JP2005067058A - Screen printing device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screen printing device capable of executing mask cleaning with an appropriate cleaning execution pattern at all times during printing operation, and a screen printing method. <P>SOLUTION: In the screen printing, printing operation is repeated while periodically cleaning the mask plate from a lower surface side with a cleaning unit 20. The substrate surface after printing is observed with a camera 17 to determine the printing state with a determination section 40d. In accordance with the determination result and a prescribed cleaning guide, the cleaning execution pattern to be executed by the cleaning unit 20 is updated with a cleaning condition setting section 40c. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a screen printing apparatus and a screen printing method for printing paste such as cream solder or conductive paste on a substrate.

  In an electronic component mounting process, screen printing is used as a method for printing paste such as cream solder or conductive paste on a substrate. In this method, a mask plate provided with a pattern hole in accordance with a printing target portion is brought into contact with the substrate, a paste is supplied onto the mask plate, and a squeegee is slid on the substrate through the pattern hole. The paste is printed.

  During the printing operation, cream solder that protrudes from the printing area on the substrate adheres to the lower surface of the mask plate, or cream solder that has not been completely transferred onto the substrate remains in the opening of the mask plate. Pollution occurs. Such contamination by cream solder hinders normal printing on the subsequent substrate, and therefore it is necessary to perform cleaning to remove these cream solders.

For this reason, conventionally, a screen printing apparatus provided with a cleaning device that removes cream solder remaining on the lower surface side of the mask plate by scraping or wiping is known (see, for example, Patent Document 1). In such a screen printing apparatus, the mode and interval of the cleaning operation are set in advance, and when the number of printed sheets counted for each printing operation reaches the preset number of cleaning intervals, the cleaning apparatus automatically The cleaning of the lower surface of the mask plate is executed in the set cleaning mode.
Japanese Patent Laid-Open No. 2-80250

  However, in the process of repeatedly performing the printing operation on the substrate, the degree of contamination of the mask plate is not always constant, and the degree of contamination may vary depending on changes in the properties of the cream solder used. For this reason, as in the above-described prior art example, when cleaning is performed in a preset cleaning mode or interval, the cleaning is not necessarily performed under appropriate conditions, and the mask plate remains in a state in which the contamination has progressed. There has been a case where the print quality is deteriorated by repeatedly executing the printing. In order to avoid such inconvenience, it is necessary to adjust the cleaning conditions while always observing the contamination state of the mask plate during the printing operation, and this operation requires a great deal of labor and time. It was.

  Therefore, an object of the present invention is to provide a screen printing apparatus and a screen printing method that can always perform mask cleaning with an appropriate cleaning execution pattern during a printing operation.

The screen printing apparatus of the present invention is a screen printing apparatus for printing a paste on a substrate through the pattern hole by bringing a mask plate provided with a pattern hole into contact with the substrate and sliding a squeegee on the mask plate. A printing state determination means for determining a printing state by observing the surface of the substrate after printing, and a mask plate from the lower surface side by sliding a cleaning head against the lower surface of the mask plate. Based on a cleaning mechanism for cleaning, a cleaning execution pattern storage unit for storing a cleaning execution pattern including a cleaning mode and a cleaning execution interval by the cleaning mechanism, a predetermined cleaning guideline and a determination result of the printing state determination unit The aforementioned A cleaning execution pattern setting means for setting a grayed execution pattern, and a cleaning control means for controlling the cleaning mechanism in accordance cleaning execution patterns set.

  According to the screen printing method of the present invention, a mask plate provided with a pattern hole is brought into contact with the substrate, and a squeegee is slid on the mask plate to print a paste on the substrate, and a cleaning mechanism. A screen printing method for cleaning the mask plate from the lower surface side by bringing a cleaning head into contact with and sliding on the lower surface of the mask plate, and in the process of performing the printing operation and cleaning, the surface of the substrate after printing And determining a printing state by the printing state determination unit, and a cleaning execution pattern including a cleaning mode and a cleaning execution interval by the cleaning mechanism, a predetermined cleaning guideline and a determination result of the printing state determination unit In And a cleaning execution pattern updating step of updating Zui.

