JP7423259B2 - Inkjet recording device, control device, and program - Google Patents

Description

The present invention relates to an inkjet printing apparatus that performs recovery processing to maintain and restore a good state of ink ejection from a printhead, a control device that controls the inkjet printing apparatus, and a program.

In an inkjet recording device, ink within a nozzle that ejects ink becomes thicker over time, which causes ejection failure due to nozzle clogging, landing misalignment, and the like. Patent Document 1 discloses a technique for eliminating ejection failure caused by such thickened ink.

JP2011-62847A

However, in Patent Document 1, the ink ejection state from the nozzle is detected, and if it is not detected that the ink ejection state is good, a recovery operation is performed to recover the ink ejection state, and then , the ink ejection state is detected again. Therefore, the recovery process, which is a series of processes of detecting the ink ejection state, performing a recovery operation, and detecting that the ink ejection state is good, takes time.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique that can shorten the time required for recovery processing.

In order to achieve the above object, the present invention includes: a recording device including a plurality of nozzles that eject ink using heat generated by a recording element; a circulation device capable of circulating ink in a circulation path including the recording device; An inkjet recording apparatus comprising: a detection means for detecting an ink ejection state in a nozzle based on a detected temperature of the nozzle when ink is ejected; control means for controlling the recording element to generate heat to eject ink from the nozzle without circulating the ink by the circulation means, and for the detection means to detect the state of ink ejection from the nozzle during a recovery process; , determining means for determining whether the ink ejection state in the recording means is good or bad based on the number of first nozzles for which ink is not normally ejected by the detection means, The means includes a plurality of chips in which nozzles for ejecting ink are arranged, and the determining means determines the ink ejection state in each of the chips, and determines the ink ejection state in the recording means based on the determination. and the determining means determines the ink ejection state in the chip based on a threshold value depending on the position where the chip is arranged, and the threshold value is set low in the center part in the arrangement direction of the chip. , is set high on the end side in the arrangement direction, and the control means repeats the detection by the detection means until the determination means determines that the ink ejection state in the recording means is good. shall be.

According to the present invention, it is possible to shorten the time required for recovery processing.

FIG. 3 is a diagram when the recording device is in a standby state. FIG. 3 is a control configuration diagram of the recording device. FIG. 3 is a diagram when the recording device is in a recording state. FIG. 3 is a transport route diagram of a recording medium fed from a first cassette. FIG. 3 is a diagram when the recording device is in a maintenance state. FIG. 2 is a perspective view showing the configuration of a maintenance unit. FIG. 2 is a schematic configuration diagram of an ink supply system. FIG. 3 is a diagram illustrating the flow of ink in a flow path including an ejection port. FIG. 3 is a configuration diagram of the vicinity of the ejection ports of the recording element substrate. FIG. 3 is a diagram illustrating a temperature detected by a temperature detection element. FIG. 3 is a diagram illustrating the removal of concentrated ink by ink circulation and ejection. 3 is a flowchart of recording processing and recovery processing performed by the recording apparatus of the first embodiment. It is a table showing threshold values used in the first determination method. It is a table showing threshold values used in a second determination method. It is a figure explaining the 3rd determination method. 12 is a flowchart of recovery processing performed by the recording apparatus according to the second embodiment. 12 is a flowchart of recovery processing performed by the recording apparatus according to the third embodiment. 12 is a flowchart of recovery processing performed by the recording apparatus according to the fourth embodiment. 12 is a flowchart of recovery processing performed by the recording apparatus according to the fifth embodiment.

Embodiments of the present invention will be described in detail below with reference to the drawings. The following embodiments do not limit the present invention, and not all combinations of features described in the embodiments are essential to the solution of the present invention. Note that the relative arrangement, shape, etc. of the components described in the embodiments are merely examples, and are not intended to limit the scope of the present invention to only these. In the following embodiments, an inkjet recording apparatus will be described as an example of a liquid ejection apparatus including a liquid ejection head that ejects droplets.

(First embodiment)
First, an inkjet recording apparatus according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 15. FIG. 1 is an internal configuration diagram of an inkjet printing apparatus 1 (hereinafter referred to as printing apparatus 1) used in this embodiment. In the figure, the x direction is a horizontal direction, the y direction (perpendicular to the paper surface) is a direction in which ejection ports are arranged in a recording head 8, which will be described later, and the z direction is a vertical direction.

The recording device 1 is a multifunctional device that includes a print section 2 and a scanner section 3, and the print section 2 and the scanner section 3 can perform various processes related to recording operations and reading operations individually or in conjunction with each other. The scanner section 3 is equipped with an ADF (Auto Document Feeder) and an FBS (Flatbed Scanner), and is capable of reading originals automatically fed by the ADF and reading (scanning) originals placed on the original table of the FBS by the user. )It can be performed. Note that although this embodiment is a multifunctional device that has both a print section 2 and a scanner section 3, it may be a multifunction device that does not include the scanner section 3. FIG. 1 shows a state in which the recording apparatus 1 is in a standby state in which neither recording nor reading operations are performed.

In the print section 2, a first cassette 5A and a second cassette 5B for accommodating a recording medium (cut sheet) S are removably installed at the bottom of the housing 4 in the vertical direction. The first cassette 5A stores relatively small recording media up to A4 size, and the second cassette 5B stores relatively large recording media up to A3 size in a flat stack. A first feeding unit 6A is provided near the first cassette 5A to separate and feed the stored 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 medium S is selectively fed from one of the cassettes.

The conveyance roller 7, the discharge roller 12, the pinch roller 7a, the spur 7b, the guide 18, the inner guide 19, and the flapper 11 are a conveyance mechanism for guiding the recording medium S in a predetermined direction. The conveyance roller 7 is a drive roller that is disposed upstream and downstream of the recording head 8 and driven by a conveyance motor (not shown). The pinch roller 7a is a driven roller that rotates together with the conveyance roller 7 while nipping the recording medium S. The discharge roller 12 is a drive roller arranged downstream of the conveyance roller 7 and driven by a conveyance motor (not shown). The spur 7b, together with the conveyance roller 7 and discharge roller 12 arranged on the downstream side of the recording head 8, nip and convey the recording medium S.

The guide 18 is provided on the conveyance 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 and has a curved side surface, and guides the recording medium S along the side surface. The flapper 11 is a member for switching the direction in which the recording medium S is conveyed during a 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.

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

The ink tank unit 14 stores four colors of ink to be supplied to the recording head 8. The ink supply unit 15 is provided in the middle of a flow path connecting the ink tank unit 14 and the recording head 8, and adjusts the pressure and flow rate of ink within the recording head 8 to an appropriate range. In this embodiment, a circulating ink supply system is employed, and the ink supply unit 15 adjusts the pressure of ink supplied to the recording head 8 and the flow rate of ink recovered from the recording head 8 within an appropriate range.

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

FIG. 2 is a block diagram showing a control configuration in the recording apparatus 1. As shown in FIG. The control configuration mainly includes a print engine unit 200 that controls the print section 2, a scanner engine unit 300 that controls the scanner section 3, and a controller unit 100 that controls the entire recording apparatus 1. The print controller 202 controls various mechanisms of the print engine unit 200 according to instructions from the main controller 101 of the controller unit 100. Various mechanisms of the scanner engine unit 300 are controlled by a main controller 101 of the controller unit 100. The details of the control configuration will be explained below.

In the controller unit 100, a main controller 101 composed of a CPU controls the entire recording apparatus 1, using the RAM 106 as a work area, according to programs and various parameters stored in the ROM 107. For example, when a print job is input from the host device 400 via the host I/F 102 or the wireless I/F 103, the image processing unit 108 performs predetermined image processing on the received image data according to instructions from the main controller 101. give Then, the main controller 101 transmits the image data subjected to image processing to the print engine unit 200 via the print engine I/F 105.

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

The operation panel 104 is a mechanism by which the user performs input/output to the recording apparatus 1 . The user can instruct operations such as copying and scanning, set a print mode, and recognize information on the recording device 1 via the operation panel 104.

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

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

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 programs and various parameters stored in the ROM 107. Thereby, various mechanisms included in the scanner section 3 are controlled. For example, the main controller 101 controls the hardware resources in the scanner controller 302 via the controller I/F 301, so that the document loaded on the ADF by the user is transported via the transport control unit 304 and read by the sensor 305. . Then, the scanner controller 302 stores the read image data in the RAM 303. Note that the print controller 202 can cause the print head 8 to perform a printing operation based on the image data read by the scanner controller 302 by converting the image data acquired as described above into print data. .

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 separated from the ejection port surface 8a of the recording head 8, and the ejection port surface 8a faces the platen 9. In this embodiment, the plane of the platen 9 is inclined at approximately 45 degrees with respect to the horizontal direction, and the ejection port surface 8a of the print head 8 at the print position is also aligned in the horizontal direction so that the distance from the platen 9 is maintained constant. It is tilted at approximately 45 degrees.

When moving the recording head 8 from the standby position shown in FIG. 1 to the recording position shown in FIG. 3, the print controller 202 lowers the cap unit 10 to the retracted position shown in FIG. 3 using the maintenance control section 210. As a result, the ejection port surface 8a of the recording head 8 is separated from the cap member 10a. Thereafter, the print controller 202 rotates the print head 8 by 45 degrees while adjusting the vertical height of the print head 8 using the head carriage control unit 208, 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 reverse process to the above.

