Recording device, control method, and program

Abstract

To bring a recording head into a liquid ejectable state by reducing waste ink.SOLUTION: A recording device according to the present invention has a recording head which has: an ejection port surface provided with an ejection port; a recording element which generates energy for ejecting liquid from the ejection port; a pressure chamber provided at a position facing the recording element; a first flow channel communicating with the pressure chamber via a first port different from the ejection port and a second flow channel communicating with the pressure chamber via a second port different from the ejection port, wherein the liquid is ejected from the ejection port through the pressure chamber. The recording device further has; acquisition means which acquires information concerning a time during which the liquid is not ejected from the ejection port; and circulation means which circulates the liquid so that the liquid flows from the first flow channel to the second flow channel through the pressure chamber. When the time indicated by information acquired by the acquisition means exceeds a prescribed time, the circulation means circulates the liquid from the first flow channel to the second flow channel through the pressure chamber.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a recording apparatus, a control method, and a program. [Background technology]

[0002] Patent Document 1 discloses a printer that clears nozzle clogging by forcibly discharging an amount of ink according to the available moisture content in the ink. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-44337 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technique disclosed in Patent Document 1, ink is discharged to eliminate clogging, which results in the generation of waste ink.

[0005] In view of the above problems, an object of the present invention is to reduce waste ink while enabling a print head to eject liquid such as ink. [Means for solving the problem]

[0006] The present invention relates to a liquid ejection head, comprising: an ejection port surface provided with ejection ports for ejecting liquid; a recording element that generates energy for ejecting liquid from the ejection ports; The above Recording element and Between the discharge port A pressure chamber provided ,before a first flow path communicating with the pressure chamber; ,before a second flow path communicating with the pressure chamber, the liquid being ejected from the ejection port through the pressure chamber; and a capping mechanism for capping the ejection port surface. ,liquidand a circulation means for circulating the liquid, and when the time during which the discharge port surface is capped by the cap mechanism exceeds a predetermined time, the circulation means circulates the liquid from the first flow path through the pressure chamber. No discharge from the discharge port To the second flow path and liquid This is a recording device that features circulation throughout the body. Effect of the Invention

[0007] According to the present invention, it is possible to reduce waste ink while enabling the recording head to eject liquid. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing the recording device in a standby state. [Diagram 2] FIG. 2 is a block diagram showing a control configuration of the printing apparatus. [Diagram 3] FIG. 2 is a diagram showing the recording device in a recording state. [Figure 4] 13(a) to 13(c) are diagrams showing the transport path of a recording medium fed from a first cassette. [Diagram 5] 13(a) to 13(c) are diagrams showing the transport path of the recording medium fed from the second cassette. [Figure 6] 13A to 13D are diagrams showing the transport path when a recording operation is performed on the back surface of the recording medium. [Figure 7] FIG. 2 is a diagram showing the recording apparatus in a maintenance state. [Figure 8] 1A and 1B are perspective views showing the configuration of a maintenance unit. [Figure 9] FIG. 2 is a diagram showing an ink supply unit. [Figure 10] 3A and 3B are diagrams illustrating the configuration of the ejection units of the recording element substrate. [Figure 11] 4 is a flowchart of a timer circulation process in the first embodiment. [Figure 12] FIG. 4 is an explanatory diagram of a timer circulation process in the first embodiment. [Figure 13]13 is a flowchart of a timer circulation process in the second embodiment. [Figure 14] FIG. 11 is an explanatory diagram of a timer circulation process in the second embodiment. [Figure 15] FIG. 13 is an explanatory diagram of a timer circulation process in the third embodiment. [Figure 16] FIG. 13 is an explanatory diagram of a timer circulation process in the fourth embodiment. [Figure 17] FIG. 13 is an explanatory diagram of a timer circulation process in the fifth embodiment. [Figure 18] FIG. 23 is an explanatory diagram of a timer circulation process in the sixth embodiment. [Figure 19] FIG. 23 is an explanatory diagram of a timer circulation process in the seventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a liquid ejection head and a liquid ejection device according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiment, an inkjet recording head and an inkjet recording device that ejects ink will be described in a specific configuration, but the present invention is not limited to this. For example, the present invention is not limited to a line head printer, but can also be applied to a serial head printer. In addition, the liquid ejection head, liquid ejection device, and liquid supply method of the present invention can be applied to devices such as printers, copiers, facsimiles with communication systems, word processors with printer units, and industrial recording devices combined with various processing devices. For example, it can also be used for applications such as biochip production and electronic circuit printing. The embodiments described below are specific examples of the present invention, and therefore various technically preferable limitations are attached. However, as long as they are in line with the idea of ​​the present invention, the embodiments are not limited to the embodiments described below or other specific methods.

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

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

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

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

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

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

[0016] The ink tank units 14 store four colors of ink to be supplied to the recording head 8. Here, the four colors of ink refer to cyan (C), magenta (M), yellow (Y), and black (K) ink. The ink supply unit 15 is provided midway through the flow path connecting the ink tank units 14 and the recording head 8, and adjusts the pressure and flow rate of the ink in the recording head 8 to appropriate ranges. The recording device 1 has a circulation type ink supply system, and the ink supply unit 15 adjusts the pressure of the ink supplied to the recording head 8 and the flow rate of the ink collected from the recording head 8 to appropriate ranges.

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

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

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

[0020] The recording device 1 may obtain image data from the host device 400 via wireless communication or wired communication, or may obtain image data from an external storage device (such as a USB memory) connected to the recording device 1. The communication method used for wireless communication or wired communication is not limited. For example, Wi-Fi (Wireless Fidelity) (registered trademark) or Bluetooth (registered trademark) can be used as a communication method used for wireless communication. Also, USB (Universal Serial Bus) or the like can be used as a communication method used for wired communication. Also, for example, when a read command is input from the host device 400, the main controller 101 transmits the command to the scanner engine unit 300 via the scanner engine I / F 109.

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

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

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

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

[0025] <Operation of the recording device in recording mode> Fig. 3 shows the recording device 1 in a recording state. Compared to the standby state shown in Fig. 1, the cap unit 10 is spaced away from the nozzle surface 8a of the recording head 8, and the nozzle surface 8a faces the platen 9. The plane of the platen 9 is inclined at about 45 degrees to the horizontal direction, and the nozzle surface 8a of the recording head 8 in the recording position is also inclined at about 45 degrees to the horizontal direction so that the distance from the platen 9 is maintained constant.

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

[0027] Next, a description will be given of the transport path of the recording medium S in the printing section 2. When a recording command is input, the print controller 202 first uses the maintenance control section 210 and the head carriage control section 208 to move the recording head 8 to the recording position shown in Fig. 3. Then, the print controller 202 uses the transport control section 207 to drive either the first feeding unit 6A or the second feeding unit 6B in accordance with the recording command, and feeds the recording medium S.

