozzles 44 of the head 5 is received by the flushing receiver 30 .

As shown in FIG. 2, the control device 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a control circuit 104, a bus 105, and the like. The ROM 102 stores programs executed by the CPU 101, various fixed data, and the like. The RAM 103 temporarily stores data (image data, etc.) necessary for program execution. The control circuit 104 is connected to various devices or drive units of the printer 1, such as the driver IC 53 of the head 5, the carriage drive motor 20, the cap drive motor 24 that moves the cap unit 9 up and down. The control circuit 104 is also connected to an external device 31 such as a PC. The CPU 101 controls the head 5, the carriage driving motor 20, etc. via the control circuit 104 based on the recording command transmitted from the external device 31, and causes the paper P to record an image or the like. The CPU 101 also controls the switching device 10, the suction pump 11, and the like via the control circuit 104 to perform the suction purge and the exhaust purge described above.
Note that in the present embodiment, the control device 100 is configured to execute each process by a single CPU, but a plurality of CPUs, a single application specific integrated circuit (ASIC), a plurality of ASICs, or , a combination of a CPU and a specific ASIC may be configured to execute each process.

Next, the head 5 will be described with reference to FIGS. 3 to 6. FIG. In FIG. 3, the opening/closing member 27 for opening/closing the exhaust portion 23 of the sub-tank 14 is also indicated by a two-dot chain line. 4, the head main body 13 is not shown in cross section but is shown in side view.

As shown in FIGS. 5 and 6, the head body 13 of the head 5 includes a channel unit 33 and a piezoelectric actuator 34 (corresponding to an energy applying section). As shown in FIG. 6B, the channel unit 33 has a structure in which five plates 35 to 39 are stacked. The lowest layer plate 39 among the five plates 35 to 39 is a nozzle plate 39 in which a plurality of nozzles 44 are formed. On the other hand, the remaining four plates 35 to 38 on the upper side are formed with channels such as manifolds 46 communicating with the plurality of nozzles 44 and pressure chambers 47 .

As shown in FIG. 5, four ink supply holes 45 are formed side by side in the scanning direction on the upper surface of the channel unit 33 . The four ink supply holes 45 are connected to the sub-tank 14, and four color inks are supplied from the sub-tank 14, respectively. Further, the channel unit 33 has four manifolds 46 each extending in the transport direction inside thereof. Four manifolds 46 are connected to four ink supply holes 45 .

As shown in FIG. 4 , a filter 49 is stretched over the upper surface of the four ink supply holes 45 to remove dust and the like from the ink supplied from the supply flow path 62 . Also, the filter 49 makes it difficult for the air in the supply channel 62 to flow into the head main body 13 .

Furthermore, the channel unit 33 has a plurality of nozzles 44 opening on its lower surface, and a plurality of pressure chambers 47 communicating with the plurality of nozzles 44 respectively. As shown in FIG. 5, in plan view, the plurality of nozzles 44 are arranged in four rows corresponding to the four manifolds 46, respectively. The plurality of pressure chambers 47 are also arranged in four rows corresponding to the four manifolds 46 in the same manner as the plurality of nozzles 44 . As shown in FIG. 6B, each pressure chamber 47 communicates with the corresponding manifold 46 . With the above configuration, as indicated by arrows in FIG. 6B, a plurality of individual flow paths are formed in the flow path unit 33, branching from each manifold 46 and reaching the nozzles 44 via the pressure chambers 47. there is In the following, the ink channels such as the manifold 46, the pressure chambers 47, the nozzles 44, etc. formed in the channel unit 33 are collectively referred to as a head channel 48 (see FIG. 4).

As shown in FIGS. 5 and 6, the piezoelectric actuator 34 includes a vibration plate 50, piezoelectric layers 54 and 55, a plurality of individual electrodes 52, and a common electrode . The vibration plate 50 is joined to the upper surface of the channel unit 33 while covering the plurality of pressure chambers 47 . Two piezoelectric layers 54 and 55 are laminated on the upper surface of diaphragm 50 . The plurality of individual electrodes 52 are arranged on the upper surface of the upper piezoelectric layer 55 so as to face the plurality of pressure chambers 47 respectively. The common electrode 56 is arranged across the plurality of pressure chambers 47 between the two piezoelectric layers 54 and 55 .

When a drive signal is supplied from the driver IC 53 to the individual electrodes 52 of the piezoelectric actuator 34 in response to a signal from the control device 100, piezoelectric strain occurs in the portion of the upper piezoelectric layer 55 facing the pressure chamber 47. , the diaphragm 50 is deformed so as to bend. At this time, the pressure (energy) is applied to the ink in the individual flow path by changing the volume of the pressure chamber 47 , and the ink is ejected from the nozzle 44 .