Next, the conveyance path of the recording medium S in the print section 2 will be explained. When a print command is input, the print controller 202 first moves the print head 8 to the print position shown in FIG. 3 using the maintenance control section 210 and the head carriage control section 208. Thereafter, the print controller 202 uses the conveyance control unit 207 to drive either the first feeding unit 6A or the second feeding unit 6B according to the recording command to feed the recording medium S.

FIGS. 4(a) to 4(c) are diagrams showing the conveyance path when the A4 size recording medium S accommodated in the first cassette 5A is fed. The recording medium S stacked at the top in the first cassette 5A is separated from the second and subsequent recording media by the first feeding unit 6A, and is nipped between the conveyance roller 7 and the pinch roller 7a while being held at the platen 9. and the recording head 8 toward the recording area P. FIG. 4A shows the conveyance state immediately 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 tilted at approximately 45 degrees with respect to the horizontal direction while being fed to the first feeding unit 6A and reaching the recording area P. Ru.

In the recording area P, ink is discharged toward the recording medium S from a plurality of discharge ports provided in the recording head 8 . The back surface of the recording medium S in the area to which ink is applied is supported by the platen 9, and the distance between the ejection port surface 8a and the recording medium S is kept constant. After the ink has been applied, the recording medium S passes along the left side of the flapper 11 whose tip is tilted to the right, guided by the conveyance roller 7 and the spur 7b, and moves upward in the vertical direction of the recording apparatus 1 along the guide 18. transported. FIG. 4B shows a state in which the leading edge of the recording medium S passes through the recording area P and is conveyed vertically upward. The traveling direction of the recording medium S is changed from the position of the recording area P inclined at about 45 degrees with respect to the horizontal direction to the vertical direction upward by the conveyance roller 7 and the spur 7b.

After the recording medium S is conveyed vertically upward, it is discharged onto the discharge tray 13 by the discharge roller 12 and the spur 7b. FIG. 4C shows a state in which the leading edge of the recording medium S passes through the discharge roller 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.

Similarly, the A3 size recording medium S accommodated in the second cassette 5B is conveyed toward the recording area P between the platen 9 and the recording head 8. That is, the recording medium S stacked on top in the second cassette 5B is separated from the second and subsequent recording media by the second feeding unit 6B, and is nipped between the conveyance roller 7 and the pinch roller 7a. The recording medium is transported toward a recording area P between the platen 9 and the recording head 8 .

Further, when double-sided recording is performed on an A4 size recording medium S, the recording operation is performed on the second side (back side) after recording on the first side (front side). The conveyance process when recording the first side is the same as that shown in FIGS. 4(a) to 4(c), so the description thereof will be omitted here. 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 reversely rotates the conveyance roller 7 to move the recording medium S inside the recording apparatus 1. Transport to. At this time, the flapper 11 is controlled by an actuator (not shown) so that its leading edge is tilted to the left, so that the leading edge of the recording medium S (the trailing edge in the recording operation of the first surface) passes through the right side of the flapper 11. It is conveyed vertically downward.

Thereafter, the recording medium S is conveyed along the curved outer circumferential surface of the inner guide 19 and again conveyed 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. The subsequent conveyance path is the same as in the case of first side recording shown in FIGS. 4(b) and 4(c). When the leading edge of the recording medium S passes through the recording area P and is conveyed vertically upward, the flapper 11 is controlled by an actuator (not shown) to move the leading edge to a position where the leading edge is tilted to the right.

Next, maintenance operations for the recording head 8 will be explained. As explained in FIG. 1, the maintenance unit 16 of this embodiment includes the cap unit 10 and the wiping unit 17, and performs maintenance operations by operating these at predetermined timing.

FIG. 5 is a diagram when the recording device 1 is 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. 5, the print controller 202 moves the recording head 8 vertically upward and also moves the cap unit 10 vertically downward. Then, the print controller 202 moves the wiping unit 17 from the retracted position to the right in FIG. Thereafter, the print controller 202 moves the recording head 8 vertically downward to a maintenance position where maintenance operations can be performed.

On the other hand, when moving the recording head 8 from the recording position shown in FIG. 3 to the maintenance position shown in FIG. 5, the print controller 202 moves the recording head 8 vertically upward while rotating it by 45 degrees. Then, the print controller 202 moves the wiping unit 17 from the retracted position to the right. Thereafter, the print controller 202 moves the recording head 8 vertically downward to a maintenance position where the maintenance unit 16 can perform maintenance operations.

FIG. 6(a) is a perspective view showing the maintenance unit 16 in the standby position, and FIG. 6(b) is a perspective view showing the maintenance unit 16 in the maintenance position. 6(a) corresponds to FIG. 1, and FIG. 6(b) corresponds to FIG. 5. When the recording head 8 is in the standby position, the maintenance unit 16 is in the standby position shown in FIG. has been done. 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 ejection port surface 8a of the recording head 8, evaporation of ink from the ejection port can be suppressed. The cap unit 10 also has a function of collecting ink ejected to the cap member 10a during preliminary ejection, etc., and causing a suction pump (not shown) to suck the collected ink.

On the other hand, in the maintenance position shown in FIG. 6(b), the cap unit 10 is moving vertically downward, and the wiping unit 17 is 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.

In the blade wiper unit 171, a blade wiper 171a for wiping the discharge port surface 8a along the x direction is arranged in the y direction by a length corresponding to the array area of the discharge 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 while being positioned at a height where the recording head 8 can come into contact with the blade wiper 171a. Due to this movement, ink and the like adhering to the ejection port surface 8a are wiped off by the blade wiper 171a.

At the entrance of the maintenance unit 16 where the blade wiper 171a is housed, a wet wiper cleaner 16a is arranged to remove ink adhering to the blade wiper 171a and apply wetting liquid to the blade wiper 171a. Each time the blade wiper 171a is stored in the maintenance unit 16, deposits are removed by the wet wiper cleaner 16a and wet liquid is applied to the blade wiper 171a. Then, when the discharge port surface 8a is wiped next time, the wet liquid is transferred to the discharge port surface 8a, thereby improving the slipperiness between the discharge port surface 8a and the blade wiper 171a.

On the other hand, the vacuum wiper unit 172 includes 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 to be able to wipe the discharge 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 operating the suction pump, ink and the like adhering to the ejection port surface 8a of the recording head 8 are wiped by the vacuum wiper 172c and sucked into the suction port. At this time, the flat plate 172a and positioning pins 172d provided at both ends of the opening are used to align the discharge port surface 8a with respect to the vacuum wiper 172c.

In this embodiment, a first wiping process in which the blade wiper unit 171 performs a wiping operation and the vacuum wiper unit 172 does not perform a wiping operation, and a second wiping process in which both wiping processes are performed in sequence can be performed. . When performing the first wiping process, the print controller 202 first pulls out the wiping unit 17 from the maintenance unit 16 with the recording head 8 retracted vertically above the maintenance position in FIG. Then, the print controller 202 moves the recording head 8 vertically downward to a position where it can come into contact with the blade wiper 171a, and then moves the wiping unit 17 into the maintenance unit 16. Due to 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 discharge port surface 8a when moving into the maintenance unit 16 from the position where it is pulled out from the maintenance unit 16.

When the blade wiper unit 171 is housed, 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 the ink collected in the cap member 10a is sucked by the suction pump.

On the other hand, when performing the second wiping process, the print controller 202 first slides the wiping unit 17 from the maintenance unit 16 with the recording head 8 retracted vertically above the maintenance position in FIG. Pull out. Then, the print controller 202 moves the recording head 8 vertically downward to a position where it can come into contact with the blade wiper 171a, and then moves the wiping unit 17 into the maintenance unit 16. Thereby, a wiping operation by the blade wiper 171a is performed on the discharge port surface 8a. Next, the print controller 202 slides the wiping unit 17 from the maintenance unit 16 and pulls it out to a predetermined position while retracting the recording head 8 vertically above the maintenance position in FIG. 5 again. Subsequently, the print controller 202 positions the ejection port surface 8a and the vacuum wiper unit 172 using the flat plate 172a and the positioning pin 172d while lowering the recording head 8 to the maintenance position shown in FIG. After that, the print controller 202 executes the wiping operation by the vacuum wiper unit 172 described above. After retracting the recording head 8 vertically upward and storing the wiping unit 17, the print controller 202 causes the cap unit 10 to perform preliminary ejection into the cap member and suction of the collected ink, similarly to the first wiping process. perform an action.

(ink supply unit)
Next, the flow path configuration of the ink circulation system of this embodiment will be explained using FIG. 7. FIG. 7 is a diagram showing a flow path configuration of an ink circulation system including the ink supply unit 15 employed in the inkjet recording apparatus 1 of this embodiment. The ink supply unit 15 supplies the ink supplied from the ink tank unit 14 to the recording head 8. Although FIG. 7 shows a configuration for one color of ink, in reality, such a configuration is prepared for each ink color. The ink supply unit 15 is basically controlled by the ink supply control section 209 shown in FIG. Each configuration of the ink supply unit 15 will be described below.

Ink mainly circulates between the sub tank 151 and the recording head 8. The recording head 8 performs an ink ejecting operation based on the image data, and the ink that is not ejected is collected into the sub tank 151 again.

The sub-tank 151 containing a predetermined amount of ink is connected to a supply channel C2 for supplying ink to the recording head 8 and a recovery channel C4 for recovering ink from the recording head 8. That is, the sub-tank 151, the supply channel C2, the recording head 8, and the recovery channel C4 constitute a circulation path in which ink circulates. Further, the sub-tank 151 is connected to a flow path C0 through which air flows.