[0028] 4(a) to 4(c) are diagrams showing the conveying path when A4-sized recording media S housed in the first cassette 5A are fed. The topmost recording medium S in the first cassette 5A is separated from the second and subsequent recording media by the first feeding unit 6A, and is conveyed toward the recording area P between the platen 9 and the recording head 8 while being nipped between the conveying roller 7 and the pinch roller 7a. FIG. 4(a) shows the conveying state just before the leading edge of the recording medium S reaches the recording area P. The traveling direction of the recording medium S is changed from the horizontal direction (x direction) to a direction inclined at about 45 degrees from the horizontal direction while being fed by the first feeding unit 6A and reaching the recording area P.

[0029] In the recording area P, ink is ejected from a plurality of ejection ports provided in the recording head 8 toward the recording medium S. The back surface of the recording medium S in the area where the ink is applied is supported by a platen 9, and the distance between the ejection port surface 8a and the recording medium S is kept constant. The recording medium S after the ink is applied passes the left side of the flapper 11, the leading end of which is tilted to the right, while being guided by the transport roller 7 and the spur 7b, and is transported vertically upward in the recording device 1 along the guide 18. FIG. 4(b) shows a state in which the leading end of the recording medium S passes through the recording area P and is transported vertically upward. The traveling direction of the recording medium S is changed vertically upward from the position of the recording area P, which is tilted at about 45 degrees from the horizontal direction, by the transport roller 7 and the spur 7b.

[0030] The recording medium S is transported vertically upward, and then discharged onto the discharge tray 13 by the discharge rollers 12 and spurs 7b. Fig. 4(c) shows the state in which the leading edge of the recording medium S passes through the discharge rollers 12 and is discharged onto the discharge tray 13. The discharged recording medium S is held on the discharge tray 13 with the side on which the image is recorded by the recording head 8 facing down.

[0031] 5(a) to 5(c) are diagrams showing the conveying path when A3 size recording media S contained in the second cassette 5B are fed. The top recording medium S in the second cassette 5B is separated from the second and subsequent recording media by the second feeding unit 6B, and is conveyed toward the recording area P between the platen 9 and the recording head 8 while being nipped between the conveying roller 7 and the pinch roller 7a.

[0032] 5(a) shows a conveying state immediately before the leading edge of the recording medium S reaches the recording area P. A plurality of conveying rollers 7, pinch rollers 7a, and an inner guide 19 are arranged on the conveying path from when the recording medium S is fed by the second feeding unit 6B to when it reaches the recording area P, so that the recording medium S is conveyed to the platen 9 while being curved in an S shape.

[0033] The subsequent transport path is the same as that of the A4-sized recording medium S shown in Figures 4(b) and (c). Figure 5(b) shows the state in which the leading edge of the recording medium S passes through the recording area P and is transported vertically upward. Figure 5(c) shows the state in which the leading edge of the recording medium S passes through the discharge rollers 12 and is discharged onto the discharge tray 13.

[0034] Figures 6(a) to (d) show the transport path when performing a recording operation (double-sided recording) on ​​the back side (second side) of an A4-sized recording medium S. When performing double-sided recording, the first side (front side) is recorded, and then the recording operation is performed on the second side (back side). The transport process when recording on the first side is the same as in Figures 4(a) to (c), so a description thereof will be omitted here. Hereinafter, the transport process from Figure 4(c) onwards will be described.

[0035] When the recording operation on the first side by the recording head 8 is completed and the rear end of the recording medium S passes the flapper 11, the print controller 202 rotates the transport roller 7 in the reverse direction to transport the recording medium S into the recording device 1. At this time, the flapper 11 is controlled by an actuator (not shown) so that its leading end is tilted to the left, so that the leading end of the recording medium S (the rear end in the recording operation on the first side) passes the right side of the flapper 11 and is transported vertically downward. FIG. 6(a) shows the state in which the leading end of the recording medium S (the rear end in the recording operation on the first side) passes the right side of the flapper 11.

[0036] The recording medium S is then transported along the curved outer peripheral surface of the inner guide 19, and is transported again to the recording area P between the recording head 8 and the platen 9. At this time, the second surface of the recording medium S faces the ejection port surface 8a of the recording head 8. Fig. 6(b) shows the transport state immediately before the leading edge of the recording medium S reaches the recording area P for the recording operation on the second surface.

[0037] The transport path thereafter is the same as that shown in Figures 4(b) and (c) when recording on the first side. Figure 6(c) shows the state in which the leading edge of the recording medium S passes through the recording area P and is transported vertically upward. At this time, the flapper 11 is controlled by an actuator (not shown) so that the leading edge moves to a position tilted to the right. Figure 6(d) shows the state in which the leading edge of the recording medium S passes through the discharge rollers 12 and is discharged to the discharge tray 13.

[0038] <Maintenance operations for recording heads> Next, a description will be given of the maintenance operation for the recording head 8. As described in Fig. 1, the maintenance unit 16 includes a cap unit 10 and a wiping unit 17, and performs the maintenance operation by operating these at a predetermined timing.

[0039] Fig. 7 is a diagram showing the recording device 1 in a maintenance state. When moving the recording head 8 from the standby position shown in Fig. 1 to the maintenance position shown in Fig. 7, the print controller 202 moves the recording head 8 upward in the vertical direction and moves the cap unit 10 downward in the vertical direction. Then, the print controller 202 moves the wiping unit 17 from the retracted position to the right in Fig. 7. After that, the print controller 202 moves the recording head 8 downward in the vertical direction to a maintenance position where maintenance operation is possible.

[0040] On the other hand, when the recording head 8 moves from the recording position shown in Fig. 3 to the maintenance position shown in Fig. 7, the print controller 202 moves the recording head 8 vertically upward while rotating it 45 degrees. Then, the print controller 202 moves the wiping unit 17 from the retracted position to the right. After that, the print controller 202 moves the recording head 8 vertically downward to a maintenance position where the maintenance operation by the maintenance unit 16 can be performed.

[0041] FIG. 8(a) is a perspective view showing a state in which the maintenance unit 16 is in a standby position, and FIG. 8(b) is a perspective view showing a state in which the maintenance unit 16 is in a maintenance position. FIG. 8(a) corresponds to FIG. 1, and FIG. 8(b) corresponds to FIG. 7. When the recording head 8 is in the standby position, the maintenance unit 16 is in the standby position shown in FIG. 8(a), the cap unit 10 moves vertically upward, and the wiping unit 17 is stored inside the maintenance unit 16. The cap unit 10 has a box-shaped cap member 10a extending in the y direction, and by bringing this into close contact with the discharge port surface 8a of the recording head 8, it is possible to suppress the evaporation of ink from the discharge port. The cap member 10a is provided with an absorber capable of absorbing and holding a predetermined amount of ink. The cap unit 10 also has a function of collecting ink discharged by the cap member 10a during preliminary discharge or the like, and causing the collected ink to be sucked into a suction pump (not shown) (cap suction).

[0042] 8(b), the cap unit 10 has moved vertically downward, and the wiping unit 17 has been pulled out from the maintenance unit 16. The wiping unit 17 includes two wiper units: a blade wiper unit 171 and a vacuum wiper unit 172.

