JP7265145B2 - Inkjet recording device - Google Patents

Description

The present invention relates to an inkjet recording apparatus, and more particularly to a technique for cleaning an ink ejection surface of a recording head.

For example, there is an inkjet recording apparatus that records an image on a recording medium by ejecting ink from nozzles of a recording head onto a recording medium such as paper. The ink column ejected from the nozzles of the recording head is divided into main droplets and very small droplets (that is, mist). Since this mist is greatly affected by air resistance and transport wind, it adheres to the nozzle surface of the recording head. If this adhered mist is water-based ink, it gradually dries and adheres strongly to the nozzle surface. It is difficult to completely remove the mist by the cleaning method of wiping the nozzle surface several times.

Therefore, in Patent Document 1 below, a cleaning liquid supply unit having a cleaning liquid supply surface having a cleaning liquid supply port for supplying the cleaning liquid is provided upstream of the nozzle surface of the recording head in the wiping movement direction of the wiper, and ink is supplied from the nozzles. An inkjet recording apparatus has been proposed that has a mechanism for wiping the nozzle surface with a wiper to which cleaning liquid from a cleaning liquid supply port is applied after purging. According to this mechanism, mist adhering to the nozzle surface is removed by wiping the nozzle surface with a wiper soaked with cleaning liquid.

JP 2018-089829 A

However, in the inkjet recording apparatus described in JP-A-2003-130002, although the mist adhering to the nozzle surface is removed by a mechanism for wiping the nozzle surface with a wiper soaked with a cleaning liquid, paper contamination due to an unknown cause may occur. There is a problem that an image defect may occur.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the occurrence of image defects due to paper stains.

Through intensive research by the inventors, the cause and effect of the occurrence of image defects due to unexplained paper stains have been ascertained. For example, bubbles may be generated or air may enter the cleaning liquid in the tube connected to the cleaning liquid supply port. Since the cleaning liquid in the cleaning liquid supply port and the tube is supplied only in one direction, if there is air in the cleaning liquid supply port or the tube, the only way to eliminate the air is to push it out. In a normal head cleaning operation, since the amount of cleaning liquid discharged from the cleaning liquid supply port is small, the air bubbles cannot be completely expelled each time. Wiping the nozzle surface with the attached wiper leaves a tall bubble at the end of the wipe. It has been found that the height of the recording head and the paper during image formation is as narrow as 1.0 mm, for example, at its narrowest, so that the bubbles come into contact with the paper and cause image defects. Therefore, the inventors conceived of a configuration for controlling the operation of removing air bubbles in the cleaning liquid flow path by pushing out the cleaning liquid in the cleaning liquid flow path. Then, it was found that the control of the air bubble removal operation is effective. Further, the cleaning liquid flow path is composed of a vertical tubular member extending upward from the cleaning liquid supply portion and a horizontal tubular member connected to the upper end side of the vertical tubular member and extending in the horizontal direction. The control conditions under which air bubbles can be separated by , and the air bubble removal control can be suitably realized while suppressing the supply amount of the cleaning liquid were obtained from experimental data.

The present invention is an invention made based on the above findings, and an inkjet recording apparatus according to one aspect of the present invention includes a recording head including an ink ejection surface having ink ejection openings from which ink is ejected; a wiper member for wiping the ink ejection surface by moving in a predetermined wiping direction; and a cleaning liquid supply surface having a cleaning liquid supply port for supplying the cleaning liquid used for wiping the ink ejection surface by the wiper member. a cleaning liquid supply section provided on the upstream side in the wiping direction of the ink ejection surface; a cleaning liquid storage section for storing cleaning liquid; and a cleaning liquid flow for guiding the cleaning liquid from the cleaning liquid storage section to the cleaning liquid supply section. a driving unit for moving the cleaning liquid in the cleaning liquid flow path and applying power to push the cleaning liquid from the cleaning liquid supply port; and a cleaning operation for wiping the ink discharge surface by the wiper member using the cleaning liquid. the cleaning liquid channel includes a vertical tubular member having one end connected to the cleaning liquid supply section and extending upward from the one end to the other end of the cleaning liquid supply section; a horizontal tubular member connected to the upper end side of the tubular member and extending horizontally from one end to the other end thereof; By pushing out at least a part of the cleaning liquid from the cleaning liquid supply port, the operation of removing air bubbles from the cleaning liquid flow path is controlled.

According to the present invention, it is possible to reduce the occurrence of image defects due to paper stains.

1 is a schematic cross-sectional front view showing the configuration of an inkjet recording apparatus according to a first embodiment of the present invention; FIG. FIG. 10 is a diagram showing a state in which the conveying unit has moved to the lower maintenance position and the cleaning section has moved to a position directly below the recording section; 1 is a functional block diagram schematically showing the main internal configuration of an inkjet recording apparatus according to a first embodiment; FIG. (A) is a diagram showing a recording section and a conveying unit, and (B) is a diagram of the conveying unit and the recording section viewed from above. (A) is a partially broken side view showing a state in which the ink tray and wiper unit of the cleaning section are arranged below the recording section, and (B) is a view of the ink ejection surface of the recording head. FIG. 4 is a diagram schematically showing a cleaning liquid flow path for supplying cleaning liquid to one line head; 4A is a flow chart showing an example of processing performed by the inkjet recording apparatus according to the first embodiment, and FIG. (A) to (E) are partially cutaway side views for explaining the bubble removing operation performed before the cleaning operation. (A) to (E) are partially broken side views for explaining the cleaning operation. It is a figure which shows the result of the experimental data of a vertical tube bubble vent. It is a figure which shows the result of the experimental data of whole-system bubble removal. FIG. 5 is a functional block diagram schematically showing the main internal configuration of an inkjet recording apparatus according to a second embodiment;

An inkjet recording apparatus according to one embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional front view showing the configuration of an inkjet recording apparatus according to a first embodiment of the invention. FIG. 2 is a diagram showing a state in which the transport unit has moved to the lower maintenance position and the cleaning section has moved to the position directly below the recording section. The inkjet recording apparatus 1 is, for example, a multifunction machine having multiple functions such as a copy function, a printer function, a scanner function, and a facsimile function. It includes a reading section 5 , an image recording section 12 , a paper feeding section 14 , a paper conveying section 19 , a conveying unit 125 and a cleaning section 8 .

The operation unit 47 receives instructions such as image recording operation execution instructions from the operator regarding various operations and processes that can be performed by the inkjet recording apparatus 1 . The operation unit 47 includes a display unit 473 that displays operation guidance and the like for the operator. The display unit 473 is a touch panel, and the operator can operate the inkjet recording apparatus 1 by touching buttons and keys displayed on the screen.

