JP6112159B2 - Liquid ejecting apparatus and liquid ejecting apparatus cleaning method - Google Patents

Description

The present invention relates to a liquid ejecting apparatus and a cleaning method for the liquid ejecting apparatus .

  As a fluid ejecting apparatus, an ink jet recording apparatus that ejects ink from a nozzle of an ejecting head onto a recording medium is known. In such an ink jet recording apparatus, the ejection speed and ejection amount of ink from the nozzles change with the passage of time, and the ink ejection state changes. For this reason, in order to maintain the ejection speed and ejection amount of ink within a desired range, a cleaning operation such as a flushing operation for periodically ejecting ink from the ejection head is performed (for example, see Patent Document 1).

JP 2003-43218 A

  However, since the above flushing operation is performed uniformly for all nozzles, there is a problem that ink is discharged from nozzles that do not require flushing, and the ink is wasted.

  In view of the circumstances as described above, it is an object of the present invention to provide a cleaning device and a liquid ejecting apparatus that can reduce liquid consumption in a cleaning operation.

The cleaning device according to the present invention is a liquid ejecting unit having an ejection surface provided with a plurality of nozzles for ejecting liquid onto a medium, and a cleaning device for maintaining the liquid ejecting unit, the belt capable of holding the liquid A support portion that is provided apart from the member in the longitudinal direction of the belt member and supports the belt member so that the belt member forms a facing portion that can face the ejection surface. A support portion having a pressing support portion that supports one end side, a lower support portion that supports the other end side of the opposing portion and is positioned below the pressing support portion in the direction of gravity, and the belt member in the longitudinal direction. A belt driving unit that is moved to the belt member, and a position adjacent to the belt member in a width direction that intersects the longitudinal direction of the belt member, and a state in which the liquid is ejected from the nozzle. A cleaning device having a detection unit capable of being taken out, a contact operation in which a portion of the opposed member of the belt member supported by the pressing support member is brought into contact with the ejection surface, and the opposed portion is disposed on the ejection surface. A control unit that performs a discharge operation of ejecting the liquid from the nozzle in a state of being opposed to each other , and the control unit has a portion that is supported by the pressing support unit of the belt member as the ejection surface. Are selectively brought into contact with a region including the defective nozzle detected by the detection unit .
Further, the pressing support portion is located upstream of the lower support portion in the moving direction of the belt member by the belt driving portion.
Further, the plurality of nozzles are provided so as to form a plurality of nozzle rows on the ejection surface, and in the cleaning device, the moving direction of the belt member in the facing portion is a direction along the nozzle rows. The controller is configured to execute the discharging operation while moving the belt member in the longitudinal direction.
Further, the control unit causes the liquid to be ejected from the nozzle, causes the detection unit to detect the ejection state, and then causes a portion of the belt member supported by the pressing support unit to contact the ejection surface.
Moreover, the said control part performs the said contact operation | movement after performing the said discharge operation | movement.
Further, the control unit executes the contact operation when the number of defective nozzles detected by the detection unit does not exceed a set threshold value, and when the number of defective nozzles exceeds a set threshold value, Execute the eject operation.
A cleaning method for a liquid ejecting apparatus according to the present invention includes a liquid ejecting unit having an ejecting surface provided with a plurality of nozzles for ejecting liquid onto a medium, a belt member capable of holding the liquid, and a longitudinal direction of the belt member A support portion that supports the belt member so as to form a facing portion that can be opposed to the jetting surface, and that supports one end side of the facing portion; A support portion having a lower side support portion that supports the other end side of the facing portion and is located below the pressing support portion in the direction of gravity, and the belt member in the width direction intersecting the longitudinal direction of the belt member And a detection unit capable of detecting the ejection state of the liquid ejected from the nozzle, the liquid ejecting the liquid from the nozzle. A region including a detection operation for detecting the ejection state to the detecting unit, a defective nozzle is detected by the detecting portion of the ejection surface portion supported on the pressing support portion of said opposing portion of said belt member And a discharge operation of ejecting the liquid from the nozzle in a state where the facing portion faces the ejection surface.
Thereby, the consumption of the liquid in the cleaning operation can be reduced.
The cleaning device according to the present invention is provided with a belt member capable of holding the liquid discharged from the nozzle formed on the ejection surface of the liquid ejection head, and spaced apart in the longitudinal direction of the belt member. A pair of support portions that support the belt member so as to form a facing portion that can face the ejection surface, a belt drive portion that moves the belt member in the longitudinal direction, and the belt drive of the pair of support portions An upstream support portion that supports an upstream side in the moving direction of the belt member by a portion, and a separation position where a portion of the opposed portion of the belt member that is supported by the upstream support portion is separated from the ejection surface. A support unit driving unit that moves between a contact position that contacts the ejection surface and a detection unit that can detect the ejection state of the liquid ejected from the nozzle for each nozzle, and The portion can receive the liquid ejected from the nozzle in a state in which the facing portion faces the ejection surface on the downstream side in the moving direction of the belt member from the portion supported by the upstream support portion. A receiving portion, and in a state in which the facing portion of the belt member is opposed to the ejection surface, the upstream support portion is moved, and a portion of the facing portion supported by the upstream support portion is A contact operation for contacting the ejection surface and a discharge operation for ejecting the liquid from the nozzle in a state where the facing portion is opposed to the ejection surface are performed.
The cleaning device is disposed to face an ejection surface on which a plurality of nozzles for ejecting liquid is formed in the liquid ejection head, and is separated from the belt member capable of holding the liquid in the longitudinal direction of the belt member. A pair of support portions that support the belt member; a pressing portion that presses a portion between the portions of the belt member supported by the pair of support portions toward the ejection surface; The detection unit capable of detecting the ejection state of the liquid by the nozzle for each nozzle, and the liquid of the defective nozzle in which the detection result of the detection unit among the plurality of nozzles is defective adheres to a part of the belt member And the angle of the adhering portion of the belt member to the liquid of the defective nozzle is constant in a state where the liquid of the defective nozzle and a part of the belt member are adhered. Serial and a control unit for controlling the position of the pair of support portions.

