Printing device and mask cleaning method

Abstract

This printing device prints solder on a substrate via a mask, and comprises: a cleaning member that has a cleaning surface and cleans the mask by moving a cleaning sheet, which is supplied to a cleaning region on the cleaning surface, in a cleaning direction along the mask while bringing the cleaning sheet into contact with the mask; a sheet conveyance unit that conveys the cleaning sheet in a prescribed conveyance direction and supplies the cleaning sheet to the cleaning surface; a cleaning liquid application unit that applies a cleaning liquid to the cleaning sheet; and a control unit that controls the cleaning liquid application unit to apply the cleaning liquid to the cleaning sheet in an application region upstream of the cleaning region in the conveyance direction, then controls the sheet conveyance unit to convey the cleaning sheet in the conveyance direction, thereby conveying the cleaning liquid applied to the cleaning sheet to the cleaning region.

Description

Printing apparatus and mask cleaning method

[0001] The present invention relates to a mask cleaning technique for cleaning a mask used for printing solder onto a substrate.

[0002] A printing apparatus is generally used in which a mask having openings corresponding to a print pattern is overlaid on a substrate from above, and solder supplied to the upper surface of the mask is printed onto the substrate through the print pattern. In such a printing apparatus, as disclosed in Patent Documents 1 to 3, the mask is appropriately cleaned.

[0003] Japanese Patent Application Laid-Open No. 10-235843, Japanese Patent Application Laid-Open No. 8-1920, Japanese Patent No. 6760823

[0004] Specifically, solder adhering to the mask can be removed by moving a cleaning sheet supported on the cleaning surface of a cleaning member along the mask while bringing the cleaning sheet into contact with the mask from the lower side. At this time, the cleaning effect of the mask can be enhanced by applying a cleaning liquid to the cleaning sheet supported on the cleaning surface. Specifically, a cleaning liquid application unit such as a nozzle may be opposed to the cleaning sheet supported on the cleaning surface, and the cleaning liquid may be applied by the cleaning liquid application unit. However, in order to enable application of the cleaning liquid, it is necessary to cause the cleaning liquid application unit to face the cleaning surface of the cleaning member from above while avoiding interference between the cleaning liquid application unit and the mask. For this reason, the locations where the cleaning liquid application unit can be disposed have been limited.

[0005] The present invention has been made in view of the above problems, and an object of the present invention is to enable free arrangement of a cleaning liquid application unit that applies cleaning liquid to a cleaning sheet in a technique for cleaning a mask while supporting the cleaning sheet coated with the cleaning liquid on the cleaning surface of a cleaning member.

[0006] The printing apparatus according to the present invention is a printing apparatus for printing solder onto a substrate via a mask, and comprises a cleaning member having a cleaning surface and cleaning the mask by moving a cleaning sheet supplied to a cleaning area on the cleaning surface in a cleaning direction along the mask while bringing it into contact with the mask; a sheet transport unit that transports the cleaning sheet in a predetermined transport direction to supply the cleaning sheet to the cleaning surface; a cleaning liquid application unit that applies cleaning liquid to the cleaning sheet; and a control unit that controls the cleaning liquid application unit to apply cleaning liquid to the cleaning sheet in an application area upstream of the cleaning area in the transport direction, and then controls the sheet transport unit to transport the cleaning sheet in the transport direction to transport the cleaning liquid applied to the cleaning sheet to the cleaning area.

[0007] The present invention relates to a mask cleaning method for cleaning a mask used to print solder onto a substrate via the mask, comprising the steps of: a cleaning solution application unit applying a cleaning solution to a cleaning sheet in an application area; a sheet transport unit transporting the cleaning sheet in a transport direction to transport the cleaning sheet coated with the cleaning solution to a cleaning area on the cleaning surface of a cleaning member; and a cleaning member cleaning the mask by moving the cleaning sheet supplied to the cleaning area in a cleaning direction along the mask while bringing it into contact with the mask.

[0008] In the present invention (printing apparatus and mask cleaning method) configured as described above, the cleaning solution application unit applies the cleaning solution to the cleaning sheet in the application area, and then the sheet transport unit transports the cleaning sheet in the transport direction, so that the cleaning sheet coated with the cleaning solution is transported to the cleaning area on the cleaning surface of the cleaning member. In this way, the cleaning solution is applied to the cleaning sheet in an application area separate from the cleaning area on the cleaning surface of the cleaning member, and then the cleaning solution applied to the cleaning sheet is transported to the cleaning area. That is, the application area for applying the cleaning solution and the cleaning area for cleaning the mask are separated. Therefore, the cleaning solution application unit that applies the cleaning solution in the application area can be easily positioned away from the cleaning area. Thus, in a technology for cleaning a mask while supporting a cleaning sheet coated with cleaning solution on the cleaning surface of the cleaning member, the cleaning solution application unit that applies the cleaning solution to the cleaning sheet can be freely positioned.

[0009] Alternatively, the cleaning member, sheet transport unit, and cleaning solution application unit may be unitized as a cleaning unit and movable in the cleaning direction. The control unit may be configured to clean the mask by moving the cleaning unit in the cleaning direction while bringing the cleaning sheet coated with cleaning solution into contact with the mask in the cleaning area. In such a configuration, it is not necessary to move the cleaning member to the cleaning solution application unit for the application of the cleaning solution. Therefore, the application of the cleaning solution can be completed quickly, and the mask can be cleaned efficiently.

[0010] Alternatively, the cleaning solution application unit may be positioned lower than the mask, and the printing apparatus may be configured so that it is separated from the mask during cleaning. This configuration prevents interference between the cleaning solution application unit and the mask.

[0011] Alternatively, the cleaning sheet may have a contact surface and a non-contact surface opposite to the contact surface, with the contact surface in contact with the mask, and the cleaning solution application unit may be configured to apply the cleaning solution to the contact surface. In such a configuration, the cleaning solution can be supplied firmly to the mask, allowing for effective cleaning.

[0012] Furthermore, the control unit may be configured to apply the cleaning solution to the cleaning sheet in the application area multiple times at predetermined time intervals, and to move the cleaning sheet a predetermined distance in the transport direction during each time interval. With such a configuration, the cleaning solution can be applied to the cleaning sheet over a wide area in the transport direction.

[0013] Furthermore, the control unit may be configured to apply the cleaning solution to the cleaning sheet in the application area while transporting the cleaning sheet in the transport direction. In such a configuration, the cleaning solution can be applied to the cleaning sheet over a wide area in the transport direction.

[0014] Furthermore, the control unit may configure the printing apparatus to transport the cleaning solution applied to the cleaning sheet to the cleaning area so that the area where the cleaning solution is present on the cleaning sheet is concentrated within the cleaning area. In such a configuration, the cleaning solution can be applied only to the parts of the mask that are effective for cleaning, thereby reducing the amount of cleaning solution consumed.

[0015] Furthermore, the printing apparatus may be configured such that the area of ​​presence is biased towards the downstream side in the cleaning direction within the cleaning area. In such a configuration, the cleaning solution can be applied only to the parts of the mask that are effective for cleaning, thereby reducing the amount of cleaning solution consumed.

[0016] Furthermore, the printing apparatus may be configured to include a suction unit that sucks up suction holes opening on the cleaning surface, and the control unit may perform a success / failure check based on the pressure at the suction holes when the suction unit sucks up the suction holes, in order to confirm whether the cleaning preparation, which involves applying cleaning solution to a cleaning sheet and transporting it to the cleaning area, is successful. In such a configuration, the success or failure of the cleaning preparation can be confirmed.

[0017] Furthermore, the printing apparatus may be configured such that, upon detecting a failure in the cleaning preparation, the control unit changes the amount of cleaning solution applied to the cleaning sheet in the application area. In such a configuration, it becomes possible to successfully complete the cleaning preparation by changing the amount of cleaning solution applied.

[0018] Furthermore, the printing apparatus may be configured such that the control unit determines the amount of cleaning solution to be applied based on the result of determining whether or not the cleaning preparation will be successful by changing the amount of cleaning solution applied. In such a configuration, the amount of cleaning solution to be applied to the cleaning sheet in the application area can be appropriately determined, thereby ensuring the cleaning preparation is successful.