A case where the inkjet recording apparatus 1 performs a document reading operation will be described. The document reading section 5 optically reads the image of the document fed by the document feeding section 6 or the document placed on the platen glass 161, and generates image data. Image data generated by the document reading unit 5 is stored in an image memory (not shown) or the like.

The document reading unit 5 includes a reading mechanism 163 having a light source irradiation unit and a CCD (Charge Coupled Device) sensor. An image is read from an original by receiving light with a CCD sensor.

A case where an image recording operation is performed by the inkjet recording apparatus 1 will be described. Based on document image data generated by a document reading operation, document image data stored in an image memory or the like, document image data received from a computer connected to a network, and the like, the image recording unit 12 reads the paper feed unit 14. , and an image is recorded on the paper P that is fed from and transported by the paper transport unit 19 .

The paper feed unit 14 includes a paper feed cassette 141 . A paper feed roller 145 is provided above the paper feed cassette 141 , and the paper P accommodated in the paper feed cassette 141 is delivered toward the transport path 190 by the paper feed roller 145 .

The paper feeding unit 14 also includes a manual feed tray 142 that is openable and closable on the wall surface of the apparatus main body 11 . The paper P set on the manual feed tray 142 is fed out toward the transport path 190 by the paper feed roller 146 .

The paper transport section 19 includes a transport path 190 for transporting the paper P from the paper feed section 14 toward the discharge tray 151 , a pair of transport rollers 191 and a pair of discharge rollers 192 provided at appropriate positions on the transport path 190 .

The paper P fed from the paper feeding unit 14 is transported through the transport path 190 by the pair of transport rollers 191 . The paper P on which an image has been recorded by the image recording unit 12 is discharged face up to the discharge tray 151 by the discharge roller pair 192 through the discharge conveying path 193 (part of the conveying path 190).

Further, the paper conveying section 19 has an offset mechanism (not shown) that shifts the paper P to be discharged to the discharge tray 151 in the paper width direction by moving the discharge roller pair 192 in the direction perpendicular to the paper conveying direction.

The image recording unit 12 records an image based on document image data on the paper P fed from the paper feeding unit 14 and transported along the transport path 190 . and an ink tank 122 .

The transport unit 125 includes a drive roller 125A, a driven roller 125B, a tension roller 127, and a transport belt 128. The transport belt 128 is an endless belt, and is stretched over a driving roller 125A, a driven roller 125B, and a tension roller 127. As shown in FIG. The drive roller 125A is a roller that is rotated counterclockwise by a motor (not shown). By rotating the drive roller 125A, the transport belt 128 runs counterclockwise, and the driven roller 125B and the tension roller 125A rotate. Roller 127 is driven to rotate counterclockwise.

The tension roller 127 is a roller for keeping the conveying belt 128 in an appropriate tension state. The attraction roller 126 is arranged to face the driven roller 125B while being in contact with the transport belt 128. By charging the transport belt 128, the sheet P fed from the paper feed unit 14 is electrostatically applied to the transport belt 128. It is meant to be adsorbed.

The recording unit 3 ejects ink droplets of four different colors (black, cyan, magenta, and yellow) onto the paper P conveyed by the paper conveying unit 19 to sequentially record images. The ink tank 122 is filled with ink corresponding to each color.

Specifically, the recording unit 3 has line heads 31, 32, 33, and 34 corresponding to black, cyan, magenta, and yellow, respectively. Therefore, the inkjet recording apparatus 1 is a line head type inkjet recording apparatus. The recording unit 3 also has a head frame 35 (see FIGS. 4A and 4B) that supports the line heads 31-34. The head frame 35 is supported by the device body 11 .

The lifting mechanism 129 supports the transport unit 125 from below and moves the transport unit 125 up and down with respect to the line heads 31-34. That is, the lifting mechanism 129 separates and approaches the transport unit 125 and the line heads 31 to 34 by moving the transport unit 125 relative to the line heads 31 to 34 . Specifically, the elevating mechanism 129 has a recording position (the position shown in FIG. 1) where printing by the recording unit 3 is possible, and a maintenance position (the position shown in FIG. ) to move the transport unit 125 between them.

FIG. 3 is a functional block diagram schematically showing the main internal configuration of the inkjet printing apparatus according to the first embodiment. The inkjet recording apparatus 1 includes a control unit 10, a document feeding section 6, a document reading section 5, an image recording section 12, a paper feeding section 14, a paper conveying section 19, an operating section 47, a driving mechanism 88, a conveying unit 125, and an elevating mechanism. 129 , cleaning liquid pump 130 and cleaning unit 8 . Components similar to those of the inkjet recording apparatus 1 shown in FIG.

The paper feeding section 14 and the paper conveying section 19 are provided with roller driving sections 14A and 19A, respectively. The roller drive units 14A and 19A are composed of motors, gears, drivers, etc., and the roller drive unit 14A functions as a drive source that imparts rotational driving force to the paper feed rollers 145 and 146. FIG. The roller drive unit 19A functions as a drive source that imparts a rotational drive force to the drive rollers of the transport roller pair 191 and the discharge roller pair 192 .

The control unit 10 includes a processor, RAM (Random Access Memory), ROM (Read Only Memory), and dedicated hardware circuits. The processor is, for example, a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or an MPU (Micro Processing Unit). The control unit 10 has a control section 100 .

The control unit 10 functions as a control section 100 as the processor operates according to a control program stored in a built-in non-volatile memory or the like. However, the control unit 100 and the like can also be configured by hardware circuits without relying on the operation according to the control program by the control unit 10 . Hereinafter, the same applies to each embodiment unless otherwise specified.

The control unit 100 controls the overall operation of the inkjet recording apparatus 1 . The control unit 100 includes the document feeding unit 6, the document reading unit 5, the image recording unit 12, the paper feeding unit 14, the paper conveying unit 19, the cleaning unit 8, the operating unit 47, the driving mechanism 88, the conveying unit 125, and the lifting mechanism 129. , and a washing liquid pump 130 to control the driving of these parts.

The control unit 100 controls a cleaning operation of wiping the ink ejection surface 361 with the wiper member 821 using the cleaning liquid 831, and controls an air bubble removal operation that is executed before the control of this cleaning operation, as will be described later. .

Here, the configuration of the recording unit 3 will be described in detail with reference to the drawings. FIG. 4A is a diagram showing a recording section and a transport unit. FIG. 4B is a top view of the transport unit and the recording section.

The transport unit 125 is arranged below the line heads 31 to 34, as shown in FIG. 4A. The transport unit 125 transports the paper P while facing the ink ejection surface 361 . The gap between the transport belt 128 and the ink ejection surface 361 is adjusted so that the gap between the surface of the paper P and the ink ejection surface 361 during image recording is, for example, 1 mm.

