JP5790861B2 - Liquid ejecting apparatus and liquid circulation method - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus and a liquid circulation method.

Conventionally, a liquid ejecting apparatus that ejects liquid such as ink from a liquid ejecting head, disposes liquid droplets on a recording medium, and records characters, images, and the like is known.
Here, in Patent Document 1, in order to stably eject a liquid from a liquid ejecting head, a liquid that circulates the liquid between the liquid ejecting head and a tank that stores the liquid supplied to the liquid ejecting head is disclosed. An injection device is disclosed.

  The liquid ejecting apparatus disclosed in Patent Literature 1 includes a main tank that accommodates liquid supplied to the liquid ejecting head as a tank that accommodates liquid, and a sub tank provided between the liquid ejecting head and the main tank. have. In addition, a first circulation channel is provided between the liquid jet head and the sub tank, and a second circulation channel is provided between the sub tank and the main tank.

Since the liquid ejecting apparatus ejects liquid from the liquid ejecting head, the liquid stored in the liquid ejecting head is consumed. When the liquid in the liquid ejecting head is insufficient, proper ejection of the liquid cannot be maintained. Therefore, the liquid is supplied from the sub tank to the liquid ejecting head via the first circulation flow path, and the liquid necessary for the ejection is always held in the liquid ejecting head, so that stable liquid ejection from the liquid ejecting head is performed. Secured.
As described above, since the main object of the invention disclosed in Patent Document 1 is to maintain a stable supply of liquid to the liquid jet head, the flow rate of the second circulation channel is the first circulation flow. The flow rate is almost the same as the road.

JP 2005-28675 A

  By the way, the liquid used in the liquid ejecting apparatus contains a pigment, and when the flow of the liquid is stopped for a predetermined time, the pigment in the liquid settles. However, the amount of liquid stored in the liquid ejecting head is small, and the liquid in the liquid ejecting head is substantially replaced within a predetermined time by circulation through the first circulation flow path. There was little possibility of occurrence.

  However, the amount of liquid stored in the main tank and the sub tank is much larger than the amount of liquid in the liquid jet head, and the flow rate of the second circulation channel is substantially the same as the flow rate of the first circulation channel. For this reason, it is difficult to replace all the liquid in the tank within a predetermined time, and there is a possibility that the sedimentation of the pigment occurs in the tank. When such precipitation of the pigment occurs, the properties of the liquid ejected from the liquid ejecting head may become non-uniform, and the recording quality on the recording medium may become unstable.

  This invention is made in view of such a situation, Comprising: It aims at providing the liquid injection apparatus and liquid circulation method which can suppress sedimentation of the pigment in the liquid in the accommodating part which accommodates the liquid. .

In order to solve the above problems, the present invention employs the following means.
The liquid ejecting apparatus of the present invention is provided between a liquid ejecting head that ejects a liquid containing a pigment, a main tank that stores the liquid supplied to the liquid ejecting head, and the liquid ejecting head and the main tank. A liquid ejecting apparatus having a sub-tank for storing the liquid, wherein the liquid is circulated between the liquid ejecting head and the sub-tank, and between the sub-tank and the main tank. A second circulation channel for circulating the liquid, and a ratio of the flow rate of the second circulation channel to the flow rate of the first circulation channel is set in the main tank with respect to the amount of liquid in the liquid ejecting head. When the amount of liquid in the main tank is less than the amount of liquid in the sub-tank, the ratio of the flow rate of the second circulation channel to the flow rate of the first circulation channel is set. A construction is adopted to reduce than the ratio of the above liquid volume ratio in the main tank with respect to the amount of liquid in the liquid ejecting head.
In the present invention employing such a configuration, the ratio of the flow rate of the second circulation flow path to the flow rate of the first circulation flow path is equal to or higher than the ratio of the liquid amount in the sub tank to the liquid amount in the liquid jet head. Replacement of the liquid stored in the sub tank and the main tank is promoted.

In the liquid ejecting apparatus according to the aspect of the invention, the ratio of the flow rate of the second circulation channel to the flow rate of the first circulation channel is greater than or equal to the ratio of the liquid amount in the main tank to the liquid amount in the liquid ejecting head. Is adopted.
In the present invention employing such a configuration, the ratio of the flow rate of the second circulation flow path to the flow rate of the first circulation flow path is greater than or equal to the ratio of the liquid amount in the main tank to the liquid amount in the liquid jet head. The replacement of the liquid stored in the sub tank and the main tank is promoted.