[0019] Furthermore, the printing device may be configured to include an error notification unit that notifies the operator of errors, and the control unit may cause the error notification unit to notify the operator of an error if it determines that the cleaning preparation will not be successful even if the amount of cleaning solution applied is changed. In such a configuration, the error notification can prompt the operator to perform the necessary maintenance work.

[0020] Furthermore, the printing apparatus may be configured such that, upon detecting a failure in the cleaning preparation, the control unit changes the amount of cleaning sheet being transported to deliver the cleaning solution applied to the cleaning sheet to the cleaning area. In such a configuration, it becomes possible to successfully complete the cleaning preparation by changing the amount of cleaning sheet being transported.

[0021] Furthermore, the printing device may be configured such that the control unit determines the amount of material to be transported based on the result of determining whether or not the cleaning preparation will be successful by changing the amount of material to be transported. In such a configuration, the amount of cleaning sheets to be transported can be appropriately determined, and the cleaning preparation can be successfully completed.

[0022] Furthermore, the printing device may be configured to include an error notification unit that notifies the operator of errors, and the control unit may cause the error notification unit to notify the operator of an error if it determines that cleaning preparation will not be successful even if the amount of cleaning sheets transported is changed. In such a configuration, the error notification can prompt the operator to perform necessary maintenance work.

[0023] According to the present invention, in a technique for cleaning a mask while supporting a cleaning sheet coated with a cleaning solution on the cleaning surface of a cleaning member, it becomes possible to freely position the cleaning solution application portion that applies the cleaning solution to the cleaning sheet.

[0024] A schematic front view of the printing apparatus according to the present invention. A block diagram showing the electrical configuration of the printing apparatus in Figure 1. A schematic plan view showing an example of a cleaning unit. A schematic front view showing an example of a cleaning unit. A schematic perspective view showing an example of a dispenser. A flowchart showing a first example of a mask cleaning operation performed by the printing apparatus. A schematic diagram showing the operation performed in the first example of the mask cleaning operation in Figure 6A. A flowchart showing a second example of a mask cleaning operation performed by the printing apparatus. A schematic diagram showing the operation performed in the second example of the mask cleaning operation in Figure 7A. A schematic diagram showing the operation performed in the second example of the mask cleaning operation in Figure 7A. A schematic perspective view showing an example of a suction unit that the printing apparatus may be equipped with. A flowchart showing an example of a cleaning preparation success / failure confirmation that can be performed using the suction unit in Figure 8A. A flowchart showing a first example of cleaning preparation condition optimization. A flowchart showing a second example of cleaning preparation condition optimization. A flowchart showing a third example of cleaning preparation condition optimization. A flowchart showing a fourth example of cleaning preparation condition optimization. A flowchart showing the fourth example of optimizing cleaning preparation conditions. A diagram schematically showing variations in the range of presence of solvent applied to the cleaning sheet within the cleaning area. A diagram schematically showing variations in the range of presence of solvent applied to the cleaning sheet within the cleaning area. A diagram schematically showing variations in the arrangement of dispensers. A diagram schematically showing variations in the arrangement of dispensers.

[0025] Figure 1 is a schematic front view of the printing apparatus according to the present invention, and Figure 2 is a block diagram showing the electrical configuration of the printing apparatus in Figure 1. In Figure 1 and the following figures, the horizontal direction X, the horizontal direction Y perpendicular to the X direction, and the vertical direction Z are indicated as appropriate. The printing apparatus 1 comprises a mask holding unit 2 that holds a mask M, a substrate holding unit 4 positioned below the mask M, and a squeegee unit 6 positioned above the mask M. Furthermore, the printing apparatus 1 comprises a main control unit 10 composed of a CPU (Central Processing Unit) and RAM (Random Access Memory), etc., and a storage unit 11 composed of an HDD (Hard Disk Drive), etc. The main control unit 10 controls each unit 4 and 6 according to the printing program stored in the storage unit 11, so that the substrate holding unit 4 brings the substrate B into contact with the mask M from below, while the tip of the squeegee 61 of the squeegee unit 6 slides in the X direction on the upper surface of the mask M. As a result, the solder supplied to the upper surface of the mask M is printed on the substrate B via a printing pattern that penetrates the mask M.

[0026] Furthermore, the printing device 1 includes a drive control unit 12 and a valve control unit 13 that control the operation of each movable part, and the main control unit 10 controls the movable parts of units 4 and 6 by the drive control unit 12 and the valve control unit 13. In addition, the printing device 1 includes a display unit 14, which is composed of, for example, a liquid crystal display, and an input unit 15, which is composed of input devices such as a keyboard and a mouse. Therefore, the operator can check the operating status of the printing device 1 by checking the display contents of the display unit 14, and input commands to the printing device 1 by operating the input unit 15. The display unit 14 and the input unit 15 may be integrated using a touch panel. The printing device 1 also includes a communication unit 16 that performs communication with an external device, and this communication unit 16 receives, for example, the above-mentioned printing program from an external server and stores it in the storage unit 11.

[0027] The mask holding unit 2 has a clamp member 21, and the mask M is detachably attached to the clamp member 21 via a frame 22 provided on its periphery. In this way, the flat-shaped mask M is held by the mask holding unit 2 parallel to the XY plane (i.e., horizontally). The mask M has a rectangular shape in plan view and has through holes (printing patterns) in a shape corresponding to the printing pattern on the substrate B.

[0028] The substrate holding unit 4 is positioned below the mask M held by the mask holding unit 2 and is responsible for aligning the position of the substrate B with respect to the mask M. The substrate holding unit 4 includes a pair of conveyors 41 for transporting the substrate B, a substrate holding section 42 for holding the substrate B received from the conveyors 41, and a flat, movable table 43 that supports the conveyors 41 and the substrate holding section 42.

[0029] A pair of conveyors 41 are arranged parallel to the Y direction with a gap in the X direction, and their upper surfaces support both ends of the substrate B in the X direction from below. The substrate holding unit 4 is also provided with a conveyor drive unit M41 that drives these conveyors 41. When the conveyor drive unit M41 receives a command from the drive control unit 12 and drives each conveyor 41, each conveyor 41 transports the substrate B in the Y direction, thereby loading or unloading the substrate B to or from the printing device 1.

[0030] The substrate holding section 42 has a flat lifting table 421 and a sliding column 422 that can slide in the Z direction relative to the movable table 43, with the lifting table 421 supported by the upper end of the sliding column 422. Multiple backup pins P are erected in the Z direction on the upper surface of the lifting table 421 and are arranged with spacing in the X and Y directions. Furthermore, the substrate holding section 42 is provided with a backup drive unit M423, and the backup drive unit M423, upon receiving a command from the drive control unit 12, raises and lowers the sliding column 422, thereby raising and lowering the backup pins P together with the lifting table 421. For example, when a substrate B is loaded onto the conveyor 41, the backup drive unit M423 positions the upper end of each backup pin P below the upper surface of the conveyor 41. Then, when the conveyor 41 loads the substrate B directly above the backup pins P, the backup drive unit M423 raises the backup pins P, causing their upper ends to protrude above the upper surface of the conveyor 41. As a result, the upper ends of the backup pins P come into contact with the lower surface of the substrate B, pushing up the substrate B, and the substrate B is passed from the top surface of the conveyor 41 to the upper ends of each backup pin P.

[0031] Furthermore, the substrate holding section 42 includes a pair of clamp plates 424 arranged above the pair of conveyors 41 with a gap in the X direction, and a plate drive section M424 that drives at least one of these clamp plates 424 in the X direction. The upper surfaces of each clamp plate 424 are planes parallel to the X and Y directions and are located at the same height. The plate drive section M424 adjusts the air supplied to the clamp plates 424 by opening and closing valves in response to commands from the valve control section 13. This drives the clamp plates 424 in the X direction.

[0032] Then, the drive control unit 12 raises the substrate B on the backup pin P to between the pair of clamp plates 424, and the valve, which has received a command from the valve control unit 13, operates to narrow the distance between these clamp plates 424, so that the substrate B is clamped by these clamp plates 424 from the X direction (horizontal direction).

