Printing apparatus and ink suction unit cleaning method

Abstract

To enable removal of ink from an ink suction part that suctions the ink from a discharging head to be surely executed with a simple mechanism.SOLUTION: Washing liquid is supplied to a head counter plane 71 and a dummy plane 571 of a dummy block 57a opposing the head counter plane 71 contacts the washing liquid. This enables the dummy plane 571 to scatter the washing liquid over the head counter plane 71. Further the washing liquid scattered over the head counter plane 71 is suctioned from a suction hole 72 of a suction block 7. This enables the washing liquid suctioned and then passed through the suction hole 72 to clean the suction hole 72, where removal of ink supplied to the head counter plane 71 is executed by the suction hole 72 of the suction block 7. In other words, the suction hole 72 has both functions of removing ink from a discharging head H and of removing the washing liquid from the head counter plane 71.SELECTED DRAWING: Figure 4B

Description

Technical Field

[0001] The present invention relates to a technique for cleaning an ink suction unit that sucks ink adhering to a discharge head that discharges ink.

Background Art

[0002] Conventionally, a discharge head that discharges ink by an inkjet method has been used in a printing apparatus. In such a printing apparatus, it is known that discharge defects such as the inability to appropriately discharge ink from a nozzle occur due to the solidification of the ink adhering to the discharge head. Therefore, in Patent Documents 1 to 3, cleaning for removing ink from the discharge head is appropriately performed using a cap, a wiper, or the like.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in order to remove ink from the discharge head as described above, an ink suction unit that sucks ink from a suction hole facing the discharge head can be used. However, when the ink suction unit repeatedly sucks ink, the ink suction unit itself may be contaminated with ink. In this regard, it is effective to separately provide a mechanism for removing ink from the ink suction unit. On the other hand, the addition of such a mechanism can be a factor in complicating the configuration of the printing apparatus and increasing costs.

[0005] The present invention has been made in view of the above problems, and an object thereof is to enable the removal of ink from an ink suction unit that sucks ink from a discharge head with a simple mechanism.

Means for Solving the Problems

[0006] The printing apparatus according to the present invention includes a discharge head that has an ink discharge surface where nozzles are open and discharges ink from the nozzles, an ink suction unit that has a head facing surface where suction holes are open and sucks ink from the suction holes, a negative pressure applying unit that applies a negative pressure to the suction holes of the ink suction unit, a cleaning liquid supply unit that supplies a cleaning liquid to the head facing surface, a cleaning auxiliary member that has a cleaning auxiliary surface, a head cleaning region where the head facing surface faces the ink discharge surface, and a drive unit that moves the ink suction unit between the head cleaning region and a self-cleaning region where the head facing surface faces the cleaning auxiliary surface, and a control unit that controls the negative pressure applying unit, the cleaning liquid supply unit, and the drive unit. The control unit includes a negative pressure control unit that controls the negative pressure applying unit, a drive control unit that controls the drive unit, and a supply control unit that controls the cleaning liquid supply unit. During head cleaning, the drive control unit controls the drive unit to move the ink suction unit to the head cleaning region, and further moves the ink suction unit while the head facing surface of the ink suction unit faces the ink discharge surface of the discharge head within the head cleaning region. The negative pressure control unit controls the negative pressure applying unit to activate it, and applies a negative pressure to the suction holes of the ink suction unit Cause to occur By doing so, the ink adhering to the ink discharge surface is sucked from the suction holes. During self-cleaning, the drive control unit controls the drive unit to move the ink suction unit to the self-cleaning region, and within the self-cleaning region, the head facing surface of the ink suction unit is made to face the cleaning auxiliary surface. The supply control unit controls the cleaning liquid supply unit to supply the cleaning liquid from the cleaning liquid supply unit to the head facing surface of the ink suction unit within the self-cleaning region. The negative pressure control unit controls the negative pressure applying unit to activate it, and applies a negative pressure to the suction holes of the ink suction unit Cause to occur By doing so, it is configured to suck the cleaning liquid from the suction holes while bringing the cleaning liquid supplied to the head facing surface into contact with the cleaning auxiliary surface.

[0007] The ink suction unit cleaning method according to the present invention includes a step of supplying a cleaning liquid to a head facing surface of an ink suction unit that sucks ink adhered to an ink ejection surface of a discharge head that ejects ink from a nozzle opening to the ink ejection surface, a step of bringing a cleaning auxiliary surface of a cleaning auxiliary member facing the head facing surface into contact with the cleaning liquid supplied to the head facing surface, and a step of sucking the cleaning liquid on the head facing surface from a suction hole.

[0008] In the present invention (printing apparatus, ink suction unit cleaning method) configured as described above, the ink suction unit has a head facing surface where a suction hole opens, and removes ink from the discharge head by sucking the ink adhered to the ink ejection surface of the discharge head from the suction hole. Therefore, the head facing surface and the suction hole of the ink suction unit are contaminated by the ink. Thus, the cleaning of the ink suction unit is performed as follows.

[0009] That is, the cleaning liquid is supplied to the head facing surface, and the cleaning auxiliary surface of the cleaning auxiliary member facing the head facing surface comes into contact with this cleaning liquid. As a result, the cleaning liquid is spread over the head facing surface by the cleaning auxiliary surface. In this way, the cleaning liquid can be spread over a wide area of the head facing surface to clean the head facing surface. Further, the cleaning liquid spread over the head facing surface is sucked from the suction hole of the ink suction unit. Therefore, the suction hole can be cleaned by the cleaning liquid passing through the suction hole during suction. In this way, it is possible to surely clean both the head facing surface and the suction hole of the ink suction unit. At this time, the removal of the ink supplied to the head facing surface is performed by the suction hole of the ink suction unit. That is, the suction hole has both functions of removing ink from the discharge head and removing the cleaning liquid from the head facing surface. Therefore, there is no need to separately provide a mechanism for removing the cleaning liquid, and the ink suction unit can be cleaned with a simple mechanism. In this way, it is possible to surely perform the removal of ink from the ink suction unit that sucks ink from the discharge head with a simple mechanism.

[0010] Further, a supply hole may be formed in the head facing surface, and the cleaning liquid supply unit may be configured to supply the cleaning liquid from the supply hole to the head facing surface of the printing apparatus. In such a configuration, the cleaning liquid is supplied from the supply hole formed in the head facing surface of the ink suction unit. In other words, the ink suction unit supplies the cleaning liquid to the head facing surface by itself. Thus, the simplification of the mechanism can be more surely achieved.

[0011] Further, the discharge head and the cleaning auxiliary member are arranged in a predetermined horizontal direction, and the height of the head facing surface of the ink suction unit located in the head cleaning area is the same as the height of the head facing surface of the ink suction unit located in the self-cleaning area. The drive control unit may be configured to control the drive unit to move the ink suction unit to the head cleaning area to perform head cleaning on the ink suction unit, and then control the drive unit to move the suction unit from the head cleaning area to the self-cleaning area to perform self-cleaning. In such a configuration, a smooth transition from head cleaning to self-cleaning can be achieved by a simple operation of moving the ink suction unit in the horizontal direction.

[0012] Further, in the horizontal direction, a positioning member arranged on the opposite side of the cleaning auxiliary member with respect to the discharge head is further provided. The positioning member has a contact surface provided with respect to the height of the head facing surface of the ink suction unit located in the head cleaning area. The drive control unit may be configured to control the drive unit to move the ink suction unit to a position where its head facing surface abuts against the contact surface of the positioning member, and then move the ink suction unit in the horizontal direction to move the ink suction unit to the head cleaning area. In such a configuration, the head facing surface can be positioned at the height when performing head cleaning and self-cleaning by bringing the head facing surface of the ink suction unit into contact with the contact surface of the positioning member. Therefore, by moving the ink suction unit in the horizontal direction after bringing the head facing surface into contact with the contact surface, head cleaning and self-cleaning can be smoothly started.

