Screen printing apparatus and screen printing method

Abstract

The objective is to provide a screen printing apparatus and screen printing method that can perform mask cleaning with appropriate power consumption. [Solution] Paste is printed onto the substrate through a printing opening provided in the mask (Step ST2), and the mask is cleaned by sucking up the paste adhering to the mask during the printing process along with the air using an electrically driven suction unit (Step ST3). Then, the cleanliness of the mask after the paste has been removed is inspected (Step ST4), and based on the results of the inspection, it is determined that the mask is clean (Step ST5). If it is determined that the mask is clean, the suction force of the suction unit is reduced and mask cleaning is performed on the next mask, and if it is determined in the determination step that the mask is not clean, mask cleaning is repeated with the suction force of the suction unit increased.

Description

Technical Field

[0001] The present disclosure relates to a screen printing apparatus and a screen printing method for printing paste onto a substrate through a mask provided with printing apertures.

Background Art

[0002] Conventionally, a screen printing apparatus is known that prints paste onto a substrate by bringing a mask provided with printing apertures into contact with the substrate and filling the apertures with paste from the upper surface side of the mask. In a screen printing apparatus, when performing plate separation to separate the substrate from the mask after printing paste onto the substrate, a part of the paste in the printing apertures wraps around to the lower surface of the mask and the paste adheres to the lower surface of the mask. If the next substrate is brought into contact with the mask as it is, the substrate will be soiled by the paste. For this reason, the screen printing apparatus includes cleaning means called a mask cleaner, and the mask cleaner can remove the paste adhering to the mask before bringing the next substrate into contact with the mask (for example, Patent Document 1 below).

[0003] The mask cleaner usually includes a paper member that slides on the lower surface of the mask to scrape off the paste adhering to the lower surface of the mask, and a suction portion that sucks the paste in the printing apertures. The suction portion has a function of sucking the paste together with air by the negative pressure generated by the operation of an electrically driven motor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When using the suction unit to remove paste as described above, it is desirable to use the maximum suction force the suction unit can exert to remove air (and therefore paste) in order to prevent paste from remaining on the mask due to insufficient suction. However, in some cases, the paste adhering to the mask can be sufficiently removed without using the maximum suction force of the suction unit. In this case, the suction force is excessive, resulting in wasted power. When printing paste onto multiple substrates continuously using the same mask, the state of paste adhesion on the mask is usually almost the same each time. Therefore, if the suction force is excessive during the initial cleaning, the excessive suction force will continue thereafter, resulting in significant power waste.

[0006] Therefore, the purpose of this disclosure is to provide a screen printing apparatus and a screen printing method that can reliably perform mask cleaning while suppressing the wasteful consumption of electricity. [Means for solving the problem]

[0007] The screen printing apparatus of this disclosure comprises: a mask provided with a printing opening; a printing unit for printing paste onto a substrate through the printing opening of the mask; a cleaning means for cleaning the mask by using an electrically driven suction unit to suck up paste adhering to the mask after printing along with the air; an inspection unit for inspecting the clean state of the mask after the paste has been removed; a determination unit for determining whether the clean state of the mask is good or bad based on the results of the inspection by the inspection unit; and a cleaning control unit that, if the determination unit determines that the clean state of the mask is good, performs the next cleaning of the mask with the suction force of the suction unit reduced.

[0008] The screen printing method of this disclosure comprises: a printing step of printing paste onto a substrate through a printing opening provided in a mask; a mask cleaning step of cleaning the mask by using an electrically driven suction unit to suck up the paste adhering to the mask in the printing step along with the air; an inspection step of inspecting the clean state of the mask after the paste has been removed; and a determination step of determining whether the clean state of the mask is good based on the results of the inspection in the inspection step. If the determination step determines that the clean state of the mask is good, the mask cleaning step is performed on the next mask with the suction force of the suction unit reduced. If the determination step determines that the clean state of the mask is not good, the mask cleaning step is re-executed with the suction force of the suction unit increased. [Effects of the Invention]

