JP6241173B2 - Liquid ejection device - Google Patents

Description

  The present invention relates to a liquid ejection device that ejects liquid.

  Patent Document 1 discloses a liquid ejection device that humidifies a space (ejection space) opposed to an ejection port from an external space (after capping) when the head is not used (when the head is at rest). Have been described. In this humidification maintenance, air in the discharge space is discharged from an air discharge port disposed at one end in the longitudinal direction of the head, and humidified air is discharged from the air supply port disposed at the other end in the longitudinal direction of the head into the space. This is done by supplying to

JP 2011-207091 A

  By the way, when the head is not capped, the discharge port is exposed to the external space. For this reason, the liquid at the discharge port is dried. When the head is used (when recording an image on a recording medium), the liquid at the discharge port is dried for the discharge port where ink is not discharged. As the recording medium conveyance speed at this time increases, the airflow generated in the ejection space by the conveyance of the recording medium increases. Then, drying of the liquid at the discharge port is promoted. For the purpose of suppressing drying of these discharge ports, a technique for performing flushing for discharging ink from the discharge ports is known. However, such flushing causes a problem that the consumption of liquid increases.

  Accordingly, an object of the present invention is to provide a liquid ejection device capable of suppressing the drying of the liquid near the ejection port.

In the liquid discharge apparatus of the present invention, a transport mechanism that transports a recording medium in the transport direction, and a direction perpendicular to the transport direction is a longitudinal direction, and a plurality of ejection ports that eject liquid to the recording medium are along the longitudinal direction. A recording head having discharge surfaces arranged at equal intervals, and extending in the longitudinal direction, arranged upstream of the recording head in the transport direction, and overlaps the plurality of discharge ports along the transport direction A mist head having a discharge surface formed with a discharge port for discharging a transparent liquid mist, a discharge member, a counter member that can face the discharge surface, the counter member, the discharge surface, and the discharge surface. And a partition member that includes the plurality of discharge ports and the discharge port portion together with the opposing member, the discharge surface, and the discharge surface and partitions the space from an external space, and the partition member is the gap A compartment while partitioned from the external space, and a cap mechanism that can take an open state in which the partition member is opened the gap to the external space, on the basis of the recording instruction, when the image recording is performed on the recording medium, the recording as the conveying speed of the medium is increased, the as emissions of the liquid mist per unit time from the outlet portion is increased, and and control means for controlling the mist head, said control means, said when gap of the partition state, to be less than when the emission amount of the liquid mist per unit time image recording is performed on the recording medium, that controls the mist head.

According to this, when an image is recorded on the recording medium, the liquid mist is discharged from the discharge port, and the liquid mist flows into the discharge space facing the discharge surface by the air flow generated by the conveyance of the recording medium. At this time, the faster the recording medium is conveyed, the greater the amount of liquid mist discharged per unit time. For this reason, the humidity of the discharge space is maintained, and the liquid drying near the discharge port can be suppressed. As a result, liquid discharge due to flushing or the like performed to suppress drying can be suppressed. Moreover, it becomes possible to suppress the consumption of the transparent liquid for generating the liquid mist.
In the present invention, color ink is ejected from the plurality of ejection ports, and the control unit is configured to print the image on the recording medium if the image recording is monochrome printing when the image is recorded on the recording medium. If the image recording is color printing, the recording medium is transported at a second predetermined speed slower than the first predetermined speed, and at the time of color printing, the liquid mist per unit time is transported at a predetermined speed. It is preferable to control the transport mechanism and the mist head so that the amount of discharge is less than that during monochrome printing.
Moreover, in this invention, the wiping mechanism which wipes the said discharge surface along the said longitudinal direction is further provided. The mist head has a plurality of divided regions in which the discharge port portion is divided in the longitudinal direction, and the liquid mist is individually discharged from the plurality of divided regions. When the gap is in the partitioned state, the mist is discharged so that the amount of the liquid mist discharged per unit time increases in the divided area on the downstream side with respect to the wiping direction in which the wiping mechanism wipes the discharge surface. It is preferable to control the head. Thereby, when the ejection surface is wiped by the wiping mechanism, the liquid may remain on the downstream side of the ejection surface in the wiping direction. When this residual liquid is dried, the liquid at the discharge port near the residual liquid is easily dried. However, since the discharge amount of the liquid mist per unit time from the divided area on the downstream side in the wiping direction is increased, it is possible to suppress the drying of the residual liquid. For this reason, it becomes possible to suppress the drying acceleration of the liquid at the discharge port due to the drying of the residual liquid.
In another aspect, the liquid ejection apparatus according to the present invention includes a transport mechanism that transports the recording medium in the transport direction, and a plurality of ejection ports that discharge the liquid onto the recording medium with the direction orthogonal to the transport direction as the longitudinal direction. Is a recording head having ejection surfaces arranged at equal intervals along the longitudinal direction, and extends in the longitudinal direction, and is disposed upstream of the recording head with respect to the transport direction and along the transport direction. A mist head having a discharge surface formed with a discharge port portion that overlaps the plurality of discharge ports and discharges a transparent liquid mist, a counter member that can face the discharge surface and the discharge surface, the counter member, and the discharge A partition member that includes the plurality of discharge ports and the discharge port portion together with the opposing member, the discharge surface, and the discharge surface, and divides the gap between the surface and the discharge surface from an external space, Previous A cap mechanism capable of taking a partition state in which the partition member partitions the gap from the external space and an open state in which the partition member opens the gap to the external space, and wiping for wiping the discharge surface along the longitudinal direction. When an image is recorded on a recording medium based on a mechanism and a recording command, the amount of liquid mist discharged from the discharge port unit per unit time increases as the recording medium conveyance speed increases. And a control means for controlling the mist head. The mist head has a plurality of divided regions in which the discharge port portion is divided in the longitudinal direction, and the liquid mist is individually discharged from the plurality of divided regions. When the gap is in the partitioned state, the mist is discharged so that the amount of the liquid mist discharged per unit time increases in the divided area on the downstream side with respect to the wiping direction in which the wiping mechanism wipes the discharge surface. Control the head.
According to this, when an image is recorded on the recording medium, the liquid mist is discharged from the discharge port, and the liquid mist flows into the discharge space facing the discharge surface by the air flow generated by the conveyance of the recording medium. At this time, the faster the recording medium is conveyed, the greater the amount of liquid mist discharged per unit time. For this reason, the humidity of the discharge space is maintained, and the liquid drying near the discharge port can be suppressed. As a result, liquid discharge due to flushing or the like performed to suppress drying can be suppressed. Further, when the ejection surface is wiped by the wiping mechanism, liquid may remain on the downstream side of the ejection surface in the wiping direction. When this residual liquid is dried, the liquid at the discharge port near the residual liquid is easily dried. However, since the discharge amount of the liquid mist per unit time from the divided area on the downstream side in the wiping direction is increased, it is possible to suppress the drying of the residual liquid. For this reason, it becomes possible to suppress the drying acceleration of the liquid at the discharge port due to the drying of the residual liquid.
Further, in the present invention, the control means is configured such that the discharge amount of the liquid mist per unit time from the divided area downstream from the center of the discharge surface with respect to the wiping direction is the discharge surface of the discharge surface with respect to the wiping direction. It is preferable to control the mist head so as to be larger than the discharge amount of the liquid mist per unit time from the divided region upstream from the center.

