Recording apparatus and control method

Abstract

To provide a technique capable of preventing nozzles with discharge failure.SOLUTION: As a decompression threshold being a decompression value applied to a first liquid chamber when applying liquid to recording means having a second liquid chamber communicating with the first liquid chamber through a filter, a value in which the expansion volume of the air does not exceed the volume of the first liquid chamber when the air in a predetermined region where the air is present in a supply flow path for supplying the liquid to the recording means in a circulation path, and a first flow path for communicating the first liquid chamber with the atmosphere when liquid is extracted from the recording means in the circulation path is expanded by decompression, and in which liquid can be filled into the recording means is used.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a recording apparatus and a method for controlling the recording apparatus. [Background technology]

[0002] In a recording device equipped with a recording head that ejects ink from nozzles, if the ejection characteristics cannot be restored even after performing maintenance procedures to maintain and restore good ink ejection characteristics from the nozzles, the recording head is replaced. When replacing the recording head, the ink is drained from the recording head to be replaced, and the recording head is then removed and a new recording head is installed. After that, ink is filled into the new recording head.

[0003] Patent document 1 discloses a technology for filling ink into a recording head by closing an on-off valve provided in an ink supply flow path, reducing the pressure in a liquid chamber in the recording head to a predetermined level, and then opening the on-off valve. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-248792 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the technology of Patent Document 1 is used, when filling a replaced print head with ink, there is a risk of bubbles forming inside the replaced print head due to ink remaining at the connection between the ink supply channel and the print head when the ink is removed from the old print head. Such bubbles can then remain in the nozzles of the print head filled with ink, preventing ink from being ejected properly during the first ejection, which could increase the number of nozzles that experience initial non-ejection (ejection failure).

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to provide a technique capable of suppressing the occurrence of nozzles that exhibit ejection defects. [Means for solving the problem]

[0007] In order to achieve the above object, one embodiment of a recording apparatus according to the present invention comprises a recording means including a first liquid chamber for storing liquid, and a second liquid chamber that is in communication with the first liquid chamber via a filter and stores liquid transferred from the first liquid chamber, and from which the stored liquid is ejected via a nozzle; a circulation path to which the recording means is detachable, which supplies liquid to the first liquid chamber of the attached recording means while recovering liquid from the second liquid chamber, and which can circulate the liquid; a pressure reducing means which can reduce the pressure in the first liquid chamber and the second liquid chamber via the nozzle for the recording means attached to the circulation path; and a pressure reducing means which controls the pressure reducing means to reduce the pressure in the circulation path when the circulation path is not filled with liquid. and a control means for reducing the pressure in the first liquid chamber to a pressure reduction threshold via the nozzle for the attached recording means, thereby causing liquid to flow into the first liquid chamber from the supply flow path of the circulation path, wherein the circulation path branches off at the supply flow path that supplies liquid to the recording means and includes a first flow path that can connect the first liquid chamber to the atmosphere when liquid is extracted from the removed recording means, and the pressure reduction threshold is a value that, when air in a predetermined area in the supply flow path and the first flow path expands due to pressure reduction by the pressure reduction means, the volume of the expanded air does not exceed the volume of the first liquid chamber, and is capable of filling the recording means with liquid. [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress the occurrence of nozzles that exhibit ejection defects. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a recording apparatus. [Figure 2] FIG. 2 is a block diagram showing the control configuration of the printing apparatus. [Figure 3]FIG. [Figure 4] FIG. 4 is a schematic diagram of a flow path configuration in a maintenance unit. [Figure 5] 10 is a flowchart showing the processing contents of a sampling process. [Figure 6] 10A and 10B are diagrams showing the ink extraction state in the extraction process. [Figure 7] 10 is a flowchart showing the processing contents of a filling process. [Figure 8] 5A and 5B are diagrams showing the ink filling state during the filling process. [Figure 9] FIG. 10 is a diagram showing calculated values ​​of a pressure reduction threshold value. [Figure 10] FIG. 10 is a schematic diagram illustrating the configuration of a circulation path in a printing apparatus according to another embodiment. [Figure 11] FIG. 10 is a diagram showing calculated values ​​of a pressure reduction threshold in another embodiment. [Figure 12] 10A to 10C are diagrams showing the results of an experiment conducted by the inventors of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an example of an embodiment of a recording apparatus and a control method will be described with reference to the accompanying drawings. Note that the following embodiment does not limit the present invention, and not all of the combinations of features described in the embodiment are necessarily essential to the solution of the present invention. Furthermore, the positions, shapes, etc. of the components described in the embodiment are merely examples, and are not intended to limit the present invention to only those.

[0011] (First embodiment) First, a recording apparatus according to a first embodiment will be described with reference to FIGS.

[0012] <Configuration of recording device> Fig. 1 is a schematic diagram of a recording device according to this embodiment. The recording device 10 in Fig. 1 is a recording device that conveys a long sheet-like recording medium (hereinafter referred to as "sheet") unwound from a roll and records on the sheet.

[0013] The recording device 10 includes an unwinding roll unit 12 that holds a roll R, a transport path 14 that transports a sheet unwound from the roll R held by the unwinding roll unit 12, and a take-up roll unit 16 that winds up the sheet transported along the transport path 14. The recording device 10 also includes a recording unit 18 that records on the transported sheet, a first drying unit 20 and a second drying unit 22 that dry the sheet after recording, and a cooling unit 24 that cools the sheet after drying. The recording device 10 also includes a maintenance unit 26 that can perform maintenance processing on a recording head 30 (described below) of the recording unit 18 to maintain and restore good ink ejection characteristics, and a control unit 28 that controls the overall operation of the recording device 10.

[0014] The unwinding roll unit 12 is configured to be able to unwind the held roll R and supply a sheet. In FIG. 1, the unwinding roll unit 12 is shown as holding one roll R, but this is not limited thereto. The unwinding roll unit 12 may be configured to hold multiple rolls R and selectively unwind one of the rolls R to supply a sheet. In this case, the multiple rolls R may be, for example, the same type of rolls R, or different types of rolls R.

[0015] The recording unit 18 includes a recording head 30 that can eject ink onto a sheet transported along a transport path 14 (shown by a solid line in FIG. 1 ). The recording head 30 is a line-type recording head in which multiple nozzles that eject ink are arranged in a width direction of the sheet, which intersects with the sheet transport direction. A plurality of recording heads 30 are arranged in parallel along the sheet transport direction. In this embodiment, each recording head 30 is configured to eject different inks and reaction liquids. Specifically, the recording unit 18 includes a recording head that ejects yellow (Ye) ink, a recording head that ejects magenta (Ma) ink, a recording head that ejects cyan (Cy) ink, and a recording head that ejects black (Bk) ink. The recording unit 18 also includes a recording head that ejects reaction liquid (Pri) that reacts with each ink and promotes solidification (hardening) of the ink. That is, in this embodiment, the recording unit 18 is configured to eject five liquids: Ye ink, Ma ink, Cy ink, Bk ink, and reaction liquid. In this specification, the ink and reaction liquid ejected from the recording head 30 will be referred to as "liquid" where appropriate.

[0016] The types and number of liquids that can be ejected by the recording unit 18 are not limited to the five liquids described above. For example, the recording unit 18 may be provided with a recording head 30 capable of ejecting ink of a specific color, such as red (Re), orange (Or), or green (Gr). Alternatively, the recording unit 18 may be provided with a recording head 30 capable of ejecting a treatment liquid that performs a predetermined treatment on the ink ejected onto the sheet. Each recording head 30 is configured to eject ink using an inkjet system. As the inkjet system, various known systems can be used, such as a system using a heat generating element, a system using a piezoelectric element, a system using an electrostatic element, or a system using a MEMS element. Each recording head 30 is supplied with ink (reaction liquid) via a corresponding circulation path 300 (described below). A tank storing the corresponding type of ink (reaction liquid) is connected to this circulation path 300, and the ink (reaction liquid) is supplied from the tank.

[0017] The first drying section 20 and the second drying section 22 are configured to heat the sheet after recording by the recording section 18 and dry the ink (reaction liquid) applied to the sheet. The first drying section 20 and the second drying section 22 reduce the liquid component contained in the ink (reaction liquid) applied to the sheet, improving the fixation of the ink to the sheet. The second drying section 22 is located downstream of the first drying section 20 in the sheet conveyance direction. The first drying section 20 and the second drying section 22 are configured to blow hot air onto at least the ink-applied side of the conveyed sheet to raise the temperature of the sheet. Note that the drying method used in the first drying section 20 and the second drying section 22 is not limited to the method of blowing hot air. Various known drying methods, such as a method of irradiating the ink-applied surface of the sheet with electromagnetic waves (such as ultraviolet or infrared rays) or a conductive heat transfer method using contact with a heating element, may be used, or a combination of multiple drying methods may be used.

[0018] The cooling unit 24 is configured to be able to cool the sheet. As a result, the cooling unit 24 cools the sheet heated in the first drying unit 20 and the second drying unit 22, and solidifies the ink softened by the temperature increase in the first drying unit 20 and the second drying unit 22. Furthermore, cooling by the cooling unit 24 suppresses the amount of temperature change of the sheet on the subsequent conveyance path 14. The cooling unit 24 is configured to cool the sheet by blowing air at a temperature lower than that of the sheet heated in the first drying unit 20 and the second drying unit 22 onto at least the ink-applied side of the conveyed sheet. The cooling method used by the cooling unit 24 is not limited to the air blowing method, and various known cooling methods, such as a heat conduction method using contact with a heat dissipation member, may be used, or a combination of multiple cooling methods may be used.

[0019] The winding roll unit 16 is configured to be able to wind up onto the core 16a a sheet that has been recorded by the recording unit 18, processed in the first drying unit 20, the second drying unit 22, and the cooling unit 24, and then transported. Hereinafter, the series of processes in which the sheet wound from the unwinding roll unit 12 is recorded by the recording unit 18, processed in the first drying unit 20, the second drying unit 22, and the cooling unit 24, and then wound onto the winding roll unit 16 will be appropriately referred to as the recording process. In FIG. 1, the winding roll unit 16 is configured to wind up the sheet onto a single core 16a, but this is not limited thereto. The winding roll unit 16 may also have multiple cores and be configured to selectively wind up the sheet. Note that in the recording device 10, the winding roll unit 16 winds up the sheet onto the core 16a after recording, but this is not limited thereto. For example, a cutter for cutting the sheet may be provided, and instead of the winding roll unit 16, a stacking unit for stacking the sheets cut by the cutter may be provided.