The recording unit 3 includes line heads 31 to 34, as shown in FIG. 4B. The line heads 31 to 34 are long in a width direction D2 (the width direction of the paper P) perpendicular to the paper P transport direction D1. The width of the line heads 31 to 34 has a length corresponding to the width of the maximum width paper P to be conveyed. Each of the line heads 31 to 34 is fixed to a head frame 35 at predetermined intervals along the paper P transport direction D1. Each of the line heads 31 to 34 has a plurality (eg, three) of recording heads 36 . Therefore, the recording section 3 is provided with 12 recording heads 36 .

The recording head 36 has a plurality of ink nozzles 37 having ink ejection openings 371 from which ink is ejected. In FIG. 4B, the plurality of ink nozzles 37 are simply shown as being arranged in one row, but they are arranged in three rows in a zigzag manner as shown in FIG. It is The lower surface of the recording head 36 is an ink ejection surface 361 provided with ink ejection ports 371 . In this embodiment, the line head 31 has three recording heads 36 arranged in a zigzag pattern along the width direction D2. Each of the other line heads 32 to 34 also has three recording heads 36 arranged in a zigzag pattern along the width direction D2 in the same manner as the line head 31 .

The recording unit 3 records an image on the paper P transported by the transport unit 125 by ejecting ink from each ink nozzle 37 of each recording head 36 . As the ink ejection method of the line heads 31 to 34, for example, a piezo method in which ink is ejected using a piezo element, a thermal method in which ink is ejected by generating air bubbles by heating, or the like is adopted.

As shown in FIG. 1, the ink tank 122 includes ink tanks 41, 42, 43, and 44 containing inks corresponding to black, cyan, magenta, and yellow. The ink tanks 41 to 44 are connected to the line heads 31 to 34 of the same color by ink tubes (not shown). The line heads 31-34 are supplied with ink from ink tanks 41-44, respectively. Here, as the ink, for example, a solvent and water containing a coloring material corresponding to each color is used.

As shown in FIG. 2, when the transport unit 125 is at the maintenance position, the cleaning unit 8 performs an air bubble removal operation, which will be described later, and a subsequent cleaning operation (including a purge operation) to clean the line heads 31 to 31. 34 is a device for restoring the function of each recording head 36 . The cleaning section 8 has an ink tray 81 and a wiper unit 82 as shown in FIGS. 1 and 5A. FIG. 5A is a partially broken side view showing a state in which the ink tray and wiper unit of the cleaning section are arranged below the recording section. FIG. 5B is a view of the ink ejection surface of the print head.

The ink tray 81 receives ink ejected from the ink nozzles 37 of each recording head 36 . The ink tray 81 is movably supported in the horizontal direction (horizontal direction in FIG. 1) by a first moving mechanism (not shown). The first moving mechanism is, for example, a driving mechanism 88 that horizontally moves the ink tray 81 using a rack-and-pinion mechanism that converts the rotational motion of a gear connected to the rotating shaft of a motor into linear motion. . The ink tray 81 is arranged at a retracted position (see the position indicated by the one-dot chain line in FIG. 2) retracted downstream of the recording unit 3 in the transport direction D1 during normal operation (during printing).

Then, when an instruction to perform a cleaning operation is input, the ink tray 81 is moved to the maintenance position by the lifting mechanism 129, and the ink tray 81 fills the space created between the line heads 31 to 34 by moving the transport unit 125 to the maintenance position. , is moved by said first moving mechanism (see position indicated by solid lines in FIG. 2). Also, the ink tray 81 is supported so as to be able to move up and down in the vertical direction (vertical direction in FIG. 1). When the ink tray 81 is moved to a position facing the line heads 31 to 34, the lift mechanism 129 lifts the transport unit 125 by a predetermined distance from the maintenance position, thereby moving upward.

The wiper unit 82 has a configuration in which a plurality of wiper members 821 for cleaning ink adhering to each ink ejection surface 361 are supported by a pair of side frames 823 via a plurality of stays 822 . Also, the wiper unit 82 is movable along the width direction D2. In particular, the plurality of wiper members 821 are movable in the wiping direction D21 from the cleaning liquid supply portion 83 while contacting the ink ejection surface 361 (see FIG. 9, which will be described later).

The plurality of wiper members 821 clean the ink ejection surface 361 with cleaning liquid 831 (see FIG. 8) supplied from the cleaning liquid supply section 83 by moving along the wiping direction D21.

Here, the plurality of wiper members 821 are made of elastomer, for example, and are formed in a plate shape with a thickness of 1 mm to 2 mm, and have elasticity. Examples of elastomers include urethane rubber, ethylene propylene diene rubber (EPDM), nitrile rubber (NBR), styrene rubber (SBR), chloroprene rubber, silicone rubber, and fluororubber.

A plurality of stays 822 extend along the transport direction D1 and are connected to a pair of side frames 823 . In this embodiment, the number of stays 822 is three. Four wiper members 821 are fixed to each stay 822 . That is, the number of wiper members 821 is 12 corresponding to the number of recording heads 36 .

The pair of side frames 823 can be reciprocated along the width direction D2 by a second moving mechanism (not shown). The second movement mechanism is a drive mechanism 88 such as the rack and pinion mechanism. For example, by applying a rotational force to the side frame 823 functioning as a rack via a pinion gear (not shown), the side frame 823 reciprocates along the width direction D2. As a result, the entire wiper unit 82 including the plurality of wiper members 821 reciprocates along the width direction D2.

As shown in FIGS. 5A and 5B, the recording head 36 is provided with a cleaning liquid supply section 83 upstream of the ink ejection surface 361 in the wiping direction D21. The cleaning liquid supply unit 83 includes a cleaning liquid supply surface 865 having a cleaning liquid supply port 834 for supplying a cleaning liquid 831 used for wiping the ink ejection surface by the wiper member 821, and is provided upstream of the ink ejection surface 361 in the wiping direction D21. ing.

The cleaning liquid supply part 83 has an inclined surface 866 which is positioned upstream in the wiping direction D21 continuously from the cleaning liquid supply surface 865 and which is inclined upward with respect to the cleaning liquid supply surface 865 as it advances upstream in the wiping direction D21. ing.

As shown in FIG. 4B, the recording unit 3 has a plurality (12) of cleaning liquid supply units 83 because it has twelve recording heads 36 . A plurality (twelve) of cleaning liquid supply units 83 supply cleaning liquid 831 for cleaning the ink ejection surface 361 . The cleaning liquid supply unit 83 supplies the cleaning liquid 831 contained in the accommodation space 832 through the cleaning liquid nozzle 833 communicating with the accommodation space 832 when the wiper member 821 cleans the ink ejection surface 361 .