Next, the sub-tank 14 will be described in detail. The sub-tank 14 is a member molded of synthetic resin. As shown in FIGS. 3 and 4, a plate-like body portion 60 extends along a horizontal plane, and one end of the body portion 60 extends vertically downward. and a connecting portion 61 .

The sub-tank 14 is formed with four supply channels 62 for supplying inks of four colors to the head main body 13 . The body portion 60 is formed with four ink introduction portions 64 corresponding to the four colors of ink. The four supply channels 62 are connected to the four color ink introduction portions 64, respectively. The four ink introduction portions 64 are provided on the upper surface of the flat plate-like body portion 60 . Note that FIG. 3 shows only the connection structure of the supply flow path 62 corresponding to one color of ink. The four color inks introduced from the four ink introduction portions 64 of the sub-tanks 14 flow into the head flow paths 48 of the head main body 13 via the supply flow paths 62 .

A tube joint 21 is attached to the upper surface of the body portion 60 . Connected to the tube joint 21 are four ink supply tubes 22 each connected to an ink cartridge 42 (see FIG. 1). are formed to communicate with each other.

Each supply channel 62 has a body channel 70 (corresponding to the second channel) formed in the body portion 60 and a connecting channel 75 (corresponding to the first channel) formed in the connecting portion 61. . The main flow path 70 extends along the horizontal plane, as shown in FIG. On the other hand, the connecting channel 75 is connected to one end of the main channel 70 and extends vertically downward from this one end. As a result, a connecting corner 90 forming a 90-degree angle is formed at the connecting portion between the main flow channel 70 and the connecting flow channel 75 . This connection corner portion 90 is the uppermost position in the main flow channel 70 and the connecting flow channel 75 , similarly to each position of the main flow channel 70 . As a modification, at least a part of the main flow channel 70 on the side of the connecting flow channel 75 (for example, a flow channel 73 to be described later) may extend downward from the connecting portion with the connecting flow channel 75. .

The main flow path 70 has a damper chamber 71 and flow paths 72 and 73 arranged in front of and behind the damper chamber 71 . The damper chambers 71 are concave portions formed on the surface of the main body portion 60, and four damper chambers 71 corresponding to the four colors of ink are provided on the upper surface side and the lower surface side of the main body portion 60, two each. . Further, as shown in FIG. 4, the damper chamber 71 on the upper surface side and the damper chamber 71 on the lower surface side are arranged back to back. Also, the ink introduction portion 64 formed on the upper surface of the main body portion 60 and the damper chamber 71 are connected by a groove-like flow path 72 also formed on the upper surface of the main body portion 60 .

Furthermore, the damper chamber 71 is connected to a connecting channel 75 formed in the connecting portion 61 by a channel 73 formed in the upper surface of the body portion 60 . Although not shown in FIG. 3 for the sake of simplification of the drawing, the ink introduction portion 64, the damper chamber 71, and the connecting passage 75 for other colors of ink are also located on the upper surface of the main body portion 60 or A supply channel 62 is configured by being connected by a channel formed on the lower surface.

The main body portion 60 is also formed with four groove-shaped exhaust flow paths 74 that connect the four connection flow paths 75 and the four exhaust portions 23, respectively. For the sake of simplification of the drawing, only one exhaust passage 74 formed on the upper surface of the main body portion 60 is shown, and other exhaust passages 74 are omitted.

As shown in FIGS. 3 and 4, flexible films 78 and 79 made of a resin material are welded to the upper and lower surfaces of the body portion 60, respectively. As a result, the concave damper chamber 71 and the groove-shaped channels 72 and 73 of the supply channel 62 and the groove-shaped exhaust channel 74 formed in the body portion 60 are moved upward or downward by the films 78 and 79. It is covered from below.

The concave damper chamber 71 and the flow paths 72 and 73 before and after it have substantially the same depth, but the flow path width of the damper chamber 71 is considerably larger than that of the groove-shaped flow paths 72 and 73 . As a result, the supply channel 62 has a channel shape with a locally increased volume in the damper chamber 71 . When the ink is consumed in the head body 13, the pressure of the ink in the head body 13 decreases, so that the ink is supplied from the ink cartridge 42 to the supply channel 62 in the sub-tank 14 accordingly. At that time, if a large pressure fluctuation occurs in the ink in the supply channel 62, it is transmitted to the head main body 13 and adversely affects ink ejection. However, since the supply channel 62 is provided with the damper chamber 71 which has a large volume and is covered with the flexible films 78 and 79, the pressure fluctuation generated in the ink in the supply channel 62 is suppressed by the damper chamber 71. absorbed by