[0013] Further, the control unit further includes a supply control unit that controls the cleaning liquid supply unit. The supply control unit controls the cleaning liquid supply unit so that the cleaning liquid is supplied from the cleaning liquid supply unit for a first supply time. After the negative pressure control unit performs the first self-cleaning one or more times to control the negative pressure applying unit so that the cleaning liquid is sucked from the suction hole for a first suction time, the supply control unit controls the cleaning liquid supply unit so that the cleaning liquid is supplied from the cleaning liquid supply unit for a second supply time that is longer than the first supply time. The printing apparatus may be configured such that the negative pressure control unit performs a second self-cleaning to control the negative pressure applying unit so that the cleaning liquid is sucked from the suction hole for a second suction time that is longer than the first suction time. In such a configuration, the self-cleaning is performed at least twice (the first and second self-cleanings). At this time, the time (second supply time) during which the cleaning liquid is supplied in the later second self-cleaning is longer than the time (first supply time) during which the cleaning liquid is supplied in the previous first self-cleaning, and the time (second suction time) during which the cleaning liquid is sucked in the later second self-cleaning is longer than the time (first suction time) during which the cleaning liquid is sucked in the previous first self-cleaning. Thus, by performing the second self-cleaning in which the supply time and the suction time of the cleaning liquid are provided relatively long, the cleaning of the ink suction unit is completed, and the removal of the ink from the ink suction unit can be performed more reliably.

Effect of the Invention

[0014] As described above, according to the present invention, it is possible to reliably remove the ink from the ink suction unit that sucks the ink from the discharge head with a simple mechanism.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 4C

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0016] FIG. 1 is a front view schematically showing an example of a printing system including a printing apparatus according to the present invention. In FIG. 1 and the figures shown below, the horizontal direction X and the vertical direction Z are appropriately shown. As shown in FIG. 1, the printing system 1 includes a printing apparatus 3 and a drying apparatus 9 arranged in the horizontal direction X. This printing system 1 conveys a long strip-shaped printing medium M from a unwind roll 11 to a windup roll 12 in a roll-to-roll manner. Note that the material of the printing medium M is a film such as OPP (oriented polypropylene) or PET (polyethylene terephthalate). However, the material of the printing medium M is not limited to a film, and may be paper or the like. Such a printing medium M has flexibility. Also, hereinafter, of the two sides of the printing medium M, the surface on which an image is printed is appropriately referred to as the front surface M1, and the surface on the opposite side of the front surface M1 is referred to as the back surface M2. terephthalate), etc. However, the material of the printing medium M is not limited to a film, and may be paper or the like. Such a printing medium M has flexibility. Also, hereinafter, of the two sides of the printing medium M, the surface on which an image is printed is appropriately referred to as the front surface M1, and the surface on the opposite side of the front surface M1 is referred to as the back surface M2.

[0017] The printing device 3 prints an image on the surface M1 of the printing medium M conveyed from the unwinding roll 11 to the winding roll 12 by ejecting aqueous ink onto the surface M1 of the printing medium M by an inkjet method. The detailed configuration of such a printing device 3 will be described later. The printing medium M on which the image is thus printed is conveyed in the horizontal direction X from the printing device 3 toward the drying device 9.

[0018] The drying device 9 includes a drying furnace 90 and dries the printing medium M unloaded from the printing device 3 as it is conveyed from the unwinding roll 11 to the winding roll 12. Inside the drying furnace 90, there are provided two upper-stage air supply units 91u arranged in the horizontal direction X, two middle-stage air supply units 91m arranged in the horizontal direction X below these upper-stage air supply units 91u, and two lower-stage air supply units 91l arranged in the horizontal direction X below these middle-stage air supply units 91m.

[0019] The printing medium M unloaded from the unloading port 312 of the printing device 3 is folded back toward the two middle-stage air supply units 91m by a pair of rollers 92 after passing through the two upper-stage air supply units 91u in the horizontal direction X. Subsequently, the printing medium M is folded back toward the two lower-stage air supply units 91l by a pair of air turn bars 93 after passing through the two middle-stage air supply units 91m in the horizontal direction X. Further, the printing medium M is unloaded to the outside of the drying device 9 after passing through the two lower-stage air supply units 91l in the horizontal direction X.

[0020] The upper-stage air supply unit 91u has two air supply chambers 94 arranged so as to sandwich the printing medium M passing in the horizontal direction X from the vertical direction Z. Each air supply chamber 94 has a plurality of nozzles 95 arranged in the horizontal direction X, and hot air (gas at 60 degrees or more) is jetted from each nozzle 95 onto the printing medium M. Thus, the printing medium M is dried by the hot air jetted from the nozzles 95 of these air supply chambers 94 while passing between the two air supply chambers 94 provided above and below. Also, each of the middle-stage air supply unit 91m and the lower-stage air supply unit 91l similarly has two air supply chambers 94 that sandwich the printing medium M from the vertical direction Z.

[0021] Incidentally, the specific configuration of the upper air supply unit 91u is not limited to this example. For example, instead of the lower air supply chamber 94 among the upper and lower air supply chambers 94 of the upper air supply unit 91u, a plurality of rollers arranged in the horizontal direction X may be provided. In such a configuration, while the back surface M2 of the printing medium M is supported from below by the plurality of rollers, warm air can be jetted from the upper air supply chamber 94 onto the front surface M1 of the printing medium M.

[0022] FIG. 2 is a front view schematically showing the printing apparatus included in the printing system of FIG. 1. In FIG. 2, one side X1 and the other side X2 in the horizontal direction X are appropriately shown. Here, one side X1 is the side facing from the printing apparatus 3 to the drying apparatus 9, and the other side X2 is the opposite side of one side X1. The printing apparatus 3 includes a housing 31, a color printing unit 32 disposed within the housing 31, a white printing unit 33 disposed above the color printing unit 32 within the housing 31, and a conveyance unit 4 that conveys the printing medium M by a plurality of rollers disposed within the housing 31.

[0023] The color printing unit 32 has a plurality (six) of head units 321 arranged in the traveling direction of the printing medium M (the direction from the other side X2 to the one side X1) above the printing medium M conveyed by the conveyance unit 4. The plurality of head units 321 each have nozzles facing the front surface M1 of the printing medium M passing therebelow from above, and eject color inks of different colors from the nozzles by an inkjet method. Here, the color ink means an ink other than white, and includes inks such as cyan, magenta, yellow, and black. Thus, the plurality of head units 321 of the color printing unit 32 print a color image on the front surface M1 of the printing medium M by ejecting color ink from above onto the front surface M1 of the printing medium M passing therebelow.

[0024] Further, the white printing unit 33 has a single head unit 331 disposed above the printing medium M conveyed by the conveying unit 4. The head unit 331 has nozzles facing the surface M1 of the printing medium M passing therebelow from above, and ejects white ink from the nozzles in an inkjet manner. Thus, the head unit 331 of the white printing unit 33 prints a white image on the surface M1 of the printing medium M by ejecting white ink from above onto the surface M1 of the printing medium M passing therebelow.

[0025] On the side wall of the other side X2 of the housing 31, an inlet 311 is open, while on the side wall of one side X1 of the housing 31, an outlet 312 is open. Then, the conveying unit 4 conveys the printing medium M from the inlet 311 to the outlet 312 while passing through the color printing unit 32 and the white printing unit 33 described above.

[0026] This conveying unit 4 has a loading unit 41 provided below the color printing unit 32, a rising conveying unit 42 provided on one side X1 of the color printing unit 32, an upper conveying unit 43 provided above the color printing unit 32, and a descending conveying unit 44 provided on the other side X2 of the color printing unit 32. The loading unit 41 conveys the printing medium M loaded from the inlet 311 to one side X1 by rollers 411, the rising conveying unit 42 conveys the printing medium M conveyed by the loading unit 41 upward by rollers 421, the upper conveying unit 43 conveys the printing medium M conveyed by the rising conveying unit 42 to the other side X2 by rollers 431, and the descending conveying unit 44 conveys the printing medium M conveyed by the upper conveying unit 43 downward by rollers 441.