[0020] The maintenance unit 26 includes a cap unit 32 that protects the nozzle surface of the recording head 30 on which the nozzles are formed, and a cleaning unit 34 that maintains and restores the ejection performance of each nozzle. The cleaning unit 34 is configured to, for example, suck and wipe off any deposits on the nozzle surface. Known technologies can be used to configure the cleaning unit 34, and detailed descriptions thereof are omitted. The maintenance unit 26 is located upstream of the recording unit 18 in the sheet transport direction (left-right direction in FIG. 1 ) and is configured to be able to move back and forth from one side to the other and from the other side to the other side in the sheet transport direction. When not performing maintenance processing, the maintenance unit 26 is located in a standby position (position shown in FIG. 1 ). When performing maintenance processing on each recording head 30 of the recording unit 18, the maintenance unit 26 lifts the recording head 30 and then moves from the standby position to a maintenance position facing the recording head 30. The maintenance unit 26 then performs maintenance processing on the recording head 30 in the maintenance position, i.e., capping with the cap unit 32 and wiping with the cleaning unit 34.

[0021] The control unit 28 is connected to a host device 36 such as a host computer via an external interface, etc. This allows the recording device 10 to be controlled by the host device 36. The control unit 28 is equipped with an operation unit 206 (described later) through which the user inputs and outputs data.

[0022] <Control configuration of recording device> Next, we will explain the control configuration of the recording device 10. Figure 2 is a block diagram showing the control configuration of the recording device 10.

[0023] The recording device 10 comprises a print engine unit 200 that controls the recording mechanism, mainly including the recording section 18, and a control section 28 that controls the entire recording device 10. A print controller 222 controls various mechanisms of the print engine unit 200 according to instructions from a main controller 202 of the control section 28. The control configuration will be described in detail below.

[0024] In the control unit 28, a main controller 202 configured by a CPU controls the entire recording device 10 using a RAM 210 as a work area in accordance with programs and various parameters stored in a ROM 212. For example, when a recording job is input from the host device 36 via a host I / F 204, an image processing unit 214 performs image processing on the received image data in accordance with instructions from the main controller 202. The main controller 202 then transmits the image data that has undergone image processing to the print engine unit 200 via a print engine I / F 208.

[0025] The recording device 10 may acquire image data from the host device 36 via wireless or wired communication, or may acquire image data from an external storage device (not shown) such as a USB memory connected to the recording device 10. The communication method used for wireless or wired communication is not limited. For example, Wi-Fi (registered trademark) or Bluetooth (registered trademark) can be used as a communication method for wireless communication. Furthermore, USB or the like can be used as a communication method for wired communication.

[0026] The operation unit 206 is a mechanism that allows the user to input and output data to and from the recording device 10. The user can set the recording mode and view information about the recording device 10 via the operation unit 206.

[0027] In the print engine unit 200, a print controller 222 configured by a CPU controls various components of the recording mechanism, including the recording unit 18, in accordance with programs and various parameters stored in a ROM 224, using a RAM 226 as a work area. When various commands and image data are received via a controller I / F 220, the print controller 222 temporarily stores them in the RAM 226. Then, the print controller 222 causes an image processing controller 228 to convert the stored image data into recording data so that the recording head 30 can use it for recording operations. Once the recording data is generated, the print controller 222 causes the recording head 30 to perform a recording operation based on the recording data via a head I / F 238.

[0028] At this time, the print controller 222 drives the unwinding roll unit 12, the winding roll unit 16, and the transport rollers provided on the transport path 14 via the transport control unit 236 to transport the sheet unwound from the roll R. Then, in accordance with instructions from the print controller 222, the recording head 30 performs a recording operation in conjunction with the sheet transport operation, and the sheet undergoes processing in the first drying unit 20, the second drying unit 22, the cooling unit 24, and the like, before being subjected to recording processing on the sheet.

[0029] The movement control unit 234 controls the recording head 30 so that it can move up and down between a recording position (the position shown in FIG. 1) at startup and a processing position at maintenance. At the processing position, a space is created below the recording head 30 in which the maintenance unit 26 can be positioned. At the recording position, the distance between the recording head 30 and the sheet becomes a preset distance suitable for recording.

[0030] The supply control unit 230 controls each component of the circulation path 300 (described later) so as to keep the pressure of the ink supplied to the recording head 30 within an appropriate range and to execute the extraction process and filling process (described later). The maintenance control unit 232 controls each component of the maintenance unit 26 and controls the operation of the maintenance unit 26 when performing the maintenance process, extraction process, and filling process on the recording head 30.

[0031] <Circulation route configuration> Next, the circulation paths of the ink and reaction liquid provided in the recording apparatus 10 will be described. Fig. 3 is a diagram showing the circulation paths of the ink and reaction liquid provided in the recording apparatus 10. The circulation path 300 shown in Fig. 3 is provided for one recording head 30, and in this embodiment, the circulation path 300 shown in Fig. 3 is provided for each of the five recording heads 30. In the following explanation, the circulation path that supplies ink to the recording head 30 and recovers ink from the recording head 30 will be described, but the circulation path for the reaction liquid has a similar configuration.

[0032] In the recording device 10, the recording head 30 and a buffer tank 302 that stores ink are connected by a supply flow path 304 and a recovery flow path 306 to form a circulation path 300 that allows ink to circulate between the recording head 30 and the buffer tank 302. The circulation path 300 is also provided with a relief flow path 308, one end of which is connected to a joint portion 307 that is a connection portion with the recording head 30 in the supply flow path 304, and the other end of which is connected to the buffer tank 302. The circulation path 300 is further provided with a branch flow path 309 (hereinafter also referred to as a "first flow path") that branches off from the supply flow path 304 near the joint portion 307. In the recording device 10, the recording head 30 is detachable from the circulation path 300.

[0033] In the supply flow path 304, a supply pump 310, a filter 312, and a valve 314 are arranged in this order from the buffer tank 302 side toward the print head 30 side. The supply pump 310 is driven to transfer ink from the buffer tank 302 to the print head 30. The filter 312 is configured to remove impurities that have become mixed in with the ink passing through it. The valve 305 can be opened and closed to control the restriction and permission of the supply of ink from the supply flow path 304. That is, by opening the valve 305, the supply of ink from the buffer tank 302 to the print head 30 is permitted, and by closing the valve 305, the supply is restricted.

[0034] The print head 30 includes a first liquid chamber 316 connected to a supply flow path 304 and a second liquid chamber 318 connected to a recovery flow path 306. When these two liquid chambers are filled with ink supplied from the supply flow path 304, ink can be ejected from a nozzle 320 that communicates with the second liquid chamber 318. The first liquid chamber 316 and the second liquid chamber 318 communicate with each other via a filter 322, which removes impurities from the liquid transferred from the first liquid chamber 316 to the second liquid chamber 318. This prevents the occurrence of nozzles 320 that exhibit ejection defects (or no ejection). The filter 322 may be, for example, a mesh structure with many holes. Thus, in this embodiment, the recording head 30 functions as a recording unit having a first liquid chamber 316 that stores liquid, and a second liquid chamber 318 that is connected to the first liquid chamber 316 via a filter 322 and from which liquid transferred from the first liquid chamber 316 is ejected via a nozzle.

[0035] The recovery flow path 306 is provided with a recovery pump 324 that can transfer ink in the second liquid chamber 318 of the print head 30 to the buffer tank 302. This allows the circulation path 300 to recover ink that has not been ejected from the print head 30 to the buffer tank 302. By driving the supply pump 310 and the recovery pump 324, the ink in the buffer tank 302 is recovered into the buffer tank 302 via the supply flow path 304, the print head 30, and the recovery flow path 306 in that order, allowing the ink to be circulated in the circulation path 300. In FIG. 3, the direction in which ink circulates in the circulation path 300 is indicated by solid arrows along each flow path. Note that when the recovery pump 324 is not driven, ink is not transferred (moved) in the recovery flow path 306.

[0036] A relief valve 328 is provided in the relief flow path 308 (hereinafter also referred to as the "third flow path") near a junction 326 with the supply flow path 304. The relief valve 328 is a differential pressure valve that releases the liquid delivery pressure from the supply pump 310 to the relief flow path 308 in order to keep the supply pressure applied to the recording head 30 constant when the supply pump 310 is driven to supply ink to the recording head 30. The relief valve 328 is not configured to be opened and closed by a drive mechanism, but is spring-biased, and is configured to open when a predetermined pressure is reached.

[0037] For example, when the amount of ink supplied per unit time from the supply pump 310 is greater than the sum of the amount of ink ejected per unit time from the print head 30 and the amount of ink recovered per unit time from the recovery pump 324, the relief valve 328 opens in accordance with the pressure acting on it. This forms a circulating flow path consisting of a part of the supply flow path 304, the relief flow path 308, and the buffer tank 302. As described above, in this embodiment, the relief flow path 308 is configured to allow liquid to flow in from the supply flow path 304 when the supply pressure of ink (reaction liquid) to the print head 30 increases. By providing the relief flow path 308, the amount of ink supplied to the print head 30 is adjusted in accordance with the amount of ink consumed by the print head 30, and the pressure in the circulation path 300 can be stabilized regardless of image data.

[0038] Branch flow path 309 branches off from supply flow path 304 at branch portion 330 between junction 326 and joint portion 307 in supply flow path 304. One end of branch flow path 309 is connected to supply flow path 304, and the other end is open. Branch flow path 309 is provided with atmosphere communication valve 332 that connects the inside of branch flow path 309 to the atmosphere when opened, and isolates the inside of branch flow path 309 from the atmosphere when closed.

[0039] <Flow path configuration of the maintenance section> Next, we will explain the flow path configuration in the maintenance unit 26. Figure 4 is a schematic diagram of the flow path configuration in the maintenance unit 26.

[0040] In addition to the cap section 32 and the cleaning section 34, the maintenance section 26 is equipped with a suction section 400 for generating negative pressure in the cap section 32 and the cleaning section 34, and a recovery section 402 for recovering waste liquid such as ink and reaction liquid sucked by the suction section 400.

[0041] The suction unit 400 is connected to the cap unit 32 and cleaning unit 34 provided for each recording head 30. In Fig. 4, the suction unit 400 connected to the cap unit 32 and cleaning unit 34 corresponding to the recording head 30 that ejects Cy ink is shown, but the suction unit 400 is connected to the cap unit 32 and cleaning unit 34 corresponding to each recording head 30.