The liquid ejecting apparatus of the present invention employs a configuration that includes a detection unit that detects the amount of liquid in the main tank and a control unit that controls the flow rate of the second circulation channel based on the detection result of the detection unit. To do.
In the present invention employing such a configuration, for example, when the amount of liquid in the main tank is large, the liquid stored in the sub tank and the main tank can be replaced by increasing the flow rate of the second circulation passage. Further promoted.

The liquid ejecting apparatus of the present invention employs a configuration in which the flow rate of the first circulation channel is a flow rate that forms a pressure at which the liquid is not ejected from the liquid ejecting head.
In the present invention adopting such a configuration, even when the liquid is circulated in the first circulation channel, the liquid is not ejected or leaked from the liquid ejecting head.

In addition, the present invention implements a first circulation step of circulating the liquid between a liquid ejecting head that ejects a liquid containing a pigment and a sub tank that accommodates the liquid, and a main that accommodates the sub tank and the liquid. A liquid circulation method for carrying out a second circulation step for circulating the liquid to and from a tank, wherein in the second circulation step, a ratio of a circulation flow rate of the second circulation step to a circulation flow rate of the first circulation step. When the liquid is circulated at a circulation flow rate that is equal to or higher than the ratio of the liquid amount in the main tank to the liquid amount in the liquid ejecting head, and the liquid amount in the main tank is smaller than the liquid amount in the sub tank Is a ratio in which the ratio of the circulation flow rate of the second circulation step to the circulation flow rate of the first circulation step is equal to or greater than the ratio of the liquid amount in the main tank to the liquid amount in the liquid jet head. To adopt a method of reducing.
In the present invention employing such a method, in the second circulation step, the ratio of the circulation flow rate in the second circulation step to the circulation flow rate in the first circulation step is equal to the liquid amount in the sub-tank with respect to the liquid amount in the liquid ejecting head. Since the liquid circulates at a circulation flow rate equal to or higher than the ratio, replacement of the liquid stored in the sub tank and the main tank is promoted.

According to the present invention, in the second circulation step, the ratio of the circulation flow rate in the second circulation step to the circulation flow rate in the first circulation step is equal to or higher than the ratio of the liquid amount in the main tank to the liquid amount in the liquid ejecting head. A method of circulating the liquid at a circulation flow rate is adopted.
In the present invention employing such a method, in the second circulation step, the ratio of the circulation flow rate in the second circulation step to the circulation flow rate in the first circulation step is the amount of liquid in the main tank with respect to the amount of liquid in the liquid ejecting head. Since the liquid circulates at a circulation flow rate equal to or higher than the ratio, the replacement of the liquid stored in the sub tank and the main tank is promoted.

Further, the present invention employs a method including a detection step of detecting the amount of liquid in the main tank and an adjustment step of adjusting the circulation flow rate of the second circulation step based on the detection result in the detection step.
In the present invention employing such a method, for example, when the amount of liquid in the main tank is large, the liquid stored in the sub tank and the main tank can be replaced by increasing the circulation flow rate in the second circulation step. Further promoted.

In the first circulation step, the liquid is circulated at a circulation flow rate that forms a pressure at which the liquid is not ejected from the liquid ejecting head.
In the present invention employing such a method, even if the liquid circulates in the first circulation step, the liquid does not eject or leak from the liquid ejecting head.

1 is an overall configuration diagram of a printer 1. FIG. 2 is a schematic diagram of an ink supply system 5. FIG.

Hereinafter, an embodiment of the liquid ejecting apparatus of the present invention will be described with reference to FIGS. 1 and 2. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.
In the present embodiment, as a liquid ejecting apparatus, an ink jet printer (hereinafter simply referred to as a “printer”) that records and prints characters, images, and the like by ejecting ink (liquid) containing pigment onto a recording medium such as paper. ").