[0027] Further, the conveying unit 4 has a color conveying unit 45 that supports the printing medium M facing the color printing unit 32 from below, and the printing medium M that has passed through the descending conveying unit 44 enters the color conveying unit 45. This color conveying unit 45 has a plurality of rollers 451 arranged from the other side X2 to the one side X1, and each roller 451 contacts the back surface M2 of the printing medium M from below. Thus, the front surface M1 of the printing medium M supported by the color conveying unit 45 faces upward, and each head unit 321 of the color printing unit 32 discharges color ink while facing this front surface M1 from above.

[0028] Also, the conveying unit 4 has rollers 461, 462, and 463 arranged between the color conveying unit 45 and the descending conveying unit 44 in the advancing direction of the printing medium M. The roller 461 is a driving roller that drives the printing medium M. The rollers 462 and 463 are driven rollers that rotate following the printing medium M.

[0029] Furthermore, the conveying unit 4 has a reversing conveying unit 47 that reverses the printing medium M conveyed from the color conveying unit 45 to the one side X1 up and down twice. This reversing conveying unit 47 has a plurality of rollers 471 to 477 including a driving roller 471, and while these rollers 471 to 477 contact the back surface M2 of the printing medium M, the printing medium M is reversed up and down twice. That is, the reversing conveying unit 47 conveys the printing medium M conveyed from the color conveying unit 45 downward by the rollers 471 and 472, and further changes the advancing direction of the printing medium M to the other side X2 by the roller 472 and conveys it, thereby reversing the front surface M1 and the back surface M2 of the printing medium M. Subsequently, the reversing conveying unit 47 conveys the printing medium M from the one side X1 to the other side X2 by a plurality of rollers 473, and then conveys the printing medium M upward by the rollers 474 to 476. Furthermore, the reversing conveying unit 47 reverses the front surface M1 and the back surface M2 of the printing medium M again by changing the advancing direction of the printing medium M to the one side X1 by the roller 476, and conveys the printing medium M from the other side X2 to the one side X1 by the roller 477.

[0030] Further, the conveying unit 4 has a white conveying unit 48 that supports the printing medium M facing the white printing unit 33 from below, and the printing medium M that has been vertically inverted twice by the inversion conveying unit 47 enters the white conveying unit 48. This white conveying unit 48 has a roller 481 that contacts the back surface M2 of the printing medium M from below. In this way, the front surface M1 of the printing medium M supported by the white conveying unit 48 faces upward, and the head unit 331 of the white printing unit 33 discharges white ink while facing this front surface M1 from above.

[0031] Also, the conveying unit 4 has a discharge unit 49 provided above the upper conveying unit 43. The discharge unit 49 has a plurality of rollers 491 arranged from the other side X2 to the one side X1 in the horizontal direction X. This discharge unit 49 conveys the printing medium M conveyed by the white conveying unit 48 to the one side X1 by the plurality of rollers 491, and discharges it from the discharge port 312 of the housing 31 to the drying device 9.

[0032] As described above, the color printing unit 32 and the white printing unit 33 of the printing device 3 have head units 321 and 331. Subsequently, these head units 321 and 331 will be described. Note that these basic configurations are common to each of the head units 321 and 331. Therefore, hereinafter, one head unit 321 will be described, and the description of the other head units 321 and 331 will be omitted. Also, the discharge head H of the head unit 321 is slightly inclined according to the posture of the printing medium M. However, since the inclination of the discharge head H is slight, the inclination is not shown in the figures shown below.

[0033] FIG. 3A is a bottom view schematically showing the bottom surface of the head unit, and FIG. 3B is a side view schematically showing the side surface of the head unit. In FIGS. 3A and 3B, in addition to the horizontal direction X and the vertical direction Z, a horizontal direction Y orthogonal to the horizontal direction X is shown. As shown in FIG. 3A, in the head unit 321, a plurality of discharge heads H that discharge the same color of ink are arranged in a row in the horizontal direction Y. Note that the arrangement mode of the discharge heads H is not limited to the example of FIG. 3A, and a plurality of discharge heads H may be arranged in a staggered manner.

[0034] This ejection head H has a housing Ha, and the bottom surface of the housing Ha has an ink ejection plane Hb1 and protruding planes Hb2 provided on both sides of the ink ejection plane Hb1 in the horizontal direction X. The ink ejection plane Hb1 and the protruding planes Hb2 are parallel to each other and face the surface M1 of the printing medium M. As shown in FIG. 3B, the two protruding planes Hb2 arranged in the horizontal direction X are located at the same height (in other words, flush). On the other hand, the ink ejection plane Hb1 is located above the two protruding planes Hb2. That is, the two protruding planes Hb2 protrude downward more than the ink ejection plane Hb1 between the two protruding planes Hb2. These protruding planes Hb2 are made of, for example, glass fiber.

[0035] In the ink ejection plane Hb1, a plurality of nozzles Hc are arranged and open in the horizontal direction Y. In the example of FIG. 3A, the plurality of nozzles Hc are arranged in a single row, but the arrangement pattern of these nozzles Hc is not limited to this example. For example, these nozzles Hc may be arranged in a staggered pattern in the horizontal direction Y. Each nozzle Hc thus provided in the ink ejection plane Hb1 ejects ink toward the surface M1 of the printing medium M. Note that the ejection of ink can be executed by various inkjet technologies such as the piezo method or the thermal method.

[0036] Furthermore, the printing apparatus 3 includes a maintenance unit 51 (FIGS. 4A, 4C, and 5) that performs maintenance on each ejection head H. Subsequently, the maintenance unit 51 will be described. The maintenance unit 51 is arranged for each of the plurality of head units 321, 331, and the configuration and operation of the maintenance unit 51 provided in each head unit 321, 331 are common. Therefore, here, one maintenance unit 51 will be described. Also, the maintenance unit 51 tilts slightly according to the posture of the head unit 321 or the head unit 331 to be cleaned. However, since the tilt of the maintenance unit 51 is slight, the tilt is not shown in the figures shown below.

[0037] FIG. 4A is a diagram schematically showing an example of head suction cleaning and self-cleaning performed by the maintenance unit, FIG. 4B is a diagram schematically showing details of the operations performed in FIG. 4A, FIG. 4C is a diagram schematically showing an example of head wiping cleaning performed by the maintenance unit, FIG. 5 is a diagram schematically showing a partial configuration of the maintenance unit, and FIG. 6 is a block diagram showing the electrical configuration provided in the printing apparatus for controlling the maintenance unit.

[0038] As shown in FIGS. 4A and 4C, the printing apparatus 3 includes a maintenance unit 51 and a linear motion mechanism 55 that drives the maintenance unit 51 in the horizontal direction Y. The linear motion mechanism 55 is constituted by, for example, a ball screw or a linear motor, and moves the maintenance unit 51 between an opposing position La and a retracted position Lb provided at an interval from the opposing position La in the horizontal direction Y. The maintenance unit 51 located at the opposing position La faces a plurality of ejection heads H, while the maintenance unit 51 located at the retracted position Lb does not face the plurality of ejection heads H. Further, in order to avoid interference with the maintenance unit 51, the plurality of ejection heads H can move up and down integrally. In particular, the plurality of ejection heads H are located at any one of a printing height Hl, a cap height Hm higher than the printing height Hl, and a retracted height Hh higher than the cap height Hm. Note that the heights Hl, Hm, and Hh are represented by the height of the lower end surface of the ejection head H, that is, the protruding plane Hb2.

[0039] Also, as shown in FIGS. 4A and 4C, dummy blocks 57a and 57b are provided on both sides of the head unit 321 in the horizontal direction Y. The dummy blocks 57a and 57b have the same configuration and are made of, for example, polyacetal. These dummy blocks 57a and 57b are attached to the head unit 321 and move up and down integrally with the head unit 321. Further, the dummy blocks 57a and 57b have a dummy plane 571 (FIG. 4B) on their bottom surfaces. This dummy plane 571 is a plane parallel to the protruding plane Hb2 of the discharge head H, and the height of the dummy plane 571 is the same as the height of the protruding plane Hb2 of the discharge head H. That is, the dummy plane 571 of the dummy blocks 57a and 57b and the protruding plane Hb2 of the discharge head H are provided flush.

