Inkjet recording apparatus and recovery method

Abstract

An inkjet recording device and a recovery method are provided that suppress the increase in viscosity of ink at ejection ports during suction processing of the ejection ports. A vacuum wiper 172c is brought into contact with the ejection port surface 8a of the recording head 8 and moved to sequentially perform a vacuum wiping process on the arranged ejection ports. Ink is circulated in the flow paths, including the flow paths that communicate with the ejection ports for which the vacuum wiping process has been completed.

Description

[Technical field]

[0001] The present invention relates to an inkjet printing apparatus that prints by ejecting ink onto a printing medium, and to a recovery method for maintaining and recovering a good ink ejection state from a print head that ejects ink. [Background technology]

[0002] Patent Document 1 discloses a technology relating to a recovery process that maintains and recovers the ink ejection performance of an ejection port by placing a vacuum nozzle opposite the ejection port that ejects ink and forcibly sucking ink from the ejection port by suction with the vacuum nozzle. In the technology disclosed in Patent Document 1, a vacuum nozzle capable of sucking one or several ejection ports is moved from one end to the other end of an ejection port row formed by arranging a plurality of ejection ports, and sucks each ejection port. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-201028 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the ink in the treated ejection ports continues to be exposed to the atmosphere until the recovery process for the ejection ports is completed. Here, for example, if there are many ejection ports to be subjected to the recovery process or if the ejection port array is long, the recovery process will take a long time, and the ink in the ejection ports that have already been processed will be exposed to the atmosphere for a long time. This causes the ink in the ejection ports to thicken, and there is a risk that the ejection performance cannot be sufficiently maintained despite the recovery process being performed.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an inkjet recording device and a recovery method that prevent the loss of ejection performance of an ejection port whose ejection performance has been restored by a recovery process for the ejection port. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention Inkjet recording device A plurality of ejection ports for ejecting ink a recording head including: a recording element for ejecting ink from the ejection ports; pressure chambers communicating with the ejection ports provided at positions corresponding to the recording elements and corresponding to each of the ejection ports; a first flow path capable of supplying ink to the pressure chamber; and a second flow path capable of recovering ink from the pressure chamber; Recording head a discharge port surface on which the plurality of discharge ports are formed, a suction unit that performs a suction process to suck ink from the ejection port; The ink is caused to flow from the first flow path through the pressure chamber to the second flow path without being discharged from the ejection port. A circulation means for circulating the having During the suction process by the suction means, Yes The feature of this method is that it circulates ink. Effect of the Invention

[0007] According to the present invention, it is possible to prevent the ejection performance of an ejection port, the ejection performance of which has been restored by a restoration process for the ejection port, from being impaired. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing the recording device in a standby state. [Diagram 2] FIG. 2 is a control configuration diagram of the recording apparatus. [Diagram 3] FIG. 2 is a diagram showing the recording device in a recording state. [Figure 4] FIG. 2 is a diagram showing the recording apparatus in a maintenance state. [Diagram 5] FIG. 2 is a perspective view showing a configuration of a maintenance unit. [Figure 6] FIG. 2 is a schematic diagram of an ink supply system. [Figure 7] 3A and 3B are diagrams illustrating the flow of ink in a flow channel including an ejection port. [Figure 8] 1 is a diagram showing a main part of a recording apparatus according to a first embodiment of the present invention. [Figure 9]FIG. 2 is a diagram showing a substrate disposed on a discharge port surface and discharge ports formed in the substrate; [Figure 10] 13 is a flowchart showing the process contents of a first vacuum wiping process. [Figure 11] 6A and 6B are diagrams illustrating thickening of ink due to circulation in a flow path including an ejection port. [Figure 12] 13 is a flowchart showing the processing contents of a second vacuum wiping process. [Figure 13] FIG. 11 is a diagram showing a main part of a recording apparatus according to a third embodiment of the present invention. [Figure 14] 13 is a flowchart showing the process contents of a third vacuum wiping process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (First embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The following embodiment does not limit the present invention, and not all of the combinations of features described in the present embodiment are necessarily essential to the solution of the present invention. Note that the relative arrangements and shapes of the components described in the embodiments are merely examples, and are not intended to limit the scope of the present invention to only those. In the following embodiment, an inkjet recording device having a recording head that ejects ink will be described as an example of a liquid ejection device equipped with a liquid ejection head that ejects droplets.

[0010] 1 is a diagram showing the internal configuration of an inkjet recording apparatus 1 (hereinafter, recording apparatus 1) used in this embodiment. In the figure, the x direction indicates the horizontal direction, the y direction (perpendicular to the paper surface) indicates the direction in which ejection ports are arranged in a recording head 8 (described later), and the z direction indicates the vertical direction.

[0011] The recording device 1 is a multifunction device equipped with a print unit 2 and a scanner unit 3, and various processes related to recording and reading operations can be executed by the print unit 2 and the scanner unit 3 individually or in conjunction with each other. The scanner unit 3 is equipped with an ADF (automatic document feeder) and an FBS (flatbed scanner), and can read documents automatically fed by the ADF and read (scan) documents placed on the platen of the FBS by a user. Note that although this embodiment is a multifunction device equipped with both the print unit 2 and the scanner unit 3, it may be configured not to include the scanner unit 3. FIG. 1 shows the recording device 1 in a standby state in which neither recording nor reading operations are being performed.

[0012] In the printing section 2, a first cassette 5A and a second cassette 5B for accommodating recording media (cut sheets) S are removably installed at the bottom vertically below the housing 4. The first cassette 5A accommodates relatively small recording media up to A4 size, while the second cassette 5B accommodates relatively large recording media up to A3 size, stacked flat. A first feeding unit 6A is provided near the first cassette 5A for separating and feeding the accommodated recording media one by one. Similarly, a second feeding unit 6B is provided near the second cassette 5B. When a recording operation is performed, the recording media S is selectively fed from one of the cassettes.

[0013] The transport roller 7, discharge roller 12, pinch roller 7a, spur 7b, guide 18, inner guide 19, and flapper 11 constitute a transport mechanism for guiding the recording medium S in a predetermined direction. The transport rollers 7 are disposed upstream and downstream of the recording head 8, and are drive rollers driven by a transport motor (not shown). The pinch roller 7a is a driven roller that nips the recording medium S together with the transport roller 7 and rotates. The discharge roller 12 is disposed downstream of the transport roller 7, and is a drive roller driven by a transport motor (not shown). The spur 7b, together with the transport roller 7 and the discharge roller 12 disposed downstream of the recording head 8, pinches and transports the recording medium S.

[0014] The guide 18 is provided on the transport path of the recording medium S and guides the recording medium S in a predetermined direction. The inner guide 19 is a member extending in the y direction, has a curved side, and guides the recording medium S along the side. The flapper 11 is a member for switching the direction in which the recording medium S is transported during double-sided recording operation. The discharge tray 13 is a tray for stacking and holding the recording medium S discharged by the discharge roller 12 after the recording operation is completed.

[0015] The recording head 8 of this embodiment is a full-line type color inkjet recording head, and a plurality of ejection ports for ejecting ink according to recording data are arranged in the y direction in FIG. 1 in a width corresponding to the recording medium S. That is, the recording head 8 is configured to be able to eject ink of a plurality of colors. When the recording head 8 is in the standby position, the ejection port surface 8a of the recording head 8 faces vertically downward as shown in FIG. 1 and is capped by the cap unit 10. When performing a recording operation, the orientation of the recording head 8 is changed by a print controller 202 described later so that the ejection port surface 8a faces a platen 9. The platen 9 is formed of a flat plate extending in the y direction, and supports the recording medium S on which the recording operation is performed by the recording head 8 from the rear. The movement of the recording head 8 from the standby position to the recording position will be described in detail later.

[0016] The ink tank unit 14 stores each of the four colors of ink to be supplied to the recording head 8. The ink supply unit 15 is provided in the middle of a flow path connecting the ink tank unit 14 and the recording head 8, and adjusts the pressure and flow rate of the ink in the recording head 8 to appropriate ranges. In this embodiment, a circulation type ink supply system is adopted, and the ink supply unit 15 adjusts the pressure of the ink supplied to the recording head 8 and the flow rate of the ink collected from the recording head 8 to appropriate ranges.