The sub-tank 151 is provided with a liquid level detection means 151a composed of a plurality of electrode pins. The ink supply control unit 209 can grasp the height of the ink liquid level, that is, the remaining amount of ink in the sub-tank 151 by detecting the presence or absence of conduction current between the plurality of pins. The pressure reducing pump P0 is a negative pressure generation source for reducing the pressure inside the sub tank 151. The atmosphere release valve V0 is a valve for switching whether or not the inside of the sub-tank 151 is communicated with the atmosphere.

The main tank 141 is a tank that stores ink to be supplied to the sub tank 151. The main tank 141 is configured to be detachable from the main body of the recording apparatus. A tank supply valve V1 for switching the connection between the sub tank 151 and the main tank 141 is arranged in the middle of the tank connection channel C1 that connects the sub tank 151 and the main tank 141.

When the ink supply control unit 209 detects that the ink in the sub-tank 151 has become less than a predetermined amount by the liquid level detection means 151a, it closes the atmosphere release valve V0, the supply valve V2, the recovery valve V4, and the head exchange valve V5. . Further, the ink supply control unit 209 opens the tank supply valve V1. In this state, the ink supply control unit 209 operates the pressure reducing pump P0. Then, the inside of the sub-tank 151 becomes negative pressure, and ink is supplied from the main tank 141 to the sub-tank 151. When the liquid level detection means 151a detects that the ink in the sub-tank 151 exceeds a predetermined amount, the ink supply control unit 209 closes the tank supply valve V1 and stops the pressure reducing pump P0.

The supply channel C2 is a channel for supplying ink from the sub-tank 151 to the recording head 8, and a supply pump P1 and a supply valve V2 are disposed in the middle thereof. During the recording operation, by driving the supply pump P1 with the supply valve V2 open, ink can be supplied to the recording head 8 and circulated in the circulation path. The amount of ink ejected per unit time by the recording head 8 varies depending on the image data. The flow rate of the supply pump P1 is determined so as to be able to cope with the case where the recording head 8 performs an ejection operation that consumes the maximum amount of ink per unit time.

The relief flow path C3 is a flow path that is upstream of the supply valve V2 and connects the upstream side and the downstream side of the supply pump P1. A relief valve V3, which is a differential pressure valve, is disposed in the middle of the relief flow path C3. The relief valve V3 is not opened and closed by a drive mechanism, but is biased by a spring, and is configured to open when a predetermined pressure is reached. For example, the amount of ink supplied per unit time from the supply pump P1 to the IN channel 80b is the ejection amount per unit time of the recording head 8 and the amount of ink per unit time flowing from the recovery pump P2 to the recovery channel C4. Assume that the total value is greater than the total value of . In this case, the relief valve V3 is opened in response to the pressure acting on itself. Thereby, a circulating flow path is formed that includes a part of the supply flow path C2 and the relief flow path C3. By providing the configuration of the relief channel C3, the amount of ink supplied to the recording head 8 is adjusted according to the amount of ink consumed by the recording head 8, and the pressure within the circulation path can be stabilized regardless of image data. .

The recovery channel C4 is a channel for recovering ink from the recording head 8 to the sub-tank 151, and a recovery pump P2 and a recovery valve V4 are disposed in the middle thereof. The recovery pump P2 serves as a negative pressure generation source and sucks ink from the recording head 8 when circulating the ink in the circulation path. By driving the recovery pump P2, an appropriate pressure difference is generated between the IN flow path 80b and the OUT flow path 80c in the recording head 8, and the ink is circulated between the IN flow path 80b and the OUT flow path 80c. Can be done.

The recovery valve V4 is also a valve for preventing backflow when a recording operation is not being performed, that is, when ink is not being circulated in the circulation path. In the circulation path of this embodiment, the sub-tank 151 is arranged above the recording head 8 in the vertical direction (see FIG. 1). Therefore, when the supply pump P1 and the recovery pump P2 are not being driven, there is a risk that ink may flow back from the sub-tank 151 to the print head 8 due to the water head difference between the sub-tank 151 and the print head 8. In order to prevent such backflow, in this embodiment, a recovery valve V4 is provided in the recovery channel C4.

Note that the supply valve V2 also functions as a valve for preventing ink from being supplied from the sub-tank 151 to the recording head 8 when a recording operation is not being performed, that is, when ink is not being circulated in the circulation path. .

The head replacement flow path C5 is a flow path that connects the supply flow path C2 and the air chamber (space where no ink is stored) of the sub-tank 151, and a head replacement valve V5 is disposed in the middle thereof. One end of the head exchange channel C5 is connected to the upstream side of the recording head 8 in the supply channel C2 and to the downstream side of the supply valve V2. The other end of the head exchange channel C5 is connected above the sub-tank 151 and communicates with an air chamber inside the sub-tank 151. The head exchange channel C5 is used when drawing ink from the recording head 8 in use, such as when exchanging the recording head 8 or transporting the recording apparatus 1. The head exchange valve V5 is controlled by the ink supply control unit 209 to be closed except when filling the recording head 8 with ink and when collecting ink from the recording head 8.

Next, the flow path configuration within the recording head 8 will be explained. The ink supplied to the recording head 8 from the supply channel C2 passes through the filter 83, and then is supplied to the first negative pressure control unit 81 and the second negative pressure control unit 82. The control pressure of the first negative pressure control unit 81 is set to a weak negative pressure (negative pressure with a small pressure difference from atmospheric pressure), for example, -90 mmAq. The control pressure of the second negative pressure control unit 82 is set to a strong negative pressure (negative pressure with a large pressure difference from atmospheric pressure), for example, -180 mmAq. 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.

In the ink ejection section 80, a plurality of recording element substrates 80a each having a plurality of ejection ports arranged thereon are arranged, forming a long ejection port array. A common supply channel 80b (IN channel) for guiding ink supplied from the first negative pressure control unit 81 and a common recovery channel for guiding ink supplied from the second negative pressure control unit 82 80c (OUT channel) also extends in the arrangement direction of the recording element substrate 80a. Further, each recording element substrate 80a is formed with an individual supply channel connected to the common supply channel 80b and an individual recovery channel connected to the common recovery channel 80c. Therefore, in each recording element substrate 80a, ink flows such that it flows into the common supply channel 80b where the negative pressure is relatively weak and flows out into the common recovery channel 80c where the negative pressure is relatively strong. generated. A pressure chamber that communicates with each ejection port and is filled with ink is provided in the path between the individual supply flow path and the individual recovery flow path, and the flow of ink is maintained even in the ejection ports and pressure chambers that are not recording. occurs. When a discharge operation is performed on the recording element substrate 80a, a part of the ink that moves from the common supply channel 80b to the common recovery channel 80c is consumed by being discharged from the discharge ports, but the ink that was not discharged is It moves to the recovery channel C4 via the common recovery channel 80c.

FIG. 8(a) is a schematic plan view enlarging a part of the recording element substrate 80a, and FIG. 8(b) is a schematic cross-sectional view taken along the cross-sectional line VIIIb-VIIIb in FIG. 8(a). The recording element substrate 80a is provided with a pressure chamber 85 filled with ink and an ejection port 86 from which the ink is ejected. A recording element 84 is provided in the pressure chamber 85 at a position facing the ejection port 86 . Further, in the recording element substrate 80a, a plurality of individual supply channels 88 connected to the common supply channel 80b and a plurality of individual recovery channels 89 connected to the common recovery channel 80c are formed for each ejection port 86.

With the above-described configuration, in the recording element substrate 80a, a flow is generated in which ink flows into the common supply channel 80b where the negative pressure is relatively weak and flows out into the common recovery channel 80c where the negative pressure is relatively strong. . More specifically, ink flows in the order of common supply channel 80b→individual supply channel 88→pressure chamber 85→individual recovery channel 89→common recovery channel 80c. When ink is ejected by the recording element 84, a portion of the ink that moves from the common supply channel 80b to the common recovery channel 80c is ejected from the ejection port 86, thereby being discharged to the outside of the recording head 8. On the other hand, ink that has not been ejected from the ejection port 86 is collected into the recovery channel C4 via the common recovery channel 80c.

With the above configuration, when performing a recording operation, the ink supply control unit 209 closes the tank supply valve V1 and the head exchange valve V5, opens the atmosphere release valve V0, the supply valve V2, and the recovery valve V4, and supplies the ink. Drive pump P1 and recovery pump P2. As a result, a circulation path of sub-tank 151→supply channel C2→recording head 8→recovery channel C4→sub-tank 151 is established. If the amount of ink supplied per unit time from the supply pump P1 is larger than the total value of the ejection amount per unit time of the recording head 8 and the flow rate per unit time of the recovery pump P2, the relief flow path is changed from the supply flow path C2 to the relief flow path. Ink flows into C3. Thereby, the flow rate of ink flowing into the recording head 8 from the supply channel C2 is adjusted.

When a recording operation is not being performed, the ink supply control unit 209 stops the supply pump P1 and the recovery pump P2, and closes the atmospheric release valve V0, the supply valve V2, and the recovery valve V4. As a result, the flow of ink within the recording head 8 is stopped, and backflow due to the water head difference between the sub tank 151 and the recording head 8 is also suppressed. Further, by closing the atmosphere release valve V0, ink leakage from the sub-tank 151 and ink evaporation are suppressed.