[0040] The maintenance unit 51 includes a cap 53, a wiping unit 6, and a suction block 7. The cap 53 performs capping that covers the discharge head H from below. As shown in FIG. 5, the wiping unit 6 has an unwinding roller 61 and a winding roller 62 arranged at intervals in the horizontal direction Y, and conveys the sheet S in a roll-to-roll manner from the unwinding roller 61 to the winding roller 62. Further, the wiping unit 6 has a wiping roller 63 that winds the sheet S from below between the unwinding roller 61 and the winding roller 62. This wiping unit 6 wipes the ink adhering to the ink discharge plane Hb1 with the sheet S by conveying the sheet S while sandwiching the sheet S between the wiping roller 63 and the ink discharge plane Hb1 of the discharge head H (head wiping cleaning). A long strip-shaped cloth is used as the sheet S. However, the material of the sheet S is not limited to cloth and may be, for example, paper.

[0041] In addition, the maintenance unit 51 has a lifting mechanism E6 for lifting and lowering the wiping unit 6 with respect to the housing 511 of the maintenance unit 51. Specifically, when the wiping unit 6 performs head wiping and cleaning, the lifting mechanism E6 raises the wiping unit 6, while when the wiping unit 6 does not perform wiping and cleaning, the lifting mechanism E6 lowers the wiping unit 6. As such a lifting mechanism E6, an actuator or the like can be used.

[0042] The suction block 7 is disposed between the cap 53 and the wiping unit 6 in the horizontal direction Y. This suction block 7 has a head-facing plane 71 on its upper surface. The head-facing plane 71 is a plane parallel to the dummy planes 571 of the dummy blocks 57a and 57b and the protruding plane Hb2 of the discharge head H. Further, the suction block 7 has a suction hole 72 and a supply hole 73 that open to the head-facing plane 71. The suction hole 72 sucks ink and cleaning liquid from the head-facing plane 71 by the negative pressure applied by the cleaning unit 8 (FIG. 6), and the supply hole 73 discharges the cleaning liquid supplied from the cleaning unit 8 onto the head-facing plane 71.

[0043] In addition, the maintenance unit 51 has a lifting mechanism E7 for lifting and lowering the suction block 7 with respect to the housing 511 of the maintenance unit 51. Specifically, when the suction block 7 performs head suction cleaning and self-cleaning, which will be described later, the lifting mechanism E7 raises the suction block 7, while when the suction block 7 does not perform these cleanings, the lifting mechanism E7 lowers the suction block 7. As such a lifting mechanism E7, an actuator or the like can be used.

[0044] As shown in FIG. 6, the printing apparatus 3 includes a control unit 391 composed of a processor such as a CPU (Central Processing Unit). FIG. 6 also illustrates each functional unit of the control unit 391. The control unit 391 includes a drive control unit 391a, a negative pressure control unit 391b, and a supply control unit 391c. The drive control unit 391a controls the operation of the linear motion mechanism 55 to move the maintenance unit 51 between the facing position La and the retracted position Lb provided at an interval from the facing position La in the horizontal direction Y. Further, the drive control unit 391a controls the operation of the lifting mechanism E6 to raise and lower the wiping unit 6 with respect to the housing 511 of the maintenance unit 51. Furthermore, the drive control unit 391a controls the operation of the lifting mechanism E7 to raise and lower the suction block 7 with respect to the housing 511 of the maintenance unit 51. The negative pressure control unit 391b controls the opening and closing operations of the on-off solenoid valves 842 and 846 that constitute the negative pressure applying unit 84 to be described later, thereby executing the application or stop of the negative pressure to the suction holes 72 formed in the suction block 7. The supply control unit 391c controls the supply operation of the liquid supply pump 822 and the opening and closing operation of the on-off solenoid valve 823 to be described later, thereby executing the supply or stop of the cleaning liquid to the supply holes 73 formed in the suction block 7. Then, by the drive control unit 391a, the negative pressure control unit 391b, and the supply control unit 391c controlling the operations of the linear motion mechanism 55, the lifting mechanism E6, the lifting mechanism E7, and the on-off solenoid valves 842, 846, the liquid supply pump 822, and the on-off solenoid valve 823 included in the cleaning unit 8, respectively, the operations shown in FIGS. 4A to 4C are executed.

[0045] In step S101 of FIG. 4A, the maintenance unit 51 is located at the facing position La, and the head unit 321 is located at the cap height Hm. Therefore, the cap 53 of the maintenance unit 51 abuts on the head unit 321 and covers the plurality of ejection heads H from below (capping). On the other hand, the wiping unit 6 and the suction block 7 project from the head unit 321 to the opposite side of the retracted position Lb in the horizontal direction Y.

[0046] In step S102, the head unit 321 rises from the cap height Hm to the retracted height Hh. As a result, the plurality of ejection heads H and the cap 53 are separated, and capping is released. On the other hand, the head facing plane 71 of the suction block 7 is located at a standby position H7 (FIG. 4B) lower than the retracted height Hh. That is, the head facing plane 71 of the suction block 7 is located below the dummy plane 571 of the dummy block 57b.

[0047] In step S103, the drive control unit 391a controls the linear motion mechanism 55 to adjust the position of the suction block 7 in the horizontal direction Y so that the head facing plane 71 of the suction block 7 and the dummy plane 571 of the dummy block 57b are aligned in the horizontal direction Y. Then, the drive control unit 391a controls the lifting mechanism E7 to raise the suction block 7. As a result, the head facing plane 71 of the suction block 7 rises from the standby position H7 to the retracted height Hh and abuts against the dummy plane 571 of the dummy block 57b.

[0048] In step S104, the drive control unit 391a controls the linear motion mechanism 55 to start moving in the horizontal direction Y from the facing position La to the retracted position Lb of the maintenance unit 51. As a result, the suction block 7 moves toward the facing position La within the head cleaning region Rh that faces the ink ejection plane Hb1 of the ejection head H. While the suction block 7 is moving within the head cleaning region Rh, the head facing plane 71 of the suction block 7 faces the ink ejection plane Hb1 and the protruding plane Hb2 from below and is positioned at the same retracted height Hh as the protruding plane Hb2 of the ejection head H. Therefore, while both ends of the head facing plane 71 are in contact with the protruding plane Hb2, the suction holes 72 and the supply holes 73 provided at the center of the head facing plane 71 (the range between the two ends) face the ink ejection plane Hb1, and the suction block 7 moves. Further, while the suction block 7 is moving within the head cleaning region Rh, the negative pressure control unit 391b controls to activate the negative pressure applying unit 84 described later, and controls the on-off solenoid valve 842 and the on-off solenoid valve 846 constituting the negative pressure applying unit 84 to open. As a result, a negative pressure is applied to the suction holes 72 formed in the suction block 7, and the suction holes 72 execute suction. Thereby, the ink adhering to the ink ejection plane Hb1 of the ejection head H is sucked from the suction holes 72, and the ink is removed from the ejection head H (head suction cleaning).

[0049] In step S105, the drive control unit 391a controls the linear motion mechanism 55 so that the suction block 7 that has passed through the head cleaning region Rh stops in the self-cleaning region Rs that faces the dummy plane 571 of the dummy block 57a. As a result, the head facing plane 71 of the suction block 7 contacts the dummy plane 571 of the dummy block 57a from below. Then, the negative pressure control unit 391b controls to activate the negative pressure applying unit 84 described later, and the supply control unit 391c controls the cleaning liquid supply unit 82 described later to supply the cleaning liquid to the head facing plane 71. Thereby, the suction block 7 performs self-cleaning described in detail later to remove the ink adhering to the head facing plane 71 and the suction holes 72.

[0050] When the self-cleaning in step S105 is completed, as shown in step S106 of FIG. 4C, the drive control unit 391a controls the linear motion mechanism 55 to move the maintenance unit 51 to the retracted position Lb. Further, the drive control unit 391a controls the operation of the lifting mechanism E7 to lower the suction block 7 from the retracted height Hh to the standby position H7, and controls the operation of the lifting mechanism E6 to raise the wiping unit 6.