[0043] In the blade wiper unit 171, a blade wiper 171a for wiping the ejection port surface 8a along the x direction is arranged in the y direction by a length corresponding to the arrangement area of ​​the ejection ports. When performing a wiping operation using the blade wiper unit 171, the wiping unit 17 moves the blade wiper unit 171 in the x direction with the recording head 8 positioned at a height that allows it to abut against the blade wiper 171a. With this movement, ink and the like adhering to the ejection port surface 8a is wiped off by the blade wiper 171a.

[0044] A wet wiper cleaner 16a is disposed at the entrance of the maintenance unit 16 when the blade wiper 171a is stored, for removing ink adhering to the blade wiper 171a and applying wet liquid to the blade wiper 171a. Every time the blade wiper 171a is stored in the maintenance unit 16, the wet wiper cleaner 16a removes adhering matter and applies wet liquid to the blade wiper 171a. When the ejection port surface 8a is wiped next time, the wet liquid is transferred to the ejection port surface 8a, improving the slipperiness between the ejection port surface 8a and the blade wiper 171a.

[0045] On the other hand, the vacuum wiper unit 172 has a flat plate 172a having an opening extending in the y direction, a carriage 172b movable in the y direction within the opening, and a vacuum wiper 172c mounted on the carriage 172b. The vacuum wiper 172c is arranged so that it can wipe the ejection port surface 8a in the y direction as the carriage 172b moves. A suction port connected to a suction pump (not shown) is formed at the tip of the vacuum wiper 172c. Therefore, when the carriage 172b is moved in the y direction while the suction pump is operated, the ink and the like adhering to the ejection port surface 8a of the recording head 8 is sucked into the suction port while being wiped by the vacuum wiper 172c. At this time, the positioning pins 172d provided on both ends of the flat plate 172a and the opening are used to align the ejection port surface 8a with respect to the vacuum wiper 172c.

[0046] The wiping unit 17 can perform a first wiping process in which the wiping operation is performed by the blade wiper unit 171 but not by the vacuum wiper unit 172, and a second wiping process in which both wiping processes are performed in sequence. When performing the first wiping process, the print controller 202 first pulls out the wiping unit 17 from the maintenance unit 16 in a state in which the recording head 8 is retracted vertically upward from the maintenance position in FIG. 7. Then, the print controller 202 moves the recording head 8 vertically downward to a position where it can abut against the blade wiper 171a, and then moves the wiping unit 17 into the maintenance unit 16. By this movement, ink and the like adhering to the ejection port surface 8a are wiped off by the blade wiper 171a. That is, the blade wiper 171a wipes the ejection port surface 8a when it moves into the maintenance unit 16 from the position where it is pulled out from the maintenance unit 16.

[0047] When the blade wiper unit 171 is stored, the print controller 202 then moves the cap unit 10 vertically upward to bring the cap member 10a into close contact with the ejection port surface 8a of the recording head 8. Then, the print controller 202 drives the recording head 8 in this state to perform preliminary ejection, and sucks the ink collected in the cap member 10a with the suction pump.

[0048] On the other hand, when performing the second wiping process, the print controller 202 first slides and pulls out the wiping unit 17 from the maintenance unit 16 while retracting the recording head 8 vertically upward from the maintenance position in FIG. 7. Then, the print controller 202 moves the recording head 8 vertically downward to a position where it can abut against the blade wiper 171a, and then moves the wiping unit 17 into the maintenance unit 16. This allows the blade wiper 171a to perform a wiping operation on the discharge port surface 8a. Next, the print controller 202 slides and pulls out the wiping unit 17 from the maintenance unit 16 to a predetermined position while retracting the recording head 8 vertically upward from the maintenance position in FIG. 7 again. Next, the print controller 202 uses the flat plate 172a and the positioning pin 172d to position the discharge port surface 8a and the vacuum wiper unit 172 while lowering the recording head 8 to the wiping position shown in FIG. 7. Thereafter, the print controller 202 executes the wiping operation by the above-mentioned vacuum wiper unit 172. The print controller 202 retracts the recording head 8 vertically upward and stores the wiping unit 17, and then performs the preliminary ejection into the cap member by the cap unit 10 and the suction operation of the collected ink, similar to the first wiping process.

[0049] <Ink supply unit> Fig. 9 is a diagram showing the ink supply unit 15 employed in the inkjet recording apparatus 1 of this embodiment. The ink supply unit 15 is configured to supply ink from the ink tank unit 14 to the recording head 8. Here, a configuration for one color of ink is shown, but in reality, such a configuration is prepared for each ink color. The ink supply unit 15 is basically controlled by the ink supply control unit 209 shown in Fig. 2. Each configuration of the unit will be described below.

[0050] Ink mainly circulates between the subtank 151 and the recording head 8 (head unit in FIG. 9). In the head unit 8, ink is ejected based on image data, and ink that is not ejected is collected back into the subtank 151.

[0051] The subtank 151, which contains a predetermined amount of ink, is connected to a supply flow path C2 for supplying ink to the head unit 8 and a recovery flow path C4 for recovering ink from the head unit 8. In other words, the subtank 151, the supply flow path C2, the head unit 8, and the recovery flow path C4 form a circulation path through which the ink circulates.

[0052] The subtank 151 is provided with a liquid level detection means 151a consisting of multiple pins, and the ink supply control unit 209 can detect the presence or absence of a conductive current between these multiple pins to grasp the height of the ink liquid level, i.e., the amount of ink remaining in the subtank 151. The pressure reduction pump P0 is a negative pressure generation source for reducing the pressure inside the subtank 151. The atmosphere release valve V0 is a valve for switching whether or not the inside of the subtank 151 is connected to the atmosphere.

[0053] The main tank 141 is a tank that contains ink to be supplied to the sub tank 151. The main tank 141 is made of a flexible member, and ink is filled into the sub tank 151 by changing the volume of the flexible member. The main tank 141 is configured to be detachable from the recording apparatus body. A tank supply valve V1 for switching the connection between the sub tank 151 and the main tank 141 is provided in the middle of a tank connection flow path C1 that connects the sub tank 151 and the main tank 141.

[0054] With the above configuration, when the ink level detection means 151a detects that the ink in the subtank 151 is less than a predetermined amount, the ink supply control unit 209 closes the atmosphere release valve V0, supply valve V2, recovery valve V4, and head replacement valve V5, and opens the tank supply valve V1. In this state, the ink supply control unit 209 operates the pressure reduction pump P0. This creates a negative pressure inside the subtank 151, and ink is supplied from the main tank 141 to the subtank 151. When the ink level detection means 151a detects that the ink in the subtank 151 has exceeded a predetermined amount, the ink supply control unit 209 closes the tank supply valve V1 and stops the pressure reduction pump P0.

[0055] The supply flow path C2 is a flow path for supplying ink from the subtank 151 to the head unit 8, and a supply pump P1 and a supply valve V2 are arranged along the way. During a recording operation, the supply pump P1 is driven with the supply valve V2 open, so that ink can be circulated in the circulation path while being supplied to the head unit 8. The amount of ink ejected per unit time by the head unit 8 varies according to image data. The flow rate of the supply pump P1 is determined so as to be able to handle the case where the head unit 8 performs an ejection operation that maximizes the amount of ink ejected per unit time.