[0009] According to this disclosure, mask cleaning can be performed reliably while minimizing the wasteful consumption of electricity. [Brief explanation of the drawing]

[0010] [Figure 1] This is a diagram showing the main components of a screen printing apparatus in one embodiment of the present disclosure. [Figure 2] (a)(b)(c)(d) These figures illustrate the printing operation of a screen printing apparatus in one embodiment of the present disclosure. [Figure 3] This graph shows an example of the relationship between the drive frequency of the motor in a screen printing apparatus according to one embodiment of the present disclosure and the suction force generated in the suction nozzle. [Figure 4] This figure shows how paste adhering to a mask is removed by a mask cleaner provided in a screen printing apparatus according to one embodiment of the present disclosure. [Figure 5] This flowchart shows the flow of a screen printing operation performed by a screen printing apparatus in one embodiment of the present disclosure. [Figure 6]This figure shows how the state of a mask after the paste has been removed by a mask cleaner in a screen printing apparatus according to one embodiment of the present disclosure is being checked by a camera. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described below with reference to the drawings. Figure 1 shows a screen printing apparatus 10 in one embodiment of this disclosure. The screen printing apparatus 10 is an apparatus for printing paste Pst onto a substrate KB and comprises a substrate support 11, a mask 12, a squeegee 13, a camera 14, and a mask cleaner 15.

[0012] In Figure 1, the substrate support 11 is a member that supports the substrate KB on which paste Pst is printed, and supports the lower surface of the substrate KB so that the multiple electrodes DK placed on the substrate KB face upward. The substrate support 11 is connected to a substrate support movement mechanism 11M, which consists of, for example, an XYZ table. The substrate support 11 moves in the horizontal direction, the vertical direction, and the rotational direction around the vertical axis in response to the operation of the substrate support movement mechanism 11M.

[0013] The mask 12 is composed of a rectangular metal plate-shaped member that extends along a horizontal plane. The mask 12 is supported around its perimeter by a rectangular frame 12W. In the central region of the mask 12, there are multiple printed openings 12K arranged to correspond to multiple electrodes DK on the substrate KB. In addition to the printed openings 12K, the mask 12 is also provided with multiple mask-side marks 12M that are aligned with multiple substrate-side marks KM provided on the substrate KB (Figure 1).

[0014] In Figure 1, the squeegee 13 holds the blade 13B in an oblique position. The blade 13B consists of a spatula-shaped member extending perpendicular to the plane of the paper in Figure 1. The squeegee 13 is moved horizontally (arrow A shown in Figure 1) by a squeegee moving mechanism 13M, which consists of, for example, a ball screw mechanism.

[0015] Camera 14 has imaging fields above and below it, and images objects located above and below it. Camera 14 is moved horizontally (arrow B shown in Figure 1) within the region between the substrate support 11 and the mask 12 by a camera movement mechanism 14M, which consists of, for example, a ball screw mechanism. Each of the above parts of the screen printing apparatus 10 (substrate support movement mechanism 11M, squeegee movement mechanism 13M, and camera movement mechanism 14M) is controlled by a control device 16 (Figure 1) provided in the screen printing apparatus 10.

[0016] The control device 16 operates each part of the screen printing device 10 to perform a printing operation to print paste Pst onto the substrate KB. When performing the printing operation, the control device 16 first moves the camera 14 to the area between the substrate support part 11 and the mask 12, with the substrate support part 11 supporting the lower surface of the substrate KB and the mask 12 separated vertically. Then, it captures an image of the mask-side mark 12M located above the camera 14, and also captures an image of the substrate-side mark KM located below the camera 14 (Figure 2(a)).