[0042] Suction unit 400 includes negative pressure tank 406, the interior of which is controlled to a negative pressure by suction pump 404. Valve 405 is provided between negative pressure tank 406 and suction pump 404, and by opening valve 405 and driving suction pump 404, negative pressure is generated inside negative pressure tank 406. Furthermore, by closing valve 405, negative pressure tank 406 is no longer affected by the driving of suction pump 404.

[0043] The negative pressure tank 406 is connected to the cap unit 32 via a first suction flow path 408 and is connected to the cleaning unit 34 via a second suction flow path 410. A valve 412 is provided in the first suction flow path 408. Opening the valve 412 connects the cap unit 32 to the negative pressure tank 406, and closing the valve 412 blocks communication between the cap unit 32 and the negative pressure tank 406. A pressure gauge 414 is provided in the first suction flow path 408 between the valve 412 and the connection with the cap unit 32. The pressure gauge 414 makes it possible to measure the negative pressure in the suction unit 400. A valve 416 is provided in the second suction flow path 410. Opening the valve 416 connects the cleaning unit 34 to the negative pressure tank 406, and closing the valve 416 blocks communication between the cleaning unit 34 and the negative pressure tank 406.

[0044] With this configuration, the suction unit 400 can generate negative pressure inside the cap unit 32 via the negative pressure tank 406 by driving the suction pump 404. Furthermore, by driving the suction pump 404, it is possible to generate a suction force that sucks the nozzle surface in the cleaning unit 34 via the negative pressure tank 406. Specifically, when generating negative pressure inside the cap unit 32, the suction pump 404 is driven with the valve 412 of the first suction flow path 408 open, the valve 416 of the second suction flow path 410 closed, and the valve 405 open. At this time, the negative pressure generated inside the cap unit 32 can be measured by the pressure gauge 414 provided in the first suction flow path 408. Furthermore, when generating suction force in the cleaning unit 34, the suction pump 404 is driven with the valve 412 of the first suction flow path 408 closed, the valve 416 of the second suction flow path 410 open, and the valve 405 open.

[0045] The recovery unit 402 includes a recovery unit 402a that recovers waste ink and a recovery unit 402b that recovers waste reaction liquid. That is, the recovery unit 402a recovers waste ink from four suction units 400 connected to the cap units 32 and cleaning units 34 that correspond to the recording heads 30 that eject ink. The recovery unit 402b recovers waste reaction liquid from one suction unit 400 connected to the cap units 32 and cleaning units 34 that correspond to the recording heads 30 that eject reaction liquid. By separately providing the recovery unit 402a that recovers waste ink and the recovery unit 402b that recovers waste reaction liquid, it is possible to prevent the waste ink and the waste reaction liquid from reacting with each other in the recovery unit 402, solidifying inside the recovery unit 402, and clogging the flow path.

[0046] The recovery unit 402a includes a drain sub-tank 422 connected to the negative pressure tank 406 of the suction unit 400 via a waste ink flow path 420, and a waste ink tank 424 that stores waste ink. A pump 426 is provided in the waste ink flow path 420, and by driving the pump 426, the waste ink stored in the negative pressure tank 406 is recovered into the drain sub-tank 422 via the waste ink flow path 420. Note that the pump 426 is configured such that the transfer (movement) of waste ink in the waste ink flow path 420 is restricted when the pump 426 is not driven.

[0047] The drain sub-tank 422 and the waste ink tank 424 are connected by a flow path 430 provided with a pump 428, and by driving the pump 428, the waste ink collected in the drain sub-tank 422 is transferred to the waste ink tank 424 via the flow path 430. The waste ink tank 424 is provided with a sensor (not shown) that can detect the amount of storage. When the sensor detects that the amount of waste ink stored in the waste ink tank 424 has reached the upper limit of the amount that can be stored in the waste ink tank 424, the main controller 202 notifies the user via the operation unit 206 to urge them to replace the waste ink tank 424. Note that the amount of waste ink stored in the waste ink tank 424 may be estimated, for example, from the drive amount of the pump 428 without using a sensor.

[0048] The recovery unit 402b includes a drain sub-tank 442 connected to the negative pressure tank 406 of the suction unit 400 via a waste liquid flow path 440, and a waste liquid tank 444 that stores the waste reaction liquid. A pump 446 is provided in the waste liquid flow path 440, and by driving the pump 446, the waste reaction liquid stored in the negative pressure tank 406 is recovered into the drain sub-tank 442 via the waste liquid flow path 440. The pump 446 is configured to restrict the transfer (movement) of waste ink in the waste ink flow path 420 when the pump 446 is not driven.

[0049] The drain sub-tank 442 and the waste liquid tank 444 are connected by a flow path 450 provided with a pump 448, and by driving the pump 448, the waste reaction liquid collected in the drain sub-tank 442 is transferred to the waste liquid tank 444 via the flow path 450. The waste liquid tank 444 is provided with a sensor (not shown) capable of detecting the storage amount. When the sensor detects that the storage amount of the waste reaction liquid in the waste liquid tank 444 has reached the upper limit of the storage amount that can be stored in the waste liquid tank 444, the main controller 202 notifies the user via the operation unit 206 to prompt replacement of the waste liquid tank 444. Note that the storage amount of the waste liquid in the waste liquid tank 444 may be estimated, for example, from the drive amount of the pump 448 without using a sensor.

[0050] <Replacing the recording head> In the above configuration, the recording device 10 replaces the recording head 30 at a predetermined timing, such as when the ejection characteristics of the recording head 30 cannot be restored even after performing maintenance processing. When replacing the recording head 30, the recording device 10 first performs an extraction process to extract the ink (reaction liquid) from the recording head 30 to be replaced, and then the user replaces the recording head 30 from which the ink (reaction liquid) has been extracted with a new recording head 30. The recording device 10 then performs a filling process to fill the interior of the new replaced recording head 30 with ink.

[0051] In such a case of replacing the print head 30, for example, the main controller 202 may take the lead in performing the extraction process as the print head 30 replacement process, then notify the user to replace the print head, and then perform the refilling process. Alternatively, each task may be performed individually as part of the print head 30 replacement work. In this case, for example, the user may instruct the start of the extraction process, and after confirming the completion of the extraction process, the print head 30 may be replaced, and then the user may instruct the start of the refilling process. The extraction process and the refilling process will be described below.

[0052] <Sampling process> First, the extraction process for extracting ink (reaction liquid) from the recording head 30 will be described. This extraction process is executed by the print controller 222 in response to instructions from the main controller 202. FIG. 5 is a flowchart showing the detailed process contents of the extraction process. The series of processes shown in the flowchart in FIG. 5 are performed by the print controller 222 expanding program code stored in the ROM 224 into the RAM 226 and executing it. Alternatively, some or all of the functions of the steps in FIG. 5 may be executed by hardware such as an ASIC or an electric circuit. In this specification, the symbol S in the description of each process in the flowchart indicates a step in that flowchart.

[0053] 6(a) to 6(c) are diagrams showing the ink extraction state corresponding to the open / closed state of the valve and the operating state of the pump during the extraction process. In FIG. 6, an "x" above a valve or pump indicates that the valve is closed, and that the pump is stopped. In FIG. 6, a valve or pump without an "x" above it indicates that the valve is open, and that the pump is operating.

[0054] In this removal process, under the control of the print controller 222 in accordance with the program code, the supply control unit 230 controls each component in the circulation path 300, while the maintenance control unit 232 controls the maintenance unit 26. When there are multiple recording heads 30 that require replacement, the removal process may be performed on each one individually, or may be performed simultaneously on some or all of the recording heads 30 that require replacement.

[0055] When the removal process is started, first, in S502, the print controller 222 caps the recording head 30 with the corresponding cap unit 32. As a result, the nozzle surface of the recording head 30 is protected by the cap unit 32, and the inside of the cap unit 32 is shielded from the outside. Next, in S504, the print controller 222 stops driving the supply pump 310 and the recovery pump 324. As a result, the circulation of the ink (reaction liquid) in the circulation path 300 is stopped.

[0056] Then, in S506, the print controller 222 closes all valves in the circulation path 300. Specifically, it closes valve 314 and atmosphere communication valve 332. Thereafter, in S508, the print controller 222 opens valves 405 and 412 of the suction unit 400 in the maintenance unit 26. Subsequently, in S510, the print controller 222 closes valve 416, and then, in S512, the print controller 222 drives the suction pump 404. At this time, the open / closed states of the valves and the driving states of the pumps in the suction unit 400 and circulation path 300 are as shown in FIG. 6(a).

[0057] Thereafter, in S514, the print controller 222 determines whether the measurement value of the pressure gauge 414 has reached a predetermined value. In this embodiment, the predetermined value is, for example, -70 kPa, but is not limited to this. More specifically, the predetermined value is a pressure value at which ink can be extracted from the print head 30 in the processes of S516 and S518, which will be described later. Therefore, the predetermined value, along with a first time period, which will be described later, is determined experimentally depending on the configuration of the print head 30, the suction unit 400, the circulation path 300, and the like. Note that, in S512, it is determined whether the measurement value of the pressure gauge 414 has reached a predetermined value. However, the present invention is not limited to this. For example, it may be determined whether the operating time of the suction pump 404 has reached a predetermined time.

[0058] If it is determined in S514 that the measured value of the pressure gauge 414 has not reached the predetermined value, the determination in S514 is performed again. If it is determined in S514 that the measured value of the pressure gauge 414 has reached the predetermined value, the process proceeds to S516, where the print controller 222 opens the atmosphere communication valve 332. Then, in S518, the print controller 222 determines whether a first time period has elapsed. The recording device 10 is provided with a counter (not shown) that measures time. When the print controller 222 opens the atmosphere communication valve 332 in S516, the counter starts counting, and begins measuring the elapsed time since the atmosphere communication valve 332 was opened. Note that the counter starts counting after its count value is initialized. Therefore, in S518, it is determined whether the count value of the counter has reached the first time period. In this embodiment, the first time period is, for example, 30 seconds, but is not limited to this.

[0059] Here, when the atmosphere communication valve 332 is opened in S516, the branch flow path 309 is connected to the atmosphere, and air flows in through the branch flow path 309. As a result, the ink in the branch flow path 309, the ink located from the branch portion 330 to the joint portion 307, and the ink located in the print head 30 are sucked into the suction portion 400 via the cap portion 32. The sucked ink is then stored in the negative pressure tank 406 (see FIG. 6(b)). Also, in S518, by continuing the state in which air flows in from the branch flow path 309 for a first time period, ink is extracted from the region S1 from the atmosphere communication valve 332 to the joint portion 307, the first liquid chamber 316, the second liquid chamber 318, and the nozzles 320 of the print head 30. Region S1 (hereinafter also referred to as "predetermined region") is the region from the atmosphere communication valve 332 to the branch portion 330 in the branch flow path 309 and the region from the branch portion 330 to the joint portion 307 in the supply flow path 304 (see FIG. 6(b)). In other words, region S1 is the region where ink is replaced with air when ink is extracted from the recording head 30. Note that unless the supply pump 310 is driven (or the valve 314 is opened), the ink upstream of the branch portion 330 in the supply flow path 304 forms a meniscus at the branch portion 330 and maintains an air-liquid interface.