[0051] In step S107, the drive control unit 391a controls the linear motion mechanism 55 to start moving the maintenance unit 51 from the retracted position Lb toward the opposing position La. Then, when the sheet S contacts the ink ejection plane Hb1 of the ejection head H, the wiping unit 6 starts the roll-to-roll conveyance of the sheet S while continuing to move in the horizontal direction Y. Thereby, the ink adhering to the ink ejection plane Hb is wiped off by the sheet S (head wiping cleaning).

[0052] When the maintenance unit 51 arrives at the opposing position La (step S108), the cap 53 of the maintenance unit 51 faces the plurality of ejection heads H from below. On the other hand, the wiping unit 6 and the suction block 7 stop at positions protruding from the plurality of ejection heads H in the horizontal direction Y. Subsequently, the plurality of ejection heads H descend from the retracted height Hh to the cap height Hm (step S109). Thereby, each ejection head H is covered from below by the cap 53 (capping).

[0053] Subsequently, the details of the configuration and operation regarding the head suction cleaning and self-cleaning performed by the suction block 7 will be described. FIG. 7 is a perspective view schematically showing the external configuration of the suction block, and FIG. 8 is a diagram schematically showing the configuration of the cleaning unit 8 that supplies the negative pressure and cleaning liquid necessary for the cleaning operation by the suction block.

[0054] As shown in FIG. 7, in the head-facing plane 71 of the suction block 7, a plurality of suction holes 72 are arranged in a row in the horizontal direction X, and a plurality of supply holes 73 are arranged in a row in the horizontal direction X. However, the arrangement pattern of the suction holes 72 and the supply holes 73 is not limited to this example, and the suction holes 72 and the supply holes 73 may be arranged alternately. Alternatively, the arrangement direction of the suction holes 72 and the supply holes 73 may be the horizontal direction Y instead of the horizontal direction X.

[0055] Then, the cleaning unit 8 can supply a negative pressure to the suction holes 72 and supply a cleaning liquid to the supply holes 73. This cleaning unit 8 includes a cleaning liquid supply unit 82. This cleaning liquid supply unit 82 has a cleaning liquid tank 81, and the cleaning liquid tank 81 stores the cleaning liquid. This cleaning liquid is composed of, for example, components other than the coloring components (pigments and dyes) among the components of the ink. Further, the cleaning liquid supply unit 82 has a pipe 821 connecting the cleaning liquid tank 81 and the supply holes 73, a liquid feed pump 822 provided in the pipe 821, and an on-off solenoid valve 823 attached to the pipe 821 between the liquid feed pump 822 and the supply holes 73. The supply control unit 391c controls the liquid feeding operation of the liquid feed pump 822 and the opening and closing operation of the on-off solenoid valve 823. Then, with the on-off solenoid valve 823 opened under the control of the supply control unit 391c, the liquid feed pump 822 supplies the cleaning liquid from the cleaning liquid tank 81 to the supply holes 73 through the pipe 821. Also, the supply of the cleaning liquid to the supply holes 73 can be stopped by stopping the liquid feed pump 822 or closing the on-off solenoid valve 823.

[0056] Further, the cleaning unit 8 includes a negative pressure applying unit 84. The negative pressure applying unit 84 includes a suction liquid trap tank 83, a pipe 841 connecting the suction liquid trap tank 83 and the suction hole 72, an on-off solenoid valve 842 attached to the pipe 841, a pipe 843 connecting the suction liquid trap tank 83 and the exhaust port 85, an ejector 844 attached to the pipe 843, a pipe 845 connecting the ejector 844 and a positive pressure source, and an on-off solenoid valve 846 attached to the pipe 845. The negative pressure control unit 391b controls the opening and closing operations of the on-off solenoid valve 842 and the on-off solenoid valve 846. When the on-off solenoid valve 846 opens and the positive pressure from the positive pressure source is supplied to the ejector 844, the ejector 844 generates a negative pressure in response to the supply of the positive pressure and discharges the gas (air) in the suction liquid trap tank 83 to the exhaust port 85. As a result, a negative pressure is generated in the suction liquid trap tank 83. Therefore, when the on-off solenoid valve 842 is open, the negative pressure in the suction liquid trap tank 83 is supplied to the suction hole 72 through the pipe 841. Then, the liquid (ink / cleaning liquid) sucked by the suction hole 72 due to the negative pressure is trapped in the suction liquid trap tank 83 through the pipe 841. On the other hand, by closing at least one of the on-off solenoid valve 842 and the on-off solenoid valve 846, the supply of the negative pressure to the suction hole 72 can be stopped. In this way, the negative pressure control unit 391b activates the negative pressure applying unit 84 and controls the on-off solenoid valve 842 and the on-off solenoid valve 846 to open, thereby applying a negative pressure to the suction hole 72 on the head facing plane 71. On the other hand, the negative pressure control unit 391b controls to close at least one of the on-off solenoid valve 842 and the on-off solenoid valve 846 that constitute the negative pressure applying unit 84, thereby deactivating the negative pressure applying unit 84 and stopping the supply of the negative pressure to the suction hole 72.

[0057] Then, the supply control unit 391c controls the liquid feed pump 822 and the on-off solenoid valve 823, and the negative pressure control unit 391b controls the on-off solenoid valve 842 and the on-off solenoid valve 846 to supply the cleaning liquid to the supply hole 73 and supply the negative pressure to the suction hole 72. For example, during the execution of the head suction cleaning in step S104 described above, while stopping the supply of the cleaning liquid to the supply hole 73, a negative pressure is applied to the suction hole 72 to suck the ink adhering to the ink ejection plane Hb1 from the suction hole 72 and collect it in the suction liquid trap tank 83. Further, in the self-cleaning in step S105, the operation shown in FIG. 9 below is executed.

[0058] FIG. 9 is a diagram schematically showing an example of the self-cleaning executed by the suction block. As described above, in response to the start of self-cleaning, the dummy block 57 is positioned in the self-cleaning region Rs (step S201). As a result, the head facing plane 71 of the suction block 7 comes into contact with the dummy plane 571 of the dummy block 57a from below and is covered by the dummy plane 571. Also, in this step S201, the supply of the cleaning liquid to the supply hole 73 and the supply of the negative pressure to the suction hole 72 are stopped.

[0059] In step S202, the supply of the cleaning liquid to the supply hole 73 is started. As a result, the cleaning liquid discharged from the supply hole 73 is supplied to the head facing plane 71. On the other hand, the dummy plane 571 of the dummy block 57a is in contact with the head facing plane 71, and the cleaning liquid supplied to the head facing plane 71 comes into contact with the dummy plane 571. Therefore, as shown by the arrow in step S203, the cleaning liquid supplied to the head facing plane 71 is spread along the head facing plane 71 by the dummy plane 571.

[0060] Then, when the supply of the cleaning liquid to the supply hole 73 is stopped, the application of negative pressure to the suction hole 72 is started (step S204). As a result, the cleaning liquid supplied to the head facing plane 71 is sucked by the suction hole 72 and recovered in the suction liquid trap tank 83. In this way, the cleaning liquid is removed from the head facing plane 71. Incidentally, the application of negative pressure may be started before the supply of the cleaning liquid is stopped. According to such an operation, there will be a period during which the cleaning liquid is supplied to the head facing plane 71 and the cleaning liquid is sucked from the head facing plane 71. In this case, after the supply of the cleaning liquid is stopped, the supply of negative pressure may be continued for a predetermined time and then the supply of negative pressure may be stopped.

[0061] In the embodiment described above, the suction block 7 (ink suction unit) has a head facing plane 71 (head facing surface) where the suction hole 72 opens, and removes ink from the discharge head H by sucking the ink adhering to the ink discharge plane Hb1 (ink discharge surface) of the discharge head H from the suction hole 72 (head suction cleaning in step S104). Therefore, the head facing plane 71 and the suction hole 72 of the suction block 7 are contaminated by the ink. Therefore, the suction block 7 is cleaned as follows.