The four connecting channels 75 formed in the connecting portion 61 are closed at their upper ends with films 78 and 79 and are connected to the four ink supply holes 45 of the head 5 at their lower ends. As mentioned above, the connecting channel 75 extends in the vertical direction, and the connection corner 90 between the connecting channel 75 and the main channel 70 is the uppermost part of these channels 70 and 75. Because of this position, the air present in the supply channel 62 tends to remain at the upper end of the connecting channel 75 without flowing into the head main body 13 . As a result, deterioration of ejection characteristics of the head 5 due to air existing in the supply flow path 62 flowing into the head main body 13 can be suppressed. Further, as shown in FIG. 4, the connecting channel 75 is composed of an upper channel 76 having a large channel cross-sectional area (channel width) and a lower channel 77 having a small channel cross-sectional area. .

In the following description, for convenience of explanation, the flow path composed of the supply flow path 62 and the head flow path 48 will be referred to as an in-head flow path 80 . In addition, the entire flow path from the connection position of the ink supply tube 22 with the ink cartridge 42 to the plurality of nozzles 44, which is composed of the in-head flow path 80, the ink supply tube 22, and the in-joint flow path 21a, is filled with all the ink. This is referred to as channel 85 (see FIG. 1). All of the ink channels 85 correspond to the "liquid channel" of the present invention. Also, a unit composed of the head 5, the tube joint 21, and the ink supply tube 22 corresponds to the "head unit" of the present invention.

In the head 5 described above, as shown in FIG. 4(a), before shipping the head 5 from the factory, for the purpose of functional maintenance of the head 5, all the ink flow paths 85, such as the in-head flow path 80, are filled. , the storage solution is filled. Here, if, for example, a pigment-based ink is used as the storage liquid, the following problems arise. Coloring materials used in pigment-based inks may aggregate over time. Therefore, if the in-head flow path 80 of the head 5 is filled with pigment-based ink for a long period of time, there is a possibility that ejection failure will occur.

Therefore, in the present embodiment, a liquid containing less or no coloring material such as a dye or a pigment is used as the storage liquid compared to the ink. This preservative is considerably less expensive than ink because it contains less colorant than ink. Further, the storage liquid has a surface tension lower than that of the ink due to the addition of a surfactant so that the storage liquid can be easily introduced into the details of the in-head channel 80 when it is filled into the in-head channel 80 . .

Then, after shipment, when the power of the printer 1 in which the purchased head 5 is mounted is turned on for the first time by the user, the control device 100 causes the storage liquid filled in the in-head channel 80 of the head 5 to A replacement process is executed to replace with the ink introduced from the ink cartridge 42 .

Here, when the control device 100 performs a discharge process for discharging the liquid inside the head internal flow path 80 to the outside of the head internal flow path 80, such as suction purging or flushing, the amount of liquid discharged from the ink cartridge 42 is removed from the head. Ink is introduced into the inner channel 80 . Therefore, it is possible for the control device 100 to replace the liquid in the in-head flow path 80 with ink by executing this discharge process in the replacement process. However, the inventor of the present application has found that a large amount of the storage liquid remains in the in-head channel 80 only by performing this discharge process.
The reason is explained below. In the following description, it is assumed that all the ink flow paths 85 are filled with the storage liquid at the start of the replacement process (before the start of the introduction process, which will be described later).

As described above, the damper chamber 71 is a locally swollen flow passage portion having a flow passage cross-sectional area larger than that of the flow passages 72 and 73 before and after the damper chamber 71. There is a stagnation part where it is easy to In addition, since the connection corner 90 between the main flow channel 70 and the connecting flow channel 75 is a flow channel portion where the direction of the liquid flow changes downward, there is likely to be a location where the liquid flow is relatively slow. Liquids tend to stay. The storage liquid existing in the flow path portion where such liquid tends to stay is not kept in the nozzles 44 even if the flow of the liquid from the ink cartridge 42 toward the nozzles 44 is generated in all the ink flow paths 85 by flushing or suction purge. difficult to eject from As a result, if the discharge process is simply performed, a large amount of the storage liquid remains in the predetermined channel portion where the liquid in the head internal channel 80 tends to stay. In this way, if the ink containing the storage liquid is ejected from the nozzles 44 when the storage liquid remains in the internal head flow path 80, the quality of the image recorded on the paper P is deteriorated. be.

Therefore, in the present embodiment, in the replacement process, the controller 100 performs an introduction process of introducing ink into the in-head flow path 80 and agitating the liquid in the in-head flow path 80 in addition to the discharge process described above. The agitation process is executed before the discharge process. Note that the control device 100 repeatedly executes the stirring process and the discharging process as a set N times (N is an integer equal to or greater than 2: 85 times in this embodiment). In addition, in the replacement process, the control device 100 executes the exhaust process of exhausting the air in the in-head flow path 80 after repeating the stirring process and the exhaust process. A series of replacement processing flows will be described in detail below.

