Liquid discharge apparatus and control method

Abstract

To provide a technique for suppressing drying of liquid in a liquid discharge part when the liquid discharge part is capped.SOLUTION: According to an aspect of the present invention, there is provided a liquid discharge apparatus including a cap unit configured to cover a discharge port surface provided with a discharge port of a discharge unit configured to discharge a liquid and to cap the discharge port surface, and a circulation unit configured to circulate the liquid in a circulation path including a storage unit configured to communicate with the discharge port of the discharge unit and to store the liquid discharged from the discharge port, wherein the circulation unit performs an operation of circulating the liquid in the circulation path in a state in which the cap unit covers the discharge port surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection apparatus and a control method. [Background technology]

[0002] Inkjet recording devices are known as devices that eject liquid. In inkjet recording devices, ink can dry out in the ejection nozzles that eject ink, causing the ink to thicken and stick. Patent Document 1 discloses a method of agitating and shaking the ink while the nozzle opening is capped with a cap that holds an ink absorption sheet, thereby preventing the ink at the nozzle tip from drying out or thickening. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-264348 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, for example, when the cap is opened during a recording operation, the ink absorbed in the ink absorption sheet inside the cap evaporates, which can leave absorbent components in the ink absorption sheet. If the ejection head is then capped again in this state, the components remaining in the ink absorption sheet can absorb the moisture in the ink in the ejection nozzles, causing the ink in the ejection nozzles to dry out. Therefore, when the liquid ejection unit is capped, a method is needed to prevent the liquid in the liquid ejection unit from drying out.

[0005] An object of the present invention is to provide a technique for preventing the liquid in a liquid ejection section from drying out when the liquid ejection section is capped. [Means for solving the problem]

[0006] According to the present invention, A liquid ejection device, a capping means for covering a discharge port surface on which a discharge port of a discharge means for discharging a liquid is provided, and capable of capping the discharge port surface; a circulation means that communicates with the discharge port of the discharge means and circulates the liquid through a circulation path that includes a storage section that stores the liquid to be discharged from the discharge port, the circulation means performs an operation of circulating the liquid through the circulation path while the cap means is covering the discharge port surface. A liquid ejection device characterized by the above features is provided. [Effects of the Invention]

[0007] According to the present invention, when the liquid ejection section is capped, it is possible to prevent the liquid in the liquid ejection section from drying out. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram illustrating a partial configuration of a recording apparatus. [Figure 2] FIG. 2 is a schematic diagram of a recording head of the recording apparatus. [Figure 3] FIG. 2 is a cross-sectional view of a recording head of the recording apparatus. [Figure 4] FIG. 2 is a block diagram illustrating a control system of the printing apparatus. [Figure 5] 10 is a flowchart showing a capping process. [Figure 6] 10 is a flowchart showing a moisturizing process. [Figure 7] 10A and 10B are schematic diagrams illustrating the configuration of another leaving cap mechanism. [Figure 8] 10 is a flowchart showing a capping process. [Figure 9] 10 is a flowchart showing a moisturizing process. [Figure 10] FIG. 2 is a diagram illustrating a partial configuration of a recording apparatus. [Figure 11] FIG. 10 is a diagram showing another example of a dry cap. [Figure 12]FIG. 1 is a perspective view showing the appearance of a liquid ejection device. [Figure 13] FIG. 2 is a block diagram showing the configuration of a recording control system in the recording apparatus. [Figure 14] FIG. 2 is a diagram showing an example of a configuration of a print head and a group of ejection openings. [Figure 15] FIG. [Figure 16] FIG. 2 is a perspective view showing a recovery unit. [Figure 17] FIG. 2 is a diagram showing a recording head and a wiper. [Figure 18] FIG. 2 is a schematic diagram showing the configuration of a print head and a buffer tank. [Figure 19] FIG. 3 is a cross-sectional view showing a discharge port, a common flow path, and a recovery flow path. [Figure 20] FIG. 2 is a plan view showing the outlet, the inlet, and the outlet. [Figure 21] FIG. 2 is a perspective view showing a leaving unit. [Figure 22] FIG. 10 is a diagram showing the positional relationship between a recovery unit and an idle unit. [Figure 23] 10 is a graph showing the change in relative humidity inside the storage cap. [Figure 24] 10 is a flowchart showing humidification control in the leaving cap. [Figure 25] 10 is a graph showing the change in relative humidity inside the storage cap. [Figure 26] 10 is a flowchart showing a process for selecting the humidification control and recovery circulation times. [Figure 27] FIG. 10 is a diagram showing a recovery circulation time selection table. [Figure 28] 10 is a flowchart showing humidification control in the leaving cap. [Figure 29] 10A and 10B are diagrams illustrating an example of detecting an ink adhesion rate and a table for selecting an upper limit number of times. [Figure 30] 10 is a graph showing the transition of the moisture evaporation rate of adhered dried ink. [Figure 31] 10 is a flowchart showing humidification control in the leaving cap. [Figure 32] FIG. 32 shows a table referred to in the flowchart of FIG. 31. [Figure 33] 10 is a flowchart showing the control of humidifying the inside of the cap. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] First Embodiment Please refer to Figures 1 and 10. Figure 1 is a partially enlarged view of a liquid ejection device 1 according to one embodiment of the present invention. Figure 10 corresponds to a partial plan view of the liquid recording device 1. In each figure, arrows X, Y, and Z indicate directions that intersect with each other, and in this embodiment, are perpendicular to each other. When the liquid ejection device 1 is installed on a horizontal surface, the left-right direction is the X direction, the front-back direction is the Y direction, and the up-down direction is the Z direction. The X direction and Y direction can also be called lateral directions.

[0011] The liquid ejection device 1 of this embodiment will be described below. In the following description, the liquid ejection device 1 will be an inkjet recording device (hereinafter referred to as recording device) that ejects ink onto a recording medium to record.

[0012] "Recording" not only includes the formation of meaningful information such as characters and figures, but also includes the formation of images, patterns, designs, etc. on a recording medium, whether meaningful or insignificant, or the processing of the medium, regardless of whether it is manifested in a way that can be perceived visually by humans. In addition, although sheet-like paper is assumed as the "recording medium" in this embodiment, it may also be cloth, plastic film, etc.

[0013] 1, the recording apparatus 1 includes a transport unit 2 that transports a recording medium. The transport unit 2 includes a transport roller 20 that transports the recording medium, and a plurality of pinch rollers 21 that are driven by the transport roller 20. The recording apparatus 1 also includes a platen 22 that supports the recording medium transported by the transport roller 20 (see FIG. 10).

[0014] The recording device 1 also includes a recording head 3 that ejects ink, which is a recording material, onto a recording medium transported by a transport unit 2 to record an image. The recording head 3 is disposed opposite a platen 22 (see FIG. 10). An image is recorded on the recording medium by ejecting ink from the recording head 3 onto the recording medium transported above the platen 22. In other words, the recording head 3 is an ejection head that ejects liquid. The recording head 3 also includes an ejection surface 30 that faces the recording medium, and ejection ports 31 provided in the ejection surface 30. In other words, the ejection ports 31 are ejection nozzles.

[0015] The print head 3 has ejection energy generating elements 32, such as electrothermal conversion elements (heaters) or piezoelectric elements, and ejects ink from the ejection orifices 31. For example, when an electrothermal conversion element is used as the ejection energy generating element 32, the heat generated by the element causes the ink to bubble, and the resulting bubble-generating energy can be used to eject ink from the ejection orifices 31. The print head 3 uses a serial scan printing method. In the serial scan method, the print head 3 is mounted on a carriage 40, which will be described later, and moves back and forth in the X direction. Ejecting ink while moving the print head 3 in the X direction is called a print scan. An image is printed on the print medium by alternately repeating the print medium transport operation and the print scan of the print head 3.

[0016] The recording device 1 includes a moving unit 4 that moves the recording head 3 back and forth in the X direction. The moving unit 4 includes a carriage 40 on which the recording head 3 is detachably mounted, a guide shaft 41 that supports the carriage 40 so that it can move in the X direction, and a timing belt 42 that is arranged along the X direction. The carriage 40 is connected to the timing belt 42. The moving unit 4 also includes a motor pulley 43 that rotates the timing belt 42, and an idler pulley 44 that faces the motor pulley 43 and suspends the timing belt 42 while applying tension to it. The moving unit 4 moves the carriage 40, on which the recording head 3 is mounted, back and forth in the X direction by rotating the timing belt 42 due to the drive of a CR (carriage) motor 113, which will be described later.

[0017] The recording apparatus 1 includes a dry cap mechanism 5 that caps the recording head 3. Covering the ejection surface 30 of the recording head 3 is sometimes called "capping." The dry cap mechanism 5 includes a dry cap 50, a communication passage 51, a pressing unit 52, a transmission unit 53, a lifting member 54, and the like.

[0018] The dry cap 50 is a storage cap that covers the ejection surface 30 of the recording head 3 when the recording head 1 is left unused. In other words, the dry cap 50 is a cap that covers the ejection surface 30 of the recording head 3 when the recording device 1 is not performing a recording operation or a maintenance operation. In other words, the dry cap 50 can also be said to be a cap that prevents ink from being ejected from the recording head 3.

[0019] The dry cap 50 is made of, for example, rubber. Unlike the suction cap 60 described below, the dry cap 50 is a cap that does not include an absorber 600 that absorbs ink. In other words, when the dry cap 50 covers the ejection surface 30, it does not suction ink from the ejection surface 30; in other words, it is a cap that is not connected to a suction unit.

[0020] The communication passage 51 is connected to the dry cap 50 and connects the dry cap space 5S formed by the dry cap 50 covering the ejection surface 30 with the external space. The communication passage 51 may be, for example, a tube. The dry cap 50 is also formed with a through-hole 510 that passes through between the dry cap space 5S side and the external space side, and the through-hole 510 is also included as part of the communication passage 51 (see FIG. 2).

[0021] The pressing portion 52 is, for example, an elastic body such as a spring, and presses the dry cap 50 when the dry cap 50 covers the ejection surface 30. The transmission portion 53 is a plate that transmits the driving force of the lifting member 54 to the pressing portion 52.

[0022] The lifting member 54 is, for example, a cam that rotates about an axis in the Y direction to lift and lower the dry cap 50 in the height direction (Z direction) of the recording device 1. Note that the lifting member 54 may be, for example, a cam that acts in conjunction with the rotation about an axis in the X direction to lift and lower the dry cap 50. The lifting member 54 is not limited to a cam, and may also be a linear actuator, a solenoid, a cylinder, or the like.

[0023] The recording apparatus 1 includes a suction cap mechanism 6 used for maintenance operations, which will be described later. The suction cap mechanism 6 includes, for example, a suction cap 60, a communication unit 61, a pressing unit 62, a transmission unit 63, a lifting member 64, and a suction unit 65.

[0024] The suction cap 60 is a cap used during maintenance of the recording head 3. The suction cap 60 is made of, for example, rubber. The suction cap 60 includes an absorber 600 therein that absorbs ink ejected from the recording head 3.

[0025] The communication unit 61 includes a communication passage 611 that connects the suction cap space formed when the suction cap 60 covers the discharge surface 30 with the outside space. The communication passage 611 may be, for example, a tube. The communication unit 61 also includes an on-off valve 610 that is provided in the communication passage 611 and opens and closes the communication passage 611.

[0026] The pressing portion 62 is, for example, an elastic body such as a spring, and presses the suction cap 60 when the suction cap 60 covers the ejection surface 30. The transmission portion 63 is a plate that transmits the driving force of the lifting member 64 to the pressing portion 62.

[0027] The lifting member 64 is, for example, a cam, which rotates around an axis in the Y direction to lift and lower the suction cap 60 in the height direction (Z direction) of the recording device 1. Note that the lifting member 64 may also be configured to lift and lower the suction cap 60 using a cam that acts in conjunction with the operation of rotating around an axis in the X direction. Furthermore, the lifting member 64 is not limited to a cam, and may also be a linear actuator, a solenoid, a cylinder, or the like.

[0028] During a maintenance operation, which will be described later, the suction unit 65 creates a negative pressure in the suction cap space and sucks ink from the recording head 3 via the absorber 600. The suction unit 65 includes a communication passage 650 that connects the suction cap space to the outside space. The communication passage 650 is, for example, a suction tube connected to the suction cap 60. The suction unit 65 includes a suction pump 651 that creates a negative pressure in the suction cap space via the communication passage 650. In other words, the suction pump 651 is a decompression pump that decompresses the suction cap space.

[0029] The recording apparatus 1 also includes a waste liquid tank 7 that stores waste ink ejected from the recording head 3 by creating a negative pressure in the suction cap space with the suction unit 65.