  According to the present invention, it is possible to selectively perform a cleaning operation on a defective nozzle by adhering the liquid of the defective nozzle whose detection result of the detection unit is defective among the plurality of nozzles to the granular member. Thereby, the consumption of the liquid in the cleaning operation can be reduced. Further, since a cleaning operation is not performed on a normal nozzle that does not require a cleaning operation, it is possible to avoid a so-called induced omission that removes liquid from such a normal nozzle. In addition, in the present invention, the position of the pair of support portions is controlled so that the angle of the adhering portion of the belt member is constant while the belt member is partially attached to the defective nozzle. On the other hand, it is possible to suppress variations in the attachment conditions of the belt member. Thereby, stable cleaning can be performed.

  In addition, as a specific aspect for “adhering the liquid of the defective nozzle to a part of the belt member”, for example, an aspect in which a part of the belt member is brought into contact with the defective nozzle, the belt member is in contact with the liquid swelled from the defective nozzle. And a mode in which a part of the belt member is brought into contact with the ejection surface in the vicinity of the defective nozzle.

  More specifically, a mode in which a part of the belt member is brought into contact with the defective nozzle includes a mode in which the belt member is inserted into the defective nozzle, a mode in which the opening of the defective nozzle is blocked by a part of the belt member, and the like. . In this case, by bringing a part of the belt member into direct contact with the defective nozzle, it is possible to scrape off the foreign material or liquid adhering to the defective nozzle and physically remove the foreign material or liquid.

  Further, the mode in which a part of the belt member is brought into contact with the liquid swelled from the defective nozzle does not directly contact a part of the belt member with the defective nozzle. By absorbing the liquid by the belt member, a flow in which the liquid is discharged can be formed in the defective nozzle. By this flow, the foreign matter in the defective nozzle is pushed out, and clogging of the defective nozzle can be eliminated.

  Further, in the aspect in which a part of the belt member is brought into contact with the ejection surface in the vicinity of the defective nozzle, when the foreign material is attached to the ejection surface in the vicinity of the defective nozzle, the foreign material is wiped with a part of the belt member. Can be removed.

The cleaning device further includes a belt driving unit that moves the belt member in the longitudinal direction, and the control unit presses the belt in a state where a part of the belt member is pressed toward the ejection surface by the pressing unit. It is preferable to control the belt drive unit so that the member moves.
According to the present invention, since the belt member can be moved in a state in which a part of the belt member is pressed toward the ejection surface by the pressing portion, an unused clean portion of the belt member is removed from the defective nozzle. Can be contacted.

In the cleaning device, one support portion that supports the downstream side in the moving direction of the belt member by the belt driving portion of the pair of support portions is disposed below the pressing portion in the gravity direction. Preferably it is.
According to the present invention, since the one support portion that supports the downstream side in the moving direction of the belt member by the belt driving portion among the pair of support portions is disposed below the pressing portion in the gravity direction, the belt member Of these, the used part moves along the direction of gravity. For this reason, it can prevent that a liquid adheres again with respect to an ejection surface etc. from the part to which the liquid adhered among belt members.

In the cleaning device, it is preferable that a portion of the pressing portion that contacts the belt member is formed to be rotatable.
According to this invention, since the part which contacts a belt member among the press parts is formed so that rotation is possible, the friction which generate | occur | produces between a press part and a belt member can be reduced. Accordingly, the belt member can be smoothly moved in a state where the pressing portion and the belt member are in contact with each other.

In the cleaning device, it is preferable that a portion of the pair of support portions that contacts the belt member is formed to be rotatable.
According to the present invention, since the portion of the pair of support portions that contacts the belt member is formed to be rotatable, friction generated between the pair of support portions and the belt member can be reduced. Thereby, the belt member can be smoothly moved in a state where the pair of support portions support the belt member.

It is preferable that the cleaning device further includes a pressing unit driving unit that integrally moves the pressing unit and the support unit along the ejection surface.
According to the present invention, since the pressing unit driving unit that moves the pressing unit and the supporting unit integrally along the ejection surface is further provided, the belt member is held while maintaining the positional relationship between the pressing unit and the supporting unit. Can be moved. Thereby, adjustment of the angle in the contact position of a belt member can be performed more smoothly.

A liquid ejecting apparatus according to the present invention is a liquid ejecting unit having an ejecting surface provided such that a plurality of nozzles ejecting liquid onto a medium form a plurality of nozzle rows, and a cleaning device that maintains the liquid ejecting unit. A belt member capable of holding the liquid and spaced apart in the longitudinal direction of the belt member, the belt member supporting the belt member so as to form a facing portion that can face the ejection surface. A pair of support portions; a belt drive portion that moves the belt member in the longitudinal direction; and an upstream support portion that supports an upstream side in the moving direction of the belt member by the belt drive portion of the pair of support portions. A portion of the opposed portion of the belt member that is supported by the upstream support portion is moved between a separated position separated from the ejection surface and a contact position contacting the ejection surface. A cleaning device having a drive unit, a detection unit capable of detecting the ejection state of the liquid ejected from the nozzle for each nozzle, and a state in which the facing part of the belt member is opposed to the ejection surface In the state where the upstream support portion is moved to bring the portion of the facing portion supported by the upstream support portion into contact with the ejection surface, and the facing portion is opposed to the ejection surface. And a control unit that performs a discharge operation of ejecting the liquid from the nozzle.
The liquid ejecting apparatus includes: a liquid ejecting head having an ejecting surface on which a plurality of nozzles ejecting liquid are formed; and a cleaning device that cleans the liquid ejecting head in contact with the ejecting surface. As the device, the above-described cleaning device is used.

  According to the present invention, since it is possible to reduce the amount of liquid consumption required for the cleaning operation, it is possible to obtain a liquid ejecting apparatus capable of reducing running costs.

1 is a diagram illustrating a schematic configuration of a printing apparatus according to an embodiment of the present invention. The top view which shows the structure of a head. The figure which shows the structure of a cleaning apparatus. The figure which shows the structure of a part of cleaning apparatus. The schematic diagram which shows the structure of a detection part. The figure which shows an example of the detection operation by a detection part. The graph which shows an example of the detection result by a detection part. FIG. 3 is a block diagram illustrating a configuration of a control system of the printing apparatus. The figure which shows an example of cleaning operation | movement. The figure which shows an example of cleaning operation | movement. The figure which shows an example of cleaning operation | movement. The figure which shows the other example of cleaning operation | movement.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating a schematic configuration of a printing apparatus PRT (liquid ejecting apparatus) according to the present embodiment. In the present embodiment, an ink jet printing apparatus will be described as an example of the printing apparatus PRT.