[0056] The relief flow path C3 is upstream of the supply valve V2 and is a flow path that connects the upstream and downstream sides of the supply pump P1. A relief valve V3, which is a differential pressure valve, is disposed midway along the relief flow path C3. When the ink supply amount per unit time from the supply pump P1 is greater than the sum of the ink discharge amount per unit time of the head unit 8 and the flow rate (amount of ink drawn) per unit time in the recovery pump P2, the relief valve V3 opens according to the pressure acting on itself. This forms a circulating flow path that is composed of a part of the supply flow path C2 and the relief flow path C3. By providing the above-mentioned configuration of the relief flow path C3, the ink supply amount to the head unit 8 is adjusted according to the ink discharge amount in the head unit 8, and the flow pressure in the circulation path can be stabilized regardless of the image data.

[0057] The recovery flow path C4 is a flow path for recovering ink from the head unit 8 to the subtank 151, and a recovery pump P2 and a recovery valve V4 are arranged along the way. When circulating ink in the circulation path, the recovery pump P2 serves as a negative pressure generating source to suck ink from the head unit 8. By driving the recovery pump P2, an appropriate pressure difference is generated between the IN flow path 80b and the OUT flow path 80c in the head unit 8, and ink can be circulated between the IN flow path 80b and the OUT flow path 80c. The flow path configuration in the head unit 8 will be explained in detail later.

[0058] The recovery valve V4 is a valve for preventing backflow when a printing operation is not being performed, that is, when ink is not circulating in the circulation path. In the circulation path of this embodiment, the subtank 151 is disposed vertically above the head unit 8 (see FIG. 1). Therefore, when the supply pump P1 and the recovery pump P2 are not driven, there is a risk that ink will flow back from the subtank 151 to the head unit 8 due to the head difference between the subtank 151 and the head unit 8. To prevent such backflow, in this embodiment, a recovery valve V4 is provided in the recovery flow path C4.

[0059] Similarly, the supply valve V2 also functions as a valve for preventing the backflow of ink from the subtank 151 to the head unit 8 when no printing operation is being performed, i.e., when no ink is circulating in the circulation path.

[0060] The head replacement flow path C5 is a flow path that connects the supply flow path C2 and the air layer (a portion where ink is not stored) of the subtank 151, and a head replacement valve V5 is disposed in the middle of the flow path. One end of the head replacement flow path C5 is connected to the upstream of the head unit 8 in the supply flow path C2, and the other end is connected to the upper part of the subtank 151 and communicates with the internal air layer. The head replacement flow path C5 is used when recovering ink from the head unit 8 in use, such as when replacing the head unit 8 or when transporting the recording device 1. The head replacement valve V5 is controlled by the ink supply control unit 209 so as to close except when initially filling the recording device 1 with ink or recovering ink from the head unit 8. The above-mentioned supply valve V2 is provided in the supply flow path C2 between the connection part with the head replacement flow path C5 and the connection part with the relief flow path C3.

[0061] Next, a description will be given of the flow path configuration within the head unit 8. The ink supplied to the head unit 8 from the supply flow path C2 passes through a filter 83, and is then supplied to a first negative pressure control unit 81 that generates a weak negative pressure, and a second negative pressure control unit 82 that generates a strong negative pressure. The pressures in the first negative pressure control unit 81 and the second negative pressure control unit 82 are generated within an appropriate range by driving the recovery pump P2.

[0062] In the ink ejection unit 80, a plurality of recording element substrates 80a are arranged, each having a plurality of ejection sections each having an ejection port, and a long ejection port array is formed. A common supply flow path 80b (IN flow path) for guiding ink supplied from the first negative pressure control unit 81 and a common recovery flow path 80c (OUT flow path) for guiding ink supplied from the second negative pressure control unit 82 also extend in the arrangement direction of the recording element substrates 80a. Furthermore, each recording element substrate 80a is formed with an individual supply flow path connected to the common supply flow path 80b and an individual recovery flow path connected to the common recovery flow path 80c. Therefore, in each recording element substrate 80a, a flow of ink is generated in which ink flows in from the common supply flow path 80b, which has a relatively weak negative pressure, and flows out to the common recovery flow path 80c, which has a relatively strong negative pressure. When an ejection operation is performed on the recording element substrate 80a, a portion of the ink moving from the common supply flow path 80b to the common recovery flow path 80c is discharged by being ejected from the ejection port, but the ink that is not ejected moves to the recovery flow path C4 via the common recovery flow path 80c.

[0063] When performing a recording operation with the above configuration, the ink supply control unit 209 closes the tank supply valve V1 and the head replacement valve V5, opens the atmosphere release valve V0, the supply valve V2, and the recovery valve V4, and drives the supply pump P1 and the recovery pump P2. This establishes a circulation path from the subtank 151 to the supply flow path C2 to the head unit 8 to the recovery flow path C4 to the subtank 151. When the amount of ink supplied per unit time from the supply pump P1 is greater than the sum of the ejection amount per unit time of the head unit 8 and the flow rate per unit time of the recovery pump P2, ink flows from the supply flow path C2 to the relief flow path C3. This adjusts the flow rate of ink flowing from the supply flow path C2 to the head unit 8.

[0064] When no recording operation is being performed, the ink supply control unit 209 stops the supply pump P1 and the recovery pump P2, and closes the atmosphere release valve V0, the supply valve V2, and the recovery valve V4. This stops the flow of ink inside the head unit 8, and also suppresses backflow due to the head difference between the subtank 151 and the head unit 8. Closing the atmosphere release valve V0 also suppresses ink leakage from the subtank 151 and evaporation of ink.

[0065] When recovering ink from the head unit 8, the ink supply control unit 209 closes the tank supply valve V1, supply valve V2, and recovery valve V4, opens the atmosphere release valve V0 and head replacement valve V5, and drives the pressure reducing pump P0. This creates a negative pressure state inside the subtank 151, and the ink in the head unit 8 is recovered to the subtank 151 via the head replacement flow path C5. In this way, the head replacement valve V5 is closed during normal recording operations and standby, and is a valve that is opened when recovering ink from the head unit 8. However, the head replacement valve V5 is also opened when filling the head replacement flow path C5 with ink during initial filling of the head unit 8.

[0066] <About the discharge section> Fig. 10(a) is a schematic plan view of an enlarged portion of the recording element substrate 80a, and Fig. 10(b) is a schematic cross-sectional view taken along the cross-sectional line Xb-Xb in Fig. 10(a). The recording element substrate 80a is provided with pressure chambers 1005 filled with ink and ejection ports 1006 for ejecting ink. In the pressure chambers 1005, recording elements 1004 are provided at positions facing the ejection ports 1006. In addition, the recording element substrate 80a is provided with a plurality of individual supply flow paths 1008 connected to the common supply flow path 80b and individual recovery flow paths 1009 connected to the common recovery flow path 80c, each for each ejection port 1006.

