JP2021070279A - Inkjet recording device, control device and program - Google Patents

Abstract

To provide a technique capable of shortening time required for recovery processing.SOLUTION: The inkjet recording device, which includes recording means having a plurality of nozzles for discharging ink by heat generation of a recording element and circulation means for executing circulation of ink on a circulation path including the recording means, has detection means for detecting an ink discharge state in a nozzle on the basis of a nozzle detection temperature when the ink is discharged, and control means which discharges the ink from the nozzle by generating heat of the recording element without circulating the ink by the circulation means during recovery processing of solving discharge failures of the ink caused by concentration of the ink, and controls the detection means to detect the ink discharge state in the nozzle.SELECTED DRAWING: Figure 12

Description

The present invention relates to an inkjet recording device that executes a recovery process for satisfactorily maintaining and recovering an ink ejection state from a recording head, a control device that controls the inkjet recording device, and a program.

In an inkjet recording device, the ink in the nozzle for ejecting ink thickens with the passage of time, which causes ejection failure due to clogging of the nozzle and misalignment of landing. Patent Document 1 discloses a technique for eliminating ejection defects due to such thickened ink.

Japanese Unexamined Patent Publication No. 2011-62847

However, in Patent Document 1, the ink ejection state from the nozzle is detected, and when it is not detected that the ink ejection state is good, a recovery operation for recovering the ink ejection state is performed, and then a recovery operation is performed. , The ink ejection state is detected again. Therefore, it takes time for the recovery process as a series of processes for detecting the ink ejection state, performing the recovery operation, and detecting that the ink ejection state is good.

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

In order to achieve the above object, the present invention includes a recording means provided with a plurality of nozzles for ejecting ink by heat generation of the recording element, and a circulation means capable of executing ink circulation in a circulation path including the recording means. An inkjet recording device equipped with a detection means for detecting the ink ejection state in the nozzle based on the detection temperature of the nozzle when the ink is ejected, and eliminating an ink ejection defect due to the ink density. During the recovery process, the recording element is generated to generate heat to eject ink from the nozzle without circulating the ink by the circulation means, and the detection means controls to detect the ink ejection state in the nozzle. It is characterized by having.

According to the present invention, the time required for the recovery process can be shortened.

It is a figure when the recording device is in a standby state. It is a control block diagram of a recording device. It is a figure when the recording apparatus is in a recording state. It is a transport route diagram of the recording medium supplied from the 1st cassette. It is a figure when the recording device is in a maintenance state. It is a perspective view which shows the structure of the maintenance unit. It is a schematic block diagram of an ink supply system. It is a figure explaining the flow of ink in the flow path including a discharge port. It is a block diagram of the vicinity of a discharge port of a recording element substrate. It is a figure explaining the detection temperature by a temperature detection element. It is a figure explaining the removal of concentrated ink by circulation and ejection of ink. It is a flowchart of the recording process and the recovery process by the recording apparatus of 1st Embodiment. It is a table which shows the threshold value used in the 1st determination method. It is a table which shows the threshold value used in the 2nd determination method. It is a figure explaining the 3rd determination method. It is a flowchart of the recovery process by the recording apparatus of 2nd Embodiment. It is a flowchart of the recovery process by the recording apparatus of 3rd Embodiment. It is a flowchart of the recovery process by the recording apparatus of 4th Embodiment. It is a flowchart of the recovery process by the recording apparatus of 5th Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments do not limit the present invention, and not all combinations of features described in the present embodiment are essential to the means of solving the present invention. The relative arrangements, shapes, and the like of the components described in the embodiments are merely examples, and the scope of the present invention is not limited to them. In the following embodiment, an inkjet recording device will be described as an example of a liquid discharge device including a liquid discharge head that discharges droplets.

(First Embodiment)
First, the inkjet recording apparatus according to the 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 recording device 1 (hereinafter, recording device 1) used in the present embodiment. In the figure, the x direction indicates the horizontal direction, the y direction (the direction perpendicular to the paper surface) indicates the direction in which the discharge ports are arranged in the recording head 8 described later, and the z direction indicates the vertical direction.

The recording device 1 is a multifunction device including a printing unit 2 and a scanner unit 3, and various processing related to a recording operation and a reading operation can be executed individually or in conjunction with the printing unit 2 and the scanner unit 3. The scanner unit 3 includes an ADF (auto document feeder) and an FBS (flatbed scanner), and reads a document automatically fed by the ADF and a document placed on the FBS document stand by the user (scanning). )It can be performed. Although the present embodiment is a multifunction device having both the printing unit 2 and the scanner unit 3, the embodiment may not include the scanner unit 3. FIG. 1 shows a state in which the recording device 1 is in a standby state in which neither a recording operation nor a reading operation is performed.

In the print unit 2, a first cassette 5A and a second cassette 5B for accommodating the recording medium (cut sheet) S are detachably installed on the bottom of the housing 4 in the vertical direction. A relatively small recording medium up to A4 size is housed in the first cassette 5A, and a relatively large recording medium up to A3 size is housed in the second cassette 5B in a flat stack. In the vicinity of the first cassette 5A, a first feeding unit 6A for separating and feeding the contained recording media one by one is provided. Similarly, a second feeding unit 6B is provided in the vicinity of the second cassette 5B. When the recording operation is performed, the recording medium S is selectively fed from one of the cassettes.

The transfer 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 transfer mechanisms for guiding the recording medium S in a predetermined direction. The transfer roller 7 is a drive roller arranged on the upstream side and the downstream side of the recording head 8 and driven by a transfer motor (not shown). The pinch roller 7a is a driven roller that rotates by niping the recording medium S together with the transport roller 7. The discharge roller 12 is a drive roller arranged on the downstream side of the transfer roller 7 and driven by a transfer motor (not shown). The spur 7b sandwiches and conveys the recording medium S together with the transfer roller 7 and the discharge roller 12 arranged on the downstream side of the recording head 8.

The guide 18 is provided in the transport path of the recording medium S and guides the recording medium S in a predetermined direction. The inner guide 19 has a curved side surface with a member extending in the y direction, 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 the double-sided recording operation. The discharge tray 13 is a tray for loading and holding the recording medium S discharged by the discharge roller 12 after the recording operation is completed.

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

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

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

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

In the controller unit 100, the main controller 101 composed of the CPU controls the entire recording device 1 with the RAM 106 as the work area according to the 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, a predetermined image process is performed on the image data received by the image processing unit 108 according to the instruction of the main controller 101. Give. Then, the main controller 101 transmits the image data subjected to the image processing to the print engine unit 200 via the print engine I / F 105.

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 (USB memory or the like) connected to the recording device 1. Is also good. The communication method used for wireless communication and wired communication is not limited. For example, Wi-Fi (Wireless Fidelity) (registered trademark) and Bluetooth (registered trademark) can be applied as a communication method used for wireless communication. Further, as a communication method used for wired communication, USB (Universal Serial Bus) or the like can be applied. Further, for example, when a read command is input from the host device 400, 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 for the user to input / output to / from the recording device 1. The user can instruct operations such as copying and scanning via the operation panel 104, set the print mode, and recognize the information of the recording device 1.

In the print engine unit 200, the print controller 202 configured by the CPU controls various mechanisms included in the print unit 2 while using the RAM 204 as a work area according to the 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 stored image data into the recording data so that the recording head 8 can be used for the recording operation. When the recorded data is generated, the print controller 202 causes the recording head 8 to execute a recording operation based on the recorded data via the head I / F 206. At this time, the print controller 202 drives the feeding units 6A and 6B, the transport roller 7, the discharge roller 12, and the flapper 11 shown in FIG. 1 via the transport control unit 207 to transport the recording medium S. According to the instruction of the print controller 202, the recording operation by the recording head 8 is executed in conjunction with the conveying operation of the recording medium S, and the printing process is performed.