[0033] Furthermore, the substrate holding unit 4 has a table drive mechanism 44 that drives the movable table 43. This table drive mechanism 44 includes an X-axis table 441, a Y-axis table 442 mounted on the upper surface of the X-axis table 441, an R-axis table 443 mounted on the upper surface of the Y-axis table 442, and a ball screw 444 that raises and lowers the movable table 43 relative to the R-axis table 443. Furthermore, the table drive mechanism 44 includes an X-axis drive unit M441 that drives the X-axis table 441 in the X direction, a Y-axis drive unit M442 that drives the Y-axis table 442 in the Y direction, an R-axis drive unit M443 that drives the R-axis table 443 in the R direction (rotational direction around an axis parallel to the Z direction), and a Z-axis drive unit M444 that drives the movable table 43 in the Z direction by rotating the ball screw 444. Therefore, the drive control unit 12 can drive the conveyor 41 and substrate holding unit 42, which are arranged on the movable table 43, in the X, Y, Z, and R directions by controlling each of the drive units M441 to M444. For example, when positioning a transported substrate B relative to the mask M, the drive control unit 12 adjusts the position of the substrate B clamped to the clamp plate 424 in the X and Y directions using the X, Y, and R axis drive units M441 to M443, and in the Z direction using the Z axis drive unit M444. As a result, the upper surfaces of the clamp plate 424 and the substrate B come into contact with the lower surface of the mask M.

[0034] In this process, the main control unit 10 aligns the mask M and the substrate B based on the results of imaging them. Specifically, the printing apparatus 1 includes a recognition camera 5 and an X-axis drive unit Mx that drives the recognition camera 5 in the X direction. The recognition camera 5 is positioned at the height between the substrate B and the mask M when the substrate B is separated from the mask M downwards. The X-axis drive unit Mx has an X-axis ball screw provided parallel to the X direction and an X-axis motor that rotates the X-axis ball screw, and the recognition camera 5 is attached to the nut of the X-axis ball screw. Therefore, the main control unit 10 can move the recognition camera 5 in the X direction via the X-axis drive unit Mx through the drive control unit 12, and image the fiducial marks of the substrate B and the mask M with the recognition camera 5 as it passes between the substrate B and the mask M. The main control unit 10 then controls the substrate holding unit 4 based on the imaging results of these fiducial marks to align the mask M and the substrate B.

[0035] Furthermore, the printing apparatus 1 includes a cleaning unit 8 located below the mask M, and a cleaning control unit 17 that controls the cleaning unit 8. The cleaning unit 8 is attached to a nut of the X-axis drive unit Mx. The drive control unit 12 allows the cleaning unit 8 to move in the X direction by the X-axis drive unit Mx. The main control unit 10 operates the cleaning unit 8 using the drive control unit 12 and the cleaning control unit 17, pressing the cleaning sheet S (cleaning paper) against the mask M and sliding the cleaning sheet S in the X direction (cleaning direction) relative to the mask M. This performs cleaning by wiping away solder adhering to the underside of the mask M with the cleaning sheet S.

[0036] Figure 3 is a schematic plan view showing an example of a cleaning unit, and Figure 4 is a schematic front view showing an example of a cleaning unit. The cleaning unit 8 comprises a housing 80 and a dispensing roller 81 and a winding roller 82 rotatably supported by the housing 80. Both the dispensing roller 81 and the winding roller 82 are arranged parallel to the Y direction and spaced apart from each other in the X direction. The dispensing roller 81 and the winding roller 82 rotate around a rotation axis parallel to the Y direction, thereby conveying the cleaning sheet S in a roll-to-roll manner in the conveying direction Ds from the dispensing roller 81 to the winding roller 82. In other words, the dispensing roller 81 supports a new cleaning sheet S wound into a roll, and the winding roller 82 winds up the cleaning sheet S that has been dispensed from the dispensing roller 81 and used to clean the mask M into a roll.

[0037] The cleaning unit 8 also includes a torque limiter 83 attached to the feed roller 81 and a brake 84 attached to the feed roller 81 via the torque limiter 83. The cleaning unit 8 allows the feed roller 81 to rotate by turning off the brake 84, and prohibits the feed roller 81 from rotating by turning on the brake 84. The cleaning unit 8 also includes a winding motor 85 attached to the winding roller 82, and the winding motor 85 rotates the winding roller 82 to transport the cleaning sheet S in the transport direction Ds from the feed roller 81 to the winding roller 82.

[0038] As described above, a sheet transport unit Ts, consisting of a feed roller 81, a winding roller 82, a torque limiter 83, a brake 84, and a winding motor 85, is provided in the cleaning unit 8. The sheet transport unit Ts transports the cleaning sheet S in the transport direction Ds by turning off the brake 84 and rotating the winding roller 82 with the winding motor 85, thereby winding the cleaning sheet S with the winding roller 82 and unwinding the cleaning sheet S from the feed roller 81. The sheet transport unit Ts also stops the cleaning sheet S by turning on the brake 84 and stopping the winding motor 85. The main control unit 10 controls the sheet transport unit Ts via the cleaning control unit 17 to transport or stop the cleaning sheet S in the transport direction Ds.

[0039] Furthermore, the cleaning unit 8 includes a cleaning head 86 that presses the cleaning sheet S against the mask M from below, and a head drive unit Mz that drives the cleaning head 86 in the Z direction. The cleaning head 86 is positioned between the feed roller 81 and the winding roller 82 in the X direction and has a pressing surface 861 that faces the mask M from below via the cleaning sheet S. The pressing surface 861 is rectangular in shape and parallel to the XY plane (i.e., horizontal). The head drive unit Mz is composed of an actuator or motor, and the main control unit 10 can drive the cleaning head 86 in the Z direction by operating the head drive unit Mz via the cleaning control unit 17.

[0040] The pressing surface 861 of the cleaning head 86 contacts the cleaning sheet S from below between the dispensing roller 81 and the winding roller 82 in the transport direction Ds. In this way, the cleaning sheet S is supported by the pressing surface 861. The cleaning sheet S, which is dispensed from the dispensing roller 81 in the transport direction Ds, rises toward the upstream end of the pressing surface 861 in the transport direction Ds. Having reached the upstream end of the pressing surface 861, the cleaning sheet S moves toward the transport direction Ds along the horizontal pressing surface 861 and reaches the downstream end of the pressing surface 861 in the transport direction Ds. The cleaning sheet S, which is transported toward the transport direction Ds from the downstream end of the pressing surface 861, descends toward the winding roller 82 from the downstream end of the pressing surface 861.

[0041] As shown in the "Pressing State" column of Figure 4, the head drive unit Mz positions the pressing surface 861 of the cleaning head 86 at the pressing position Hh, thereby pressing the cleaning sheet S against the mask M from below with the pressing surface 861. In this state, the main control unit 10 moves the cleaning unit 8 in the X direction using the X-axis drive unit Mx, causing the cleaning sheet S on the pressing surface 861 to slide against the lower surface of the mask M, thereby performing cleaning. During this cleaning, the brake 84 is engaged, preventing the rotation of the feed roller 81, and the cleaning sheet S is stopped relative to the pressing surface 861. This cleaning is performed each time a printing operation is executed on one substrate B.

[0042] Furthermore, as shown in the column of "separated state" in FIG. 4, the head drive unit Mz positions the pressing surface 861 of the cleaning head 86 at a separated position Hl lower than the pressing position Hh. The pressing surface 861 located at the separated position Hl is separated downward from the mask M. That is, by positioning the pressing surface 861 at the separated position Hl, the pressing of the cleaning sheet S by the pressing surface 861 is released. In this state, the main control unit 10 can execute a supply operation of conveying the cleaning sheet S in the conveying direction Ds by the sheet conveying unit Ts and supplying a new cleaning sheet S to the pressing surface 861.

[0043] The cleaning sheet S is made of, for example, paper or gauze, and has water absorbency for absorbing liquid and water retention for retaining the absorbed liquid. This cleaning sheet S has a front surface S1 and a back surface S2 opposite to the front surface S1. The front surface S1 of the cleaning sheet S supported by the pressing surface 861 faces upward, and the back surface S2 of the cleaning sheet S faces downward. That is, the pressing surface 861 supports the back surface S2 of the cleaning sheet S from below. Further, in the pressed state, the pressing surface 861 presses the front surface S1 of the cleaning sheet S against the mask M from below. Therefore, the mask M is cleaned by wiping the mask M with the front surface S1 of the cleaning sheet S that is in contact with the mask M.