  A printing apparatus PRT shown in FIG. 1 is an apparatus that performs a printing process while conveying a sheet-like medium M such as paper or a plastic sheet. The printing apparatus PRT includes a housing PB, an inkjet mechanism IJ that ejects ink onto the medium M, an ink supply mechanism IS that supplies ink to the inkjet mechanism IJ, a transport mechanism CV that transports the medium M, and an inkjet mechanism IJ. The maintenance mechanism MN that performs the maintenance operation of the above and the control device CONT that controls these mechanisms.

  Hereinafter, an XYZ rectangular coordinate system is set, and the positional relationship of each component will be described with reference to the XYZ rectangular coordinate system as appropriate. In this embodiment, the transport direction of the medium M is the X direction, the direction perpendicular to the X direction on the transport surface of the medium M is the Y direction, and the direction perpendicular to the plane including the X axis and the Y axis is the Z direction. To do. The rotation direction around the X axis is the θX direction, the rotation direction around the Y axis is the θY direction, and the rotation direction around the Z axis is the θZ direction.

  The housing PB is formed so that the Y direction is the longitudinal direction. Each part of the inkjet mechanism IJ, the ink supply mechanism IS, the transport mechanism CV, the maintenance mechanism MN, and the control device CONT is attached to the housing PB. A platen 13 is provided in the housing PB. The platen 13 is a support member that supports the medium M. The platen 13 is disposed in the central portion in the X direction of the housing PB. The platen 13 has a flat surface 13a oriented in the + Z direction. The flat surface 13a is used as a support surface that supports the medium M.

  The transport mechanism CV includes a transport roller and a motor that drives the transport roller. The transport mechanism CV transports the medium M into the housing PB from the −X side of the housing PB and discharges the medium M from the + X side of the housing PB to the outside of the housing PB. The transport mechanism CV transports the medium M so that the medium M passes over the platen 13 inside the housing PB. In the transport mechanism CV, the transport timing, transport amount, and the like are controlled by the control device CONT.

  The inkjet mechanism IJ has a head H that ejects ink and a head moving mechanism AC that holds and moves the head H. The head H ejects ink toward the medium M sent onto the platen 13. The head H has an ejection surface Ha that ejects ink. The ejection surface Ha is directed in the Z direction and is disposed so as to face the support surface 13a of the platen 13. The ejection surface Ha is formed of a metal plate material such as stainless steel.

FIG. 2 is a diagram illustrating a configuration when the head H is viewed from the −Z side.
As shown in FIG. 2, a plurality of nozzles NZ are formed on the ejection surface Ha. On the ejection surface Ha, a plurality of nozzle rows L parallel to the transport direction (X direction) of the medium M are formed by the plurality of nozzles NZ. In the present embodiment, four nozzle rows L (L1 to L4) are formed.

  Returning to FIG. 1, the head moving mechanism AC has a carriage CA. The head H is fixed to the carriage CA. The carriage CA is in contact with a guide shaft 8 that extends in the longitudinal direction (Y direction) of the housing PB. The head H and the carriage CA are arranged in the + Z direction of the platen 13.

  In addition to the carriage CA, the head moving mechanism AC includes a pulse motor 9, a drive pulley 10 that is rotationally driven by the pulse motor 9, and the drive pulley 10 that is provided on the opposite side in the width direction of the printer body 5. It has a pulley 11 and a timing belt 12 that is stretched between the driving pulley 10 and the idle pulley 11 and connected to the carriage CA.

  The carriage CA is connected to the timing belt 12. The carriage CA is provided to be movable in the Y direction as the timing belt 12 rotates. When moving in the Y direction, the carriage CA is guided by the guide shaft 8.

  The ink supply mechanism IS supplies ink to the head H. A plurality of ink cartridges CTR are accommodated in the ink supply mechanism IS. The printing apparatus PRT of the present embodiment has a configuration (off-carriage type) in which the ink cartridge CTR is accommodated at a position different from the head H. The ink supply mechanism IS has a supply tube TB that connects the head H and the ink cartridge CTR. The ink supply mechanism IS has a pump mechanism (not shown) that supplies the ink stored in the ink cartridge CTR to the head H via the supply tube TB.

  The maintenance mechanism MN is disposed at the home position of the head H. This home position is set in an area outside the area where printing is performed on the medium M. In the present embodiment, the home position is set on the + Y side of the platen 13. The home position is a place where the head H stands by when the printing apparatus PRT is powered off or when recording is not performed for a long time.

  The maintenance mechanism MN has a capping mechanism CP that covers the ejection surface Ha. The capping mechanism CP has a cap member 50 formed in a tray shape. Further, the maintenance mechanism MN has a cleaning device CL that performs a cleaning operation of the head H. In addition, the maintenance mechanism MN has a wiping mechanism (not shown) that wipes the ejection surface Ha.

FIG. 3 is a side view showing a partial configuration of the cleaning device CL.
As shown in FIGS. 1 and 3, the cleaning device CL includes a belt member 31, a belt guide part 32, a pressing part 33, and a detection part 34. The cleaning device CL is arranged side by side with the capping mechanism CP.

The belt member 31 is made of a flexible material that can absorb ink.
Examples of such a material include polyester and a mixture of polyester and nylon. More specifically, ESM-3506 manufactured by Shinano Kakko, Krausen W023 manufactured by KB Seiren, 73001TR (MK type), 57120TF (BS type) manufactured by Toray, and the like can be mentioned. The belt member 31 is fed out or wound up by the belt driving unit 30.

The belt drive unit 30 includes a feed roller 30a, a take-up roller 30b, and a roller drive unit (pressing unit drive unit) 30c. The belt member 31 is wound in a roll shape around each of the feed roller 30a and the take-up roller 30b.
The roller drive unit 30c rotates the feed roller 30a and the take-up roller 30b. The belt member 31 is fed from the feed roller 30a by the driving of the roller drive unit 30c, and is taken up by the take-up roller 30b via the guide roller 32a and the guide roller 32b (a pair of support units) of the belt guide unit 32. It is done.