When collecting ink from the recording head 8, the ink supply control unit 209 closes the atmospheric release valve V0, the tank supply valve V1, the supply valve V2, and the collection valve V4, opens the head exchange valve V5, and drives the pressure reducing pump P0. do. As a result, the inside of the sub-tank 151 becomes a negative pressure state, and the ink inside the recording head 8 is collected into the sub-tank 151 via the head exchange channel C5. In this way, the head exchange valve V5 is a valve that is closed during normal recording operation or standby, and is opened when collecting ink from the recording head 8. Note that the head exchange valve V5 is also opened when the head exchange channel C5 is filled with ink in filling the recording head 8.

Although the circulation flow path of this embodiment has a flow path configuration in which ink passes through the pressure chamber 85, it may also have a flow path configuration in which ink does not pass through the pressure chamber 85. Specifically, for example, a configuration may be adopted in which ink flows directly from the common supply channel 80b to the recovery channel C4. Note that in this embodiment, as described above, the ink supply control unit 209 and various pumps function as a circulation unit that can circulate ink in a circulation path that includes the print head 8.

(Detection of ink ejection state in nozzle)
Next, a configuration and a detection method for detecting the ink ejection state will be described. In this embodiment, the temperature detection element 91 provided on the print element substrate 80a of the print head 8 is used to detect the ink ejection state of each nozzle. That is, it is detected whether ink is normally ejected from each nozzle. The detected ink ejection state from each nozzle is used when determining the ink ejection state from the recording head 8, which will be described later. Furthermore, in the following description, a nozzle refers to a configuration provided on the recording element substrate 80a including the recording element 84, the pressure chamber 85, and the discharge port 86 for discharging ink.

FIG. 9A is a diagram showing the recording element 84 and temperature detection element 91 provided on the recording element substrate 80a. 9(b) is a sectional view taken along the line IXb-IXb in FIG. 9(a), and FIG. 9(c) is a sectional view taken along the line IXc-IXc in FIG. 9(a). The recording element 84 is an ejection energy generating element that generates ejection energy for ejecting ink. In this embodiment, the recording element 84 is an electrothermal conversion element (heating resistance element) made of a tantalum silicon nitride film or the like, and is connected to the wiring 93 of the recording element substrate 80a by a conductive plug 92 made of tungsten or the like. . The recording element 84 generates heat upon application of a drive pulse, thereby foaming the ink within the pressure chamber 85 . The ink in the pressure chamber 85 is ejected from the ejection port 86 using the bubbling energy. Further, in this embodiment, the temperature detection element 91 is connected to the wiring 93 by a conductive plug 98 made of a thin film resistor made of a laminated film of titanium and titanium nitride, etc., tungsten, or the like. An interlayer insulating film 94, a protective film 95, and an anti-cavitation film 96 are formed on the recording element substrate 80a. Furthermore, the recording element substrate 80a is provided with an ejection opening forming portion 97 that forms the ejection opening 86. In the recording element substrate 80a, a recording element 84 is formed on a temperature detection element 91 formed on an interlayer insulating film 94 with a protective film 95 interposed therebetween.

The temperature of the recording element 84 mounted on the recording element substrate 80a is detected by a temperature detection element 91. Then, the detected temperature is acquired using the print controller 202, the head I/F 206 connected to the print head 8, and the RAM 204. Here, the head I/F 206 includes a signal generation section 211 that generates various signals to be transmitted to the recording element substrate 80a (see FIG. 2). Also. The head I/F 206 includes an extraction section 212 that extracts a determination result signal RSLT output from a determination result output section 99 (described later) of the recording head 8 (see FIG. 2). When the print controller 202 issues an instruction to the signal generation unit for temperature detection, the signal generation unit 211 generates and outputs a signal to the recording element substrate 80a. This signal includes a clock signal CLK, a latch signal LT, a block signal BLE, a recording data signal DATA, a heat enable signal HE, and an ejection test threshold signal Ddth. The ejection test threshold signal Ddth is capable of setting a threshold value for a group of recording elements in which a plurality of recording elements mounted in the recording head 8 are divided into a plurality of groups each consisting of a plurality of recording elements located in the vicinity of each other. The configuration is such that the set value can be changed in one column cycle. In the following description, a configuration will be described in which the ejection test threshold voltage (Th) can be set for each group.

FIG. 10 is a diagram illustrating a method for determining the ink ejection state in a nozzle. FIG. 10A is a diagram showing a drive pulse P applied to the recording element 84 and a detection timing signal S for detecting temperature. FIG. 10(b) is a graph showing changes in temperature detected by the temperature detection element 91 when ink is ejected. FIG. 10(c) is a graph showing a change in temperature change value based on the temperature change in FIG. 10(b).

The recording element 84 generates heat by applying the drive pulse P shown in FIG. 10A, and ink is ejected from the ejection port 86 due to the bubbling energy of the ink. At this time, when the ink is normally ejected, the temperature detected by the temperature detection element 91 changes like a curve La shown by the solid line in FIG. When a defect occurs, it changes like a curve Lb indicated by a dotted line in FIG. 10(b). When the ink is ejected normally, a portion of the ink droplets ejected from the ejection ports 86 fall onto the top of the recording element 84 to cool the recording element 84 . As a result, the temperature in the vicinity of the recording element 84 drops rapidly, and as a result, the temperature detected by the temperature detection element 91 also drops rapidly, as shown by the curve La. On the other hand, when an ink ejection failure occurs, cooling due to some of the ink droplets falling does not occur, so the temperature detected by the temperature detection element 91 gradually decreases as shown by the curve Lb.

FIG. 10(c) is an explanatory diagram of temperature change values obtained by differentially processing the temperature changes of the curves La and Lb. When detecting the ink ejection state in the nozzle, the temperature change value at the timing set by the detection timing signal S in FIG. 10(a) is compared with a predetermined threshold Th. In FIG. 10(c), the temperature change value shown by the solid curve LA is a differential value of the curve La, and the temperature change value shown by the dotted curve LB is a differential value of the curve Lb. At the timing set by the detection timing signal S, the temperature change value of the curve LA exceeds the threshold Th, but the temperature change value of the curve LB does not exceed the threshold Th.

Here, the recording element substrate 80a provided in the recording head 8 is provided with a determination result output unit 99 that receives the detection result of the temperature detection element 91 and generates and outputs a determination result signal RSLT (FIG. reference). The determination result output unit 99 acquires a temperature change value from the detection result of the temperature detection element 91, and generates and outputs a determination result signal RSLT indicating whether or not the acquired temperature change value exceeds a threshold Th. .

Therefore, when the threshold value Th is exceeded as shown by the curve LA, the fact that the threshold value has been exceeded appears in the determination result signal RSLT. This determination result signal RSLT is extracted by the extraction unit 212, stored in the RAM 204, and used to determine whether the ink ejection state in the recording head 8 is good or bad, which will be described later. In this way, in this embodiment, the ink ejection state of each nozzle is detected depending on whether the differential value of the temperature detected by the temperature detection element 91 exceeds the threshold Th.

Note that the process of detecting the ink ejection state in the nozzles based on the detection result of the temperature detection element 91 is executed by, for example, the print controller 202. That is, in this embodiment, the recording element board 80a, the print controller 202, the head I/F 206, and the like function as a detection unit that detects the state of ink ejection from the nozzles.

The method for detecting the state of ink ejection from the nozzle is not limited to the method described above, and various known techniques can be used. Specifically, for example, a device that optically detects the ejected ink while ejecting ink from all the ejection ports of the recording head 8 optically scans the flying ink immediately after ejection. This method uses an optical scanning unit that has a light emitting section and a light receiving section. The optical scanning unit is scanned so that the optical axis formed between the light emitting part and the light receiving part passes through the flight path of the ejected ink, and when ink is being ejected, the light from the light emitting part is scanned. The light is blocked and the amount of light received by the light receiving section decreases. By detecting this decrease in the amount of received light, the state of ink ejection from the nozzle is detected.

(Removal of concentrated ink)
FIG. 11 is a schematic diagram showing a method for removing concentrated ink generated near the ejection ports, and shows the difference in removing concentrated ink by ink circulation and preliminary ejection. FIG. 11 shows that the darker the black, the higher the ink density. Concentrated ink is ink whose liquid components have evaporated and its viscosity has increased, that is, ink whose solid concentration has increased. FIGS. 11(a) to 11(c) show the case where concentrated ink is removed by ink circulation. FIG. 11(a) shows a state in which concentrated ink has formed near the ejection port, FIG. 11(b) shows a state in which the concentrated ink has begun to be removed by circulation, and FIG. 11(c) shows a state in which concentrated ink has started to be removed by circulation. It shows a steady state after a certain period of time. Furthermore, FIGS. 11(d) to (f) show cases in which concentrated ink is removed by preliminary ejection. FIG. 11(d) shows a state where concentrated ink has been generated near the ejection port, FIG. 11(e) shows a state where the concentrated ink has started to be removed by preliminary ejection, and FIG. This shows a state in which concentrated ink has been removed by preliminary ejection.

Not only during the period when the cap is open but the ink is not circulating, but also during the period when the cap is closed, the concentration of the ink is caused by evaporation of the liquid component in the ink from the surface of the ink located within the ejection port 86. proceed. Since the progress of ink concentration is basically a diffusion phenomenon, most of the concentrated components are located inside the ejection port 86 and the foaming chamber (pressure chamber 85), and the ink concentration is such that the concentrated components are distributed throughout the circulation system. is unlikely to occur.