[0044] The cleaning unit 8 includes a dispenser 87 (FIG. 5) that discharges a solvent V (FIG. 6B). FIG. 5 is a perspective view schematically showing an example of the dispenser. The dispenser 87 has a dispenser main body 871 attached to a housing 80. The dispenser main body 871 has a solvent discharge surface 872 at the bottom of the dispenser main body 871. In the example of FIG. 5, the solvent discharge surface 872 is parallel to the conveying direction Ds and the Y direction. Further, the dispenser main body 871 has a plurality of discharge nozzles 873 opening at the solvent discharge surface 872. The plurality of discharge nozzles 873 are arranged at intervals in the Y direction. Then, the dispenser 87 discharges the solvent V from each of the discharge nozzles 873.

[0045] As shown in Figure 4, the dispenser 87 is supported by the housing 80 so as to face the cleaning sheet S upstream of the pressing surface 861 in the transport direction Ds. The dispenser 87 is located below the pressing position Hh (in other words, the mask M) and above the dispensing roller 81. In this example, the dispenser 87 is below the separation position Hl. However, the dispenser 87 may be positioned to protrude above the separation position Hl. The solvent discharge surface 872 of the dispenser 87 faces the surface S1 of the cleaning sheet S from the dispensing roller 81 toward the pressing surface 861. The solvent V discharged from each discharge nozzle 873 of the solvent discharge surface 872 is applied to the surface S1 of the cleaning sheet S upstream of the pressing surface 861 in the transport direction Ds.

[0046] Figure 6A is a flowchart showing a first example of a mask cleaning operation performed by the printing device, and Figure 6B is a schematic diagram showing the operations performed in the first example of the mask cleaning operation in Figure 6A. The flowchart in Figure 6A is executed by the control of the main control unit 10.

[0047] In step S101, the cleaning control unit 17 uses the head drive unit Mz to position the pressing surface 861 of the cleaning head 86 at the separated position Hl. In step S102, the cleaning control unit 17 starts dispensing solvent V from the dispenser 87. After a predetermined time has elapsed since the start of solvent V dispensing, the cleaning control unit 17 stops dispensing solvent V from the dispenser 87 (step S103). Throughout steps S101 to S103, the cleaning control unit 17 uses the sheet transport unit Ts to stop the cleaning sheet S from pressing on the pressing surface 861.

[0048] As shown in the "S103" column of Figure 6B, a coating area Ad is provided on the cleaning sheet S from the dispensing roller 81 to the pressing surface 861 in the transport direction Ds, and the solvent discharge surface 872 of the dispenser 87 discharges solvent V onto the surface S1 of the cleaning sheet S in the coating area Ad. Therefore, as steps S102 to S103 are executed, solvent V is applied to the surface S1 of the cleaning sheet S in the coating area Ad. As described above, since the cleaning sheet S has water absorption and water retention properties, the solvent V applied to the cleaning sheet S is absorbed and retained by the cleaning sheet S.

[0049] In step S104, the cleaning control unit 17 causes the sheet conveyance section Ts to convey the cleaning sheet S in the conveyance direction Ds. Accordingly, the solvent V applied to the cleaning sheet S is conveyed onto the pressing surface 861 of the cleaning head 86. As described above, the pressing surface 861 of the cleaning head 86 cleans the mask M by pressing the cleaning sheet S against the mask M. In other words, a cleaning region Ac for cleaning the mask M with the cleaning sheet S is provided on the pressing surface 861. That is, in step S104, the cleaning sheet S coated with the solvent V is supplied to the cleaning region Ac on the pressing surface 861.

[0050] In step S105, after the drive control unit 12 positions the cleaning unit 8 at the cleaning start position Ls (Fig. 1) by means of the X-axis drive section Mx, the cleaning control unit 17 raises the cleaning head 86 by means of the head drive section Mz to position the pressing surface 861 at the pressing position Hh. Accordingly, the surface S1 of the cleaning sheet S supported by the pressing surface 861 comes into contact with the upstream end of the mask M in the X direction (cleaning direction). At this time, the solvent V applied to the cleaning sheet S also comes into contact with the mask M.

[0051] At this time, for example, by turning off the brake 84, the cleaning sheet S can be fed in the conveyance direction Ds as the pressing surface 861 moves from the separated position Hl to the pressing position Hh. It is assumed that the feed amount of the cleaning sheet S corresponding to the movement of the pressing surface 861 is very small and negligible. Alternatively, the brake 84 may be kept turned on, and the cleaning sheet S may be expanded or contracted in accordance with the movement of the pressing surface 861.

[0052] In step S106, the drive control unit 12 causes the X-axis drive section Mx to move the cleaning unit 8 in the X direction. Accordingly, the cleaning sheet S coated with the solvent V moves in the X direction while being pressed against the mask M by the pressing surface 861. In this way, dirt (solder) adhering to the mask M can be dissolved by the solvent V and wiped off by the surface S1 of the cleaning sheet S.

[0053] In the embodiment described above, the dispenser 87 (cleaning solution application unit) applies solvent V (cleaning solution) to the cleaning sheet S in the application area Ad (steps S102 to S103), and then the sheet transport unit Ts transports the cleaning sheet S in the transport direction Ds (step S104), so that the cleaning sheet S coated with solvent V is transported to the cleaning area Ac on the pressing surface 861 (cleaning surface) of the cleaning head 86 (cleaning member). In this way, the solvent V is applied to the cleaning sheet S in an application area Ad, which is separate from the cleaning area Ac on the pressing surface 861 of the cleaning head 86, and then the solvent V applied to the cleaning sheet S is transported to the cleaning area Ac. That is, the application area Ad where the solvent V is applied and the cleaning area Ac where the mask M is cleaned are separated. This makes it possible to easily position the dispenser 87 that applies solvent V in the application area Ad away from the cleaning area Ac (Figures 4 and 6B). Therefore, in a technology for cleaning a mask M while supporting a cleaning sheet S coated with solvent V on the pressing surface 861 of a cleaning head 86, the dispenser 87 that applies the solvent V to the cleaning sheet S can be freely positioned.

[0054] Furthermore, the cleaning head 86, the sheet transport unit Ts, and the dispenser 87 are unitized as a cleaning unit 8 and are movable in the X direction (cleaning direction). The main control unit 10 (control unit) cleans the mask M by moving the cleaning unit 8 in the X direction while bringing the cleaning sheet S coated with solvent V into contact with the mask M in the cleaning area Ac (steps S105 to S106). In this configuration, the dispenser 87 is always facing the cleaning sheet S in the application area Ad, and can quickly apply solvent V to the cleaning sheet S as needed. In other words, there is no need to move the cleaning unit 8 to, for example, a solvent application unit provided separately at a location away from the cleaning unit 8. Therefore, the application of solvent V can be completed quickly, and the mask M can be cleaned efficiently.

[0055] Furthermore, the dispenser 87 (cleaning solution application unit) is positioned lower than the mask M, and moves away from the mask M during cleaning. With this configuration, interference between the dispenser 87 mounted on the cleaning unit 8 and the mask M is prevented, while the mask M can be cleaned by the cleaning sheet S supported by the cleaning head 86 mounted on the cleaning unit 8.

[0056] Furthermore, the cleaning sheet S has a surface S1 (contact surface) and a back surface S2 (non-contact surface) opposite to the surface S1, with the surface S1 contacting the mask M. The dispenser 87 applies the cleaning solution to the surface S1 of the two surfaces S1 and back surface S2. In other words, the dispenser 87 is mounted on the cleaning unit 8, and the cleaning unit 8 applies the solvent V to the surface S1 of the cleaning sheet S used for cleaning the mask M using the dispenser 87. This configuration is possible because an application area Ad is provided separately from the cleaning area Ac. In other words, if the solvent V were to be applied to the cleaning sheet S in the cleaning area Ac, the mask M would be located on the surface S1 side of the cleaning sheet S, making it impossible to place the dispenser 87. Therefore, it is necessary to configure the system so that the solvent V can be applied by the dispenser 87 from the back surface S2 side of the cleaning sheet S. However, when using a thick cleaning sheet S, it is difficult to absorb the solvent V applied to the back surface S2 to the surface S1 and supply it properly to the mask M. In contrast, in this embodiment, by providing a coating area Ad separate from the cleaning area Ac, the solvent V can be applied to the surface S1 of the cleaning sheet S by a dispenser 87 mounted on the cleaning unit 8. As a result, regardless of the thickness of the cleaning sheet S, the mask M can be effectively cleaned while ensuring that the solvent V adheres sufficiently to the mask M using a variety of cleaning sheets S.