As shown in FIG. 8A, which will be described later, the cleaning liquid 831 is supplied in a state of protruding hemispherically from a cleaning liquid supply port 834 provided in the cleaning liquid nozzle 833 when cleaning the ink ejection surface 361 . On the other hand, the cleaning liquid 831 forms a concave meniscus inside the cleaning liquid nozzle 833 except when cleaning the ink ejection surface 361 . Here, the concave meniscus can be formed by adjusting the inner diameter of the cleaning liquid nozzle 833, the negative pressure that the accommodation space 832 applies to the inside of the cleaning liquid nozzle 833, and the like.

5A and 5B, the recording head 36 is provided with a scattering prevention member 84 downstream of the ink ejection surface 361 in the wiping direction D21. The scattering prevention member 84 has an inclined surface 841 with which the wiper member 821 comes into contact after the wiper member 821 wipes the ink discharge surface 361 . The inclined surface 841 is positioned downstream in the wiping direction D21 continuously from the ink ejection surface 361, and is inclined upward with respect to the ink ejection surface 361 as it progresses downstream in the wiping direction D21. Therefore, as the wiper member 821 advances in the wiping direction D21 while contacting the inclined surface 841 of the scatter prevention member 84, the deflection of the wiper member 821 gradually decreases. It gently separates from the inclined surface 841 . Therefore, splashing of the liquid can be reduced as compared with a configuration that does not have the splash prevention member 84 . Also, the anti-scattering member 84 is made of, for example, polyacetal resin (POM). The ink ejection surface 361 of the recording head 36 is treated with a fluorine-based water-repellent film, for example. Therefore, the water repellency of the anti-scattering member 84 is lower than that of the ink ejection surface 361 . Therefore, even if the cleaning liquid remains on the anti-splashing member 84, the height of the droplets is low, so it is possible to reduce the contact of the droplets with the paper.

The cleaning liquid storage section 85 stores a cleaning liquid 831 as shown in FIG. 5(A). Here, as the cleaning liquid 831, for example, ink obtained by removing the coloring material can be used. That is, as the cleaning liquid 831, a liquid containing solvent and water as main components can be used. Further, a surfactant, an antiseptic antifungal agent, and the like are added to the cleaning liquid 831 as necessary.

FIG. 6 is a diagram schematically showing cleaning liquid flow paths for supplying cleaning liquid to one line head. FIG. 6 shows the cleaning liquid flow path 87 for the line head 31 . The cleaning liquid flow path 87 is a pipe for guiding the cleaning liquid 831 from the cleaning liquid storage section 85 to the cleaning liquid supply sections 83 of the plurality (for example, three) of the recording heads 36 . The cleaning liquid flow path 87 is provided for each of the line heads 31-34. That is, one cleaning liquid channel 87 is provided for each color. The cleaning liquid flow paths 87 of the other line heads 32 to 34 are the same as those of the line head 31. FIG.

The cleaning liquid flow path 87 includes a vertical tubular member 871 and a horizontal tubular member 872 . The vertical tubular member 871 is a vertical pipe whose one end is connected to the cleaning liquid supply section 83 and whose length from one end to the other end extends above the cleaning liquid supply section 83, and which is shaded in FIG. The horizontal tubular member 872 is a horizontal pipe having one end connected to the upper end side of the vertical tubular member 871 and extending horizontally from the one end to the other end. The capacity of the horizontal tubular member 872 is, for example, five times the total capacity of the cleaning liquid supply section 83 and the vertical tubular member 871 .

The horizontal tubular member 872 also includes a check valve 873 that guides the cleaning liquid 831 in the direction of the vertical tubular member 871 . As a result, the cleaning liquid 831 can be prevented from returning to the cleaning liquid storage section 85, and the pushing control of the cleaning liquid 831 can be stably performed.

The cleaning liquid pump 130 provides power to move the cleaning liquid 831 in the cleaning liquid flow path 87 and push out the cleaning liquid 831 from the cleaning liquid supply port 834 . The output side of the cleaning liquid pump 130 is connected to the cleaning liquid flow path 87 , and the input side of the cleaning liquid pump 130 is connected to the input side flow path connected to the cleaning liquid storage section 85 . There is one cleaning fluid pump 130 for each cleaning fluid channel 87, ie, one for each color. In addition, the cleaning liquid pump 130 is an example of a driving unit in the scope of claims.

Further, as shown in FIG. 6, the channel lengths L1, L2, and L3 from the cleaning liquid pump 130 to the cleaning liquid supply portions 83 of the three recording heads 36 of the same color are the same. As a result, in the cleaning liquid flow path 87 composed of the vertical tubular member 871 and the horizontal tubular member 872, the pushing amount of each cleaning liquid supply section 83 can be the same.

Next, an example of processing performed by the control unit 10 of the inkjet recording apparatus 1 according to the first embodiment will be described with reference to the drawings. FIG. 7A is a flowchart showing an example of processing performed by the inkjet printing apparatus according to the first embodiment.

As shown in FIG. 7A, the control unit 100 determines whether or not maintenance is started (S1). Specifically, for example, the control unit 100 determines that maintenance is to be started when a predetermined time before printing is started after the power supply of the inkjet recording apparatus 1 is turned on (YES in S1), as shown in FIG. , the transport unit 125 is moved to the maintenance position, and the cleaning section 8 is moved to the position directly below the recording section 3. As shown in FIG. In addition, the maintenance start timing is not limited to the above case. Various timings such as when the number of printed sheets exceeds a predetermined cumulative number of sheets.

When the control unit 100 determines that maintenance is to be started (YES in S1), the control unit 100 determines whether or not a predetermined execution condition (that is, a condition for determining whether or not to control the bubble removal operation of the entire system) is established. Determine (S2). The control unit 100 controls the entire system bubble removing operation only when a predetermined execution condition is satisfied before controlling the cleaning operation. The predetermined execution condition is, for example, that the number of executions of cleaning operation control reaches a predetermined number of times (for example, 15 times). Specifically, when the number of cleaning execution times has not reached a predetermined number (for example, 15 times) (NO in S2), the control unit 100 performs a bubble removing operation different from the system-wide bubble removing operation. control (hereinafter sometimes referred to as "vertical pipe bubble removal control") is performed (S3).

Here, the control of the air bubble removal operation (vertical tube air bubble removal control) in S3 will be described. FIGS. 8A to 8E are partially cutaway side views for explaining the air bubble removal operation performed before the cleaning operation.