[0030] <Recording operation> Next, a description will be given of the recording operation of the recording device 1. When the recording device 1 receives a recording operation command, the recording medium is sandwiched between the conveying roller 20 and the pinch roller 21, and a part of the recording medium is conveyed to a position facing the recording head 3.

[0031] Next, the recording device 1 drives the lifting member 54 to lower the dry cap 50 in the direction opposite to the Z direction, thereby opening the dry cap 50. Then, the recording device 1 ejects ink from the ejection openings 31 while scanning the carriage 40, which carries the recording head 3, back and forth in the X direction perpendicular to the conveyance direction of the recording medium, thereby performing a recording operation for one line on the recording medium.

[0032] The recording device 1 performs a conveying operation for one line of the recording medium by rotating the conveying roller 20 in the direction of arrow A in Fig. 1. The recording device 1 then repeats the recording operation and conveying operation for the required number of times. After completing recording on the recording medium, the recording device 1 ejects the recording medium to an ejection unit (not shown) such as a tray.

[0033] When the recording operation is completed, the recording device 1 moves the carriage 40 to a position facing the dry cap 50 (above the dry cap 50). This completes a series of recording operations by the recording device 1. Thereafter, the recording device 1 drives the lifting member 54 to raise the dry cap 50, and brings the dry cap 50 into contact with the ejection surface 30 to cap the recording head 3. The operation of the recording device 1 when capping the recording head 3 with the dry cap 50 will be described later (see FIGS. 5 and 6).

[0034] <Maintenance operation> Next, a description will be given of the maintenance operation of the recording head 3. The recording device 1 performs maintenance operations to maintain good ink ejection performance of the recording head 3. Maintenance operations include, for example, a suction operation by the suction unit 65 performed to fill the recording head 3 with ink, and a preliminary ejection operation performed during maintenance of the recording head 3 or before performing a recording operation. The recording device 1 can prevent ink from clogging the ejection ports 31 of the recording head 3, etc., through the maintenance operation.

[0035] For example, when performing a suction operation as a maintenance operation, the recording device 1 moves the carriage 40 to move the recording head 3 to a position facing the suction cap 60 (above the suction cap 60).The recording device 1 then drives the lifting member 64 to raise the suction cap 60 in the Z direction, and caps the recording head 3 by bringing the suction cap 60 into contact with the ejection surface 30.

[0036] Next, the recording apparatus 1 closes the on-off valve 610 and drives the suction pump 651 to create a negative pressure in the suction cap space surrounded by the suction cap 60 and the recording head 3 , thereby sucking ink from the ejection ports 31 of the recording head 3 .

[0037] Next, the recording apparatus 1 uses the suction pump 651 to suck out the waste ink discharged into the suction cap 60 into the waste liquid tank 7, while opening the on-off valve 610 with the ejection surface 30 capped with the suction cap 60. This allows air to enter the suction cap space from the external space through the communication passage 611, replacing the waste ink in the suction cap space with air. The sucked out waste ink is stored in the waste liquid tank 7.

[0038] Then, the recording apparatus 1 drives the lifting member 64 to lower the suction cap 60 in the direction opposite to the Z direction, opens the suction cap 60, and wipes the ejection surface 30 of the recording head 3 with a wiper blade (not shown). This completes the suction operation.

[0039] Next, the preliminary ejection operation will be described. When performing the preliminary ejection operation, the recording device 1 moves the recording head 3 to a position facing the suction cap 60 with the suction cap 60 open. The recording device 1 ejects ink from the recording head 3 and receives the ejected waste ink with the suction cap 60. Then, when the preliminary ejection is completed, the recording device 1 drives the suction pump 651 with the open / close valve 610 open to store the waste ink in the waste liquid tank 7.

[0040] Here, the absorber 600 is used in both the suction operation and the preliminary ejection operation. For example, in the suction operation and the preliminary ejection operation, the capillary force of the absorber 600 is utilized when the ink ejected from the recording head 3 to the suction cap 60 is discharged into the waste liquid tank 7 by driving the suction pump 651. Furthermore, the ink ejected from the recording head 3 is absorbed by the absorber 600. This prevents the ink ejected onto the suction cap 60 from bouncing off the suction cap 60 and adhering to the ejection surface 30.

[0041] However, in practice, when the waste ink absorbed in the absorber 600 is discharged into the waste liquid tank 7 by the suction unit 65, a small amount of waste ink remains in the absorber 600. For example, if the suction cap 60 is opened to perform a recording operation of the recording device 1 while waste ink remains in the absorber 600, the absorber 600 is exposed to the atmosphere. That is, during the recording operation, the absorber 600 is in contact with air. When the absorber 600 is exposed to the atmosphere in this manner, the moisture contained in the waste ink remaining in the absorber 600 evaporates. As a result, residual components such as non-volatile solvent components and solid components contained in the waste ink remain in the absorber 600. Furthermore, such residual components may contain solvent components with water-absorbing properties.

[0042] Here, for example, assume that the recording head 3 is capped with the suction cap 60 and left as is. In such a case, the water-absorbent solvent component remaining in the absorber 600 acts as a water absorbent material and absorbs the moisture in the ink from the ejection ports 31 of the recording head 3. As a result, the ink in the recording head 3 may become viscous or solidify due to drying.

[0043] Also, for example, when the recording head 3 is capped with the suction cap 60 and left standing, it is assumed that ink is ejected from the recording head 3 to moisten the absorber 600 in order to prevent the solvent component from acting as a water absorbent. In this case, extra ink will be consumed. Also, it will be necessary to enlarge the waste liquid tank.

[0044] Also, assume that the recording device 1 has a mechanism for sending water vapor generated by moisturizing liquid into the space inside the cap. In such a case, the configuration of the recording device 1 becomes large-scale, and moisturizing liquid is used as a consumable item in addition to ink.

[0045] Therefore, a method is required to prevent the ink from drying out in the recording head 3 when the recording head 3 is left unused. In this embodiment, when the recording head 3 is left unused, the recording device 1 covers the ejection surface 30 with a dry cap 50 that does not include an absorber 600 for receiving ink. Furthermore, with the ejection surface 30 covered with the dry cap 50, the recording device 1 circulates the ink in the recording head 3 using a circulation unit 9, which will be described later. With this configuration, when the recording head 3 is capped, the ink in the recording head 3 is not absorbed by residual components remaining in the absorber 600. Furthermore, as will be described later, circulating the ink in the recording head 3 maintains a high humidity level in the dry cap space 5S, thereby preventing the ink from drying out on the ejection surface 30. In other words, the ink in the recording head 3 can be prevented from drying out.

[0046] <Capping and circulation operation> Next, the capping operation of the recording head 3 by the dry cap 50 and the circulation operation by the circulation unit 9 will be described.

[0047] 2 is a schematic diagram for explaining the inside of the recording head 3 in this embodiment. In FIG. 2, the inside of the recording head 3 attached to the carriage 40 is indicated by a dotted line (similar to FIG. 1).

[0048] The recording device 1 includes a storage section 8 and a circulation unit 9. The storage section 8 is a sub-tank that stores ink supplied from an ink tank (not shown). The circulation unit 9 communicates with the ejection ports 31 and circulates the ink through a circulation path 90 that includes the storage section 8 that stores the ink to be ejected from the ejection ports 31. Specifically, the circulation unit 9 performs a circulation operation of circulating the ink through the circulation path 90 while the dry cap 50 covers the ejection surface 30, as will be described later.

[0049] The circulation unit 9 includes an on-off valve 91 that opens and closes the circulation path 90, and a circulation pump 92 that circulates ink through the circulation path 90. The pressure of the ink in the ink container 8 is adjusted by opening and closing the on-off valve 91 and driving the circulation pump 92. The circulation path 90 also includes a flow path formed between the ink container 8 and the ejection opening 31 via the on-off valve 91, and a flow path formed between the ejection opening 31 and the ink container 8 via the circulation pump 92. The ink container 8 is also included as part of the circulation path 90. In a circulation operation described below, for example, the recording apparatus 1 can circulate the ink in the recording head 3 through the circulation path 90 in the direction B in the figure by driving the circulation pump 92.

[0050] Here, the state of ink inside the recording head 3 will be described with reference to Fig. 3. Fig. 3 is a schematic diagram showing the inside of the recording head 3, and corresponds to an enlarged view of the periphery of the ejection port 31. Fig. 3 shows a state in which an ink meniscus M is formed at the ejection port 31 due to the surface tension of the ink. Note that, for example, when the ejection surface 30 is viewed from below (the recording medium side), the shape of the ejection port 31 is circular.

[0051] The recording device 1 drives the circulation pump 92 to circulate the ink in the circulation path 90. That is, the ink flows within the recording head 3. The circulation pump 92 causes the ink to flow within the circulation path 90 so that the pressure is stronger than the set pressure of the on-off valve 91. As a result, the ink at the ejection port 31 is under negative pressure, and the meniscus M formed at the ejection port 31 is concave toward the outside of the ejection port 31. During the circulating operation, the ink flows along the streamlines shown in FIG. 3. Due to this circulating operation, the meniscus M is formed at the ejection port 31 by the ink supplied from the storage section 8.

[0052] Here, we will explain an example of covering the ejection surface 30 with a dry cap 50 to cap the ejection orifices 31. As described above, the dry cap 50 does not include an absorber 600 for receiving ink. Therefore, unlike the suction cap 60, residual components of the waste ink absorbed by the absorber 600 do not remain. Therefore, moisture in the ink in the print head 3 is not absorbed by water-absorbent solvents or the like. However, when the ejection orifices 31 are covered with the dry cap 50, the ink meniscus M is exposed to the air in the dry cap space 5S. For example, if the relative humidity of the air in the dry cap space 5S is below the saturated water vapor pressure, water vapor from the ink continues to be released from the meniscus M until the saturated water vapor pressure is reached. Furthermore, for example, if ink is not supplied from the ink container 8 to the ejection orifices 31, the moisture in the ink evaporates from the meniscus M, causing the ink near the ejection orifices 31 to dry out, potentially resulting in thickening and solidification.

[0053] Therefore, in this embodiment, with the ejection port 31 covered with the dry cap 50, the humidity in the dry cap space 5S is increased by circulation operation, and the ink is left in a state close to saturated water vapor pressure, thereby preventing the ink from drying out at the ejection port 31.

[0054] That is, when the recording head 3 is capped with the dry cap 50, ink that is contained in the container 8 and contains a sufficient amount of water is supplied by circulation, thereby releasing water from the meniscus M. This brings the pressure inside the dry cap space 5S closer to saturated water vapor pressure. By bringing the pressure inside the dry cap space 5S closer to saturated water vapor pressure, it is possible to prevent water from evaporating from the surface of the meniscus M. Furthermore, once the dry cap space 5S is brought to a high humidity state by this operation, the high humidity state is maintained even after the circulation of the ink is stopped.

[0055] The dry cap 50 is provided with a communication path 51. For example, if the dry cap space 5S is completely sealed, the air in the dry cap space 5S may expand or contract due to changes in the temperature or air pressure in the environment in which the recording apparatus 1 is installed. As a result, air may be forced into the ejection ports 31, or ink may be drawn out from the ejection ports 31. Therefore, the pressure in the dry cap space 5S is equalized with the pressure in the external space via the communication path 51, preventing changes in the pressure in the dry cap space 5S when the dry cap 50 caps the ejection ports 31.

[0056] The communicating passage 51 is made long in order to prevent a decrease in humidity in the dry cap space 5S when the dry cap 50 caps the ejection surface 30. For example, the communicating passage 51 may be configured to be longer than the communicating passage 611. Furthermore, for example, the communicating passage 51 may be configured so that the inner diameter of the communicating passage 51 is smaller than the inner diameter of the communicating passage 611.

[0057] Note that the humidity in the dry cap space 5S may decrease over time depending on the water vapor permeability of the dry cap 50, etc. Therefore, in order to prevent the humidity in the dry cap space 5S from decreasing, the ink is circulated when a predetermined time has elapsed since the dry cap 50 capped the ejection surface 30, thereby increasing the humidity in the dry cap space 5S. By performing such periodic circulation operation, it is possible to prevent the ink from drying out at the ejection ports 31, even when the recording head 3 is left unused for a long period of time.

[0058] Next, reference is made to Fig. 4. Fig. 4 is a block diagram showing the control system and each piece of hardware of the recording device 1.

[0059] The recording device 1 includes a CPU 101 that controls the overall operation of the recording device 1, such as the operation of each component and data processing, and a ROM 102 that stores various programs and data executed by the CPU 101. The recording device 1 also includes a RAM 103 that temporarily stores processing data and the like executed by the CPU 101. The recording device 1 also includes an external interface 104. The external interface 104 is connected to, for example, an external device (not shown) and receives recording data and various commands from the external device.