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

In the scanner engine unit 300, the main controller 101 controls the hardware resources of the scanner controller 302 while using the RAM 106 as a work area according to the programs and various parameters stored in the ROM 107. As a result, various mechanisms included in the scanner unit 3 are controlled. For example, when the main controller 101 controls the hardware resources in the scanner controller 302 via the controller I / F 301, the document loaded on the ADF by the user is conveyed via the transfer control unit 304 and read by the sensor 305. .. Then, the scanner controller 302 saves the read image data in the RAM 303. The print controller 202 can cause the recording head 8 to execute a recording operation based on the image data read by the scanner controller 302 by converting the image data acquired as described above into the recording data. ..

FIG. 3 shows when the recording device 1 is in the recording state. Compared with the standby state shown in FIG. 1, the cap unit 10 is separated from the discharge port surface 8a of the recording head 8, and the discharge port surface 8a faces the platen 9. In the present embodiment, the plane of the platen 9 is tilted by about 45 degrees with respect to the horizontal direction, and the discharge port surface 8a of the recording head 8 at the recording position is also in the horizontal direction so that the distance from the platen 9 is kept constant. It is tilted about 45 degrees with respect to.

When the recording head 8 is moved from the standby position shown in FIG. 1 to the recording position shown in FIG. 3, the print controller 202 uses the maintenance control unit 210 to lower the cap unit 10 to the retracted position shown in FIG. As a result, the discharge port surface 8a of the recording head 8 is separated from the cap member 10a. After that, the print controller 202 is rotated by 45 degrees while adjusting the height of the recording head 8 in the vertical direction by using the head carriage control unit 208, so that the discharge 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 of the above.

Next, the transport path of the recording medium S in the printing unit 2 will be described. When the recording command is input, the print controller 202 first moves the recording head 8 to the recording position shown in FIG. 3 by using the maintenance control unit 210 and the head carriage control unit 208. After that, the print controller 202 uses the transport control unit 207 to drive either the first feeding unit 6A or the second feeding unit 6B according to the recording command, and feeds the recording medium S.

4 (a) to 4 (c) are diagrams showing a transport path when the A4 size recording medium S housed in the first cassette 5A is fed. The recording medium S loaded on the top of the first cassette 5A is separated from the second and subsequent recording media by the first feeding unit 6A, and while being nipated by the transport roller 7 and the pinch roller 7a, the platen 9 It is conveyed toward the recording area P between the recording head 8 and the recording head 8. FIG. 4A shows a transport state immediately before the tip of the recording medium S reaches the recording area P. The traveling direction of the recording medium S is changed from the horizontal direction (x direction) to a direction inclined by about 45 degrees with respect to the horizontal direction while being fed to the first feeding unit 6A and reaching the recording area P. To.

In the recording area P, ink is ejected toward the recording medium S from a plurality of ejection ports provided in the recording head 8. The back surface of the recording medium S in the area to which the 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. The recording medium S after the ink is applied passes through the left side of the flapper 11 whose tip is tilted to the right while being guided by the transport roller 7 and the spur 7b, and goes upward in the vertical direction of the recording device 1 along the guide 18. Be transported. FIG. 4B shows a state in which the tip of the recording medium S passes through the recording area P and is conveyed upward in the vertical direction. The traveling direction of the recording medium S is changed vertically upward by the transport roller 7 and the spur 7b from the position of the recording region P tilted by about 45 degrees with respect to the horizontal direction.

The recording medium S is conveyed upward in the vertical direction and then discharged to the discharge tray 13 by the discharge roller 12 and the spur 7b. FIG. 4C shows a state in which the tip of the recording medium S passes through the discharge roller 12 and is discharged to 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 housed 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 loaded on the top of the second cassette 5B is separated from the second and subsequent recording media by the second feeding unit 6B, and is nipped into the transfer roller 7 and the pinch roller 7a. It is conveyed toward the recording area P between the platen 9 and the recording head 8.

When double-sided recording of the A4 size recording medium S is performed, the recording operation is performed on the second surface (back surface) after recording the first surface (front surface). Since the transfer process for recording the first surface is the same as in FIGS. 4 (a) to 4 (c), the description thereof will be omitted here. When the recording operation on the first surface by the recording head 8 is completed and the rear end of the recording medium S passes through the flapper 11, the print controller 202 reversely rotates the transport roller 7 to record the recording medium S inside the recording device 1. Transport to. At this time, since the tip of the flapper 11 is controlled to be tilted to the left by an actuator (not shown), the tip of the recording medium S (the rear end in the recording operation of the first surface) passes through the right side of the flapper 11. It is transported downward in the vertical direction.

After that, the recording medium S is conveyed along the curved outer peripheral surface of the inner guide 19, and is 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 discharge port surface 8a of the recording head 8. The subsequent transport route is the same as in the case of the first surface recording shown in FIGS. 4 (b) and 4 (c). When the tip of the recording medium S passes through the recording area P and is conveyed upward in the vertical direction, the flapper 11 is controlled by an actuator (not shown) so that the tip is tilted to the right.

Next, the maintenance operation for the recording head 8 will be described. As described with reference to FIG. 1, the maintenance unit 16 of the present embodiment includes a cap unit 10 and a wiping unit 17, and these are operated at a predetermined timing to perform a maintenance operation.

FIG. 5 is a diagram when the recording device 1 is in the maintenance state. When the recording head 8 is moved 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 upward in the vertical direction and the cap unit 10 downward in the vertical direction. Then, the print controller 202 moves the wiping unit 17 from the retracted position to the right in FIG. After that, the print controller 202 moves the recording head 8 downward in the vertical direction to a maintenance position where maintenance operation is possible.

On the other hand, when the recording head 8 is moved 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 upward in the vertical direction while rotating the recording head 8 by 45 degrees. Then, the print controller 202 moves the wiping unit 17 to the right from the retracted position. After that, the print controller 202 moves the recording head 8 downward in the vertical direction to a maintenance position where the maintenance operation by the maintenance unit 16 is possible.

FIG. 6A is a perspective view showing a state in which the maintenance unit 16 is in the standby position, and FIG. 6B is a perspective view showing a state in which the maintenance unit 16 is in the maintenance position. FIG. 6A corresponds to FIG. 1 and FIG. 6B corresponds to FIG. When the recording head 8 is in the standby position, the maintenance unit 16 is in the standby position shown in FIG. 6A, the cap unit 10 is moving upward in the vertical direction, and the wiping unit 17 is housed inside the maintenance unit 16. 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. Further, the cap unit 10 also has a function of collecting the ink ejected to the cap member 10a by preliminary ejection or the like and sucking the collected ink into a suction pump (not shown).

On the other hand, in the maintenance position shown in FIG. 6B, the cap unit 10 is moving downward in the vertical direction, 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, blade wipers 171a for wiping the discharge port surface 8a along the x direction are arranged in the y direction by a length corresponding to the arrangement region of the discharge port. 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 in a state where the recording head 8 is positioned at a height capable of contacting the blade wiper 171a. By this movement, the ink and the like adhering to the discharge port surface 8a are wiped off by the blade wiper 171a.

At the entrance of the maintenance unit 16 when the blade wiper 171a is housed, a wet wiper cleaner 16a for removing ink adhering to the blade wiper 171a and applying a wet liquid to the blade wiper 171a is arranged. Each time the blade wiper 171a is housed in the maintenance unit 16, deposits are removed by the wet wiper cleaner 16a and a wet liquid is applied. Then, when the discharge port surface 8a is wiped next, the wet liquid is transferred to the discharge port surface 8a to improve 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 opening in the y direction, and a vacuum wiper 172c mounted on the carriage 172b. The vacuum wiper 172c is arranged so that the discharge port surface 8a can be wiped 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, the ink or the like adhering to the discharge port surface 8a of the recording head 8 is sucked into the suction port while being wiped by the vacuum wiper 172c. At this time, the flat plate 172a and the positioning pins 172d provided at both ends of the opening are used for aligning the discharge port surface 8a with respect to the vacuum wiper 172c.