[0057] Figure 7A is a flowchart showing a second example of a mask cleaning operation performed by the printing device, and Figures 7B and 7C are schematic diagrams showing the operations performed in the second example of the mask cleaning operation in Figure 7A. The flowchart in Figure 7A is executed by the control of the main control unit 10. In the following, we will mainly explain the differences from the first example described above, and common parts with the first example will be denoted by corresponding reference numerals and their explanations will be omitted as appropriate. It goes without saying that by having common parts with the first example, the same effects as the first example will be achieved. This point is also true for the other embodiments shown below.

[0058] In steps S201 to S203, the same operations as in steps S101 to S103 described above are performed. As a result, solvent V is applied to the surface S1 of the cleaning sheet S in the application area Ad. In step S204, the cleaning control unit 17 determines whether the number of times solvent V has been applied to the cleaning sheet S has reached a predetermined number of times. Here, the predetermined number of times is two or more, and in this example it is two times.

[0059] If the number of times the solvent V is applied to the cleaning sheet S is less than a predetermined number of times (if the answer is "NO" in step S204), the cleaning control unit 17 uses the winding roller 82 to transport the cleaning sheet S in the transport direction Ds for a predetermined intermittent transport distance (step S205). Here, the intermittent transport distance is, for example, less than or equal to the width of the application area Ad in the transport direction Ds, and in this example, equal to the width of the application area Ad. As a result, at least a portion (in this example, all) of the solvent V applied to the cleaning sheet S moves downstream of the application area Ad in the transport direction Ds.

[0060] Then, steps S202 to S203 are executed again. This applies solvent V to the surface S1 of the cleaning sheet S in the coating area Ad. As a result, the solvent V applied to the cleaning sheet S in the previous (first) application and the solvent V applied to the cleaning sheet S in the current (second) application are connected in the transport direction Ds.

[0061] When the number of times solvent V has been applied to the cleaning sheet S reaches a predetermined number (if "YES" is answered in step S204), the cleaning control unit 17 transports the cleaning sheet S in the transport direction Ds using the winding roller 82. This supplies the solvent V applied to the cleaning sheet S onto the pressing surface 861 of the cleaning head 86. In other words, the cleaning sheet S coated with solvent V is supplied to the cleaning area Ac on the pressing surface 861.

[0062] In step S207, similar to step S105 above, the drive control unit 12 positions the cleaning unit 8 to the cleaning start position Ls (Figure 1) using the X-axis drive unit Mx, and then the cleaning control unit 17 raises the cleaning head 86 using the head drive unit Mz to position the pressing surface 861 to the pressing position Hh. In step S208, similar to step S106 above, the drive control unit 12 moves the cleaning unit 8 in the X direction using the X-axis drive unit Mx. As a result, the mask M is cleaned.

[0063] In the embodiment described above, the main control unit 10 (control unit) applies solvent V to the cleaning sheet S in the coating area Ad multiple times at predetermined time intervals (the time interval between executing steps S202 to S203 and re-executing them) (steps S202 to S204). During this time interval, the cleaning sheet S is moved intermittently by a predetermined distance in the transport direction Ds. With this configuration, solvent V can be applied to the cleaning sheet S over a wide area in the transport direction Ds.

[0064] Figure 8A is a schematic perspective view showing an example of a suction unit that a printing device may have. In other words, the printing device 1 described above can be provided with the suction unit 9 shown in Figure 8A for the cleaning unit 8. In the example shown in Figure 8A, a plurality of suction holes 862 are opened on the pressing surface 861 of the cleaning head 86.

[0065] In contrast, the printing apparatus 1 includes a suction unit 9 that sucks air from each of the suction holes 862 of the cleaning head 86. The suction unit 9 includes a suction pump 91 and a flexible pipe 92 that connects the suction pump 91 to the cleaning head 86. The pipe 92 connects each of the multiple suction holes 862 to the suction pump 91. The suction pump 91 sucks air from each of the multiple suction holes 862 via the pipe 92. The suction unit 9 also includes a pressure gauge 93 that detects the pressure inside the pipe 92.

[0066] The main control unit 10, for example, in steps S104 and S206, transports the solvent V applied to the cleaning sheet S to the cleaning area Ac on the pressing surface 861, and then starts suction from the suction holes 862 using the suction pump 91. After starting suction from the suction holes 862, the main control unit 10 raises the pressing surface 861 of the cleaning unit 8, located at the cleaning start position Ls, from the separated position Hl to the pressing position Hh, bringing the cleaning sheet S, supported by the pressing surface 861, into contact with the mask M in the cleaning area Ac. By sliding the cleaning sheet S, which is pressed by the pressing surface 861 while suction is being applied to the suction holes 862, against the mask M in this way, the mask M can be cleaned efficiently.

[0067] Furthermore, the main control unit 10 can perform a cleaning preparation success / failure determination before the suction of the suction hole 862 by the suction pump 91 begins (Figure 8B). Figure 8B is a flowchart showing an example of a cleaning preparation success / failure determination that can be performed using the suction unit of Figure 8A. The flowchart in Figure 8B is executed under the control of the main control unit 10. In this cleaning preparation success / failure determination, the main control unit 10 determines whether the cleaning preparation, which involves applying solvent V to the cleaning sheet S and transporting it to the cleaning area Ac, is successful. Here, the cleaning preparation corresponds to the operations in steps S101 to S104 or steps S201 to S206.

[0068] In other words, if the discharge rate of solvent V or the transport distance of the cleaning sheet S is inappropriate, it is conceivable that the cleaning preparation may fail. To address this, the success or failure of the cleaning preparation is determined before starting to wipe the mask M with the cleaning sheet S (steps S105-S106, steps S207-S208). Note that the manner in which solvent V is present on the pressing surface 861 differs between successful and unsuccessful cleaning preparations, resulting in a difference in the negative pressure generated when the suction hole 862 of the pressing surface 861 is sucked. Therefore, in the flowchart of Figure 8B, the success or failure of the cleaning preparation is determined based on this negative pressure.

[0069] In step S301, the main control unit 10 determines whether the pressing surface 861 is located at the separated position Hl. If the pressing surface 861 is located at the separated position Hl (if the answer in step S301 is "YES"), the process proceeds to step S303. If the pressing surface 861 is not located at the separated position Hl (if the answer in step S301 is "NO"), the pressing surface 861 is moved to the separated position Hl (step S302), and then the process proceeds to step S303.

[0070] In step S303, the main control unit 10 starts suction from the suction port 862 using the suction pump 91. In step S304, the main control unit 10 checks the negative pressure (measured negative pressure Pm) detected by the pressure gauge 93. That is, it checks the negative pressure (measured negative pressure Pm) generated in the suction port 862 when the cleaning sheet S, which is separated from the mask M, is sucked in by the suction pump 91 through the suction port 862. The main control unit 10 then determines whether the measured negative pressure Pm is equal to or greater than the first threshold Pt1 (step S305). The first threshold Pt1 is the negative pressure that serves as the criterion for determining the success or failure of the cleaning preparation. Here, negative pressure is defined as a pressure lower than atmospheric pressure, and negative pressure is given by the absolute value of the difference from atmospheric pressure.

[0071] If the measured negative pressure Pm is greater than or equal to the first threshold Pt1 (if "YES" is answered in step S305), the main control unit 10 performs wiping of the mask M with the cleaning sheet S in step S306 (corresponding to steps S105-S106 and S207-S208 described above). That is, the cleaning unit 8 is moved in the X direction from the cleaning start position Ls while positioning the pressing surface 861 supporting the cleaning sheet S at the pressing position Hh. If the measured negative pressure Pm is less than the first threshold Pt1 (if "NO" is answered in step S305), the main control unit 10 performs the cleaning preparation condition optimization described below (step S307).

[0072] Figure 9 is a flowchart showing the first example of optimizing cleaning preparation conditions. The flowchart in Figure 9 is executed by the control of the main control unit 10. In step S401, the main control unit 10 increases the set value of the amount of solvent V (discharge amount) discharged from the dispenser 87 onto the cleaning sheet S in the coating area Ad by a predetermined amount. In step S402, the main control unit 10 determines whether the set value of the discharge amount is less than a predetermined upper limit. If the set value of the discharge amount is greater than or equal to the upper limit (if "NO" is found in step S402), the main control unit 10 determines that an error stop has occurred and that the cleaning of the mask M cannot be performed, and notifies the operator of the occurrence of the error stop via the display unit 14 (step S408).