Further, in the present invention, before Symbol control means along said conveying direction, the higher the divided area where the discharge amount of liquid discharged on the basis of a recording command overlaps less the discharge port, the liquid per unit time It is preferable to control the mist head so that the amount of mist discharged is increased. As a result, it is possible to effectively suppress liquid drying at the discharge port with a small amount of liquid discharge.

  In the present invention, the apparatus further includes a storage unit that stores, for each discharge port, a pause time during which liquid is not continuously discharged from the discharge port. Then, the control means is configured so that a discharge amount of the liquid mist per unit time from the divided region overlapping with the discharge port related to the pause time exceeding a predetermined time along the transport direction is equal to or less than the predetermined time. It is preferable to control the mist head so as to be larger than that in the divided region that overlaps the discharge port related to the downtime along the transport direction. As a result, it is possible to more effectively suppress liquid drying at the discharge port with a small amount of liquid discharge.

  In the present invention, the mist head includes a discharge surface in which a plurality of discharge ports for discharging the liquid mist are arranged along the longitudinal direction, and a plurality of individual channels reaching the discharge ports. Including a unit and a plurality of actuators for applying discharge energy to the transparent liquid in the individual flow path, the divided region is configured by at least one of the discharge ports, and the control means includes the plurality of the plurality of actuators. It is preferable to control the plurality of actuators when discharging the liquid mist from the divided region. Thereby, it becomes possible to change the discharge amount of the liquid mist from each divided region with a simple configuration.

Moreover, in this invention, it is preferable that the length of the said discharge port part is more than the space | interval of the two said outermost discharge ports regarding the said longitudinal direction. As a result, it is possible to suppress liquid drying in the vicinity of all the discharge ports.

Moreover, in this invention, it is preferable that the both ends of the said longitudinal direction of the said discharge outlet part are located in the outer side rather than the said two discharge outlets which are outermost regarding the said longitudinal direction.
Further, in the present invention, the discharge port portion is formed of a plurality of discharge ports arranged along the longitudinal direction and from which the liquid mist is discharged, and the two outermost discharge ports in the longitudinal direction. Is preferably located outside the two outermost outlets.

  In the present invention, a plurality of the recording heads are provided along the transport direction, the plurality of recording heads eject inks of different colors, and the mist head is most upstream in the transport direction. It is preferable that the recording head is disposed upstream of the recording head. Thereby, even if it has a plurality of recording heads, it is possible to suppress liquid drying in the vicinity of the ejection port. For this reason, the liquid discharge by the flushing etc. which are performed in order to suppress drying can be suppressed.

  In the present invention, a plurality of the mist heads are provided, and the plurality of mist heads are arranged adjacent to the plurality of recording heads on the upstream side in the transport direction of the recording head. Is preferred. As a result, it is possible to effectively suppress liquid drying near the ejection opening of each head.

According to the liquid ejection apparatus of the present invention, when an image is recorded on a recording medium, the liquid mist is ejected from the ejection port, and the liquid mist is opposed to the ejection surface by an air flow generated by the conveyance of the recording medium. Flowing into. At this time, the faster the recording medium is conveyed, the greater the amount of liquid mist discharged per unit time. For this reason, the humidity of the discharge space is maintained, and the liquid drying near the discharge port can be suppressed. As a result, liquid discharge due to flushing or the like performed to suppress drying can be suppressed. Moreover, it becomes possible to suppress the consumption of the transparent liquid for generating the liquid mist.
According to another aspect of the liquid ejection apparatus of the present invention, when an image is recorded on a recording medium, the liquid mist is ejected from the ejection port, and the liquid mist is ejected by an air flow generated by the conveyance of the recording medium. It flows in the discharge space facing the surface. At this time, the faster the recording medium is conveyed, the greater the amount of liquid mist discharged per unit time. For this reason, the humidity of the discharge space is maintained, and the liquid drying near the discharge port can be suppressed. As a result, liquid discharge due to flushing or the like performed to suppress drying can be suppressed. Further, when the ejection surface is wiped by the wiping mechanism, liquid may remain on the downstream side of the ejection surface in the wiping direction. When this residual liquid is dried, the liquid at the discharge port near the residual liquid is easily dried. However, since the discharge amount of the liquid mist per unit time from the divided area on the downstream side in the wiping direction is increased, it is possible to suppress the drying of the residual liquid. For this reason, it becomes possible to suppress the drying acceleration of the liquid at the discharge port due to the drying of the residual liquid.

1 is a schematic side view showing an internal structure of an ink jet printer according to an embodiment of a liquid ejection apparatus of the present invention. FIG. 2 is a plan view of a head unit included in the printer of FIG. 1. (A) is a fragmentary sectional view of a head, (b) is an enlarged view which shows the area | region enclosed with the dashed-dotted line of Fig.3 (a). It is sectional drawing regarding the subscanning direction of a cap mechanism and a head unit, (a) shows the condition which a lip member exists in a separation position, (b) shows the condition which a lip member exists in a contact position. FIG. 2 is a block diagram illustrating an electrical configuration of a printer. It is a schematic diagram of a unit waveform output to the driver IC. It is a flowchart which shows the control content of the image recording operation | movement and maintenance operation which a control apparatus of a printer performs. It is an operation | movement condition diagram for demonstrating purge operation | movement and wiping operation | movement. It is a modification of the liquid discharge apparatus of this invention, and is an enlarged side view of the head unit vicinity. It is another modification of the liquid discharge apparatus of this invention, and is a top view of a head unit.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  First, an overall configuration of an ink jet printer 101 as an embodiment of a liquid ejection apparatus according to the present invention will be described with reference to FIG.

  The printer 101 has a rectangular parallelepiped housing 101a. A paper discharge unit 31 is provided on the top plate of the housing 101a. In the internal space of the housing 101a, there are a head unit 1, a platen 5, a paper sensor 32, a paper feed tray 33, a transport mechanism 4, a cap mechanism 40, a head lifting mechanism 70 (see FIG. 5), and a wiper unit 80 (see FIG. 8). ) And the control device 100 and the like are accommodated. The head unit 1 includes four inkjet heads 10 (hereinafter referred to as heads 10) and one mist head 20. These four heads 10 and one mist head 20 each have a substantially rectangular parallelepiped shape that is long in the main scanning direction, and are arranged close to each other in the sub scanning direction. The mist head 20 is disposed upstream of the four heads 10 in the transport direction of the paper P. Here, the main scanning direction is a direction orthogonal to the conveyance direction D of the paper P, and the sub-scanning direction is a direction parallel to the horizontal plane and orthogonal to the main scanning direction.