[0060] The recording apparatus 1 includes a timer 105 for measuring time. In the process described below, the CPU 101 uses the timer 105 to measure the time from when the ink circulation starts, the time from when the ink circulation stops, and the like.

[0061] The recording apparatus 1 includes a pump driver 106 that controls the driving of the circulation pump 92, and a cam motor driver 107 that controls the driving of the lifting member 54. The pump driver 106 is connected to the circulation pump 92 and controls the driving of the circulation pump 92. The cam motor driver 107 is connected to a cam motor 111 that drives the lifting member 54 and controls the driving of the cam motor 111. The recording apparatus 1 also includes a cam motor driver 108. The cam motor driver 108 is connected to a cam motor 112 that drives the lifting member 64 and controls the driving of the cam motor 112.

[0062] The recording apparatus 1 also includes a CR motor driver 109 that controls the driving of the CR motor, an LF motor driver 110 that controls the driving of the LF motor driver 110, a humidity sensor 10, and the like.

[0063] Next, reference is made to FIG. 5. FIG. 5 is a flowchart showing an example of an idle capping process that is executed when the recording head 3 is left idle. The process of FIG. 5 may be started, for example, after the recording device 1 has finished a recording operation. The process of FIG. 5 may also be started, for example, after a maintenance operation for the recording head 3 has finished. The process of FIG. 5 is realized, for example, by the CPU 101 reading a program stored in the ROM 102, which is a computer-readable recording medium, into the RAM 103 and executing the program.

[0064] In S101, the CPU 101 covers the ejection surface 30 with the dry cap 50. In other words, the CPU 101 caps the print head 3 with the dry cap 50. Specifically, for example, the CPU 101 drives the cam motor 111 via the cam motor driver 107 to rotate the lifting member 54, which is a cam. This process causes the dry cap 50 to rise in the Z direction, and the ejection surface 30 is covered with the dry cap 50. In this way, by covering the ejection surface 30 with a dry cap that does not have an absorber 600 for receiving ink, it is possible to prevent the ink in the print head 3 from being absorbed by components such as solvent remaining in the absorber 600.

[0065] In S102, the CPU 101 performs a circulation operation to circulate the ink in the print head 3. Specifically, for example, the CPU 101 controls the pump driver 106 to drive the circulation pump 92 and circulate the ink in the circulation path 90. This process causes water vapor to be released from the meniscus M into the dry cap space 5S, thereby increasing the humidity in the dry cap space 5S and preventing the ink in the print head 3 from drying out.

[0066] In S103, the CPU 101 determines whether the time elapsed since the start of the circulation operation has exceeded time T1. If the CPU 101 determines that time T1 has been exceeded, the process proceeds to S104. On the other hand, if the CPU 101 determines that time T1 has not been exceeded, the process repeats S103. In this embodiment, the recording apparatus 1 sets the lapse of a predetermined time T1 since the start of the circulation operation as a condition for stopping the circulation operation. That is, in this embodiment, the recording apparatus 1 performs management to increase the humidity in the dry cap space 5S to a target value based on the time elapsed since the start of ink circulation.

[0067] In this embodiment, the CPU 101 manages the humidity in the dry cap space 5S to reach the target value by continuing the circulation of ink for a predetermined time T1. In other words, the circulation operation is stopped based on conditions related to humidity changes in the dry cap space 5S. The CPU 101 acquires data on the time from when the circulation starts until the target humidity is reached based on the humidity and temperature of the environment in which the recording apparatus 1 is installed and the capacity of the dry cap space 5S, and sets the time T1.

[0068] In S104, the CPU 101 stops the circulation operation by the circulation unit 9. Specifically, the CPU 101 stops driving the circulation pump 92 via the motor driver. As a result of the processing up to this point, the inside of the dry cap space 5S reaches the target humidity.

[0069] In S105, the CPU 101 drives the timer 105 and starts counting the stop time since the circulation operation was stopped. For example, the humidity in the dry cap space 5S may gradually decrease after the circulation operation is stopped. Therefore, in this embodiment, if a printing operation command is not received within a predetermined time after the circulation operation is stopped, the stop time is counted in order to execute the circulation operation again. With this, the CPU 101 ends the idle capping processing operation.

[0070] Next, reference is made to FIG. 6. FIG. 6 is a flowchart showing an example of a moisturizing process during standing. This process is executed to restore the target humidity level when the humidity in the dry cap space 5S drops while the print head 3 is left standing with the dry cap 50 capped. The process of FIG. 6 is started, for example, when the CPU 101 ends the process of FIG. 5. The process of FIG. 6 is realized, for example, by the CPU 101 reading a program stored in the ROM 102, which is a computer-readable recording medium, into the RAM 103 and executing it.

[0071] In S201, the CPU 101 determines whether the time that has elapsed since the circulation operation was stopped exceeds time T2 based on the stop time measured by the timer 105. If the CPU 101 determines that time T2 has been exceeded, the process proceeds to S203. On the other hand, if the CPU 101 determines that time T2 has not been exceeded, the process proceeds to S202. In this embodiment, the circulation operation is resumed when a predetermined time T2 has elapsed since the circulation operation was stopped due to the elapse of a predetermined time T1. If the circulation operation is stopped, the humidity in the dry cap space 5S may decrease, so the CPU 101 checks whether a predetermined time T2 has been exceeded.

[0072] In S202, CPU 101 determines whether a recording operation command has been received. If CPU 101 determines that a recording operation command has been received, it ends the processing in Fig. 6. On the other hand, if CPU 101 determines that a recording operation command has not been received, it proceeds to S201.

[0073] In S203, the CPU 101 performs a circulation operation to circulate the ink in the print head 3 using the circulation unit 9. In this manner, in this embodiment, the circulation operation is stopped when time T1 has elapsed, and then resumed when time T2 has elapsed. Note that the processing in S203 is the same as in S102, and therefore a description thereof will be omitted.

[0074] In S204, CPU 101 determines whether or not the elapsed time T3 since the start of ink circulation has elapsed. If CPU 101 determines that time T3 has elapsed, it proceeds to S205. On the other hand, if CPU 101 determines that time T3 has not elapsed, it repeats S204. Note that the processing of S204 is the same as S103, and therefore its description will be omitted.

[0075] In S205, the CPU 101 stops the ink circulation operation by the circulation unit 9. The process of S205 is the same as the operation of S104. Through the processes up to this point, the humidity inside the dry cap space 5S returns to the target humidity.

[0076] In S206, the CPU 101 resets the time measured by the timer 105. This process is performed to newly manage the humidity in the dry cap space 5S.

[0077] In S207, the CPU 101 starts counting the unused time using the timer 105. This process is performed in the same manner as in S105. After this, the CPU 101 executes the process of S201 again to continue humidity control in the dry cap space 5S. The CPU 101 continues the moisturizing process during unused time until it confirms in S202 that there is a recording operation command.

[0078] As described above, according to this embodiment, when the recording head 3 is left unused, the recording apparatus 1 covers the ejection surface 30 with the dry cap 50, which does not have an absorber for receiving ink. By covering the ejection surface 30 with the dry cap 50 in this manner, it is possible to prevent the ink in the recording head 3 from drying out due to residual components, such as absorbent solvents, remaining in the absorber 600. Furthermore, while the dry cap 50 is covering the ejection surface 30, the recording apparatus 1 performs a circulation operation in which the circulation unit 9 circulates the ink through the circulation path 90. This circulation operation increases the humidity in the dry cap space 5S, thereby preventing the ink adhering to the ejection surface 30 from drying out. In other words, this embodiment provides a technology for preventing the ink in the recording head 3 from drying out when the recording head 3 is capped.

[0079] In the present embodiment, the humidity in the dry cap space 5S is increased by circulating the ink in the print head 3 using the circulation unit 9, but this is not limiting. For example, when the print head 3 is capped with the dry cap 50, the humidity in the dry cap space 5S may be increased by vibrating the ink in the print head 3. For example, the ink forming the meniscus M may be convected by slightly vibrating the energy generating elements 32, etc. Furthermore, while a configuration in which the circulation unit 9 is provided inside the print head 3 has been described, this is not limiting and the present invention can also be applied to a configuration in which the circulation unit 9 is provided outside the print head 3 (for example, midway through the supply flow path).

[0080] In this embodiment, the recording method of the recording head 3 has been described as a serial scan method, but this is not limited to this. For example, the recording method of the recording head 3 may be a full line method. In the full line method, a long recording head 3 extending in the X direction is used to record an image while continuously transporting the recording medium. Furthermore, even if the recording method of the recording head 3 is a full line method, the recording head 3 may be capped with a dry cap 50 when left unused.

[0081] Furthermore, some of the ink ejected from the ejection ports 31 may remain on the ejection surface 30 of the recording head 3. When the ejection surface 30 is subsequently capped with the dry cap 50, the ink adhering to the ejection surface 30 may be transferred to the portion of the dry cap 50 that contacts the ejection surface 30. Furthermore, some of the ink ejected from the recording head 3 during a recording operation may become mist and float in the recording device 1. This mist of ink may then adhere to the dry cap 50. For example, even if such a small amount of ink adheres to the dry cap 50, dries, and caps the recording head 3, the impact on the ink in the recording head 3 is minimal. In other words, the adhesion of a small amount of ink to the dry cap 50 is not considered to deviate from the spirit of the present invention. The dry cap 50 is a cap that does not eject ink during recording and maintenance operations, preventing waste ink from drying and acting as a water absorbent.

[0082] Second Embodiment Next, the second embodiment will be described with respect to differences from the first embodiment. In the first embodiment, the recording device 1 managed the humidity in the dry cap space 5S based on the elapsed time after the circulation operation was stopped. In this embodiment, the recording device 1 manages the humidity in the dry cap space 5S using a humidity sensor 10.

[0083] FIG. 7 is a schematic diagram illustrating the dry cap 50 of this embodiment. In this embodiment, the recording device 1 includes a humidity sensor 10 that is provided in the dry cap 50 and measures the humidity in the dry cap space 5S. A sensor harness 11 is connected to the humidity sensor 10. The sensor harness 11 is provided to pass through the dry cap 50. The sensor harness 11 transmits an electrical signal from the humidity sensor 10 to the outside. The CPU 101 acquires the humidity change in the dry cap space 5S detected by the humidity sensor 10 via the sensor harness 11. The dry cap 50 and the sensor harness 11 are in close contact with each other. This prevents air in the dry cap space 5S from leaking to the outside through the portion that passes through the dry cap 50.

[0084] The humidity sensor 10 may be, for example, a capacitance-type sensor that measures humidity by sandwiching a polymer film that absorbs and releases moisture between electrodes and measuring the capacitance between the electrodes. Alternatively, the humidity sensor 10 may be a resistance-type sensor that uses a polymer film whose resistance value changes depending on the absorption and release of moisture. Note that the polymer film used is one that is not easily affected by the solvent contained in the ink. Note that a temperature and humidity sensor that can measure the humidity and temperature of the dry cap space 5S may also be used.

[0085] 8 is a flowchart showing an example of an idle capping process executed when the recording head 3 is left unused. The process of FIG. 8 may be started, for example, when the recording device 1 has finished a recording operation. The process of FIG. 8 may also be started, for example, when a maintenance operation for the recording head 3 has finished. The process of FIG. 8 is realized, for example, by the CPU 101 reading a program stored in the ROM 102, which is a computer-readable recording medium, into the RAM 103 and executing the program.

[0086] The processing of S301 and S301 is performed in the same manner as the processing of S101 and S102.

[0087] In S303, the CPU 101 determines whether the humidity in the dry cap space 5S measured by the humidity sensor 10 exceeds a preset target value H1. If the CPU 101 determines that the humidity has exceeded the target value H1, the process proceeds to S304. On the other hand, if the CPU 101 determines that the humidity has not exceeded the target value H1, the process repeats S303. In this embodiment, the recording device 1 determines that the humidity in the dry cap space 5S measured by the humidity sensor 10 has reached the target value H1 as a condition for stopping the circulation operation. In other words, the circulation operation is stopped based on a condition related to a change in humidity in the dry cap space 5S. Note that this target value H1 is the same as that described in S103, and therefore its description will be omitted.

[0088] The process of S304 is performed in the same manner as S104. In this embodiment, the CPU 101 ends the idle capping process.

[0089] Next, reference is made to FIG. 9. FIG. 9 is a flowchart showing an example of a moisturizing process during standing. This process is executed to restore the target humidity level when the humidity in the dry cap space 5S drops while the print head 3 is left standing with the dry cap 50 capped. The process of FIG. 9 is started, for example, when the CPU 101 ends the process of FIG. 8. The process of FIG. 9 is realized, for example, by the CPU 101 reading a program stored in the ROM 102, which is a computer-readable recording medium, into the RAM 103 and executing the program.