[0067] With the above-mentioned configuration, in the recording element substrate 80a, a flow of ink is generated in which the ink flows in through the common supply flow path 80b, which has a relatively weak negative pressure (high pressure), and flows out to the common recovery flow path 80c, which has a relatively strong negative pressure (low pressure). More specifically, the ink flows in the order of the common supply flow path 80b → the individual supply flow path 1008 → the pressure chamber 1005 → the individual recovery flow path 1009 → the common recovery flow path 80c. When ink is ejected by the recording element 1004, a part of the ink moving from the common supply flow path 80b to the common recovery flow path 80c is ejected from the ejection port 1006 and discharged to the outside of the head unit 8. On the other hand, the ink that is not ejected from the ejection port 1006 is recovered to the recovery flow path C4 via the common recovery flow path 80c.

[0068] <About pre-ejection> Preliminary ejection is an operation for discharging the ink that has been pushed into the ejection port by the wiping process and mixed with the ink at a position unrelated to the recording. Preliminary ejection is performed after the first wiping process or the second wiping process described above. This is because the ejection port rows are wiped sequentially in the wiping process, and during a series of wiping operations, the ink wiped off from the ejection port row at the front stage adheres to the ejection port row at the time of wiping the ejection port row at the rear stage, causing mixed ink to remain. Therefore, after the wiping process, preliminary ejection is performed on the cap member 10a. This preliminary ejection discharges the ink that has mixed with the ink in the ejection port.

[0069] Based on the basic configuration described above, preferred embodiments of the present invention will now be described.

[0070] [First embodiment] This embodiment assumes a case where the print head (the ejection port surface) is capped with a cap mechanism for a long period of time. In such a cap closed state, ink evaporation proceeds, although at a slower rate than in the cap open state. Therefore, even in the cap closed state, if ink evaporation proceeds over a long period of time, concentrated ink may accumulate in the ejection port, making it difficult to eject ink from the ejection section. Therefore, in this embodiment, the ink is circulated when a predetermined time has elapsed in the cap closed state, thereby maintaining the inside of the print head in a printable state.

[0071] <About timer cycling> Hereinafter, a process in this embodiment in which the timer counts time and circulates the ink when a predetermined time has elapsed (referred to as timer circulation process) will be described with reference to Fig. 11. Note that the following process is started when the recording apparatus 1 is in a cap-open state, that is, when the ejection port surface 8a is not capped by the cap unit 10 (for example, the state shown in Fig. 3).

[0072] In step S1101, the print controller 202 controls the maintenance control unit 210 to move the cap unit 10 that is not capping the ejection port surface 8a, thereby transitioning the print head 8 from the cap open state to the cap closed state.

[0073] In step S1102, the print controller 202 starts a timer in the cap closed state. This timer is a timer provided in the recording device 1, and counts the duration of the cap closed state (referred to as the capping time). The print controller 202 can obtain the capping time at any timing.

[0074] In step S1103, the print controller 202 determines whether a predetermined time (for example, 6 hours) has elapsed, that is, whether the counter started in step S1102 has counted the predetermined time. If the determination result in step S1103 is true, the process proceeds to step S1104, whereas if the determination result is false, the process proceeds to step S1106.

[0075] In step S1104, the print controller 202 controls the ink supply control unit 209 to circulate the ink in the above-mentioned circulation path. This generates an ink flow in the ejection unit 1000 in the print head 8. FIG. 12 shows how the ink flow 1201 generated in this step causes the thickened ink remaining in the ejection port 1006 to flow out of the individual recovery flow path 1009. The vertical axis corresponds to the time axis, and the time progresses from top to bottom in FIG. 12. As shown in FIG. 12, the ink flow 1201 generated every time a predetermined time elapses causes the ink remaining in the ejection port 1006 to diffuse, and the ejection port 1006 is filled with fresh ink. As a result, the ejection stability (at the ejection port 1006) of the ejection unit 1000 (the characteristic of being able to eject ink stably from the ejection port) is restored.

[0076] In step S1105, the print controller 202 resets the timer.

[0077] In step S1106, the print controller 202 determines whether there is a print command. If the result of this determination is true, the timer circulation process ends. If the result of the determination in step S1106 is false, the process returns to step S1103 and continues with the timer circulation process. The above is the content of the timer circulation process in this embodiment.

[0078] <Effects of this embodiment> According to this embodiment, when the print head 8 is capped with the cap unit 10 for a long period of time, it is possible to prevent the ejection orifices 1006 from being clogged with concentrated ink and ensure ejection stability of the ejection section 1000.

[0079] [Second embodiment] In this embodiment, a case will be described in which the time interval for circulating the ink (referred to as the circulation interval) is changed depending on the installation environment, specifically the temperature and humidity, of the recording device 1. Note that the following mainly describes the differences from the previously described embodiment, and descriptions of the same contents as those of the previously described embodiment will be omitted as appropriate.

[0080] <About timer cycling> The timer circulation process in this embodiment will be described below with reference to FIG.

[0081] In step S1310, the print controller 202 controls the maintenance control unit 210 to move the cap unit 10 that is not capping the ejection port surface 8a, thereby transitioning the recording head 8 from the cap open state to the cap closed state.

[0082] In step S1320, the print controller 202 executes a process (referred to as an in-cap evaporation rate count process) for counting the evaporation rate of the ink in the cap unit 10. Details of the in-cap evaporation rate count process will be described later with reference to FIG. 13(b).

[0083] In step S1330, the print controller 202 derives the circulation interval. Specifically, the print controller 202 functions as a circulation interval deriving means, and derives the value of the circulation interval corresponding to the evaporation rate count value in the cap acquired in step S1320 by referring to a table as shown in FIG. 14(a). When the table shown in FIG. 14(a) is used, for example, when the evaporation rate count value in the cap is 200, the circulation interval is 18 hours. Note that the table in FIG. 14(a) is merely an example, and other tables that hold the value range of the evaporation rate count in the cap and the corresponding circulation interval value may be used. However, in such a table, the circulation interval is generally set to be shorter as the evaporation rate count value in the cap increases. This is because the ink is more likely to thicken as the evaporation rate count value in the cap increases, so that it is necessary to circulate the ink frequently. Note that, although the case of using a table has been described here, the circulation interval may be calculated using a formula into which the evaporation rate count value in the cap is substituted instead of the table.

[0084] In step S1340, the print controller 202 starts a timer that counts the capping time.

[0085] In step S1350, the print controller 202 determines whether the count value of the timer started in step S1340 has reached the rotation interval derived in step S1330. If the determination result in step S1350 is true, the process proceeds to step S1360, whereas if the determination result is false, the process proceeds to step S1380.

[0086] The process of step S1360 is similar to the process of step S1104, and the process of step S1370 is similar to the process of step S1105. After step S1370, the process proceeds to step S1380.

[0087] In step S1380, the print controller 202 determines whether or not there is a print command. If the result of this determination is true, the timer circulation process ends, whereas if the result of this determination is false, the process proceeds to step S1390.