However, when ink circulation is started in a state where ink concentration has progressed (see FIG. 11(a)), the concentrated components accumulated in the ejection port 86 and the pressure chamber 85 are moved downstream of the ink flow by the circulating ink. (see FIG. 11(b)). However, even if the circulation of the ink continues, the concentrated component continues to remain in a part of the ejection port 86 (see FIG. 11(c)), and the concentrated ink cannot be completely removed. In addition, the concentrated component mixes with the ink in the circulation system and its concentration decreases, but the concentrated component is distributed throughout the circulation system, and the concentration of ink in the entire circulation system progresses.

On the other hand, when the concentrated component is discharged from the ejection port 86 by preliminary ejection without ink being circulated, the concentrated component is discharged from the ejection port 86, so that the concentrated component remains in the ejection port 86 and is not circulated. Ink concentration in the entire system is less likely to occur.

(recording process)
In the recording device 1, when a print instruction to start printing is input, a recording process of recording on a recording medium is executed. Specifically, when a print job is input to the main controller 101 from the host device 400 or a print instruction is input from the operation panel 104, the main controller 101 causes the print controller 202 to execute recording processing. Instruct. Then, the print controller 202 executes recording processing.

FIG. 12(a) is a flowchart showing detailed processing contents of the recording process. When the printing process is started, first, circulation of ink is started (S1202). In S1202, the print controller 202 executes ink circulation in the circulation path for each ink via the ink supply control unit 209 and head I/F 206. Next, recording onto the recording medium is started (S1204). In S1204, the print controller 202 controls the head I/F 206, the conveyance control unit 207, and the head carriage control unit 208 to print on the conveyed recording medium. Thereafter, it is determined whether or not the recording on the recording medium has been completed (S1206), and if it is determined that the recording has been completed, the circulation of the ink is stopped (S1208) and the recording process is ended.

(Recovery processing)
Furthermore, in the recording apparatus 1, when the power is turned on, the ink ejection state in the recording head 8 is maintained in a good condition at a predetermined timing, such as after a print instruction is input and before recording processing is executed. Recovery processing is performed to maintain and recover. More specifically, in this embodiment, recovery processing is performed to eliminate ink ejection failure caused by ink density. Specifically, at a predetermined timing, the main controller 101 instructs the print controller 202 to execute recovery processing. Then, the print controller 202 executes recovery processing. As described above, in this embodiment, the main controller 101 and the print controller 202 function as a control unit or a control device that controls execution of recovery processing.

FIG. 12(b) is a flowchart showing detailed processing contents of the recovery processing. In this recovery process, ink circulation is not performed. In addition, in order to determine the timing to end the recovery process, the detection result of the above-described detection process for detecting the ink ejection state in the nozzle is used. Note that such recovery processing is executed for each ink color. When the recovery process is started, first, a detection process that involves an ink ejection operation is executed (S1210). That is, the ink ejection state of each nozzle is detected by the above-described detection process. Next, based on the detection result in this detection process, it is determined whether the ink ejection state in the recording head 8 is good (S1212). A specific determination method for determining whether or not the ink ejection state of the recording head 8 is good based on the detection result will be described later. The basic idea of this determination method is that, for example, if the number of non-ejecting nozzles is less than or equal to a first number determined by a predetermined condition, it is determined that the ink ejection condition in the recording head 8 is good. be done. On the other hand, if the number of non-ejecting nozzles is greater than the first number, it is determined that the ink ejection condition in the recording head 8 is not good.

If it is determined in S1212 that the condition is not good, the process returns to S1210 and the detection process is executed again. Furthermore, if it is determined in S1212 that the condition is good, the recovery process ends. In this way, in this recovery process, the detection process and the determination based on the detection result of the detection process are repeatedly executed until it is determined that the ink ejection state of the recording head 8 is good.

Here, an explanation will be given of the effect when the detection process is continued in a state where the ejection port is blocked by concentrated ink. If the concentrated ink blocks the ejection port and the ink cannot be ejected, the ejection failure will continue for some time after the detection operation starts due to the increased viscosity of the ink near the ejection port. The change in the detected temperature at this time is such that the detected temperature gradually decreases as shown by the curve Lb in FIG. 10(b).

When the ejection operation based on the detection process is repeatedly performed, ink is gradually ejected, and thereafter, the amount of ink ejected gradually increases. This is because as the ink is ejected, the thickening of the ink in the vicinity of the ejection port is gradually eliminated, and as a result, the ink becomes easier to be ejected from the ejection port. When the thickening of the ink near the ejection port is resolved, that is, when the removal of the concentrated ink near the ejection port is completed, the detected temperature changes rapidly, as shown by curve La in FIG. 10(b). It becomes like this.

As a result, the ink is ejected without circulating the ink, so that the concentrated component (concentrated ink) near the ejection port does not flow downstream. Further, by continuing the detection operation until the ink ejection condition of the recording head 8 becomes good, it becomes possible to reliably remove the concentrated ink from within the recording head.

In the recovery process described above, a process for maintaining and recovering the ink ejection state in the recording head 8 is performed while a detection process that involves ink ejection is performed as a process for detecting the ink ejection state in each nozzle. There is. Therefore, in each nozzle, while the ink ejection state is detected, processing is performed to maintain and restore the ink ejection state to a favorable state. Therefore, the time required for the recovery process is relatively short. In other words, the time required for the recovery process is shorter than the known technique in which the process of detecting the ink ejection state and the process of maintaining and recovering the ink ejection state are performed in sequence.

(Method of determining ink ejection state in recording head 8)
In the above-mentioned recovery process, as a judgment method for judging whether or not the ink ejection state of the recording head 8 is good, for example, the following three judgment methods are used: a first judgment method, a second judgment method, and a third judgment method. A determination method can be used.

<First determination method>
In the first determination method, the quality of the ink ejection state of the entire recording head 8 is determined based on the number of nozzles that are no longer able to eject ink normally, that is, have failed to eject ink. For example, as the recording head 8, 15 chips corresponding to the recording element substrate 80a are arranged in series, and each chip has 1024 nozzles for each ink color that can eject five colors of ink. Assume the head. The five color inks are black (K1, K2), cyan (C), magenta (M), and yellow (Y). Note that each nozzle includes a recording element 84, a pressure chamber 85, and an ejection port 86. The total number of nozzles in this recording head 8 is 76,800 (5×1024×15).

FIG. 13 is a table in which the threshold values used in the first determination method are set for each ink color, (a) is a table in which the number of non-ejecting nozzles (first nozzles) is used as a threshold, and (b) is a table in which the threshold values are set for each ink color. It is a table in which the percentage of non-ejecting nozzles is set as a threshold value. Note that the threshold values shown in FIGS. 13A and 13B are merely examples, and can be changed as appropriate depending on the configuration of the recording head 8 and the like. Moreover, such a threshold value can be determined experimentally, for example.

In the first determination method, as shown in FIG. 13A, the number of non-ejecting nozzles in which ink ejection failure has occurred is preset as a threshold value for each ink color. For each ink color, the number of non-ejecting nozzles detected in the detection process is compared with the corresponding threshold value. When the number of detected non-ejecting nozzles for all ink colors is equal to or less than the corresponding threshold value, it is determined that the ejection state of the nozzles in the recording head 8 is good. On the other hand, when the number of detected non-ejecting nozzles for at least one ink color exceeds the corresponding threshold value, it is determined that the ejection state of the nozzles in the recording head 8 is not good.

Further, the threshold value is set not only for each ink color but also for the total of all ink colors. Even if each ink color is below the threshold value, if the total number of all ink colors of the nozzles determined to be non-ejecting nozzles exceeds the threshold value, the print controller 202 determines that the ejection state of the nozzles in the print head 8 is good. It is determined that it is not. On the other hand, when the total number is less than or equal to the threshold value, the print controller 202 determines that the ejection state of the nozzles in the recording head 8 is good.

Note that with black ink, when a nozzle ejection failure occurs, changes in the recorded image due to the ejection failure are likely to be noticeable. For this reason, it is preferable to set the corresponding threshold value relatively small for black ink. In addition, with yellow ink, when a nozzle ejection failure occurs, changes in the recorded image due to the ejection failure are less noticeable. Therefore, for yellow ink, the corresponding threshold value can be set relatively large.

Further, in the first determination method, as shown in FIG. 13(b), the ratio of the number of non-ejecting nozzles to the total number of nozzles for each ink color may be set in advance as a threshold value for each ink color. In this case, when the proportion of detected non-ejecting nozzles for all ink colors is equal to or less than the corresponding threshold value, it is determined that the ejection state of the nozzles in the recording head 8 is good. On the other hand, when the proportion of detected non-ejecting nozzles for at least one ink color exceeds the corresponding threshold value, it is determined that the ejection state of the nozzles in the recording head 8 is not good.

Note that in this case as well, the ratio of the total number of nozzles determined to be non-ejecting nozzles for all ink colors to the total number of nozzles is also set as a threshold value. Even if the value is below the threshold value in each ink process, if the ratio of the total number of all ink colors of the nozzles determined to be non-ejecting nozzles exceeds the threshold value, the print controller 202 causes the print head 8 to eject the nozzles. It is determined that the condition is not good. On the other hand, when the ratio is less than or equal to the threshold, the print controller 202 determines that the ejection state of the nozzles in the recording head 8 is good.