  Further, in the internal space of the housing 101a, a transport path for transporting the paper P is formed from the paper feed tray 33 toward the paper discharge unit 31 along the thick black arrow shown in FIG. The printer 101 is of a line type that performs recording with these five heads 10 and 20 being fixed.

  In the casing 101a, four cartridges 8 that respectively store yellow, cyan, magenta, and black inks and a cartridge 9 that stores water (transparent liquid) are detachably attached to the casing 101a. ing. Each of the four cartridges 8 is connected to the corresponding head 10 via a tube (not shown) and a pump 10P (see FIG. 5). The cartridge 9 is connected to the mist head 20 via a tube (not shown) and a pump 20P (see FIG. 5). The pump 10P is driven when ink is forcibly sent to the head 10 (that is, at the time of purging or initial ink introduction). The pump 20P is driven when water is initially introduced into the head 20. The pumps 10 </ b> P and 20 </ b> P are in a stopped state other than these, and do not hinder the supply of ink and water to the heads 10 and 20.

  The head unit 1 is supported by the housing 101 a via the head holder 3. Each of the heads 10 and 20 has discharge surfaces 10a and 20a having a plurality of discharge ports 11 and 21 formed on the lower surface thereof. These discharge ports 11 and 21 are arranged at equal intervals along the main scanning direction (see FIG. 2). Ink droplets are ejected from the ejection ports 11 of the ejection surfaces 10a. Water droplets having a size smaller than that of the ink droplets are ejected from the ejection port (discharge port) 21 of the ejection surface (discharge surface) 20a. That is, mist is discharged from the discharge port 21.

  The platen 5 is a flat plate-like member and faces the five heads 10 and 20 in the vertical direction (a direction orthogonal to the main scanning direction and the sub-scanning direction). A predetermined gap suitable for recording is formed between the upper surface 5a of the platen 5 and the ejection surfaces 10a and 20.

  The paper sensor 32 is disposed upstream of the mist head 20 in the transport direction. The paper sensor 32 detects the leading edge of the paper P and outputs a detection signal to the control device 100.

  The paper feed tray 33 is a box having an open top surface and is detachable from the housing 101a. The sheet feed tray 33 can accommodate a plurality of sheets P.

  The transport mechanism 4 includes a paper feed roller 34, five feed roller pairs 35 to 39, and four guides 61 to 64. The paper feed roller 34 is rotated by the drive of a paper feed motor 34 </ b> M (see FIG. 5) under the control of the control device 100, and sends out the uppermost paper P in the paper feed tray 33. The five feed roller pairs 35 to 39 are arranged in this order from the upstream side in the transport direction along the transport path. One roller of each of the feed roller pairs 35 to 39 is a drive roller that is rotated by the drive of feed motors 35M to 39M (see FIG. 5) under the control of the control device 100. The other roller is a driven roller that rotates as the drive roller rotates. The four guides 61 to 64 are alternately arranged with the feed roller pairs 35 to 39 in this order from the upstream side in the transport direction along the transport path. Each guide 61-64 consists of a pair of board arrange | positioned facing each other.

  The head lifting mechanism 70 moves the head unit 1 between the printing position and the retracted position by moving the head holder 3 and the cap mechanism 40 up and down. At the printing position, as shown in FIG. 1, the head unit 1 is located at the lower end of the movement range and faces the platen 5 at an interval suitable for printing. In the retracted position (see FIG. 8C), the head unit 1 is positioned at the upper end of the moving range and is largely separated from the platen 5. The wiping position (see FIG. 8B) is between the printing position and the retracted position. In the wiping position and the retracted position, wipers 81a and 81b, which will be described later, can move in the space between the head unit 1 and the platen 5.

  As shown in FIG. 8, the wiper unit (wiping mechanism) 80 wipes the four ejection surfaces 10a and the upper surface 5a of the platen 5 in the main scanning direction. Therefore, the wiper unit 80 includes two wipers 81a and 81b, and includes a base portion 82 and a wiper moving mechanism 83 that support the wipers. The wiper 81a is erected on the upper surface side of the base portion 82 and wipes the four ejection surfaces 10a. The wiper 81b is erected on the lower surface side of the base portion 82 and wipes the upper surface 5a. The wiper moving mechanism 83 includes a pair of guides 84 and a drive motor 80M. When the drive motor 80M is driven under the control of the control device 100, the base 82 reciprocates along the guide 84. As shown in FIG. 8A, the left end side of each head 10 is the standby position of the base 82. In any wiping operation, the wipers 81a and 81b wipe the surface while moving rightward in the figure. The return of the base 82 to the standby position is performed after the head unit 1 moves to the retracted position. As a modification, the wiper 81a may be configured so that the ejection surface 20a of the head 20 can also be wiped off.

  Next, the control device 100 will be described. The control device 100 controls the operation of each part of the printer and controls the operation of the entire printer 101. The control device 100 controls an image recording operation based on a recording command (image data or the like) supplied from an external device (such as a PC connected to the printer 101) 97. When receiving the recording command, the control device 100 drives the paper feed motor 34M for the paper feed roller 34 and the feed motors 35M to 39M for the feed roller pairs 35 to 39. The paper P delivered from the paper feed tray 33 is transported in the transport direction through the guides 61 to 64 while being sandwiched between the feed roller pairs 35 to 39. When the paper P passes under the four heads 10 while being supported by the upper surface 5a of the platen 5, the ink of each color is ejected from the ejection port 11 (see FIG. 2) toward the paper P under the control of the control device 100. The The ink ejection operation from the ejection port 11 is performed based on the detection signal output from the paper sensor 32. The paper P on which the image is formed is discharged to the paper discharge unit 31 through an opening formed in the upper portion of the housing 101a.

  In addition, the control device 100 recovers and maintains the ink ejection characteristics of the head 10 through a maintenance operation. The maintenance operation includes, for example, a purge or flushing operation, a wiping operation of the discharge surface 10a and the upper surface 5a of the platen 5, a capping operation, a humidifying operation, and the like.

  In the purge operation, all the pumps 10P are driven, and ink is forcibly discharged from all the ejection ports 11 of each head 10. At this time, the actuator is not driven. In the flushing operation, the actuator is driven and ink is ejected from all the ejection ports 11. The flushing operation is performed based on flushing data (data different from image data). In the wiping operation, the four ejection surfaces 10a are wiped by the wiper 81a, and the upper surface 5a of the platen 5 is wiped by the wiper 81b (see FIG. 8B). The wiping operation is performed after the purge operation, and residual ink and foreign matter on the ejection surface 10a are removed. The discharge characteristics of the discharge port 11 are restored, and the discharge surface 10a is cleaned. Note that the wiping operation of the upper surface 5a is performed even after the flushing operation is performed.