In the present embodiment, it is possible to carry out a first wiping process in which the wiping operation by the blade wiper unit 171 is performed and the wiping operation by the vacuum wiper unit 172 is not performed, and a second wiping process in which both wiping processes are sequentially performed. .. When performing the first wiping process, the print controller 202 first pulls out the wiping unit 17 from the maintenance unit 16 in a state where the recording head 8 is retracted vertically upward from the maintenance position shown 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. By this movement, the ink and the like adhering to the discharge 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 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 upward in the vertical direction to bring the cap member 10a into close contact with the discharge port surface 8a of the recording head 8. Then, the print controller 202 drives the recording head 8 in that state to perform preliminary ejection, and sucks the ink collected in the cap member 10a 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 in a state where the recording head 8 is retracted vertically upward from 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. As a result, the 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 with the recording head 8 retracted vertically upward from the maintenance position shown in FIG. Subsequently, the print controller 202 positions the discharge 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. The print controller 202 retracts the recording head 8 vertically upward, stores the wiping unit 17, and then, similarly to the first wiping process, pre-discharges the recording head 8 into the cap member and sucks the collected ink. Do the action.

(Ink supply unit)
Next, the flow path configuration of the ink circulation system of the present embodiment will be described with reference to FIG. 7. FIG. 7 is a diagram showing a flow path configuration of an ink circulation system including an ink supply unit 15 used in the inkjet recording apparatus 1 of the present 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, such a configuration is actually prepared for each ink color. The ink supply unit 15 is basically controlled by the ink supply control unit 209 shown in FIG. Hereinafter, each configuration of the ink supply unit 15 will be described.

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

The sub tank 151 accommodating a predetermined amount of ink is connected to a supply flow path C2 for supplying ink to the recording head 8 and a collection flow path C4 for collecting ink from the recording head 8. That is, the sub tank 151, the supply flow path C2, the recording head 8, and the recovery flow path C4 form a circulation path that serves as a circulation flow path for ink to circulate. Further, the sub tank 151 is connected to the flow path C0 through which air flows.

The sub tank 151 is provided with a liquid level detecting 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 the conduction current between the plurality of pins. The pressure reducing pump P0 is a negative pressure generating source for reducing the pressure inside the tank of 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 houses the ink supplied to the sub tank 151. The main tank 141 has a structure that can be attached to and detached from the recording device main body. 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 flow path C1 connecting the sub tank 151 and the main tank 141.

When the ink supply control unit 209 detects that the amount of ink in the sub tank 151 is less than a predetermined amount by the liquid level detecting means 151a, the ink supply control unit 209 closes the atmosphere release valve V0, the supply valve V2, the recovery valve V4, and the head replacement valve V5. .. Further, the ink supply control unit 209 opens the tank supply valve V1. In this state, the ink supply control unit 209 operates the decompression pump P0. Then, the inside of the sub tank 151 becomes a negative pressure, and ink is supplied from the main tank 141 to the sub tank 151. When the liquid level detecting means 151a detects that the amount of 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 flow path C2 is a flow path for supplying ink from the sub tank 151 to the recording head 8, and a supply pump P1 and a supply valve V2 are arranged in the middle of the flow path. During the recording operation, by driving the supply pump P1 with the supply valve V2 open, the ink can be circulated in the circulation path while supplying the ink to the recording head 8. The amount of ink ejected by the recording head 8 per unit time 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 the ejection operation that maximizes the ink consumption per unit time.

The relief flow path C3 is an upstream side of the supply valve V2 and is a flow path connecting the upstream side and the downstream side of the supply pump P1. A relief valve V3, which is a differential pressure valve, is arranged in the middle of the relief flow path C3. The relief valve V3 is spring-loaded rather than being opened and closed by a drive mechanism, and is configured to open when a predetermined pressure is reached. For example, the ink supply amount per unit time supplied from the supply pump P1 to the IN flow path 80b is the discharge amount per unit time of the recording head 8 and the ink flow rate per unit time flowing from the recovery pump P2 to the recovery flow path C4. It is assumed that the value is larger than the total value of. In this case, the relief valve V3 is opened according to the pressure acting on itself. As a result, a cyclic flow path composed of a part of the supply flow path C2 and the relief flow path C3 is formed. By providing the relief flow path C3, the amount of ink supplied to the recording head 8 can be adjusted according to the amount of ink consumed by the recording head 8, and the pressure in the circulation path can be stabilized regardless of the image data. ..

The recovery flow path C4 is a flow path for collecting ink from the recording head 8 to the sub tank 151, and a recovery pump P2 and a recovery valve V4 are arranged in the middle of the flow path. When the ink is circulated in the circulation path, the recovery pump P2 acts as a negative pressure generating source and sucks the ink from the recording head 8. By driving the recovery pump P2, an appropriate pressure difference is generated between the IN flow path 80b and the OUT flow path 80c in the recording head 8, and ink 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 the recording operation is not performed, that is, when the ink is not circulated in the circulation path. In the circulation path of the present 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 driven, ink may flow back from the sub tank 151 to the recording head 8 due to the head difference between the sub tank 151 and the recording head 8. In order to prevent such backflow, a recovery valve V4 is provided in the recovery flow path C4 in this embodiment.

The supply valve V2 also functions as a valve for preventing the supply of ink from the sub tank 151 to the recording head 8 when the recording operation is not performed, that is, when the ink is not 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 in which ink is not stored) of the sub tank 151, and a head replacement valve V5 is arranged in the middle of the flow path. One end of the head replacement flow path C5 is on the upstream side of the recording head 8 in the supply flow path C2 and is connected to the downstream side of the supply valve V2. The other end of the head exchange flow path C5 is connected above the sub tank 151 and communicates with the air chamber inside the sub tank 151. The head exchange flow path 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 device 1. The head exchange valve V5 is controlled by the ink supply control unit 209 so as to be closed except when the recording head 8 is filled with ink and when the ink is collected from the recording head 8.

Next, the flow path configuration in the recording head 8 will be described. The ink supplied to the recording head 8 from the supply flow path C2 passes through the filter 83 and is then supplied to the first negative pressure control unit 81 and the second negative pressure control unit 82. In the first negative pressure control unit 81, the control pressure is set to a weak negative pressure (a negative pressure having a small pressure difference from the atmospheric pressure), for example, −90 mmAq. In the second negative pressure control unit 82, the control pressure is set to a strong negative pressure (a negative pressure having a large pressure difference from the atmospheric pressure), for example, −180 mmAq. The pressure in the first negative pressure control unit 81 and the second negative pressure control unit 82 is generated in an appropriate range by driving the recovery pump P2.

A plurality of recording element substrates 80a in which a plurality of ejection ports are arranged are arranged in the ink ejection unit 80, and a long row of ejection ports is formed. A common supply flow path 80b (IN flow path) for guiding the ink supplied from the first negative pressure control unit 81 and a common recovery flow path for guiding the ink supplied from the second negative pressure control unit 82. The 80c (OUT flow path) also extends in the arrangement direction of the recording element substrate 80a. Further, each recording element substrate 80a is formed with an individual supply flow path connected to the common supply flow path 80b and an individual recovery flow path connected to the common recovery flow path 80c. Therefore, in each recording element substrate 80a, an ink flow that flows in from the common supply flow path 80b, which has a relatively weak negative pressure, and flows out to the common recovery flow path 80c, which has a relatively strong negative pressure. Will be generated. In the path between the individual supply flow path and the individual recovery flow path, a pressure chamber that communicates with each discharge port and is filled with ink is provided, and ink flows even in the discharge port and pressure chamber where recording is not performed. Occurs. When the ejection operation is performed on the recording element substrate 80a, a part of the ink moving from the common supply flow path 80b to the common recovery flow path 80c is consumed by being ejected from the ejection port, but the ink that is not ejected is consumed. It moves to the recovery flow path C4 via the common recovery flow path 80c.

FIG. 8A is an enlarged plan schematic view of a part of the recording element substrate 80a, and FIG. 8B is a schematic cross-sectional view taken along the cross-sectional line VIIIb-VIIIb of FIG. 8A. The recording element substrate 80a is provided with a pressure chamber 85 filled with ink and a discharge port 86 for ejecting ink. In the pressure chamber 85, a recording element 84 is provided at a position facing the discharge port 86. Further, the recording element substrate 80a is formed with a plurality of individual supply flow paths 88 connected to the common supply flow path 80b and a plurality of individual recovery flow paths 89 connected to the common recovery flow path 80c for each discharge port 86.