With the cleaning unit 8 moved to a position directly below the recording unit 3 (see FIG. 8A), the control unit 100 drives the lifting mechanism 129 to raise the conveying unit 125 by a predetermined distance from the maintenance position. , the ink tray 81 is placed at the purge position directly below the ink ejection surface 361 (see FIG. 8B). As a result, the plurality of wiper members 821 of the cleaning section 8 are positioned directly below the inclined surface 866 of the cleaning liquid supply section 83 adjacent to the corresponding recording head 36 (see FIG. 8B). At this time, the tips of the plurality of wiper members 821 are positioned above the plane including the cleaning liquid supply surface 865 . The position where the tip of the wiper member 821 is arranged in the area directly below the inclined surface 866 and above the plane including the cleaning liquid supply surface 865 is the movement start position of the wiper member 821 in the bubble removing operation.

The control unit 100 performs control of the air bubble removal operation (vertical tube air bubble removal control) including the following (i) to (iii) (S3).

The controller 100 (i) pushes out the cleaning liquid 831 in an amount of 0.5 to 0.9 times the total capacity of the cleaning liquid supply section 83 and the vertical tubular member 871 through the cleaning liquid supply port 834 (FIG. 8B). reference). Experimental data shown in FIG. 10, which will be described later, confirms that the amount of cleaning liquid 831 that is 0.5 times or more and 0.9 times or less of the total volume is suitable. The cleaning liquid 831 discharged to the ink tray 81 is discharged from a discharge port provided at the bottom of the ink tray 81 through an ink tube (not shown) to a predetermined waste ink reservoir.

Subsequently, the control unit 100 drives the second moving mechanism (not shown) to horizontally move the wiper unit 82 along the wiping direction D21, thereby (ii) moving the wiper member 821 to the cleaning liquid supply surface 865. It is moved in the wiping direction D21 from the movement start position, which is a position on the upstream side in the wiping direction D21, to a position in front of the ink ejection surface (see FIGS. 8(C) and 8(D)).

Subsequently, the controller 100 drives the lifting mechanism 129 to lower the conveying unit 125 by a predetermined distance and return it to the maintenance position, thereby (iii) moving the wiper member 821 to the cleaning liquid state as shown in FIG. 8E. Control to separate from the supply surface 865 is performed.

On the other hand, when the number of times cleaning has been performed reaches a predetermined number (for example, 15 times) (YES in S2), the control unit 100 controls the entire system bubble removal operation instead of the vertical pipe bubble removal control. (S4). It should be noted that the non-volatile memory incorporated in the control unit 10 stores the number of cleaning execution times each time cleaning is executed.

When the number of cleaning execution times has reached a predetermined number (for example, 15 times) (YES in S2), the control section 100 controls the entire system bubble removal operation (S4). FIG. 7B is a flow chart showing an example of the system-wide bubble removal process.

The control unit 100 determines whether or not the setting for pushing out the cleaning liquid 831 at the time of air bubble removal from the entire system is the setting for pushing out multiple times (S41). Specifically, the setting for pushing out the cleaning liquid 831 is stored in advance in the non-volatile memory incorporated in the control unit 10 . If the push-out setting of the cleaning liquid 831 stored in advance in the non-volatile memory is one time, the control unit 100 determines that the push-out is performed once. Determined to push out.

When the control unit 100 determines that the push-out setting of the cleaning liquid 831 at the time of all-system air bubble removal is set to push out multiple times (YES in S41), it controls the whole-system air bubble removal operation by pushing out multiple times (S42). .

The control unit 100 controls the entire system bubble removal operation including the following (iA), (ii) and (iii) (S42). The control of the air bubble removal operation of the entire system differs from the above-described vertical pipe air bubble removal control in that the amount of cleaning liquid 831 pushed out is increased. As shown in (E), it is the same as the case of the above-described vertical pipe bubble vent control.

(iA) When the cleaning liquid 831 is pushed out from the cleaning liquid supply port 834 a plurality of times, the controller 100 supplies the cleaning liquid 831 in an amount of 0.5 to 1 time the capacity of the horizontal tubular member 872 for the plurality of times. It is extruded from the cleaning liquid supply port 834 multiple times so that the total amount of extrusion is 1.5 times or more the capacity of the horizontal tubular member 872 (see FIG. 8(B)). It was confirmed by experimental data shown in FIG.

Subsequently, the control unit 100 (ii) moves the wiper member 821 in the wiping direction D21 from the movement start position, which is a position upstream of the cleaning liquid supply surface 865 in the wiping direction D21, to a position in front of the ink ejection surface. (Refer to FIG. 8(C) and FIG. 8(D)). Subsequently, the controller 100 (iii) performs control to separate the wiper member 821 from the cleaning liquid supply surface 865 as shown in FIG. 8(E). Note that (ii) and (iii) above are the same as (ii) and (iii) in the case of the above-described vertical tube air bubble venting control, so detailed description thereof will be omitted here.

On the other hand, in S41, when the control unit 100 determines that the push-out setting of the cleaning liquid 831 at the time of all-system air bubble removal is the one-time push setting (NO in S41), the control unit 100 controls the whole-system air bubble removal operation by one-time push. (S43). It was confirmed by experimental data shown in FIG.

The control unit 100 controls the entire system bubble removal operation including the following (iB), (ii) and (iii) (S43). (iB) When pushing out the cleaning liquid 831 from the cleaning liquid supply port 834 at one time, the controller 100 pushes the cleaning liquid 831 in an amount equal to or more than 1.5 times the capacity of the horizontal tubular member 872 from the cleaning liquid supply port 834 at one time. Extrude, and perform the above (ii) and (iii) (S43).

As shown in FIG. 7(A), the control unit 100 performs the vertical pipe bubble removal control process (S3) or the overall system bubble removal control process (S4), and then controls the cleaning operation (S5). ). 9A to 9E are partially broken side views for explaining the cleaning operation.

As shown in FIG. 9A, the control unit 100 supplies the purge ink 45 to the recording head 36 and causes the purge ink 45 to be discharged from the ink ejection openings 371 of the ink nozzles 37 . As a result, thickened ink, foreign matter, air bubbles, etc. in the ink nozzles 37 are discharged toward the ink tray 81 together with the purge ink 45 supplied to the ink nozzles 37 . By performing such a purge operation, clogging of the ink nozzles 37 is eliminated. The ink discharged to the ink tray 81 is discharged from a discharge port provided at the bottom of the ink tray 81 through an ink tube (not shown) to a predetermined waste ink reservoir.