  In the capping operation, as shown in FIG. 4B, the cap 41 isolates the discharge space (the gap between the discharge surfaces 10a, 20a and the platen 5) S1 from the external space S2. Capping suppresses drying of the ink meniscus.

  The humidifying operation includes a resting humidifying operation during the capping operation and a humidifying operation during recording during the image recording operation. In the humidifying operation during the pause, as shown in FIG. 4B, a mist discharging operation is performed on the isolated discharge space S1. At this time, since the mist is filled in the discharge space S1, drying of all the discharge ports 11 of the four heads 10 is further suppressed. The humidifying operation during the pause is performed only during a predetermined period of the period during which the capping operation is performed. In the humidifying operation during recording, as shown in FIG. 4A, a mist discharging operation is performed on the discharge space S1 opened to the external space S2. At this time, the mist is supplied to all of the discharge ports 11 of the four heads 10, so that drying of the discharge ports 11 is suppressed. In the mist discharging operation, the plurality of actuators of the mist head 20 are driven and the mist is discharged from the discharge port 21.

  Next, the head 10 and the mist head 20 will be described in detail with reference to FIG. The four heads 10 have the same configuration and include a flow path unit 50, an actuator unit 51, and a COF (Chip On Film) 52, respectively.

  The flow path unit 50 is a laminated body in which rectangular metal plates 50a to 50i having substantially the same size are bonded to each other. In the flow channel unit 50, a flow channel reaching each discharge port 11 is formed. The flow path includes a common flow path 55 common to all the discharge ports 11 formed in the flow path unit 50 and an individual flow channel 56 provided for each discharge port 11. The individual flow path 56 is a flow path from the outlet of the common flow path 55 to the discharge port 11 via the aperture 56a and the pressure chamber 56b. The pressure chamber 56 b opens on the upper surface 50 a 1 of the flow path unit 50, and the discharge port 11 opens on the lower surface of the flow path unit 50. This lower surface corresponds to the ejection surface 10a. The plurality of pressure chambers 56b formed on the upper surface 50a1 constitutes one pressure chamber group.

  The actuator unit 51 is fixed to the upper surface 50a1 while covering the plurality of pressure chambers 56b constituting the pressure chamber group. The actuator unit 51 includes a plurality of actuators provided for each pressure chamber 56b.

  The COF 52 is fixed to the upper surface of the actuator unit 51. The COF 52 is a flat wiring board provided with a plurality of wirings, and a driver IC 52a (see FIG. 5) is mounted thereon. The plurality of wires of the COF 52 connect the control device 100 and the input terminal of the driver IC 52a, and the output terminal of the driver IC 52a and the electrode of the actuator.

  Under the control of the control device 100, a predetermined potential is applied to each actuator from the driver IC 52a, whereby the actuator is selectively driven. Thereby, ejection energy is given to the ink in the pressure chamber 56b.

  The mist head 20 has substantially the same configuration as the head 10 and includes a flow path unit 50, an actuator unit 51, and a COF 52, but the number of discharge ports 21, the number of individual flow paths 56, and the number of actuators. Are formed in two more than the head 10. That is, as shown in FIG. 2, the plurality of discharge ports 21 formed on the discharge surface 20a are formed one by one more on both sides in the main scanning direction than the plurality of discharge ports 11 formed on the discharge surface 10a. ing. The plurality of discharge ports 21 constitute a discharge port portion 25 through which mist is discharged. The discharge port portion (discharge port portion) 25 has a length equal to or longer than the interval between the two outermost discharge ports 11 in the main scanning direction, and is in the transport direction D with all the discharge ports 11 on each discharge surface 10a. Overlapping along. As a result, the mist is discharged from the discharge port portion 25, thereby making it possible to suppress drying of the ink in the vicinity of all the discharge ports 11. Further, the discharge port portion 25 has a plurality of divided regions 26 divided in the main scanning direction. These divided regions 26 are configured to correspond to one ejection port 21. In the mist head 20, the individual flow paths 56 and actuators formed more than the head 10 are formed corresponding to the discharge ports 21. In this configuration, a predetermined potential is applied to each actuator from the driver IC 52 a under the control of the control device 100, so that the actuator of the mist head 20 is selectively driven in the same manner as the head 10. Thereby, discharge energy is given to the water in the pressure chamber 56b.

  Next, the actuator unit 51 will be described in detail. As shown in FIG. 3B, two piezoelectric sheets 51b and 51c, a common electrode layer 51d, and one piezoelectric sheet 51a are included. A plurality of individual electrodes 51e are formed on the piezoelectric sheet 51a. The main part of the individual electrode 51e is in a region facing the pressure chamber 56b, and is connected to the land 51f outside this region. A signal from the driver IC 52a is given to the individual electrode 51e through the land 51f. In the actuator unit 51, a portion facing the pressure chamber 56b functions as an individual actuator.

  Here, a driving method of the actuator unit 51 for discharging droplets (ink droplets and water droplets) from the discharge port 11 of the head 10 and the discharge port 21 of the mist head 20 will be described. In the present embodiment, only the piezoelectric sheet 51a is polarized in the thickness direction. When an electric field in the polarization direction is applied between the electrodes 51d and 51e, the piezoelectric sheet 51a contracts in the surface direction. At this time, a strain difference is generated between the other piezoelectric sheets 51b and 51c. Since the piezoelectric sheet 51a is on the opposite side of the pressure chamber 56b with respect to the other piezoelectric sheets 51b and 51c, the actuator is unimorph-deformed into a convex shape toward the pressure chamber 56b. This deformation is used for ejecting droplets. Specifically, each actuator is in a convex deformation state in advance. In response to the discharge request, the actuator releases the deformation and returns to the deformed state again at the subsequent timing. The liquid is supplied to the pressure chamber 56b when the deformation is released, and one droplet is ejected when the deformation is restored. The time interval (pulse width) between the two timings is approximately equal to AL (Acoustic Length), and the pressure wave generated at each timing overlaps with the discharge under favorable conditions.

  When a mist-like water droplet is discharged from the discharge port 21 of the mist head 20, a mist signal is supplied to the individual electrode 51e. The mist signal is composed of a pulse having a voltage lower than that of the ink ejection signal, a pulse having a narrow pulse width, or a pulse having a wide pulse width. At this time, adjustment may be made in consideration of the viscosity difference between the ink and water. In either case, the water meniscus vibrates and very small water droplets (mist water droplets) are diffused. In the present embodiment, a narrow pulse width is adopted, and the pressure wave overlaps in a state that is out of favorable conditions for ejection. In the present embodiment, a mist signal including a voltage pulse whose pulse width exceeds the reference value and is narrower than AL is used.

  Next, the configuration of the head holder 3 and the cap mechanism 40 will be described with reference to FIG.

  The head holder 3 is a rigid frame-like frame made of metal or the like, and supports the side surface of the head unit 1 over the entire circumference. A cap 41 of a cap mechanism 40 is attached to the head holder 3. The contact portion between the head holder 3 and the head unit 1 is sealed with a sealant over the entire circumference. The contact portion between the head holder 3 and the cap 41 is also fixed with an adhesive over the entire circumference. The five heads 10 and 20 are also sealed with a sealant. Thereby, the cap 41 can make the discharge space S1 a sealed space.