<Second determination method>
In the second determination method, the quality of the ejection state of the nozzles of the entire print head 8 is determined based on the number of non-ejection nozzles in each chip (print element substrate 80a) in the print head 8. As in the case of the first determination method described above, the recording head 8 has 15 chips corresponding to the recording element substrate 80a arranged in series, and the nozzles capable of ejecting ink of five colors to each chip determine the ink color. Assume that 1024 recording heads are formed for each recording head.

FIG. 14 is a table in which the threshold values used in the second determination method are set for each chip. 3 is a table in which the number of non-ejecting nozzles set for each ink color is set as a threshold value. Note that the threshold values shown in FIGS. 14A and 14B are merely examples, and can be changed as appropriate depending on the configuration of the recording head 8 and the like. Moreover, such a threshold value can be determined experimentally, for example.

In the second determination method, as shown in FIG. 14(a), the total number of non-ejecting nozzles that occur for each of the five color inks is preset as a threshold value for each of the 15 chips from 0th to 14th. I'll keep it. Then, for each chip, the total number of detected non-ejecting nozzles for each of the five colors of ink is compared with the corresponding threshold value. When the total number of detected ejection failure nozzles in all chips is equal to or less than the corresponding threshold value, it is determined that the ejection state of the nozzles in the recording head 8 is good. On the other hand, when the total number of detected ejection failure nozzles in at least one chip exceeds the corresponding threshold value, it is determined that the ejection state of the nozzles in the recording head 8 is not good. Note that for chips located at the center in the arrangement direction, changes in the recorded image are likely to be noticeable when nozzle discharge failure occurs, so it is preferable to set the corresponding threshold value relatively small. Further, in the chips located at both ends in the array direction, changes in the recorded image are less noticeable when nozzle discharge failure occurs, so the corresponding threshold value can be set relatively large.

Furthermore, in the second determination method, as shown in FIG. 14(b), the number of non-ejecting nozzles may be set as a threshold value for each ink color in each chip. In this case, when the number of ejection failure nozzles detected for each ink color in all chips is equal to or less than the corresponding threshold value, it is determined that the ejection state of the nozzles in the recording head 8 is good. When at least one of the number of non-ejecting nozzles detected for each ink color exceeds the corresponding threshold value in at least one chip, it is determined that the ejection state of the nozzles in the recording head 8 is not good.

Note that in the second determination method, the determination was made based on the number of non-discharging nozzles, but as in the first determination method, the determination was made based on the ratio of the number of non-discharging nozzles to the total number of nozzles for each ink color. You may also do so.

<Third determination method>
In the third determination method, nozzles stored in advance as non-ejecting nozzles are excluded, and the quality of the ejection state of the nozzles of the entire recording head 8 is determined based on the number of newly detected non-ejecting nozzles.

The main cause of the ink ejection failure state, which can be recovered by ink circulation and preliminary ejection, is the adhesion of concentrated ink to ejection ports and the like. However, for nozzles that have been determined to be non-ejecting nozzles in the previously executed detection process (hereinafter referred to as "non-ejecting determined nozzles"), depending on the factors, ink circulation, preliminary ejection, etc. There is a possibility that the discharge state cannot be recovered satisfactorily. Note that the above-mentioned factors include, for example, nozzle failure and clogging of the ejection port due to foreign matter such as dust.

In the third determination method, a non-discharge determination nozzle (second nozzle) whose ink discharge state cannot be recovered by only ink circulation or preliminary discharge is memorized, and these non-discharge determination nozzles are used to determine whether the ink of the entire recording head 8 is Exclude from the target for determining whether the discharge condition is good or bad. Thereby, the time during which recording cannot be performed can be shortened by the recovery process. The controller unit 100 or the print engine unit 200 has a function for storing in the ROM 107 non-ejecting nozzles that cannot be recovered by ink circulation and preliminary ejection.

FIG. 15 is a diagram for explaining a specific example of the third determination method. In FIG. 15, for ease of understanding, the number of nozzles for each ink color is assumed to be 10 (nozzle numbers 0 to 9). Further, the threshold value for each ink color is set to 15% as the ratio of the number of non-ejecting nozzles to the total number of nozzles for each ink color.

Assume that the detection process yields a detection result as shown in FIG. 15. In this detection result, regarding the nozzles that eject the black ink K1, two nozzles with nozzle numbers "2" and "6" are detected as non-ejecting nozzles. Note that the nozzle number "2" is stored in advance as a nozzle for which no ejection has been determined. Therefore, in the determination based on this detection result, the number of nozzles to be determined is 9, which is the total number of nozzles, 10, minus the number of nozzles for ejection failure determination, which is 1. Further, the number of non-discharging nozzles to be determined is one obtained by subtracting the number of non-discharging nozzles (one) from the number of actually detected non-discharging nozzles (two). As a result, the proportion of non-ejecting nozzles becomes 11%, which is less than the corresponding threshold value of 15%. As a result, it is determined that the ink ejection condition of the nozzle that ejects the black ink K1 is good. Note that the ink ejection conditions of the nozzles that eject cyan ink C, magenta ink M, and yellow ink Y, respectively, are also determined to be good.

Regarding the nozzles that eject black ink K2, nozzle number "4" is stored as a non-ejection determination nozzle, but in this detection result, two nozzles with nozzle numbers "8" and "9" are It has been detected as a non-ejecting nozzle. Therefore, the number of nozzles to be determined is nine, and the number of ejection failure nozzles to be determined is two. As a result, the proportion of non-ejecting nozzles becomes 22%, which exceeds the corresponding threshold of 15%. As a result, it is determined that the ink ejection condition of the nozzle that ejects the black ink K2 is not good.

In this way, the quality of the ink ejection state is determined for each ink color, and if the detection result as shown in FIG. It is determined that the ink ejection condition in the head 8 is not good. Further, if it is determined that the ink ejection condition is good in the nozzles of all ink colors, it is determined that the ink ejection condition in the recording head 8 is good.

As described above, in the recording apparatus 1 according to the first embodiment, the ink ejection state is detected based on the temperature change when ink is ejected from the nozzles. In the recovery process for maintaining and restoring the ink ejection condition in the recording head 8, the ink ejection operation performed by the detection process that detects the ink ejection condition of the nozzle causes concentration, which can be a cause of ink ejection failure. Now removes ink.

As a result, in the printing apparatus 1, a detection process for detecting the ink ejection state of the nozzles and a recovery operation for restoring the ink ejection state of the print head 8 are executed in parallel. Therefore, the time it takes to detect the discharge state of the nozzle, perform the recovery operation, and determine that the discharge state of the nozzle is good, that is, the time required for the recovery process can be shortened.

(Second embodiment)
Next, an inkjet recording apparatus according to a second embodiment of the present invention will be described with reference to FIGS. 16(a) and 16(b). In the following description, the same reference numerals as those used in the first embodiment are used for the same or corresponding configurations as those in the first embodiment described above, and detailed explanation thereof will be omitted.

The second embodiment differs from the first embodiment described above in that in the recovery process, execution of the detection process is stopped at a predetermined timing and the recovery process is ended.

FIG. 16 is a flowchart showing detailed processing contents of the recovery processing executed by the recording apparatus according to the second embodiment. FIG. 16(a) is a flowchart when a predetermined timing is set based on the elapsed time after starting the recovery process. FIG. 16(b) is a flowchart when a predetermined timing is set based on the number of detection processes.

When the recovery process is started, first, time counting is started (S1602). That is, in S1602, the print controller 202 starts counting time using a counter (not shown) provided in the print engine unit 200. Next, a detection process for detecting the ink ejection state in the nozzle is executed (S1604). Thereafter, based on the detection result of this detection process, it is determined whether the ink ejection state of the recording head 8 is good (S1606). The specific processing contents of S1604 and S1606 are the same as those of S1210 and S1212 described above, so a description thereof will be omitted.

If it is determined in S1606 that the condition is good, this recovery process ends. If it is determined in S1606 that the condition is not good, it is determined whether a predetermined time has elapsed since the start of the recovery process (S1608). If it is determined in S1608 that the predetermined time has not elapsed, the process returns to S1604 and the detection process is executed again. Further, if it is determined in S1608 that the predetermined time has elapsed, this recovery processing is ended.

Further, the predetermined timing for ending the recovery process is not limited to the elapsed time from the start of the recovery process. That is, the predetermined timing may be determined based on the number of times the detection process has been performed. Specifically, when the recovery process is started, the print controller 202 first sets a variable n representing the number of detections to "1" (S1610). Next, a detection process for detecting the ink ejection state in the nozzle is executed (S1612). Thereafter, it is determined whether the ink ejection state of the recording head 8 is good or not based on the detection result of the detection process (S1614). The specific processing contents of S1610 and S1614 are the same as those of S1210 and S1212 described above, so a description thereof will be omitted.

If it is determined in S1614 that the condition is good, this recovery process ends. Further, if it is determined in S1614 that the condition is not good, it is determined whether the variable n has reached a predetermined value (S1616). If it is determined in S1616 that the predetermined value has not been reached, the variable n is incremented (S1618), and the process returns to S1612 to execute the detection process again. Further, if it is determined in S1616 that the predetermined value has been reached, this recovery process is ended.