[0017] When camera 14 captures images of the mask-side mark 12M and the substrate-side mark KM, it transmits the images and positional information obtained from the capture to the control device 16. Based on the information sent from camera 14, the control device 16 calculates the positional misalignment between substrate KB and mask 12 in a plan view. After calculating the positional misalignment between substrate KB and mask 12 in a plan view, the control device 16 moves camera 14 out of the area between substrate KB and mask 12 and moves substrate support 11 in the horizontal plane so that the calculated positional misalignment is canceled out. When the mask-side mark 12M and substrate-side mark KM are aligned in a plan view, the substrate support 11 is raised to bring substrate KB into contact with mask 12 (Figure 2(b)).

[0018] When the substrate KB contacts the mask 12, the electrode DK of the substrate KB and the printing aperture 12K of the mask 12 are in alignment. When the electrode DK and the printing aperture 12K are in alignment, the control device 16 moves the squeegee 13 by the squeegee movement mechanism 13M (arrow A shown in Fig. 2(c)), and scrapes the paste Pst supplied onto the mask 12 on the mask 12. As a result, the paste Pst is filled into the printing aperture 12K from the upper surface side of the mask 12, and the paste Pst is transferred to the electrode DK through the printing aperture 12K.

[0019] When the paste Pst is transferred to the electrode DK of the substrate KB, the control device 16 lowers the substrate support portion 11 by the substrate support portion movement mechanism 11M to separate the substrate KB from the mask 12 (plate separation) (Fig. 2(d)). As a result, the paste Pst is printed on the substrate KB.

[0020] Thus, in this embodiment, the squeegee 13 serves as a printing unit that prints the paste Pst on the substrate KB through the printing aperture 12K of the mask 12.

[0021] After the paste is printed on the substrate KB as described above, when the substrate KB is separated from the mask 12 due to plate separation, a part of the paste Pst in the printing aperture 12K flows around to the lower surface of the mask 12 and the paste Pst adheres to the lower surface of the mask 12. Therefore, if the mask 12 is brought into contact with the substrate KB as it is when attempting to print on the next substrate KB, the substrate KB will be soiled by the paste Pst adhering to the mask 12.

[0022] The mask cleaner 15 included in the screen printing apparatus 10 in this embodiment has a function of removing the paste Pst adhering to the lower surface of the mask 12 after the printing of the paste Pst on the substrate KB is completed and before the next substrate KB is brought into contact with the mask 12. Hereinafter, the configuration and operation of the mask cleaner 15 will be described.

[0023] In Figure 1, the mask cleaner 15 has a dispensing roller 23 and a take-up roller 24 inside the housing 21, with a paper material 22 stretched between the dispensing roller 23 and the take-up roller 24. The dispensing roller 23 dispenses the paper material 22, and the take-up roller 24 operates to take up the paper material 22 dispensed from the dispensing roller 23.

[0024] In Figure 1, a suction nozzle 25 with its suction opening facing upward is provided between the dispensing roller 23 and the winding roller 24. The suction nozzle 25 pushes up the paper material 22 between the dispensing roller 23 and the winding roller 24 from below.

[0025] The mask cleaner 15 is moved horizontally (arrow C shown in Figure 1) by a mask cleaner moving mechanism 15M, which consists of, for example, a ball screw mechanism. The movement of the mask cleaner 15 by the mask cleaner moving mechanism 15M is controlled by a control device 16 (Figure 1).

[0026] In Figure 1, a suction force generating unit 26 is provided on the outside of the housing 21 to generate suction force. The suction force generating unit 26 is connected to the suction nozzle 25 by a suction pipe 27. As shown in Figure 1, the suction force generating unit 26 includes a blower motor 31 and a fan 32 that is rotationally driven by the motor 31. The operation of the motor 31 is controlled by a control device 16 (Figure 1).

[0027] When the motor 31 of the suction force generating unit 26 operates and the fan 32 rotates, a suction force is generated at the suction nozzle 25 through the suction pipe 27. As a result, the suction nozzle 25 can draw in air via the paper member 22.