[0090] In S401, the CPU 101 measures the humidity in the dry cap space 5S using the humidity sensor 10. Then, the CPU 101 determines whether the humidity in the cap space is below the lower limit H2. If the CPU 101 determines that the humidity is below the lower limit H2, the process proceeds to S403. On the other hand, if the CPU 101 determines that the humidity is not below the lower limit H2, the process proceeds to S403.

[0091] The lower limit value H2 is a value lower than the target value H1. By setting the lower limit value H2 in this way, it is possible to further prevent the ink in the recording head 3 from drying out.

[0092] In S402, CPU 101 determines whether a recording operation command has been received. If CPU 101 determines that a recording operation command has been received, it ends the processing in Fig. 9. On the other hand, if CPU 101 determines that a recording operation command has not been received, it proceeds to S401.

[0093] In S403, the CPU 101 performs a circulation operation to circulate the ink in the print head 3 using the circulation unit 9. That is, in this embodiment, the circulation operation is stopped when the target value H1 is reached, and then resumed when the humidity in the dry cap space 5S measured by the humidity sensor 10 reaches a lower limit value H2. The process of S403 is performed in the same manner as S102 and S203.

[0094] In S404, the CPU 101 measures the humidity in the dry cap space 5S measured by the humidity sensor 10. Then, the CPU 101 determines whether the humidity in the cap space exceeds the target value H1. If the CPU 101 determines that the humidity exceeds the target value H1, the CPU 101 proceeds to S405. On the other hand, if the CPU 101 determines that the humidity does not exceed the target value H1, the CPU 101 repeats the processing of S404. This processing is performed in the same manner as S303.

[0095] In S405, the liquid circulation operation is stopped. This process is performed in the same manner as in S104. After this, the CPU 101 returns to S401 and continues managing the humidity in the dry cap space 5S. The CPU 101 also continues the moisturizing process during idle operation until it confirms in S402 that a printing operation command has been issued.

[0096] As described above, according to this embodiment, when the recording head 3 is left unused, the recording apparatus 1 controls the execution of the circulation operation based on the humidity in the dry cap space 5S measured by the humidity sensor 10. This makes it possible to appropriately manage humidity changes in the dry cap space 5S when the recording head 3 is left unused, thereby preventing the ink from drying out. Furthermore, measuring the humidity with the humidity sensor 10 shortens the operating time of the circulation pump 92, thereby reducing the power consumption of the recording apparatus 1.

[0097] <Third embodiment> Another exemplary configuration of the recording apparatus 1 will be described with reference to FIGS. 11A and 11B. In the first and second embodiments, the communicating path 51 has been described as a tube connected to the dry cap 50, but this is not limiting. The communicating path 51 may be formed inside the dry cap 50, for example, as shown in FIG. 11A. FIG. 11A is a plan view of the dry cap 50, corresponding to a view of the dry cap 50 as viewed from the recording head 3 side. The dry cap 50 has an opening 511 on the dry cap space 5S side. FIG. 11B is a bottom view of the dry cap 50, corresponding to a view of the dry cap 50 as viewed from the recording medium side. The dry cap 50 has an opening 512 on the external space side. In FIGS. 11A and 11B, the communicating path 51 formed inside the dry cap 50 is indicated by a dotted line. The communication passage 51 communicates between the opening 510 on the dry cap space 5S side and the opening 511 on the external space side inside the dry cap 50. The communication passage 51 has a labyrinth shape. Specifically, for example, the communication passage 51 is formed by winding multiple times inside the dry cap 50. As described above, the labyrinth shape of the communication passage 51 can increase the distance from the opening 511 on the dry cap space 5S side to the opening 512 on the external space side. This can prevent a decrease in humidity in the dry cap space 5S. Note that, for example, a tube serving as the communication passage 51 may be further connected to the opening 511 as in the first and second embodiments.

[0098] <Fourth embodiment> However, ink can drip into the cap unexpectedly due to impact, temperature changes, etc. When ink drips into the cap, it is difficult to accurately determine the evaporation rate. If the evaporation rate is inaccurate, proper circulation cannot be achieved, which can lead to poor ejection due to insufficient circulation, or conversely, excessive circulation can lead to a poor user experience.

[0099] Therefore, in this embodiment, a liquid ejection device and a control method that can suppress the occurrence of ejection defects and the increase in viscosity of ink in the ejection ports without impairing the user's usability will be described.

[0100] A fourth embodiment of the present invention will now be described with reference to the drawings.

[0101] 12 is a perspective view showing the appearance of a liquid ejection apparatus (hereinafter also simply referred to as a recording apparatus) 1201 according to this embodiment. The liquid ejection apparatus 1201 is a so-called serial scan printer, and records an image by moving a recording head 1210 in an X direction (scanning direction) perpendicular to a Y direction (transport direction) in which a recording medium 1203 is transported, and ejecting liquid onto the recording medium.

[0102] The following describes an outline of the configuration and operation during printing of the printing device 1201. A printing medium 1203 is conveyed in the Y direction by a conveyance roller driven via a gear by a conveyance motor 204 (see FIG. 13 described later), and after printing, the printing medium 1203 is held by being wound up by a spool 1206.

[0103] Meanwhile, at a predetermined transport position, a carriage motor 205 (see FIG. 13 described later) reciprocates a carriage unit 1202 along a guide shaft 1208 extending in the X direction. A print head 1210 is mounted on the carriage unit 1202, and the print head 1210 moves and scans together with the carriage unit 1202. During this scanning process, liquid is ejected from the ejection openings of the print head 1210 at a timing based on a position signal obtained by an encoder 1207, and a certain bandwidth corresponding to the array range of the ejection openings is recorded on the recording medium 1203. Thereafter, the recording medium 1203 is transported, and the next bandwidth is recorded on the recording medium 1203. In this way, the conveyance of the recording medium 1203 and the scanning of the print head 1210 are alternately repeated to complete the recording.

[0104] When starting printing, an end of the rolled printing medium 1203 is pulled out and fed. The fed printing medium 1203 is sandwiched and transported between a paper feed roller and a pinch roller, and guided to a printing position (scanning area of ​​the print head) on a platen 1204. Normally, when the printing apparatus 1201 is in a resting state, the ejection port surface of the print head 1210, where the ejection ports are provided, is capped by a leaving cap 501 (see FIG. 21 described later) provided in a leaving unit 510 (see FIG. 21 described later). Therefore, prior to printing, the print head 1210 is released from the capping by the leaving cap 501 to make it ready for scanning. Thereafter, once data for one scan has been accumulated in the buffer, the carriage motor 205 moves the carriage unit 1202 to cause the print head 1210 to scan, and printing is performed as described above.

[0105] A carriage belt can be used to transmit the driving force from the carriage motor 205 to the carriage unit 1202. However, instead of a carriage belt, other driving methods may be used, such as a method including a lead screw that is rotationally driven by the carriage motor 205 and extends in the X direction, and an engagement portion that is provided on the carriage unit 1202 and engages with a groove in the lead screw.

[0106] Furthermore, liquid (hereinafter also referred to as ink) supplied to the print head 1210 is supplied from an ink tank 202 (see FIG. 18 described later) mounted in the main body or an external unit via a supply tube 1205 via the carriage unit 1202. Ink may be supplied from the ink tank 202 to the print head 1210 using a pressurizing unit. Alternatively, ink may be supplied from the ink tank 202 by capping the ejection port surface of the print head 1210 where the ejection ports are provided using a recovery cap 211 (see FIG. 16 described later) of a recovery unit described later, and applying negative pressure to the inside of the cap with a suction pump to suck the ink. Furthermore, one print head or multiple print heads capable of ejecting ink of multiple colors may be mounted on the carriage, or a configuration in which one print head capable of ejecting ink of multiple colors is mounted on the carriage may also be used.

[0107] FIG. 13 is a block diagram showing the configuration of a print control system in the printing device 1201. The printing device 1201 is connected to a data supply device such as a host computer (hereinafter referred to as host PC) 306 via an interface 307. Various data and print-related control signals transmitted from the host PC 306 are input to a print control unit 301 of the printing device 1201. The print control unit 301 includes a memory 303 that stores input image data, intermediate multi-level gradation data, and a multi-pass mask, and a CPU 302 (which may be an ASIC) that serves as a control and calculation device. The print control unit 301 includes a data processing unit 305 that processes data input via the interface 307, and an image processing unit 304 that performs predetermined image processing on the input image data to generate an image signal that can be printed by the print head 1210. The print control unit 301 then controls a motor driver and a head driver (described below) according to the processed control signals and image signals.

[0108] The transport motor 204 is a motor that rotates and drives a transport roller for transporting the recording medium 1203. The carriage motor 205 is a motor that reciprocates a carriage that carries the print head 1210. The recovery unit motor 206 is a motor mounted on the recovery unit 210, and switches the unit that is driven by a camshaft, operates the wiper holder 220 and the suction pump 213, and also raises and lowers the recovery cap and the standby cap described below. The circulation pump motor 207 drives mechanisms that contribute to ink circulation, such as a pump 408 (described later) of the print head 1210 (see FIG. 18 described later). A motor driver 308 drives the transport motor 204, a motor driver 309 drives the carriage motor 205, and a motor driver 310 drives the recovery unit motor 206 and the circulation pump motor 207. The head driver 311 is a driver that drives the print head 1210, and when multiple print heads are mounted, multiple head drivers are provided corresponding to the number of print heads.

[0109] FIG. 14 shows an example of a print head 1210 and an ejection orifice group configuration. The print head 1210 is equipped with independent buffer tanks 401C, 401M, 401Y, and 401BK for the four colors of ink: cyan, magenta, yellow, and black. While the buffer tanks are shown visible in FIG. 14 for ease of explanation, the buffer tanks are actually housed inside the print head 1210. Chips 403, each with an array of ejection orifices corresponding to each ink, are arranged on the underside of the print head 1210. The chips 403 each have two arrays of 1,024 ejection orifices 402 spaced 1,200 dpi apart per color, allowing one chip to eject two colors. By arranging two of these, four-color printing is possible.

[0110] The ejection opening arrays 400 corresponding to one color do not need to be arranged on the same straight line, but may be arranged alternately one by one, with a total of four ejection opening arrays 400 each having 512 ejection openings 402 arranged at intervals of 600 dpi. Also, the number of inks that the print head 1210 supports is not limited to four colors, and may be more or less than four.

[0111] The print head 1210 is provided with a discharge port surface 413 in which the discharge ports 402 are provided in the chip 403, and a face surface 414 that includes the discharge port surface 413 and faces the print medium during printing.

[0112] 15 is a plan view showing the chip 403. Temperature sensors S6, S7, S8, and S9 made of diodes for detecting the temperature of the chip 403 are formed along the sides of the chip 403 on the sides where both ends of the ejection port array 400 are located. Temperature sensors S6 to S9 are located approximately 0.2 mm away from the outermost ejection port of the ejection port array 400 in the sub-scanning direction (Y direction), and are located at intermediate positions between the two ejection port arrays in the main scanning direction (X direction). Temperature sensors S1, S2, S3, S4, and S5 made of diodes for detecting the temperature at the center of the ejection port array 400 are formed in the center of the arrangement direction of the ejection ports 402, and are located at intermediate positions sandwiched between the two ejection port arrays 400.

[0113] The heaters 1900 and 2000 are formed along the outer periphery of the chip 403, positioned 1.2 mm outward from the outermost ejection port row in the main scanning direction (X direction) and 0.2 mm outward from the temperature sensors S6, S7, S8, and S9 in the sub-scanning direction (Y direction). The overall size of the chip 403 is 9.55 mm x 39.0 mm in the X direction (hereinafter also referred to as horizontal) x Y direction (hereinafter also referred to as vertical). The heaters 1900 and 2000 are also provided on the chip 403. The heaters 1900 and 2000 heat the chip 403 heated by the heater element 3000. This prevents changes in the ink viscosity within the print head 1210 and controls the ink temperature to maintain a constant viscosity regardless of the ambient temperature. The print head 1210 is provided with a driver (driving unit) (not shown), which is connected to each of the heating elements 3000 and is configured to be able to control the drive current of the heating elements 3000 to be ON or OFF.

[0114] FIG. 16 is a perspective view showing the recovery unit 210. The recovery unit 210 includes a recovery cap 211, wipers 221 and 222, a wiper holder 220, a guide 223, and a suction pump 213. The recovery cap 211 is supported by a lifting mechanism (not shown) so that it can move up and down, and is configured to be movable between a raised position and a lowered position. In the raised position, the recovery cap 211 abuts against the print head 1210 and covers (caps) the ejection port surface 413 on which the ejection ports 402 of the print head 1210 are provided. By covering the ejection port surface 413 of the print head 1210, the recovery cap 211 can drive the suction pump 213 to suck ink from the print head 1210 and recover the ejection state.