FIG. 1 is an overall configuration diagram of a printer 1 according to the present embodiment.
A printer (liquid ejecting apparatus) 1 ejects and arranges ink (liquid) containing a pigment on paper or the like, which is a recording medium, and records characters, images, and the like. The printer 1 includes a printer main body 2, a carriage drive system 3, a platen 4, an ink supply system 5, and a capping unit 6.

The printer main body 2 is a member that extends in the left-right direction in FIG. 1 and serves as a base of the printer 1, and is provided with a carriage drive system 3 and the like. In the following, the left-right direction in FIG. 1 is simply referred to as “left-right direction”.
The carriage drive system 3 is a drive system for moving a carriage 32 described later, and includes a guide 31, a carriage 32, a motor 33, a drive pulley 34, a driven pulley 35, and a drive belt 36. Yes.

The guide 31 is a pair of members provided on the printer main body 2 and extending in the left-right direction.
The carriage 32 is a member on which a later-described ejection head 51 and a sub tank 53 are installed, and is provided on a pair of guides 31 so as to be movable in the left-right direction.
The motor 33 is an electric motor that is provided in the printer main body 2 and moves the carriage 32. The drive pulley 34 is integrally connected to the rotation shaft of the motor 33 and winds the drive belt 36. The driven pulley 35 is rotatably provided in the printer body 2 and winds the drive belt 36.

  The drive belt 36 is wound around the drive pulley 34 and the driven pulley 35, and moves the carriage 32 in the left-right direction by driving the motor 33. The drive belt 36 is integrally connected to the carriage 32 at a predetermined location. That is, by driving the motor 33, the drive pulley 34 rotates, and the drive belt 36 wound around the drive pulley 34 moves so as to circulate in a predetermined direction. Since the carriage 32 is integrally connected to the drive belt 36, the carriage 32 is moved by the movement of the drive belt 36.

  The platen 4 is a support member for supporting paper or the like as a recording medium in a flat state. The printer main body 2 is provided with a transport unit (not shown), and the recording medium is transported on the platen 4 by the operation of the transport unit.

  The ink supply system 5 includes an ejection head (liquid ejection head) 51, a main tank 52, a sub tank 53, a first circulation channel 54 (see FIG. 2), a first pump 55 (see FIG. 2), It has 2 circulation flow paths 56, the 2nd pump 57, and the control part 58 (refer FIG. 2). In addition, description of the 1st circulation flow path 54, the 1st pump 55, and the control part 58 is mentioned later.

  The ejecting head 51 ejects ink from a plurality of nozzles 51a (see FIG. 2) to land ink droplets on a recording medium, and is disposed on the lower surface of the carriage 32 so as to face the platen 4. .

The main tank 52 is a replaceable storage unit that is installed in the printer main body 2 and stores ink supplied to the ejection head 51.
The sub tank 53 stores a predetermined amount of ink and is installed on the upper surface of the carriage 32 in order to maintain a stable supply of ink to the ejection head 51 when the main tank 52 is replaced, for example.

The second circulation channel 56 is a channel for circulating and flowing ink between the main tank 52 and the sub tank 53. The second circulation channel 56 is provided between the main tank 52 and the sub tank 53, and includes a supply side tube 56A and a reflux side tube 56B.
The supply side tube 56A and the reflux side tube 56B are both tubular members formed using a flexible material (for example, an elastomer).

  The second pump 57 is a pump for causing ink to flow from the main tank 52 toward the sub tank 53, and is provided between the main tank 52 and the supply side tube 56A.

Next, the ink supply system 5 will be described in more detail with reference to FIG.
FIG. 2 is a schematic diagram of the ink supply system 5 in the present embodiment.

  The ejection head 51 includes a plurality of nozzles 51 a that eject ink, a liquid reservoir 51 b that stores ink, and a piezoelectric element (not illustrated) that is provided in each of the plurality of nozzles 51 a and vibrates when a drive signal is applied. ing.

The maximum amount of ink stored in the main tank 52 is approximately 100 times the amount of liquid in the liquid reservoir 51 b in the ejection head 51.
The main tank 52 is provided with a detection unit 59 that detects the amount of liquid in the main tank 52. The detection unit 59 is electrically connected to the control unit 58 in order to output the detection result to the control unit 58 described later. The detecting unit 59 measures the weight of the main tank 52 to detect the amount of liquid in the main tank 52 and counts the amount of ink ejected from the ejection head 51 to detect the amount of liquid in the main tank 52. Equipment to be used is used.