First, the control device 100 controls the cap unit 9 and the suction pump 11 to discharge at least a portion of the storage liquid in the in-head flow path 80 to the outside of the in-head flow path 80 to remove all the ink from the ink cartridge 42 . An introduction process for introducing ink into the flow path 85 is executed. Specifically, in the introduction process, the control device 100 performs an exhaust purge to exhaust excess air present in the supply flow path 62 . Thereafter, the control device 100 performs suction purge so that the ink in the ink cartridge 42 reaches the connecting corner 90 between the main flow path 70 and the connection flow path 75 in the supply flow path 62 .

Also, during this introduction process, the control device 100 controls the presence of the storage liquid in the in-head channel 80 before the start of the introduction process for the purpose of improving the stirring efficiency of the liquid during the subsequent stirring process, and 2) controls the suction pump 11 so that at least part of the air in all the ink flow paths 85 stays in a predetermined flow path portion where the liquid tends to stay. In this embodiment, the control device 100 controls the suction force and driving time of the suction pump 11 so that the air stays at the connecting corner 90 between the main flow path 70 and the connecting flow path 75 . Specifically, the control device 100 determines that the total discharge amount of the liquid discharged from the supply channel 62 to the outside of the supply channel 62 during the exhaust purge and the suction purge is equal to the connection position with the needle 41a in all the ink channels 85. , the suction pump 11 is controlled so as to have an amount corresponding to the volume from the connecting corner portion 90 to the connecting corner portion 90 . As a result, when the ink cartridge 42 is attached to the cartridge mounting portion 41 and the ink cartridge 42 is connected to all the ink flow paths 85, at least part of the air (such as entrapped air) that enters into all the ink flow paths 85 can be removed. , to the connection corner 90 between the main channel 70 and the connecting channel 75 . It should be noted that this "total discharge amount" is a discharge amount converted by regarding the air discharged by the exhaust purge or the like in the introduction process as liquid. Therefore, this total displacement may differ from the amount of liquid actually displaced by the amount of air displaced. Further, in this embodiment, in the suction purge during the introduction process, the rotational speed (suction force) of the suction pump 11 is the same as the rotational speed during the normal suction purge for the purpose of recovering the discharge characteristics of the nozzle 44. are the same.

Note that the liquid in the supply channel 62 may evaporate over time. In this way, when the moisture evaporates, air is generated in the supply channel 62 by the amount of the evaporated moisture. Therefore, air may already exist in the supply channel 62 before the start of the introduction process. In addition, the liquid stirring efficiency during the stirring process improves as the amount of air remaining in the supply channel 62 (connection corner portion 90) increases. Therefore, in this introduction process, the control device 100 controls the air already existing in the supply channel 62 in addition to the trapped air for the purpose of improving the liquid stirring efficiency during the stirring process. The suction pump 11 may be controlled to remain at the portion 90 . Specifically, in this introduction process, the control device 100 slows down the rotational speed of the suction pump 11 (weakens the suction force) compared to the normal suction purge so that the air stays at the connecting corner portion 90 . However, if the rotation speed of the suction pump 11 is slowed down in this way, the processing time required to discharge the above-described total amount of liquid to the outside of the supply flow path 62 becomes longer. Therefore, in this introduction process, if it is desired to shorten the processing time of the introduction process, the suction pump 11 is driven at the same rotation speed as the normal suction purge, and if it is desired to improve the stirring efficiency of the liquid during the stirring process, It is preferable to drive the suction pump 11 at a rotation speed slower than that for normal suction purge.

After finishing the introduction process, the control device 100 repeats N times the stirring process and the discharge process as a set.

In the agitating process, the control device 100 first controls the carriage drive motor 20 to move the head 5 to the origin position facing the flushing receiver 30 from above and below, as shown in FIG. 7(a). Thereafter, the control device 100 controls the carriage drive motor 20 to reciprocate the head 5 together with the carriage 3 in the scanning direction (see FIGS. 7A and 7B).
As a result, force (energy) is applied to the liquid in the in-head channel 80 to cause the liquid to flow, and the liquid in the in-head channel 80 is agitated.