  The cap mechanism 40 includes a cap 41 and a cap lifting mechanism 48 that lifts and lowers the cap 41. The cap (partition member) 41 can include the ejection space S1 together with the head unit 1 and is long in the main scanning direction. The cap 41 includes a lip member 42 and a diaphragm 44.

  The lip member 42 is made of a ring-shaped elastic material such as rubber, and includes a base portion 42x and a protruding portion 42a having a triangular cross section below the base portion 42x. A movable body 43 described later is fixed on the upper surface of the base portion 42x.

  The diaphragm 44 is also made of an annular elastic material such as rubber. The diaphragm 44 is a thin film member having flexibility, and an outer peripheral end (one end) is connected to the lip member 42. The inner peripheral end of the diaphragm 44 is a close contact portion 44a. The contact portion 44 a has an inner side surface that is in close contact with the side surface of the head unit 1, and an upper surface that is in close contact with the lower surface of the head holder 3. The upper surface of the contact portion 44a is fixed to the head holder 3 with an adhesive over the entire length.

  The cap lifting mechanism 48 includes a movable body 43, a plurality of gears 45, and a lifting motor 48M (see FIG. 5). The movable body 43 is made of an annular rigid material (for example, stainless steel) and surrounds the head unit 1. The movable body 43 is connected to a plurality of gears 45. When the lifting motor 48M is driven, the movable body 43 moves up and down as the gear 45 rotates.

  As the movable body 43 moves up and down, the lip member 42 is separated from the upper surface 5a from the contact position (the position shown in FIG. 4B) where the tip (projection 42a) contacts the upper surface 5a of the platen 5. The separation position (the position shown in FIG. 4A) is selectively taken. At the contact position, the discharge space S1 is in a sealed state (partitioned state). Thus, the platen 5 constitutes a part of the cap mechanism 40. Further, at the separation position, the discharge space S1 is open with respect to the external space S2.

  Next, the control device 100 will be described with reference to FIG. The control device 100 includes a CPU (Central Processing Unit) 91, a ROM (Read Only Memory) 92, a RAM (Random Access Memory) 93, an ASIC (Application Specific Integrated Circuit) 94, a flash memory 95, and the like. The ROM 92 stores a program executed by the CPU 91, various fixed data, nine unit waveforms (see FIG. 6), and the like. That is, the ROM 92 includes the waveform storage unit 110. The RAM 93 temporarily stores data (image data and the like) necessary for executing the program. That is, the RAM 93 includes the image data storage unit 111. The ASIC 94 includes a signal generation control circuit 115, a transport control circuit 116, and a maintenance control circuit 117. The ASIC 94 is connected to an external device 97 such as a PC (Personal Computer) via an input / output I / F (Interface) 96 so that data communication is possible.

  In the present embodiment, one CPU 91 performs processing related to various controls, but is not limited thereto. For example, a form in which a plurality of CPUs share processes related to various controls, a form in which an ASIC performs processes related to various controls, a process in which one or more CPUs and one or more ASICs cooperate, and processes related to various controls The form to perform etc. may be sufficient.

  The image data storage unit 111 stores image data (recording command) from the external device 97. The image data is a collection of dot data indicating the amount of liquid forming each pixel, and has a drive data format.

  The signal generation control circuit 115 includes a recording control circuit 121 and a mist control circuit 122. The recording control circuit 121 drives the actuator unit 51 of each head 10 based on the image data. Specifically, the drive data indicates whether the amount of ink ejected from each ejection port 11 in each recording cycle is in four stages (small, medium, large, or none). Here, “small amount” corresponds to a discharge waveform W1 described later, “medium amount” corresponds to a discharge waveform W2 described later, “large amount” corresponds to a discharge waveform W3 described later, and “none” will be described later. This corresponds to the non-ejection waveform W4 (all refer to FIG. 6).

  The waveform storage unit 110 stores nine unit waveforms (discharge waveforms W1, W2, W3, non-discharge waveform W4, and mist waveforms M1, M2, M3, M4, and M5) (see FIG. 6). The ejection waveforms W1 to W3 are unit waveforms for generating ejection signals for ejecting ink from the ejection ports 11. The non-ejection waveform W4 is a unit waveform for generating a non-ejection signal that does not cause ink to be ejected from the ejection port 11. The five mist waveforms M1 to M5 are unit waveforms for generating a mist signal for discharging mist from the discharge port 21. As the mist waveform M1 changes to the mist waveform M5, many mists are discharged from the discharge port 21. Let it drain. All of these nine unit waveforms have a time length corresponding to one recording cycle. One recording cycle corresponds to the time required for a sheet to be conveyed by a unit distance (minimum dot interval) corresponding to the recording resolution in the sub-scanning direction.

  The ejection signal, the non-ejection signal, and the mist signal are obtained by amplifying the above-described nine unit waveforms with the driver IC 52a, and the low level is a ground potential and the high level is a predetermined positive potential (for example, 24V). Such amplification is performed for each individual electrode 51e every recording period, and one amplification target waveform is selected from nine unit waveforms based on a discharge selection signal and a mist selection signal (described later).

  Further, the recording control circuit 121 outputs a discharge selection signal to the driver IC 52a based on the stored drive data. The ejection selection signal is output every recording cycle. From the driver IC 52a, one waveform (W1 to W4) having a positive positive high level is selected by the ejection selection signal and output to the individual electrode 51e as an ejection signal or a non-ejection signal.

  The transport control circuit 116 controls the paper feed motor 34M and the feed motors 35M to 39M so that the paper P is transported at a predetermined speed along the transport direction based on the image data (recording command). In the present embodiment, when monochrome printing is performed based on image data (recording command), the paper P is conveyed at a first predetermined speed, and when color printing is performed, the speed is slower than the first predetermined speed. The sheet P is conveyed at a second predetermined speed. The first and second predetermined speeds are speeds that can be moved by a unit distance in the recording resolution in the transport direction in one recording cycle.

  The maintenance control circuit 117 controls the lift motor 48M, the drive motor 80M, the head lift mechanism 70, and the pumps 10P and 20P in the maintenance operation.

  The flash memory 95 is a nonvolatile memory. The ejection port 11 from which ink was ejected based on the image data and the time at which the ink was ejected are stored in the flash memory 95 as ejection history information 112.

  The CPU 91 controls each component of the printer 101 while storing the processing result in the RAM 93 in accordance with a control program read from the ROM 92 and signals sent from various sensors. Further, the CPU 91 counts the time since ink is ejected from the ejection port 11, and calculates a rest time during which ink is not ejected continuously from the ejection port 11 based on the ejection history information 112. As described above, the CPU 91 includes a time calculation unit. Each pause time calculated by the CPU 91 is stored in the flash memory 95. That is, the flash memory 95 also serves as a storage unit that stores a pause time related to each discharge port 11. Further, the CPU 91 determines whether or not each calculated pause time exceeds a predetermined time.