The belt guide portion 32 includes the guide rollers 32a and 32b and the roller driving portion 32c.
The guide rollers 32a and 32b are formed in a cylindrical shape or a columnar shape, for example, and are provided to be rotatable in the circumferential direction. The guide rollers 32a and 32b are arranged so that the rotation axis is along the Y direction. Specifically, the guide rollers 32a and 32b are arranged in a state where the rotation axis has an inclination of, for example, 5 ° or less with respect to the Y direction. An example of the arrangement of the guide rollers 32a and 32b includes a case where at least one of the guide rollers 32a and 32b is parallel to the Y axis.

  The guide rollers 32a and 32b are driven rollers. The guide roller 32a and the guide roller 32b are integrally fixed by, for example, a frame FL1. For this reason, the positional relationship in the X direction, the Y direction, and the Z direction is fixed between the guide roller 32a and the guide roller 32b.

  The pressing part 33 has a pressing roller 33a. The pressing roller 33a is formed, for example, in a cylindrical shape or a columnar shape, and is provided to be rotatable in the circumferential direction. The pressing roller 33a is arranged so that the rotation axis is along the Y direction. Specifically, the pressing roller 33a is arranged in a state where the rotation axis has an inclination of, for example, 5 ° or less with respect to the Y direction. An example of the arrangement of the pressing roller 33a includes a case where the rotation axis of the pressing roller 33a is parallel to the Y axis.

  The pressing roller 33a supports a portion between the portions of the belt member 31 supported by the guide roller 32a and the guide roller 32b. A portion of the belt member 31 that is hung on the pressing roller 33a is a facing portion 31a that faces the head H.

  The pressing roller 33a is fixed integrally with the guide roller 32a by a frame FL2. Therefore, the pressing roller 33a, the guide roller 32a, and the guide roller 32b are integrally formed, and their positional relationships in the X direction, the Y direction, and the Z direction are fixed. For this reason, the belt member 31 is kept in a state where the angle θ of the portion hung on the pressing roller 33a is constant. In addition, the guide roller 32b is arrange | positioned rather than the press roller 33a at -Z side (front of a gravitational direction).

FIG. 4 is an enlarged view showing the configuration of the pressing roller 33a. In the following description, in order to describe the configuration of the pressing roller 33a in comparison with a configuration of a part of the head H, a configuration of a part of the head H is shown in FIG.
As shown in FIG. 4, the pressing roller 33 a is a part that contacts the belt member 31. The pressing roller 33a is formed in a disk shape having a diameter R1, for example. The pressure roller 33a is formed such that the diameter R1 of the pressure roller 33a is smaller than the pitch P1 of the nozzles NZ in the nozzle row L.

  As shown in FIG. 3, the roller drive part 32c among the belt guide parts 32 is connected to the guide roller 32a. The roller driving unit 32c includes an actuator (not shown) that moves the guide roller 32a in the X direction, the Y direction, and the Z direction. The guide roller 32a is provided integrally with the guide roller 32b and the pressing roller 33a by the frame FL1 and the frame FL2. Therefore, the guide roller 32a is moved in the X direction, the Y direction, and the Z direction by the roller driving unit 32c, so that the guide roller 32a, the guide roller 32b, and the pressing roller 33a are integrated in the X direction, the Y direction, and the Z direction, respectively. Moving. The drive amount and drive timing of the roller drive unit 32c are controlled by the control device CONT.

  When the guide roller 32a, the guide roller 32b, and the pressing roller 33a move to the + Z side, a portion of the belt member 31 that is hung on the pressing roller 33a moves to the head H side. The portion of the belt member 31 that is hung on the pressing roller 33a moves to a position where it contacts the ejection surface Ha of the head H while keeping the winding angle θ constant (see the chain line portion in FIG. 3).

  As described above, the arrangement of the pressing roller 33a in the XY direction is adjusted by the roller driving unit 32c, and the pressing roller 33a is moved to the + Z side, whereby the belt member 31 is moved to a desired position in the XY direction on the ejection surface Ha. Can be brought into contact with each other. As shown in FIG. 4, in this embodiment, since the diameter R1 of the pressing roller 33a is smaller than the pitch P1 of the nozzles NZ in the nozzle row L, a part of the belt member 31 is brought into contact with each nozzle NZ individually. be able to.

  In addition, when the material of said belt member 31 is used, thickness t1 (refer FIG. 4) of the belt member 31 can be about 200 micrometers-300 micrometers, for example. In the configuration shown in FIG. 4, the pitch P1 of the nozzles NZ is about 100 μm, the diameter of the nozzles NZ is about 20 μm, the thickness t1 of the belt member 31 is about 200 μm, and the diameter R1 of the pressing roller 33a is about 300 μm. However, each of the above numerical values is merely an example, and the same description can be made even when other values are taken.

The detection unit 34 detects the ink ejection state of the plurality of nozzles NZ for each nozzle NZ.
FIG. 5 is a schematic diagram illustrating the configuration of the detection unit 34. As shown in FIG. 5, the detection unit 34 includes an ink droplet sensor 80. The ink droplet sensor 80 charges ink droplets ejected from the nozzles of the head H, and outputs a voltage change based on electrostatic induction when the charged ink droplet D flies as a detection signal. It is a sensor configured to be able to grasp the discharge state.

  The ink droplet sensor 80 is disposed so as to face the ejection surface Ha of the head H via a predetermined gap. The ink droplet sensor 80 includes an ink droplet detection device 76 and a processing device 82.

  The ink droplet detection device 76 has a detection electrode 79 provided in the capping mechanism CP. An ink absorber 77 is provided inside the cap member 50. The ink absorber 77 is formed of a sponge-like member capable of holding (absorbing) the ink D, a porous member, or the like. The detection electrode 79 is provided on the surface of the ink absorber 77 on the + Z side. A suction pump 17 (not shown) is connected to the bottom of the cap member 50. The ink droplet D absorbed by the ink absorber 77 is sucked by the suction pump 17 and discharged to the outside.