[0017] The maintenance unit 16 includes a cap unit 10 and a wiping unit 17, and operates these at a predetermined timing to perform a maintenance operation on the recording head 8. The maintenance operation will be described in detail later.

[0018] 2 is a block diagram showing the control configuration of the recording apparatus 1. The control configuration mainly comprises a print engine unit 200 that controls the print section 2, a scanner engine unit 300 that controls the scanner section 3, and a controller unit 100 that controls the entire recording apparatus 1. A print controller 202 controls various mechanisms of the print engine unit 200 according to instructions from a main controller 101 of the controller unit 100. Various mechanisms of the scanner engine unit 300 are controlled by the main controller 101 of the controller unit 100. The control configuration will be described in detail below.

[0019] In the controller unit 100, a main controller 101 constituted by a CPU controls the entire recording device 1 using a RAM 106 as a work area in accordance with programs and various parameters stored in a ROM 107. For example, when a print job is input from a host device 400 via a host I / F 102 or a wireless I / F 103, an image processing unit 108 performs predetermined image processing on the received image data in accordance with instructions from the main controller 101. The main controller 101 then transmits the processed image data to a print engine unit 200 via a print engine I / F 105.

[0020] The recording device 1 may obtain image data from the host device 400 via wireless communication or wired communication, or may obtain image data from an external storage device (such as a USB memory) connected to the recording device 1. The communication method used for wireless communication or wired communication is not limited. For example, Wi-Fi (Wireless Fidelity) (registered trademark) or Bluetooth (registered trademark) can be used as a communication method used for wireless communication. Also, USB (Universal Serial Bus) or the like can be used as a communication method used for wired communication. Also, for example, when a read command is input from the host device 400, the main controller 101 transmits the command to the scanner unit 3 via the scanner engine I / F 109.

[0021] The operation panel 104 is a mechanism for a user to perform input and output to the recording device 1. The user can instruct operations such as copying and scanning, set the print mode, and recognize information about the recording device 1 via the operation panel 104.

[0022] In the print engine unit 200, a print controller 202 constituted by a CPU controls various mechanisms of the print section 2 according to programs and various parameters stored in a ROM 203, using a RAM 204 as a work area. When various commands and image data are received via a controller I / F 201, the print controller 202 temporarily stores them in the RAM 204. The print controller 202 causes an image processing controller 205 to convert the stored image data into print data so that the print head 8 can use it for a printing operation. When the print data is generated, the print controller 202 causes the print head 8 to execute a printing operation based on the print data via a head I / F 206. At this time, the print controller 202 drives the feed units 6A and 6B, the conveyance roller 7, the discharge roller 12, and the flapper 11 shown in FIG. 1 via a conveyance control section 207 to convey the recording medium S. According to an instruction from the print controller 202, the recording head 8 executes a recording operation in conjunction with the conveyance operation of the recording medium S, and print processing is performed.

[0023] The head carriage control unit 208 changes the orientation and position of the recording head 8 depending on the operating state, such as the maintenance state and recording state, of the recording device 1. The ink supply control unit 209 controls the ink supply unit 15 so that the pressure of the ink supplied to the recording head 8 falls within an appropriate range. The maintenance control unit 210 controls the operations of the cap unit 10 and the wiping unit 17 in the maintenance unit 16 when performing a maintenance operation on the recording head 8.

[0024] In the scanner engine unit 300, the main controller 101 controls the hardware resources of the scanner controller 302 using the RAM 106 as a work area according to the program and various parameters stored in the ROM 107. This controls various mechanisms of the scanner unit 3. For example, the main controller 101 controls the hardware resources in the scanner controller 302 via the controller I / F 301, so that a document placed on the ADF by a user is conveyed via the conveyance control unit 304 and read by the sensor 305. The scanner controller 302 then stores the read image data in the RAM 303. The print controller 202 can convert the image data acquired as described above into print data, thereby causing the print head 8 to perform a print operation based on the image data read by the scanner controller 302.

[0025] Fig. 3 shows the recording apparatus 1 in a recording state. Compared to the standby state shown in Fig. 1, the cap unit 10 is spaced away from the ejection port surface 8a of the recording head 8, and the ejection port surface 8a faces the platen 9. In this embodiment, the plane of the platen 9 is inclined at about 45 degrees with respect to the horizontal direction, and the ejection port surface 8a of the recording head 8 in the recording position is also inclined at about 45 degrees with respect to the horizontal direction so that the distance from the platen 9 is maintained constant.

[0026] When the recording head 8 moves from the standby position shown in FIG. 1 to the recording position shown in FIG. 3, the print controller 202 uses the maintenance control unit 210 to lower the cap unit 10 to the retracted position shown in FIG. 3. This separates the ejection port surface 8a of the recording head 8 from the cap member 10a. Thereafter, the print controller 202 uses the head carriage control unit 208 to rotate the recording head 8 by 45 degrees while adjusting the vertical height of the recording head 8, so that the ejection port surface 8a faces the platen 9. When the recording operation is completed and the recording head 8 moves from the recording position to the standby position, the print controller 202 performs the above steps in reverse.

[0027] Next, a description will be given of the maintenance operation for the recording head 8. As described in Fig. 1, the maintenance unit 16 of this embodiment includes a cap unit 10 and a wiping unit 17, and performs the maintenance operation by operating these at a predetermined timing.

[0028] Fig. 4 is a diagram showing the recording device 1 in a maintenance state. When moving the recording head 8 from the standby position shown in Fig. 1 to the maintenance position shown in Fig. 4, the print controller 202 moves the recording head 8 upward in the vertical direction and moves the cap unit 10 downward in the vertical direction. Then, the print controller 202 moves the wiping unit 17 from the retracted position to the right in Fig. 4. After that, the print controller 202 moves the recording head 8 downward in the vertical direction to a maintenance position where maintenance operation is possible.

[0029] On the other hand, when the recording head 8 moves from the recording position shown in Fig. 3 to the maintenance position shown in Fig. 4, the print controller 202 moves the recording head 8 vertically upward while rotating it 45 degrees. Then, the print controller 202 moves the wiping unit 17 from the retracted position to the right. After that, the print controller 202 moves the recording head 8 vertically downward to a maintenance position where the maintenance operation by the maintenance unit 16 can be performed.

[0030] FIG. 5(a) is a perspective view showing a state in which the maintenance unit 16 is in a standby position, and FIG. 5(b) is a perspective view showing a state in which the maintenance unit 16 is in a maintenance position. FIG. 5(a) corresponds to FIG. 1, and FIG. 5(b) corresponds to FIG. 4. When the recording head 8 is in the standby position, the maintenance unit 16 is in the standby position shown in FIG. 5(a), the cap unit 10 moves vertically upward, and the wiping unit 17 is stored inside the maintenance unit 16. The cap unit 10 has a box-shaped cap member 10a extending in the y direction, and by bringing this into close contact with the discharge port surface 8a of the recording head 8, it is possible to suppress evaporation of ink from the discharge port. The cap unit 10 also has a function of collecting ink discharged by preliminary discharge or the like into the cap member 10a, and having the collected ink sucked by a suction pump (not shown).

[0031] 5(b), the cap unit 10 has moved vertically downward, and the wiping unit 17 has been pulled out from the maintenance unit 16. The wiping unit 17 includes two wiper units: a blade wiper unit 171 and a vacuum wiper unit 172.

[0032] In the blade wiper unit 171, a blade wiper 171a for wiping the ejection port surface 8a along the x direction is arranged in the y direction by a length corresponding to the arrangement area of ​​the ejection ports. When performing a wiping operation using the blade wiper unit 171, the wiping unit 17 moves the blade wiper unit 171 in the x direction with the recording head 8 positioned at a height that allows it to abut against the blade wiper 171a. With this movement, ink and the like adhering to the ejection port surface 8a is wiped off by the blade wiper 171a.