  The amount of ink stored in the sub tank 53 is approximately 10 times the amount of liquid in the liquid reservoir 51 b in the ejection head 51.

  The first circulation channel 54 is a channel for circulating and flowing ink between the ejection head 51 and the sub tank 53. The first circulation channel 54 is provided between the ejection head 51 and the sub tank 53, and includes a supply side channel 54A and a reflux side channel 54B.

  The first pump 55 is a pump for causing ink to flow from the sub tank 53 toward the ejection head 51, and is provided in the supply side flow path 54 </ b> A.

  The control unit 58 is for controlling the operations of the first pump 55 and the second pump 57. The controller 58 is electrically connected to these pumps 55 and 57 in order to output operation signals to the first pump 55 and the second pump 57. The control unit 58 is configured to control the operation of the second pump 57 based on the detection result of the detection unit 59 and to control the flow rate of ink in the supply side tube 56A.

  The flow rate of the supply side tube 56A is set to at least 10 times the flow rate of the supply side flow channel 54A. That is, the flow rate of the supply side tube 56A is such that the ratio of the flow rate of the supply side tube 56A to the flow rate of the supply side flow path 54A is equal to or higher than the ratio of the liquid amount of the sub tank 53 to the liquid amount of the liquid reservoir 51b in the ejection head 51. The flow rate is set.

  Next, the operation of the printer 1 in this embodiment will be described. Since the present invention is characterized by the ink supply system 5, the overall operation of the printer 1 is omitted, and the operation of the ink supply system 5 will be described in detail below.

  The first pump 55 is operated by an instruction from the control unit 58, and ink flows from the sub tank 53 toward the ejection head 51 in the supply side flow path 54 </ b> A. At the same time, the second pump 57 is actuated by an instruction from the control unit 58, and ink flows in the supply side tube 56A from the main tank 52 toward the sub tank 53. Note that the first pump 55 and the second pump 57 are operating both during the ejection operation and when the printer 1 is stopped.

  During the ejection operation of the printer 1, the piezoelectric element (not shown) of the ejection head 51 is driven, so that the ink stored in the liquid reservoir 51 b is ejected as droplets from the nozzle 51 a, and is landed on the recording medium and characters. And images. Therefore, ink in the liquid reservoir 51b is consumed by ejecting ink from the ejection head 51.

Here, since the first pump 55 causes the ink to flow from the sub tank 53 toward the ejection head 51, the ink is replenished in the liquid reservoir 51b. Accordingly, there is no shortage of ink in the liquid reservoir 51b, and stable ink ejection from the ejection head 51 is ensured.
Incidentally, the flow rate of the ink in the supply-side flow path 54 </ b> A due to the operation of the first pump 55 is set to be larger than the amount consumed by the ejection head 51 ejecting ink. Therefore, the amount of ink supplied to the ejection head 51 exceeds the consumption amount, and the excess ink flows from the ejection head 51 toward the sub tank 53 via the reflux side flow path 54B. That is, the ink circulates and flows in the first circulation channel 54 (first circulation step).

  As the ink circulates in the first circulation flow path 54 in this way, the ink in the liquid reservoir 51b can be substantially replaced before the ink pigment settled in the liquid reservoir 51b starts to settle. it can. Therefore, sedimentation of the ink pigment in the liquid reservoir 51b of the ejection head 51 can be prevented.

  The first pump 55 causes the ink to flow toward the ejection head 51, thereby increasing the pressure in the liquid reservoir 51b. If the pressure is too high, ink may be ejected and leaked from the nozzle 51a without driving the piezoelectric element. Therefore, the flow rate of the ink in the first circulation channel 54 is set to a flow rate that forms a pressure at which the ink is not ejected from the nozzle 51 a of the ejection head 51. Therefore, no ink leaks from the nozzle 51a.

On the other hand, as described above, the second pump 57 is also operated together with the operation of the first pump 55.
The operation of the second pump 57 causes ink to flow from the main tank 52 toward the sub tank 53. Here, the flow rate of the supply side tube 56A is set to at least 10 times the flow rate of the supply side flow channel 54A.
Therefore, the amount of ink supplied to the sub tank 53 exceeds the amount of ink discharged from the sub tank 53, and the excess ink flows from the sub tank 53 toward the main tank 52 via the reflux side tube 56B. To flow. That is, the ink circulates and flows in the second circulation channel 56 (second circulation step).