[0060] Therefore, the first time period is, for example, the time period during which the measurement value of the pressure gauge 414 reaches the predetermined value and ink can be extracted from the first liquid chamber 316 and the second liquid chamber 318 of the print head 30 via the cap unit 32 while the suction pump 404 is operating. The first time period is determined experimentally, for example, according to the predetermined value and the configurations of the print head 30, the suction unit 400, the circulation path 300, etc.

[0061] If it is determined in S518 that the first time has not elapsed, it is determined that the ink (reaction liquid) has not yet been removed from the print head 30, and the determination in S518 is performed again. If it is determined in S518 that the first time has elapsed, it is determined that the ink (reaction liquid) has been removed from the print head 30, and the print controller 222 stops driving the suction pump 404 in S520. At this time, the counting by the counter may be stopped and the count value may be initialized. Then, in S522, the print controller 222 opens the valve 416. Then, in S524, the print controller 222 releases the capping of the print head 30 by the cap unit 32. That is, in S524, the cap unit 32 and the print head 30 are separated. Thereafter, in S526, the print controller 222 drives the recovery pump 324 for a second time, and ends this removal process. The elapse of the second time is based on the count value of a counter (not shown). In this embodiment, the second time period is, for example, 40 seconds, but is not limited to this.

[0062] With the print head 30 and the cap unit 32 separated, driving the recovery pump 324 in S526 causes air to flow into the print head 30 not only from the branch flow path 309 but also from the nozzles 320 (see FIG. 6C). This makes it possible to remove ink remaining in the nozzles 320. Furthermore, by continuing to drive the recovery pump 324 for the second time, the small amount of ink remaining in the second liquid chamber 318 of the print head 30 is also recovered into the buffer tank 302 together with the ink in the recovery flow path 306. Therefore, the second time is set to, for example, a time during which the ink remaining in the second liquid chamber 318 and the ink remaining in the nozzles 320 can be removed by driving the recovery pump 324.

[0063] By performing this extraction process, leakage of ink from the removed print head 30 is suppressed even when the print head 30 is removed from the recording apparatus 10. Furthermore, in the circulation path 300, the ink upstream of the branching portion 330 forms a meniscus and maintains a gas-liquid interface, so leakage of ink from the supply flow path 304 is suppressed even when the print head 30 is removed from the recording apparatus 10. Furthermore, when recovering the ink remaining in the print head 30 from the recovery flow path 306, the recovery pump 324 is continuously driven for only the second time, so leakage of ink from the recovery flow path 306 is also suppressed.

[0064] <Filling process> Next, a filling process for filling ink (reaction liquid) into the recording head 30 will be described. This filling process is executed by the print controller 222 in response to instructions from the main controller 202. FIG. 7 is a flowchart showing the detailed processing contents of the filling process. The series of processes shown in the flowchart in FIG. 7 are performed by the print controller 222 expanding program code stored in the ROM 224 into the RAM 226 and executing it. Alternatively, some or all of the functions of the steps in FIG. 7 may be executed by hardware such as an ASIC or an electric circuit.

[0065] 8(a) and 8(b) are diagrams showing ink filling states corresponding to the open / closed states of the valves and the operating states of the pumps during the filling process. In FIG. 8, an "x" above a valve or pump indicates that the valve is closed, and a pump indicates that the pump is stopped. In FIG. 8, a valve or pump without an "x" above it indicates that the valve is open, and a pump indicates that the pump is operating.

[0066] In this filling process, under the control of the print controller 222 in accordance with the program code, the supply control unit 230 controls each component in the circulation path 300, while the maintenance control unit 232 controls the maintenance unit 26. When multiple recording heads 30 have been replaced, the filling process may be performed on each one one by one, or may be performed simultaneously on some or all of the replaced recording heads 30.

[0067] When the filling process starts, first, in S702, the print controller 222 caps the print head 30 with the corresponding cap unit 32. This protects the nozzle surface of the print head 30 with the cap unit 32, and shields the interior of the cap unit 32 from the outside. Next, in S704, the print controller 222 stops driving the supply pump 310 and the recovery pump 324. Note that, typically, when a user replaces a print head 30, the supply pump 310 and the recovery pump 324 are stopped, and these pumps are also stopped when the filling process, which is executed after the replacement, starts. Therefore, if the supply pump 310 and the recovery pump 324 are stopped when the process of S702 is executed, the process of S704 is omitted.

[0068] Next, in S706, the print controller 222 closes all valves in the circulation path 300. Specifically, it closes valve 314 and atmosphere communication valve 332. Thereafter, in step S708, the print controller 222 opens valves 405 and 412 of the suction unit 400 in the maintenance unit 26. Subsequently, in S710, the print controller 222 closes valve 416, and then, in S712, the print controller 222 drives the suction pump 404.

[0069] At this time, the open / closed states of the valves in the suction unit 400 and the circulation path 300 and the driving states of the pumps are as shown in FIG. 8( a). Furthermore, the driving of the suction pump 404 reduces the pressure in the first liquid chamber 316 and the second liquid chamber 318 in the print head 30 that is not filled with ink. In this manner, in this embodiment, the suction unit 400 (and the cap unit 32) functions as a pressure reducing unit that can reduce the pressure in the first liquid chamber 316 and the second liquid chamber 318 via the nozzle 320 for the print head 30 attached to the circulation path 300. Furthermore, the region S1 is also reduced in pressure via the joint unit 307. However, because the valve 314 is closed and the driving of the supply pump 310 is stopped, a meniscus is formed by the ink upstream of the branching unit 330, maintaining an air-liquid interface. Therefore, the driving of the suction pump 404 in S712 reduces the pressure in the region S1 in the flow path upstream of the print head 30. At the same time, in the recovery flow path 306 downstream of the print head 30, the air in the region S2 (see FIG. 8A) from the recovery pump 324, whose driving is stopped, to the print head 30 is also decompressed.

[0070] Thereafter, in S714, the print controller 222 determines whether the reduced pressure value of the first liquid chamber 316 of the print head 30 has reached a reduced pressure threshold p1. Specifically, in S714, it determines whether the measurement value of the pressure gauge 414 has reached the reduced pressure threshold p1. The reduced pressure threshold p1 will be described later. In this manner, in this embodiment, the pressure gauge 414 functions as a measurement unit capable of measuring the pressure value of the first liquid chamber 316. If it is determined in S714 that the measurement value of the pressure gauge 414 has not reached the reduced pressure threshold p1, the determination of S714 is performed again. Furthermore, if it is determined in S714 that the measurement value of the pressure gauge 414 has reached the reduced pressure threshold p1, the print controller 222 stops driving the suction pump 404 in S716.

[0071] Next, in S718, the print controller 222 drives the supply pump 310. In S720, the print controller 222 opens the valve 314, and then in S722, the print controller 222 determines whether the third time has elapsed. When the valve 314 is opened in S720, a counter (not shown) starts counting, measuring the time since the valve 314 was opened. The counter starts counting after the count value is initialized. In this embodiment, the third time is, for example, 30 seconds, but is not limited to this. The third time is, for example, the time required for ink to be filled into the print head 30 while the supply pump 310 is operating after the measurement value of the pressure gauge 414 reaches the pressure reduction threshold p1. At this time, factors such as the amount of ink filled into the region S2 and the amount of ink suctioned into the negative pressure tank 406 may also be taken into consideration. The third time is determined experimentally, for example, depending on the configuration of the print head 30, the circulation path 300, and the like.

[0072] If it is determined in S722 that the third time has not elapsed, the process returns to S722. If it is determined in S722 that the third time has elapsed, the process proceeds to S724, which will be described later. After the reduced pressure in the first liquid chamber 316 reaches the reduced pressure threshold p1, the valve 314 is opened while the supply pump 310 is driven. After the third time has elapsed, ink fills the print head 30, as shown in FIG. 8B. Specifically, ink located upstream of the branching portion 330 flows into the first liquid chamber 316 and the second liquid chamber 318 of the print head 30, filling them. At this time, ink fills the reduced-pressure region S1, and ink also flows into and fills a portion of the region S2. Since the negative pressure tank 406 is also depressurized, some of the ink filled in the print head 30 flows into the negative pressure tank 406 through the nozzles 320, thereby filling the nozzles 320 with ink. In addition, ink also flows out into a portion of the reduced-pressure region S2.

[0073] In S724, the print controller 222 opens the valve 416 to connect the inside of the negative pressure tank 406 to the atmosphere via the cleaning unit 34. This prevents the ink filled in the liquid chambers in the print head 30 from flowing out of the nozzles 320. Then, in S726, the print controller 222 uncapping the print head 30 with the cap unit 32. That is, in S726, the cap unit 32 and the print head 30 are separated from each other. This opens the inside of the cap unit 32 to the atmosphere. Then, in S728, the print controller 222 re-caps the print head 30 with the cap unit 32, ending this filling process. By re-capping the print head 30 in S728, the nozzles 320 are protected and ink drying in the nozzles 320 is suppressed. After the filling process is completed, it is preferable to drive the pump 426 (446) to recover the ink (reaction liquid) stored in the negative pressure tank 406 into the drain sub-tank 422 (442) via the waste ink flow path 420 (waste liquid flow path 440). In this way, in this embodiment, the print controller 222 functions as a control unit that controls the transfer of ink in the circulation path 300 and the suction unit 400, and reduces the pressure in the first liquid chamber 316 to the pressure reduction threshold via the nozzle 320, thereby filling the recording head 30 with liquid.

[0074] <Decompression threshold p1> Next, the pressure reduction threshold p1 will be described. First, concerns that may arise due to the configuration of the print head 30 and the circulation path 300 will be described.

[0075] =Possible Concerns Due to the Configuration of the Circulation Route 300= As described above, when replacing the recording head 30 in the recording device 10, the ink is extracted from the recording head 30 to be replaced by an extraction process. This extraction process also extracts ink from the region S1, which includes part of the supply flow path 304 and part of the branch flow path 309, but a thin layer of ink remains on the inner wall of this region S1. Over time, this remaining ink moves downward due to its own weight, reaches the joint portion 307, which is the connection portion between the recording head 30 and the supply flow path 304, and forms a liquid film at the joint portion 307.