[0028] The graph in Figure 3 shows an example of the relationship between the drive frequency F of the motor 31 (horizontal axis) and the suction force generated at the suction nozzle 25 (vertical axis). As shown in this graph, the suction force generated at the suction nozzle 25 is greater when the drive frequency F of the motor 31 is large, and is smaller when the drive frequency F of the motor 31 is small. Here, "suction force generated at the suction nozzle" corresponds to the amount of air that the suction nozzle 25 sucks in per unit time.

[0029] In this embodiment, the maximum value of the drive frequency F is set to F1, and the minimum value is set to F4. Between the maximum value F1 and the minimum value F4, two intermediate values ​​are set: a first intermediate value F2 and a third intermediate value F3 (F2 > F3). The control device 16 can select any value from these four values ​​(F1, F2, F3, F4) and set that selected value as the drive frequency F.

[0030] When the control device 16 performs mask cleaning to remove paste Pst adhering to the lower surface of the printed mask 12 using the mask cleaner 15, it moves the mask cleaner 15 horizontally using the mask cleaner moving mechanism 15M while the upper surface of the paper member 22 of the mask cleaner 15 is in contact with the lower surface of the mask 12 (arrow C shown in Figure 4). As a result, the paper member 22 slides along the lower surface of the mask 12, and the paste Pst adhering to the lower surface of the mask 12 is wiped away by the paper member 22.

[0031] As described above, the control device 16 moves the mask cleaner 15 while generating negative pressure with the suction force generating unit 26, thereby generating suction force in the suction nozzle 25. As a result, the suction nozzle 25 sucks in air and also sucks in the paste Pst in the printing opening 12K of the mask 12. The sucked paste Pst in the printing opening 12K enters the suction pipe 27 from the suction nozzle 25 via the paper member 22, and is discharged to the outside of the mask cleaner 15 through the paste discharge passage 27E branched from the suction pipe 27 (arrow D shown in Figure 4).

[0032] In this embodiment, the motor 31, fan 32, suction nozzle 25, and suction piping 27 constitute a suction unit 40 (Figure 4) that is electrically driven to draw in air. The mask cleaner 15 is a cleaning means that uses the suction unit 40 to draw in the paste Pst adhering to the mask 12 after printing, along with the air, to clean the mask 12.

[0033] Next, the flow of the screen printing operation (screen printing method) performed in the screen printing apparatus 10 with this configuration will be explained based on the flowchart shown in Figure 5. Before performing the first print on the substrate KB, the screen printing apparatus 10 sets the initial value of the drive frequency F of the motor 31 as a setting parameter for the suction force generated by the suction nozzle 25 during mask cleaning (step ST1). Specifically, one of the four selectable drive frequency F values ​​(F1, F2, F3, F4) mentioned above is selected, and that selected value is set as the initial value of the drive frequency F of the motor 31.

[0034] After setting the initial value of the motor 31's drive frequency F in step ST1, the control device 16 prints paste Pst onto the substrate KB (step ST2, printing process). Once printing is complete, the mask cleaner 15 performs mask cleaning in the manner described above (step ST3, mask cleaning process). Mask cleaning may be performed after printing is completed on one substrate KB, or after printing is completed on multiple substrates KB.

[0035] Once mask cleaning is complete, the cleanliness of the mask 12 is inspected (Step ST4, Inspection Process). This inspection is performed by moving the camera 14 into the area below the mask 12 after the mask cleaner 15 has been retracted (arrow B shown in Figure 6), and having the camera 14 image the printed aperture 12K of the mask 12 located above the camera 14 (Figure 6). After the inspection of the cleanliness of the mask 12 by the camera 14 is complete, the control device 16 determines whether the cleanliness of the mask 12 after the paste Pst has been removed is good or bad (whether the cleanliness was good or not) based on the results (image) obtained from the imaging by the camera 14 (Step ST5, Determination Process).