  The detection electrode 79 is formed of a metal mesh member such as stainless steel. A detection surface 78 is formed on the surface of the detection electrode 79 on the + Z side. The detection surface 78 is disposed at a position on the −Z side with respect to the + Z side end surface of the cap member 50.

  The ink droplet detection device 76 includes a voltage applicator 75 that applies a voltage between the detection surface 78 and the ejection surface Ha of the head H, and a voltage detector 81 that detects the voltage of the detection surface 78. . The voltage applicator 75 electrically connects the detection electrode 79 and the ejection surface Ha via a DC power source and a resistance element so that the detection electrode 79 becomes a positive electrode and the ejection surface Ha becomes a negative electrode.

  In the present embodiment, since the ejection surface Ha is formed of a plate material such as stainless steel and the detection electrode 79 is formed of a metal such as stainless steel, each of the ejection surface Ha and the detection electrode 79 has conductivity. It is a configuration. For this reason, the voltage applicator 75 can apply a voltage between the ejection surface Ha and the detection surface 78.

  The voltage detector 81 integrates and outputs the voltage signal of the detection electrode 79, an inverting amplifier circuit that inverts and amplifies the signal output from the integration circuit, and an output from the inverting amplifier circuit. An A / D conversion circuit for A / D converting and outputting the received signal.

  The ink droplet D ejected from the nozzle NZ and landed on the detection surface 78 passes through the gap between the grid-shaped detection electrodes 79 and is held (absorbed) by the ink absorber 77 disposed on the lower side. The configuration of the detection electrode 79 is not limited to the mesh member as long as it can pass the ink droplet D ejected from the nozzle NZ to the ink absorber 77 side, and other configurations may be used.

  The ink droplet detection device 76 applies an electric field between the ejection surface Ha and the detection surface 78 to detect a temporal change in voltage value based on electrostatic induction when ink moves from the nozzle NZ to the detection surface 78. To the processing device 82. The processing device 82 can process the output of the ink droplet detection device 76 and can acquire information on the weight of the ink based on the detection waveform output from the ink droplet detection device 76. Then, the acquired information is output to the control device CONT.

  Next, the principle of the ink droplet sensor 80, that is, the principle that an induced voltage is generated by electrostatic induction will be described with reference to the drawings. FIG. 6A and FIG. 6B are schematic diagrams for explaining the principle that an induced voltage is generated by electrostatic induction. FIG. 6A shows a state immediately after the ink droplet D is ejected, and FIG. 6B shows a state where the ink droplet D has landed on the inspection region 74 of the cap member 50. FIG. 7 is a diagram illustrating an example of a waveform of a detection signal (for one drop of ink) output from the ink drop sensor 80.

  First, an ink droplet D is ejected from any one nozzle NZ in a state where a voltage is applied between the ejection surface Ha and the detection electrode 79. At this time, since the ejection surface Ha is a negative electrode, as shown in FIG. 6A, some negative charges on the ejection surface Ha move to the ink droplet D, and the ejected ink droplet D becomes negative. Charges up. As the ink droplet D approaches the detection surface 78 of the cap member 50, the positive charge increases on the surface of the detection electrode 79 due to electrostatic induction. Thereby, the voltage between the ejection surface Ha and the detection electrode 79 becomes higher than the initial voltage value in a state where the ink droplet D is not ejected due to the induced voltage generated by electrostatic induction.

  Thereafter, as shown in FIG. 6B, when the ink droplet D lands on the detection electrode 79, the positive charge of the detection electrode 79 is neutralized by the negative charge of the ink droplet D. For this reason, the voltage between the ejection surface Ha and the detection electrode 79 is lower than the initial voltage value. Thereafter, the voltage between the ejection surface Ha and the detection electrode 79 returns to the initial voltage value.

  Therefore, as shown in FIG. 7, the detection waveform output from the ink drop sensor 80 is a waveform that once rises, then falls to below the initial voltage value, and then returns to the original voltage value. In this manner, the ink droplet sensor 80 detects a voltage change when the ink droplet D is ejected from each nozzle NZ.

However, for example, when the ink droplet D is thickened, the ejection amount is reduced compared to the normal amount.
For this reason, as shown by the solid line in FIG. 7, the amplitude A of the detection signal (detection waveform Z) output from the ink droplet sensor 80 is the amplitude of the detection signal at the normal time (ideal waveform Z0: broken line in FIG. 7). It becomes smaller than A0 (amplitude difference ΔA). In addition, the time from when the ejection pulse DP is applied until the ink droplet D is separated from the ejection surface Ha is also delayed compared to the normal time (the timing at which the voltage rises is shifted by the time difference ΔT).

  Therefore, the ink D in each nozzle NZ of the head H is compared by comparing the amplitude A of the detection waveform Z output from the ink droplet sensor 80 and the voltage rise timing with those of the ideal waveform Z0 (detecting ΔA and ΔT). Can be obtained. Further, in a state where the viscosity of the ink is increased, the ink cannot be discharged from the nozzle NZ satisfactorily, resulting in a defective nozzle. In this state, no ink is ejected, so no waveform is detected. That is, as described above, the ink droplet sensor 80 can detect the ink ejection status (determining whether or not it is a defective nozzle) at each nozzle NZ.

FIG. 8 is a block diagram showing an electrical configuration of the printing apparatus PRT.
The control device CONT is connected to an input device IP for inputting various information relating to the operation of the printing device PRT, a storage device MR storing various information relating to the operation of the printing device PRT, and the like. A moving mechanism AC, a maintenance mechanism MN, and the like are connected. The control device CONT can control the capping mechanism CP of the maintenance mechanism MN, the cleaning device CL including the belt guide portion 32, the pressing portion 33, and the detection portion 34 (ink droplet sensor 80).

  The printing apparatus PRT includes a drive signal generator 62 that generates a drive signal to be input to the piezoelectric vibrator 38 provided for each nozzle NZ. The drive signal generator 62 is connected to the control device CONT. The drive signal generator 62 receives data indicating the amount of change in the voltage value of the ejection pulse input to the piezoelectric vibrator 38 of the head H, and a timing signal that defines the timing for changing the voltage of the ejection pulse. The drive signal generator 62 is provided so that a drive signal can be individually supplied to each piezoelectric vibrator 38.