With the above configuration, in the recording element substrate 80a, a flow is generated in which ink flows in from the common supply flow path 80b, which has a relatively weak negative pressure, and flows out to the common recovery flow path 80c, which has a relatively strong negative pressure. .. More specifically, the ink flows in the order of common supply flow path 80b → individual supply flow path 88 → pressure chamber 85 → individual recovery flow path 89 → common recovery flow path 80c. When the ink is ejected by the recording element 84, a part of the ink moving from the common supply flow path 80b to the common recovery flow path 80c is ejected from the ejection port 86 and is ejected to the outside of the recording head 8. On the other hand, the ink not ejected from the ejection port 86 is recovered to the recovery channel C4 via the common recovery channel 80c.

Under the above configuration, when performing the 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 the pump P1 and the recovery pump P2. As a result, the circulation path of the sub tank 151 → the supply flow path C2 → the recording head 8 → the recovery flow path C4 → the sub tank 151 is established. When the ink supply amount per unit time from the supply pump P1 is larger than the total value of the discharge 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 from the supply flow path C2. Ink flows into C3. As a result, the flow rate of the ink flowing into the recording head 8 from the supply flow path C2 is adjusted.

When the recording operation is not performed, the ink supply control unit 209 stops the supply pump P1 and the recovery pump P2, and closes the atmosphere release valve V0, the supply valve V2, and the recovery valve V4. As a result, the flow of ink in the recording head 8 is stopped, and the backflow due to the head difference between the sub tank 151 and the recording head 8 is also suppressed. Further, by closing the air 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 air release valve V0, the tank supply valve V1, the supply valve V2, and the recovery valve V4, opens the head exchange valve V5, and drives the pressure reducing pump P0. To do. As a result, the inside of the sub tank 151 becomes a negative pressure state, and the ink in the recording head 8 is collected in the sub tank 151 via the head exchange flow path C5. As described above, the head exchange valve V5 is a valve that is closed during normal recording operation or standby, and is opened when ink is collected from the recording head 8. When filling the recording head 8 and filling the head replacement flow path C5 with ink, the head replacement valve V5 is also opened.

The circulation flow path of the present embodiment has a flow path configuration in which ink passes through the pressure chamber 85, but a flow path configuration in which ink does not pass through the pressure chamber 85 may be used. Specifically, for example, the ink may flow directly from the common supply flow path 80b to the recovery flow path C4. In the present embodiment, as described above, the ink supply control unit 209 and various pumps function as a circulation unit capable of executing ink circulation in the circulation path including the recording head 8.

(Detection of ink ejection status at the nozzle)
Next, a configuration and a detection method for detecting the ink ejection state will be described. In the present embodiment, the temperature detecting element 91 provided on the recording element substrate 80a of the recording head 8 is used to detect the ink ejection state of each nozzle. That is, for each nozzle, it is detected whether or not the ink is normally ejected. The detected ink ejection state of each nozzle is used when determining the ink ejection state of the recording head 8 described later. Further, in the following description, the nozzle represents a configuration for ejecting ink provided on the recording element substrate 80a including the recording element 84, the pressure chamber 85, and the ejection port 86.

FIG. 9A is a diagram showing a recording element 84 and a temperature detecting element 91 provided on the recording element substrate 80a. 9 (b) is a sectional view taken along line IXb-IXb of FIG. 9 (a), and FIG. 9 (c) is a sectional view taken along line IXc-IXc of FIG. 9 (a). The recording element 84 is an ejection energy generating element that generates ejection energy for ejecting ink. In the present embodiment, the recording element 84 is an electric heat conversion element (heat generation resistance element) made of a tantalum nitride silicon 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 foams the ink in the pressure chamber 85 by applying a drive pulse to generate heat. The ink in the pressure chamber 85 is ejected from the ejection port 86 by utilizing the foaming energy. Further, in the present embodiment, the temperature detection element 91 is connected to the wiring 93 by a thin film resistor made of titanium, a titanium nitride laminated film or the like, a conductive plug 98 such as tungsten, or the like. An interlayer insulating film 94, a protective film 95, and a cavitation resistant film 96 are formed on the recording element substrate 80a. Further, the recording element substrate 80a is provided with a discharge port forming portion 97 for forming the discharge port 86. In the recording element substrate 80a, the recording element 84 is formed on the temperature detecting element 91 formed on the interlayer insulating film 94 via the protective film 95.

The temperature of the recording element 84 mounted on the recording element substrate 80a is detected by the temperature detecting element 91. Then, the detected temperature is acquired by using the print controller 202, the head I / F 206 connected to the recording head 8, and the RAM 204. Here, the head I / F 206 includes a signal generation unit 211 that generates various signals for transmission to the recording element substrate 80a (see FIG. 2). Also. The head I / F 206 includes an extraction unit 212 for extracting the determination result signal RSLT output from the determination result output unit 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 recorded data signal DATA, a heat enable signal HE, and a discharge inspection threshold signal Dds. The discharge inspection threshold signal Dds can set a threshold value for a group of recording elements in which a plurality of recording elements mounted on the recording head 8 are divided into a plurality of groups including a plurality of recording elements located in the vicinity of each other. The set value can be changed in one column cycle. In the following description, the discharge inspection threshold voltage (Th) can be set for each group.

FIG. 10 is a diagram illustrating a method of determining an 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 the temperature. FIG. 10B is a graph showing the change in temperature detected by the temperature detecting element 91 when the ink is ejected. FIG. 10 (c) is a graph showing a change in the temperature change value based on the temperature change in FIG. 10 (b).

The recording element 84 generates heat when the drive pulse P of FIG. 10A is applied, and the ink is ejected from the ejection port 86 by the foaming energy of the ink. At this time, when the ink is normally ejected, the temperature detected by the temperature detecting element 91 changes as shown by the curve La shown by the solid line in FIG. 10 (b), and the ink is ejected due to non-ejection or the like. When a defect occurs, the temperature changes as shown by the curve Lb shown by the dotted line in FIG. 10 (b). When the ink is normally ejected, a part of the ink droplets ejected from the ejection port 86 falls on the upper part 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 sharply, and as a result, the detection temperature of the temperature detecting element 91 also drops sharply, as shown in the curve La. On the other hand, when ink ejection failure occurs, cooling due to such dropping of a part of ink droplets does not occur, so that the detection temperature of the temperature detecting element 91 gradually decreases as shown in the curve Lb.

FIG. 10C is an explanatory diagram of the temperature change value obtained by differentiating the temperature changes of the curves La and Lb. Then, 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. 10A is compared with the predetermined threshold value Th. In FIG. 10 (c), the temperature change value indicated by the solid curve LA is the differential value of the curve La, and the temperature change value indicated by the dotted curve LB is the 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 value Th, but the temperature change value of the curve LB does not exceed the threshold value Th.

Here, the recording element substrate 80a provided on 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 the determination result signal RSLT (FIG. 2). 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 the threshold value Th. ..

Therefore, when the threshold value Th is exceeded as in the curve LA, it appears in the determination result signal RSLT that the threshold value is exceeded. This determination result signal RSLT is extracted by the extraction unit 212, stored in the RAM 204, and used for determining the quality of the ink ejection state in the recording head 8 described later. As described above, in the present embodiment, the ink ejection state of each nozzle is detected depending on whether or not the differential value of the detected temperature of the temperature detecting element 91 exceeds the threshold value Th.

The process of detecting the ink ejection state in the nozzle based on the detection result of the temperature detecting element 91 is executed by, for example, the print controller 202. That is, in the present embodiment, the recording element substrate 80a, the print controller 202, the head I / F206, and the like function as detection units for detecting the ink ejection state in the nozzles.

The method for detecting the ink ejection state in the nozzle is not limited to the above-mentioned method, 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. In this method, an optical scan unit having a light emitting unit and a light receiving unit is used. The optical scan unit is scanned so that the optical axis formed between the light emitting unit and the light receiving unit passes through the flight path of the ejected ink, and when the ink is ejected, the light from the light emitting portion is emitted. It is blocked and the amount of light received by the light receiving unit decreases. By detecting this decrease in the amount of received light, the ink ejection state in the nozzle is detected.