  The mist control circuit 122 outputs a mist selection signal to the driver IC 52a during the recording period (period from the start to the end of recording on one sheet P) and during the maintenance operation. During the recording period (humidifying operation during recording), the mist selection signal is continuously output every recording period. From the driver IC 52a, one mist waveform (M1, M2, M3, M4, M5) having a positive high level is selected by the mist selection signal and is output to the individual electrode 51e as a mist signal. In the present embodiment, when color printing is performed based on image data, the mist control circuit 122 outputs to the driver IC 52a a mist selection signal for outputting the mist signal related to the mist waveform M3 to the individual electrode 51e. . On the other hand, when monochrome printing is performed based on the image data, the mist control circuit 122 outputs to the driver IC 52a a mist selection signal for outputting the mist signal related to the mist waveform M4 to the individual electrode 51e.

  Even during the maintenance operation (restoration humidification operation), the mist selection signal is output at every recording cycle, and continues for several seconds, for example, during the capping operation. During the maintenance operation, the mist control circuit 122 functions in cooperation with the maintenance control circuit 117. From the driver IC 52a, one mist waveform (M1, M2) with a positive high level and a predetermined potential is selected by the mist selection signal and output to the individual electrode 51e as the mist signal. In the present embodiment, the mist signal related to the mist waveform M2 is output to the individual electrode 51e related to the discharge port 21 on the downstream side of the center of the discharge surface 20a with respect to the wiping direction in which the discharge surface 10a is wiped by the wiper 81a. The mist control circuit 122 outputs the mist selection signal to the driver IC 52a. On the other hand, with respect to the wiping direction, the mist control circuit 122 provides a driver IC 52a with a mist selection signal for outputting a mist signal related to the mist waveform M1 to the individual electrode 51e associated with the discharge port 21 upstream of the center of the discharge surface 20a. Output to.

  In addition, the mist control circuit 122 outputs a mist signal related to the mist waveform M5 to the individual electrode 51e (actuator) related to the divided region 26 that overlaps with the ejection port 11 related to the rest time exceeding the predetermined time along the transport direction D. A mist selection signal is output to the driver IC 52a so as to be output. Further, the mist control circuit 122 applies either the mist waveform M3 or the mist waveform M4 to the individual electrode 51e related to the divided region 26 that overlaps with the ejection port 11 related to the rest time equal to or shorter than the predetermined time along the transport direction D. A mist selection signal is output to the driver IC 52a so that the mist signal is output. As a result, it is possible to supply a large amount of mist to the ejection ports 11 that have a small ink ejection amount (the ejection ports 11 related to the pause time exceeding a predetermined time). For this reason, it is possible to more effectively suppress ink drying of the ejection port 11.

  Next, a series of flow of the image recording operation and the maintenance operation executed by the control device 100 will be described with reference to FIG.

  First, the control device 100 waits for a recording command from the external device 97 (F1: NO). When receiving the recording command (F1: YES), the control device 100 stores the recording command (image data) in the RAM 93 and proceeds to step F2. . In step F2, capping cancellation is executed. That is, under the control of the maintenance control circuit 117, the lip member 42 moves from the contact position to the separation position.

  Next, in step F3, the CPU 91 determines whether the printing is monochrome printing or color printing. If monochrome printing (F3: YES), the process proceeds to step F4. If color printing (F3: NO), the process proceeds to step F5. Proceed to

  In Step F4, monochrome printing and a humidifying operation during recording are executed. That is, under the control of the conveyance control circuit 116, the paper P is conveyed from the paper supply tray 33 toward the paper discharge unit 31 at the first predetermined speed. Under the control of the recording control circuit 121, the head 10 that discharges black ink is driven. In this way, monochrome printing on the paper P is executed. At this time, under the control of the mist control circuit 122, a mist signal related to the mist waveform M4 is output to all the individual electrodes 51e of the mist head 20. Accordingly, the mist is discharged from the discharge port portion 25 (discharge port 21: divided region 26) of the mist head 20, and the humidifying operation during recording is executed. As shown in FIG. 4A, the mist flows along white arrows. The mist is moved by an air flow accompanying the conveyance of the paper P in this direction. More specifically, the mist discharged from the discharge port 21 flows in the paper transport direction D. That is, the mist flows toward the discharge port 11 that overlaps with the discharge port 21 that discharges the mist along the transport direction D. Thus, the mist from the mist head 20 is supplied to the vicinity of the discharge port 11 of each head 10 on the downstream side in the transport direction. For this reason, drying of the discharge port 11 can be suppressed even in an uncapped state. Accordingly, it is possible to suppress ink consumption due to a flushing operation or the like.

  In step F5, color printing and humidification operations during recording are executed. That is, the paper P is transported from the paper feed tray 33 toward the paper discharge unit 31 at the second predetermined speed under the control of the transport control circuit 116. Each head 10 is driven under the control of the recording control circuit 121. In this way, color printing on the paper P is executed. At this time, under the control of the mist control circuit 122, a mist signal related to the mist waveform M3 is output to all the individual electrodes 51e of the mist head 20. As a result, similarly to step F4, the mist is discharged from the discharge port portion 25 (discharge port 21: divided region 26) of the mist head 20, and the humidifying operation during recording is executed.

  In step F4 and step F5, the CPU 91 calculates the pause time of each discharge port 11 and stores it in the flash memory 95. Then, the CPU 91 determines whether or not the pause time related to each discharge port 11 stored in the flash memory 95 exceeds a predetermined time. Under the control of the mist control circuit 122, a mist signal related to the mist waveform M5 is outputted to the individual electrode 51e related to the divided region 26 of the mist head 20 that overlaps with the ejection port 11 where the pause time has exceeded. As a result, it is possible to increase the amount of mist supplied to the discharge port 11 that is easy to dry (those whose rest time has exceeded). For this reason, it is possible to more effectively suppress ink drying of the ejection port 11 with a small ink ejection amount.

  Next, in step F6, when the control device 100 receives the next recording command (F6: YES), the recording command (image data) is stored in the RAM 93, and the process returns to step F3. On the other hand, when the recording command is not received (F6: NO), the process proceeds to Step F7. In step F7, the process returns to step F6 until the predetermined time elapses (F7: NO), and when the predetermined time elapses (F7: YES), the process proceeds to step F8.

  In step F8, purge and wiping operations are executed. That is, the pumps 10P are driven by the control of the maintenance control circuit 117, and the ink is discharged from the ejection ports 11 of the heads 10 onto the platen 5 as shown in FIG. 8A (purge operation). When the purge operation is completed, the head unit 1 moves to the wiping position and the base 82 moves to the right in the figure as shown in FIG. 8B under the control of the maintenance control circuit 117. Accordingly, the four ejection surfaces 10a and the upper surface 5a of the platen 5 are wiped by the two wipers 81a and 81b (wiping operation). Thereafter, under the control of the maintenance control circuit 117, as shown in FIG. 8C, the head unit 1 moves to the retracted position, the base 82 moves to the left in the figure, and returns to the standby position. When the base 82 returns to the standby position, the head unit 1 moves to the printing position under the control of the maintenance control circuit 117.