When the purge operation ends, the cleaning section 8 performs a cleaning operation. The cleaning operation is an operation for wiping off the purge ink 45 adhering to the ink ejection surface 361 with the wiper member 821 . In the cleaning operation, the controller 100 pushes out a predetermined amount (for example, 1.5 mL) of the cleaning liquid 831, and the cleaning liquid 831 protrudes in a hemispherical shape from the cleaning liquid supply port 834 of the cleaning liquid supply section 83 and is supplied (FIG. 9(A)). The predetermined amount (for example, 1.5 mL) is the total amount of extrusion of each of the line heads 31 to 34, that is, the amount of extrusion for the total of the four colors. Also, the cleaning liquid 831 may be supplied at the same time as the purge ink 45 is discharged, or before or after the purge ink 45 is discharged.

As shown in FIGS. 9B to 9D, when the supply of the cleaning liquid 831 is completed, the controller 100 drives the second moving mechanism (not shown) to move the wiper unit 82 in the wiping direction D21. move horizontally along the Specifically, the control unit 100 positions the wiper member 821 at the movement start position (see FIG. 9B), and moves the wiper member 821 from the movement start position to the end position where the scatter prevention member 84 is contacted. The member 821 is moved (see FIGS. 9(C) and 9(D)). At this time, the wiper member 821 moves through the inclined surface 866 , the cleaning liquid supply port 834 , and the ink ejection surface 361 while contacting the scattering prevention member 84 .

Further, as shown in FIG. 9D, the plurality of wiper members 821 wipe off the purge ink 45 adhering to the ink ejection surface 361 when moving in contact with the ink ejection surface 361 . Residual ink wiped off by the plurality of wiper members 821 moves downward along the surfaces of the wiper members 821 together with the cleaning liquid 831 and drops onto the ink tray 81 .

Subsequently, the control unit 100 drives the lifting mechanism 129 to lower the transport unit 125 by a predetermined distance and return it to the maintenance position, thereby moving the wiper member 821 to the scattering prevention member 84 as shown in FIG. 9E. keep away from

After that, the control section 100 drives the lifting mechanism 129 to lower the transport unit 125 to the maintenance position (see FIG. 2), and drives the first moving mechanism to move the ink tray 81 of the cleaning section 8 to the retracted position. (see Figure 1). The control section 100 also drives the lifting mechanism 129 to return the transport unit 125 to the recording position (the position shown in FIG. 1). Then, the control unit 100 terminates the processing shown in FIG. 7(A).

Here, the experimental data of the vertical tube air bubble venting will be described with reference to FIG. 10 . FIG. 10 is a diagram showing the results of experimental data for vertical pipe bubble venting. As shown in FIG. 6, the line head 31 has three pairs of cleaning liquid supply units 83 and vertical tubular members 871 . That is, for one color, there are three sets of cleaning liquid supply units 83 and vertical tubular members 871 . Therefore, for four colors, there are 12 sets (=3 sets×4 colors) of the cleaning liquid supply part 83 and the vertical tubular member 871 . The total capacity of the 12 pairs of cleaning liquid supply units 83 and vertical tubular members 871 is, for example, 4 mL.

Air was previously introduced into the vicinity of the vertical tubular member 871 and the cleaning liquid supply port 834, and then the cleaning liquid supply port 834 was operated to remove air bubbles, that is, the amount of the cleaning liquid 831 extruded was 4.0 mL, 3.6 mL, and 2.8 mL, respectively. , 2.0 mL, and 1.2 mL, and then the cleaning operation. The number of experiments N for each amount of extrusion was performed 10 times. According to the experimental data shown in FIG. 10, the cleaning liquid 831 is preferably used in an amount of 0.5 to 0.9 times the total volume (magnification A in FIG. 10 is 0.5 to 0.9). confirmed.

Next, experimental data for air bubble removal from the entire system will be described with reference to FIG. 11 . FIG. 11 is a diagram showing the results of experimental data for air bubble removal from the entire system. The line head 31 has three horizontal tubular members 872 as shown in FIG. That is, there are three horizontal tubular members 872 for one color. Therefore, for four colors, there are 12 horizontal tubular members 872 (=3 pieces×4 colors). The total capacity of the twelve horizontal tubular members 872 is, for example, 20 mL.

After introducing air into the horizontal tubular member 872 in advance, the horizontal tubular member 872 is operated to remove air bubbles. An experiment was conducted in which the cleaning operation was performed after performing the entire system air-bleeding operation of extruding 1 to 3 times, extruding 10 mL 1 to 3 times, and extruding 6.0 mL 1 to 6 times. The number of experiments N for each amount of extrusion was performed 10 times.

From the experimental data shown in FIG. 11, it was confirmed that it is preferable to push out the washing liquid 831 once at 30 mL. That is, the amount (=30 mL) of the cleaning liquid 831 that is 1.5 times (the magnification B in FIG. 11 is 1.5) or more of the capacity (=20 mL) of the horizontal tubular member 872 can be pushed out from the cleaning liquid supply port 834 at one time. preferred.

Further, according to the experimental data shown in FIG. 11, in the case of multiple extrusions, the extrusion amount of the cleaning liquid 831 is 20 mL and the extrusion amount is 20 mL, the extrusion amount of the cleaning liquid 831 is 14 mL and the extrusion amount is 3 times, and the extrusion amount of the cleaning liquid 831 is Three extrusions with 10 mL was found to be suitable. That is, the amount (=10 mL to 20 mL) of the cleaning liquid 831 is 0.5 to 1 times the capacity (=20 mL) of the horizontal tubular member 872 (magnification B in FIG. 11 is 0.5 to 1.0). is preferably extruded from the cleaning liquid supply port 834 multiple times so that the total amount of the multiple extrusions is 1.5 times or more the capacity (=20 mL) of the horizontal tubular member 872 .

According to the first embodiment, the cleaning liquid flow path 87 includes a vertical tubular member 871 having one end connected to the cleaning liquid supply section 83 and extending above the cleaning liquid supply section 83 from one end to the other end; is connected to the upper end side of the vertical tubular member 871 and has a horizontal tubular member 872 extending horizontally from one end to the other end. As long as the cleaning liquid 831 is not pushed out, air bubbles existing in the vertical tubular member 871 can be stopped in the vertical tubular member 871, air bubbles existing in the horizontal tubular member 872 can be stopped in the horizontal tubular member 872, and the vertical tubular member 872 can stop air bubbles. Air bubbles can be separated by the member 871 and the horizontal tubular member 872 . Further, the vertical tubular member 871 forms a flow path in the vertical direction. Air bubbles may be absent or less likely to occur in the portion of the flow path between the sides. As a result, it is possible to provide a cleaning liquid flow path capable of suitably realizing bubble removal control while suppressing the supply amount of the cleaning liquid 831 . In addition, the control unit 100 pushes out at least part of the cleaning liquid 831 in the cleaning liquid flow path 87 from the cleaning liquid supply port 834 before controlling the cleaning operation of wiping the ink ejection surface 361 of the recording head 36 . It controls the bubble removing operation of the flow path 87 . That is, since the bubble removal operation is controlled before the cleaning operation is controlled, image defects due to paper stains can be reduced compared to a configuration that simply controls the cleaning operation.