  According to the present invention, in the process of performing the printing operation and the cleaning, the surface of the substrate after printing is observed, the printing state is determined by the printing state determination unit, the predetermined cleaning pointer and the printing state determination unit By updating the cleaning execution pattern including the cleaning mode and the cleaning execution interval based on the determination result, the mask cleaning can always be executed with an appropriate cleaning execution pattern.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a screen printing apparatus according to an embodiment of the present invention, FIG. 2 is a structural explanatory view of a cleaning unit of the screen printing apparatus according to an embodiment of the present invention, and FIGS. FIG. 5 is a block diagram showing a configuration of a control system of the screen printing apparatus according to the embodiment of the present invention, and FIG. 6 is a screen printing apparatus according to the embodiment of the present invention. FIG. 7, FIG. 8, FIG. 9 are flow charts of mask cleaning execution pattern setting processing in the screen printing method of one embodiment of the present invention, and FIG. 10 is one embodiment of the present invention. FIG. 11 is a flowchart of tact-up processing in the screen printing method according to the embodiment of the present invention.

  First, the structure of the screen printing apparatus will be described with reference to FIG. In FIG. 1, the screen printing apparatus is configured by disposing a screen printing unit 10 above a substrate positioning unit 1. The substrate positioning unit 1 is configured by stacking a Y-axis table 2, an X-axis table 3, and a θ-axis table 4, and further placing a Z-axis table 5 thereon. A substrate holder 6 that holds the substrate 8 is provided on the Z-axis table 5. The substrate 8 is carried onto the substrate holding unit 6 by a carry-in conveyor (not shown), and is sandwiched from both sides by the clamper 7 so that the position is fixed.

A screen printing unit 10 disposed above the substrate positioning unit 1 includes a mask plate 12 extended on a holder frame 11. The mask plate 12 is provided with a pattern hole corresponding to the object to be printed. A squeegee head 13 is disposed on the mask plate 12, and the squeegee head 13 has a structure in which a squeegee raising / lowering mechanism 15 for raising and lowering the squeegee 16 is provided on a horizontal plate 14, and is moved horizontally by a moving means (not shown). Move in the direction.
By driving the squeegee lifting mechanism 15, the squeegee 16 moves up and down and comes into contact with the upper surface of the mask plate 12.

  As shown in FIG. 3, the squeegee 16 is slid on the mask plate 12 to which cream solder as paste is supplied while the Z-axis table 6 is raised and the lower surface of the mask plate 12 is in contact with the substrate 8. By doing so, cream solder is printed on the substrate 8 through a pattern hole (not shown).

  A camera 17 is disposed on the side of the screen printing unit 10 and above the movement range of the Y-axis table 2. The camera 17 is movable in a horizontal plane by a camera movement table (not shown). By moving the substrate positioning unit 1 along the Y-axis table 2 while the substrate positioning unit 1 holds the substrate 8, the substrate 8 can be positioned below the camera 17. 8 can be imaged to detect the position of the substrate 8 and the printing state of the cream solder on the substrate 8.

  A cleaning unit 20 is disposed on the side of the substrate positioning unit 1 on the Y-axis table 2. By driving the Y-axis table 2, the cleaning unit 20 moves in the Y direction together with the substrate holding unit 6. The cleaning unit 20 will be described with reference to FIG. On the upper surface of the main body 20 a of the cleaning unit 20, a cleaning head 21 is disposed so as to be movable up and down by a cylinder 23. The cylinder 23 is driven by a cylinder driving unit 32.

  The main body 20 a is provided with a supply reel 24 and a take-up reel 25 for the cleaning tape 22. The take-up reel 25 is driven by a motor 26, and the cleaning tape 22 is pulled out from the supply reel 24 by driving the motor 26. The drawn cleaning tape 22 wraps around a sliding surface 21 a provided on the upper surface of the cleaning head 21 and is taken up by a take-up reel 25. The motor 26 is driven by a motor drive unit 31.