  Further, the flow rate of the first circulation channel 54 depends on the flow rate of the supply side channel 54A, and the flow rate of the second circulation channel 56 depends on the flow rate of the supply side tube 56A. The flow rate is 10 times or more the flow rate of the first circulation channel 54. That is, the ink in the second circulation channel 56 has a ratio of the flow rate of the second circulation channel 56 to the flow rate of the first circulation channel 54 such that the liquid in the sub tank 53 with respect to the liquid amount of the liquid reservoir 51 b in the ejection head 51. Circulate at a flow rate that is greater than the ratio of the quantities.

  As described above, the amount of liquid in the subtank 53 is about 10 times the amount of liquid in the liquid reservoir 51b, but the flow rate of the second circulation channel 56 flows at a flow rate 10 times or more that of the first circulation channel 54. Therefore, the ink in the sub tank 53 can be substantially replaced before the ink pigment starts to settle in the sub tank 53. Accordingly, the ink pigment can be prevented from settling in the sub tank 53. Furthermore, when the flow rate of the second circulation channel 56 is set to be 100 times or more the flow rate of the first circulation channel 54, that is, the ratio of the flow rate of the second circulation channel 56 to the flow rate of the first circulation channel 54 is When the ratio of the liquid amount in the main tank 52 to the liquid amount in the liquid reservoir 51b in the ejection head 51 is greater than or equal to the ratio, the ink in the main tank 52 can be replaced quickly because the flow rate in the second circulation channel 56 has increased. As a result, sedimentation of the ink pigment in the main tank 52 can be suppressed.

Further, the control unit 58 controls and adjusts the flow rate of the second circulation channel 56 based on the detection result of the detection unit 59.
First, the detection unit 59 detects the amount of liquid in the main tank 52 (detection step), and outputs the detection result to the control unit 58. Based on the detection result, the control unit 58 controls the operation of the second pump 57 and adjusts the flow rate of the second circulation channel 56 (adjustment process).

  The amount of liquid in the sub tank 53 does not vary greatly, but the amount of liquid in the main tank 52 gradually decreases as it is consumed. Therefore, the flow rate of the second circulation path may be decreased as the amount of liquid in the main tank 52 decreases. By doing so, the amount of operation of the second pump can be reduced, and the durability of the flow path of the second circulation path can be improved. Here, when the amount of liquid in the main tank 52 is smaller than the amount of liquid in the sub-tank 53, the flow rate may be set in a ratio with the amount of liquid in the sub-tank 53.

Therefore, according to the present embodiment, the following effects can be obtained.
According to the present embodiment, there is an effect that it is possible to suppress sedimentation of the pigment of the ink stored in the ink supply system 5, particularly the ejection head 51, the sub tank 53, and the main tank 52.

  As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

For example, in the above-described embodiment, an ink jet printer and an ink cartridge are employed, but a liquid ejecting apparatus that ejects or ejects liquid other than ink and a liquid container that accommodates the liquid are employed. May be. The present invention can be used for various liquid ejecting apparatuses including a liquid ejecting head that ejects a minute amount of liquid droplets. In addition, a droplet means the state of the liquid discharged from the said liquid ejecting apparatus, and shall also include what pulls a tail in granular shape, tear shape, and thread shape. In addition, the liquid here may be a material that can be ejected by the liquid ejecting apparatus. For example, it may be in the state when the substance is in a liquid phase, and may be in a liquid state with high or low viscosity, sol, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals (metal melts) ) And a liquid as one state of the substance, as well as particles in which functional material particles made of solid materials such as pigments and metal particles are dissolved, dispersed or mixed in a solvent. In addition, typical examples of the liquid include ink and liquid crystal as described in the above embodiments. Here, the ink includes general water-based inks and oil-based inks, and various liquid compositions such as gel inks and hot-melt inks.
As a specific example of the liquid ejecting apparatus, for example, a liquid containing a material such as an electrode material or a coloring material used for manufacturing a liquid crystal display, an EL (electroluminescence) display, a surface emitting display, a color filter, or the like in a dispersed or dissolved state. It may be a liquid ejecting apparatus for ejecting, a liquid ejecting apparatus for ejecting a bio-organic material used for biochip manufacturing, a liquid ejecting apparatus for ejecting a liquid as a sample used as a precision pipette, a textile printing apparatus, a microdispenser, or the like. In addition, transparent resin liquids such as UV curable resin to form liquid injection devices that pinpoint lubricant oil onto precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. A liquid ejecting apparatus that ejects a liquid onto the substrate or a liquid ejecting apparatus that ejects an etching solution such as an acid or an alkali to etch the substrate may be employed. The present invention can be applied to any one of these ejecting apparatuses and liquid containers.