[0076] When the pressure inside the print head 30, which is not filled with ink, is reduced during the filling process while a liquid film has formed on the joint portion 307, the air in the region S1 expands in volume due to the reduced pressure, and the liquid film is pushed out into the print head 30. At this time, if the volume of the expanded air in the region S1 is greater than the volume of the first liquid chamber 316 of the print head 30, the liquid film passes through the filter 322, causing the liquid film to foam.

[0077] Bubbles generated by passing through the filter 322 tend to remain in the nozzles 320 when they are transferred from the second liquid chamber 318 to the cap portion 32, which increases the number of nozzles 320 that experience initial non-ejection (ejection failure). When the pressure inside the print head 30, which is not filled with ink, is reduced, the air inside the recovery flow path 306 also expands, and the liquid film formed at the connection between the recovery flow path 306 and the print head 30 is also moved to the second liquid chamber 318. However, at this time, the liquid film does not pass through the filter 322, so bubbles are unlikely to be generated.

[0078] =Get decompression threshold p1= Therefore, in this embodiment, in order to prevent the liquid film formed in the joint portion 307 from passing through the filter 322 when the pressure is reduced during the filling process, the pressure reduction threshold p1 is set so that the volume of the expanded air in the region S1 is smaller than the volume of the first liquid chamber 316. Therefore, the pressure reduction threshold p1 is obtained using the volume of the region S1 and the volume of the first liquid chamber 316.

[0079] Specifically, the pressure reduction threshold p1, which is the pressure reduction value of the first liquid chamber 316 (a relative value from the atmospheric pressure P0), is set to satisfy the following formula (1), where V1 is the volume of the first liquid chamber 316 and A is the volume of the region S1. Note that the volume A of the region S1 is the sum of the volume from the atmosphere communication valve 332 to the branch portion 330 in the branch flow path 309 and the volume from the branch portion 330 to the joint portion 307 in the supply flow path 304. |p1|=P0×V1 / (V1+A) (1)

[0080] FIG. 9 is a diagram showing the pressure reduction threshold p1 corresponding to the volume V1 of the first liquid chamber 316, the volume A of the region S1, and the atmospheric pressure P0. FIG. 9 shows the pressure reduction threshold p1 corresponding to the volume V1 and volume A, with the atmospheric pressure P0 set to 101.3 kPa, 90.0 kPa, 80.0 kPa, and 75.0 kPa. The volumes V1, A, and atmospheric pressure P0 shown in FIG. 9 are merely examples. The volume V1 of the first liquid chamber 316 is a characteristic value of the print head 30, and the volume A of the region S1 is a characteristic value of the circulation path 300 in the recording device 10. Therefore, these values ​​are constants. Therefore, the volume ratio V1 / (V1+A) in equation (1) can be calculated from the characteristic values ​​of the print head 30 and the recording device 10 (circulation path 300). Furthermore, the atmospheric pressure P0 in equation (1) is a value that depends on the temperature and altitude of the environment in which the recording device 10 is installed. This atmospheric pressure P0 may be selectable by the user from a number of preset values, or may be measurable or calculable when performing a filling process when replacing the recording head 30 in the installation environment of the recording device 10.

[0081] In the recording device 10, for example, a table showing the volume V1 and volume A (or the volume ratio described above) of the recording device 10 and the pressure reduction threshold p1 corresponding to a plurality of atmospheric pressures P0 may be stored in a storage area such as the ROM 224 of the print engine unit 200. Alternatively, the volume V1 and volume A (or the volume ratio described above) of the recording device 10 may be stored in the storage area, and the pressure reduction threshold p1 may be calculated according to the set (or measured or calculated) atmospheric pressure P0 when the filling process is started.

[0082] =Effect of decompression threshold p1= In the above-described filling process, the suction pump 404 is driven in S712, causing the volume of air in the region S1 to expand, pushing the liquid film formed in the joint portion 307 into the first liquid chamber 316. Then, in S714, when the measured value of the pressure gauge 414 reaches the pressure reduction threshold value p1, the suction pump 404 is stopped, and while the supply pump 310 is driven, the valve 314 is opened for only a third time period, allowing ink to flow into the recording head 30.

[0083] As described above, the volume expansion of the air in region S1 due to the decompression by S712 pushes the liquid film formed in the joint portion 307 into the first liquid chamber 316, but when the measurement value of the pressure gauge 414 reaches the decompression threshold p1, the liquid film has not passed through the filter 322. Therefore, at this timing, the liquid film does not foam as it passes through the filter 322. Then, by flowing ink (reaction liquid) into the recording head 30 at this timing, the occurrence of nozzles 320 with retained bubbles is suppressed when filling the ink (reaction liquid) in the filling process, and the number of nozzles 320 that experience initial non-ejection is reduced.

[0084] <Action and effect> As described above, in the recording device 10, when the pressure inside the recording head 30 is reduced during the filling process, ink (reaction liquid) is allowed to flow into the recording head 30 at the timing when the reduced pressure value in the first liquid chamber 316 reaches the reduced pressure threshold p1. This reduced pressure threshold p1 is set to a value that prevents the liquid film formed in the joint portion 307 from passing through the filter 322 provided between the first liquid chamber 316 and the second liquid chamber 318 when it is pushed into the first liquid chamber 316, depending on the volume of the first liquid chamber and the volume of the region S1.

[0085] This suppresses the generation of bubbles caused by the liquid film passing through the filter 322 at the above timing, and suppresses the occurrence of nozzles 320 where bubbles remain when the ink (reaction liquid) is subsequently filled, thereby making it possible to reduce the number of nozzles 320 that become initially non-ejecting.

[0086] (Second embodiment) Next, a recording device according to a second embodiment will be described with reference to Figures 10 and 11. In the following description, the same reference numerals as those used in the first embodiment will be used to denote components that are the same as or equivalent to those in the recording device according to the first embodiment, and detailed description thereof will be omitted.

[0087] The second embodiment differs from the first embodiment in that a pressure gauge is provided in the branch flow path 309, and whether or not the measurement value of the pressure gauge reaches a pressure reduction threshold value p1 is determined during the filling process. This will be described in detail below.

[0088] <Circulation route configuration> First, a circulation path 1000 provided in the recording apparatus 10 according to this embodiment will be described. Fig. 10 is a diagram showing the circulation path 1000 and the suction unit 400 when the recording head 30 is capped with the cap unit 32 during the filling process. The circulation path 1000 shown in Fig. 10 is provided for one recording head 30, and in this embodiment, a circulation path 1000 shown in Fig. 10 is provided for each of the five recording heads 30. The following description will focus on the differences in the circulation paths 300.

[0089] The circulation path 1000 is provided with a pressure gauge 1004 at a predetermined position P in the branch flow path 309 via a flow path 1002 (hereinafter also referred to as a "second flow path"). As a result, in the recording apparatus 10, the amount of ink supplied to the print head by the relief flow path 308 is adjusted in accordance with the amount of ink consumed by the print head, and the pressure gauge 1004 can be used to check whether the pressure in the circulation path 1000 is stable regardless of image data. Note that in this embodiment, the flow path 1002 provided with the pressure gauge 1004 is formed by branching from the branch flow path 309, but this is not limited to this. For example, the flow path 1002 may be formed by branching from the supply flow path 304 somewhere between the joint portion 307 and the junction portion 326 (the connection portion of the relief flow path 308).

[0090] This pressure gauge 1004 is used in the filling process to determine whether or not the pressure reduction threshold p1 has been reached. That is, in this embodiment, in S714 of the filling process, it is determined whether or not the measurement value of the pressure gauge 1004, not the pressure gauge 414, has reached the pressure reduction threshold p1. In this way, in this embodiment, the pressure gauge 1004 functions as a measurement unit capable of measuring the pressure value of the first liquid chamber 316.

[0091] In the above configuration, when the extraction process is performed, the ink (reaction liquid) in the branch flow path 309 is extracted, but the ink in the flow path 1002 forms a meniscus at the predetermined position P to maintain the gas-liquid interface and does not leak into the branch flow path 309. Also, in the flow path 1002, an air remaining region 1002a where air remains and a liquid remaining region 1002b where ink (reaction liquid) remains are formed.

[0092] Then, in the filling process, when the suction pump 404 is driven in S712 to reduce the pressure inside the print head 30, not only does the volume of the air in the region S1 expand, but the volume of the air in the air remaining region 1002a of the flow path 1002 also expands. For this reason, the volume of the air that pushes the liquid film formed in the joint portion 307 into the first liquid chamber 316 of the print head 30 must also take into account the volume of the air remaining region 1002a.

[0093] <Getting decompression threshold p1> In this embodiment, the pressure reduction threshold p1 is obtained using the volume of region S1, the volume of first liquid chamber 316, and the volume of residual air region 1002a. Specifically, the pressure reduction threshold p1, which is the pressure reduction value of first liquid chamber 316 (a relative value from atmospheric pressure P0), is set to satisfy the following equation (2), where V1 is the volume of first liquid chamber 316, A is the volume of region S1, and Q is the volume of residual air region 1002a. |p1|=P0×V1 / (V1+A+Q) ··· (2)

[0094] 11 is a diagram showing the pressure reduction threshold p1 according to the volume V1 of the first liquid chamber 316, the volume A of the region S1, the volume Q of the residual air region 1002a, and the atmospheric pressure P0. Fig. 11 shows the pressure reduction threshold p1 according to the volume V1, the volume A, and the volume Q for four atmospheric pressures P0 of 101.3 kPa, 90.0 kPa, 80.0 kPa, and 70.0 kPa. Note that the volumes V1, A, Q, and atmospheric pressure P0 shown in Fig. 11 are merely examples.

[0095] The volume V1 of the first liquid chamber 316 is a value specific to the print head 30, and the volume A of the region S1 is a value specific to the circulation path 1000 in the recording device 10, so these values ​​are constants. The volume Q of the air remaining region 1002a is a calculated value calculated when the filling process is performed. Specifically, the volume Q is calculated from the length of the air remaining region 1002a in the extension direction of the flow path 1002 and the diameter of the flow path 1002. The diameter of the flow path 1002 is stored in a storage area such as the ROM 224 of the print engine unit 200. The length of the air remaining region 1002a is set to a value based on the detection result of a detection sensor capable of detecting the length of the flow path 1002, for example. Alternatively, the length of the air remaining region 1002a may be a value obtained in advance and stored in the storage area.