10, the controller 100 controls the air bubble removal operation (vertical tube air bubble removal control) by: By pushing out 0.9 times or less of the cleaning liquid 831 from the cleaning liquid supply port 834, the air bubbles existing in the cleaning liquid supply part 83 and the air bubbles existing on the lower end side of the vertical tubular member 871 can be pushed out together with the cleaning liquid 831. The cleaning liquid 831 at the supply port 834 can be free of bubbles. By the way, if the amount of the cleaning liquid 831 that is one times the total capacity is pushed out from the cleaning liquid supply port 834, the air bubbles existing on the upper end side of the vertical tubular member 871 will reach the cleaning liquid supply port 834, and the air bubbles will flow into the cleaning liquid. It becomes foam at the supply port 834 . On the other hand, since the amount of the cleaning liquid 831 is limited to 0.9 times or less of the total capacity, it is possible to prevent the air bubbles existing on the upper end side of the vertical tubular member 871 from reaching the cleaning liquid supply port 834. Thus, it is possible to prevent the generation of bubbles caused by air bubbles existing on the upper end side of the vertical tubular member 871, and the cleaning liquid 831 in the cleaning liquid supply port 834 can be in a bubble-free state. Since (ii) the wiper member 821 is moved in the wiping direction D21 and (iii) the wiper member 821 is separated from the cleaning liquid supply surface 865, bubbles do not remain on the cleaning liquid supply surface 865. Therefore, it is possible to suitably control the bubble removing operation. After the bubble removing operation, the cleaning operation is controlled. That is, since the cleaning operation of wiping the ink ejection surface 361 with the wiper member 821 using the cleaning liquid 831 without bubbles is controlled, no bubbles remain on the ink ejection surface 361 of the print head 36 . As a result, it is possible to reduce the occurrence of image defects due to paper stains.

Further, as control of the cleaning operation, the control unit 100 pushes out the purge ink 45 from the ink ejection port 371 of the recording head 36, pushes out the cleaning liquid 831 from the cleaning liquid supply port 834, and causes the wiper member 821 to eject ink from the movement start position. Control is performed such that the wiper member 821 is moved in the wiping direction D21 to the end position, which is the position where it contacts the scattering prevention member 84 via the surface 361, and is separated from the end position. For this reason, the wiper member 821 is separated from the scatter prevention member 84, so that the ink ejection surface 361 is not left with liquid residue. In addition, the splash prevention member 84 can prevent the liquid (ink or cleaning liquid) from splashing when the wiper member 821 moves away.

Further, the inclined surface of the cleaning liquid supply part 83 is positioned on the upstream side in the wiping direction D21 continuously from the cleaning liquid supply surface 865, and is inclined upward with respect to the cleaning liquid supply surface 865 as it progresses toward the upstream side in the wiping direction D21. ing. The movement start position is a predetermined position where the tip of the wiper member 821 is positioned directly below the inclined surface and above the plane including the cleaning liquid supply surface 865 . Thereby, the wiper member 821 can be preferably brought into contact with the cleaning liquid supply surface 865 and the ink ejection surface 361 .

In addition, as the control of the air bubble removal operation of the entire system, the control unit 100 (iA) pushes out the cleaning liquid 831 from the cleaning liquid supply port 834 a plurality of times. The following amount of cleaning liquid 831 is extruded from the cleaning liquid supply port 834 multiple times so that the total amount of the multiple extrusions is 1.5 times or more the capacity of the horizontal tubular member 872, thereby extruding the cleaning liquid 831 existing in the cleaning liquid supply section 83. Air bubbles existing in the vertical tubular member 871 and air bubbles existing in the horizontal tubular member 872 can all be pushed out together with the cleaning liquid 831, and the cleaning liquid 831 at the cleaning liquid supply port 834 can be free of bubbles. In addition, the control unit 100 controls the overall system bubble removal operation (iB) when the cleaning liquid 831 is pushed out from the cleaning liquid supply port 834 at one time, the volume of the horizontal tubular member 872 is 1.5 times or more. By pushing out the cleaning liquid 831 from the cleaning liquid supply port 834 at one time, all the air bubbles existing in the cleaning liquid supply part 83, the air bubbles existing in the vertical tubular member 871, and the air bubbles existing in the horizontal tubular member 872 can be pushed out together with the cleaning liquid 831. , and the cleaning liquid 831 in the cleaning liquid supply port 834 can be in a bubble-free state. Further, the control of the system-wide bubble removal operation is not executed every time before the control of the cleaning operation, but is executed only when a predetermined execution condition is satisfied before the control of the cleaning operation. Therefore, the consumption of the cleaning liquid 831 can be suppressed. Since (ii) the wiper member 821 is moved in the wiping direction D21 and (iii) the wiper member 821 is separated from the cleaning liquid supply surface 865, no bubbles remain on the cleaning liquid supply surface 865. Therefore, it is possible to suitably control the bubble removing operation. After the bubble removing operation, the cleaning operation is controlled. That is, since the cleaning operation of wiping the ink ejection surface 361 with the wiper member 821 using the cleaning liquid 831 without bubbles is controlled, no bubbles remain on the ink ejection surface 361 of the print head 36 . As a result, it is possible to reduce the occurrence of image defects due to paper stains.

Further, the control of the air bubble removal operation of the entire system is executed when the number of execution times of the control of the cleaning operation reaches a predetermined number of times. That is, the control of the air bubble removal operation of the entire system is executed once out of a plurality of times. Thereby, the consumption of the cleaning liquid 831 can be suppressed.

Next, an inkjet recording apparatus 1 according to a second embodiment will be described. FIG. 12 is a functional block diagram schematically showing the main internal configuration of an inkjet printing apparatus according to the second embodiment.

In the first embodiment described above, when the number of cleaning operation control executions reaches a predetermined number (for example, 15 times), the entire system air bubble removal operation is controlled. is lower than the allowable print temperature when the power of the inkjet recording apparatus 1 is turned on, and then the ambient temperature of the recording head 36 reaches the allowable print temperature one or more times. It differs from the above-described first embodiment in that control is performed.