  Next, in step F9, a capping and resting humidification operation is performed. That is, under the control of the maintenance control circuit 117, as shown in FIG. 4B, the lip member 42 is moved from the separation position to the contact position. In this way, the discharge space S1 is separated from the external space S2. After the capping is executed, the mist control circuit 122 controls the mist signal related to the mist waveform M2 to the individual electrode 51e related to the discharge port 21 on the downstream side of the center of the discharge surface 20a with respect to the wiping direction. A mist signal related to the mist waveform M1 is output to the individual electrode 51e related to the discharge port 21 upstream of the center of the surface 20a. Accordingly, the mist is discharged from the discharge port portion 25 (discharge port 21: divided region 26) of the mist head 20, and the humidifying operation during the pause is executed. In this way, when the mist is supplied in the paused partition state, the amount of moisture in the air in the discharge space S <b> 1 becomes high, and drying of the discharge port 11 can be suppressed. Further, when the ejection surface 10a is wiped with the wiper 81a, ink may remain on the downstream side of the ejection surface 10a in the wiping direction. When the residual ink is dried, the ink in the ejection port 11 near the residual ink is easily dried. However, since the amount of mist discharged per unit time from the discharge port 21 (divided region 26) on the downstream side in the wiping direction increases, the amount of moisture in the air on the downstream side in the wiping direction of the discharge space S1 increases and remains. Ink drying can be suppressed. For this reason, it becomes possible to suppress the drying acceleration of the ink at the ejection port 11 due to the drying of the residual ink.

  As described above, according to the present embodiment, when image recording on the paper P is performed, the mist is discharged from the discharge port portion 25, and the mist is discharged to the discharge space S1 facing the discharge surface 10a by the air flow generated by the conveyance of the paper P. Flowing into. At this time, the amount of mist discharged per unit time increases as the transport speed of the paper P increases. For this reason, the moisture content in the air of the discharge space S1 is maintained, and it becomes possible to suppress ink drying near the discharge port 11. As a result, ink discharge due to flushing or the like performed to suppress drying can be suppressed. Further, even if the plurality of heads 10 are provided, it is possible to suppress ink drying near the ejection ports 11.

  The mist head 20 has a plurality of actuators, and the plurality of actuators are individually driven to discharge the mist from each discharge port 21 (divided region 26). For this reason, it becomes possible to change the mist discharge | emission amount from each discharge outlet 21 with a comparatively simple structure.

  The amount of mist discharged per unit time in the humidifying operation during the pause is smaller than that in the humidifying operation during recording. For this reason, it becomes possible to suppress the consumption of the water for producing | generating mist.

  As a modification, a mist head 20 may be further provided between the heads 10 as shown in FIG. That is, the four mist heads 20 are disposed adjacent to the four heads 10 on the upstream side of the head 10 in the transport direction. Accordingly, the distance between the discharge port 21 of the mist head 20 adjacent to each other and the discharge port 11 of the head 10 is reduced, so that the mist discharged from the discharge port 21 is effectively supplied to the vicinity of the discharge port 11. For this reason, it is possible to effectively suppress ink drying in the vicinity of the ejection port 11 of each head 10.

  As another modification example, as shown in FIG. 10, the head unit 201 includes four unit heads 210, four unit mist heads 220, and a head holder 203 that supports these eight heads 210 and 220. It may be. The four unit heads 210 eject the same color ink. The four unit heads 210 are spaced apart from each other and are arranged in a staggered manner in the main scanning direction. Each unit head 210 has the same configuration as the head 10 described above. The four unit mist heads 220 are arranged in a staggered manner in the same manner as the four unit heads 210 on the upstream side in the transport direction of the unit heads 210, and are arranged adjacent to the unit heads 210, respectively. Each unit mist head 220 has the same configuration as that of the mist head 20 described above. Also in such a head unit 201, since the distance between the discharge port of the unit mist head 220 and the discharge port of the unit head 210 that are adjacent to each other is short, the mist discharged from the discharge port of the unit mist head 220 is the unit head. It is effectively supplied to the vicinity of the discharge outlet 210. For this reason, it is possible to effectively suppress ink drying in the vicinity of the ejection opening of each unit head 210.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. For example, in the above-described embodiment, four heads 10 are provided, but 1 to 3 or 5 or more may be provided. Further, the conveyance speed of the paper P in the above-described embodiment is faster in monochrome printing than in color printing, but may be reversed. Further, the conveyance speed of the paper P may be increased as the ink discharge amount from the head 10 to the paper P decreases. In this case, as the transport speed of the paper P increases, the mist discharge amount may be increased from a predetermined amount. By doing so, it is possible to obtain the same effect as the above-described embodiment.

  Further, the cap mechanism 40 may not be provided. In this case, the humidifying operation during the pause may not be performed. Further, the amount of mist discharged when performing the humidifying operation during pause may be equal to or greater than the humidifying operation during recording. Further, the mist heads 20 and 220 may have a simpler configuration than the heads 10 and 210. That is, the interval between the discharge ports of the mist heads 20 and 220 may be larger than the interval between the discharge ports of the heads 10 and 210. By doing so, the flow path configuration and the number of actuators in the mist heads 20 and 220 are reduced, and the configuration is simplified. Further, the mist heads 20 and 220 and the heads 10 and 220 may be configured integrally.

  The wiper unit 80 may not be provided. In this case, the same amount of mist may be discharged from each discharge port 21 in the humidifying operation during the pause.

  Further, as a cap mechanism capable of taking the discharge space S1 in a sealed state (partitioned state) and an open state, a cap having a bottom portion facing the discharge surfaces 10a and 20a and an annular portion standing on the periphery of the bottom portion; It may be configured to include a moving mechanism for moving the cap to a position where the tip of the annular portion contacts the peripheral edge of the lower surface (ejection surfaces 10a, 20a) of the entire head unit 1 and a position separated from the head unit 1. . In the above-described embodiment and modification, mist-like water is discharged from the mist heads 20 and 220. However, any liquid may be discharged as long as it is transparent and contains moisture.

  The present invention can be applied to both a line type and a serial type, and is not limited to a printer, and can also be applied to a facsimile machine, a copier, and the like. Further, recording is performed by discharging a liquid other than ink. The present invention can also be applied to a liquid ejection apparatus that performs the above. The recording medium is not limited to the paper P, and may be various recording media. Furthermore, the present invention can be applied regardless of the ink ejection method. For example, although a piezoelectric element is used in this embodiment, a resistance heating method or a capacitance method may be used.