[0115] An absorber 214 capable of absorbing and holding a predetermined amount of ink is provided inside the recovery cap 211. During non-printing operations, the ejection port surface 413 is covered with a leaving cap, which will be described later, to prevent the ink from drying out at the ejection ports 402, and therefore the recovery cap is not used. During printing operations, the recovery cap 211 is located in a lowered position to avoid interference with the print head 1210, which moves together with the carriage 1202. With the recovery cap 211 located in the lowered position, when the print head 1210 moves to a position where the ejection port surface 413 faces the recovery cap 211, preliminary ejection can be performed, in which ink is ejected from the ejection ports 402 toward the recovery cap 211.

[0116] The wipers 221 and 222 are made of an elastic material such as rubber. In this embodiment, two wipers 221 are provided to wipe the ejection port surfaces 413 of the two chips 403 (see FIG. 14), and a wiper 222 is provided to wipe the face surface 414 including the ejection port surfaces 413 of the two chips 403 in the print head 1210.

[0117] The wipers 221 and 222 are fixed to a wiper holder 220. The wiper holder 220 is configured to be movable in the Y direction (the arrangement direction of the ejection ports 402 in the print head) along a guide 223, as indicated by an arrow W. When the print head 1210 is positioned at the standby position, the wiper holder 223 moves in the direction of the arrow W (one direction), thereby performing a wiping operation in which the wipers 221 and 222 wipe the ejection port surface 413 while coming into contact with the ejection port surface 413. When the wiping operation is completed, the carriage 1202 is moved and retracted from the area where the wiping operation is performed, and then the wiper holder 220 is moved to return the wipers 221 and 222 to their original positions (the positions before the wiping operation).

[0118] In this embodiment, a tube pump is used as the suction pump 213. The tube pump has a holding portion 5000 formed with a curved surface along which the tube 212 (at least a portion of it) is held, a roller 5100 capable of pressing the held tube 212, and a roller support portion 5200 rotatably supporting the roller. The tube pump rotates the roller while squeezing the tube 212 by rotating the roller support portion in a predetermined direction. This generates negative pressure inside the recovery cap 211, and sucks ink from the print head 1210. The sucked ink is discharged into the waste ink absorber via the tube 212.

[0119] The suction operation is also performed when a purge operation is performed on the recovery cap 211 by the print head 1210, and the ink received in the recovery cap 211 by the purge operation is discharged. That is, when the purge operation is performed and the ink held in the recovery cap 211 reaches a predetermined amount, the suction pump 213 is driven to discharge the ink held in the recovery cap 211 into the waste ink absorber via the tube 212. However, it is difficult to completely discharge the ink held in the recovery cap 211, and therefore a certain amount of ink always remains in the recovery cap 211.

[0120] The suction pump 213 is driven when the recovery cap 211 covers the ejection port surface 413 of the print head 1210, creating a substantially sealed space inside, and performs a suction operation to suck ink from the print head 1210 by generating negative pressure inside. This suction operation is performed when filling the print head 1210 with ink from the ink tank 202 (initial filling) and when sucking and removing dust, solidified matter, air bubbles, etc. from inside the ejection ports (suction recovery). The recovery cap 211 is connected to a waste ink absorber (not shown) via a flexible tube 212.

[0121] In this embodiment, the wipers 221 and 222 may be made of an elastic material such as rubber, or may be made of a porous material that absorbs ink. The recovery operation using an elastic material will be described below with reference to FIG.

[0122] FIG. 17 shows the print head 1210 and the wipers 221 and 222 of the recovery unit 210 during wiping. The wipers 221 and 222 are moved in the direction of arrow W (wiping direction) to move the print head 1210 and the rubber elastic bodies (wipers 221 and 222) relative to each other, thereby wiping the ejection port surface 413 and the face surface 414. At this time, the rubber elastic bodies perform a cleaning operation by moving downstream in the wiping direction without absorbing ink adhering to the ejection port surface 413. Therefore, if a large amount of ink is adhering to the ejection port surface 413, the adhering ink may enter the print head 1210 through the ejection ports 402, causing color mixing. To eliminate this color mixing, after wiping (wiping operation) by the wipers 221 and 222, a purging operation is performed on the recovery cap 211 to discharge the mixed color ink that has entered through the ejection ports 402.

[0123] Fig. 18 is a schematic diagram showing the configuration of the print head 1210 and buffer tank 401. Note that Fig. 18 shows a schematic diagram of a flow path for one color, but as described above, buffer tanks and flow paths for four colors, cyan, magenta, yellow, and black, are configured in one print head 1210.

[0124] The supply tube 1205 is connected to a joint 404 of the print head 1210 through the inside of the carriage unit 1202, and connects the ink tank 202 with the buffer tank 401. The ink supplied to the print head 1210 passes through the filter 405 and a flow path in the buffer tank 401 to reach a first pressure adjustment chamber 406. The first pressure adjustment chamber 406 is connected to a second pressure adjustment chamber 407. The first pressure adjustment chamber 406 is also connected to the second pressure adjustment chamber 407 via a separate flow path via a pump 408.

[0125] A valve 411 that opens when a predetermined negative pressure is reached is provided at the inlet of first pressure adjustment chamber 406, and a valve 412 that opens when a predetermined negative pressure is reached is provided at the inlet of second pressure adjustment chamber 407. The inlet of first pressure adjustment chamber 406 is provided in a flow path between filter 405, and the inlet of second pressure adjustment chamber 407 is provided in a flow path between first pressure adjustment chamber 406. In addition, the negative pressure at which valve 412 at the inlet of second pressure adjustment chamber 407 opens is configured to be higher than the negative pressure at which valve 411 of first pressure adjustment chamber 406 opens.

[0126] Ink is supplied to the chip 403 from the first pressure adjustment chamber 406 via the joint 404 and a common supply flow path 409 formed in the print head 1210 to supply flow paths (described later) of one or more ejection port arrays arranged in the chip 403. Then, the ink passing through the ejection ports 402 is returned to the second pressure adjustment chamber 407 from a recovery flow path (described later) in the chip 403 through a common recovery flow path 410 formed in the print head 1210.

[0127] FIG. 19 is a cross-sectional view showing the discharge port 402, common channel 431, and recovery channel 432 formed in chip 403, and FIG. 20 is a plan view showing the discharge port 402, inlet 421, and outlet 422.

[0128] The chip 403 is formed by laminating an orifice plate 420, a substrate 430, and a cover plate 440. The orifice plate 420, on whose surface a plurality of ejection ports 402 are formed, is provided. The substrate 430 is provided with ejection energy generating elements 423 that generate ejection energy for ejecting ink. The chip 403 is provided with pressure chambers 80 corresponding to the ejection energy generating elements 423. An electrothermal conversion element (heater), a piezoelectric element, or the like can be used as the ejection energy generating element 423. When a heater is used, the heat generated by the heater causes the ink in the pressure chambers 80 to bubble, and the resulting bubble generating energy is used to eject ink from the ejection ports 402.

[0129] When ink is supplied into the ejection port 402, the ink is maintained at a negative pressure such that a meniscus is formed at the ejection port 402. Two flow paths, an inlet 421 and an outlet 422, are formed on both sides of the ejection port 402, and in this embodiment, the inlet 421 and the outlet 422 are arranged so that one inlet 421 and one outlet 422 correspond to each of two ejection ports 402, as shown in Fig. 20. The number of inlet 421 and outlet 422 may be one per ejection port 402, or may be more than two per ejection port 402.

[0130] The inlet 421 is connected to a supply flow path 431 formed along the ejection port array 400, and the outlet 422 is connected to a recovery flow path 432 formed along the ejection port array 400. The supply flow path 431 and the recovery flow path 432 are covered with a cover plate 440, and are connected to a common supply flow path 409 and a common recovery flow path 410 of the print head 1210 via openings 441 on the cover plate. One or more openings 441 are provided for each supply flow path 431 and recovery flow path 432. The number of openings 441 may be the same for the supply flow path 431 and the recovery flow path 432, or may be different.

[0131] The method of supplying ink to the print head 1210 and the buffer tank, and the method of circulating ink within the ejection ports in this embodiment will be described below.

[0132] Ink is pressurized from the ink tank 202 (see FIG. 18 ) and reaches the inside of the print head 1210 via the supply tube 1205, and after passing through the filter 405, is able to circulate within the print head 1210. When the print head 1210 is filled with ink at an appropriate negative pressure so that a meniscus is maintained within the ejection port 402, the valve 411 at the inlet of the first pressure adjustment chamber 406 is closed, and ink does not flow into the first pressure adjustment chamber 406. However, when a strong negative pressure is applied to the ejection port 402 by the suction action of the recovery cap 211 of the recovery unit 210, or when ink is ejected from the ejection port 402, and the negative pressure in the first pressure adjustment chamber 406 increases, the valve 411 at the inlet opens, and ink flows into the first pressure adjustment chamber 406.

[0133] 18 , the first pressure adjustment chamber 406 and the second pressure adjustment chamber 407 are connected to a pump 408. When the pump 408 is driven, ink is transferred from the second pressure adjustment chamber 407 to the first pressure adjustment chamber 406 via the pump 408. This increases the negative pressure in the second pressure adjustment chamber 407, and opens a valve 412 at the inlet of the second pressure adjustment chamber 407, causing ink to flow back from the first pressure adjustment chamber 406 to the second pressure adjustment chamber 407. At this time, a pressure difference occurs between the first pressure adjustment chamber 406 and the second pressure adjustment chamber 407. Therefore, ink passes through the flow paths from the first pressure adjustment chamber 406 to the common supply flow path 409, the cover plate opening 441, the supply flow paths 431 of each ejection port array, and the inlet 421 in this order, and some of the ink flows into the ejection ports 402 via the pressure chamber 80. Furthermore, ink in the pressure chamber 80 that is not ejected from the ejection port 402 passes through the flow path in the order of the outlet 422 → recovery flow path 432 → cover plate opening 441 → common recovery flow path 410, and returns to the second pressure adjustment chamber 407 (see FIG. 19). That is, the flow of ink in the chip 403 is in the direction of the arrow shown in FIG.

[0134] The negative pressure and ink flow rate inside the ejection port 402 are adjusted by the pump flow rate, the pressure loss in the flow path between the first and second pressure chambers, and the opening and closing force of the inlet valve so that they fall within a range that allows a meniscus to be maintained at the ejection port 402.

[0135] FIG. 21 is a perspective view showing the standing unit 510. The standing unit 510 includes a standing cap 501 and an absorber 502. The standing unit 510 is supported by an elevator mechanism (not shown) so that it can move up and down, and is configured to be movable between an elevated position and a lowered position. In the elevated position, the standing cap 501 abuts against the print head 1210 and covers (caps) the ejection port surface 413 of the print head 1210. During printing, the standing cap 501 is positioned in the lowered position to avoid interference with the print head 1210, which moves together with the carriage 1202. Similar to the recovery cap 211, an absorber 502 capable of absorbing and holding a predetermined amount of ink is provided within the standing cap 501.

[0136] The inner dimensions of one storage cap 501 are 12 mm wide x 45 mm long x 3 mm deep, which is large enough to cover the chip 403 by capping. The absorber 502 has dimensions of 11 mm wide x 44 mm long x 1 mm high, which means that the absorber 502 does not come into contact with the chip 403 even when capped.

[0137] The standing cap 501 is not connected to a pump like the one in the recovery unit 210, and even if the discharge port surface 413 is capped with the standing cap 501, no suction or purging operation is performed. Therefore, basically, no ink or dried ink exists in the standing cap 501. When not performing printing, the standing cap 501 covers the discharge port surface 413, thereby preventing the ink in the discharge ports 402 from losing moisture and becoming viscous.

[0138] In this way, the standby cap 501 is used when the print head 1210 is on standby and not in printing operation, with the ejection port surface 413 of the print head 1210 capped. The recovery cap 211 is used when the suction pump 213 is driven to perform suction for recovery processing or when a purge operation is performed.

[0139] 22 is a diagram showing the positional relationship between the recovery unit 210 and the standing unit 510 in the recording apparatus 1201 of this embodiment. When viewed from the front, the recovery unit 210 and the standing unit 510 are arranged with the platen 1204 in between, with the standing unit 510 on the left and the recovery unit 210 on the right. Note that this positional relationship is not particularly limited, and for example, the standing unit 510 may be arranged on the right and the recovery unit 210 on the left. Alternatively, the standing unit 510 and the recovery unit 210 may be arranged adjacent to each other on either the left or right side.