Here, the moving operation of the carriage 3 in the scanning direction is divided into three operations, ie, an accelerating operation, a constant speed operation, and a decelerating operation, in relation to the moving speed of the carriage 3 . The constant-speed operation is an operation for moving the carriage 3 at a constant speed, and is used, for example, when recording an image in which ink is ejected from the head 5 toward the paper P. FIG. On the other hand, the acceleration operation is employed, for example, when accelerating the stopped carriage 3 to a predetermined speed, and the deceleration operation is employed, for example, when stopping the carriage 3 traveling at the predetermined speed. It is an action that

A large force (energy) is applied to the liquid in the in-head channel 80 when the carriage 3 is accelerated or decelerated. Therefore, in this embodiment, during the forward movement, as shown in FIG. 7C, the carriage 3 is accelerated from the origin position to a predetermined speed (the maximum speed of the carriage 3 in this embodiment). Immediately after that, a deceleration operation is performed to stop the carriage 3 at the turn-around position (see FIG. 7(b)). Similarly, during the return movement, the carriage 3 is accelerated from the turnaround position to the above-described predetermined speed, and immediately thereafter decelerated to return the carriage 3 to the origin position. By operating the carriage 3 as described above, the moving distance of the forward movement of the carriage 3 and the moving distance of the backward movement of the carriage 3 can be the same. can be made to coincide with the origin position. Also, as will be described later, the discharging process executed after each stirring process is flushing for discharging ink from the plurality of nozzles 44 of the head 5 toward the flushing receiver 30 . Therefore, by setting the position of the head 5 at the end of each stirring process to the origin position where the head 5 faces the flushing receiver 30, the processing time required for the replacement process can be shortened. As described above, in the present embodiment, the liquid in the in-head channel 80 can be agitated only by controlling the carriage 3 which is an existing configuration of the printer 1 . In addition, in FIGS. 7A and 7B, for convenience of explanation, the configuration of the printer 1 that is not related to the stirring process is omitted.

After finishing the stirring process, the control device 100 executes a discharge process for discharging the liquid stirred by the stirring process in the in-head flow path 80 from the nozzles 44 . During this discharge process, the liquid in the in-head channel 80 is in a state of being stirred by the stirring process. Ejection becomes possible.

By the way, if air remains in a predetermined channel portion in the head internal channel 80 during each agitation process, the presence of this air causes the liquid to flow more in the vicinity of the predetermined channel portion than in the case where no air exists. easier to flow. As a result, when there is air in the predetermined flow path portion, the liquid in the head flow path 80 is agitated. As described above, during the first stirring process, the connection corner between the main flow channel 70 and the connecting flow channel 75, which is a predetermined flow channel portion in the head internal flow channel 80 where the liquid tends to stay, is caused by the introduction process. Since the air remains at 90, the efficiency of agitating the liquid in the vicinity of this connection corner 90 is high. In addition, it is preferable that the air stays at the connecting corner portion 90 in consideration of the stirring efficiency for the second and subsequent stirring processes as well. In addition, after the agitation process and the discharge process are repeated N times, the exhaust process for exhausting the air in the in-head flow path 80 is executed. there's no need to. Therefore, in the present embodiment, the control device 100 controls the piezoelectric actuator 34 in each discharge process to execute flushing for discharging the liquid in the in-head flow path 80 from the nozzles 44 .

In this way, each discharging process is performed by flushing in which the flow of liquid generated in the in-head channel 80 is relatively small. It becomes possible to retain air in the part. As a result, it is possible to improve the stirring efficiency of the liquid in the in-head channel 80 during each stirring process. In addition, since flushing makes it easier to control (adjust) the amount of liquid discharged than suction purge, it suppresses the amount of liquid larger than the set discharge amount from being discharged from the in-head channel 80 in each discharge process. be able to. As a result, the amount of ink consumed during the discharge process can be reduced.

Further, in the present embodiment, the set discharge amount set in each discharge process is a liquid amount corresponding to the volume of the lower flow path 77 in the connection flow path 75 . The lower flow path 77 has a smaller flow path cross-sectional area than the upper flow path 76 and is a flow path in which air is less likely to stagnate. For this reason, in the lower channel 77, the stirring of the liquid in the stirring process does not progress as compared to the upper channel 76, and the storage liquid existing in the lower channel 77 is mainly used in the channel during the discharging process. It will be expelled by the flow of liquid inside. Therefore, by setting the set discharge amount in each discharge process to the amount of liquid corresponding to the volume of the lower channel 77, a large amount of the storage liquid existing in the lower channel 77 can be discharged to the outside of the lower channel 77. can be done. As a result, it is possible to efficiently reduce the storage liquid remaining in the in-head flow path 80 after the replacement process while reducing the amount of ink discharged during the replacement process.

As described above, by repeating the stirring process and the discharging process N times, the amount (concentration) of the storage liquid existing in the head internal flow path 80 can be gradually reduced. The storage solution remaining in the inner channel 80 can be reliably reduced. The number N of repetitions of this stirring process and discharge process is the number of times necessary to reduce the color difference between the ink stored in the ink cartridge 42 and the liquid ejected from the nozzles 44 of the inkjet head 5 to less than a predetermined value. , which is set in advance by experiments, simulations, or the like.