[0033] A wet wiper cleaner 16a is disposed at the entrance of the maintenance unit 16 when the blade wiper 171a is stored, for removing ink adhering to the blade wiper 171a and applying wet liquid to the blade wiper 171a. Every time the blade wiper 171a is stored in the maintenance unit 16, the wet wiper cleaner 16a removes adhering matter and applies wet liquid to the blade wiper 171a. When the ejection port surface 8a is wiped next time, the wet liquid is transferred to the ejection port surface 8a, improving the slipperiness between the ejection port surface 8a and the blade wiper 171a.

[0034] On the other hand, the vacuum wiper unit 172 has a flat plate 172a having an opening extending in the y direction, a carriage 172b movable in the y direction within the opening, and a vacuum wiper 172c mounted on the carriage 172b. The vacuum wiper 172c is arranged so as to be able to wipe the discharge port surface 8a in the y direction as the carriage 172b moves. A suction port connected to the suction pump 32 (see FIG. 8) is formed at the tip of the vacuum wiper 172c. Therefore, when the carriage 172b is moved in the y direction while the suction pump 32 is operated, the ink and the like adhering to the discharge port surface 8a of the recording head 8 is sucked into the suction port while being wiped by the vacuum wiper 172c. At this time, the positioning pins 172d provided at both ends of the opening of the flat plate 172a are used to align the vacuum wiper 172c with respect to the discharge port surface 8a.

[0035] In this embodiment, a first wiping process in which the wiping operation is performed by the blade wiper unit 171 and not by the vacuum wiper unit 172, and a second wiping process in which both wiping processes are performed in sequence can be performed. When performing the first wiping process, the print controller 202 first pulls out the wiping unit 17 from the maintenance unit 16 in a state in which the recording head 8 is retracted vertically upward from the maintenance position in FIG. 4. Then, the print controller 202 moves the recording head 8 vertically downward to a position where it can abut against the blade wiper 171a, and then moves the wiping unit 17 into the maintenance unit 16. By this movement, ink and the like adhering to the ejection port surface 8a are wiped off by the blade wiper 171a. That is, the blade wiper 171a wipes the ejection port surface 8a when it moves into the maintenance unit 16 from the position where it is pulled out from the maintenance unit 16.

[0036] When the blade wiper unit 171 is stored, the print controller 202 then moves the cap unit 10 vertically upward to bring the cap member 10a into close contact with the ejection port surface 8a of the recording head 8. Then, the print controller 202 drives the recording head 8 in this state to perform preliminary ejection, and sucks the ink collected in the cap member 10a with the suction pump.

[0037] On the other hand, when performing the second wiping process, the print controller 202 first slides and pulls out the wiping unit 17 from the maintenance unit 16 while retracting the recording head 8 vertically upward from the maintenance position in FIG. 4. Then, the print controller 202 moves the recording head 8 vertically downward to a position where it can abut against the blade wiper 171a, and then moves the wiping unit 17 into the maintenance unit 16. This allows the blade wiper 171a to perform a wiping operation on the discharge port surface 8a. Next, the print controller 202 slides and pulls out the wiping unit 17 from the maintenance unit 16 to a predetermined position while retracting the recording head 8 vertically upward from the maintenance position in FIG. 4 again. Next, the print controller 202 uses the flat plate 172a and the positioning pin 172d to position the discharge port surface 8a and the vacuum wiper unit 172 while lowering the recording head 8 to the maintenance position shown in FIG. 4. Thereafter, the print controller 202 executes the wiping operation by the above-mentioned vacuum wiper unit 172. The print controller 202 retracts the recording head 8 vertically upward and stores the wiping unit 17, and then performs the preliminary ejection into the cap member by the cap unit 10 and the suction operation of the collected ink, similar to the first wiping process.

[0038] Hereinafter, the wiping operation using the vacuum wiper unit 172 will be referred to as vacuum wiping. Also, a series of operations for performing vacuum wiping, that is, operations from the operation of retracting the recording head 8 vertically upward from the maintenance position again to the operation of completing the wiping operation by the vacuum wiper unit 172, will be referred to as vacuum wiping processing.

[0039] Here, the vacuum wiping process is a process of wiping the ejection port surface 8a while applying a negative pressure. In the vacuum wiping process, the negative pressure applied to the ejection port surface 8a and the time for which the negative pressure is applied can be adjusted. Therefore, the vacuum wiping is superior in the performance of removing ink from the ejection port surface 8a compared to the wiping operation using the blade wiper 171a, and a high cleaning effect can be obtained. As a result, the ink that has adhered and thickened on the ejection port surface 8a can be removed more reliably than the wiping operation using the blade wiper 171a. Therefore, in the second wiping process in which vacuum wiping is performed in addition to the wiping operation using the blade wiper 171a, the ink that has adhered and thickened on the ejection port surface 8a can be removed more reliably.

[0040] Next, the ink supply system of the recording head 8 will be described. In this embodiment, as described above, a circulation type ink supply system is adopted. FIG. 6 is a diagram showing the flow path configuration of a circulation type ink supply system including an ink supply unit 15 adopted in the inkjet recording device 1 of this embodiment. The ink supply unit 15 supplies ink supplied from the ink tank unit 14 to the recording head 8. Although FIG. 6 shows a configuration for one color of ink, in reality, such a configuration is prepared for each ink color. The ink supply unit 15 is basically controlled by the ink supply control unit 209 via the print controller 202. That is, in this embodiment, the print controller 202 (and the ink supply control unit 209) functions as a control unit that controls the circulation of ink in the flow path. Each configuration of the ink supply unit 15 will be described below.

[0041] Ink is mainly circulated between the subtank 151 and the recording head 8. In the recording head 8, the ink is discharged based on image data, and any ink that is not discharged is collected back into the subtank 151. The ink in the discharge port is exposed to the atmosphere, and the liquid components in the ink evaporate and thicken, which may reduce the discharge performance of the discharge port. In response to this, by circulating the ink, the ink in the discharge port is replaced with new ink before the liquid components evaporate to a degree that would reduce the discharge performance of the discharge port, thereby suppressing thickening and the like.

[0042] The subtank 151, which contains a predetermined amount of ink, is connected to a supply flow path C2 for supplying ink to the recording head 8 and a recovery flow path C4 for recovering ink from the recording head 8. That is, the subtank 151, the supply flow path C2, the recording head 8, and the recovery flow path C4 form a circulation flow path (circulation route) through which the ink circulates. The subtank 151 is also connected to a flow path C0 through which air flows.

[0043] The subtank 151 is provided with a liquid level detection means 151a consisting of multiple electrode pins. The ink supply control unit 209 can grasp the ink level, i.e., the amount of ink remaining in the subtank 151, by detecting the presence or absence of a conductive current between these multiple pins. The pressure reduction pump P0 (intra-tank pressure reduction pump) is a negative pressure generating source for reducing the pressure inside the subtank 151. The atmosphere release valve V0 is a valve for switching whether or not the inside of the subtank 151 is connected to the atmosphere.

[0044] The main tank 141 is a tank that contains ink to be supplied to the sub tank 151. The main tank 141 is detachable from the recording apparatus body. A tank supply valve V1 for switching the connection between the sub tank 151 and the main tank 141 is provided in the middle of a tank connection flow path C1 that connects the sub tank 151 and the main tank 141.

[0045] When the ink level detection means 151a detects that the ink in the subtank 151 is less than a predetermined amount, the ink supply control unit 209 closes the atmosphere release valve V0, the supply valve V2, the recovery valve V4, and the head replacement valve V5. The ink supply control unit 209 also opens the tank supply valve V1. In this state, the ink supply control unit 209 operates the pressure reduction pump P0. This creates a negative pressure inside the subtank 151, and ink is supplied from the main tank 141 to the subtank 151. When the ink level detection means 151a detects that the ink in the subtank 151 has exceeded a predetermined amount, the ink supply control unit 209 closes the tank supply valve V1 and stops the pressure reduction pump P0.