[0096] Therefore, the volume ratio V1 / (V1+A+Q) in the above equation (2) can be calculated from the characteristic values ​​of the print head 30 and the characteristic values ​​of the recording device 10 (circulation path 1000). Furthermore, the atmospheric pressure P0 in the above equation (1) is a value that depends on the temperature and altitude in the installation environment of the recording device 10. This atmospheric pressure P0 may be selectable by the user from a plurality of preset values, or may be measured or calculated when a filling process is performed when replacing the print head 30 in the installation environment of the recording device 10.

[0097] In the recording device 10 according to this embodiment, for example, the storage area may store a table indicating a decompression threshold p1 corresponding to the volume V1 and volume A of the recording device 10, multiple values ​​that the residual air region 1002a can take, and multiple atmospheric pressures P0. Alternatively, the storage area may store the volume V1 and volume A of the recording device 10, and when starting the filling process, the decompression threshold p1 may be calculated according to the calculated volume Q and the set (or measured or calculated) atmospheric pressure P0.

[0098] <Effect of decompression threshold p1> In the above-described filling process, the suction pump 404 is driven in S712, and the volume of the air in the region S1 and the air in the residual air region 1002a expands, pushing the liquid film formed in the joint portion 307 into the first liquid chamber 316. Then, in S714, when the measured value of the pressure gauge 1004 reaches the pressure reduction threshold value p1, the suction pump 404 is stopped, and while the supply pump 310 is driven, the valve 314 is opened to allow ink to flow into the print head 30.

[0099] As described above, the volume expansion of the air in region S1 and residual air region 1002a due to the decompression by S712 pushes the liquid film formed in the joint portion 307 into the first liquid chamber 316. Then, when the measurement value of the pressure gauge 1004 reaches the decompression threshold p1, the liquid film has not passed through the filter 322. Therefore, at this timing, the liquid film does not generate bubbles due to passing through the filter 322. Then, by flowing ink (reaction liquid) into the recording head 30 at this timing, the occurrence of nozzles 320 with accumulated bubbles is suppressed when filling the ink (reaction liquid) in the filling process, and the number of nozzles 320 that experience initial non-ejection is reduced.

[0100] <Action and effect> As described above, in this embodiment, when depressurizing the print head 30 during the filling process, ink is allowed to flow into the print head 30 at the timing when the pressure reduction value in the first liquid chamber 316 reaches the pressure reduction threshold p1, as measured by the pressure gauge 1004. This pressure reduction threshold p1 is set to a value that prevents the liquid film formed in the joint portion 307 from passing through the filter 322 provided between the first and second liquid chambers when it is pushed into the first liquid chamber, depending on the volumes of the first liquid chamber 316, the region S1, and the residual air region 1002a. As a result, the printing apparatus 10 according to this embodiment achieves the same effects as the first embodiment.

[0101] (Experiments conducted by the inventors) Next, an experiment conducted by the present inventor will be described. The present inventor conducted an experiment to verify the state of the print head when a filling process was performed using the technology according to the above-described embodiment. In this experiment, a printing apparatus was used, which was equipped with a print head having a first liquid chamber with a volume V1 of 10.2 cc and a circulation path having a region S1 with a volume A of 2.0 cc. A print head not filled with ink (reaction liquid) after a sampling process was then attached to this printing apparatus, and a filling process was then performed. The filling rate of the second liquid chamber and the number of nozzles that failed to eject initially (the incidence of nozzles that failed to eject initially) were evaluated. The experimental samples were three examples that used the technology according to the above-described embodiment and three comparative examples that did not use this technology. The conditions for each of the three examples and three comparative examples were as follows:

[0102] <Example> In Example 1, the circulation path is not provided with a pressure gauge 1004, and the atmospheric pressure P0 in the environment in which the recording apparatus is installed is set to 101.3 kPa. Therefore, in Example 1, using the above formula (1), |p1| = 101.3 × 10.2 / (10.2 + 2.0) = 84 kPa, and the pressure reduction threshold p1 is set to -84.0 kPa. In this case, the pressure p in the first liquid chamber when the pressure reduction threshold p1 is reached is expressed as P0 - |p1|, or p = 101.3 - 84.0 = 17.3 kPa. In Example 1, in S714 of the filling process, it is determined whether the measured value of the pressure gauge 414 has reached the pressure reduction threshold p1 (-84.0 kPa). In Example 1, the third time in S722 of the filling process is set to 30 seconds.

[0103] In Example 2, a pressure gauge 1004 was provided in the circulation path, and the volume Q of the residual air region 1002a in the flow path 1002 where the pressure gauge 1004 was provided was set to 1.5 cc. The atmospheric pressure P0 in the environment in which the recording apparatus was installed was set to 101.3 kPa. Therefore, in Example 2, using the above formula (2), |p1| = 101.3 × 10.2 / (10.2 + 2.0 + 1.5) = 74.0 kPa, and the pressure reduction threshold p1 was set to -74.0 kPa. In this case, the pressure p in the first liquid chamber when the pressure reduction threshold p1 was reached was p = 101.3 - 74.0 = 27.3 kPa. In Example 2, in S714 of the filling process, it was determined whether the measured value of the pressure gauge 1004 reached the pressure reduction threshold p1 (-74.0 kPa). In Example 2, the third time in S722 of the filling process was set to 30 seconds.

[0104] In Example 3, a pressure gauge 1004 was provided in the circulation path, and the volume Q of the residual air region 1002a in the flow path 1002 where the pressure gauge 1004 was provided was set to 1.5 cc. The atmospheric pressure P0 in the environment in which the recording apparatus was installed was set to 80.0 kPa. Therefore, in Example 3, using the above formula (2), |p1| = 80 × 10.2 / (10.2 + 2.0 + 1.5) = 59.0 kPa, and the pressure reduction threshold p1 was set to -59.0 kPa. In this case, the pressure p in the first liquid chamber when the pressure reduction threshold p1 was reached was p = 80.0 - 59.0 = 21.0 kPa. In Example 3, in S714 of the filling process, it was determined whether the measurement value of the pressure gauge 1004 reached the pressure reduction threshold p1 (-59.0 kPa). In Example 3, the third time in S722 of the filling process was set to 30 seconds.

[0105] <Comparative Example> In Comparative Example 1, the circulation path was not provided with a pressure gauge 1004, and the atmospheric pressure P0 in the environment in which the recording apparatus was installed was set to 101.3 kPa. In Comparative Example 1, the pressure reduction threshold p1 was set to -90.0 kPa, which is lower (i.e., a higher degree of pressure reduction) than -84.0 kPa (the pressure reduction threshold p1 in Example 1). In this case, the pressure p in the first liquid chamber when the pressure reduction threshold p1 was reached was p = 101.3 - 90.0 = 11.3 kPa. In Comparative Example 1, in S714 of the filling process, it was determined whether the measurement value of the pressure gauge 414 had reached the pressure reduction threshold p1 (-90.0 kPa). In Comparative Example 1, the third time in S722 of the filling process was set to 30 seconds.

[0106] In Comparative Example 2, a pressure gauge 1004 was provided in the circulation path, and the volume Q of the residual air region 1002a in the flow path 1002 where the pressure gauge 1004 was provided was set to 1.5 cc. The atmospheric pressure P0 in the environment in which the recording apparatus was installed was set to 101.3 kPa. In Comparative Example 2, the pressure reduction threshold p1 was set to −84.0 kPa, which is lower than −74 kPa (the pressure reduction threshold p1 in Example 2). In this case, the pressure p in the first liquid chamber when the pressure reduction threshold p1 was reached was p = 101.3 − 84.0 = 17.3 kPa. In Comparative Example 2, in S714 of the filling process, it was determined whether the measurement value of the pressure gauge 1004 had reached the pressure reduction threshold p1 (−84.0 kPa). In Comparative Example 2, the third time in S722 of the filling process was set to 30 seconds.

[0107] In Comparative Example 3, a pressure gauge 1004 was provided in the circulation path, and the volume Q of the residual air region 1002a in the flow path 1002 where the pressure gauge 1004 was provided was set to 1.5 cc. The atmospheric pressure in the environment in which the recording apparatus was installed was set to 80.0 kPa. In Comparative Example 3, the pressure reduction threshold p1 was set to −62.7 kPa, which is lower than −59.0 kPa (the pressure reduction threshold p1 in Example 3). In this case, the pressure p in the first liquid chamber when the pressure reduction threshold p1 was reached was p = 80.0 − 62.7 = 17.3 kPa. In Comparative Example 3, in S714 of the filling process, it was determined whether the measurement value of the pressure gauge 1004 reached the pressure reduction threshold p1 (−62.7 kPa). In Comparative Example 3, the third time in S722 of the filling process was set to 30 seconds.

[0108] <Evaluation method> The method for evaluating the filling rate of the second liquid chamber and the number of nozzles that fail to eject initially is as follows.

[0109] = Filling rate of the second liquid chamber = The second liquid chamber is provided with a first electrode and a second electrode, and a third electrode is provided between the first and second electrodes. The three electrodes are arranged in the direction of gravity in the following order: first electrode, third electrode, second electrode. By detecting the voltage value when a weak current flows between the first and second electrodes, it is possible to detect whether the ink level in the second liquid chamber is located below a predetermined vertical position. Specifically, when the ink level in the second liquid chamber is located at the same position as the predetermined vertical position or above that position, a weak current flows through the ink when the two electrodes are passed, and therefore the detected voltage value is lower than the threshold value. On the other hand, when the ink level in the second liquid chamber is located below the predetermined vertical position, no current flows through the ink, and therefore the detected voltage value when a weak current flows is higher than the threshold value.

[0110] If the detected voltage value when a weak current is passed between the first and second electrodes is lower than the threshold value, i.e., the ink level in the second liquid chamber is at or above the predetermined position, the fill rate in the second liquid chamber is deemed "Excellent." If the detected voltage value when a weak current is passed between the first and second electrodes is higher than the threshold value, i.e., the ink level in the second liquid chamber is below the predetermined vertical position, the third electrode is used. Specifically, if a weak current is passed between the third and second electrodes and the detected voltage value is lower than the threshold value, the ink level in the second liquid chamber is near the predetermined position, and the fill rate of the second liquid chamber is deemed "Good." Furthermore, if a weak current is passed between the third and second electrodes and the detected voltage value is higher than the threshold value, the ink level in the second liquid chamber is not near the predetermined position, and the fill rate of the second liquid chamber is deemed "Bad."