[0140] As described above, ink normally does not adhere to the inside of the standing cap 501. However, for example, if the print head 1210 is subjected to an impact while capped with the standing cap 501, or if the air inside the print head 1210 expands due to a temperature change and breaks the meniscus at the ejection port 402, ink may drip into the standing cap 501. The ink that drips into the standing cap 501 dries while the cap is open, becoming dried ink. If the standing cap 501 is capped while dried ink is present, the dried ink inside the standing cap 501 absorbs moisture, reducing the humidity in the space inside the standing cap 501. As a result, moisture is removed from the ink inside the ejection port, which may cause ejection problems.

[0141] 23 is a graph showing the change in relative humidity inside the standing cap 501 when the ejection port surface 413 of the print head 1210 is capped with the standing cap 501 after a printing operation in an environment of 30°C and 10% RH. The dashed-dotted line shows the change in humidity when there is no dried ink inside the standing cap 501, and the dotted line shows the change in humidity when there is dried ink inside the standing cap 501. When there is no ink inside the standing cap 501, moisture evaporates and diffuses from the ink inside the ejection ports into the space inside the standing cap after capping, causing the humidity inside the cap to rise rapidly and equilibrate at a value corresponding to the water vapor pressure of the ink inside the ejection ports.

[0142] In addition, when the effective volume (cap internal volume minus the absorber volume) inside the cap (inside the cap means) during capping of the leaving cap 501 is increased from 30°C and 10% RH to 30°C and 100% RH, for example, the amount of moisture released into the space inside the cap is approximately 0.03 mg. If the moisture amount is approximately 0.03 mg, even if moisture evaporates from the ink inside the ejection ports, the effect of increased viscosity of the ink is small, and in fact, in this embodiment, it was confirmed that the ejection performance was good even 60 hours after capping.

[0143] On the other hand, if dried ink is present in the storage cap 501, moisture that evaporates and diffuses from the ink in the ejection ports into the space inside the cap after capping is absorbed by the dried ink, resulting in a slow rise in the humidity inside the cap. Furthermore, as moisture further evaporates and diffuses from the ink inside the ejection ports, the ink at the ejection ports 402 becomes more viscous, and the equilibrium humidity inside the cap also decreases. In this embodiment, it was confirmed that if dried ink is present in the cap, ejection defects occur four hours after capping.

[0144] In this way, if dried ink is present in the standing cap 501, the ink may thicken at the ejection ports even when the cap is closed, resulting in ejection defects. Therefore, in this embodiment, the occurrence of ejection defects is suppressed by controlling the humidification inside the standing cap. The following describes the control of humidification inside the standing cap in this embodiment.

[0145] 24(a) to 24(c) are flowcharts showing the humidification control in the standing cap. FIG. 24(a) is a flowchart showing the overall humidification control in the standing cap, FIG. 24(b) is the process at S1340 in FIG. 24(a), and FIG. 24(c) is the process at S1350 in FIG. 24(a). The series of processes shown in FIGS. 24(a) to 24(c) are performed by the CPU 302 of the recording device 1201 by expanding and executing program code stored in the memory 303. Alternatively, some or all of the functions of the steps in FIGS. 24(a) to 24(c) may be realized by hardware such as an ASIC or electronic circuit. Note that the symbol "S" in the description of each process indicates a step in the flowchart. Below, the humidification control in the standing cap according to this embodiment will be described using the flowchart in FIG. 24(a).

[0146] The control of humidifying the inside of the standing cap is started when recording is completed and the recording head 1210 comes to a position facing the standing cap 501. When the control of humidifying the inside of the standing cap is started, the CPU 302 controls the lifting mechanism of the standing cap 501 in S1310 to put the standing cap 501 in a cap-closed state. The CPU 302 starts a timer Tm in S1320 and sets the number of cycles N to 0 in S1330. This timer Tm is provided in the recording device 1201 and counts the duration T of the cap-closed state of the standing cap 501 (referred to as the capping time).

[0147] The CPU 302 can acquire the capping time at any timing. Next, in S1340, the CPU 302 controls the pump 408 in the print head 1210 to execute a "humidification circulation mode" in which circulation is performed intermittently every first circulation interval T1 (one hour in this embodiment) until the upper limit number (upper limit value) Nth=12 times is reached. After the humidification circulation mode is completed, the CPU 302 executes a "maintenance circulation mode" in S1350 in which circulation is performed intermittently every second circulation interval T2 (24 hours in this embodiment). In this embodiment, the circulation time for one cycle is 10 seconds in either mode. The first circulation interval T1 is set to be within one hour.

[0148] The purpose of implementing the humidification circulation mode is to quickly humidify the inside of the standing cap after capping, and to maintain a high humidity even if dried ink is attached to the inside of the standing cap 501. The purpose of implementing the retention circulation mode is to periodically refresh the thickened ink inside the ejection ports in the capping state with the standing cap 501 moistened in the humidification circulation mode.

[0149] The humidified circulation mode will be described using the flowchart in Figure 24(b). When processing in the humidified circulation mode is started, the CPU 302 determines in S1341 whether the recording device 1201 has been powered off. If the determination result is true, the humidified circulation mode ends. If the determination result is false, the process proceeds to S1342. In S1342, the CPU 302 determines whether a recording command is present. If the determination result is true, the humidified circulation mode ends. If the determination result is false, the process proceeds to S1343.

[0150] In S1343, the CPU 302 determines whether the elapsed time T measured by the timer Tm exceeds the first circulation interval T1 × (number of circulations N+1). In this embodiment, the first circulation interval T1 = 1 hour. If the determination result is false, the process returns to S1341. If the determination result is true, the process proceeds to S1344. In S1344, the CPU 302 drives the pump 408 (see FIG. 18) in the print head 1210 to circulate the ink in the ejection orifices. In this embodiment, the pump is driven for 10 seconds (circulation time). This circulation fills the ink in the ejection orifices, including the ink in the ejection orifices, from the supply flow path 431 and the recovery flow path 432, with fresh ink. As a result, ejection stability (the ability to stably eject ink from the ejection orifices) is restored, and the humidifying ability of the ink near the ejection orifices is also restored, allowing the space inside the leaving cap 501 to be maintained at a high humidity.

[0151] In S1345, CPU 302 adds 1 to the circulation count N. In S1346, CPU 302 determines whether the circulation count N has exceeded the upper limit Nth of the circulation count in the humidified circulation mode. In this embodiment, the upper limit Nth is 12, so the humidified circulation mode essentially continues for 12 hours from capping. If the determination result is false, CPU 302 returns to S1341 and continues the humidified circulation mode; if the determination result is true, CPU 302 ends the humidified circulation mode and transitions to the maintenance circulation mode in S1350.

[0152] The retain cycle mode will be described using the flowchart in Figure 24(c). When processing in the retain cycle mode is started, the CPU 302 resets the elapsed time T of the timer Tm (T = 0) in S1351. The CPU 302 restarts the timer Tm in S1352. The CPU 302 resets the cycle count N (N = 0) in S1353. The CPU 302 determines whether the recording device 1201 has been powered off in S1354. If the determination result is true, the retain cycle mode ends. If the determination result is false, the process proceeds to S1355. The CPU 302 determines whether a recording command is present in S1355. If the determination result is true, the retain cycle mode ends. If the determination result is false, the process proceeds to S1356.

[0153] In S1356, the CPU 302 determines whether the elapsed time T on the timer Tm has exceeded the second circulation interval T2 × (number of circulations N+1). In this embodiment, the second circulation interval T2 = 24 hours. Because the space inside the leaving cap 501 and the ink adhering inside the leaving cap 501 are moistened by going through the humidification circulation mode in S1340, the second circulation interval T2 can be set to a time longer than the first circulation interval T1. If the determination result in S1356 is false, the process returns to S1354. If the determination result is true, the process proceeds to S1357.

[0154] In S1357, the CPU 302 drives the pump 408 (see FIG. 18) in the print head 1210 to circulate the ink in the print head 1210. In this embodiment, the pump drive time (circulation time) is 10 seconds, the same as in the humidified circulation mode, but in the retention circulation mode, the progress of ink thickening at the ejection ports is suppressed by the humidity inside the leaving cap 501. Therefore, for example, the circulation time may be set shorter than in the humidified circulation mode, so that the ink in the ejection ports is replaced with fresh ink.

[0155] In S1358, the CPU 302 adds 1 to the circulation count N. In S1359, the CPU 302 determines whether the circulation count N has exceeded the upper limit Nmax for the retention circulation mode. In this embodiment, Nmax = 60 times, so the retention circulation mode will essentially continue for 60 days. The upper limit Nmax is set to prevent the retention circulation mode from continuing indefinitely. If the determination result in S1359 is false, the process returns to S1353 to continue the retention circulation mode, and if the determination result is true, the retention circulation mode is terminated. This completes all the steps of the humidification control inside the standing cap shown in Figure 24(a).

[0156] Figure 25 is a graph showing the change in relative humidity inside the standing cap 501 when the humidified circulation mode of this embodiment is performed in an environment of 30°C and 10% RH. The solid line shows the change in humidity when the humidified circulation mode is performed with a predetermined amount of dried ink (similar to the conditions indicated by the dashed line in Figure 23) attached inside the standing cap 501. For comparison, the dashed and dotted lines in Figure 25 represent the same data as those shown in Figure 23.

[0157] By implementing the humidified circulation mode, the inside of the standing cap is repeatedly humidified by intermittent circulation at short intervals for a predetermined time after capping with the standing cap 501. Therefore, even if dried ink adheres to the inside of the cap, the inside of the cap space can be maintained at a relatively high humidity. Therefore, the dried ink adhered to the inside of the cap is placed in a high-humidity environment during the implementation period of the humidified circulation mode (first circulation interval T1 × upper limit number Nth), and gradually absorbs moisture and becomes moist. Therefore, it is possible to maintain a high humidity inside the standing cap even after the humidified circulation mode has ended.

[0158] Furthermore, because the humidity inside the standing cap 501 only rises to a value corresponding to the water vapor pressure of the ink inside the ejection ports, it is possible to prevent the attached dried ink from becoming more (excessively) wet than its original state. Also, if the ink attached inside the standing cap 501 is only slightly dried or if the amount of ink attached is small, the attached ink is moistened according to the state, and the standing cap 501 can be maintained at an appropriate humidity without becoming excessively dry. On the other hand, if there is no dried ink inside the cap, the space inside the cap can be efficiently humidified without moisture being lost to the dried ink.

[0159] In this way, after capping with the storage cap, circulation is performed at relatively short intervals (1 hour) until a predetermined time (24 hours) has passed, and then at relatively long intervals after the predetermined time has passed. This allows the inside of the cap to be kept appropriately moist regardless of whether or not ink drips into the cap. As a result, ejection defects can be suppressed and thickening of the ink at the ejection ports can be suppressed without impairing the user's experience.

[0160] Fifth Embodiment A fifth embodiment of the present invention will be described below with reference to the drawings. The basic configuration of this embodiment is the same as that of the fourth embodiment, so only the characteristic configuration will be described below. In this embodiment, after capping with the leaving cap 501, the humidification circulation mode is performed but the maintenance circulation mode is not performed, and upon receiving a signal to start printing, recovery circulation is performed. Here, recovery circulation is a circulation operation performed on the print head before the start of printing. In this embodiment, the circulation operation time in recovery circulation is changed depending on the implementation status of the humidification circulation mode.

[0161] FIG. 26(a) is a flowchart showing the humidification control in the standing cap in this embodiment, and FIG. 26(b) is a flowchart showing the recovery circulation process. The series of processes shown in FIGS. 26(a) to 26(b) are performed by the CPU 302 of the recording device 1201 by expanding and executing program code stored in the memory 303. Alternatively, some or all of the functions of the steps in FIGS. 26(a) to 26(b) may be realized by hardware such as an ASIC or electronic circuit. Note that the symbol "S" in the description of each process indicates a step in the flowchart. Below, the humidification control in the standing cap in this embodiment will be described using the flowchart in FIG. 26(a).

[0162] The control of humidifying the inside of the standing cap is started when recording is completed and the recording head 1210 comes to a position facing the standing cap 501. When the control of humidifying the inside of the standing cap is started, the CPU 302 controls the lifting mechanism of the standing cap 501 in S1510 to put the standing cap 501 in the cap closed state. The CPU 302 starts the timer Tm in S1520 and sets the number of circulations N to 0 in S1530.

[0163] Thereafter, in S1540, CPU 302 determines whether the humidified circulation mode is permitted, and if permitted, proceeds to S1550 to enter the humidified circulation mode. In this embodiment, the user can arbitrarily select whether to implement the humidified circulation mode. Immediately after starting use of the device or in a situation where it is known that no ejection defects have occurred, it is effective to not implement the humidified circulation mode (not permitted), but to implement the humidified circulation mode (permitted) in a situation where it is desired to more reliably suppress ejection defects or in a situation where an ejection defect has already occurred. In this embodiment, the user can selectively set whether to implement such a humidified circulation mode. Note that the humidified circulation mode (S1550) is the same as in embodiment 1, and therefore description thereof will be omitted.