(Removal of concentrated ink)
FIG. 11 is a schematic view showing a method of removing the concentrated ink generated in the vicinity of the ejection port, and shows the difference between the ink circulation and the removal of the concentrated ink by the preliminary ejection. In FIG. 11, it is shown that the darker the black color, the higher the ink density. Further, the concentrated ink is an ink in which the liquid component evaporates to thicken the ink, that is, an ink in which the solid content concentration in the ink is increased. 11 (a) to 11 (c) show a case where concentrated ink is removed by circulation of ink. FIG. 11 (a) shows a state in which concentrated ink is generated in the vicinity of the ejection port, FIG. 11 (b) shows a state in which concentrated ink has begun to be removed by circulation, and FIG. 11 (c) shows a state after the start of circulation. Indicates a steady state after a certain period of time. Further, FIGS. 11 (d) to 11 (f) show a case where the concentrated ink is removed by preliminary ejection. FIG. 11 (d) shows a state in which concentrated ink is generated in the vicinity of the ejection port, FIG. 11 (e) shows a state in which concentrated ink has begun to be removed by preliminary ejection, and FIG. 11 (f) shows a plurality of times. Indicates a state in which the concentrated ink has been removed by the preliminary ejection of.

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 ink is concentrated due to the evaporation of the liquid component in the ink from the surface of the ink located in 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 discharge port 86 and the foam chamber (pressure chamber 85), and the concentrated components are concentrated throughout the circulation system. Is unlikely to happen.

However, when ink circulation is started in a state where ink concentration has progressed (see FIG. 11A), the concentrated components accumulated in the ejection port 86 and the pressure chamber 85 are downstream of the ink flow due to the circulating ink. It flows to the side (see FIG. 11B). However, even if the ink circulation is continued, the concentrated component continues to remain in a part of the ejection port 86 (see FIG. 11C), and the concentrated ink cannot be completely removed. Further, the concentrated component mixes with the ink in the circulatory system and its concentration decreases, but the concentrated component spreads throughout the circulatory system, and the ink is concentrated in the entire circulatory system.

On the other hand, when the concentrated component is discharged from the discharge port 86 by preliminary ejection when the ink is not circulated, the concentrated component is discharged from the discharge port 86, so that the concentrated component remains and circulates in the discharge port 86. Ink concentration in the entire system is less likely to occur.

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

FIG. 12A is a flowchart showing the detailed processing contents of the recording process. When the recording process is started, first, the ink circulation 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 the head I / F 206. Next, recording on the recording medium is started (S1204). In S1204, the print controller 202 controls the head I / F 206, the transfer control unit 207, and the head carriage control unit 208 to perform recording on the transferred recording medium. After that, it is determined whether or not the recording on the recording medium is completed (S1206), and when it is determined that the recording is completed, the ink circulation is stopped (S1208) and the recording process is terminated.

(Recovery process)
Further, in the recording device 1, when the power is turned on, the ink ejection state of the recording head 8 is satisfactorily measured at a predetermined timing such as after the printing instruction is input and before the recording process is executed. Recovery processing is performed to maintain and recover. More specifically, in the present embodiment, the recovery process for eliminating the ink ejection failure due to the ink density is executed. Specifically, at a predetermined timing, the main controller 101 instructs the print controller 202 to execute the recovery process. Then, the print controller 202 executes the recovery process. As described above, in the present embodiment, the main controller 101 and the print controller 202 function as a control unit or a control device that controls to execute the recovery process.

FIG. 12B is a flowchart showing the detailed processing contents of the recovery processing. Ink circulation is not performed in this recovery process. Further, in order to determine the timing of the end of the recovery process, the detection result of the detection process for detecting the ink ejection state in the nozzle described above is used. It should be noted that such recovery processing is executed for each ink color. When the recovery process is started, first, a detection process accompanied by an ink ejection operation is executed (S1210). That is, the ink ejection state of each nozzle is detected by the above-mentioned detection process. Next, based on the detection result in this detection process, it is determined whether or not 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. As a basic idea of this determination method, for example, when the number of non-ejection nozzles is equal to or less than the first number determined by a predetermined condition, it is determined that the ink ejection state of the recording head 8 is good. Will be done. On the other hand, when the number of non-ejection nozzles is larger than the first number, it is determined that the ink ejection state of the recording head 8 is not good.

If it is determined that the condition is not good in S1212, the process returns to S1210 and the detection process is executed again. Further, in S1212, if it is determined to be good, the recovery process is terminated. As described above, in this recovery process, the detection process and the determination based on the detection result by the detection process are repeatedly executed until the ink ejection state of the recording head 8 is determined to be good.

Here, the action when the detection process is continued with respect to the state where the concentrated ink blocks the ejection port will be described. When the concentrated ink blocks the ejection port and the ink cannot be ejected, the ejection failure state continues for a while after the start of the detection operation due to the thickening of the ink in the vicinity of the ejection port. The change in the detection temperature at this time causes the detection temperature to gradually decrease as shown by the curve Lb in FIG. 10 (b).

When the ejection operation by the detection process is repeatedly executed, the ink is gradually ejected, and then the amount of the ejected ink gradually increases. This is because the thickening of the ink in the vicinity of the ejection port is gradually eliminated by the ejection of the ink, and the ink is easily ejected from the ejection port accordingly. When the thickening of the ink near the ejection port is eliminated, that is, when the removal of the concentrated ink near the ejection port is completed, the change in the detection temperature sharply decreases as shown by the curve La in FIG. 10 (b). Will be.

As a result, by ejecting the ink without circulating the ink, the concentrated component (concentrated ink) in the vicinity of the ejection port does not flow to the downstream side. Further, by continuing the detection operation until the ink ejection state of the recording head 8 becomes good, the concentrated ink can be reliably removed from the recording head.

In the recovery process, a process for maintaining and recovering the ink ejection state of the recording head 8 is performed while performing a detection process involving ink ejection as a process of detecting the ink ejection state of each nozzle. There is. Therefore, in each nozzle, while the ink ejection state is detected, processing for maintaining and recovering the ejection state satisfactorily is performed. Therefore, the time required for the recovery process is relatively short. That is, the time required for the recovery process can be shortened as compared with a known technique of sequentially executing the process of detecting the ink ejection state and the process of maintaining and recovering the ink ejection state in a good manner.

(Method for Determining Ink Discharge State in Recording Head 8)
In the recovery process, there are three determination methods for determining whether or not the ink ejection state of the recording head 8 is good, for example, the following first determination method, second determination method, and third determination method. A determination method can be used.

<First judgment 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 in which the ink cannot be ejected normally, that is, the ink is not ejected. For example, as the recording head 8, 15 chips corresponding to the recording element substrate 80a are arranged in series, and 1024 nozzles capable of ejecting 5 colors of ink are formed for each ink color on each chip. Imagine a head. The five color inks are black (K1, K2), cyan (C), magenta (M), and yellow (Y) inks. The nozzles each include a recording element 84, a pressure chamber 85, and a discharge port 86. The total number of nozzles in the recording head 8 is 76,800 (5 × 1024 × 15).

FIG. 13 is a table in which the threshold value used in the first determination method is set for each ink color, (a) is a table in which the number of non-ejection nozzles (first nozzle) is set as the threshold value, and (b) is a table. It is a table which made the ratio of non-ejection nozzles a threshold value. The threshold values shown in FIGS. 13A and 13B are merely examples, and can be appropriately changed according to the configuration of the recording head 8. Moreover, such a threshold value is obtained experimentally, for example.

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

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

With black ink, when a nozzle ejection failure occurs, the change in the recorded image due to the ejection failure is likely to be noticeable. Therefore, for black ink, it is preferable to set the corresponding threshold value relatively small. Further, with yellow ink, when a nozzle ejection defect occurs, the change in the recorded image due to the ejection defect is 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. 13B, the ratio of the number of non-ejection 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 ratio of the detected non-ejection nozzles is equal to or less than the corresponding threshold value for all the ink colors, the recording head 8 determines that the nozzle ejection state is good. On the other hand, when the ratio of the detected non-ejection nozzles for at least one ink color exceeds the corresponding threshold value, the recording head 8 determines that the nozzle ejection state is not good.