[0111] = Number of nozzles with initial non-discharge problems = The number of nozzles that would initially fail to eject ink was evaluated using a predetermined pattern for detecting the number of non-ejecting nozzles. Specifically, a predetermined pattern was recorded during the first recording using the recording head after the filling process, and the number of non-ejecting nozzles, which are nozzles that were not properly ejecting ink (including nozzles that did not eject ink at all), was obtained from the recording results. If the number of non-ejecting nozzles was less than 0.06% of the total number of nozzles in the recording head, it was rated as "Excellent," if it was 0.06% or more but less than 0.1%, it was rated as "Good," and if it was 0.1% or more, it was rated as "Bad." In other words, the number of nozzles that would initially fail to eject ink was evaluated based on the incidence rate of initially non-ejecting nozzles.

[0112] <Experimental Results> The results of this experiment are shown in Figure 12. Figure 12 is a table showing the experimental conditions and results for each sample. In both Example 1 and Example 2, the evaluation result for the filling rate of the second liquid chamber was "Excellent," and the evaluation result for the number of initially non-discharge nozzles was "Excellent." In Example 3, the evaluation result for the filling rate of the second liquid chamber was "Good," and the evaluation result for the number of initially non-discharge nozzles was "Excellent." On the other hand, in all of Comparative Examples 1-3, the evaluation result for the filling rate of the second liquid chamber was "Excellent," but the evaluation result for the number of initially non-discharge nozzles was "Bad."

[0113] In Example 1, which does not include the pressure gauge 1004, the volume expansion of the air in region S1 remains below the volume V1 of the first liquid chamber 316 until the pressure reduction threshold p1 obtained by equation (1) above is reached. Therefore, even when the liquid film formed in the joint portion 307 is pushed into the recording head 30 by the pressure reduction caused by the suction pump 404, it does not pass through the filter 322, and bubbles are not generated by the liquid film passing through the filter 322. This is thought to be why Example 1 received a good evaluation of the number of initial non-ejecting nozzles.

[0114] On the other hand, in Comparative Example 1, which does not include the pressure gauge 1004, the pressure is reduced even further than the pressure reduction threshold p1 in Example 1, so the volumetric expansion of the air in region S1 becomes greater than the volume V1 of the first liquid chamber. As a result, the liquid film formed in the joint portion 307 is pushed into the recording head 30 by the reduced pressure caused by the suction pump 404 and passes through the filter 322, causing bubbles to form. This is thought to be the reason why Comparative Example 1 received a low rating for the number of initial non-ejecting nozzles.

[0115] Furthermore, in Examples 2 and 3, which are equipped with the pressure gauge 1004, the sum of the volumetric expansion of the air in region S1 and the volumetric expansion of the air in residual air region 1002a is less than or equal to the volume V1 of the first liquid chamber 316 until the pressure reduction threshold p1 obtained by equation (2) is reached. Therefore, even when the liquid film formed in the joint portion 307 is pushed into the recording head 30 by the pressure reduction caused by the suction pump 404, it does not pass through the filter 322, and bubbles are not generated by the liquid film passing through the filter 322. This is thought to be why Examples 2 and 3 received good evaluations of the number of initial non-ejecting nozzles.

[0116] On the other hand, in Comparative Examples 2 and 3, which are equipped with a pressure gauge 1004, the pressure is reduced even further than the reduced pressure thresholds in Examples 2 and 3. Therefore, the sum of the volumetric expansion of the air in region S1 and the volumetric expansion of the air in residual air region 1002a is greater than the volume V1 of the first liquid chamber. As a result, the liquid film formed in the joint portion 307 is pushed into the recording head 30 by the reduced pressure caused by the suction pump 404 and passes through the filter 322, generating bubbles. This is thought to be why Comparative Examples 2 and 3 received low ratings for the number of initial non-ejecting nozzles.

[0117] (Other embodiments) The above-described embodiment may be modified as shown in the following (1) to (10).

[0118] (1) Although not specifically described in the above embodiment, the circulation path 300 (1000) may be provided with a degassing module for removing air contained in the ink (reaction liquid) circulating within the circulation path 300 (1000). In this case, the air that expands due to the depressurization by the suction pump 404 is limited to almost only the region S1 (and the air remaining region 1002a), more reliably suppressing the occurrence of the initial number of non-ejecting nozzles. Therefore, in a configuration without a degassing module, the depressurization threshold p1 may be calculated taking into account the air contained in the ink (reaction liquid). In this case, for example, the volume of air contained in the ink (reaction liquid) is added to the denominator of the above equations (1) and (2).

[0119] (2) In the second embodiment, the volume Q of the remaining air region 1002a is calculated from the length of the remaining air region 1002a and the diameter of the flow path 1002. However, this is not limiting and, for example, the volume Q may be predicted from the pressure reduction threshold value at the time of the previous print head replacement. For example, the volume Q of the remaining air region 1002a is set to satisfy the following equation (3), where B is the volume of the flow path 1002 and p2 is the pressure reduction threshold value at the time of the previous print head replacement. Q = B × (P0 - |p2|) / P0 (3)

[0120] The volume Q of the residual air region 1002a calculated by this equation (3) is then substituted into the above equation (2) to calculate the pressure reduction threshold p1. In this case, the pressure reduction threshold p2 at the time of the previous print head replacement (i.e., the pressure reduction threshold used in the most recent filling process) is saved in a storage area such as the ROM 224 of the print engine unit 200. Therefore, when the pressure reduction threshold p1 is calculated by the above equation (2) using the volume Q obtained by the above equation (3) and the filling process is performed, the value of the pressure reduction threshold p2 at the time of the previous print head replacement, which is saved in the storage area, is updated to the value of the calculated pressure reduction threshold p1.

[0121] (3) In the above embodiment, the recording device 10 is configured to record on a sheet unwound from the roll R, but this is not limited to this and may be configured to record on cut sheets such as paper sheets. In this case, a feeding module capable of feeding the topmost cut sheet of cut sheets stacked and stored in a cassette is provided instead of the unwinding roll unit 12. Also, a stacking module capable of stacking discharged cut sheets after recording is provided instead of the winding roll unit 16. The cut sheet supplied from the feeding module is then transported along the transport path 14 and discharged to the stacking module.

[0122] (4) Although not specifically mentioned in the above embodiment, if the determination in the sampling process or filling process continues for more than a certain time, the print controller 222 may determine that an error has occurred and stop the process. In this case, the main controller 202 may notify the user of the error via the operation unit 206 or the like in response to the stop of the process. For example, if the determination in S714 continues for more than a certain time, possible causes include a leak at the contact point between the print head 30 and the cap unit 32 or a pressure loss due to ink bubbling in the first suction channel 408. For this reason, when notifying the user of the error, possible causes of the error may also be notified.

[0123] (5) In the above embodiment, after the recording head 30 is uncapped in S726, the recording head 30 is uncapped again in S728, but this is not limited to this. For example, after the recording head 30 is uncapped in S726, a suction and wiping process may be performed by the cleaning unit 34 to wipe the nozzle surface while sucking it, and then the recording head 30 may be uncapped again. Note that processes for recovering the ink ejection performance of the recording head 30, such as this suction recovery process, may be performed after the filling process is completed.

[0124] (6) Although not specifically mentioned in the first embodiment, the absolute value of the actual pressure reduction value of the first liquid chamber 316 tends to be smaller than the pressure reduction value (measurement value) of the pressure gauge 414. Therefore, depending on the configuration of the suction unit 400, the circulation path 300, the print head 30, etc., the relationship between the measurement value of the pressure gauge 414 and the actual pressure reduction value of the first liquid chamber 316 may be obtained, and the pressure reduction threshold p1 may be corrected based on this relationship. In this case, in S714, it is determined whether the measurement value of the pressure gauge 414 has reached the corrected pressure reduction threshold p1. Furthermore, after it is determined that the pressure reduction value indicated by the pressure gauge 414 has reached the pressure reduction threshold p1, the valve 314 is opened in S720 so that the actual pressure reduction value of the first liquid chamber 316 does not exceed the pressure reduction threshold p1.

[0125] (7) Although not specifically mentioned in the second embodiment, the absolute value of the actual pressure reduction value of the first liquid chamber 316 tends to be larger than the pressure reduction value (measured value) indicated by the pressure gauge 1004. This is because there is pressure loss due to the residual liquid region 1002b in the flow path 1002. Therefore, depending on the configuration of the suction unit 400, the circulation path 1000, the print head 30, etc., the relationship between the measurement value of the pressure gauge 1004 and the actual pressure reduction value of the first liquid chamber 316 may be obtained, and the pressure reduction threshold p1 may be corrected based on this relationship. In this case, in S714, it is determined whether the measurement value of the pressure gauge 1004 has reached the corrected pressure reduction value p1. Furthermore, after it is determined that the pressure reduction value indicated by the pressure gauge 1004 has reached the pressure reduction threshold p1, the valve 314 is opened in S720 so that the actual pressure reduction value of the first liquid chamber 316 does not exceed the pressure reduction threshold p1.

[0126] (8) Although not specifically mentioned in the first embodiment, the pressure reduction threshold obtained by the above formula (1) is a lower limit value of the pressure reduction value based on the volume V1 of the first liquid chamber 316 and the volume A of the region S1. Therefore, for example, the above experiment may be performed to obtain an upper limit value of the pressure reduction value that provides a favorable evaluation of the filling rate of the second liquid chamber and the number of initial non-discharge nozzles, and a predetermined value between this upper limit value and the lower limit value of the pressure reduction value obtained by the above formula (1) may be set as the pressure reduction threshold p1. Similarly, in the second embodiment, an upper limit value of the pressure reduction value according to the configuration of the print head 30, the circulation path 1000, etc. may be obtained, and a predetermined value between this upper limit value and the lower limit value of the pressure reduction value obtained by the above formula (2) may be set as the pressure reduction threshold p1.

[0127] (9) The present invention can also be realized by supplying a program that realizes one or more of the functions of the above-described embodiments to a system or device via a network or a recording medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more of the functions.

[0128] (10) The above embodiment and the various configurations shown in (1) to (9) above may be combined as appropriate.

[0129] The disclosure of the above embodiment includes the following configurations and methods.