[0164] The recovery circulation process in this embodiment will be described below with reference to the flowchart in Fig. 26(b). The humidification control in the leaving cap in Fig. 26(a) and the recovery circulation process in Fig. 26(b) are performed in parallel.

[0165] Upon receiving a recording start signal, the CPU 302 acquires the elapsed time Ta and circulation count N on the timer Tm in S1570, and sets a recovery circulation time by referring to a recovery circulation time selection table described below. In S1580, the CPU 302 performs recovery circulation based on the recovery circulation time set in S1570. Thereafter, in S1590, the CPU 302 starts a recording operation and ends the process.

[0166] FIG. 27 shows a recovery circulation time selection table referenced in the recovery circulation time setting process in this embodiment. The recovery circulation time selection table is referenced in S1570 of FIG. 26(b). For example, if the power is turned off when the circulation count N in the humidified circulation mode reaches N=4 and a recording signal is input at Ta=48 hours, the CPU 302 sets the recovery circulation time to 60 seconds, assuming an upper limit of Nth=12. Note that the timer Tm continues to measure the elapsed time even when the power is turned off. Furthermore, if the circulation count N in the humidified circulation mode reaches the upper limit of Nth=12 and a recording signal is input at Ta=48 hours, the recovery circulation time is set to 0 seconds (none).

[0167] In this way, if the humidified circulation mode is interrupted midway, a long time is set as recovery circulation because there is a possibility that the humidity inside the leaving cap 501 is not sufficient, and if the humidified circulation mode is carried out to the end, a short time is set as recovery circulation. Note that, since intermittent circulation is performed for a short time (first circulation interval T1) during the humidified circulation mode, if a recording signal is input during the humidified circulation mode, the recovery circulation time is set to 0 seconds (none).

[0168] In this embodiment, the humidified circulation mode is performed immediately after capping with the leaving cap 501, and when a recording signal is input, a recovery operation is performed before the start of recording for a circulation time according to the implementation status of the humidified circulation mode.

[0169] Sixth Embodiment A sixth embodiment of the present invention will be described below with reference to the drawings. The basic configuration of this embodiment is the same as that of the fourth embodiment, so only the distinctive configuration will be described below. In this embodiment, control is described for detecting the amount of ink attached inside the leaving cap 501 and setting the upper limit number Nth of times the humidified circulation mode can be performed in accordance with the detected amount of attached ink. In this embodiment, the recording device 1201 is equipped with a detection means (not shown) that detects the amount of ink attached inside the leaving cap 501. The detection means photographs the absorber 502 (see FIG. 21) inside the leaving cap using an imaging element (not shown), and derives the ink attachment rate from the ink-adhered area of ​​the absorber 502.

[0170] FIG. 28 is a flowchart showing the humidification control in the standing cap in this embodiment, FIG. 29(a) is a diagram showing an example of detection of the ink adhesion rate S to the absorber 502, and FIG. 29(b) is a diagram showing a table for setting the upper limit number of times Nth. The series of processes shown in FIG. 28 are performed by the CPU 302 of the recording device 1201 expanding and executing program code stored in the memory 303. Alternatively, some or all of the functions of the steps in FIG. 28 may be realized by hardware such as an ASIC or electronic circuit. Note that the symbol "S" in the explanation of each process indicates a step in the flowchart. Below, the humidification control in the standing cap in this embodiment will be explained using the flowchart in FIG. 28.

[0171] When humidification control inside the leaving cap 501 is started, the CPU 302, in S1710, uses an image sensor (not shown) to capture an image of the absorber 502 inside the leaving cap 501, and derives the ink adhesion rate S from the ink-adhered area of ​​the absorber 502. As shown in FIG. 29(a), the ink adhesion rate S is derived from the proportion of the absorber 502 to which ink adheres. Note that in this embodiment, the amount of ink adhesion is detected before the cap is closed, but it is also possible to perform detection at a different time and obtain the latest detection result. Furthermore, the means for detecting the amount of ink adhesion is not limited to an image sensor, and it is also possible to use, for example, a method in which an electrode is placed inside the cap to detect the amount of adhesion or whether or not adhesion is present, or a method in which a humidity sensor is placed inside the cap to estimate the amount of ink adhesion from the humidity change during capping.

[0172] In S1720, the CPU 302 controls the lifting mechanism of the leaving cap 501 to place the leaving cap 501 in the cap closed state. Thereafter, in S1730, the CPU 302 starts the timer Tm. In S1740, the CPU 302 resets the circulation count N (N=0).

[0173] In S1750, the CPU 302 references the table in FIG. 29(b) and sets the upper limit number Nth for the humidified circulation mode based on the ink adhesion rate S acquired in S1710. For example, if the ink adhesion rate S is 10%, the upper limit number Nth is set to 12 times, and if the ink adhesion rate S is 60%, the upper limit number Nth is set to 36 times. This is because the more dried ink there is in the cap, the longer it takes to moisten it, so the operation time of the humidified circulation mode is extended to maintain high humidity inside the cap for a longer period of time. Note that if the ink adhesion rate S exceeds 75%, the upper limit number Nth is set to 48 times, and a notification is issued to the user, such as to encourage cleaning the standing cap 501.

[0174] Here, the upper limit number of times Nth is set based on the ink adhesion rate S, but the first circulation interval T1 is not set specifically based on the ink adhesion rate S. This is because the first circulation interval T1 is a variable that has a short-term effect, and the effect of the ink adhesion rate S on drying is less likely to appear. In contrast, the upper limit number of times Nth is a variable that has a long-term effect, and the effect of the ink adhesion rate S on drying is more likely to appear. For this reason, the upper limit number of times Nth is selected taking the ink adhesion rate S into consideration.

[0175] At S1760, the CPU 302 shifts to the humidified circulation mode. Then, the maintenance circulation mode is executed based on the upper limit number Nth set at S1750. Thereafter, at S1770, the CPU 302 shifts to the maintenance circulation mode. The flows of the humidified circulation mode and the maintenance circulation mode are the same as those described in the fourth embodiment, and therefore description thereof will be omitted. This concludes the humidification control process in the standing cap of this embodiment.

[0176] Figure 30 is a graph showing the change in the evaporation rate of moisture from the dried ink adhering to the storage cap 501 when the storage cap 501 with dried ink adhering thereto is placed in a high humidity environment of 30°C and 90% RH. The solid line shows the change in the evaporation rate of the adhering ink when the initial state is a dried state with an ink adhesion rate S of approximately 25%. Under these conditions, the dried ink initially evaporated at 60%, but after 12 hours it moistened to approximately 6% evaporation, with almost no change thereafter.

[0177] The dashed line shows the transition of the evaporation rate of the adhered ink when the ink adhesion rate S is set to 100% and the initial state is when ink is dripped up to the holding limit of the absorber 502 and then dried. The wetting speed is slower than when the amount of dried ink is small, and under these conditions, it took about 48 hours for evaporation to reach about 6%.

[0178] As described above, the time required for wetting varies depending on the amount of dried ink adhering to the inside of the storage cap 501, but according to this embodiment, it is possible to ensure an appropriate high humidity retention time according to the amount of ink adhering.

[0179] Seventh Embodiment A seventh embodiment of the present invention will be described below with reference to the drawings. The basic configuration of this embodiment is the same as that of the fourth embodiment, so only the characteristic configuration will be described below. In this embodiment, the recording apparatus 1201 is equipped with an ink adhesion amount detection unit inside the leaving cap 501. In this embodiment, the amount of water evaporation Vco from the ink adhering to the cap is calculated according to the open time of the leaving cap 501, and Vco is added to the water lost from the ink in the circulation path when the humidified circulation mode is performed.

[0180] FIG. 31 is a flowchart showing the humidification control in the standing cap in this embodiment, and FIGS. 32(a) and 32(b) are diagrams showing tables referenced in the flowchart in FIG. 31. The series of processes shown in FIG. 31 are performed by the CPU 302 of the recording device 1201 expanding and executing program code stored in the memory 303. Alternatively, some or all of the functions of the steps in FIG. 31 may be implemented by hardware such as an ASIC or electronic circuit. Note that the symbol "S" in the description of each process indicates the step in the flowchart. Below, the humidification control in the standing cap in this embodiment will be described using the flowchart in FIG. 31. The processes from S2010 to S2011 are similar to the processes from S1710 to S1720 in FIG. 28 of the sixth embodiment. The processes from S2015 to S2016 and S2018 are similar to the processes from S1730 to S1740 and S1760 in FIG. 28. Therefore, the description of the processes from S2010 to S2011, S2015 to S2016, and S2018 will be omitted.

[0181] In S2012, the CPU 302 determines whether or not there is ink adhering inside the leaving cap 501. If there is no ink adhering and the determination result is false, the process proceeds to S2015. If there is ink adhering inside the leaving cap 501 and the determination result is true, the process proceeds to S2013. In S2013, the CPU 302 acquires the elapsed time Tco from the previous opening of the leaving cap 501 to its closing (S2011). In S2014, the CPU 302 derives the amount of evaporation Vcap of water from the ink adhering inside the leaving cap 501 from the amount of ink adhering inside the leaving cap 501 acquired in S2010 and the elapsed time Tco acquired in S2013.

[0182] In S2017, the CPU 302 sets the first circulation interval T1 and the upper limit number of cycles Nth in the humidified circulation mode. The first circulation interval T1 is set based on the water evaporation rate Vp (acquired result) acquired in S2019 (described later) and the table in Figure 32(a). When no water evaporation has occurred after the device has been used, 60 minutes with a water evaporation rate Vp = 0% in the table in Figure 32(a) is selected.

[0183] The upper limit number of times Nth is selected based on the water evaporation rate Vp obtained in S2019 and the ink adhesion rate S obtained in S2010, which will be described later. When no water evaporation has occurred after the device has been used, the water evaporation rate Vp = 0% in the table of Figure 32(b), and the upper limit number of times Nth is set based on the ink adhesion rate S obtained in S2010.

[0184] When the device is first used and no moisture evaporation has occurred, the ink-laden cap 501 remains open for a certain period of time. Even if the moisture in the ink adhering to the ink-laden cap 501 evaporates, the amount of moisture in the ink in the ink path at that time remains unchanged. After that, when the ink-laden cap 501 is closed to perform the humidification circulation mode (sustaining circulation mode), the dried ink adhering to the ink-laden cap 501 removes moisture from the ink in the ink path through the ejection ports. Therefore, by going through the humidification circulation mode (sustaining circulation mode), the amount of moisture in the ink in the ink path decreases, and the ink near the ejection ports thickens. Therefore, from the second time onward, the first circulation interval T1 and the upper limit number of times Nth are determined based on the moisture that evaporated while the ink-laden cap 501 was open.

[0185] In S2019, the CPU 302 derives the water evaporation rate Vp from the amount of water evaporation Vcap of the ink adhering to the inside of the leaving cap acquired in S2013. Thereafter, the CPU 302 performs the retention circulation mode in S2020, and ends the process.

[0186] In this way, the amount of water evaporation may be obtained according to the time that the leaving cap 501 is open, and the first circulation interval T1 and the upper limit number of times Nth may be determined.

[0187] Eighth Embodiment Hereinafter, an eighth embodiment of the present invention will be described with reference to the drawings. Note that the basic configuration of this embodiment is the same as that of the fourth embodiment, so the following will describe the characteristic configuration.

[0188] In the above embodiments, a configuration including a standing cap 501 and a recovery cap 211 was described. However, in this embodiment, a standing cap is not provided due to considerations of the size and cost of the main body, and a single cap is used for both recovery and standing. In this case, a large amount of ink is always present in the cap. When a single cap is used for both recovery and standing, the amount of ink adhering to the cap is greater than when a standing cap is provided. Therefore, it is desirable to make the first circulation interval T1 in the humidified circulation mode shorter and the upper limit number of times Nth larger than in embodiments 1 to 4.

[0189] Figure 33 is a flowchart showing the humidification control inside the cap in this embodiment. The series of processes shown in Figure 33 are performed by the CPU 302 of the recording device 1201 expanding and executing program code stored in the memory 303. Alternatively, some or all of the functions of the steps in Figure 33 may be realized by hardware such as an ASIC or electronic circuit. Note that the symbol "S" in the explanation of each process indicates a step in the flowchart. Below, the humidification control inside the standing cap in this embodiment will be explained using the flowchart in Figure 33.

[0190] When humidification control inside the standing cap is started, the CPU 302 controls the lifting mechanism of the recovery / standing cap in S2210 to place the recovery / standing cap (not shown) in a cap-closed state. The CPU 302 starts a timer Tm in S2220 and sets the number of circulations N to 0 in S2230. This timer Tm is provided in the recording device 1201 and counts the duration of the cap-closed state of the recovery / standing cap (referred to as the capping time).