[0073] If the set value of the discharge amount is less than the upper limit (if "YES" is selected in step S402), the main control unit 10 discharges the amount of solvent V indicated by the set value from the dispenser 87 onto the cleaning sheet S in the coating area Ad (step S403). Subsequently, the main control unit 10 transports the cleaning sheet S in the transport direction Ds to transport the solvent V applied to the cleaning sheet S to the cleaning area Ac on the pressing surface 861. Then, the main control unit 10 confirms the negative pressure (measured negative pressure Pm) indicated by the pressure gauge 93 (step S405).

[0074] In step S406, the main control unit 10 determines whether the measured negative pressure Pm indicated by the pressure gauge 93 is within the range (reference range) of being less than the first threshold Pt1 and greater than or equal to the second threshold Pt2. Here, the second threshold Pt2 corresponds to a negative pressure smaller than the first threshold Pt1 (in other words, a higher atmospheric pressure).

[0075] If the measured negative pressure Pm is within the reference range of the first threshold Pt1 to the second threshold Pt2 (if "YES" is answered in step S406), the main control unit 10 returns to step S401. In other words, steps S403 to S406 are repeated while gradually increasing the set value of the discharge amount (step S401) until the measured negative pressure Pm falls outside the reference range ("NO" is answered in step S406) or the set value of the discharge amount reaches the upper limit ("NO" is answered in step S402).

[0076] On the other hand, if the measured negative pressure Pm is outside the reference range of the first threshold Pt1 to the second threshold Pt2 (if "NO" is answered in step S406), the main control unit 10 determines whether the measured negative pressure Pm is less than the second threshold Pt2 (step S407). If the measured negative pressure Pm is less than the second threshold Pt2 (if "YES" is answered in step S407), the main control unit 10 notifies the operator of the occurrence of an error stop using the display unit 14 (step S408).

[0077] If the measured negative pressure Pm is not less than the second threshold Pt2 (in the case of "NO" in step S407), then the solvent V is discharged from the dispenser 87 at a discharge rate of a set value that has been gradually increased, resulting in a measured negative pressure Pm of or greater than the first threshold Pt1. Therefore, the main control unit 10 determines the condition (discharge condition) to discharge the solvent V at the discharge rate indicated by the set value (step S409). As a result, in the mask cleaning operations S102 to S103 or S202 to S203 that are performed thereafter, the solvent V is discharged at the discharge rate indicated by the determined discharge condition.

[0078] In the embodiment described above, a suction pump 91 (suction unit) is provided to suck up the suction hole 862 that opens on the pressing surface 861 (cleaning surface). The main control unit 10 (control unit) performs a success or failure check (steps S303 to S305) to confirm whether the cleaning preparation, in which the cleaning sheet S is coated with solvent V and transported to the cleaning area Ac, is successful or not, based on the negative pressure (measured negative pressure Pm) at the suction hole 862 when the suction pump 91 sucks up the suction hole 862. With this configuration, the success or failure of the cleaning preparation can be confirmed.

[0079] Furthermore, if the main control unit 10 confirms a failure in the cleaning preparation ("NO" in step S305), it changes the amount of solvent V applied to the cleaning sheet S in the application area Ad (step S307). With this configuration, it becomes possible to successfully complete the cleaning preparation by changing the amount of solvent V applied (step S409).

[0080] Furthermore, the main control unit 10 determines the amount of cleaning solution to be applied (step S409) based on the result of determining whether or not the cleaning preparation will be successful by changing the amount of cleaning solution applied (steps S401 to S407). With this configuration, the amount of solvent V to be applied to the cleaning sheet S in the application area Ad can be appropriately determined, thereby ensuring the cleaning preparation is successful.

[0081] Furthermore, a display unit 14 (error notification unit) is provided to notify the operator of errors. If the main control unit 10 determines that the cleaning preparation will not be successful even if the amount of solvent V applied is changed (if the answer is "NO" in step S402 / if the answer is "NO" in step S406 and "YES" in step S407), it causes the display unit 14 to notify the operator of the error (step S408). With this configuration, the error notification can prompt the operator to perform the necessary maintenance work.

[0082] Figure 10 is a flowchart showing a second example of optimizing cleaning preparation conditions. The flowchart in Figure 10 is executed by the control of the main control unit 10. The difference from the first example of optimizing cleaning preparation conditions in Figure 9 is that the cleaning sheet S is rewound between step S402 and step S403 (step S411).

[0083] In other words, the sheet transport section Ts of the cleaning unit 8, which implements the second example of optimizing cleaning preparation conditions, has a rewind motor instead of a brake 84. The cleaning control unit 17 rotates the feed roller 81 with the rewind motor and winds up the cleaning sheet S with the feed roller 81, thereby transporting the cleaning sheet S in the reverse transport direction (opposite direction of the transport direction Ds) from the winding roller 82 to the feed roller 81. In step S411, the sheet transport section Ts transports the cleaning sheet S in the reverse transport direction for a predetermined rewind distance. This rewind distance corresponds to the distance the cleaning sheet S was transported in step S104 or step S206 in order to transport the solvent V applied to the cleaning sheet S to the cleaning area Ac on the pressing surface 861 during cleaning preparation.

[0084] Incidentally, the main control unit 10 may also set whether or not to perform rewinding in response to the operator's operation on the input unit 15. In other words, if rewinding is not set, the main control unit 10 skips step S411 and executes step S403, and if rewinding is set, it executes step S411 and then step S403.

[0085] Figures 11A and 11B are flowcharts showing a third example of optimizing cleaning preparation conditions. The flowcharts in Figures 11A and 11B are executed by the control of the main control unit 10. As shown in Figure 11A, in step S501, the main control unit 10 increases the set value of the transport distance of the cleaning sheet S (sheet transport distance) by a predetermined distance. Here, the transport distance of the cleaning sheet S is the transport distance over which the cleaning sheet S is transported in step S104 or step S206 to transport the solvent V applied to the cleaning sheet S to the cleaning area Ac on the pressing surface 861. In step S502, the main control unit 10 determines whether the set value of the transport distance is less than a predetermined upper limit. If the set value of the transport distance is greater than or equal to the upper limit (if "NO" is found in step S502), the process proceeds to step S510 (Figure 11B).

[0086] If the set value for the transport distance is less than the upper limit (if "YES" is selected in step S502), the main control unit 10 dispenses the solvent V from the dispenser 87 onto the cleaning sheet S in the coating area Ad (step S503). Subsequently, the main control unit 10 transports the cleaning sheet S in the transport direction Ds by the transport distance indicated by the set value, and transports the solvent V applied to the cleaning sheet S to the cleaning area Ac on the pressing surface 861 (step S504). Then, the main control unit 10 checks the negative pressure (measured negative pressure Pm) indicated by the pressure gauge 93 (step S505).

[0087] In step S506, the main control unit 10 determines whether the measured negative pressure Pm indicated by the pressure gauge 93 is within the range (reference range) of being less than the first threshold Pt1 and greater than or equal to the second threshold Pt2. Here, the second threshold Pt2 corresponds to a negative pressure smaller than the first threshold Pt1 (in other words, a higher atmospheric pressure).

[0088] If the measured negative pressure Pm is within the reference range of the first threshold Pt1 to the second threshold Pt2 (if "YES" is answered in step S506), the main control unit 10 returns to step S501. In other words, steps S503 to S506 are repeated while gradually increasing the set value of the transport distance (step S501) until the measured negative pressure Pm falls outside the reference range ("NO" is answered in step S506) or the set value of the transport distance reaches the upper limit ("NO" is answered in step S502).

[0089] On the other hand, if the measured negative pressure Pm is outside the reference range of the first threshold Pt1 to the second threshold Pt2 (if "NO" is answered in step S506), the main control unit 10 determines whether the measured negative pressure Pm is less than the second threshold Pt2 (step S507). If the measured negative pressure Pm is less than the second threshold Pt2 (if "YES" is answered in step S507), the process proceeds to step S510 (Figure 11B).