Also in this case, the ratio of the total number of nozzles determined to be non-ejection nozzles for all ink colors to the total number of nozzles is also set as a threshold value. Even if the ink processing is below the threshold value, when the ratio of the total number of all ink colors of the nozzles determined to be non-ejection nozzles exceeds the threshold value, the print controller 202 ejects the nozzles at the recording head 8. Judge that the condition is not good. On the other hand, when the ratio is equal to or less than the threshold value, the print controller 202 determines that the nozzle ejection state of the recording head 8 is good.

<Second judgment method>
In the second determination method, the quality of the ejection state of the nozzles of the entire recording head 8 is determined based on the number of non-ejection nozzles in the recording head 8 in units of chips (recording element substrate 80a). Similar to the case of the first determination method described above, as the recording head 8, 15 chips corresponding to the recording element substrate 80a are arranged in series, and the nozzle capable of ejecting 5 colors of ink to each chip is the ink color. It is assumed that 1024 recording heads are formed for each recording head.

FIG. 14 is a table in which the threshold value used in the second determination method is set for each chip, (a) is a table in which the total number of non-ejection nozzles generated in the chip is used as the threshold value, and (b) is a table in which the total number of non-ejection nozzles generated in the chip is used as the threshold value. It is a table in which the number of non-ejection nozzles set for each ink color in 1 is set as a threshold value. The threshold values shown in FIGS. 14A and 14B are merely examples, and can be appropriately changed according to the configuration of the recording head 8. Moreover, such a threshold value is obtained experimentally, for example.

In the second determination method, as shown in FIG. 14A, the total number of non-ejection nozzles generated in each of the five color inks is preset as a threshold value for each of the total of 15 chips from the 0th to the 14th. Keep it. Then, for each chip, the total number of non-ejection nozzles of each of the detected five colors of ink is compared with the corresponding threshold value. When the total number of non-ejection nozzles detected in all the chips is equal to or less than the corresponding threshold value, the recording head 8 determines that the nozzle ejection state is good. On the other hand, when the total number of non-ejection nozzles detected in at least one chip exceeds the corresponding threshold value, the recording head 8 determines that the nozzle ejection state is not good. In the chip located at the center in the arrangement direction, the change in the recorded image is easily noticeable when the nozzle ejection failure occurs, so it is preferable to set the corresponding threshold value relatively small. Further, with the chips located on both end sides in the arrangement direction, the change in the recorded image is not noticeable when the nozzle ejection failure occurs, so that the corresponding threshold value can be set relatively large.

Further, in the second determination method, as shown in FIG. 14B, the number of non-ejection nozzles may be set as a threshold value for each ink color in each chip. In this case, when the number of non-ejection nozzles detected for each ink color in all the chips is equal to or less than the corresponding threshold value, the recording head 8 determines that the nozzle ejection state is good. When one of the small number of non-ejection nozzles detected for each ink color 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.

In the second determination method, the determination is made based on the number of non-ejection nozzles, but as in the first determination method, the determination is based on the ratio of the number of non-ejection nozzles to the total number of nozzles for each ink color. You may try to do it.

<Third judgment method>
In the third determination method, the nozzles stored in advance as non-ejection 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-ejection nozzles.

The cause of the non-ejection state of ink that can be recovered by the circulation of ink and the preliminary ejection is mainly the sticking of concentrated ink to the ejection port or the like. However, with respect to the nozzles determined to be non-ejection nozzles in the previously executed detection process (hereinafter referred to as "non-ejection determination nozzles"), depending on the factors, ink circulation or preliminary ejection may cause ink. It may not be possible to recover the discharge state satisfactorily. The above factors include, for example, nozzle failure, clogging of the discharge port due to foreign matter such as dust, and the like.

In the third determination method, a non-ejection determination nozzle (second nozzle) whose ink ejection state cannot be recovered only by ink circulation or preliminary ejection is stored, and such a non-ejection determination nozzle is used for the ink of the entire recording head 8. Exclude from the target for judging the quality of the discharge state. As a result, it is possible to reduce the time during which recording cannot be performed by the recovery process. The controller unit 100 or the print engine unit 200 has a function for storing in the ROM 107 a non-ejection nozzle 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, the number of nozzles for each ink color is 10 (nozzles numbers 0 to 9) for easy understanding. Further, the threshold value for each ink color is set to 15% as the ratio of the number of non-ejection nozzles to the total number of nozzles for each ink color.

It is assumed that the detection process has obtained the detection result as shown in FIG. In this detection result, with respect to the nozzle for ejecting the black ink K1, two nozzles having nozzle numbers "2" and "6" are detected as non-ejection nozzles. The nozzle number "2" is stored in advance as a non-ejection determination nozzle. Therefore, in the determination based on this detection result, the number of nozzles to be determined is 9 which is obtained by subtracting 1 non-ejection determination nozzle from the total number of nozzles of 10. Further, the number of non-ejection nozzles to be determined is one obtained by subtracting one non-ejection determination nozzle from two actually detected non-ejection nozzles. As a result, the proportion of non-ejection nozzles becomes 11%, which is equal to or less than the corresponding threshold value of 15%. As a result, it is determined that the ink ejection state of the nozzle for ejecting the black ink K1 is good. It should be noted that the nozzles for ejecting cyan ink C, magenta ink M, and yellow ink Y are also determined to be in good ink ejection state.

Further, regarding the nozzle that ejects the black ink K2, the nozzle number "4" is stored as the non-ejection determination nozzle, but in the detection result this time, the two nozzles of the nozzle numbers "8" and "9" are stored. It is detected as a non-ejection nozzle. Therefore, the number of nozzles to be determined is 9, and the number of non-ejection nozzles to be determined is 2. As a result, the proportion of non-ejection nozzles becomes 22%, which exceeds the corresponding threshold value of 15%. As a result, it is determined that the ink ejection state of the nozzle for ejecting the black ink K2 is not good.

In this way, the quality of the ink ejection state is determined for each ink color, and the detection result as shown in FIG. 15, that is, when it is determined that the ink ejection state is not good in at least one ink color nozzle, is recorded. It is determined that the ink ejection state of the head 8 is not good. Further, when it is determined that the ink ejection state is good in all the ink color nozzles, it is determined that the ink ejection state in the recording head 8 is good.

As described above, in the recording device 1 according to the first embodiment, the ink ejection state is detected based on the temperature change at the time of ink ejection from the nozzle. Then, in the recovery process for maintaining and recovering the ink ejection state of the recording head 8 satisfactorily, the ink ejection operation by the detection process for detecting the ink ejection state of the nozzle may cause concentration that may cause ink non-ejection. I tried to remove the ink.

As a result, in the recording device 1, the detection process for detecting the ink ejection state at the nozzle and the recovery operation for recovering the ink ejection state at the recording head 8 are executed in parallel. Therefore, the time required for detecting the ejection state of the nozzle, performing the recovery operation, and determining that the ejection state of the nozzle is good, that is, the time required for the recovery process can be shortened.

(Second Embodiment)
Next, the inkjet recording apparatus according to the second embodiment of the present invention will be described with reference to FIGS. 16A and 16B. In the following description, with respect to the configuration that is the same as or equivalent to the above-described first embodiment, the same reference numerals as those used in the first embodiment will be used, and detailed description thereof will be omitted.

This second embodiment is different from the above-described first embodiment in that the recovery process stops the execution of the detection process at a predetermined timing and ends the recovery process.

FIG. 16 is a flowchart showing a detailed processing content of the recovery processing executed by the recording device according to the second embodiment. FIG. 16A is a flowchart when a predetermined timing is set based on the elapsed time after the recovery process is started. FIG. 16B is a flowchart when a predetermined timing is set based on the number of detection processes.

When the recovery process is started, first, the time count is started (S1602). That is, in S1602, the print controller 202 starts counting the time by 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). Then, based on the detection result of this detection process, it is determined whether or not 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, and thus the description thereof will be omitted.