Next, the operation of the printing apparatus PRT configured as described above will be described.
When performing the printing operation by the head H, the control device CONT arranges the medium M on the −Z side of the head H by the transport mechanism CV. After disposing the medium M, the controller CONT inputs a drive signal from the drive signal generator 62 associated with the nozzle NZ to the piezoelectric vibrator 38 based on the image data of the image to be printed while moving the head H. When a drive signal is input to the piezoelectric vibrator 38, the piezoelectric vibrator 38 expands and contracts and ink is ejected from the nozzle NZ. A desired image is formed on the medium M by the ink ejected from the nozzles NZ.

  As time elapses, the viscosity of the ink increases, and the ejection speed and ejection amount of the ink may decrease, resulting in ejection failure. Therefore, the control device CONT periodically performs the cleaning operation of the nozzle NZ.

  As a cleaning operation, the control device CONT first performs a detection step of detecting, for each nozzle NZ, the ink ejection state from the plurality of nozzles NZ. As shown in FIG. 9, the control device CONT arranges the head H on the + Z side of the capping mechanism CP, ejects ink from each nozzle NZ, and then the defective nozzle EN in which thickening or omission is recognized by the detection unit 34. Is detected.

  After the detection step, the control device CONT arranges the ejection surface Ha of the head H so as to face the facing portion 31a of the belt member 31. Thereafter, the control device CONT performs a pressing step of moving the portion of the belt member 31 that is hung on the pressing roller 33a toward the defective nozzle EN. In the pressing step, the control device CONT adheres a part of the belt member 31 to the ink D of the defective nozzle EN.

  As a specific aspect, an aspect in which the facing portion 31a is brought into contact with the defective nozzle EN can be mentioned. In this case, for example, a mode in which the facing portion 31a is inserted into the defective nozzle EN can be used. In the following description, a mode in which the facing portion 31a is inserted into the defective nozzle EN is taken as an example.

In this case, the control device CONT first moves the pressing roller 33a to a position equal to the position in the X direction and the position in the Y direction of the defective nozzle EN by the roller driving unit 32c.
In this state, the control device CONT moves the pressing roller 33a in the + Z direction by the roller driving unit 32c as shown in FIG. By this movement, the pressing roller 33a disposed at the + Z side tip of the pressing roller 33a presses the facing portion 31a, and the facing portion 31a contacts the defective nozzle EN.

  The control device CONT moves the pressing roller 33a further to the + Z side, so that the facing portion 31a enters the defective nozzle EN. The control device CONT causes the facing portion 31a to enter the defective nozzle EN up to a position where the facing portion 31a contacts the ink held by the defective nozzle EN.

  In this state, the ink retained in the defective nozzle EN is absorbed by the facing portion 31a. The thickened ink in the defective nozzle EN is thus absorbed by the facing portion 31a. Further, when there is a foreign substance in the defective nozzle EN, it is discharged along the ink flow and removed to the outside of the nozzle. In this way, since the thickening or clogging of the defective nozzle EN is eliminated, the defective nozzle EN returns to a state in which there is no problem in the ejection state. When a defective nozzle EN is detected across a plurality of nozzle rows L, for example, the contact operation of the facing portion 31a of the belt member 31 may be performed for each nozzle row L.

  Further, the control device CONT brings the belt member 31 into contact with the defective nozzle EN, and then moves the pressing roller 33a to the −Z side by the roller driving unit 32c to release the contact state of the belt member 31. After the belt member 31 is separated from the defective nozzle EN, the control device CONT moves the head H and the pressing roller 33a relative to each other in the X direction (or Y direction), for example, as shown in FIG. The facing portion 31a is made to face another defective nozzle EN among the nozzles NZ. Thereafter, the control device CONT can bring the facing portion 31a into contact with another defective nozzle EN by moving the pressing roller 33a in the + Z direction. In this way, the control device CONT does not perform the cleaning operation on the whole of the plurality of nozzles NZ, but selectively performs the cleaning operation on the defective nozzles EN, so that the nozzles having no problem in the ejection state are obtained. In contrast, the cleaning operation can be avoided.

  In the pressing step, the facing portion 31a of the belt member 31 is supported by the pressing roller 33a. A pair of portions of the belt member 31 that sandwich the facing portion 31a in the longitudinal direction of the belt member 31 are supported by the guide roller 32a and the guide roller 32b. As described above, the pressing step is performed in a state where the upstream side and the downstream side of the facing portion 31a are supported by the guide roller 32a and the guide roller 32b.

  In the above configuration, the pressing roller 33a, the guide roller 32a, and the guide roller 32b are fixed by the frames F1 and F2. Therefore, as shown in FIG. 10, in the state where the facing portion 31a of the belt member 31 is in contact with the defective nozzle EN, the angle θ of the facing portion 31a of the belt member 31 is adjusted to be constant. . Thereby, the variation in the contact condition of the belt member 31 with respect to the defective nozzle EN is suppressed.

  After making the belt member 31 contact the defective nozzle EN, the control device CONT moves the pressing roller 33a to the −Z side by the roller driving unit 32c to release the contact state of the belt member 31. After the belt member 31 is separated from the defective nozzle EN, the contact portion of the belt member 31 is moved to the + X side by the guide rollers 32a and 32b. By this operation, the used part of the belt member 31 is retracted from the position opposed to the ejection surface Ha, and the unused part is newly arranged to face the ejection surface Ha. When the belt member 31 is brought into contact with one defective nozzle EN and then the contact state is released and the belt member 31 is brought into contact with another defective nozzle EN, an unused portion of the belt member 31 is thus used. It is effective to newly arrange the valve so as to face the injection surface Ha.

  In the above configuration, since the guide roller 32b is disposed on the −Z side with respect to the pressing roller 33a, when the belt member 31 is moved, the belt member 31 that has passed through the pressing roller 33a is directed toward the guiding roller 32b−. It moves in the Z direction. Accordingly, the ink attached to the belt member 31 moves in the −Z direction toward the guide roller 32b. For this reason, it is possible to prevent ink adhering to the belt member 31 from adhering to the ejection surface Ha.