After repeating the stirring process and the discharging process N times, the control device 100 controls the cap unit 9 and the suction pump 11 to exhaust the air in the in-head channel 80 to the outside of the in-head channel 80. Perform exhaust processing. Specifically, in the exhaust process, the control device 100 executes the suction purge. In the suction purge in the exhaust process, the suction force of the suction pump 11 is made stronger than in the suction purge in the introduction process, thereby forcibly discharging the air present in the in-head flow path 80 from the nozzles 44 together with the liquid. That is, the suction force of the suction pump 11 is increased so that the air in the supply channel 62 also passes through the filter 49 and is discharged from the nozzle 44 . As a result, it is possible to prevent deterioration of the ink ejection characteristics of the head 5 due to the air present in the in-head flow path 80 .

(Inkjet printer operation)
Next, an example of the processing operation of the printer 1 when the power of the printer 1 is turned on by the user will be described with reference to FIG.

When the printer 1 is turned on by the user (S1), the CPU 101 determines whether the ink cartridge 42 is attached to the cartridge attachment portion 41 based on the detection result from the sensor 41b (S2). If the CPU 101 determines that the ink cartridge 42 is not attached to the cartridge attachment portion 41 (S2: NO), the CPU 101 causes the display 99 to display a screen prompting the attachment of the ink cartridge 42 to the cartridge attachment portion 41 ( S3), returning to the processing of S2.

On the other hand, if it is determined that the ink cartridge 42 is attached to the cartridge attachment portion 41 (S2: YES), the CPU 101 refers to the RAM 103 to determine the head internal flow of the head 5 mounted on the carriage 3. It is determined whether or not ink has been introduced into the path 80 (whether or not the head is new) (S4). Specifically, the RAM 103 stores an introduction flag indicating whether or not ink has been introduced into the in-head channel 80 . When the introduction flag is ON, the CPU 101 determines that ink has been introduced into the in-head channel 80 and that no storage liquid exists in the in-head channel 80 . On the other hand, when the introduction flag is off, ink has not been introduced into the in-head channel 80 (not introduced), and it is determined that the storage liquid exists in the in-head channel 80 .

If it is determined that the ink has not been introduced into the in-head channel 80 of the head 5 (the storage liquid is present) (S5: YES), the CPU 101 determines to execute the replacement process. By controlling the unit 9 and the suction pump 11 to discharge at least part of the storage liquid in the head internal flow channel 80 to the outside of the head internal flow channel 80, the ink in the ink cartridge 42 is discharged into the entire ink flow channel 85. An introduction process to introduce is executed (S6).

Next, the CPU 101 controls the carriage 3 to move the head 5 in the scanning direction, thereby executing a stirring process of stirring the liquid in the in-head channel 80 (S7). Next, the CPU 101 controls the piezoelectric actuator 34 to perform flushing, thereby executing a discharge process for discharging the liquid stirred by the stirring process in the in-head flow path 80 from the nozzle 44 (S8).

Next, the CPU 101 determines whether or not the number of repetitions of the stirring process and the discharging process has reached N (S9). If it is determined that the number of times has not reached N (S9: NO), the process returns to S7. On the other hand, when it is determined that the number of times has reached N (S9: YES), the CPU 101 controls the cap unit 9 and the suction pump 11 to perform a suction purge, thereby removing the air in the in-head channel 80. is forcibly discharged from the nozzle 44 (S10). After that, the CPU 101 switches the introduction flag stored in the RAM 103 from OFF to ON (S11), and terminates this processing operation.

On the other hand, if it is determined in the process of S4 that ink has been introduced into the in-head channel 80 of the head 5 (S5: NO), the CPU 101 executes the exhaust purge and the suction purge in this order (S12). ). This exhaust purge and suction purge reduce the amount of air present in the head internal flow path 80 and discharge foreign matter, air bubbles, ink that has become highly viscous due to drying, and the like in the head 5 from the nozzle 44 . is recovered. The operation of the printer 1 has been described above.