[0191] The recording control unit 301 can acquire the capping time at any timing. Next, in S2230, the CPU 302 sets the circulation count N to 0. In S2240, the CPU 302 controls the pump 408 in the print head 1210 to transition to a "humidification circulation mode" in which intermittent circulation is performed every first circulation interval T1 (30 minutes in this embodiment) until the upper limit number Nth of 96 times is reached. After the humidification circulation mode is completed, in S2250, the CPU 302 transitions to a "maintenance circulation mode" in which intermittent circulation is performed every second circulation interval T2 (24 hours in this embodiment). In this embodiment, the circulation time for one cycle is 10 seconds in either mode.

[0192] The upper limit of the circulation frequency may be set within a range that allows sufficient humidification of the ink adhering to the cap. As described above, by setting an upper limit of the circulation frequency, excessive circulation can be prevented, thereby preventing a poor user experience.

[0193] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0194] <Summary of the embodiment> The above-described embodiment discloses the following liquid ejection device. (Item 1) A liquid ejection device, a capping means for covering a discharge port surface on which a discharge port of a discharge means for discharging a liquid is provided, and capable of capping the discharge port surface; a circulation means that communicates with the discharge port of the discharge means and circulates the liquid through a circulation path that includes a storage section that stores the liquid to be discharged from the discharge port, the circulation means performs an operation of circulating the liquid through the circulation path while the cap means is covering the discharge port surface. A liquid ejection device characterized by: (Item 2) The capping means is a first cap that does not receive the liquid; The circulation means is The operation is performed in a state where the first cap covers the ejection port surface. 2. The liquid ejection device according to item 1, (Item 3) The capping means is a second cap that covers the ejection port surface and receives the liquid; 3. The liquid ejection device according to item 2, (Item 4) a suction means for sucking the liquid from the discharge port surface through the second cap; 4. The liquid ejection device according to item 3, (Item 5) The suction means a suction tube connected to the second cap; a decompression pump that decompresses a second cap space formed by the second cap covering the discharge port surface via the suction tube. 5. The liquid ejection device according to item 4, (Item 6) The operation of the circulation means is The operation is stopped based on a condition related to a humidity change in a first cap space formed by the first cap covering the ejection port surface. 6. The liquid ejection device according to any one of items 2 to 5, characterized in that: (Item 7) The operation of the circulation means is The circulation of the liquid through the circulation path is stopped on the condition that a first time period has elapsed since the circulation of the liquid was started. 6. The liquid ejection device according to any one of items 1 to 5, characterized in that: (Item 8) The operation of the circulation means is After being stopped due to the lapse of the first time period, it is resumed when a second time period has elapsed. 8. The liquid ejection device according to item 7, (Item 9) a measuring means for measuring humidity in a first cap space formed by the first cap covering the ejection port surface, The operation of the circulation means is The operation is stopped on the condition that the humidity of the first cap space measured by the measuring means reaches a first value. 7. The liquid ejection device according to any one of items 2 to 6, characterized in that: (Item 10) The operation of the circulation means is After being stopped due to the humidity of the first cap space measured by the measuring means reaching the first value, the measurement is resumed when the humidity of the first cap space measured by the measuring means reaches a second value lower than the first value. 10. The liquid ejection device according to item 9, (Item 11) The first cap comprises: a communication passage that communicates a first cap space formed by the first cap covering the ejection port surface with an external space; 11. The liquid ejection device according to any one of items 2 to 10, characterized in that: (Item 12) The communication passage has a labyrinth shape. Item 12. The liquid ejection device according to item 11. (Item 13) The first cap comprises: Does not have an absorbent body to absorb liquids, 13. The liquid ejection device according to any one of items 2 to 12, characterized in that: (Item 14) The first cap comprises: When the discharge means is left standing, the discharge port surface is covered. 14. The liquid ejection device according to any one of items 2 to 13, (Item 15) The first cap comprises: a cap that does not suction the liquid from the ejection surface when covering the ejection surface; 15. The liquid ejection device according to any one of items 2 to 14, (Item 16) The liquid ejection device a recording device that ejects ink as the liquid onto a recording medium; 16. The liquid ejection device according to any one of items 1 to 15, (Item 17) a control means for controlling the capping means and the circulation means; Equipped with The control means After the capping means caps the discharge port surface, a first circulation mode is executed in which the circulation means intermittently circulates the liquid at first time intervals; 2. The liquid ejection device according to item 1, wherein the first circulation mode is terminated when the number of times the intermittent circulation has been performed in the first circulation mode reaches a first upper limit value. (Item 18) the control means, after executing the first circulation mode, executes a second circulation mode in which the circulation means intermittently circulates the liquid at a second time interval longer than the first time interval; Item 18. The liquid ejection device according to item 17, wherein the second circulation mode is terminated when the number of times the intermittent circulation has been performed in the second circulation mode reaches a second upper limit value. (Item 19) the first time interval is within one hour, and the first upper limit value is 24; Item 19. The liquid ejection device according to item 18, wherein the second time interval is 24 hours and the second upper limit value is 60. (Item 20) Item 18. The liquid ejection device according to item 17, wherein when a signal for the ejection means to eject is input while the ejection outlet surface is capped, the control means causes the circulation means to circulate for a predetermined time period corresponding to the elapsed time after capping and the number of circulations in the first circulation mode. (Item 21) Item 21. The liquid ejection device according to item 20, wherein the control means sets the predetermined time to a longer time the longer the elapsed time after capping, and sets the predetermined time to a shorter time the greater the number of circulations in the first circulation mode. (Item 22) a detecting means for detecting the amount of ink adhering to the cap means; Item 18. The liquid ejection device according to item 17, wherein the control means sets the first upper limit value based on the detection result of the detection means. (Item 23) 23. The liquid ejection apparatus according to item 22, wherein the control unit sets the first upper limit value to a larger value as the amount of ink adhesion detected by the detection unit increases. (Item 24) further comprising an acquisition unit for acquiring a water evaporation rate of the ink in the cap unit; 24. The liquid ejection device according to item 22 or 23, wherein the control unit sets the first time interval and the first upper limit value based on the result of acquisition by the acquisition unit. (Item 25) Item 25. The liquid ejection device according to item 24, wherein the control means sets the first time interval to a smaller value and the first upper limit value to a larger value as the water evaporation rate of the ink in the cap means increases. (Item 26) the capping means includes a recovery cap connected to suction means for sucking the liquid from the discharge port, and a leaving cap for sealing the discharge port, Item 18. The liquid ejection device according to item 17, wherein when the first circulation mode is performed, the control means performs capping with the leaving cap. (Item 27) a capping means for covering a discharge port surface on which a discharge port of a discharge means for discharging a liquid is provided, and capable of capping the discharge port surface; a circulation means that communicates with the discharge port of the discharge means and circulates the liquid through a circulation path that includes a storage section that stores the liquid to be discharged from the discharge port; A method for controlling a liquid ejection device comprising: causing the circulation means to circulate the liquid through the circulation path while the cap means is covering the discharge port surface; A control method comprising:

[0195] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0196] 1 Liquid ejection device: 3 Recording head: 30 Ejection surface: 31 Ejection port: 50 Dry cap: 5S Dry cap space: 51 Communication path: 60 Suction cap: 600 Absorber: 8 Storage section: 9 Circulation unit: 90 Circulation path:

Claims

1. A liquid ejection device, a capping means for covering a discharge port surface on which a discharge port of a discharge means for discharging a liquid is provided, and capable of capping the discharge port surface; a circulation means that communicates with the discharge port of the discharge means and circulates the liquid through a circulation path that includes a storage section that stores the liquid to be discharged from the discharge port, the circulation means performs an operation of circulating the liquid through the circulation path while the cap means is covering the discharge port surface. A liquid ejection device characterized by:

2. The capping means is a first cap that does not receive the liquid; The circulation means is The operation is performed in a state where the first cap covers the ejection port surface. The liquid ejection device according to claim 1 .

3. The capping means is a second cap that covers the ejection port surface and receives the liquid; 3. The liquid ejection device according to claim 2.

4. a suction means for sucking the liquid from the discharge port surface through the second cap; 4. The liquid ejection device according to claim 3.

5. The suction means a suction tube connected to the second cap; a decompression pump that decompresses a second cap space formed by the second cap covering the discharge port surface via the suction tube.

5. The liquid ejection device according to claim 4.

6. The operation of the circulation means is The operation is stopped based on a condition related to a humidity change in a first cap space formed by the first cap covering the ejection port surface.

3. The liquid ejection device according to claim 2.

7. The operation of the circulation means is The circulation of the liquid through the circulation path is stopped on the condition that a first time period has elapsed since the circulation of the liquid was started. The liquid ejection device according to claim 1 .

8. The operation of the circulation means is After being stopped due to the lapse of the first time period, the operation is resumed when a second time period has elapsed.

8. The liquid ejection device according to claim 7.

9. a measuring means for measuring humidity in a first cap space formed by the first cap covering the ejection port surface, The operation of the circulation means is The operation is stopped on the condition that the humidity in the first cap space measured by the measuring means reaches a first value.

3. The liquid ejection device according to claim 2.

10. The operation of the circulation means is After being stopped due to the humidity of the first cap space measured by the measuring means reaching the first value, the measurement is resumed when the humidity of the first cap space measured by the measuring means reaches a second value lower than the first value. The liquid ejection device according to claim 9 .

11. The first cap includes: a communication passage that communicates a first cap space formed by the first cap covering the ejection port surface with an external space; 3. The liquid ejection device according to claim 2.

12. The communication passage has a labyrinth shape. The liquid ejection device according to claim 11 .

13. The first cap includes: Does not have an absorbent body to absorb liquids, 3. The liquid ejection device according to claim 2.

14. The first cap includes: When the discharge means is left standing, the discharge port surface is covered.

3. The liquid ejection device according to claim 2.

15. The first cap includes: a cap that does not suction the liquid from the ejection port surface when covering the ejection port surface; 3. The liquid ejection device according to claim 2.

16. The liquid ejection device a recording device that ejects ink as the liquid onto a recording medium; The liquid ejection device according to claim 1 .

17. a control means for controlling the capping means and the circulation means; The control means After the capping means caps the discharge port surface, a first circulation mode is executed in which the circulation means intermittently circulates the liquid at first time intervals; When the number of times the intermittent circulation has been performed in the first circulation mode reaches a first upper limit value, the first circulation mode is terminated. The liquid ejection device according to claim 1 .

18. The control means After the first circulation mode is executed, a second circulation mode is executed in which the circulation means intermittently circulates the liquid at a second time interval longer than the first time interval; When the number of times the intermittent circulation has been performed in the second circulation mode reaches a second upper limit value, the second circulation mode is terminated.

18. The liquid ejection device according to claim 17.

19. the first time interval is within one hour, and the first upper limit value is 24; The second time interval is 24 hours, and the second upper limit value is 60.

19. The liquid ejection device according to claim 18.

20. The control means When a signal for the discharge means to discharge is input in a state where the discharge port surface is capped, the circulation means is caused to circulate for a predetermined time period corresponding to the elapsed time after capping and the number of circulations in the first circulation mode.

18. The liquid ejection device according to claim 17.

21. The control means The predetermined time is set to a longer time as the elapsed time after capping is longer, and is set to a shorter time as the number of circulations in the first circulation mode is greater.

21. The liquid ejection device according to claim 20.

22. further comprising a detection unit for detecting the amount of ink adhering to the cap unit; The control means setting the first upper limit value based on the detection result of the detection means; 18. The liquid ejection device according to claim 17.

23. The control means The greater the amount of ink adhesion detected by the detection means, the greater the first upper limit value is set to.

23. The liquid ejection device according to claim 22.

24. further comprising an acquisition unit for acquiring a water evaporation rate of the ink in the cap unit; The control means setting the first time interval and the first upper limit value based on the result of acquisition by the acquisition means; 23. The liquid ejection device according to claim 22.

25. The control means the first time interval is set to a smaller value and the first upper limit value is set to a larger value as the water evaporation rate of the ink in the cap means increases.

25. The liquid ejection device according to claim 24.

26. The capping means is a recovery cap connected to a suction means for sucking liquid from the discharge port, and a leaving cap for sealing the discharge port, When the first circulation mode is performed, the control means performs capping with the leaving cap.

18. The liquid ejection device according to claim 17.

27. a capping means for covering a discharge port surface on which a discharge port of a discharge means for discharging a liquid is provided, and capable of capping the discharge port surface; a circulation means that communicates with the discharge port of the discharge means and circulates the liquid through a circulation path that includes a storage portion that stores the liquid to be discharged from the discharge port, causing the circulation means to circulate the liquid through the circulation path while the cap means is covering the discharge port surface; A control method comprising:

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