If it is determined to be good in S1606, this recovery process is terminated. Further, in S1606, if it is determined that the condition is not good, it is determined whether or not a predetermined time has elapsed since the recovery process was started (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, in S1608, when it is determined that the predetermined time has elapsed, this recovery process is terminated.

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 detections in which the detection process is executed. Specifically, when the recovery process is started, the print controller 202 first sets the 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). After that, based on the detection result of the detection process, it is determined whether or not the ink ejection state of the recording head 8 is good (S1614). The specific processing contents of S1610 and S1614 are the same as those of S1210 and S1212 described above, and thus the description thereof will be omitted.

If it is determined to be good in S1614, this recovery process is terminated. Further, in S1614, if it is determined that the value is not good, it is determined whether or not 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), the process returns to S1612, and the detection process is executed again. Further, in S1616, when it is determined that the predetermined value has been reached, this recovery process is terminated.

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

As described above, in the recording device 1 according to the second embodiment, the recovery process is terminated at a predetermined timing after the start of the recovery process. As a result, in the recording device 1, in addition to the effects of the first embodiment, when the ink ejection state of the recording head 8 is not restored due to preliminary ejection or ink circulation, for example, due to a failure of the recording element 84. , You will be able to finish the recovery process.

(Third Embodiment)
Next, the inkjet recording apparatus according to the third embodiment of the present invention will be described with reference to FIGS. 17 (a) and 17 (b). In the following description, with respect to the configuration that is the same as or equivalent to the above-described first embodiment, the same reference numerals as those used in the first embodiment will be used, and detailed description thereof will be omitted.

The third embodiment is different from the first and second embodiments described above in the following points. That is, in the recovery process, if the determination that the ink ejection state in the recording head 8 is not good is continued based on the detection result of the detection process, the detection process is performed while executing the ink circulation at a predetermined timing. I did.

FIG. 17A is a flowchart showing a detailed processing content of the recovery processing executed by the recording device according to the third embodiment. When the recovery process is started, first, the time count is started (S1702). Next, a detection process for detecting the ink ejection state of the nozzle is executed (S1704). Then, based on the detection result of this detection process, it is determined whether or not the ink ejection state of the recording head 8 is good (S1706). Since the specific processing contents of S1702, S1704, and S1706 are the same as those of S1602, S1210, and S1212 described above, the description thereof will be omitted.

If it is determined to be good in S1706, this recovery process is terminated. Further, if it is determined in S1706 that the condition is not good, it is determined whether or not a predetermined time has elapsed since the recovery process was started (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, in S1708, when it is determined that the predetermined time has elapsed, the 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 the ink in the circulation path.

Next, a detection process for detecting the ink ejection state of the nozzle is executed (S1712), and based on the detection result of this detection process, it is determined whether or not the ink ejection state of the recording head 8 is good (S1714). .. Since the specific processing contents of S1712 and S1714 are the same as those of S1210 and 1212 described above, the description thereof will be omitted. If it is determined in S1714 that it is not good, the process returns to S1712 and the detection process is executed again. Further, in S1714, if it is determined to be good, the circulation of the ink is stopped (S1716), and this recovery process is terminated. 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.

If it is determined in S1714 that the recovery process is not good, the recovery process is based on the elapsed time after the start of the recovery process or the number of detections in which the detection process is executed in S1712, as in the second embodiment. The recovery process may be terminated.

Further, in this recovery process, the ink circulation is started at the timing when a predetermined time elapses after the start of the recovery process, but the present invention is not limited to this. As in the second embodiment, the ink circulation may be started at the timing when the number of detections in which the detection process in S1704 is executed reaches a predetermined value (predetermined number of times). Hereinafter, description will be made with reference to FIG. 17 (b). FIG. 17B is a flowchart showing a detailed processing content of a modified example of the recovery processing executed by the recording device according to the third embodiment. Note that, in FIG. 17B, detailed description of the same processing as in FIG. 17A will be omitted by using the same step number. In the recovery process of FIG. 17B, when the recovery process is started, the variable n representing the number of detections by the detection process is set to “1” (S1722). Then, in S1706, if it is determined that the ink ejection state is not good, it is determined whether or not n has reached a predetermined value (S1724), and if it is determined that n has reached a predetermined value, S1710 is determined. move on. If it is determined that the variable n has not reached a predetermined value, the variable n is incremented (S1726) and the process proceeds to S1704.

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

(Fourth Embodiment)
Next, the inkjet recording apparatus according to the fourth embodiment of the present invention will be described with reference to FIG. In the following description, with respect to the configuration that is the same as or equivalent to the above-described first embodiment, the same reference numerals as those used in the first embodiment will be used, and detailed description thereof will be omitted.

In the fourth embodiment, in the recovery process, the first embodiment, the second embodiment, and the third embodiment described above are executed in that the detection process is executed while circulating the ink only for a specific ink. It is different from the form.

Here, the ink has a difference in viscosity increase when the liquid component evaporates depending on the ink type. For example, black ink tends to thicken when the liquid component evaporates, as compared with color inks such as cyan ink, magenta ink, and yellow ink. Therefore, with respect to such black ink, concentrated ink is more likely to be generated and it is difficult to remove the generated concentrated ink as compared with color ink. Therefore, in the present embodiment, an ink that is easier to thicken than other inks is set in advance, and for the set ink, the effect of removing the concentrated ink is enhanced and the detection process is executed. I tried to do it. In addition, since the recovery process according to the first embodiment is executed for the ink that has not been set, in the following description, only the recovery process executed for the set ink will be described in detail. That is, in the present embodiment, when the start of the recovery process is instructed, the recovery process for the set ink and the recovery process for the unset ink according to the first embodiment described below are performed in parallel. It will be executed.

FIG. 18 is a flowchart showing a detailed processing content of the recovery processing for the set ink executed by the recording device 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 as the ink that easily thickens in the ROM 203. In the present embodiment, the preset ink that easily thickens is stored in the ROM 203, but when the recovery process is started, the print controller 202 provides information about the ink that easily thickens. It suffices if it can be obtained.

Next, a detection process for detecting the ink ejection state of the nozzle is executed (S1804), and based on the detection result of this detection process, it is determined whether or not the ink ejection state of the recording head 8 is good (S1806). .. The specific processing contents of S1804 and S1806 are the same as those of 1210 and S1212 described above, respectively, and thus the description thereof will be omitted.

If it is determined in S1806 that it is not good, the process returns to S1804 and the detection process is executed again. Further, in S1806, when it is determined to be good, the circulation of the ink is stopped (S1808), and this recovery process is terminated. 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 stored as the ink that easily thickens in the ROM 203.

As described above, in the recording device 1 according to the fourth embodiment, the detection process is executed while circulating the ink for the ink that tends to thicken due to the evaporation of the liquid component. As a result, the recording device 1 can enhance the effect of removing the concentrated ink with respect to the ink that tends to thicken in the recovery process.

(Fifth Embodiment)
Next, the inkjet recording apparatus according to the fifth embodiment of the present invention will be described with reference to FIG. In the following description, with respect to the configuration that is the same as or equivalent to the above-described first embodiment, the same reference numerals as those used in the first embodiment will be used, and detailed description thereof will be omitted.

In the fifth embodiment, the first embodiment, the second embodiment, and the third embodiment described above are changed in that the presence or absence of ink circulation is changed during the detection process according to the ink density information in the recovery process. It is different from the embodiment and the fourth embodiment. That is, the recording device 1 according to the present embodiment is designed to eliminate the ink ejection failure due to the increase in the ink density in the circulation path due to the recording operation by the recovery process. That is, in the present embodiment, the recovery process is executed after the recording process.

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

_{Here, the print controller 202 acquires the density N X + 1} of the ink in the circulation path for each recording operation. Then, the acquired value is overwritten and saved in, for example, ROM 203 as the density Nc of the ink in the circulation path. The concentration N _{X + 1} is obtained by using the following equation (1).
N _{X + 1} = (N _x × (Jn-In)) / (Jn-In-V) ... (1)

N _{X + 1} is the current density of the ink. N _x is the density of the ink before the recording operation. For N _{X + 1} and N _X , if the concentration is 5% by weight, the value is 0.05. Jn is the amount of ink in the circulation path before the recording operation, and is, 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 acquired based on the recorded data. V is the amount of ink evaporated from the circulation path and is preset.