[0046] The supply flow path C2 is a flow path for supplying ink from the sub tank 151 to the recording head 8, and a supply pump P1 and a supply valve V2 are arranged along the way. During a recording operation, the supply pump P1 is driven with the supply valve V2 open, so that ink can be circulated in the circulation path while being supplied to the recording head 8. The amount of ink ejected per unit time by the recording head 8 varies according to image data. The flow rate of the supply pump P1 is determined so as to be able to handle the case where the recording head 8 performs an ejection operation that consumes the maximum amount of ink per unit time.

[0047] The relief flow path C3 is upstream of the supply valve V2 and is a flow path that connects the upstream and downstream sides of the supply pump P1. A relief valve V3, which is a differential pressure valve, is disposed in the middle of the relief flow path C3. The relief valve V3 is spring-biased, not opened and closed by a drive mechanism, and is configured to open when a predetermined pressure is reached. For example, when the ink supply amount per unit time from the supply pump P1 is greater than the total value of the discharge amount per unit time of the recording head 8 and the flow rate (amount of ink drawn) per unit time of the recovery pump P2, the relief valve V3 opens according to the pressure acting on itself. This forms a circulating flow path consisting of a part of the supply flow path C2 and the relief flow path C3. By providing the configuration of the relief flow path C3, the ink supply amount to the recording head 8 is adjusted according to the ink consumption amount in the recording head 8, and the pressure in the circulation path can be stabilized regardless of the image data.

[0048] The recovery flow path C4 is a flow path for recovering ink from the recording head 8 to the subtank 151, and a recovery pump P2 and a recovery valve V4 are arranged along the way. When circulating ink in the circulation path, the recovery pump P2 serves as a negative pressure generating source to suck ink from the recording head 8. By driving the recovery pump P2, an appropriate pressure difference is generated between the IN flow path 80b and the OUT flow path 80c in the recording head 8, and ink can be circulated between the IN flow path 80b and the OUT flow path 80c.

[0049] The recovery valve V4 is also a valve for preventing backflow when no printing operation is being performed, i.e., when no ink is circulating in the circulation path. In the circulation path of this embodiment, the subtank 151 is disposed vertically above the print head 8 (see FIG. 1). Therefore, when the supply pump P1 and the recovery pump P2 are not driven, there is a risk that ink will flow back from the subtank 151 to the print head 8 in the recovery flow path C4 due to the head difference between the subtank 151 and the print head 8. To prevent such backflow, in this embodiment, the recovery valve V4 is provided in the recovery flow path C4.

[0050] In addition, the supply valve V2 also functions as a valve to prevent the supply of ink from the subtank 151 to the print head 8 when no printing operation is being performed, i.e., when ink is not circulating in the circulation path.

[0051] The head replacement flow path C5 is a flow path that connects the supply flow path C2 and the air chamber (space that does not contain ink) of the subtank 151, and a head replacement valve V5 is disposed midway through the flow path. One end of the head replacement flow path C5 is connected to the upstream side of the recording head 8 in the supply flow path C2 and downstream of the supply valve V2. The other end of the head replacement flow path C5 is connected to the upper part of the subtank 151 and communicates with the air chamber inside the subtank 151. The head replacement flow path C5 is used when extracting ink from the recording head 8 in use, such as when replacing the recording head 8 or when transporting the recording device 1. The head replacement valve V5 is controlled by the ink supply control unit 209 so as to be closed except when filling the recording head 8 with ink and when recovering ink from the recording head 8 via the head replacement flow path C5.

[0052] Next, the flow path configuration in the recording head 8 will be described. The ink supplied to the recording head 8 from the supply flow path C2 passes through a filter 83, and is then supplied to a first negative pressure control unit 81 and a second negative pressure control unit 82. The first negative pressure control unit 81 has a control pressure set to a weak negative pressure (negative pressure with a small pressure difference from atmospheric pressure). The second negative pressure control unit 82 has a control pressure set to a strong negative pressure (negative pressure with a large pressure difference from atmospheric pressure). The pressures in the first negative pressure control unit 81 and the second negative pressure control unit 82 are generated within an appropriate range by driving the recovery pump P2.

[0053] The recording head 8 includes an ink ejection section 80 for ejecting ink. In the ink ejection section 80, a plurality of recording element substrates 80a, each having a plurality of ejection ports arranged therein, are arranged to form a long ejection port array. A common supply flow path 80b (IN flow path) for guiding ink supplied from a first negative pressure control unit 81 and a common recovery flow path 80c (OUT flow path) for guiding ink supplied from a second negative pressure control unit 82 also extend in the arrangement direction of the recording element substrates 80a. Furthermore, in each recording element substrate 80a, an individual supply flow path connected to the common supply flow path 80b and an individual recovery flow path connected to the common recovery flow path 80c are formed. Therefore, in each recording element substrate 80a, a flow of ink is generated in which ink flows in from the common supply flow path 80b, which has a relatively weak negative pressure, and flows out to the common recovery flow path 80c, which has a relatively strong negative pressure. In the path between the individual supply flow paths and the individual recovery flow paths, pressure chambers that communicate with each ejection port and are filled with ink are provided, and ink flows even in ejection ports and pressure chambers that are not performing printing. When an ejection operation is performed on the printing element substrate 80a, part of the ink moving from the common supply flow path 80b to the common recovery flow path 80c is consumed by being ejected from the ejection port, but the ink that is not ejected moves to the recovery flow path C4 via the common recovery flow path 80c.

[0054] Fig. 7(a) is a schematic plan view of an enlarged portion of the recording element substrate 80a, and Fig. 7(b) is a schematic cross-sectional view taken along the cross-sectional line VIIb-VIIb in Fig. 7(a). The recording element substrate 80a is provided with pressure chambers 1005 filled with ink and ejection ports 1006 for ejecting ink. In the pressure chambers 1005, recording elements 1004 are provided at positions facing the ejection ports 1006. In addition, the recording element substrate 80a is provided with a plurality of individual supply flow paths 1008 connected to the common supply flow path 80b and individual recovery flow paths 1009 connected to the common recovery flow path 80c, each for each ejection port 1006.

[0055] With the above-mentioned configuration, in the recording element substrate 80a, a flow of ink is generated in which the ink flows in from the common supply flow path 80b, which has a relatively weak negative pressure (high absolute pressure value), and flows out to the common recovery flow path 80c, which has a relatively strong negative pressure (low absolute pressure value). More specifically, the ink flows in the order of the common supply flow path 80b → individual supply flow path 1008 → pressure chamber 1005 → individual recovery flow path 1009 → common recovery flow path 80c. When ink is ejected by the recording element 1004, a part of the ink moving from the common supply flow path 80b to the common recovery flow path 80c is ejected from the ejection port 1006 and discharged to the outside of the recording head 8. On the other hand, the ink not ejected from the ejection port 1006 is ejected to the recovery flow path C4 via the common recovery flow path 80c.

[0056] When performing a recording operation with the above configuration, the ink supply control unit 209 closes the tank supply valve V1 and the head replacement valve V5, opens the atmosphere release valve V0, the supply valve V2, and the recovery valve V4, and drives the supply pump P1 and the recovery pump P2. This establishes a circulation path from the subtank 151 to the supply flow path C2 to the recording head 8 to the recovery flow path C4 to the subtank 151. When the amount of ink supplied per unit time from the supply pump P1 is greater than the sum of the amount of ink discharged per unit time from the recording head 8 and the flow rate per unit time in the recovery pump P2, ink flows from the supply flow path C2 to the relief flow path C3. This adjusts the flow rate of ink flowing from the supply flow path C2 to the recording head 8.

[0057] When no printing operation is being performed, the ink supply control unit 209 stops the supply pump P1 and the recovery pump P2, and closes the atmosphere release valve V0, the supply valve V2, and the recovery valve V4. This stops the flow of ink in the print head 8, and also suppresses backflow due to the head difference between the subtank 151 and the print head 8. Closing the atmosphere release valve V0 also suppresses ink leakage from the subtank 151 and ink evaporation.