[0036] The control device 16 makes the above determination by checking whether the amount of remaining paste Pst in all printed apertures 12K inspected (imaged) by the camera 14 is below a certain standard. If the amount of remaining paste Pst in all printed apertures 12K is below a certain standard, the control device 16 determines that the cleaning condition is good. On the other hand, if the amount of remaining paste Pst in all or some of the printed apertures 12K is not below a certain standard, the control device 16 determines that the cleaning condition is not good.

[0037] Based on the above judgment, if the cleaning condition was good, it means that the drive frequency F of the motor 31 set during that cleaning was at least not too low (it was appropriate or too high). Conversely, if the cleaning condition was not good, it means that the drive frequency of the motor 31 set during that cleaning was too low (and therefore inappropriate).

[0038] If the control device 16 determines in step ST5 that the mask 12 is clean, it then determines whether there is another circuit board KB to be printed (step ST6). If there is no next circuit board KB to be printed, it terminates the printing operation. If there is another circuit board KB to be printed, it determines whether the drive frequency of the motor 31 set at that time is the minimum value among the possible values ​​(in this case, whether the drive frequency F is F4) (step ST7). If the drive frequency F of the motor 31 set at that time is the minimum value among the possible values, it returns to step ST2 and proceeds to printing the next circuit board KB.

[0039] On the other hand, if the drive frequency F of the motor 31 set at that time in step ST7 is not the minimum value among the possible values, the control device 16 lowers the drive frequency F of the motor 31 (step ST8), then prints the next board KB (step ST2), and then performs mask cleaning (step ST3). Note that "lowering the drive frequency F" means changing the drive frequency F of the motor 31 to a value lower than the value set at that time.

[0040] In the screen printing apparatus 10 of this embodiment, the control device 16 functions as a determination unit that determines whether the cleaning state of the mask 12 is good or bad based on the results of inspection by the camera 14, which acts as an inspection unit. Furthermore, when the control device 16 determines that the cleaning state of the mask 12 is good, it functions as a cleaning control unit that performs cleaning of the next mask 12 with the suction force of the suction unit 40 reduced.

[0041] As described above, if the drive frequency F of the motor 31 is reduced in step ST8, the mask cleaning after printing (step ST3) performed in the next step ST2 will use a smaller suction force to suck up the paste Pst than the previous time. Therefore, if the drive frequency F of the motor 31 set in the previous mask cleaning was excessive, the value of the drive frequency F can be reduced to an appropriate value, thereby reducing the power consumption required for the electric drive of the motor 31. Thus, according to the screen printing apparatus 10 in this embodiment, mask cleaning can be performed with appropriate power consumption.

[0042] If the control device 16 determines in step ST5 that the mask 12 is not cleaned properly after the inspection (step ST4) following the mask cleaning (step ST3) performed in step ST2, which proceeds directly from step ST1, or step ST2, which returns from step ST8, then it determines whether the drive frequency F of the motor 31 set at that time is the maximum value among the possible values ​​(step ST9). If the drive frequency F of the motor 31 set at that time is the maximum value among the possible values, the control device 16 returns to step ST2 and performs (re-executes) the cleaning of the mask 12.

[0043] On the other hand, if the drive frequency of the motor 31 set at step ST9 is not the maximum value among the possible values, the control device 16 increases the drive frequency of the motor 31 (step ST10) and then returns to step ST2 to perform (re-execute) cleaning of the mask 12. Note that "increasing the drive frequency F" means changing the drive frequency F of the motor 31 to a value greater than the value set at that time.

[0044] In this embodiment, the control device 16, acting as a cleaning control unit, increases the suction force of the suction unit 40 and re-executes the cleaning of the mask 12 when it determines, as a determination unit, that the cleaning state of the mask 12 is not good.