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

When it is determined in S1904 that the density Nc exceeds a predetermined density, ink circulation is started (S1906). That is, when the concentration Nc exceeds a predetermined concentration, the liquid components in the ink in the circulation path are evaporated, and the thickening cannot be efficiently eliminated only by the ejection operation. Therefore, the ink is circulated. Is done. After that, a detection process for detecting the ink ejection state of the nozzle is executed (S1908), and based on the detection result of this detection process, it is determined whether or not the ink ejection state of the recording head 8 is good (S1910). Since the specific processing contents of S1908 and S1910 are the same as those of S1210 and 1212 described above, the description thereof will be omitted.

Here, the ink in the circulation path is reduced by the ink ejection operation 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, the ink is replenished from the main tank 141 under the control of the ink supply control unit 209. Therefore, the viscosity of the ink in the circulation path is reduced, and the ink ejection state is improved. If it is determined in S1910 that it is not good, the process returns to S1908 and the detection process is executed again. Further, in S1910, if it is determined to be good, the circulation of the ink is stopped (S1912), and this recovery process is terminated.

On the other hand, in S1904, when it is determined that the density Nc is equal to or less than a predetermined density, a detection process for detecting the ink ejection state of the nozzle is executed (S1914). Then, based on the detection result of this detection process, it is determined whether or not the ink ejection state of the recording head 8 is good (S1916). Since the specific processing contents of S1914 and S1916 are the same as those of S1210 and 1212 described above, the description thereof will be omitted. If it is determined in S1916 that it is not good, the process returns to S1914 and the detection process is executed again. Further, in S1916, if it is determined that the condition is not good, the recovery process is terminated.

As described above, in the recording device 1 according to the fifth embodiment, when the thickened ink after the recording process exceeds a predetermined density, the detection process is performed while circulating the ink. As a result, the recording device 1 can efficiently improve the ink ejection state for the ink exceeding the predetermined density.

(Other embodiments)
The above-described embodiment may be modified as shown in (1) to (4) below.

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

Along 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 wiping operation is performed by the blade wiper unit 171 while the adhered ink is thickened, the thickened ink is pushed into the ejection port 86, and the concentrated ink is located in the vicinity of the ejection port 86. The recovery process according to the present embodiment is applied to such a state. That is, by performing the detection process accompanied by the ejection of the ink without circulating the ink, the thickening ink (concentrated ink) pushed into the ejection port 86 is suppressed from flowing to the downstream side of the circulation path, while being suppressed. The thickening ink can be removed.

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

(2) The present invention supplies a program that realizes one or more functions of the above embodiment to a system or a device via a network or a storage medium, and one or more processors in the computer of the system or the device execute the program. It can also be realized by the process of reading and executing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions. Although not particularly described in the above-described embodiment, the recording device 1 may have a configuration in which the recovery process in each of the above-described embodiments can be selected. Further, although not particularly described in the above embodiment, the controller unit 100 and the print engine unit 200 may be mounted on the recording device 1, and the functions thereof may be mounted on the recording device 1 as an external device connected to the recording device 1. May be executed.

(3) In the above embodiment, the recording device 1 records using five types of inks of different colors, but the present invention is not limited to this. That is, recording may be performed using one or more types of inks. Further, the type of ink is not limited to the difference in color, and ink having different characteristics may be used. Further, in the above embodiment, the ink is circulated when a predetermined condition such as a timing when a predetermined time elapses, a timing for executing a recovery process for the set ink or an ink exceeding the predetermined density is satisfied. However, it is not limited to this. Predetermined conditions for circulating ink may be settable.

(4) The above-described embodiment and the various forms shown in the above-mentioned (1) to (3) may be appropriately combined.

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

Claims (21)

A recording means equipped with a plurality of nozzles that eject ink by the heat generated by the recording element, and
A circulation means capable of executing ink circulation in the circulation path including the recording means, and a circulation means.
It is an inkjet recording device equipped with
A detection means for detecting the ink ejection state in the nozzle based on the detection temperature of the nozzle when the ink is ejected, and
During the recovery process for eliminating the ink ejection failure caused by the ink density, the recording element is heated to generate heat and the ink is ejected from the nozzle without circulating the ink by the circulating means, and the detection means causes the nozzle to eject the ink. A control means that controls to detect the ink ejection state, and
An inkjet recording apparatus characterized by having. The inkjet recording apparatus according to claim 1, wherein the detection means detects based on a temperature change value according to a change in the detection temperature. Further, it has a determination means for determining the quality of the ink ejection state in the recording means based on the number of the first nozzles in which the detection means has detected that the ink is not ejected normally.
The inkjet recording apparatus according to claim 1 or 2, wherein the control means repeats detection by the detection means until the determination means determines that the ink ejection state in the recording means is good. .. The inkjet recording apparatus according to claim 3, wherein the determination means determines based on the ratio of the number of the first nozzles to the total number of nozzles. The recording means ejects a plurality of types of ink and ejects a plurality of types of ink.
The inkjet recording apparatus according to claim 3 or 4, wherein the determination means determines the ink ejection state for each ink type, and determines the ink ejection state in the recording means based on the determination. The recording means includes a plurality of chips in which nozzles for ejecting ink are arranged.
The inkjet recording apparatus according to claim 3 or 4, wherein the determination means determines the ink ejection state of each of the chips, and determines the ink ejection state of the recording means based on the determination. .. The recording means ejects a plurality of types of ink on the chip, and the recording means ejects a plurality of types of ink.
The determination 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 claim 6. The determination means determines the ink ejection state of the chip based on a threshold value corresponding to the position where the chips are arranged, and the threshold value is set low at the central portion in the arrangement direction of the chips, and the arrangement is performed. The inkjet recording apparatus according to claim 6 or 7, wherein the ink jet recording apparatus is set higher on the end side in the direction. The determination means makes a determination based on a threshold value according to the ink type, and the threshold value is set low for black ink and high for yellow ink, according to any one of claims 3 to 8. The inkjet recording apparatus according to the above. The determination means is based on the ratio of the number of the first nozzles to the number of nozzles obtained by subtracting the number of the second nozzles from which the ink is not normally ejected from the total number of nozzles ejecting the ink. The inkjet recording apparatus according to claim 3, wherein the determination is made. In the recovery process, any one of claims 3 to 10, wherein 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 apparatus according to item 1. The inkjet recording apparatus according to claim 11, wherein the predetermined condition is a timing at which a predetermined time has elapsed after the start of the recovery process. The inkjet recording apparatus according to claim 11, wherein the predetermined condition is a timing at which the number of detections detected by the detection means exceeds the predetermined number of times. The inkjet recording apparatus according to claim 11, wherein the predetermined condition is a timing for executing the recovery process on the set ink. The inkjet recording apparatus according to claim 14, wherein the set ink is an ink that easily thickens due to evaporation of a liquid component. The inkjet recording apparatus according to claim 11, wherein the predetermined condition is a timing for executing the recovery process for ink exceeding a predetermined density. According to any one of claims 3 to 16, 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 apparatus described. Further having a wiping means for performing a wiping operation with respect to the recording means,
The inkjet recording apparatus according to any one of claims 1 to 17, wherein the recovery process is executed after the wiping operation. A recording means equipped with a plurality of nozzles that eject ink by the heat generated by the recording element, and
A circulation means capable of executing ink circulation in the circulation path including the recording means, and a circulation means.
A detection means for detecting the ink ejection state in the nozzle based on the detection temperature of the nozzle when the ink is ejected, and
A control device that controls an inkjet recording device equipped with the above to execute a recovery process for eliminating ink ejection defects caused by ink density.
A control device characterized in that the recording element is generated to generate heat and ink is ejected from a nozzle without circulating ink by the circulation means, and the detection means is controlled to detect an ink ejection state in the nozzle. The control device according to claim 19, wherein when a predetermined condition is satisfied, the ink is circulated by the circulation means and the detection is controlled by the detection means. A program for operating a computer as the control device according to claim 19 or 20.

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