[0062] That is, the cleaning liquid is supplied to the head facing plane 71, and the dummy plane 571 (cleaning auxiliary surface) of the dummy block 57a (cleaning auxiliary member) facing the head facing plane 71 comes into contact with this cleaning liquid. As a result, the cleaning liquid is spread over the head facing plane 71 by the dummy plane 571. In this way, the cleaning liquid can be spread over a wide range of the head facing plane 71 to clean the head facing plane 71. Further, the cleaning liquid spread over the head facing plane 71 is sucked from the suction holes 72 of the suction block 7. Therefore, the suction holes 72 can be cleaned by the cleaning liquid passing through the suction holes 72 during suction. In this way, reliable cleaning can be performed on both the head facing plane 71 and the suction holes 72 of the suction block 7. At this time, the removal of the ink supplied to the head facing plane 71 is performed by the suction holes 72 of the suction block 7. That is, the suction holes 72 have both functions of removing the ink from the discharge head H and removing the cleaning liquid from the head facing plane 71. Therefore, there is no need to separately provide a mechanism for removing the cleaning liquid, and the suction block 7 can be cleaned with a simple mechanism. In this way, it is possible to reliably perform the removal of the ink from the suction block 7 that sucks the ink from the discharge head H with a simple mechanism.

[0063] Further, a supply hole 73 is opened in the head facing plane 71, and the cleaning liquid supply unit 82 supplies the cleaning liquid to the head facing plane 71 from the supply hole 73. In such a configuration, the cleaning liquid is supplied from the supply hole 73 opened in the head facing plane 71 of the suction block 7. In other words, the suction block 7 supplies the cleaning liquid to the head facing plane 71 by itself. In this way, the simplification of the mechanism can be more reliably achieved.

[0064] Further, the ejection head H and the dummy block 57a are arranged in the horizontal direction Y and are located in the head cleaning region Rh. The height of the head facing plane 71 of the suction block 7 and the height of the head facing plane 71 of the suction block 7 located in the self-cleaning region Rs are the same. This is because the protruding plane Hb2 of the ejection head H with which the head facing plane 71 of the suction block 7 abuts in the head cleaning region Rh and the dummy plane 571 of the dummy block 57a with which the head facing plane 71 of the suction block 7 abuts in the self-cleaning region Rs are flush. On the other hand, the suction block 7 executes head suction cleaning (head cleaning) in the head cleaning region Rh and then moves horizontally in the Y direction from the head cleaning region Rh to the self-cleaning region Rs to execute self-cleaning in the self-cleaning region Rs (steps S104 to S105). With such a configuration, it is possible to smoothly shift from head suction cleaning to self-cleaning by a simple operation of moving the suction block 7 in the horizontal direction Y without changing the height of the suction block 7.

[0065] Also, in the horizontal direction Y, a dummy block 57b (positioning member) is provided on the side opposite to the dummy block 57a with respect to the ejection head H. This dummy block 57b has a dummy plane 571 (contact surface) provided with respect to the height of the head facing plane 71 of the suction block 7 located in the head cleaning region Rh. In other words, the protruding plane Hb2 of the ejection head H and the dummy plane 571 of the dummy block 57b are flush. Then, the linear motion mechanism 55 and the lifting mechanism E7 (drive unit) move the suction block 7 in the horizontal direction Y after bringing the head facing plane 71 of the suction block 7 into contact with the dummy plane 571 of the dummy block 57b from below, thereby moving the suction block 7 to the head cleaning region Rh (steps S103 to S104). With such a configuration, by bringing the head facing plane 71 of the suction block 7 into contact with the dummy plane 571 of the dummy block 57b, the head facing plane 71 can be positioned at the height when performing head suction cleaning and self-cleaning. Therefore, by bringing the head facing plane 71 into contact with the dummy plane 571 and then moving the suction block 7 in the horizontal direction Y, head suction cleaning and self-cleaning can be smoothly started.

[0066] As described above, in this embodiment, the printing apparatus 3 corresponds to an example of the "printing apparatus" of the present invention, the control unit 391 corresponds to an example of the "control unit" of the present invention, the drive control unit 391a corresponds to an example of the "drive control unit" of the present invention, the negative pressure control unit 391b corresponds to an example of the "negative pressure control unit" of the present invention, the supply control unit 391c corresponds to an example of the "supply control unit" of the present invention, the linear motion mechanism 55 and the lifting mechanism E7 cooperate to function as an example of the "drive unit" of the present invention, the dummy block 57a corresponds to an example of the "cleaning auxiliary member" of the present invention, the dummy plane 571 of the dummy block 57a corresponds to an example of the "cleaning auxiliary surface" of the present invention, the dummy block 57b corresponds to an example of the "positioning member" of the present invention, the dummy plane 571 of the dummy block 57b corresponds to an example of the "contact surface" of the present invention, the suction block 7 corresponds to an example of the "ink suction unit" of the present invention, the head facing plane 71 corresponds to an example of the "head facing surface" of the present invention, the suction hole 72 corresponds to an example of the "suction hole" of the present invention, the supply hole 73 corresponds to an example of the "supply hole" of the present invention, the cleaning liquid supply unit 82 corresponds to an example of the "cleaning liquid supply unit" of the present invention, the negative pressure applying unit 84 corresponds to an example of the "negative pressure applying unit" of the present invention, the discharge head H corresponds to an example of the "discharge head" of the present invention, the ink discharge plane Hb1 corresponds to an example of the "ink discharge surface" of the present invention, the nozzle Hc corresponds to an example of the "nozzle" of the present invention, the head cleaning area Rh corresponds to an example of the "head cleaning area" of the present invention, the self-cleaning area Rs corresponds to an example of the "self-cleaning area" of the present invention, the horizontal direction Y corresponds to an example of the "horizontal direction" of the present invention, the head suction cleaning in step S104 corresponds to an example of the "head cleaning" of the present invention, and the self-cleaning in steps S201 to S204 corresponds to an example of the "self-cleaning" of the present invention.

[0067] Note that the present invention is not limited to the above-described embodiment, and various modifications can be made other than those described above without departing from the spirit thereof. For example, the specific mode of executing self-cleaning can be variously changed. That is, the timing of performing self-cleaning is not limited to after head suction cleaning, and self-cleaning may be performed at other timings. Also, as shown below, the supply and suction of the cleaning liquid may be repeated.

[0068] FIG. 10 is a flowchart showing a modified example of self-cleaning. The flowchart of FIG. 10 is executed under the control of a supply control unit 391c and a negative pressure control unit 392b included in the control unit 391. In step S301, the head facing plane 71 of the suction block 7 abuts against the dummy plane 571 of the dummy block 57a. In this state, the supply of the cleaning liquid and the supply of the negative pressure are stopped.

[0069] Subsequently, the supply of the cleaning liquid to the head facing plane 71 through the supply hole 73 is started (step S302). In step S303, it is confirmed whether a predetermined first supply time has elapsed since the start of the supply of the cleaning liquid. By continuing to supply the cleaning liquid during the first supply time in this way, while supplying sufficient cleaning liquid to the head facing plane 71, the cleaning liquid can be spread over the head facing plane 71 by the dummy plane 571 of the dummy block 57a. When the first supply time has elapsed (YES in step S303), the supply of the cleaning liquid is stopped (step S304).

[0070] In step S305, the supply of the negative pressure to the suction hole 72 is started, and the suction of the cleaning liquid supplied to the head facing plane 71 is started. In step S306, it is confirmed whether a predetermined first suction time has elapsed since the start of the suction of the cleaning liquid. By continuing to suction the cleaning liquid during the first suction time in this way, the cleaning liquid can be surely removed from the head facing plane 71. When the first suction time has elapsed (YES in step S306), the supply of the negative pressure is stopped and the suction of the cleaning liquid is stopped (step S307).

[0071] In step S308, it is determined whether the number of executions of steps S302 to S307 has reached a predetermined number of times. Here, the predetermined number of times is one or more times. In particular, by setting the predetermined number of times to a plurality of times, steps S302 to S307 can be repeatedly performed to surely remove the ink from the head facing plane 71 and the suction holes 72 of the suction block 7. When the number of executions is less than the predetermined number of times (in the case of "NO" in step S308), the process returns to step S302, and when the number of executions is equal to the predetermined number of times (in the case of "YES" in step S308), the process proceeds to step S309.