[0088] In step S1390, the print controller 202 determines whether a predetermined time (e.g., one week) has passed since the cap was closed in step S1310. This step is executed to end the timer circulation process when it is expected that the recording device 1 will not be used for a long time and there is little need to keep the interior of the recording head 8 in a printable state. Note that the process of this step may be executed in the flow of the first embodiment. If the determination result in step S1390 is true, the timer circulation process ends, whereas if the determination result is false, the process returns to step S1350 and continues the timer circulation process. The above is the content of the timer circulation process in this embodiment.

[0089] <About the evaporation rate count process inside the cap> The above-mentioned in-cap evaporation rate counting process (step S1320) will be described in detail below with reference to FIG.

[0090] In step S1321, the print controller 202 acquires a current in-cap evaporation rate count value. Here, the in-cap evaporation rate is a parameter indicating the progress of evaporation of ink in the ejection section 1000 capped by the cap unit 10, and is counted by the print controller. The current in-cap evaporation rate count value is stored in the ROM 203.

[0091] In step S1322, the print controller 202 acquires the temperature and humidity of the installation environment of the recording device 1. The recording device 1 is equipped with a thermometer and a hygrometer, and the print controller 202 can acquire the temperature and humidity of the installation environment of the recording device 1 at any timing.

[0092] In step S1323, the print controller 202 derives an evaporation rate coefficient corresponding to the temperature and humidity acquired in step S1322. Hereinafter, a method for deriving this evaporation rate coefficient will be described in detail.

[0093] First, based on the temperature and humidity acquired in step S1322, the state of the installation environment (hereinafter referred to as the temperature and humidity state) is classified using a graph as exemplified in FIG. 14(b). When the graph shown in FIG. 14(b) is used, the state is classified into one of a first temperature and humidity state 1401, a second temperature and humidity state 1402, and a third temperature and humidity state 1403. The first temperature and humidity state 1401 is a low temperature and high humidity state, that is, a state in which ink does not easily condense. The third temperature and humidity state 1403 is a high temperature and low humidity state, that is, a state in which ink easily condenses. The second temperature and humidity state 1402 is an intermediate state between the first temperature and humidity state 1401 and the third temperature and humidity state 1403.

[0094] Next, an evaporation rate coefficient corresponding to the temperature and humidity conditions classified above is derived by referring to a table such as that shown in FIG. 14(c). As shown in FIG. 14(c), the more easily the ink is concentrated, the larger the evaporation rate coefficient. Note that the graph shown in FIG. 14(b) and the table shown in FIG. 14(c) are merely examples, and other graphs and tables may be used. Such graphs for classifying temperature and humidity conditions based on temperature and humidity, and tables holding evaporation rate coefficients for each temperature and humidity condition are stored in advance in ROM 203, and print controller 202 can use them at any time.

[0095] In step S1324, the print controller 202 acquires the cumulative time [minutes] (cap open time) in the cap open state between the previous evaporation rate count process in the cap and the current evaporation rate count process in the cap. Note that the recording device 1 includes a timer that counts the cap open time, and the print controller 202 can acquire the cap open time at any timing.

[0096] In step S1325, the print controller 202 multiplies the evaporation rate coefficient derived in step S1323 by the cap open time acquired in step S1324, and adds the value obtained by this multiplication to the current in-cap evaporation rate count value acquired in step S1321.

[0097] In step S1326, the print controller 202 updates the in-cap evaporation rate count value, specifically, overwrites the in-cap evaporation rate count value stored in the ROM 203 with the value calculated in step S1325 and saves it.

[0098] In step S1327, the print controller 202 determines whether the in-cap evaporation rate count value is equal to or greater than a predetermined threshold value (in this example, equal to or greater than 500). Note that the threshold value of 500 given here is merely an example, and if the table used in step S1330 is changed, the threshold value used in this step will naturally change as well. If the determination result in step S1327 is true, the process proceeds to step S1328, whereas if the determination result is false, the in-cap evaporation rate count process ends (progresses to step S1330).

[0099] In step S1328, the print controller 202 drives the recording element 1004 to perform preliminary ejection of ink. Alternatively, the print controller 202 may control the maintenance control unit 210 to execute cap suction. If the in-cap evaporation rate count value is 500 or more (YES in step S1327), the ink has evaporated considerably, and it is difficult to restore the ejection stability of the ejection unit 1000 by circulation alone. Therefore, preliminary ejection and cap suction are executed in this step to restore the ejection stability.

[0100] In step S1329, the print controller 202 resets the in-cap evaporation rate count value (to 0). After step S1329, the in-cap evaporation rate count process ends (proceeds to step S1330). The above is the content of the in-cap evaporation rate count process in this embodiment.

[0101] <Modifications of this embodiment> In the above example, the circulation interval is derived based on the temperature and humidity of the recording apparatus 1, but the circulation interval may be derived based on either the temperature or the humidity. In the above example, the evaporation rate in the cap is reset in step S1329, but a method of subtracting a count value based on the amount of preliminary ejection or the strength of cap suction may also be used. In addition, if a mechanism capable of deriving ink concentration information as described later in the fourth embodiment is provided, the subtraction value from the evaporation rate in the cap may be changed according to the concentration information.

[0102] <Effects of this embodiment> This embodiment makes it possible to circulate ink at a frequency according to the installation environment of the recording device 1, i.e., temperature and humidity, thereby keeping the recording head 8 in a printable state (ensuring ejection stability of the ejection section 1000).

[0103] [Third embodiment] In the second embodiment, the evaporation rate in the cap is counted taking into account the evaporation of ink in the cap open state, whereas in the present embodiment, the evaporation rate in the cap is counted taking into account the evaporation of ink in the cap closed state.

[0104] <About timer cycling> The timer circulation process in this embodiment will be described below with reference to FIG.

[0105] The processes in steps S1510 to S1560 are similar to those in steps S1310 to S1360.

[0106] In step S1570, the print controller 202 executes an evaporation rate in cap addition process during the cap closing, which adds the fluctuation in the evaporation rate in the cap due to the evaporation of the ink proceeding while the cap is closed to the count value of the evaporation rate in the cap. Details of the evaporation rate in cap count process during the cap closing will be described later with reference to FIG. 15(b).

[0107] The processing in steps S1590 to S1600 is similar to that in steps S1380 to S1390. However, in this embodiment, if NO in step S1600, the process returns to step S1530 and the circulation interval is derived again. In this manner, in this embodiment, the circulation interval is derived each time circulation is performed (step S1560->...->NO in step S1600->step S1530), which makes it possible to perform circulation at an appropriate interval.

[0108] <Additional processing of evaporation rate inside the cap while the cap is closed> Hereinafter, the above-mentioned process of adding the evaporation rate in the cap while the cap is closed (step S1570) will be described in detail with reference to FIG.

[0109] In step S1571, the print controller 202 acquires the current in-cap evaporation rate count value.

[0110] In step S1572, the print controller 202 acquires the temperature and humidity of the environment in which the recording apparatus 1 is installed.

[0111] In step S1573, the print controller 202 derives an evaporation rate coefficient corresponding to the temperature and humidity acquired in step S1572. A method for deriving this evaporation rate coefficient will be described in detail below.

[0112] First, similarly to the second embodiment, the temperature and humidity conditions of the installation environment are classified using a graph such as the example shown in FIG. 14(b) based on the temperature and humidity acquired in step S1572.