[0058] When recovering ink from the recording head 8, the ink supply control unit 209 closes the atmosphere release valve V0, the tank supply valve V1, the supply valve V2, and the recovery valve V4, opens the head replacement valve V5, and drives the pressure reducing pump P0. This creates a negative pressure state inside the subtank 151, and the ink in the recording head 8 is recovered to the subtank 151 via the head replacement flow path C5. In this way, the head replacement valve V5 is closed during normal recording operations and standby, and is opened when recovering ink from the recording head 8. The head replacement valve V5 is also opened when filling the head replacement flow path C5 with ink to fill the recording head 8.

[0059] First, a first embodiment of the recording device 1 in which a vacuum wiping process is performed as a suction process will be described with reference to FIGS. 8 to 10. As described above, the vacuum wiping process is a process in which a wiping operation is performed using the vacuum wiper unit 172. As described above, the vacuum wiping is a recovery process in which ink and foreign matter adhering to the ejection port surface 8a are wiped away by the vacuum wiper 172c while being sucked, thereby maintaining and recovering the ejection performance of each ejection port on the ejection port surface 8a. The vacuum wiping process is performed after the wiping operation by the blade wiper unit 171 in the second wiping process as described above. The vacuum wiping process is performed at a timing based on the number of conveyed sheets of the recording medium S and the elapsed time from the most recent vacuum wiping process.

[0060] 8 is a schematic diagram of the main parts of the recording head 8, the ink supply unit 15, and the vacuum wiper unit 172 of the recording apparatus 1 according to the first embodiment. As described above, the recording apparatus 1 is provided with a circulation mechanism capable of circulating ink in a flow path including the ejection ports in the recording head 8. The recording apparatus 1 is also provided with a vacuum wiper unit 172 that moves in contact with the recording head 8 to suck and wipe each ejection port on the ejection port surface 8a.

[0061] In the vacuum wiper unit 172, a carriage 172b on which a vacuum wiper 172c is mounted is slidably disposed on a guide rail 172e extending in the y direction. The carriage 172b reciprocates in the y direction by a motor 22 driven by the print controller 202 via a maintenance control unit 210. Therefore, the vacuum wiper 172c mounted on the carriage 172b is configured to be movable in the y direction via the carriage 172b. In this embodiment, the direction from the right side to the left side in FIG. 8 is the forward direction, and the direction from the left side to the right side is the return direction. In this embodiment, vacuum wiping is performed only when the vacuum wiper 172c moves in the forward direction via the carriage 172b.

[0062] The motor 22 is connected to the pulley 24 via a gear (not shown) or the like. A belt 28 is stretched between the pulley 24 and an idler pulley 26 that is disposed at a predetermined distance in the y direction. Therefore, the belt 28 rotates when driven by the motor 22. The belt 28 is arranged in parallel with the guide rail 172e so as to extend in the y direction. In addition, a carriage 172b is fixed to the belt 28. Therefore, the carriage 172b moves along the guide rail 172e as the belt 28 rotates, and the moving direction of the carriage 172b is determined by the rotating direction of the belt 28. In addition, a rotary encoder 30 capable of detecting the amount of rotation and the direction of rotation of the motor 22 is connected to the motor 22. The print controller 202 detects the moving direction and the amount of movement of the carriage 172b based on the detection result by the rotary encoder 30.

[0063] The vacuum wiper 172c has an opening 21 (see FIG. 9) capable of contacting the discharge port surface 8a and sucking the discharge port surface 8a, and is configured to be able to sequentially suck each discharge port on the discharge port surface 8a by moving in the y direction with the opening 21 in contact. The vacuum wiper 172c is connected to the suction pump 32 via a tube (not shown) or the like. A buffer tank 34 capable of reducing the pressure of the internal space by the suction pump 32 is disposed between the suction pump 32 and the vacuum wiper 172c. The buffer tank 34 is provided with a pressure sensor 36 capable of measuring the internal pressure. The print controller 202 controls the drive of the suction pump 32 via the maintenance control unit 210. At this time, the print controller 202 monitors the pressure in the buffer tank 34 by the pressure sensor 36.

[0064] In this embodiment, the vacuum wiper unit 172, the buffer tank 34, the suction pump 32, etc. function as suction means for sequentially sucking the discharge ports in the discharge port surface 8a. Also, in this embodiment, the print controller 202 (and the maintenance control unit 210) functions as a control unit for controlling the driving of the suction means, such as the movement of the carriage 172b and the driving of the suction pump 32.

[0065] Fig. 9(a) is a schematic diagram of the discharge port surface 8a of the recording head 8, and Fig. 9(b) is a partially enlarged view of frame IXb in Fig. 9(a). Fig. 9(a) shows the discharge port surface 8a as viewed from the bottom, and for ease of understanding, the wiring sealing portion and the like are omitted for simplicity.

[0066] On the discharge port surface 8a, a plurality of recording element substrates 80a, each having the same dimensions and the same configuration, are arranged along the y direction. During vacuum wiping, the print controller 202 moves the carriage 172b in the forward direction via the motor 22, and performs a suction process as a recovery process for each discharge port provided on the recording element substrate 80a. A suction preparation surface 8ab is formed on one end of the discharge port surface 8a (the right end in FIG. 9A). A vacuum wiper 172c at the vacuum wiping start position comes into contact with this suction preparation surface 8ab when vacuum wiping starts. The suction preparation surface 8ab is formed so as to be able to seal the opening 21 when it comes into contact with the vacuum wiper 172c.

[0067] The recording element substrate 80a is formed with a plurality of ejection port arrays in which ejection ports for ejecting ink are arranged. In this embodiment, the recording device 1 is assumed to perform recording using four colors of ink: black, cyan, magenta, and yellow. That is, the recording head 8 is configured to be able to perform recording by ejecting these four colors of ink onto the recording medium S. Therefore, the recording element substrate 80a is formed with ejection port arrays 85K, 85C, 85M, and 85Y corresponding to the colors black, cyan, magenta, and yellow, respectively, so as to be approximately parallel to the long side 80aa of the recording element substrate 80a.

[0068] The recording element substrate 80a is formed in the shape of a parallelogram, inclined at a predetermined angle with respect to the y direction, and arranged along the y direction with the short sides 80ab of adjacent recording element substrates 80a. Therefore, the ejection port array is also inclined at a predetermined angle with respect to the y direction, and between adjacent recording element substrates 80a, some of the ejection ports ejecting ink of the same color overlap in the y direction (see FIG. 9(b)). In this manner, in this embodiment, a long ejection port array is formed on the ejection port surface 8a by arranging a plurality of recording element substrates 80a each having a short ejection port array in parallel in the y direction. Note that the opening 21 that sucks the ejection port surface 8a in the vacuum wiper 172c includes, for example, one to several ejection ports in the y direction, and is formed to a size that includes all the ejection port arrays in the x direction.

[0069] A case where vacuum wiping is performed by the vacuum wiper unit 172 using the above configuration will be described. In the second wiping process, after the wiping process by the blade wiper unit 171, a vacuum wiping process is performed in which the vacuum wiper unit 172 performs vacuum wiping. In the following description, the vacuum wiping process will be described in detail. Note that the vacuum wiping process performed in this embodiment will be referred to as a first vacuum wiping process in the following description. FIG. 10 is a flowchart showing detailed processing contents of the first vacuum wiping process performed in the second wiping process.

[0070] When the first vacuum wiping process is started, first, the print controller 202 causes the recording head 8, which is in a position where it can come into contact with the blade wiper 171a, to retreat vertically upward from the wiping position in Fig. 4 (S1002). Next, the print controller 202 causes the wiping unit 17 housed in the maintenance unit 16 to slide and pull out to a predetermined position (S1004).

[0071] 4 by the print controller 202 (S1006). At this time, the carriage 172b is at a vacuum wiping start position on one end side in the y direction of the wiping unit 17. Then, the vacuum wiper 172c mounted on the carriage 172b comes into contact with the suction preparation surface 8ab of the ejection port surface 8a.