As described above, according to the present embodiment, in the replacement process, the storage liquid existing in the in-head channel 80 is discharged after being mixed with the ink. It is also possible to discharge the storage liquid existing in the inside head channel 80 to the outside. As a result, the storage liquid remaining in the in-head channel 80 can be reduced. In addition, in this embodiment, the storage liquid can be efficiently discharged during the replacement process, so the amount of ink consumed in the replacement process can be reduced. As a result, it is possible to increase the number of sheets of paper P on which images can be recorded by using the ink cartridge 42 attached to the printer 1 . Further, in the replacement process, the agitation process and the discharge process are repeated a plurality of times as a set, so that the storage liquid existing in the in-head channel 80 can be reliably reduced.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. For example, in the above-described embodiment, flushing is used as the discharging process, but suction purging may be used instead. In this case, the control device 100 makes the control contents of the suction purging executed in the discharge process and the exhaust process different from each other. Specifically, as described above, in the discharge process, the suction force of the suction pump 11 is weakened because it is not necessary to discharge the air present in the in-head channel 80 . As a result, it is possible to suppress excessive discharge of the liquid in the in-head flow path 80 in the discharge process. On the other hand, in the exhaust process, the suction force of the suction pump 11 is made stronger than in the exhaust process. As a result, it becomes possible to reliably exhaust the air present in the in-head flow path 80 .

Further, in the above-described embodiment, the control device 100 performs suction so that at least part of the air in all the ink flow paths 85 stays at the connection corner 90 between the main flow path 70 and the connection flow path 75 in the introduction process. Although the pump 11 is controlled, the flow path portion for retaining air is not limited to this. For example, in the introduction process, the control device 100 may control the suction pump 11 so that the air stays in the damper chamber 71 where the liquid tends to stay.

Also, the control of the control device 100 for retaining air in a predetermined flow path portion during the introduction process is not essential. In this case, since there is a possibility that air is not retained in the predetermined channel portion of the in-head channel 80 during the agitation process, and the agitation in the in-head channel 80 does not proceed, the agitation process and the discharge process are not performed. It is necessary to increase the number of repetitions or to increase the amount of liquid discharged to the outside of the in-head channel 80 during each discharge process. Further, in this case, if the air in the head internal flow path 80 is reduced to such an extent that it does not affect the ejection failure due to the exhaust purge during the introduction process, it is necessary to perform the exhaust process in the replacement process. no. Alternatively, the exhaust process may be performed by the above-described exhaust purge that causes the air in the supply flow path 62 to be exhausted from the exhaust section 23 via the exhaust flow path 74 . In this case, the air can be discharged out of the supply channel 62 with a weaker suction force than when the air in the supply channel 62 is discharged from the nozzle 44 by suction purge.

In the above-described embodiment, the control device 100 is configured to repeat the agitation process and the discharge process as a set in the replacement process a plurality of times. It may be configured to run only once.

Further, as shown in FIG. 9 , in addition to the head 5 , a moving mechanism 4 that moves the head 5 in a direction different from the scanning direction may be provided on the carriage 3 . The moving mechanism 4 includes two guide rails 91, 92, two pulleys 93, 94, a driving belt 95, and a head moving motor 96 (see FIG. 10). The guide rails 91 and 92 are provided on the carriage 3 and extend in the front-rear direction. The head 5 is detachably attached to these two guide rails 91 and 92 and is movable in the front-rear direction along the guide rails 91 and 92 .

The two pulleys 93 and 94 are spaced apart from each other in the front-rear direction on the carriage 3 . Also, the pulley 93 is connected to a head moving motor 96 . The drive belt 95 is an endless belt wound around the two pulleys 93 and 94 . When the pulley 93 is rotationally driven by the head moving motor 96, the driving belt 95 runs, thereby reciprocating the head 5 in the front-rear direction. As described above, in this modification, the head 5 reciprocates in the scanning direction together with the carriage 3 by driving the carriage drive motor 20, and reciprocates in the front-rear direction by driving the head movement motor 96. .

Then, in the stirring process, the control device 100 controls the moving mechanism 4 when the head 5 reciprocates in the scanning direction as shown in FIGS. It is moved in the front-rear direction different from the scanning direction. The movement of the head 5 in the back-and-forth direction may be performed while the head 5 is moving in the scanning direction, or immediately after the head 5 moves in the scanning direction. liquid is in motion.
In this way, by moving the head 5 not only in the scanning direction but also in the front-rear direction, it is possible to further improve the stirring efficiency of the liquid in the in-head channel 80 . The moving direction of the head 5 by the moving mechanism 4 is not limited to the front-rear direction, and may be any direction different from the left-right direction (scanning direction).

Further, in the above-described embodiment, the liquid in the in-head channel 80 is agitated by moving the head 5, but the invention is not particularly limited to this. For example, a stirring blade is arranged in the head channel 80, and the stirring blade is rotationally driven by a motor to cause the liquid to flow in the head channel 80, thereby stirring the liquid. good too.

Also, the flushing receiver 30 is not essential, and the nozzle cap 25 may be configured to receive the liquid discharged from the nozzle 44 during flushing. Further, at the time of shipment, it is not necessary that all the flow paths of the head internal flow path 80 are filled with the storage liquid. It does not have to be filled.