4 Transport mechanism 5 Platen (opposing member)
10,210 Inkjet head (recording head)
10a Discharge surface 11 Discharge port 20,220 Mist head 20a Discharge surface (discharge surface)
21 Discharge port (discharge port)
25 Discharge port (discharge port)
26 Dividing area 40 Cap mechanism 41 Cap (partition member)
80 Wiper unit (wiping mechanism)
95 Flash memory (storage unit)
100 Control device (control means)
101 Printer (Liquid ejection device)
S1 Discharge space (gap)

Claims (13)

A transport mechanism for transporting the recording medium in the transport direction;
A recording head having a discharge surface in which a plurality of discharge ports for discharging a liquid to a recording medium are arranged at equal intervals along the longitudinal direction, with the direction orthogonal to the transport direction as the longitudinal direction;
A discharge port portion that extends in the longitudinal direction and is disposed upstream of the recording head in the transport direction and overlaps the plurality of discharge ports along the transport direction and discharges a transparent liquid mist is formed. A mist head having a discharge surface;
The plurality of discharge ports together with the opposing member, the discharge surface, and the discharge surface, with a facing member that can face the discharge surface and the discharge surface, and a gap between the counter member and the discharge surface and the discharge surface. And a partition member that includes the discharge port portion and partitions from the external space, and the partition member partitions the gap from the external space, and the partition member opens the clearance to the external space. A cap mechanism capable of taking a state; and
When the image recording on the recording medium is performed based on the recording command, the amount of liquid mist discharged from the discharge port unit per unit time increases as the recording medium conveyance speed increases. and control means for controlling the head includes a,
Wherein, when the gap of the partition state, to be less than when the emission amount of the liquid mist per unit time image recording is performed on the recording medium, that controls the mist head A liquid discharge apparatus characterized by that. Color ink is ejected from the plurality of ejection ports,
When the image recording is performed on the recording medium, if the image recording is monochrome printing, the control means is transported at a first predetermined speed, and if the image recording is color printing, The transport mechanism is configured such that the recording medium is transported at a second predetermined speed that is slower than the first predetermined speed, and that the amount of liquid mist discharged per unit time during the color printing is smaller than that during the monochrome printing. The liquid ejecting apparatus according to claim 1, wherein the mist head is controlled. A wiping mechanism for wiping the discharge surface along the longitudinal direction;
The mist head has a plurality of divided regions in which the discharge port portion is divided in the longitudinal direction, and the liquid mist is individually discharged from the plurality of divided regions,
When the gap is in the partitioned state, the control means has a larger amount of discharge of the liquid mist per unit time in the divided region on the downstream side with respect to the wiping direction in which the wiping mechanism wipes the ejection surface. The liquid ejection apparatus according to claim 1, wherein the mist head is controlled so as to be. A transport mechanism for transporting the recording medium in the transport direction;
A recording head having a discharge surface in which a plurality of discharge ports for discharging a liquid to a recording medium are arranged at equal intervals along the longitudinal direction, with the direction orthogonal to the transport direction as the longitudinal direction;
A discharge port portion that extends in the longitudinal direction and is disposed upstream of the recording head in the transport direction and overlaps the plurality of discharge ports along the transport direction and discharges a transparent liquid mist is formed. A mist head having a discharge surface;
The plurality of discharge ports together with the opposing member, the discharge surface, and the discharge surface, with a facing member that can face the discharge surface and the discharge surface, and a gap between the counter member and the discharge surface and the discharge surface. And a partition member that includes the discharge port portion and partitions from the external space, and the partition member partitions the gap from the external space, and the partition member opens the clearance to the external space. A cap mechanism capable of taking a state; and
A wiping mechanism for wiping the ejection surface along the longitudinal direction;
When the image recording on the recording medium is performed based on the recording command, the amount of liquid mist discharged from the discharge port unit per unit time increases as the recording medium conveyance speed increases. And a control means for controlling the head,
The mist head has a plurality of divided regions in which the discharge port portion is divided in the longitudinal direction, and the liquid mist is individually discharged from the plurality of divided regions,
When the gap is in the partitioned state, the control means has a larger amount of discharge of the liquid mist per unit time in the divided region on the downstream side with respect to the wiping direction in which the wiping mechanism wipes the ejection surface. The liquid ejecting apparatus is characterized by controlling the mist head. The control means is configured such that the discharge amount of the liquid mist per unit time from the divided region downstream of the center of the discharge surface with respect to the wiping direction is upstream of the center of the discharge surface with respect to the wiping direction. 5. The liquid ejection apparatus according to claim 3, wherein the mist head is controlled so as to be larger than a discharge amount of the liquid mist per unit time from the divided region. Before SL control means along said conveying direction, the more the divided areas overlapping the discharge amount of liquid discharged on the basis of the recording instruction is less the discharge port, the discharge amount of the liquid mist per unit time is much The liquid ejecting apparatus according to claim 3 , wherein the mist head is controlled so as to be. A storage unit that further stores, for each of the discharge ports, a downtime during which liquid is not continuously discharged from the discharge ports;
The control means is configured to reduce the pause time in which the discharge amount of the liquid mist per unit time from the divided region that overlaps the discharge port in the transport direction with respect to the pause time exceeding a predetermined time is equal to or less than the predetermined time. The liquid ejecting apparatus according to claim 6 , wherein the mist head is controlled so that the number of the mist heads is larger than that in the divided region that overlaps with the ejection port in the transport direction. The mist head includes the discharge surface in which a plurality of discharge ports for discharging the liquid mist are arranged along the longitudinal direction, a flow path unit having a plurality of individual flow paths reaching the discharge ports, and the individual flow. A plurality of actuators for applying discharge energy to the transparent liquid in the path,
The divided area is constituted by at least one of the discharge ports,
Wherein, when discharging the liquid mist from the plurality of divided regions, a liquid ejecting apparatus according to claim 6 or 7, wherein the controller controls the plurality of actuators. 9. The liquid ejection apparatus according to claim 1, wherein a length of the discharge port is equal to or greater than an interval between the two outermost ejection ports in the longitudinal direction. The liquid discharge apparatus according to claim 9, wherein both ends of the discharge port portion in the longitudinal direction are located outside the two discharge ports located on the outermost side with respect to the longitudinal direction. The discharge port portion is arranged along the longitudinal direction and includes a plurality of discharge ports from which the liquid mist is discharged.
The liquid ejection apparatus according to claim 10, wherein the two outermost discharge ports are located outside the two outermost discharge ports with respect to the longitudinal direction. A plurality of the recording heads are provided along the transport direction,
The plurality of recording heads eject inks of different colors,
The mist head, a liquid ejecting apparatus according to any one of claims 1 to 11, characterized in that it is arranged upstream of the recording head in the most upstream with respect to the transport direction. A plurality of the mist heads are provided,
The liquid ejecting apparatus according to claim 12 , wherein the plurality of mist heads are respectively disposed adjacent to the plurality of recording heads on the upstream side in the transport direction of the recording head.

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