[0072] Next, the ink circulation is started (S1008). That is, in S1008, the print controller 202 closes the tank supply valve V1 and the head replacement valve V5 via the ink supply control unit 209, opens the atmosphere release valve V0, the supply valve V2, and the recovery valve V4, and drives the supply pump P1 and the recovery pump P2. As a result, the ink stored in the subtank 151 returns to the subtank 151 through the supply flow path C2, the recording head 8, and the recovery flow path C4 in this order. At this time, the ink is circulated in the recording head 8 so that the ink flows into the pressure chambers 1005 corresponding to all the ejection openings of the recording head 8. Note that the ink circulation in S1008 applies to each ink used in the recording device 1, that is, black ink, cyan ink, magenta ink, and yellow ink.

[0073] After the ink circulation is started in this way, the pressure in the buffer tank 34 is then reduced to a set value (S1010). That is, in S1010, the print controller 202 drives the suction pump 32 based on the detection result of the pressure sensor 36 until the pressure in the buffer tank 34 reaches the set value. The vacuum wiper 172c is connected to the buffer tank 34 by a tube or the like. Therefore, when the buffer tank 34 is reduced in pressure, a negative pressure according to the set value acts on the opening 21 that is in contact with the ejection port surface 8a. After the pressure in the buffer tank 34 is reduced to the set value, the suction pump 32 is driven to maintain the set value within a predetermined range.

[0074] Then, when the buffer tank 34 is decompressed to a set value, the vacuum wiper 172c is moved in the forward direction while in contact with the ejection port surface 8a, and vacuum wiping is performed on each ejection port of the recording element substrate 80a arranged on the ejection port surface 8a (S1012). That is, in S1012, the print controller 202 drives the motor 22 to move the carriage 172b in the forward direction, so that the vacuum wiper 172c moves in the forward direction while sucking the ejection port surface 8a at the opening 21.

[0075] Thereafter, it is determined whether the carriage 172b has moved to a preset vacuum wiping end position (S1014). That is, in S1014, the print controller 202 makes the determination based on the detection result by the rotary encoder 30. If it is determined in S1014 that the carriage 172b has moved to the vacuum wiping end position, it is determined that the vacuum wiping has ended, and the drive of the suction pump 32 and the circulation of the ink are stopped (S1016). Then, this first vacuum wiping process is ended. That is, in S1016, the print controller 202 stops the drive of the suction pump 32, the supply pump P1, and the recovery pump P2.

[0076] When the first vacuum wiping process is thus completed, the print controller 202 retracts the recording head 8 vertically upward. Then, at the timing when the vacuum wiper 172c separates from the ejection port surface 8a, the print controller 202 moves the carriage 172b in the return direction, and moves the carriage 172b to a vacuum wiping start position located on one end side in the y direction.

[0077] As described above, the recording device 1 has a circulation mechanism that circulates ink between the sub tank 151 and the flow path including the nozzles of the recording head 8. The recording device 1 also has a vacuum wiper 172c that sequentially sucks each nozzle in the nozzle surface 8a of the recording head 8. During vacuum wiping, the ink is circulated in the circulation mechanism. By circulating the ink, the ink in the nozzles is prevented from thickening in the nozzles, which are exposed to the atmosphere for a long time during vacuum wiping due to the long nozzle row. Therefore, during vacuum wiping, which maintains and restores the nozzle performance, the deterioration of the nozzle performance due to the thickening of the ink is prevented.

[0078] In addition, in the case where the ink circulation can be controlled for each recording element substrate 80a, the ink circulation may be started for each recording element substrate 80a having an ejection port for which vacuum wiping has been completed.

[0079] Second embodiment Next, a second embodiment of the recording device according to the present invention will be described with reference to Figures 11 and 12. In the following description, the same or corresponding configurations as those of the recording device 1 described above will be denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.

[0080] The recording apparatus 1 according to the second embodiment differs from the recording apparatus 1 according to the first embodiment in that, in the vacuum wiping process, ink is circulated only in a circulation path that circulates a predetermined ink.

[0081] Specifically, the recording device 1 is configured to record using black ink, cyan ink, magenta ink, and yellow ink. Of these four types of ink, ink that may change in characteristics and degrade the discharge performance at the discharge port due to continued exposure to the atmosphere while remaining in the discharge port is circulated in a circulation path during a vacuum wiping process. In this embodiment, a case will be described in which black ink is more likely to thicken and degrade the discharge performance at the discharge port than the other three inks.

[0082] Figures 11(a), (b), and (c) are diagrams showing the flow path through which ink flows near the ejection port. When ink is circulated, the circulated ink is successively exposed to the atmosphere at the meniscus of the ejection port. This causes ink components, mainly the liquid components in the ink, to evaporate from the meniscus (see Figure 11(a)). This causes ink components to continue to evaporate even in ink that continues to circulate, and there is a risk that the ink as a whole will thicken (see Figures 11(b) and (c)).

[0083] However, the black ink may thicken in the ejection port simply by remaining in the ejection port and being continuously exposed to the atmosphere, thereby deteriorating the ejection performance at the ejection port. That is, the degree of increase in viscosity of the black ink due to evaporation of ink components under predetermined conditions is greater than that of the other three inks. In order to avoid such a decrease in the ejection performance at the ejection port, the black ink is circulated during vacuum wiping. The other three inks are unlikely to thicken and degrade the ejection performance at the ejection port even if they remain in the ejection port and are continuously exposed to the atmosphere. For this reason, the cyan ink, magenta ink, and yellow ink are not circulated during vacuum wiping in order to avoid the increase in viscosity of the ink as described in FIG. 11(a), (b), and (c).

[0084] The configuration of the recording device 1 in this embodiment is the same as that of the first embodiment, so the following description will focus on the vacuum wiping process. Fig. 12 is a flowchart showing the detailed process contents of the vacuum wiping process executed in the second wiping process. Note that the vacuum wiping process executed in this embodiment is referred to as the second vacuum wiping process in the following description.

[0085] When the second vacuum wiping process is started, first, the recording head 8 is retreated vertically upward from the wiping position in Fig. 4 (S1202), and the wiping unit 17 is slid and pulled out to a predetermined position (S1204). Next, the recording head 8 is lowered to the wiping position in Fig. 4, and the vacuum wiper 172c is brought into contact with the suction preparation surface 8ab of the ejection port surface 8a (S1206). The specific process contents from S1202 to S1206 are the same as those from S1002 to S1006 described above.

[0086] Then, the circulation of black ink is started (S1208). That is, in S1208, for the blank ink circulation path, the print controller 202 closes the tank supply valve V1 and the head replacement valve V5, opens the atmosphere release valve V0, the supply valve V2 and the recovery valve V4, and drives the supply pump P1 and the recovery pump P2. Note that in this process, the valves are not opened or closed and the pumps are not driven in the circulation paths of the cyan ink, magenta ink and yellow ink.

[0087] When the circulation of the black ink is started, the pressure in the buffer tank 34 is reduced to a set value (S1210), and the vacuum wiper 172c is moved in the forward direction while being in contact with the ejection port surface 8a to perform vacuum wiping (S1212). Then, it is determined whether the carriage 172b has moved to the vacuum wiping end position (S1214). If it is determined in S1214 that the carriage 172b has moved to the vacuum wiping end position, the driving of the suction pump 32 and the circulation of the black ink are stopped (S1216), and the second vacuum wiping process is ended. Note that the specific process contents from S1210 to S1214 are the same as those from S1010 to S1014 described above. In S1216, the print controller 202 stops the driving of the suction pump 32, the supply pump P1, and the recovery pump P2 in the circulation path of the black ink.

[0088] When the second vacuum wiping process is thus completed, the recording head 8 is retreated vertically upward, and when the vacuum wiper 172c separates from the ejection port surface 8a, the carriage 172b is moved to the vacuum wiping start position.

[0089] As described above, in the recording device 1, during the vacuum wiping process, only the ink that is likely to thicken due to being retained in the ejection port and continuously exposed to the atmosphere, thereby deteriorating the ejection performance at the ejection port, is circulated. This makes it difficult for the ink that is unlikely to thicken due to being retained in the ejection port and continuously exposed to the atmosphere to thicken due to circulation, and makes it possible to maintain good ink performance.

[0090] Third embodiment Next, a third embodiment of a recording device according to the present invention will be described with reference to Figures 13 and 14. In the following description, the same or corresponding configurations as those of the recording device 1 described above will be denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.