In the second embodiment, when the recovery process ends at a predetermined timing, for example, a notification may be made to the effect that the ink ejection state of the print head 8 has not been improved.

As described above, in the recording apparatus 1 according to the second embodiment, the recovery process is ended at a predetermined timing after the start of the recovery process. As a result, in addition to the effects of the first embodiment, the printing apparatus 1 can prevent the ink ejection state of the print head 8 from being recovered by preliminary ejection or ink circulation due to a failure of the printing element 84, for example. , the recovery process can be finished.

(Third embodiment)
Next, an inkjet recording apparatus according to a third embodiment of the present invention will be described with reference to FIGS. 17(a) and 17(b). In the following description, the same reference numerals as those used in the first embodiment are used for the same or corresponding configurations as those in the first embodiment described above, and detailed explanation thereof will be omitted.

The third embodiment differs from the first and second embodiments described above in the following points. That is, in the recovery process, if it continues to be determined that the ink ejection state of the recording head 8 is not good based on the detection result of the detection process, the detection process is performed while circulating the ink at a predetermined timing. I did it like that.

FIG. 17A is a flowchart showing detailed processing contents of the recovery processing executed by the recording apparatus according to the third embodiment. When the recovery process is started, first, time counting is started (S1702). Next, a detection process for detecting the ink ejection state of the nozzle is executed (S1704). Thereafter, based on the detection result of this detection process, it is determined whether the ink ejection state of the print head 8 is good (S1706). The specific processing contents of S1702, S1704, and S1706 are the same as those of S1602, S1210, and S1212 described above, so the description thereof will be omitted.

If it is determined in S1706 that the condition is good, this recovery process ends. If it is determined in S1706 that the condition is not good, it is determined whether a predetermined time has elapsed since the start of the recovery process (S1708). If it is determined in S1708 that the predetermined time has not elapsed, the process returns to S1704 and the detection process is executed again. Further, if it is determined in S1708 that the predetermined time has elapsed, ink circulation is started (S1710). That is, in S1710, the print controller 202 controls the ink supply control unit 209 and the like to circulate ink in the circulation path.

Next, a detection process for detecting the ink ejection state of the nozzles is executed (S1712), and based on the detection result of this detection process, it is determined whether the ink ejection state of the recording head 8 is good (S1714). . The specific processing contents of S1712 and S1714 are the same as those of S1210 and 1212 described above, respectively, so the explanation will be omitted. If it is determined in S1714 that the condition is not good, the process returns to S1712 and the detection process is executed again. Further, if it is determined in S1714 that the condition is good, the circulation of the ink is stopped (S1716), and this recovery processing is ended. That is, in S1716, the print controller 202 controls the ink supply control unit 209 and the like to stop the circulation of ink in the circulation path.

Note that in this recovery process, if it is determined that the condition is not good in S1714, as in the second embodiment, based on the elapsed time after the start of the recovery process or the number of times the detection process was performed in S1712, The recovery process may be terminated.

Further, in this recovery process, ink circulation is started at a timing when a predetermined period of time has elapsed after the start of the recovery process, but the present invention is not limited to this. As in the second embodiment, ink circulation may be started at the timing when the number of times the detection process in S1704 has been performed reaches a predetermined value (predetermined number of times). This will be explained below with reference to FIG. 17(b). FIG. 17(b) is a flowchart showing detailed processing contents of a modified example of the recovery processing executed by the recording apparatus according to the third embodiment. Note that in FIG. 17(b), the same step numbers are used for the same processes as those explained using FIG. 17(a), and detailed explanation thereof will be omitted. In the recovery process of FIG. 17(b), when the recovery process is started, a variable n representing the number of times of detection by the detection process is set to "1" (S1722). If it is determined in S1706 that the ink ejection condition is not good, it is determined whether n has reached a predetermined value (S1724), and if it is determined that n has reached a predetermined value, the process proceeds to S1710. move on. Furthermore, if it is determined that the variable n has not reached the predetermined value, the variable n is incremented (S1726) and the process proceeds to S1704.

As described above, in the recording apparatus 1 according to the third embodiment, ink circulation is started at a predetermined timing in the recovery process, and the detection process is performed while circulating the ink. Thereby, in the recording apparatus 1, when the concentrated ink cannot be removed by the detection process alone, the effect of removing the concentrated ink during the subsequent detection process can be enhanced.

(Fourth embodiment)
Next, an inkjet recording apparatus according to a fourth embodiment of the present invention will be described with reference to FIG. 18. In the following description, the same reference numerals as those used in the first embodiment are used for the same or corresponding configurations as those in the first embodiment described above, and detailed explanation thereof will be omitted.

The fourth embodiment differs from the first, second, and third embodiments in that in the recovery process, the detection process is executed only for a specific ink while circulating the ink. It is different from the form.

Here, the increase in viscosity when liquid components evaporate differs depending on the type of ink. For example, black ink tends to increase in viscosity when the liquid component evaporates compared to color inks such as cyan ink, magenta ink, and yellow ink. Therefore, such black ink is more likely to produce concentrated ink than color ink, and the produced concentrated ink is difficult to remove. Therefore, in this embodiment, inks that tend to thicken more easily than other inks are set in advance, and detection processing is performed for the set inks with enhanced effect of removing concentrated ink. I decided to do so. Note that since the recovery process according to the first embodiment is executed for ink that is not set, in the following explanation, only the recovery process that is executed for the set ink will be explained in detail. That is, in this embodiment, when the start of the recovery process is instructed, the recovery process for the set ink, which will be explained below, and the recovery process according to the first embodiment for the ink that has not been set are performed in parallel. It will be executed.

FIG. 18 is a flowchart showing detailed processing contents of the recovery processing for the set ink, which is executed by the printing apparatus according to the fourth embodiment. When this recovery process is started, first, the set ink circulation is started (S1802). That is, in step S1802, the print controller 202 controls the ink supply control unit 209 and the like to circulate the ink stored in the ROM 203 as an ink that tends to thicken. Note that in this embodiment, the preset inks that tend to thicken are stored in the ROM 203, but when starting the recovery process, the print controller 202 stores information about inks that tend to thicken. It is good if it can be obtained.

Next, a detection process for detecting the ink ejection state of the nozzles is executed (S1804), and based on the detection result of this detection process, it is determined whether the ink ejection state of the print head 8 is good (S1806). . The specific processing contents of S1804 and S1806 are the same as those of S1210 and S1212 described above, respectively, so a description thereof will be omitted.

If it is determined in S1806 that the condition is not good, the process returns to S1804 and the detection process is executed again. Further, if it is determined in S1806 that the condition is good, the circulation of the ink is stopped (S1808), and this recovery processing is ended. That is, in S1808, the print controller 202 controls the ink supply control unit 209 and the like to stop the circulation of the ink that is stored in the ROM 203 as an ink that tends to thicken.

As described above, in the recording apparatus 1 according to the fourth embodiment, the detection process is performed while circulating the ink for ink that tends to increase in viscosity due to evaporation of liquid components. Thereby, in the recording apparatus 1, it becomes possible to enhance the effect of removing concentrated ink from ink that tends to thicken in the recovery process.

(Fifth embodiment)
Next, an inkjet recording apparatus according to a fifth embodiment of the present invention will be described with reference to FIG. 19. In the following description, the same reference numerals as those used in the first embodiment are used for the same or corresponding configurations as those in the first embodiment described above, and detailed explanation thereof will be omitted.

The fifth embodiment differs from the first, second, and third embodiments in that in the recovery process, the presence or absence of ink circulation is changed during the detection process according to the ink density information. The configuration is different from the fourth embodiment. That is, the recording apparatus 1 according to the present embodiment uses the recovery process to eliminate the ink ejection failure caused by the increase in the concentration of ink in the circulation path due to the recording operation. That is, in this embodiment, the recovery process is executed after the recording process.

FIG. 19 is a flowchart showing detailed processing contents of the recovery processing executed by the recording apparatus according to the fifth embodiment. When this recovery process is started, first, the ink density Nc is obtained (S1902). That is, in S1902, the print controller 202 obtains density Nc, which is density information, for each ink color.

Here, the print controller 202 obtains the density N _{x +1} of the ink in the circulation path for each printing operation. Then, the obtained value is overwritten and stored in, for example, the ROM 203 as the concentration Nc of the ink in the circulation path. Note that the concentration N _X+1 is obtained using the following equation (1).
N _x+1 = (N _x × (Jn-In))/(Jn-In-V)... (1)

N _X+1 is the current ink density. N _x is the density of ink before the printing operation. Regarding N _X+1 and N _X , if the concentration is 5% by weight, the value will be 0.05. Jn is the amount of ink in the circulation path before the printing operation, for example, the amount of ink filled in the circulation path. In is the amount of ink ejected by the recording operation, and can be obtained based on the recording data. V is the amount of evaporation of ink from the circulation path, and is set in advance.

Therefore, in S1902, the print controller 202 acquires the ink density Nc stored in the ROM 203. Next, it is determined whether the obtained concentration Nc exceeds a predetermined concentration (S1904). In S1904, for example, it is determined whether the concentration Nc exceeds 0.089, that is, 8.9% by weight. Regarding the predetermined density, the lowest density at which thickening of the ink cannot be efficiently resolved only by the ink ejection operation through the detection process is experimentally obtained for each type of ink, for example. Alternatively, the predetermined density may be the lowest density at which the ink ejection condition becomes poor.