[0130] (Configuration 1) a recording means including a first liquid chamber for storing a liquid, and a second liquid chamber that communicates with the first liquid chamber via a filter and stores the liquid transferred from the first liquid chamber, and the stored liquid is ejected through a nozzle; the recording means is detachable, and a circulation path is provided for circulating the liquid by supplying the liquid to the first liquid chamber of the attached recording means while recovering the liquid from the second liquid chamber; a pressure reducing means for reducing the pressure of the first liquid chamber and the second liquid chamber through the nozzle for the recording means attached to the circulation path; a control means for controlling the pressure reducing means to reduce the pressure in the first liquid chamber to a pressure reduction threshold via the nozzle for the recording means attached to the circulation path that is not filled with liquid, thereby causing liquid to flow into the first liquid chamber from a supply flow path of the circulation path, the circulation path includes a first flow path that branches off from the supply flow path that supplies liquid to the recording means and that can communicate the first liquid chamber with the atmosphere when removing the recording means and draining the liquid from the recording means, The pressure reduction threshold is a value that, when air in a predetermined region in the supply flow path and the first flow path expands due to pressure reduction by the pressure reduction means, the volume of the expanded air does not exceed the volume of the first liquid chamber, and is a value that allows liquid to be filled into the recording means. (Configuration 2) 2. The recording apparatus according to claim 1, wherein the predetermined area is an area where the liquid is replaced with air when the liquid is extracted from the recording means removed from the circulation path. (Configuration 3) further comprising a measuring means capable of measuring a pressure reduction value of the first liquid chamber, 3. The recording apparatus according to claim 1, wherein the measuring means is provided in the pressure reducing means. (Configuration 4) The pressure reduction threshold is a relative value from atmospheric pressure, The recording device according to configuration 3, wherein the volume of the first liquid chamber is V1, the volume of the predetermined area is A, and the atmospheric pressure is P0, the pressure reduction threshold p1 satisfies |p1|=P0×V1 / (V1+A). (Configuration 5) further comprising a measuring means capable of measuring a pressure reduction value of the first liquid chamber, the measuring means is provided in a second flow path branched from the first flow path, The recording device according to configuration 1 or 2, characterized in that the pressure reduction threshold is a value such that when the air in the specified area and the air remaining in the second flow path expand when the liquid is extracted from the recording means removed from the circulation path, the volume of the expanded air does not exceed the volume of the first liquid chamber and the recording means can be filled with liquid. (Configuration 6) The pressure reduction threshold is a relative value from atmospheric pressure, The recording device described in configuration 5 is characterized in that, when the volume of the first liquid chamber is V1, the volume of the specified area is A, the volume of the air remaining area in which air remains in the second flow path is Q, and the atmospheric pressure is P0, the pressure reduction threshold p1 satisfies |p1|=P0×V1 / (V1+A+Q). (Configuration 7) 7. The recording device according to configuration 6, wherein the volume of the air remaining region is obtained based on a diameter of the second flow path and a length of the air remaining region in the extension direction of the second flow path. (Configuration 8) The recording device according to configuration 6, characterized in that, when the volume of the second flow path is B and the pressure reduction threshold used in filling the liquid into the most recent recording means is p2, the volume of the air remaining area satisfies Q=B×(P0-|p2|) / P0. (Configuration 9) further comprising a measuring means capable of measuring a pressure reduction value of the first liquid chamber, the circulation path includes a third flow path that joins the supply flow path at a joining portion that is farther away from a connection portion with the recording means than a branching portion where the first flow path branches off, and into which liquid can flow from the supply flow path when a supply pressure of liquid to the recording means increases; the measuring means is provided in a second flow path that branches off from the connection part to the junction part in the supply flow path, The recording device according to configuration 1 or 2, characterized in that the pressure reduction threshold is a value such that when the air in the specified area and the air remaining in the second flow path expand when the liquid is extracted from the recording means removed from the circulation path, the volume of the expanded air does not exceed the volume of the first liquid chamber and the recording means can be filled with liquid. (Configuration 10) 10. The recording apparatus according to any one of configurations 1 to 9, further comprising a degassing means for removing air contained in the liquid circulating through the circulation path. (Configuration 11) 10. The recording apparatus according to any one of configurations 3 to 9, wherein the pressure reduction threshold is corrected based on the relationship between the pressure reduction value in the first liquid chamber and the value measured by the measuring means. (Configuration 12) a recording means including a first liquid chamber for storing a liquid, and a second liquid chamber that communicates with the first liquid chamber via a filter and stores the liquid transferred from the first liquid chamber, and the stored liquid is ejected through a nozzle; the recording means is detachable, and a circulation path is provided for circulating the liquid by supplying the liquid to the first liquid chamber of the attached recording means while recovering the liquid from the second liquid chamber; a pressure reducing means for reducing the pressure of the first liquid chamber and the second liquid chamber through the nozzle for the recording means attached to the circulation path, a control method for a recording device, wherein the circulation path is formed with a first flow path that branches off from a supply flow path that supplies liquid to the recording means and that can communicate the first liquid chamber with the atmosphere when removing the liquid from the recording means, a step of decompressing the first liquid chamber through the nozzle by the decompression means for the recording means attached to the circulation path that is not filled with liquid; When the pressure in the first liquid chamber reaches a pressure reduction threshold, the liquid is caused to flow from the supply flow path into the first liquid chamber by controlling the transfer of the liquid in the circulation path; a control method characterized in that the pressure reduction threshold is a value at which, when air in a predetermined region in the supply flow path and the first flow path expands due to pressure reduction by the pressure reduction means, the volume of the expanded air does not exceed the volume of the first liquid chamber and at which liquid can be filled into the recording means. [Explanation of symbols]

[0131] 10 Recording Device 30 Recording head 222 Print Controller 300, 1000 circulation route 400 Suction part

Claims

1. a recording means including a first liquid chamber for storing a liquid, and a second liquid chamber that communicates with the first liquid chamber via a filter and stores the liquid transferred from the first liquid chamber, and the stored liquid is ejected through a nozzle; the recording means is detachable, and a circulation path is provided for circulating the liquid by supplying the liquid to the first liquid chamber of the attached recording means while recovering the liquid from the second liquid chamber; a pressure reducing means for reducing the pressure of the first liquid chamber and the second liquid chamber via the nozzle for the recording means attached to the circulation path; a control means for controlling the pressure reducing means to reduce the pressure in the first liquid chamber to a pressure reduction threshold via the nozzle for the recording means attached to the circulation path that is not filled with liquid, thereby causing liquid to flow into the first liquid chamber from a supply flow path of the circulation path, the circulation path includes a first flow path that branches off from the supply flow path that supplies liquid to the recording means and that can communicate the first liquid chamber with the atmosphere when liquid is removed from the recording means, The pressure reduction threshold is a value that, when air in a predetermined region in the supply flow path and the first flow path expands due to pressure reduction by the pressure reduction means, the volume of the expanded air does not exceed the volume of the first liquid chamber, and is a value that allows liquid to be filled into the recording means.

2. 2. The recording apparatus according to claim 1, wherein the predetermined area is an area where the liquid is replaced with air when the liquid is extracted from the recording means removed from the circulation path.

3. further comprising a measuring means for measuring a pressure reduction value of the first liquid chamber, 2. The recording apparatus according to claim 1, wherein the measuring means is provided in the pressure reducing means.

4. The pressure reduction threshold is a relative value from atmospheric pressure, 4. The recording apparatus according to claim 3, wherein the pressure reduction threshold p1 satisfies |p1|=P0×V1 / (V1+A), where V1 is the volume of the first liquid chamber, A is the volume of the specified area, and P0 is the atmospheric pressure.

5. further comprising a measuring means for measuring a pressure reduction value of the first liquid chamber, the measuring means is provided in a second flow path branched from the first flow path, The recording device according to claim 1, characterized in that the pressure reduction threshold is a value such that when the air in the specified area and the air remaining in the second flow path expand when liquid is extracted from the recording means removed from the circulation path, the volume of the expanded air does not exceed the volume of the first liquid chamber and the recording means can be filled with liquid.

6. The pressure reduction threshold is a relative value from atmospheric pressure, The recording device described in claim 5, characterized in that when the volume of the first liquid chamber is V1, the volume of the specified area is A, the volume of the air remaining area in which air remains in the second flow path is Q, and the atmospheric pressure is P0, the pressure reduction threshold p1 satisfies |p1| = P0 × V1 / (V1 + A + Q).

7. 7. The recording apparatus according to claim 6, wherein the volume of the air remaining region is obtained based on a diameter of the second flow path and a length of the air remaining region in the extension direction of the second flow path.

8. The recording device according to claim 6, characterized in that, when the volume of the second flow path is B and the pressure reduction threshold used in filling the liquid into the most recent recording means is p2, the volume of the air remaining area satisfies Q = B x (P0 - |p2|) / P0.

9. further comprising a measuring means for measuring a pressure reduction value of the first liquid chamber, the circulation path includes a third flow path that joins the supply flow path at a joining portion that is farther from a connection portion with the recording means than a branch portion at which the first flow path branches in the supply flow path, and into which liquid can flow from the supply flow path when a supply pressure of liquid to the recording means increases, the measuring means is provided in a second flow path that branches off from the connection portion to the junction portion in the supply flow path, The recording device according to claim 1, characterized in that the pressure reduction threshold is a value such that when the air in the specified area and the air remaining in the second flow path expand when liquid is extracted from the recording means removed from the circulation path, the volume of the expanded air does not exceed the volume of the first liquid chamber and the recording means can be filled with liquid.

10. 10. The recording apparatus according to claim 1, further comprising a degassing unit for removing air contained in the liquid circulating through the circulation path.

11. 10. The recording apparatus according to claim 3, wherein the pressure reduction threshold is corrected based on the relationship between the pressure reduction value in the first liquid chamber and the value measured by the measuring means.

12. a recording means including a first liquid chamber for storing a liquid, and a second liquid chamber that communicates with the first liquid chamber via a filter and stores the liquid transferred from the first liquid chamber, and the stored liquid is ejected through a nozzle; the recording means is detachable, and a circulation path is provided for circulating the liquid by supplying the liquid to the first liquid chamber of the attached recording means while recovering the liquid from the second liquid chamber; a pressure reducing means for reducing the pressure in the first liquid chamber and the second liquid chamber via the nozzle for the recording means attached to the circulation path, a control method for a recording device in which a first flow path is formed in the circulation path, the first flow path being branched off from a supply flow path that supplies liquid to the recording means, and capable of communicating the first liquid chamber with the atmosphere when removing the liquid from the recording means, a step of decompressing the first liquid chamber through the nozzle by the decompression means for the recording means attached to the circulation path that is not filled with liquid; When the pressure in the first liquid chamber reaches a pressure reduction threshold, the liquid is transferred through the circulation path and the liquid flows from the supply flow path into the first liquid chamber. a control method characterized in that the pressure reduction threshold is a value such that, when air in a specified region in the supply flow path and the first flow path expands due to pressure reduction by the pressure reduction means, the volume of the expanded air does not exceed the volume of the first liquid chamber and is capable of filling the recording means with liquid.

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