[0091] The recording device 1 according to the third embodiment differs from the recording device 1 according to the first embodiment in the following three points. That is, the carriage 172b is slidably arranged on a guide rail 172f instead of the guide rail 172e. Two guide rails 172f are arranged to pass on both sides of the carriage 172b, so that ink does not adhere to the guide rails 172f when ink is ejected from the recording head 8. In addition, an ink receiving section 38 is provided. Furthermore, in the vacuum wiping process, instead of circulating ink, a preliminary ejection is performed to eject ink that does not contribute to image recording.

[0092] 13 is a schematic diagram of the main parts of the recording head 8, the ink supply unit 15, and the vacuum wiper unit 172 of the recording device 1 in the third embodiment. The carriages 172b are arranged at an interval in the x direction and slidably disposed on a pair of guide rails 172f extending in the y direction. In addition, an ink receiving section 38 extending in the y direction is disposed vertically below the carriage 172b. The ink receiving section 38 is a member for receiving ink preliminarily ejected from the ejection openings. The configuration of the recording device 1 in this embodiment is the same as that of the first embodiment, except for the above-mentioned guide rails 172f and the ink receiving section 38.

[0093] That is, in the recording device 1 according to the first embodiment, a vacuum wiping process that maintains and recovers the discharge performance of the discharge ports, that is, an ink circulation process is performed during a suction process to maintain and recover the discharge performance of the discharge ports. In contrast, in the recording device 1 according to the third embodiment, a preliminary discharge process that maintains and recovers the discharge performance of the discharge ports is performed during a vacuum wiping process that maintains and recovers the discharge performance of the discharge ports.

[0094] Next, the vacuum wiping process will be described. Fig. 14 is a flowchart showing the detailed process contents of the vacuum wiping process executed in the second wiping process. Note that the vacuum wiping process executed in this embodiment will be referred to as third vacuum wiping in the following description.

[0095] When the third vacuum wiping process is started, first, the recording head 8 is retreated vertically upward to the wiping position in Fig. 4 (S1402), and the wiping unit 17 is slid and pulled out to a predetermined position (S1404). Next, the recording head 8 is lowered to the wiping position in Fig. 4, and the vacuum wiper 172c is brought into contact with the suction preparation surface 8ab of the ejection port surface 8a (S1406). The specific process contents from S1402 to S1406 are the same as those from S1002 to S1006 described above.

[0096] Thereafter, the pressure in the buffer tank 34 is reduced to a set value (S1408), and the vacuum wiper 172c is moved in the forward direction while in contact with the discharge port surface 8a to perform vacuum wiping (S1410). The specific process contents of S1408 and S1410 are the same as those of S1010 and S1012 described above, respectively.

[0097] Next, a variable n representing the serial number of the recording element substrate 80a is set to "1" (S1412), and it is determined whether or not vacuum wiping of the n-th recording element substrate 80a has been completed (1414). Here, serial numbers are assigned to the multiple recording element substrates 80a arranged on the discharge port surface 8a in order from one end side where the suction preparation surface 8ab is located. In addition, each of these serial numbers is associated with and set to position information of the corresponding recording element substrate 80a. This position information is information that can be used to determine whether vacuum wiping of the recording element substrate 80a has been completed, taking into account the moving speed of the carriage 172b, etc.

[0098] Therefore, in S1414, the print controller 202 makes a judgment based on the position information associated with the serial number "n" and the detection result of the rotary encoder 30. That is, if it is judged that the carriage 172b has passed the position based on the position information associated with the nth number, it is judged that the vacuum wiping of the nth recording element substrate 80a has ended. Also, if it is judged that the carriage 172b has not passed the position based on the position information associated with the nth number, it is judged that the vacuum wiping of the nth recording element substrate 80a has not ended.

[0099] When it is determined in S1414 that the vacuum wiping of the n-th recording element substrate 80a has been completed, the n-th recording element substrate 80a starts preliminary ejection (S1416). That is, in S1416, the print controller 202 performs preliminary ejection from each ejection port of the n-th recording element substrate 80a via the head I / F 206. In this manner, in this embodiment, the print controller 202 (and the head I / F 206) functions as a control unit that controls the recording by the recording head 8. Note that, after the preliminary ejection is started, a predetermined number of ejections are continuously performed at a constant time interval. Such preliminary ejection is performed until it is determined in S1418 (to be described later) that the vacuum wiping of all the recording element substrates 80a has been completed, or in S1422 (to be described later) that the carriage 172b has moved to the vacuum wiping end position. The ink that has been preliminary ejected is received by the ink receiving unit 38.

[0100] Thereafter, it is determined whether or not vacuum wiping of all the recording element substrates 80a has been completed (S1418). That is, in S1418, it is determined whether or not vacuum wiping of the recording element substrate 80a to which the last serial number "m" has been assigned has been completed. If it is determined in S1418 that vacuum wiping of all the recording element substrates 80a has not been completed, n is incremented (S1420) and the process returns to S1414. On the other hand, if it is determined in S1418 that vacuum wiping of all the recording element substrates 80a has been completed, it is determined whether or not the carriage 172b has moved to the vacuum wiping end position (S1422).

[0101] When it is determined in S1422 that the carriage 172b has moved to the vacuum wiping end position, the preliminary discharge is ended and the driving of the suction pump 32 is stopped (S1424), and the third vacuum wiping process is ended. That is, in S1424, the print controller 202 ends the preliminary discharge on the recording element substrate 80a. The print controller 202 also stops the driving of the suction pump 32. Note that the preliminary discharge may be ended when it is determined in S1418 that the vacuum wiping on all the recording element substrates 80a is ended.

[0102] When the third vacuum wiping process is thus completed, the recording head 8 is retreated vertically upward, and when the vacuum wiper 172c separates from the ejection port surface 8a, the carriage 172b is moved to the vacuum wiping start position.

[0103] As described above, in the recording device 1, the ink is not circulated during vacuum wiping, but preliminary ejection is performed for each recording element substrate for ejection ports for which vacuum wiping has been completed during vacuum wiping. This allows the recording device 1 according to this embodiment to achieve the same effects as the recording device 1 according to the first embodiment.

[0104] (Other embodiments) The above-described embodiment may be modified as shown in the following (1) to (7).

[0105] (1) In the first embodiment, when vacuum wiping is started, the ink circulation is started in each recording element substrate 80a, but this is not limited to the above. That is, for example, by configuring the ink circulation to be controllable for each recording element substrate 80a, the ink circulation may be started in order from the recording element substrate 80a whose ejection ports have been subjected to vacuum wiping. The ink circulation for each recording element substrate 80a can be realized, for example, by providing a configuration that can selectively open and close each IN flow path corresponding to each recording element substrate 80a.

[0106] (2) In the first embodiment, ink is circulated in all of the ink circulation paths during the vacuum wiping process. In the second embodiment, ink is circulated in a specific ink circulation path during the vacuum wiping process. However, the ink circulation method is not limited to this. In other words, a configuration may be made in which, by appropriately changing, ink is circulated in all of the ink circulation paths during the vacuum wiping process, or ink is circulated only in a specific ink circulation path.

[0107] (3) In the third embodiment, preliminary ejection is performed for each recording element substrate 80a for the ejection ports for which vacuum wiping has been completed, but this is not limited to the above. That is, preliminary ejection may be performed for all recording element substrates 80a during vacuum wiping, or preliminary ejection may be performed for each ejection port for which vacuum wiping has been completed. Also, the recording device 1 in the third embodiment may be configured without including a circulation mechanism.

[0108] (4) In the above embodiment, the vacuum wiper 172c is moved relative to the discharge port surface 8a during vacuum wiping. Also, the wiping unit 17 is pulled out from the maintenance unit 16, and the recording head 8 is moved to the wiping position, so that the vacuum wiper 172c comes into contact with the discharge port surface 8a. However, the movement relationship between the recording head 8 and the vacuum wiper 172c is not limited to this. That is, any configuration may be used as long as the recording head 8 and the vacuum wiper 172c are configured to be relatively movable. Also, as long as the vacuum wiper 172c can exert sufficient suction force without coming into contact with the discharge port surface 8a, the vacuum wiper 172c may be configured to perform suction while being separated from the discharge port surface 8a.