[0090] If the measured negative pressure Pm is not less than the second threshold Pt2 (if the answer is "NO" in step S507), it means that the cleaning sheet S has been transported at a transport distance of a set value that has been increased in stages, resulting in a measured negative pressure Pm that is equal to or greater than the first threshold Pt1. Therefore, the main control unit 10 determines a condition (transportation condition) to transport the cleaning sheet S at the transport distance indicated by the set value (step S509). As a result, in step S104 or step S206 of the mask cleaning operation that is performed thereafter, the cleaning sheet S is transported in the transport direction Ds by the transport distance indicated by the determined transport condition.

[0091] As shown in Figure 11B, in step S510, the main control unit 10 resets the set value for the sheet transport distance. This returns the set value to the value before it was increased in step S501 in Figure 11A. In step S511, the main control unit 10 decreases the set value for the transport distance of the cleaning sheet S (sheet transport distance) by a predetermined distance. In step S512, the main control unit 10 determines whether the set value for the transport distance is greater than a predetermined lower limit. If the set value for the transport distance is less than or equal to the lower limit (if the result is "NO" in step S512), the main control unit 10 determines that an error stop has occurred and that the cleaning of the mask M cannot be performed, and notifies the operator of the error stop via the display unit 14 (step S518).

[0092] If the set value for the transport distance is greater than the lower limit (if "YES" is selected in step S512), the main control unit 10 dispenses the solvent V from the dispenser 87 onto the cleaning sheet S in the coating area Ad (step S513). Subsequently, the main control unit 10 transports the cleaning sheet S in the transport direction Ds by the transport distance indicated by the set value, and transports the solvent V applied to the cleaning sheet S to the cleaning area Ac on the pressing surface 861 (step S514). Then, the main control unit 10 checks the negative pressure (measured negative pressure Pm) indicated by the pressure gauge 93 (step S515).

[0093] In step S516, the main control unit 10 determines whether the measured negative pressure Pm indicated by the pressure gauge 93 is within the range (reference range) of being less than the first threshold Pt1 and greater than or equal to the second threshold Pt2. Here, the second threshold Pt2 corresponds to a negative pressure smaller than the first threshold Pt1 (in other words, a higher atmospheric pressure).

[0094] If the measured negative pressure Pm is within the reference range of the first threshold Pt1 to the second threshold Pt2 (if "YES" is answered in step S516), the main control unit 10 returns to step S511. In other words, steps S513 to S516 are repeated while gradually decreasing the set value of the transport distance (step S511) until the measured negative pressure Pm falls outside the reference range ("NO" is answered in step S516) or the set value of the transport distance reaches the lower limit (until "NO" is answered in step S512).

[0095] On the other hand, if the measured negative pressure Pm is outside the reference range of the first threshold Pt1 to the second threshold Pt2 (if "NO" is answered in step S516), the main control unit 10 determines whether the measured negative pressure Pm is less than the second threshold Pt2 (step S517). If the measured negative pressure Pm is less than the second threshold Pt2 (if "YES" is answered in step S517), the main control unit 10 determines that an error stop has occurred that prevents the cleaning of the mask M, and notifies the operator of the error stop via the display unit 14 (step S518).

[0096] If the measured negative pressure Pm is not less than the second threshold Pt2 (if the answer is "NO" in step S517), it means that the cleaning sheet S was transported at a transport distance of a gradually decreasing set value, resulting in a measured negative pressure Pm of or greater than the first threshold Pt1. Therefore, the main control unit 10 determines a condition (transportation condition) to transport the cleaning sheet S at the transport distance indicated by the set value (step S519). As a result, in step S104 or step S206 of the mask cleaning operation that is executed thereafter, the cleaning sheet S is transported in the transport direction Ds by the transport distance indicated by the determined transport condition.

[0097] In this example, the flow that increases the transport distance and the flow that decreases the transport distance are executed in this order. However, the execution order of these flows can also be reversed.

[0098] In the embodiment described above, if the main control unit 10 confirms a failure in cleaning preparation ("NO" in step S305), it changes the transport distance (transport amount) of the cleaning sheet S to transport the solvent V applied to the cleaning sheet S to the cleaning area Ac (step S307). With this configuration, it is possible to successfully complete the cleaning preparation by changing the transport distance of the cleaning sheet S (steps S509, S519).

[0099] Furthermore, the main control unit 10 determines the transport distance (steps S509, S519) based on the result of determining whether the cleaning preparation will be successful by changing the transport distance of the cleaning sheet S (steps S501 to S507, S511 to S517). With this configuration, the distance over which the cleaning sheet S is transported can be appropriately determined, and the cleaning preparation can be successfully completed.

[0100] Furthermore, a display unit 14 (error notification unit) is provided to notify the operator of errors. If the main control unit 10 determines that cleaning preparation will not be successful even if the transport distance of the cleaning sheet S is changed, it causes the display unit 14 to notify the operator of the error (step S518). With this configuration, the operator can be prompted to perform necessary maintenance work by notifying them of the error.

[0101] Figures 12A and 12B are flowcharts of the fourth example of optimizing cleaning preparation conditions. The flowcharts in Figures 12A and 12B are executed by the control of the main control unit 10. The difference from the third example of optimizing cleaning preparation conditions in Figures 11A and 11B is that the solvent V is not discharged instead of rewinding the cleaning sheet S. In other words, step S521 (Figure 12A) is executed instead of step S503 (Figure 11A), and step S522 (Figure 12B) is executed instead of step S513 (Figure 11B).

[0102] In the third example of this optimization of cleaning preparation conditions, the sheet transport section Ts of the cleaning unit 8 has a rewind motor instead of a brake 84. In other words, the cleaning control unit 17 rotates the feed roller 81 with the rewind motor and winds up the cleaning sheet S with the feed roller 81, thereby transporting the cleaning sheet S in the reverse transport direction (opposite direction of the transport direction Ds) from the winding roller 82 to the feed roller 81.

[0103] In step S521 (Figure 12A), the sheet transport unit Ts transports the cleaning sheet S in the reverse transport direction by a predetermined rewind distance. This rewind distance corresponds to the transport distance of the cleaning sheet S immediately preceding the transport to transport the solvent V applied to the cleaning sheet S to the cleaning area Ac on the pressing surface 861. In other words, the rewind distance corresponds to the distance indicated by the set value before it is increased by a predetermined distance in step S501.

[0104] In step S522 (Figure 12B), the sheet transport unit Ts transports the cleaning sheet S in the reverse transport direction by a predetermined rewind distance. This rewind distance corresponds to the transport distance of the cleaning sheet S immediately preceding the transport to transport the solvent V applied to the cleaning sheet S to the cleaning area Ac on the pressing surface 861. In other words, the rewind distance corresponds to the distance indicated by the set value before it is reduced by a predetermined distance in step S511.

[0105] In the above embodiment, the mask M corresponds to an example of the "mask" of the present invention, the substrate B corresponds to an example of the "substrate" of the present invention, the printing apparatus 1 corresponds to an example of the "printing apparatus" of the present invention, the pressing surface 861 corresponds to an example of the "cleaning surface" of the present invention, the coating area Ad corresponds to an example of the "cleaning area" of the present invention, the cleaning sheet S corresponds to an example of the "cleaning sheet" of the present invention, the X direction corresponds to an example of the "cleaning direction" of the present invention, the cleaning head 86 corresponds to an example of the "cleaning member" of the present invention, the transport direction Ds corresponds to an example of the "transport direction" of the present invention, and the sheet transport section Ts corresponds to the present invention This corresponds to an example of the "sheet transport unit" of the present invention, solvent V corresponds to an example of the "cleaning liquid" of the present invention, dispenser 87 corresponds to an example of the "cleaning liquid application unit" of the present invention, main control unit 10 corresponds to an example of the "control unit" of the present invention, cleaning unit 8 corresponds to an example of the "cleaning unit" of the present invention, surface S1 corresponds to an example of the "contact surface" of the present invention, back surface S2 corresponds to an example of the "non-contact surface" of the present invention, suction hole 862 corresponds to an example of the "suction hole" of the present invention, suction unit 9 corresponds to an example of the "suction unit" of the present invention, and display unit 14 corresponds to an example of the "error notification unit" of the present invention.

[0106] It should be noted that the present invention is not limited to the embodiments described above, and various modifications can be made to those described above without departing from the spirit of the invention. For example, while the dispenser 87 is applying solvent V to the application area Ad in steps S102 to S103, the cleaning sheet S may be conveyed in the conveying direction Ds by the sheet conveying unit Ts. In other words, in this modified example, the main control unit 10 (control unit) applies solvent V to the cleaning sheet S in the application area Ad while conveying the cleaning sheet S in the conveying direction Ds. This makes it possible to apply solvent V to the cleaning sheet S over a wide area in the conveying direction Ds.