As shown in FIG. 12, the image recording unit 12 of the second embodiment includes heaters capable of heating ink on the ink supply path leading to the recording head 36 for each of the line heads 31 to 34 shown in FIG. 4(B). H1, an ink temperature sensor TS1 that detects the temperature of the ink heated by the heater H1, and an ambient temperature sensor TS2 that detects the ambient temperature of the recording head 36.

The control unit 100 determines whether or not the ink temperature detected by the ink temperature sensor TS1 is at the print permission temperature, and permits printing by the recording unit 3 when it is determined that the ink temperature is at the print permission temperature. Then, it is determined whether or not the ambient temperature of the recording head 36 detected by the ambient temperature sensor TS2 is the print permission temperature.

Then, the control unit 100 sets, as the predetermined execution condition, that the ambient temperature of the recording head 36 is lower than the print permission temperature when the ink jet recording apparatus 1 is turned on, and then the ambient temperature of the recording head 36 is lower than the print permission temperature. When the temperature is reached once or more than once, control of the entire system bubble removal operation is performed.

By the way, in an ink jet printing apparatus in which the printhead is equipped with a heater, the ambient temperature of the printhead (in other words, the temperature inside the apparatus) changes from low to high, and even at low temperatures it is higher than the outside air temperature. As a characteristic of the liquid, the dissolved air content is higher at low temperature and lower at high temperature. At this time, if microbubbles or the like are present in the cleaning liquid, the microbubbles grow larger starting from these microbubbles. When the liquid temperature in the cleaning liquid channel drops again, the air permeating the cleaning liquid channel dissolves into the cleaning liquid. Repeated temperature fluctuations fill the cleaning liquid channel with air bubbles, and in the worst case, they are pushed out. Even if the operation is performed, a predetermined amount of the cleaning liquid does not come out from the cleaning liquid supply port 834 . In addition, when the cleaning is defective, the ink ejection port 371 is clogged (for example, nozzle clogging), white streaks due to unstable flight, and the drying of the ink in the capped state is faster than predetermined, resulting in image defects such as intermittent ejection failure.

Therefore, the control of the bubble removal operation of the entire system is such that the ambient temperature of the recording head 36 is lower than the print permission temperature when the ink jet recording apparatus 1 is turned on, and then the ambient temperature of the recording head 36 reaches the print permission temperature. is executed one or more times. For example, when air bubbles are generated in the cleaning liquid flow path 87 due to temperature fluctuations, they cannot be pushed out by simply controlling the air bubble removal operation as described above. Therefore, when there is a high probability that bubbles are generated in the cleaning liquid channel 87, it is possible to control the entire system air bubble removal operation, and to remove all the bubbles generated in the cleaning liquid channel 87 due to temperature fluctuations. can be pushed out. As a result, cleaning failures can be reduced, and the occurrence of image defects such as intermittent ejection failures can be prevented.

Moreover, the present invention is not limited to the configuration of the above embodiment, and various modifications are possible. Further, in the above-described embodiment, a multi-function machine is used as an embodiment of the inkjet recording apparatus according to the present invention, but this is only an example, and for example, other inkjet recording apparatuses having a printer function can also be used. good.

Further, in the above embodiment, the configuration and processing shown in FIGS. 1 to 12 are merely one embodiment of the present invention, and are not intended to limit the present invention to the configuration and processing.

1 Inkjet recording device 8 Cleaning unit 12 Image recording unit 36 Recording head 83 Cleaning liquid supply unit 84 Splash prevention member 85 Cleaning liquid storage unit 87 Cleaning liquid flow path 100 Control unit 130 Cleaning liquid pump (driving unit)
371 Ink discharge port 821 Wiper member 866 Inclined surface 871 Vertical tubular member 872 Horizontal tubular member 873 Check valve H1 Heater TS1 Ink temperature sensor TS2 Ambient temperature sensor

Claims (5)

a recording head comprising an ink ejection surface having ink ejection openings through which ink is ejected;
a wiper member that wipes the ink ejection surface by contacting the ink ejection surface and moving in a predetermined wiping direction;
a cleaning liquid supply unit including a cleaning liquid supply surface having a cleaning liquid supply port for supplying cleaning liquid used for wiping the ink ejection surface by the wiper member, and provided upstream of the ink ejection surface in the wiping direction;
a cleaning liquid storage unit that stores the cleaning liquid;
a cleaning liquid channel for guiding the cleaning liquid from the cleaning liquid storage section to the cleaning liquid supply section;
a drive unit that provides power to move the cleaning liquid in the cleaning liquid flow path and push the cleaning liquid out of the cleaning liquid supply port;
a control unit that controls a cleaning operation of wiping the ink ejection surface with the wiper member using the cleaning liquid;
The cleaning liquid channel includes a vertical tubular member having one end connected to the cleaning liquid supply section and extending from one end to the other end above the cleaning liquid supply section, and one end connected to the upper end side of the vertical tubular member. and a horizontal tubular member extending horizontally from one end to the other end,
The control unit controls an operation of removing bubbles from the cleaning liquid flow path by pushing out at least a part of the cleaning liquid from the cleaning liquid supply port before controlling the cleaning operation. Device. A plurality of the recording heads are provided for each color,
The drive unit is provided at an upstream end of the cleaning liquid flow path,
The cleaning liquid flow path is a flow path composed of the vertical tubular member and the horizontal tubular member provided for each of the plurality of recording heads,
2. An ink jet recording apparatus according to claim 1, wherein each of said plurality of recording heads has the same flow path length from said drive section to said cleaning liquid supply section. The controller controls the air bubble removal operation by: (i) supplying a cleaning liquid in an amount of 0.5 to 0.9 times the total capacity of the cleaning liquid supply section and the vertical tubular member from the cleaning liquid supply port; (ii) moving the wiper member in the wiping direction from a position upstream of the cleaning liquid supply surface in the wiping direction to a position in front of the ink ejection surface; 3. The inkjet recording apparatus according to claim 2, wherein control is performed to separate the member from the cleaning liquid supply surface. 4. The inkjet recording apparatus according to claim 1, wherein said horizontal tubular member further comprises a check valve for guiding the cleaning liquid toward said vertical tubular member. a splatter prevention member provided downstream in the wiping direction of the ink ejection surface and contacted by the wiper member after the ink ejection surface is wiped by the wiper member;
As control of the cleaning operation, the control section pushes out purge ink from the ink ejection port of the recording head, pushes out cleaning liquid from the cleaning liquid supply port, and moves the wiper member from the movement start position to the ink ejection surface. 5. The wiper member according to any one of claims 1 to 4, wherein the wiper member is moved in the wiping direction to an end position, which is a position where it contacts the scatter prevention member, and the wiper member is separated from the end position. Inkjet recording device.

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