  When the cleaning head 21 is raised and the cleaning tape 22 on the sliding surface 21a is pressed against the lower surface of the mask plate 12, the cleaning unit 20 is moved horizontally as shown in FIG. Clean from the bottom side. The cleaning unit 20 is a cleaning mechanism that cleans the mask plate 12 from the lower surface side by bringing the cleaning head 21 into contact with and sliding on the lower surface of the mask plate 12.

  The cleaning head 21 is provided with a suction hole 21 b opened in the sliding surface 21 a, and the suction hole 21 b is connected to the vacuum pump 33. By driving the vacuum pump 33, the cream solder is sucked from the suction hole 21b, and thereby, the cream solder remaining in the pattern hole 12a of the mask plate 12 that is difficult to be removed only by cleaning by wiping can be removed by suction. it can.

  Guide portions 27 and 28 are arranged on the feed path where the cleaning tape 22 drawn from the supply reel 24 reaches the upper surface of the cleaning head 21. The cleaning tape 22 goes around the lower surface side of the guide portion 28 and the upper surface side of the guide portion 27 and is sent to the upper surface of the sliding surface 21a. The guide portion 27 is a hollow tubular member, and a plurality of discharge holes 27 a are provided on the upper surface side of the guide portion 27. The inside of the guide portion 27 is connected to a dispenser 29, and when the dispenser 29 is driven, a cleaning liquid 30 such as cleaning ethanol or isopropanol is discharged from the discharge hole 27a.

  By driving the dispenser 29 in a state where the cleaning tape 22 circulates around the upper surface side of the guide portion 27, the cleaning liquid 30 discharged from the discharge holes 27 a is absorbed by the cleaning tape 22. Thereby, when cleaning the lower surface side of the mask plate 12 with the cleaning tape 22, the cream solder adhered to the lower surface of the mask in a fixed state can be wiped off well while being softened by the cleaning liquid 30.

  That is, in the screen printing apparatus according to the present embodiment, the dry mode in which the cleaning liquid is not supplied to the sliding surface of the cleaning head, the wet mode in which the cleaning liquid is supplied to the sliding surface, the wet mode and the dry mode cleaning are performed in combination. The three operation modes of the combination mode can be properly used as cleaning modes.

  The wet and dry combined mode is an operation mode in which the wet mode is performed during the forward movement and the dry mode is performed during the backward movement in the same cleaning operation in which the cleaning unit 20 is reciprocated on the lower surface of the mask plate 12. By executing the wet and dry combined mode, there is an advantage that the cream solder that has been softened and easily removed by the wet mode can be almost completely wiped off by the dry mode.

  Next, the configuration of the control system of the screen printing apparatus will be described with reference to FIG. In FIG. 5, the control unit 40 includes an input control unit 40a, a cleaning control unit 40b, a cleaning condition setting unit 40c, a determination unit 40d, an image processing unit 40e, a counting unit 40f, and a print control unit 40g. The storage unit 41 includes a cleaning execution pattern storage unit 41a, a print inspection data storage unit 41b, and a control program storage unit 41c. Control processing by each unit of the control unit 40 is performed by executing a control program stored in the control program storage unit 41c of the storage unit 41.

  First, data stored in the storage unit 41 will be described. The cleaning execution pattern storage unit 41a is a cleaning execution pattern storage unit that stores a cleaning execution pattern including a mode for cleaning by the cleaning unit 20 and a cleaning execution interval. The cleaning execution pattern is configured by combining the above-described cleaning mode, the cleaning speed, and the interval at which cleaning is performed. The interval cleaning count 42d is stored.

  Here, the cleaning mode 42a will be described with reference to FIG. As shown in FIG. 6, the cleaning mode is based on the presence / absence of suction from the cleaning head 21 (switching between suction ON and suction OFF), and has the three operations of the dry mode, the wet mode, and the wet / dry combined mode described above. This is a combination of mode and basic options.