Also, the exhaust passage 74 for performing exhaust purge is not essential. However, if there is no exhaust flow path 74, all the air existing in the damper chamber 71 and the like must be removed from the nozzle 44 at the end of the in-head flow path 80 only by suction purge during the replacement process.

In the above-described embodiment, the ejection liquid introduced into the in-head flow path 80 of the head 5 is ink, but the present invention is not particularly limited to this. It may be a treatment liquid that causes The treatment liquid includes, for example, a treatment liquid that aggregates or precipitates components in the ink.

Further, in the above-described embodiment, all the ink channels 85 are supplied with ink from the ink cartridges 42 detachably attached to the cartridge mounting portion 41. A tank attached to the printer 1 is connected, and ink may be supplied from this tank. When the ink in the tank runs out, the user inserts a bottle containing ink into a refill hole formed in the tank to refill the tank with ink from the bottle.
The present invention can also be applied to a so-called on-carriage type printer in which a cartridge mounting portion for mounting an ink cartridge is mounted on a carriage.
In addition, in the above-described embodiments, the tank, which is the ink supply source, is an ink cartridge. may be The ink containing bag is provided with a cap to which the ink supply tube 22 can be connected, and when the ink supply tube 22 is connected to this cap, the ink in the ink containing bag can flow to the ink supply tube 22. . When the ink supply tube 22 is connected to the cap, air enters the ink supply tube 22. Therefore, the control device 100 stops the air at the connecting corner 90 or the like in the introduction process of the replacement process. By controlling in such a manner, the liquid stirring efficiency in the stirring process can be improved.

The present invention can also be applied to a so-called line-type inkjet printer that records an image on a sheet conveyed by a conveying mechanism with the inkjet head fixed. In the above-described embodiments, the present invention is applied to an inkjet printer that records images by ejecting ink onto paper. The invention can be applied. For example, the present invention can be applied to a liquid ejecting apparatus that ejects a conductive liquid onto a substrate to form a conductive pattern on the substrate surface.

1 Inkjet printer (an example of a liquid ejection device)
5 inkjet head 34 piezoelectric actuator (energy application unit)
42 ink cartridge (an example of a tank)
44 nozzle 100 control device (control unit)

Claims (7)

a nozzle capable of ejecting at least one of an ejection liquid and a storage liquid different from the ejection liquid; and a liquid flow path communicating with the nozzle and supplying the ejection liquid stored in a tank to the nozzle. a head unit;
a cap portion movable between a position in contact with the head unit and a position away from the head unit so as to cover the nozzle;
a pressure generating section that generates a pressure difference between the liquid channel and the inside of the cap defined by the cap section and the head unit when the cap section is in contact with the head unit;
a moving unit that reciprocates the head unit between a position where the nozzles face the cap and a position where the nozzles do not face the cap;
and a control unit,
The control unit
The pressure generating section is operated in a state where the cap section is in contact with the head unit, the ejection liquid is introduced from the tank into the liquid flow path, and the storage liquid in the liquid flow path is introduced. a first discharge process for discharging out of the liquid flow path;
a second discharging process of positioning the cap portion at a position in contact with the head unit, operating the pressure generating portion, and discharging the liquid in the liquid channel to the outside of the liquid channel;
a moving process of reciprocating the head unit a plurality of times by the moving section after the first discharging process and before the second discharging process. . the tank is a cartridge,
2. The liquid ejecting apparatus according to claim 1, wherein the moving section has a carriage on which the head unit and the cartridge are arranged. the tank includes a first cartridge and a second cartridge;
The liquid flow path includes a first liquid flow path for supplying the ejection liquid stored in the first cartridge to the nozzle, and a liquid flow path for supplying the ejection liquid stored in the second cartridge to the nozzle. and a second liquid flow path of
3. The liquid ejecting apparatus according to claim 2, wherein the controller starts the first discharge process after the first cartridge and the second cartridge are mounted. The control unit
An ejection process for ejecting at least one of an ejection liquid and a storage liquid different from the ejection liquid from the nozzle after the first ejection process and before the second ejection process. Item 4. The liquid ejecting apparatus according to any one of items 3. the moving process includes a first reciprocating movement and a second reciprocating movement;
The control unit
5. The liquid ejecting apparatus according to claim 4, wherein the ejecting process is performed between the first reciprocating movement and the second reciprocating movement. The control unit
6. The liquid ejecting apparatus according to claim 4, wherein the ejecting process is performed a plurality of times after the first ejecting process and before the second ejecting process. The control unit
7. The liquid ejecting apparatus according to claim 4, wherein the ejection process is performed at a position where the head unit faces the cap.

Images