[0045] When the control device 16 re-executes mask cleaning in step ST3 after increasing the drive frequency F of the motor 31 in step ST10, it will suck up the paste Pst with a greater suction force than during the previous mask cleaning. Therefore, even if the previous mask cleaning was performed with insufficient suction force, this deficiency will be resolved in the re-executed mask cleaning, and the mask 12 will be cleaned to a good state after the mask cleaning. If the subsequent inspection (step ST4) and subsequent judgment (step ST5) determine that the mask 12 is not cleaned to a good state again, the process proceeds to step ST9, and if possible, the drive frequency F of the motor 31 is increased again (step ST10), and the mask cleaning is performed again (step ST3).

[0046] The description of this embodiment is as described above, and it includes the following technical items (screen printing apparatus 10 and screen printing method).

[0047] (Item 1) A screen printing apparatus (screen printing apparatus 10) comprising: a mask (mask 12) provided with a printing opening (printing opening 12K); a printing unit (squeegee 13) that prints paste (paste Pst) onto a substrate (substrate KB) through the printing opening of the mask; a mask cleaner (mask cleaner 15) that cleans the mask by sucking up the paste adhering to the mask after printing along with the air using an electrically driven suction unit that sucks up air; an inspection unit (camera 14) that inspects whether the mask is clean after the paste has been removed; and a cleaning control unit (control device 16) that, based on the results of the inspection by the inspection unit, determines that the mask is clean and performs the next mask cleaning with reduced suction power of the suction unit.

[0048] The screen printing apparatus described in item 1 performs the next mask cleaning with reduced suction power if the mask is clean after the previous cleaning. Therefore, if the suction power of the suction unit is excessive, it will be adjusted to an appropriate value, reducing the power consumption required for the electric drive of the suction unit, and consequently lowering the running costs of the screen printing apparatus. Thus, the screen printing apparatus described in item 1 can perform mask cleaning with appropriate power consumption.

[0049] (Item 2) The screen printing apparatus according to item 1, wherein the suction unit is configured to suck up paste together with air by negative pressure generated by the operation of the motor, and the cleaning control unit reduces the suction force of the suction unit by lowering the driving frequency of the motor.

[0050] Item 2 states that if the suction unit has a specific configuration in which the paste is sucked up along with air by the negative pressure generated by the operation of the motor, the suction force of the suction unit can be reduced by lowering the motor's drive frequency.

[0051] (Item 3) The screen printing apparatus according to item 1, wherein the cleaning control unit increases the suction force of the suction unit and re-executes the cleaning of the mask when the determination unit determines that the cleaning state of the mask is not satisfactory.

[0052] The screen printing apparatus described in item 3 will re-perform mask cleaning with increased suction power if the mask is not cleaned properly after the initial cleaning. Therefore, even if the previous mask cleaning was judged to be inadequate due to insufficient suction power, the re-cleaning process can resolve the issue.

[0053] (Item 4) The screen printing apparatus according to item 3, wherein the suction unit is configured to suck up paste together with air by negative pressure generated by the operation of the motor, and the cleaning control unit increases the suction force of the suction unit by increasing the driving frequency of the motor.

[0054] Item 4 states that if the suction unit has a specific configuration in which the paste is sucked up along with air by the negative pressure generated by the operation of the motor, the suction force of the suction unit can be increased by increasing the motor's drive frequency.

[0055] (Item 5) A screen printing method comprising: a printing step of printing paste (paste Pst) onto a substrate (substrate KB) through a printing opening (printing opening 12K) provided in a mask (mask 12); a mask cleaning step of cleaning the mask by using an electrically driven suction unit (suction unit 40) to suck up the paste adhering to the mask in the printing step along with the air; an inspection step of inspecting the clean state of the mask after the paste has been removed; and a determination step of determining whether the clean state of the mask is good based on the results of the inspection in the inspection step, wherein if the determination step determines that the clean state of the mask is good, the mask cleaning step is performed on the next mask with the suction force of the suction unit reduced; and if the determination step determines that the clean state of the mask is not good, the mask cleaning step is re-executed with the suction force of the suction unit increased.