If it is determined in S1904 that the concentration Nc exceeds the predetermined concentration, ink circulation is started (S1906). That is, if the concentration Nc exceeds a predetermined concentration, the liquid components in the ink in the circulation path will continue to evaporate, and the increase in viscosity cannot be efficiently resolved by the ejection operation alone. will be held. Thereafter, a detection process for detecting the ink ejection state of the nozzles is executed (S1908), and based on the detection result of this detection process, it is determined whether the ink ejection state of the recording head 8 is good (S1910). The specific processing contents of S1908 and S1910 are the same as those of S1210 and 1212 described above, respectively, so a description thereof will be omitted.

Here, the amount of ink in the circulation path decreases due to the ink ejection operation performed by the detection process. As a result, when the amount of ink in the sub-tank 151 constituting the circulation path becomes less than a predetermined amount, ink is replenished from the main tank 141 under the control of the ink supply control section 209. Therefore, the viscosity of the ink in the circulation path is reduced, and the ink ejection condition is improved. If it is determined in S1910 that the condition is not good, the process returns to S1908 and the detection process is executed again. Further, if it is determined in S1910 that the condition is good, the circulation of the ink is stopped (S1912), and this recovery processing is ended.

On the other hand, if it is determined in S1904 that the concentration Nc is less than or equal to the predetermined concentration, a detection process for detecting the ink ejection state of the nozzle is executed (S1914). Thereafter, based on the detection result of this detection process, it is determined whether the ink ejection state of the recording head 8 is good (S1916). The specific processing contents of S1914 and S1916 are the same as those of S1210 and S1212 described above, respectively, so a description thereof will be omitted. If it is determined in S1916 that the condition is not good, the process returns to S1914 and the detection process is executed again. Further, if it is determined in S1916 that the condition is not good, this recovery process is ended.

As described above, in the recording apparatus 1 according to the fifth embodiment, when the thickened ink after the recording process exceeds a predetermined density, the detection process is performed while the ink is being circulated. Thereby, in the recording apparatus 1, it becomes possible to efficiently improve the ink ejection condition for ink that exceeds a predetermined density.

(Other embodiments)
Note that the above embodiment may be modified as shown in (1) to (4) below.

(1) In the above embodiment, the timing to start the recovery process is when the power of the recording device is turned on, after a print instruction is input, and before the recording process is executed. It may also be performed after a maintenance operation for the recording head 8 is performed. In this case, for example, it will be executed after the wiping operation by the blade wiper unit 171.

With the recording operation, the liquid component in the ink adhering to the ejection port surface 8a evaporates and changes to a thickened state. When the blade wiper unit 171 performs a wiping operation with the adhered ink thickened, the thickened ink is pushed into the ejection port 86, and concentrated ink is located near the ejection port 86. The recovery process according to this embodiment will be applied to such a situation. That is, by performing a detection process that involves ejecting ink without circulating the ink, the thickened ink (concentrated ink) pushed into the ejection port 86 is suppressed from flowing into the downstream side of the circulation path. It becomes possible to remove thickened ink.

Furthermore, the timing for performing the recovery process may be, for example, when the time during which the power of the recording apparatus 1 is turned off exceeds a predetermined time (for example, 64 hours). Further, the timing for performing the recovery process may be when the non-circulation time during which ink is not circulated exceeds a predetermined time, and may be before the next printing operation. In this case, the ink may simply be circulated.

(2) The present invention provides a program that implements one or more of the functions of the above embodiments to a system or device via a network or a storage medium, and one or more processors in the computer of the system or device executes the program. This can also be realized by reading and executing processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions. Although not specifically described in the above embodiments, the recording apparatus 1 may be configured to be able to select the recovery processing in each of the above embodiments. Further, although not specifically described in the above embodiment, the controller unit 100 and the print engine unit 200 may be installed in the recording apparatus 1, or their functions may be transferred to an external device connected to the recording apparatus 1. You may also have it executed.

(3) In the above embodiment, the printing apparatus 1 prints using five types of ink of different colors, but the invention is not limited to this. That is, recording may be performed using one or more types of ink. Furthermore, the type of ink is not limited to different colors, and inks with different characteristics may be used. Furthermore, in the above embodiment, the ink is circulated when predetermined conditions are met, such as the timing when a predetermined time has elapsed, and the timing when recovery processing is executed for a set ink or ink that exceeds a predetermined density. However, it is not limited to this. The predetermined conditions for circulating ink may be configured to be settable.

(4) The embodiments described above and the various forms shown in (1) to (3) above may be combined as appropriate.

8 Recording head 91 Temperature detection element 202 Print controller 209 Ink supply control section

Claims (18)

a recording means equipped with a plurality of nozzles that eject ink using heat generated by a recording element;
a circulation means capable of circulating ink in a circulation path including the recording means;
An inkjet recording device comprising:
a detection means for detecting the ink ejection state in the nozzle based on the detected temperature of the nozzle when the ink is ejected;
During a recovery process to eliminate ink ejection failure caused by ink concentration, ejecting ink from the nozzle by causing the recording element to generate heat without circulating the ink by the circulation means;
a control means for controlling the detection means to detect the state of ink ejection in the nozzle;
determining means for determining whether the ink ejection state in the recording means is good or bad based on the number of first nozzles for which ink is not normally ejected by the detection means;
The recording means includes a plurality of chips in which nozzles for ejecting ink are arranged,
The determining means determines the ink ejection state in each of the chips, and based on the determination, determines the ink ejection state in the recording means,
The determining means determines the ink ejection state of the chips based on a threshold value depending on the position where the chips are arranged, and the threshold value is set low in the central part in the arrangement direction of the chips; It is set higher on the end side in the direction,
The control means repeats the detection by the detection means until the determination means determines that the ink ejection state in the recording means is good.
An inkjet recording device characterized by: The inkjet recording apparatus according to claim 1, wherein the detection means detects based on a temperature change value corresponding to a change in detected temperature. 3. The inkjet recording apparatus according to claim 1 , wherein the determination means makes the determination based on a ratio of the number of the first nozzles to the total number of nozzles. The recording means ejects a plurality of types of ink,
4. The determining means determines the ink ejection state for each type of ink, and determines the ink ejection state in the recording means based on the determination. inkjet recording device. The recording means ejects a plurality of types of ink at the chip,
The determining means determines the ejection state of each type of ink in the chip, and determines the ink ejection state in the recording means based on the determination of the ink ejection state in the chip according to the determination. The inkjet recording apparatus according to any one of claims 1 to 4 . 6. The determining means makes the determination based on a threshold value depending on the type of ink, and the threshold value is set low for black ink and high for yellow ink. The inkjet recording device described in . The determination means is based on the ratio of the number of first nozzles to the number of nozzles obtained by subtracting the number of second nozzles that are already said to be not ejecting ink normally from the total number of nozzles that eject the ink. The inkjet recording apparatus according to any one of claims 1 to 6, wherein the inkjet recording apparatus performs a determination. 8. In the recovery process, when a predetermined condition is satisfied, the control means controls the ink to be detected by the detection means while circulating the ink by the circulation means. The inkjet recording device according to item 1. The inkjet recording apparatus according to claim 8 , wherein the predetermined condition is a timing at which a predetermined time has elapsed after the start of the recovery process. 9. The inkjet recording apparatus according to claim 8 , wherein the predetermined condition is a timing at which the number of times of detection detected by the detection means exceeds a predetermined number of times. 9. The inkjet recording apparatus according to claim 8 , wherein the predetermined condition is a timing at which the recovery process is executed for the set ink. 12. The inkjet recording apparatus according to claim 11 , wherein the set ink is an ink that tends to thicken due to evaporation of liquid components. 9. The inkjet recording apparatus according to claim 8 , wherein the predetermined condition is a timing at which the recovery process is executed for ink exceeding a predetermined density. 14. The recovery process ends at a predetermined timing when the determination means continues to determine that the ink ejection state in the recording means is not good. The inkjet recording device described above. further comprising wiping means for performing a wiping operation on the recording means,
The inkjet recording apparatus according to any one of claims 1 to 14 , wherein the recovery process is executed after the wiping operation. a recording means equipped with a plurality of nozzles that eject ink using heat generated by a recording element;
a circulation means capable of circulating ink in a circulation path including the recording means;
a detection means for detecting the ink ejection state in the nozzle based on the detected temperature of the nozzle when the ink is ejected;
When performing recovery processing to eliminate ink ejection failure caused by ink density, the recording element generates heat to remove ink from the nozzle without circulating the ink by the circulation means. A control device configured to eject ink and detect the ejection state of ink in the nozzle by the detection means ,
a determination means for determining whether the ink ejection state in the recording means is good or bad based on the number of first nozzles for which ink is not normally ejected by the detection means;
The recording means includes a plurality of chips in which nozzles for ejecting ink are arranged,
The determining means determines the ink ejection state in each of the chips, and based on the determination, determines the ink ejection state in the recording means,
The determining means determines the ink ejection state in the chip based on a threshold value that corresponds to the position where the chip is arranged, and the threshold value is set low in the central part in the arrangement direction of the chip; It is set higher on the end side in the direction,
A control device characterized in that the detection by the detection means is repeated until the determination means determines that the ink ejection state in the recording means is good . 17. The control device according to claim 16 , wherein when a predetermined condition is satisfied, control is performed so that the detecting means performs the detection while the ink is being circulated by the circulating means. A program for causing a computer to function as the control device according to claim 16 or 17 .

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