[0109] (5) In the above embodiment, the recording device 1 is configured to record on a conveyed recording medium, but this is not limited thereto. That is, the recording device 1 may be configured to record on a recording medium placed at a predetermined position by ejecting ink from a recording head. In the above embodiment, the vacuum wiper 172c performs vacuum wiping only when it moves in the forward direction, but this is not limited thereto. That is, the vacuum wiper 172c may perform vacuum wiping only when it moves in the backward direction, or when it moves in the forward direction and the backward direction.

[0110] (6) In the second embodiment, among the multiple flow paths through which inks of different colors circulate, ink is circulated only in the flow path through which black ink circulates, but this is not limited to the above. In other words, if there are multiple flow paths through which ink that experiences a predetermined or higher degree of viscosity increase due to evaporation of ink components under predetermined conditions is circulated, ink may be circulated in the multiple flow paths.

[0111] (7) In the second embodiment, the ink is circulated in the flow path where the ink that is easily thickened circulates among the multiple flow paths, but the present invention is not limited to this. For example, JP 2018-16046 A discloses a technology for varying the diameter of the ejection port based on the brightness of the ink in order to suppress graininess in the recorded image. If the diameter of the ejection port is small, the ejection performance of the ejection port is likely to decrease due to the thickening of the ink. For this reason, in a recording head formed with different ejection port diameters, at least in the flow path that ejects ink from an ejection port with a diameter smaller than a predetermined diameter, the ink may be configured to circulate during vacuum wiping. [Explanation of symbols]

[0112] 8. Recording Head 8a Discharge port surface 15 Ink supply unit 172 Vacuum wiper unit 202 Print Controller

Claims

1. a recording head including a plurality of ejection ports for ejecting ink, recording elements for ejecting ink from the ejection ports, pressure chambers communicating with the ejection ports provided at positions corresponding to the recording elements and corresponding to each of the ejection ports with which the ejection ports communicate, a first flow path capable of supplying ink to the pressure chambers, and a second flow path capable of recovering ink from the pressure chambers; a suction unit that faces an ejection port surface of the recording head on which the plurality of ejection ports are formed and performs a suction process for sucking ink from the ejection ports; a circulation unit that circulates the ink so that the ink flows from the first flow path through the pressure chamber to the second flow path without being discharged from the ejection port, The ink jet recording apparatus according to claim 1, wherein the circulating means circulates the ink during the suction process by the suction means.

2. the recording head ejects a plurality of types of ink from different ejection ports; the ejection ports for the plurality of types of ink each have a different first flow path, a different pressure chamber, and a different second flow path; the circulation means is capable of circulating ink such that the ink flows from the first flow path through the pressure chamber to the second flow path without being discharged from the ejection port, for each of the plurality of types of ink; 2. The ink jet recording apparatus according to claim 1, wherein the circulating means circulates the ink during the suction process by the suction means.

3. The inkjet recording device described in Claim 2, characterized in that the circulation means circulates ink whose degree of viscosity increase due to evaporation of liquid components in the ink under specified conditions is equal to or greater than a specified level during the suction process by the suction means.

4. 4. The ink jet recording apparatus according to claim 2, wherein the circulation means circulates at least one type of ink during the suction process by the suction means.

5. 5. The ink jet recording apparatus according to claim 2, wherein the pressure chambers provided in correspondence with a plurality of the ejection ports ejecting the same type of ink are in communication with each other.

6. the recording head has an ejection port having a predetermined diameter and an ejection port having a diameter smaller than the predetermined diameter, 3. The ink jet recording apparatus according to claim 1, wherein the circulation means circulates the ink ejected from the ejection ports having a diameter smaller than the predetermined diameter during the suction process by the suction means.

7. An inkjet recording apparatus according to any one of claims 1 to 6, characterized in that during the suction process by the suction means, the circulation means circulates ink so that it flows from the first flow path through the pressure chamber to the second flow path for the pressure chambers provided corresponding to all of the ejection ports of the recording head.

8. 7. The inkjet recording apparatus according to claim 1, wherein the recording head includes a plurality of substrates arranged side by side, each substrate having a plurality of ejection ports and a plurality of pressure chambers provided corresponding to the ejection ports.

9. 9. The inkjet recording apparatus according to claim 1, wherein the suction means performs the suction process by moving relatively to the ejection port surface while in contact with the ejection port surface, and sequentially sucking the ejection ports.

10. a third flow path that supplies ink from a storage portion that stores ink to the recording head; a fourth flow path; the fourth flow path is provided such that ink that has passed through the third flow path and the recording head passes through the fourth flow path and then passes through the third flow path again; 10. The inkjet recording apparatus according to claim 1, wherein the circulation means circulates the ink through the third flow path, the fourth flow path, the first flow path provided in the recording head, the pressure chamber, and the second flow path.

11. 11. The ink jet recording apparatus according to claim 10, further comprising a plurality of the third flow paths and a plurality of the fourth flow paths.

12. the recording head ejects a plurality of types of ink from different ejection ports; 12. The ink jet recording apparatus according to claim 11, wherein the third flow path and the fourth flow path are provided for each type of ink.

13. An inkjet recording device described in any one of claims 1 to 12, characterized in that the multiple ejection ports of the recording head are arranged in the width direction of the recording medium on which an image is recorded, for a length corresponding to the width of the recording medium.

14. A recovery method for a recording head comprising a plurality of ejection ports for ejecting ink, a recording element for ejecting ink from the ejection ports, pressure chambers communicating with the ejection ports provided at positions corresponding to the recording elements and corresponding to each of the communicating ejection ports, a first flow path capable of supplying ink to the pressure chambers, and a second flow path capable of recovering ink from the pressure chambers, the method comprising the steps of: sucking ink from the ejection ports by a suction means; A recovery method characterized by circulating ink so that it flows from the first flow path through the pressure chamber to the second flow path without discharging ink from the ejection port during suction processing by the suction means.

15. The recording head comprises: A plurality of types of ink are ejected from different ejection ports, the first flow path, the pressure chamber, and the second flow path, each of which has a different ejection port for each of the plurality of types of ink; The recovery method according to claim 14, characterized in that during the suction process by the suction means, the ink is circulated so that the ink flows from the first flow path through the pressure chamber to the second flow path without discharging the ink from the ejection port for the plurality of types of ink.

16. A recovery method as described in Claim 15, characterized in that the ink circulating during the suction process by the suction means is ink whose degree of viscosity increase due to evaporation of liquid components in the ink under specified conditions is greater than or equal to a specified level.

17. the recording head has the ejection port having a predetermined diameter and the ejection port having a diameter smaller than the predetermined diameter, 16. The recovery method according to claim 14, further comprising circulating the ink ejected from the ejection port having a diameter smaller than the predetermined diameter during the suction process by the suction means.

18. A recovery method according to any one of claims 14 to 17, characterized in that during the suction process by the suction means, ink is circulated so that it flows from the first flow path through the pressure chamber to the second flow path for the pressure chambers provided corresponding to all of the ejection ports of the recording head.

19. 18. The recovery method according to claim 14, wherein the recording head includes a plurality of substrates arranged side by side, on which a plurality of the ejection ports and the pressure chambers provided corresponding to the ejection ports are arranged.

20. a third flow path that supplies ink from a storage portion that stores ink to the recording head; a fourth flow path; the fourth flow path is provided such that ink that has passed through the third flow path and the recording head passes through the fourth flow path and then passes through the third flow path again; 20. The method of claim 14, wherein during the suction process, ink is circulated through the third flow path, the fourth flow path, the first flow path provided in the recording head, the pressure chamber, and the second flow path.

21. The recovery method according to claim 20, characterized in that the third flow path and the fourth flow path are provided in plurality.

22. The recording head ejects a plurality of types of ink from different ejection ports, 22. The recovery method according to claim 21, wherein the third flow path and the fourth flow path are provided for each type of ink.

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