[0056] In the screen printing method described in item 5, if the mask is clean after the initial cleaning, the suction power of the suction unit is reduced when performing the next mask cleaning step. This reduces the suction power of the suction unit if it was excessive, bringing it closer to an appropriate value, thereby saving power consumption required for the electric drive of the suction unit and consequently lowering the running costs of the screen printing device. Furthermore, if the mask is not clean after the mask cleaning step, the suction power of the suction unit is increased when performing the next mask cleaning step. Therefore, even if the previous mask cleaning was judged to be inadequate due to insufficient suction power, the subsequent mask cleaning can resolve the inadequate condition. Thus, according to the screen printing method described in item 5, mask cleaning can be performed with appropriate power consumption.

[0057] Although this embodiment has been described so far, the technology of this disclosure is not limited to what has been described above, and various modifications are possible. For example, in the embodiment described above, there were four possible values ​​for the drive frequency F of the motor 31: F1, F2, F3, and F4, but this is just one example, and there can be any number of values, as long as there are two or more.

[0058] Furthermore, the inspection unit for checking the cleanliness of the mask 12 after the paste Pst has been removed was a camera 14 that imaged the mask 12 from below after the substrate KB had been separated from the mask 12 in the above embodiment, but this is just one example, and it does not have to be a camera 14. Therefore, the inspection unit may be an inspection device or the like that is set downstream of the screen printing apparatus 10 and images and inspects the printing state of the paste Pst on the substrate KB that has been discharged from the screen printing apparatus 10. [Industrial applicability]

[0059] The present invention provides a screen printing apparatus and a screen printing method that can perform mask cleaning with appropriate power consumption. [Explanation of Symbols]

[0060] 10 Screen printing device 11. Substrate support section 12 masks 12K printing aperture 13 squeegee 14. Camera (Inspection Department) 15. Mask Cleaner (Cleaning Method) 16 Control device (determination unit) (cleaning control unit) 22 Paper components 23. Roller 24 winding rollers 25 Suction nozzle 31 Motor 32 Fans 40 Suction part Pst Paste KB board

Claims

1. A mask with a printed opening, A printing unit that prints paste onto a substrate through the printing opening of the mask, A cleaning means that uses an electrically driven suction unit to suck up the paste adhering to the mask after printing, along with the air, to clean the mask. An inspection unit for inspecting the cleanliness of the mask after the paste has been removed, A determination unit that determines whether the mask is clean or not based on the results of the inspection performed by the inspection unit, When the determination unit determines that the mask is in a good cleaning state, the cleaning control unit performs cleaning of the next mask while reducing the suction force of the suction unit, A screen printing apparatus having a screen printing device.

2. The screen printing apparatus according to claim 1, wherein the suction unit is configured to suck up paste together with air by negative pressure generated by the operation of the motor, and the cleaning control unit reduces the suction force of the suction unit by lowering the driving frequency of the motor.

3. The screen printing apparatus according to claim 1, wherein the cleaning control unit, when the determination unit determines that the cleaning state of the mask is not satisfactory, increases the suction force of the suction unit and re-executes the cleaning of the mask.

4. The screen printing apparatus according to claim 3, wherein the suction unit is configured to suck up paste together with air by negative pressure generated by the operation of the motor, and the cleaning control unit increases the suction force of the suction unit by increasing the driving frequency of the motor.

5. A printing process in which paste is printed onto a substrate through a printing opening provided in a mask, A mask cleaning process is performed by using an electrically driven suction unit to suck up the paste adhering to the mask during the printing process along with the air, thereby cleaning the mask. An inspection step to inspect the cleanliness of the mask after the paste has been removed, The process includes a determination step that determines whether the mask is clean based on the results of the inspection performed in the inspection step, A screen printing method comprising: if the determination step determines that the mask is clean, the mask cleaning step for the next mask is performed with the suction force of the suction unit reduced; and if the determination step determines that the mask is not clean, the mask cleaning step is re-executed with the suction force of the suction unit increased.

Images