[0072] In step S309, the supply of the cleaning liquid to the head facing plane 71 through the supply hole 73 is started. In step S310, it is confirmed whether a predetermined second supply time has elapsed since the start of the supply of the cleaning liquid. By continuing to supply the cleaning liquid during the second supply time in this way, while supplying sufficient cleaning liquid to the head facing plane 71, the cleaning liquid can be spread over the head facing plane 71 by the dummy plane 571 of the dummy block 57a. In particular, the second supply time is longer than the first supply time. Then, when the second supply time has elapsed (in the case of "YES" in step S310), the supply of the cleaning liquid is stopped (step S311).

[0073] In step S312, the supply of negative pressure to the suction holes 72 is started, and the suction of the cleaning liquid supplied to the head facing plane 71 is started. In step S313, it is confirmed whether a predetermined second suction time has elapsed since the start of the suction of the cleaning liquid. By continuing to suction the cleaning liquid during the second suction time in this way, the cleaning liquid can be surely removed from the head facing plane 71. In particular, the second suction time is longer than the first suction time. Then, when the second suction time has elapsed (in the case of "YES" in step S313), the supply of negative pressure is stopped, and the suction of the cleaning liquid is stopped (step S314).

[0074] In this modification example, the control unit 391 executes steps S302 to S307 (first self-cleaning) of supplying the cleaning liquid from the supply hole 73 for the first supply time and sucking the cleaning liquid from the suction hole 72 for the first suction time by the cleaning unit 8 (cleaning liquid supply unit), and steps S309 to S314 (second self-cleaning) of supplying the cleaning liquid from the supply hole 73 for the second supply time and sucking the cleaning liquid from the suction hole 72 for the second suction time by the cleaning unit 8. Specifically, after steps S302 to S307 are executed a predetermined number of times, S309 to S314 are executed. In particular, the second supply time is longer than the first supply time, and the second suction time is longer than the first suction time. With such a configuration, self-cleaning is executed at least twice (steps S302 to S307 and S309 to S314). At this time, the time (second supply time) during which the cleaning liquid is supplied in the subsequent self-cleaning (S309 to S314) is longer than the time (first supply time) during which the cleaning liquid is supplied in the previous self-cleaning (steps S302 to S307), and the time (second suction time) during which the cleaning liquid is sucked in the subsequent self-cleaning (S309 to S314) is longer than the time (first suction time) during which the cleaning liquid is sucked in the previous self-cleaning (steps S302 to S307). Thus, by finishing the cleaning of the suction block 7 (ink suction unit) by the self-cleaning (S309 to S314) in which the supply time and suction time of the cleaning liquid are relatively long, the removal of ink from the suction block 7 can be performed more reliably.

[0075] Note that modifications may be made to the flowchart of FIG. 10. For example, the second supply time may be set to be the same as or less than the first supply time, and the second suction time may be set to be the same as or less than the first suction time.

[0076] Also, the timing of supplying the cleaning liquid to the head-facing plane 71 of the suction block 7 may be appropriately changed. That is, in the above example, the cleaning liquid is supplied to the head-facing plane 71 in a state where the head-facing plane 71 of the suction block 7 is in contact with the dummy plane 571 of the dummy block 57a. However, the cleaning liquid may be supplied to the head-facing plane 71 in a state where the head-facing plane 71 of the suction block 7 is separated from the dummy plane 571 of the dummy block 57a, and then the head-facing plane 71 may be brought into contact with the dummy plane 571. Even by such an operation, the cleaning liquid can be spread over the head-facing plane 71 by the dummy plane 571.

[0077] Also, when supplying and sucking the cleaning liquid during the self-cleaning of the suction block 7, it is not always necessary for the head-facing plane 71 of the suction block 7 to be in contact with the dummy plane 571 of the dummy block 57a. That is, with a slight clearance from the dummy plane 571 of the dummy block 57a, the cleaning liquid may be supplied and sucked in a state where the head-facing plane 71 of the suction block 7 faces it.

[0078] Also, the specific configuration for supplying the cleaning liquid may be changed. For example, the supply hole for the cleaning liquid may be provided in the dummy block 57a instead of the suction block 7. In such a configuration, the cleaning unit 8 supplies the cleaning liquid from the supply hole that opens on the dummy plane 571 of the dummy block 57a to the head-facing plane 71 of the suction block 7.

[0079] Also, it is not essential to provide two dummy blocks 57a and 57b, and only one dummy block 57a may be provided.

[0080] Also, the placement location of the dummy block 57a is not limited to the above example and may be changed as appropriate, and it is not necessarily required to attach the dummy block 57a to the head unit 321.

[0081] Alternatively, by moving the ejection head H in the horizontal direction Y, head suction cleaning by the suction block 7 may be performed. In short, it is only necessary to relatively move the suction block 7 with respect to the ejection head H.

Industrial Applicability

[0082] The present invention is applicable to the entire technology of cleaning an ink suction unit that sucks ink adhering to an ejection head that ejects ink.

Explanation of Signs

[0083] 3…Printing apparatus 391…Control unit 55…Linear motion mechanism (drive unit) E7…Lifting mechanism (drive unit) 57a…Dummy block (cleaning auxiliary member) 57b…Dummy block (positioning member) 571…Dummy plane (cleaning auxiliary plane, contact plane) 7…Suction block (ink suction unit) 71…Head facing plane (head facing surface) 72…Suction hole 73…Supply hole 8…Cleaning unit 82…Cleaning liquid supply unit 84…Negative pressure applying unit 822…Liquid feed pump 823, 842, 846…On-off solenoid valve 844…Injector H…Ejection head Hb1…Ink ejection plane (ink ejection surface) Hc…Nozzle Rh…Head cleaning area Rs…Self-cleaning area Y…Horizontal direction S104…Head suction cleaning (head cleaning) S201~S204…Self-cleaning

Claims

1. A discharge head having an ink discharge surface through which a nozzle opens, for discharging ink from the nozzle; An ink suction unit having a head facing surface through which a suction hole opens, for sucking ink from the suction hole; A negative pressure applying unit for applying a negative pressure to the suction hole of the ink suction unit; A cleaning liquid supply unit for supplying a cleaning liquid to the head facing surface; A cleaning assisting member having a cleaning assisting surface; A drive unit for moving the ink suction unit between a head cleaning area where the head facing surface faces the ink discharge surface and a self-cleaning area where the head facing surface faces the cleaning assisting surface; A control unit for controlling the negative pressure applying unit, the cleaning liquid supply unit, and the drive unit; Comprising; The control unit: A negative pressure control unit for controlling the negative pressure applying unit; A drive control unit for controlling the drive unit; A supply control unit for controlling the cleaning liquid supply unit; Including; During head cleaning for cleaning the discharge head: The drive control unit controls the drive unit to move the ink suction unit to the head cleaning area, and further moves the ink suction unit horizontally within the head cleaning area while the head facing surface of the ink suction unit faces the ink discharge surface of the discharge head; The negative pressure control unit controls to activate the negative pressure applying unit, and generates a negative pressure in the suction hole of the ink suction unit during the horizontal movement of the ink suction unit within the head cleaning area, thereby sucking the ink adhering to the ink discharge surface from the suction hole; During self-cleaning for cleaning the ink suction unit: The drive control unit controls the drive unit to move the ink suction unit to the self-cleaning area, and in the self-cleaning area, makes the head facing surface of the ink suction unit face the cleaning assisting surface; The supply control unit controls the cleaning liquid supply unit to supply a cleaning liquid from the cleaning liquid supply unit to the head facing surface of the ink suction unit within the self-cleaning area; The negative pressure control unit controls to activate the negative pressure applying unit, and generates a negative pressure in the suction hole of the ink suction unit, thereby sucking the cleaning liquid supplied to the head facing surface from the suction hole while bringing the cleaning liquid into contact with the cleaning assisting surface; A printing apparatus.