  According to the present embodiment, a part of the belt member 31 is selectively brought into contact with the defective nozzle EN by bringing a part of the belt member 31 into contact with the defective nozzle EN in which the detection result of the detection unit 34 is defective among the plurality of nozzles NZ. A cleaning operation can be performed. Thereby, the ink consumption in the cleaning operation can be reduced. In addition, since a cleaning operation is not performed for a normal nozzle NZ that does not require a cleaning operation, it is possible to avoid a so-called induced omission that removes ink from such a normal nozzle NZ.

  In addition, according to the present embodiment, the positions of the guide roller 32a and the guide roller 32b are controlled so that the angle of the facing portion 31a is constant while the facing portion 31a of the belt member 31 is attached to the defective nozzle EN. Therefore, it is possible to suppress variation in the adhesion condition of the belt member 31 with respect to the defective nozzle EN. Thereby, stable cleaning can be performed.

  Further, according to the present embodiment, it is possible to reduce the consumption of ink required for the cleaning operation, and it is possible to avoid the induced omission and to have the cleaning device CL capable of performing stable cleaning. Therefore, it is possible to obtain a printing apparatus PRT that can reduce the running cost and can maintain the high ejection characteristics of the head H.

The technical scope of the present invention is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, an example in which the belt member 31 is conveyed to the + X side after the contact state is canceled after the pressing roller 33a brings the facing portion 31a of the belt member 31 into contact with the defective nozzle EN. However, it is not limited to this.

  For example, as shown in FIG. 12, the control device CONT may rotate the guide roller 32b in a state where the facing portion 31a is in contact with the defective nozzle EN. Due to the rotation of the guide roller 32b, the belt member 31 moves from the feed roller 30a to the take-up roller 30b. That is, the belt member 31 moves while being in contact with the defective nozzle EN. For this reason, the defective nozzle EN is wiped off by the moving belt member 31. Since the pressing roller 33 a rotates with the movement of the belt member 31, it is possible to suppress the generation of frictional force between the pressing roller 33 a and the belt member 31.

  Moreover, in the said embodiment, although it was set as the structure which used the press roller 33a about the structure of the press part 33, it is not restricted to this. As another configuration, the pressing portion 33 may be spherical.

  Moreover, although the said embodiment gave and demonstrated the aspect which makes the opposing part 31a of the belt member 31 contact only with the defective nozzle EN, it is not restricted to this. For example, the facing portion 31a of the belt member 31 may contact not only the defective nozzle EN but also other normal nozzles NZ.

  In the above-described embodiment, the configuration of the detection unit 34 is a configuration in which ink D is ejected from a plurality of nozzles NZ to detect omission and thickening. However, the configuration is not limited to this, and for example, laser light The nozzle NZ may be detected using a method such as

  Moreover, although the said embodiment gave and demonstrated the structure in which the belt member 31 was formed in one layer as an example, it is not restricted to this. For example, the belt member 31 may be formed of a plurality of layers. In this case, a layer of the belt member 31 that opposes the ejection surface Ha is formed of the material described in the above-described embodiment capable of absorbing ink, and a film that does not allow ink to permeate the back layer with respect to the ejection surface Ha. The structure formed by etc. may be sufficient. In this case, the ink absorbed by the belt member 31 can be prevented from leaking from the back side.

  Further, in addition to the cleaning operation of the above embodiment, the control device CONT has the ejection surface Ha of the head H opposed to the inclined portion of the belt member 31 between the pressing roller 33a and the guide roller 32b. An operation of discharging the ink D from the nozzle NZ to the inclined portion may be performed. In this case, the discharged ink D is absorbed by the inclined portion of the belt member 31.

  In addition, you may perform said discharge operation | movement, moving the belt member 31 with the sending roller 30a and the winding roller 30b. In this case, an unused portion of the belt member 31 can be disposed on the flight path of the discharged ink D. In the above configuration, since the guide roller 32b is disposed on the −Z side of the pressing roller 33a, it is possible to prevent the ink D received by the belt member 31 from adhering to the ejection surface Ha.

  Although this discharge operation involves consumption of ink, for example, when a number of defective nozzles EN are detected, the ejection state is shorter in time than when the opposed portion 31a of the belt member 31 is brought into contact with each nozzle. Can be restored. Therefore, when the number of detected defective nozzles EN does not exceed a preset threshold value, the control device CONT performs an operation of bringing the facing portion 31a of the belt member 31 into contact with the detected number of defective nozzles EN. Can be controlled to cause the belt member 31 to perform a flushing operation when the threshold value exceeds a preset threshold value.

  Further, the above discharge operation may be performed for each nozzle NZ, for example. As an operation example in this case, the control device CONT first causes the inclined portion between the pressing roller 33a and the guide roller 32b of the belt member 31 to face one nozzle NZ, and discharges the ink D from the nozzle NZ to the inclined portion. Let After receiving the ink D in the inclined portion, the control device CONT causes the facing portion 31a of the belt member 31 that is hung on the pressing roller 33a to face the nozzle NZ, and causes the facing portion 31a to contact the nozzle NZ. By performing this operation, the discharge operation and the contact operation can be performed compactly for each nozzle.

  In the above embodiment, as a mode of attaching a part of the belt member 31 to the ink D of the defective nozzle EN, a mode in which the facing portion 31a is brought into contact with the defective nozzle EN, more specifically, the inside of the defective nozzle EN. However, the present invention is not limited to this. For example, as an aspect in which the opposing portion 31a is brought into contact with the defective nozzle EN, the opening of the defective nozzle EN is used as the opposing portion. A mode of closing with 31a may be used.

  Further, as another aspect in which a part of the belt member 31 is attached to the ink D of the defective nozzle EN, for example, an aspect in which the facing portion 31a of the belt member 31 is brought into contact with the ink swelled from the defective nozzle EN may be used. In this case, by contacting the ink swollen from the defective nozzle EN and absorbing the ink by the belt member 31, a flow of discharging the ink can be formed inside the defective nozzle EN. With this flow, the foreign matter in the defective nozzle EN is pushed out, and the clogging of the defective nozzle EN can be eliminated.