[0113] Next, an evaporation rate coefficient corresponding to the temperature and humidity conditions classified above is derived by referring to a table such as the example shown in Figure 15(c). As shown in Figure 15(c), the more easily the ink is concentrated in a state, the larger the evaporation rate coefficient. However, since the cap closed state is a state in which ink evaporation is less likely to progress than the cap open state, the evaporation rate coefficient values ​​stored in the table of Figure 15(c) are generally smaller than the evaporation rate coefficient values ​​stored in the table of Figure 14(c). Note that the table shown in Figure 15(c) is merely an example, and other tables may be used.

[0114] In step S1574, the print controller 202 obtains the capping time.

[0115] In step S1575, the print controller 202 multiplies the evaporation rate coefficient derived in step S1573 by the capping time acquired in step S1574, and then adds the value obtained by this multiplication to the current in-cap evaporation rate count value acquired in step S1571.

[0116] In step S1576, the print controller 202 updates the in-cap evaporation rate count value, specifically, overwrites the in-cap evaporation rate count value stored in the ROM 203 with the value calculated in step S1575 and saves it.

[0117] The processes in steps S1577 to S1579 are similar to the processes in steps S1327 to S1329. The above is the content of the process of adding the evaporation rate in the cap while the cap is closed in this embodiment.

[0118] <Effects of this embodiment> In this embodiment, the evaporation rate in the cap is counted taking into consideration the evaporation of ink in the cap closed state as well as the evaporation of ink in the cap open state. Therefore, based on the evaporation rate in the cap derived more accurately than in the second embodiment, it is possible to circulate ink at a more appropriate frequency than in the second embodiment and keep the inside of the recording head 8 in a printable state (ensuring the ejection stability of the ejection unit 1000).

[0119] [Fourth embodiment] In this embodiment, a case will be described in which the recording apparatus 1 has a mechanism for deriving ink density information, and the ink circulation interval is changed in accordance with the density information.

[0120] <About concentration information> The density information will be described below. In this embodiment, the print controller 202 uses the ink density information (density N C (Let us say that the concentration N C The value calculated by the following formula is stored in the ROM 203, and the print controller 202 can set the density N C It is possible to obtain

[0121]

number

[0122] Here, N X+1 is the density after the recording operation, N X indicates the density before the printing operation. n is the amount of ink in the black ink circulation system before printing, I n indicates the amount of ink discharged by printing, and V indicates the amount of evaporation from the circulation system. X+1 Calculate the concentration N C The data is overwritten and saved in ROM 203.

[0123] <Method of deriving circulation intervals based on concentration information> The print controller 202 refers to a table such as that shown in FIG. C When the table shown in FIG. 16 is used, for example, when the evaporation rate count value in the cap is 200 and the concentration N C When is 0.087, the circulation interval is 13.5 hours. Note that the table in FIG. 16 is merely an example, and the relationship between the evaporation rate count in the cap and the concentration N C Other tables may be used that hold ranges of values ​​for and corresponding cycle intervals. However, such tables generally have a higher value for the larger cap evaporation count or for the concentration N C The higher the concentration N, the shorter the circulation interval. C The higher the concentration N, the more the ink is likely to thicken due to the progress of evaporation, so it is necessary to circulate the ink more frequently. C The rotation interval may be calculated using a formula in which

[0124] <Effects of this embodiment> In this embodiment, the circulation interval is derived by taking into consideration the ink concentration information as well as the evaporation rate count value in the cap. Therefore, it is possible to circulate the ink at a more appropriate frequency than in the above-mentioned embodiment and to keep the inside of the recording head 8 in a printable state (ensuring the ejection stability of the ejection unit 1000).

[0125] [Fifth embodiment] In this embodiment, a case will be described in which the time for circulating ink (referred to as circulation execution time) is changed depending on the temperature.

[0126] The print controller 202 derives the circulation execution time corresponding to the acquired temperature by referring to a table such as that shown in Fig. 17(a). Note that the temperature acquired by the print controller 202 here may be the temperature in the installation environment of the recording device 1 described above. Alternatively, if the recording device 1 has a mechanism for measuring the temperature of the recording head 8, the measured temperature of the recording head 8 may be used.

[0127] When the table shown in FIG. 17(a) is used, for example, when the temperature is 20° C., the circulation execution time is 2 minutes. Note that the table in FIG. 17(a) is merely an example, and other tables that hold temperature ranges and corresponding circulation execution time values ​​may be used. However, such tables are generally set so that the higher the temperature, the shorter the circulation execution time. This is because, as shown in FIG. 17(b), the higher the temperature, the lower the viscosity of the ink, and therefore the ejection stability of the ejection section 1000 can be restored with a short circulation execution time. Note that, although the case of using a table has been described here, instead of a table, the circulation execution time may be calculated using a formula into which the temperature value is substituted.

[0128] <Effects of this embodiment> This embodiment makes it possible to carry out the circulation for an appropriate period of time depending on the temperature.

[0129] [Sixth embodiment] In this embodiment, the recording apparatus 1 is provided with a head temperature adjustment mechanism for adjusting the temperature of the recording head 8, and the circulation execution time is changed according to the temperature setting of the temperature adjustment.

[0130] The print controller 202 derives the circulation execution time corresponding to the acquired temperature setting by referring to a table as shown in FIG. 18. The table in FIG. 18 is merely an example, and other tables that hold the temperature setting value and the corresponding circulation execution time value may be used. However, in such a table, the circulation execution time is generally set to be shorter as the temperature setting temperature is higher. This is because, as described in the fifth embodiment, the higher the temperature setting temperature is, the smaller the ink viscosity is, and therefore the ejection stability of the ejection unit 1000 can be restored with a short circulation execution time. Here, the case where a table is used has been described, but instead of the table, the circulation execution time may be calculated using a formula into which the temperature value is substituted. Also, an embodiment in which a plurality of tables as shown in FIG. 18 are stored in the ROM 203 and the tables are used differently depending on the power that can be consumed and user settings is also conceivable.

[0131] <Effects of this embodiment> This embodiment makes it possible to perform circulation for an appropriate time according to the temperature setting of the temperature control. In addition, since circulation is performed in the cap closed state in this embodiment, it is possible to suppress evaporation of water in the ink even if the target temperature of the temperature control is set to a temperature higher than that during printing.

[0132] [Seventh embodiment] In this embodiment, when the timer circulation process is repeated as in the first to third embodiments, the moisture evaporated from the ink in the ejection ports is absorbed by the absorber disposed in the cap member 10a or the ink impregnated in the absorber, etc. In this way, the inside of the cap member 10a is moistened by the absorber, etc. that has absorbed the moisture, and the progress of the evaporation of moisture from the ink in the ejection ports is suppressed. Taking this into consideration, the evaporation rate count in the cap is subtracted.

[0133] The timer circulation process in this embodiment will be described below with reference to FIG.

[0134] The processes in steps S1910 to S1960 are similar to those in steps S1510 to S1560.

[0135] In step S1970, the print controller 202 adds 1 to the timer cycle counter to update it.