2. A supply hole opens in the head facing surface; The printing apparatus according to claim 1, wherein the cleaning liquid supply unit supplies the cleaning liquid to the head facing surface through the supply hole.

3. The ejection head and the cleaning auxiliary member are arranged in a predetermined horizontal direction. The height of the head facing surface of the ink suction portion located in the head cleaning region is the same as the height of the head facing surface of the ink suction portion located in the self-cleaning region. The drive control unit controls the drive unit to move the ink suction unit to the head cleaning region to cause the ink suction unit to perform head cleaning, and then controls the drive unit to move the ink suction unit from the head cleaning region to the self-cleaning region to perform self-cleaning. The printing apparatus according to claim 1 or 2.

4. In the horizontal direction, the printing apparatus further includes a positioning member disposed on the side opposite to the cleaning auxiliary member with respect to the ejection head. The positioning member has a contact surface provided with respect to the height of the head facing surface of the ink suction portion located in the head cleaning region. The drive control unit controls the drive unit to move the ink suction unit to a position where the head facing surface thereof abuts against the contact surface of the positioning member, and then moves the ink suction unit in the horizontal direction to move the ink suction unit to the head cleaning region. The printing apparatus according to claim 3.

5. The control unit further includes a supply control unit that controls the cleaning liquid supply unit. The supply control unit controls the cleaning liquid supply unit so that the cleaning liquid is supplied from the cleaning liquid supply unit for a first supply time. After the negative pressure control unit performs the first self-cleaning one or more times to control the negative pressure applying unit so that the cleaning liquid is sucked from the suction hole for a first suction time. The supply control unit controls the cleaning liquid supply unit so that the cleaning liquid is supplied from the cleaning liquid supply unit for a second supply time longer than the first supply time. The negative pressure control unit performs a second self-cleaning to control the negative pressure applying unit so that the cleaning liquid is sucked from the suction hole for a second suction time longer than the first suction time. The printing apparatus according to any one of claims 1 to 4.

6. The ink ejection surface of the ejection head that ejects ink from a nozzle opening to the ink ejection surface, and the head facing surface of the ink suction unit that sucks ink from a suction hole opening to the head facing surface face each other. The ink suction unit is moved to a head cleaning area, and further, within the head cleaning area, the head facing surface of the ink suction unit faces the ink ejection surface of the ejection head, and the ink suction unit moves horizontally within the head cleaning area. During the horizontal movement of the ink suction unit within the head cleaning area, a negative pressure is generated in the suction hole of the ink suction unit to suck the ink adhering to the ink ejection surface from the suction hole. Moving the ink suction unit to a self-cleaning area where the head facing surface faces the cleaning assist surface of the cleaning assist member. Supplying a cleaning liquid to the head facing surface. Contacting the cleaning assist surface of the cleaning assist member facing the head facing surface with the cleaning liquid supplied to the head facing surface. Sucking the cleaning liquid on the head facing surface from the suction hole. An ink suction unit cleaning method comprising the above steps.

7. An ejection head having an ink ejection surface where a nozzle opens and ejecting ink from the nozzle. An ink suction unit having a head facing surface where a suction hole opens and sucking ink from the suction hole. A negative pressure applying unit that applies a negative pressure to the suction hole of the ink suction unit. A cleaning liquid supply unit that supplies a cleaning liquid to the head facing surface. A cleaning assist member having a cleaning assist surface. A drive unit that moves the ink suction unit between a head cleaning area where the head facing surface faces the ink ejection surface and a self-cleaning area where the head facing surface faces the cleaning assist surface. A control unit that controls the negative pressure applying unit, the cleaning liquid supply unit, and the drive unit. Comprising: The control unit: A negative pressure control unit that controls the negative pressure applying unit. A drive control unit that controls the drive unit. A supply control unit that controls the cleaning liquid supply unit. Including: During head cleaning of the ejection head: The drive control unit controls the drive unit to move the ink suction unit to the head cleaning area, and further, within the head cleaning area, the head facing surface of the ink suction unit faces the ink ejection surface of the ejection head while moving the ink suction unit. The negative pressure control unit controls to activate the negative pressure applying unit, and generates a negative pressure in the suction holes of the ink suction unit, thereby sucking the ink adhering to the ink ejection surface from the suction holes. During self-cleaning for cleaning the ink suction unit, the drive control unit controls the drive unit to move the ink suction unit to the self-cleaning area, and in the self-cleaning area, makes the head facing surface of the ink suction unit face the cleaning auxiliary surface. The supply control unit controls the cleaning liquid supply unit to supply the cleaning liquid from the cleaning liquid supply unit to the head facing surface of the ink suction unit in the self-cleaning area. The negative pressure control unit controls to activate the negative pressure applying unit, and generates a negative pressure in the suction holes of the ink suction unit, thereby sucking the cleaning liquid from the suction holes while bringing the cleaning liquid supplied to the head facing surface into contact with the cleaning auxiliary surface. The ejection head and the cleaning auxiliary member are arranged in a predetermined horizontal direction. The height of the head facing surface of the ink suction unit located in the head cleaning area is the same as the height of the head facing surface of the ink suction unit located in the self-cleaning area. A printing apparatus, wherein the drive control unit controls the drive unit to move the ink suction unit to the head cleaning area to perform head cleaning on the ink suction unit, and then controls the drive unit to move the ink suction unit from the head cleaning area to the self-cleaning area for self-cleaning.

8. An ejection head having an ink ejection surface where nozzles open, for ejecting ink from the nozzles, an ink suction unit having a head facing surface where suction holes open, for sucking ink from the suction holes, a negative pressure applying unit for applying a negative pressure to the suction holes of the ink suction unit, a cleaning liquid supply unit for supplying a cleaning liquid to the head facing surface, a cleaning auxiliary member having a cleaning auxiliary surface, a drive unit for moving the ink suction unit between a head cleaning area where the head facing surface faces the ink ejection surface and a self-cleaning area where the head facing surface faces the cleaning auxiliary surface, a control unit for controlling the negative pressure applying unit, the cleaning liquid supply unit, and the drive unit, and comprising the control unit is a negative pressure control unit for controlling the negative pressure applying unit, a drive control unit for controlling the drive unit, a supply control unit for controlling the cleaning liquid supply unit, and includes During head cleaning for cleaning the ejection head, The drive control unit controls the drive unit to move the ink suction unit to the head cleaning area, and further moves the ink suction unit within the head cleaning area while the head-facing surface of the ink suction unit faces the ink ejection surface of the ejection head. The negative pressure control unit controls to activate the negative pressure applying unit, generates a negative pressure in the suction holes of the ink suction unit, and sucks the ink adhering to the ink ejection surface from the suction holes. During self-cleaning of the ink suction unit, the drive control unit controls the drive unit to move the ink suction unit to the self-cleaning area, and within the self-cleaning area, makes the head-facing surface of the ink suction unit face the cleaning auxiliary surface. The supply control unit controls the cleaning liquid supply unit to supply the cleaning liquid from the cleaning liquid supply unit to the head-facing surface of the ink suction unit within the self-cleaning area. The negative pressure control unit controls to activate the negative pressure applying unit, generates a negative pressure in the suction holes of the ink suction unit, and sucks the cleaning liquid from the suction holes while bringing the cleaning liquid supplied to the head-facing surface into contact with the cleaning auxiliary surface. The control unit further includes a supply control unit that controls the cleaning liquid supply unit. The supply control unit controls the cleaning liquid supply unit so that the cleaning liquid is supplied from the cleaning liquid supply unit for a first supply time. After the negative pressure control unit performs the first self-cleaning one or more times to control the negative pressure applying unit so that the cleaning liquid is sucked from the suction holes for a first suction time, The supply control unit controls the cleaning liquid supply unit so that the cleaning liquid is supplied from the cleaning liquid supply unit for a second supply time longer than the first supply time. A printing apparatus in which the negative pressure control unit performs a second self-cleaning to control the negative pressure applying unit so that the cleaning liquid is sucked from the suction holes for a second suction time longer than the first suction time.

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