  As another mode in which a part of the belt member 31 is adhered to the ink D of the defective nozzle EN, a mode in which a part of the belt member 31 is brought into contact with the vicinity of the defective nozzle EN on the ejection surface Ha may be used. In this case, the foreign matter can be removed by wiping with a part of the belt member 31 when the foreign matter is attached to the vicinity of the defective nozzle EN on the ejection surface Ha.

  In the above embodiment, the configuration of the serial type printing apparatus PRT that performs printing while the head H operates on the medium M has been described as an example. However, the configuration is not limited to this, and the position of the head H is determined. The present invention can be applied even to a line type printing apparatus that performs printing while fixing.

  In the above-described embodiment, the recording apparatus adopting the inkjet method as the recording method is described. However, the recording device can be changed to an arbitrary recording method such as an electrophotographic method or a thermal transfer method. Further, the recording apparatus is not limited to a printing apparatus, but may be a FAX apparatus, a copying apparatus, or a multifunction machine having a plurality of these functions. Further, as the recording apparatus, a liquid ejecting apparatus including a liquid ejecting head that ejects or ejects a small amount of liquid droplets other than ink may be employed.

  In addition, a droplet means the state of the liquid discharged from the said liquid ejecting apparatus, and shall also include what pulls a tail in granular shape, tear shape, and thread shape. The liquid here may be any material that can be ejected by the liquid ejecting apparatus. For example, it may be in a state in which the substance is in a liquid phase, such as a liquid with high or low viscosity, sol, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals (metal melts ) And a liquid as one state of a substance, as well as a material in which particles of a functional material made of a solid such as a pigment or metal particles are dissolved, dispersed or mixed in a solvent. Further, representative examples of the liquid include ink and liquid crystal as described in the above embodiment.

  Here, the ink includes general water-based inks and oil-based inks, and various liquid compositions such as gel inks and hot melt inks. As a specific example of the liquid ejecting apparatus, for example, a liquid containing a material such as an electrode material or a color material used for manufacturing a liquid crystal display, an EL (electroluminescence) display, a surface emitting display, a color filter, or the like in a dispersed or dissolved state It may be a liquid ejecting apparatus, a textile printing apparatus, or the like.

  PRT ... Printing device IJ ... Inkjet mechanism MN ... Maintenance mechanism CONT ... Control device H ... Head Ha ... Ejecting surface NZ ... Nozzle CL ... Cleaning device θ ... Angle D ... Ink EN ... Defective nozzle F1 ... Frame FL1 ... Frame FL2 ... Frame 30 ... belt drive mechanism 30a ... roller 30b ... take-off roller 30c ... roller drive part 31 ... belt member 31a ... opposed part 32 ... belt guide part 32a ... guide roller 32b ... guide roller 32c ... roller drive part 33 ... pressing part 33a ... pressure roller 34: Detection unit 80: Ink drop sensor.

Claims (7)

A liquid ejecting section having an ejection surface provided with a plurality of nozzles for ejecting liquid onto the medium;
A cleaning device for maintaining the liquid ejecting unit,
A belt member capable of holding the liquid;
A support portion that is spaced apart in the longitudinal direction of the belt member and supports the belt member so that the belt member forms a facing portion that can face the ejection surface, and one end side of the facing portion is A support part having a pressing support part to support, a lower side support part that supports the other end side of the facing part and is located below the pressing support part in the direction of gravity;
A belt drive unit for moving the belt member in the longitudinal direction;
A cleaning device that includes a detection unit that is provided at a position adjacent to the belt member in a width direction that intersects the longitudinal direction of the belt member and that can detect an ejection state of the liquid ejected from the nozzle;
A contact operation in which a portion supported by the pressing support portion of the facing portion of the belt member is brought into contact with the ejection surface, and the liquid is ejected from the nozzle in a state where the facing portion is opposed to the ejection surface. A discharge unit that performs a control operation,
Equipped with a,
Wherein the control unit, the belt the pressing support unit portion supported detected by the detecting portion of the ejection surface in a liquid jet you characterized in that selectively contacts a region including a defective nozzle member apparatus.   The liquid ejecting apparatus according to claim 1, wherein the pressing support portion is located upstream of the lower support portion in a moving direction of the belt member by the belt driving portion. The cleaning device is arranged so that the moving direction of the belt member in the facing portion is a direction along the nozzle row,
The liquid ejecting apparatus according to claim 1, wherein the control unit causes the discharge operation to be performed while moving the belt member in the longitudinal direction.   The control unit causes the liquid to be ejected from the nozzle, causes the detection unit to detect the ejection state, and then makes a portion supported by the pressing support portion of the belt member contact the ejection surface. The liquid ejecting apparatus according to any one of claims 1 to 3.   The liquid ejecting apparatus according to claim 1, wherein the control unit causes the contact operation to be performed after the discharge operation is performed.   The control unit executes the contact operation when the number of defective nozzles detected by the detection unit does not exceed a set threshold value, and the discharge operation when the number of defective nozzles exceeds a set threshold value The liquid ejecting apparatus according to any one of claims 1 to 5, wherein: A liquid ejecting portion having an ejection surface provided with a plurality of nozzles for ejecting liquid onto a medium; a belt member capable of holding the liquid; and a belt member spaced apart in the longitudinal direction of the belt member, A support portion that supports the belt member so as to form a facing portion that can face the ejection surface, and supports a pressing support portion that supports one end side of the facing portion, and the other end side of the facing portion; A support portion having a lower side support portion located below the pressing support portion in the direction of gravity, and a position adjacent to the belt member in the width direction intersecting the longitudinal direction of the belt member, and ejecting from the nozzle In a method for cleaning a liquid ejecting apparatus, comprising: a detection unit capable of detecting the ejected state of the liquid,
A detection operation for causing the liquid to be ejected from the nozzle and causing the detection unit to detect the ejection state;
A contact operation for selectively contacting a portion of the ejection portion supported by the pressing support portion of the belt member with a region including the defective nozzle detected by the detection portion of the ejection surface;
A discharge operation for ejecting the liquid from the nozzle in a state where the facing portion is opposed to the ejection surface;
A method for cleaning a liquid ejecting apparatus, comprising:

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