  In the above embodiment, ink is used as the liquid ejected by the ejection head 51 onto the recording medium. However, the present invention is not limited to this, and is a functional liquid in which metal fine particles are dispersed in a solvent. May be. In other words, the present invention may be applied to an apparatus for forming metal wiring or the like by discharging and arranging the functional liquid on a substrate.

  In the above embodiment, the detection unit 59 is used. However, the present invention is not limited to this, and the ink flows in the second circulation channel 56 at a predetermined flow rate without using the detection unit 59. Alternatively, the control unit 58 may control the second pump 57.

  Moreover, in the said embodiment, although the 1st pump 55 and the 2nd pump 57 are each provided in the supply side flow path 54A and the supply side tube 56A, they may be provided in the recirculation side flow path 54B and the recirculation side tube 56B, respectively. Good. Moreover, as long as the liquid of the 1st circulation flow path 54 and the 2nd circulation flow path 56 can be circulated, you may provide in places other than those.

  DESCRIPTION OF SYMBOLS 1 ... Printer, 51 ... Ejection head, 52 ... Main tank, 53 ... Sub tank, 54 ... 1st circulation flow path, 56 ... 2nd circulation flow path, 58 ... Control part, 59 ... Detection part.

Claims (6)

A liquid ejecting head that ejects a liquid containing a pigment; a main tank that accommodates the liquid supplied to the liquid ejecting head; and a sub-tank that is provided between the liquid ejecting head and the main tank and accommodates the liquid. A liquid ejecting apparatus comprising:
A first circulation channel for circulating the liquid between the liquid jet head and the sub tank;
A second circulation channel for circulating the liquid between the sub-tank and the main tank;
The ratio of the flow rate of the second circulation channel to the flow rate of the first circulation channel is equal to or higher than the ratio of the liquid amount in the main tank to the liquid amount in the liquid ejecting head,
The liquid ejecting apparatus according to claim 1, wherein the flow rate of the second circulation passage is reduced as the amount of liquid in the main tank decreases. The liquid ejecting apparatus according to claim 1 ,
A detector for detecting the amount of liquid in the main tank;
And a control unit that controls a flow rate of the second circulation channel based on a detection result of the detection unit. The liquid ejecting apparatus according to claim 1 or 2 ,
The liquid ejecting apparatus according to claim 1, wherein the flow rate of the first circulation channel is a flow rate that forms a pressure at which the liquid is not ejected from the liquid ejecting head. Performing a first circulation step of circulating the liquid between a liquid ejecting head that ejects a liquid containing a pigment and a sub tank that stores the liquid, and between the sub tank and the main tank that stores the liquid A liquid circulation method for performing a second circulation step of circulating a liquid,
In the second circulation step, the ratio of the circulation flow rate of the second circulation step to the circulation flow rate of the first circulation step is equal to or higher than the ratio of the liquid amount in the main tank to the liquid amount in the liquid ejecting head. Circulating the liquid at a flow rate;
A liquid circulation method , wherein the flow rate of the second circulation passage is decreased as the amount of liquid in the main tank decreases. The liquid circulation method according to claim 4 , wherein
A detection step of detecting the amount of liquid in the main tank;
A liquid circulation method comprising: an adjustment step of adjusting a circulation flow rate of the second circulation step based on a detection result in the detection step. In the liquid circulation method according to claim 4 or 5 ,
In the first circulation step, the liquid is circulated at a circulation flow rate that forms a pressure at which the liquid is not ejected from the liquid ejecting head.

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