[0107] Furthermore, the range of presence Ev of the solvent V applied to the cleaning sheet S may be biased within the cleaning area Ac (Figures 13A and 13B). Figures 13A and 13B schematically show variations in the range of presence of the solvent applied to the cleaning sheet within the cleaning area. In the example of Figure 13A, the range of presence Ev of the solvent V in the cleaning area Ac is biased downstream in the transport direction Ds and downstream in the X direction (cleaning direction). In the example of Figure 13B, the range of presence Ev of the solvent V in the cleaning area Ac is biased upstream in the transport direction Ds and upstream in the X direction (cleaning direction).

[0108] In other words, the main control unit 10 (control unit) transports the solvent V (cleaning liquid) applied to the cleaning sheet S to the cleaning area Ac so that the range of presence Ev of the solvent V applied to the cleaning sheet S is concentrated in the cleaning area Ac. To put it another way, the main control unit 10 concentrates the range of presence Ev of the solvent V in the cleaning area Ac by adjusting the transport distance in the transport direction Ds of the cleaning sheet S. With this configuration, it is possible to reduce the amount of solvent V consumed by applying the solvent V only to the parts of the mask M that are effective for cleaning.

[0109] In particular, when cleaning the mask M by moving the cleaning head 86 in the X direction (cleaning direction), the portion of the cleaning sheet S in the cleaning area Ac supported by the pressing surface 861 of the cleaning head 86 that is downstream in the X direction tends to make firmer contact with the mask M than the portion that is upstream in the X direction. Therefore, as shown in Figure 13A, it is preferable to bias the range Ev where the solvent V exists in the cleaning area Ac towards the downstream side in the X direction (cleaning direction).

[0110] Furthermore, it is not essential to mount the dispenser 87 on the cleaning unit 8. Figures 14A and 14B schematically show modified configurations of the dispenser. In these examples, the dispenser 87 is separate from the cleaning unit 8 and is located adjacent to the mask M. Therefore, the positional relationship between the dispenser 87 and the mask M is fixed, and the cleaning unit 8 moves independently of the dispenser 87 in the X direction.

[0111] In the printing apparatus 1, when preparing for cleaning, the cleaning unit 8 moves to the underside of the dispenser 87, so that the coating area Ad faces the dispenser 87 from below (Figure 14A). In this state, the dispenser 87 applies solvent V to the coating area Ad. Subsequently, the cleaning unit 8 moves to the cleaning start position Ls (Figure 14B), and positions the pressing surface 861 at the pressing position Hh. During the period from when the dispenser 87 applies solvent V to the coating area Ad until the pressing surface 861 is at the pressing position Hh, the sheet transport unit Ts transports the solvent V to the coating area Ad.

[0112] Furthermore, the arrangement of the dispenser 87 can be changed as appropriate. For example, the orientation of the dispenser 87 can be changed as appropriate, and the dispenser 87 may be arranged horizontally. Alternatively, the dispenser 87 may be placed on the back surface S2 side of the cleaning sheet S, and the solvent V may be discharged from the dispenser 87 onto the back surface S2 of the cleaning sheet S. Moreover, the specific configuration of the dispenser 87 can also be changed as appropriate. In other words, various configurations that allow solvent V to be applied to the cleaning sheet S can be used as the dispenser 87.

[0113] 1…Printing device 10…Main control unit 14…Display unit 8…Cleaning unit 86…Cleaning head 861…Pressing surface 862…Suction hole 87…Dispenser 9…Suction section Ad…Coating area B…Substrate Ds…Transport direction M…Mask S…Cleaning sheet S1…Front surface S2…Back surface Ts…Sheet transport section V…Solvent

Claims

1. A printing apparatus for printing solder onto a substrate via a mask, comprising: a cleaning member having a cleaning surface and cleaning the mask by moving a cleaning sheet supplied to a cleaning area on the cleaning surface in a cleaning direction along the mask while bringing the sheet into contact with the mask; a sheet transport unit transporting the cleaning sheet in a predetermined transport direction to supply the cleaning sheet to the cleaning surface; a cleaning liquid application unit applying a cleaning liquid to the cleaning sheet; and a control unit controlling the cleaning liquid application unit to apply the cleaning liquid to the cleaning sheet in an application area upstream of the cleaning area in the transport direction, and then controlling the sheet transport unit to transport the cleaning sheet in the transport direction to transport the cleaning liquid applied to the cleaning sheet to the cleaning area.

2. The printing apparatus according to claim 1, wherein the cleaning member, the sheet transport unit, and the cleaning liquid application unit are unitized as a cleaning unit and are movable in the cleaning direction, and the control unit cleans the mask by moving the cleaning unit in the cleaning direction while bringing the cleaning sheet to which the cleaning liquid has been applied into contact with the mask in the cleaning area.

3. The printing apparatus according to claim 2, wherein the cleaning solution application section is located at a lower position than the mask and is separated from the mask while the mask is being cleaned.

4. The printing apparatus according to claim 2 or 3, wherein the cleaning sheet has a contact surface and a non-contact surface opposite to the contact surface, the contact surface of which is in contact with the mask, and the cleaning solution application unit applies the cleaning solution to the contact surface of which is in contact with the mask.

5. The printing apparatus according to any one of claims 1 to 4, wherein the control unit performs the application of cleaning liquid to the cleaning sheet in the application area multiple times at predetermined time intervals, and moves the cleaning sheet by a predetermined distance in the transport direction during the time intervals.

6. The printing apparatus according to any one of claims 1 to 4, wherein the control unit applies the cleaning solution to the cleaning sheet in the coating area while conveying the cleaning sheet in the conveying direction.

7. The printing apparatus according to any one of claims 1 to 6, wherein the control unit transports the cleaning liquid applied to the cleaning sheet to the cleaning area such that the area where the cleaning liquid applied to the cleaning sheet is concentrated in the cleaning area.

8. The printing apparatus according to claim 7, wherein the range of presence is biased toward the downstream side in the cleaning direction within the cleaning area.

9. The printing apparatus according to any one of claims 1 to 8, further comprising a suction unit that sucks a suction hole opening in the cleaning surface, wherein the control unit performs a success or failure check to confirm whether the cleaning preparation, which involves applying a cleaning solution to the cleaning sheet and transporting it to the cleaning area, is successful, based on the pressure of the suction hole when the suction unit sucks the suction hole.

10. The printing apparatus according to claim 9, wherein the control unit, upon confirming a failure in the cleaning preparation, changes the amount of cleaning solution applied to the cleaning sheet in the application area.

11. The printing apparatus according to claim 10, wherein the control unit determines the amount of cleaning solution to be applied based on the result of determining whether or not the cleaning preparation is successful by changing the amount of cleaning solution applied.

12. The printing apparatus according to claim 11, further comprising an error notification unit for notifying an operator of an error, wherein the control unit causes the error notification unit to notify an error if it determines that the cleaning preparation will not be successful even if the amount of cleaning solution applied is changed.

13. The printing apparatus according to claim 9, wherein the control unit, upon confirming a failure in the cleaning preparation, changes the amount of the cleaning sheet to be transported for transporting the cleaning solution applied to the cleaning sheet to the cleaning area.

14. The printing apparatus according to claim 13, wherein the control unit determines the transport amount based on the result of determining whether or not the cleaning preparation is successful by changing the transport amount.

15. The printing apparatus according to claim 14, further comprising an error notification unit for notifying an operator of an error, wherein the control unit causes the error notification unit to notify an error if it determines that the cleaning preparation will not be successful even if the amount of the cleaning sheet to be transported is changed.

16. A mask cleaning method for cleaning a mask used to print solder onto a substrate via a mask, comprising: a step of applying a cleaning solution to a cleaning sheet in an application area of ​​a cleaning solution application unit; a step of conveying the cleaning sheet coated with the cleaning solution to a cleaning area on the cleaning surface of a cleaning member by conveying the cleaning sheet in a conveying direction of a sheet conveying unit; and a step of cleaning the mask by moving the cleaning member in a cleaning direction along the mask while bringing the cleaning sheet supplied to the cleaning area into contact with the mask.

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