[0136] In step S1980, the print controller 202 executes a timer-cycled cap evaporation rate subtraction process to subtract the fluctuation in the cap evaporation rate caused by the absorbent that has absorbed moisture from the count value of the cap evaporation rate. Details of the timer-cycled cap evaporation rate subtraction process will be described later with reference to FIG. 19(b).

[0137] The processes in steps S1990 to S2020 are similar to those in steps S1570 to S1600. In this embodiment, further in step S2030, the print controller 202 resets a timer circulation number counter.

[0138] <About the evaporation rate deduction process in the cap by timer circulation> Hereinafter, the evaporation rate subtraction process in the cap by the timer circulation (step S1980) will be described in detail with reference to FIG. 19(b).

[0139] In step S1981, the print controller 202 acquires the current in-cap evaporation rate count value, and in step S1982, the print controller 202 acquires the timer cycle count value.

[0140] In step S1983, the print controller 202 derives a subtraction value corresponding to the timer cycle counter acquired in step S1982 by referring to a table such as that shown in Fig. 19C. The method of deriving this subtraction value will be described in detail below.

[0141] When timer circulation is performed and fresh ink that has not thickened is supplied to the ejection port, the moisture content of the absorbent arranged in the cap member 10a increases by absorbing the moisture that evaporates from the ink. As a result, the inside of the cap member 10a becomes moist due to the absorbent with an increased moisture content, and the evaporation rate inside the cap becomes low.

[0142] Also, experimental results show that the lower the number of timer cycles, the higher the humidifying effect inside the cap per timer cycle. Therefore, as shown in Figure 19(c), the lower the number of timer cycles, the larger the subtraction value to be subtracted from the evaporation rate count value inside the cap. As the number of timer cycles increases, the moisture inside the cap and the absorbent becomes saturated, and the humidifying effect inside the cap due to the evaporation of moisture from the nozzle is almost eliminated. Therefore, if the number of timer cycles exceeds 32, the subtraction value is set to 0.

[0143] In step S1984, the print controller 202 updates the in-cap evaporation rate count value based on the acquired subtraction value. Specifically, the print controller 202 overwrites and saves the in-cap evaporation rate count value stored in the ROM 203 with a value obtained by subtracting the subtraction value from the in-cap evaporation rate count value.

[0144] <Effects of this embodiment> In this embodiment, the evaporation rate in the cap is counted taking into consideration the humidifying effect inside the cap due to timer circulation. Therefore, based on the evaporation rate in the cap derived more accurately than in the third embodiment, ink is circulated at a more appropriate frequency than in the third embodiment, making it possible to keep the inside of the recording head 8 in a printable state (ensuring the ejection stability of the ejection unit 1000).

[0145] [Other embodiments] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a 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 implements one or more of the functions. [Explanation of symbols]

[0146] 8. Recording Head 8a Discharge port surface 10 Cap Units 209 Ink supply control unit

Claims

1. a recording head including: an ejection port surface provided with ejection ports for ejecting liquid; recording elements for generating energy for ejecting liquid from the ejection ports; pressure chambers provided between the recording elements and the ejection ports; a first flow path communicating with the pressure chambers; and a second flow path communicating with the pressure chambers, wherein liquid is ejected from the ejection ports through the pressure chambers; a capping mechanism for capping the ejection port surface; A circulation means for circulating the liquid; having A recording device characterized in that, when the time during which the discharge port surface is capped by the capping mechanism exceeds a predetermined time, the circulation means circulates liquid from the first flow path through the pressure chamber to the second flow path without being discharged from the discharge port.

2. 2. The recording apparatus according to claim 1, further comprising a calculation unit that calculates a time for which the circulation unit performs circulation based on a temperature in an environment in which the recording apparatus is installed or a temperature of the recording head.

3. a head temperature control mechanism for controlling the temperature of the recording head; 3. The recording apparatus according to claim 1, further comprising: a calculation unit that calculates a time for which the circulation unit performs circulation based on a set temperature of the head temperature adjustment mechanism.

4. A tank for storing liquid; a supply flow path for supplying liquid from the tank to the recording head; a recovery flow path that recovers liquid from the recording head to the tank; having 4. The recording apparatus according to claim 1, wherein the circulation means circulates liquid from the tank through the supply flow path, the first flow path, the pressure chamber, the second flow path, and the recovery flow path to the tank.

5. 5. The recording apparatus according to claim 4, wherein the circulation means comprises a supply pump provided in the supply flow path and a recovery pump provided in the recovery flow path.

6. A tank for storing liquid; a supply flow path for supplying liquid from the tank to the recording head; having 4. The recording apparatus according to claim 1, wherein the circulation means is a pump provided in the supply flow path.

7. 7. The recording apparatus according to claim 4, further comprising a main tank for storing liquid to be supplied to said tank.

8. A tank for storing liquid; a supply flow path for supplying liquid from the tank to the recording head; A negative pressure control unit that generates a negative pressure, 8. The recording apparatus according to claim 1, wherein the negative pressure control unit is provided between the supply flow path and the ejection port.

9. A tank for storing liquid; a supply flow path for supplying liquid from the tank to a recording head; A negative pressure control unit that generates a negative pressure, 8. The recording apparatus according to claim 1, wherein the negative pressure control unit is provided between the tank and the ejection port.

10. A filter is provided.

10. The recording apparatus according to claim 9, wherein the filter is provided upstream of the negative pressure control unit in a direction of ink flow from the tank to the recording head.

11. 11. The recording apparatus according to claim 1, wherein the recording head has a negative pressure control unit that generates a negative pressure.

12. The recording head has two negative pressure control units, 12. The recording apparatus according to claim 11, wherein the two negative pressure control units generate different negative pressures.

13. A recording apparatus as claimed in any one of claims 1 to 12, characterized in that the recording head is a full-line head.

14. Having an acquisition means for acquiring information regarding a time when liquid is not being ejected from the ejection port, The recording device according to claim 1, characterized in that when the time indicated by the information acquired by the acquisition means exceeds the predetermined time, the circulation means circulates liquid from the first flow path through the pressure chamber to the second flow path while the ejection outlet surface is capped by the capping mechanism.

15. a recording head including: an ejection port surface provided with ejection ports for ejecting liquid; recording elements for generating energy for ejecting liquid from the ejection ports; pressure chambers provided between the recording elements and the ejection ports; a first flow path communicating with the pressure chambers; and a second flow path communicating with the pressure chambers, wherein liquid is ejected from the ejection ports through the pressure chambers; a capping mechanism for capping the ejection port surface; A circulation means for circulating the liquid; A method for controlling a recording device comprising: A control method characterized in that, when the time during which the discharge port surface is capped by the capping mechanism exceeds a predetermined time, the circulation means circulates liquid from the first flow path through the pressure chamber to the second flow path without being discharged from the discharge port.

16. 16. The method according to claim 15, further comprising a deriving step of deriving a time for performing circulation in the circulation step, based on a temperature in an installation environment of the printing apparatus or a temperature of the printhead.

17. A program for causing a computer to execute the method according to claim 15 or 16.

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