  Priorities for selection (suction ON mode is priority 2 and suction OFF mode is priority 1) are set in advance between suction ON and suction OFF, and suction OFF mode is specified unless otherwise specified. Priority is given to selection. This is because the suction OFF mode is simpler in terms of operation, and it is more convenient to select the suction OFF mode as long as the cleaning result is not hindered. The priority order is set for the same reason when selecting the operation mode. As shown in FIG. 7, when there is no special designation, the dry mode is selected with priority.

These mode selection designations are made in accordance with established cleaning guidelines based on knowledge gained from experience, so that the cleaning execution pattern that seems to be the most efficient in practice can be easily determined based on empirical rules. Can be set. In the process of repeatedly performing the cleaning in the dry mode, the cleaning in the wet / dry combined mode is performed once every time the cleaning in the dry mode is performed a predetermined number of times. As a result, the cream solder that remains accumulated without being completely removed by dry cleaning can be periodically cleaned up at predetermined intervals. The cleaning guideline is stored in the storage unit 41.

  The cleaning speed 42b is a moving speed when the cleaning head 21 is slid with respect to the mask plate 12 in the cleaning operation, and is set individually for each substrate type and cleaning mode. As will be described later, in the present embodiment, a cleaning speed that is more suitable and preferably optimum during the printing operation is automatically set and updated.

  The interval print number 42c indicates an execution interval when the cleaning is repeatedly performed in the printing operation, in other words, the number of substrates that can be continuously printed without performing the cleaning. Here, since the dry mode cleaning is preferentially selected as described above, the interval print number 42c means an execution interval when the dry mode cleaning is repeated. The interval cleaning count 42d indicates the cleaning execution interval in the wet / dry combined mode that is executed each time the dry mode cleaning is executed a predetermined number of times.

  The print inspection data storage unit 41b stores print inspection data used when the printed substrate 8 imaged by the camera 17 is recognized by the image processing unit 40e and the printing state is determined by the determination unit 40d. The control program storage unit 41c stores various processing programs such as a printing operation program, an operation program such as a cleaning operation program, a printing state determination program, and a cleaning execution pattern setting program.

  The function of the control unit 40 will be described. The input control unit 40a controls data input from the input unit 34 such as a keyboard or a touch panel, transmits data to the cleaning control unit 40b described below, and writes data to the storage unit 41. The cleaning control unit 40b controls the motor driving unit 31, the cylinder driving unit 32, the vacuum pump 33, and the dispenser 29 that constitute the cleaning unit 20 according to the cleaning execution pattern stored in the cleaning execution pattern storage unit 41a, thereby cleaning the cleaning unit 20b. The cleaning operation of the mask plate 12 by the unit 20 is controlled.

  The cleaning condition setting unit 40c sets a cleaning execution pattern based on the printing state determination result of the determination unit 40d, and the set cleaning execution pattern is stored in the cleaning execution pattern storage unit 41a. Therefore, the cleaning condition setting unit 40c is a cleaning execution pattern setting unit that sets a cleaning execution pattern based on a predetermined cleaning guideline and a determination result of a printing state determination unit described later.

  Here, in the cleaning execution pattern setting by the cleaning condition setting unit 40c, the basic option without suction is preferentially selected based on the cleaning guidelines, and the dry mode is preferentially selected based on the cleaning guidelines, and the cleaning is executed. At this time, the cleaning execution pattern is set so that the wet / dry combination mode is executed at predetermined intervals. The cleaning control unit 40b is a cleaning control unit that controls the cleaning mechanism in accordance with the set cleaning execution pattern.

The determination unit 40d determines the printing state of the cream solder based on the recognition result obtained by recognizing the image obtained by capturing the printed substrate 8 with the camera 17 by the image processing unit 40e. The camera 17, the image processing unit 40e, and the determination unit 40d serve as a print state determination unit that determines the print state by observing the surface of the printed substrate.

  The count unit 40f counts the number of prints printed by the screen printing unit 10 and the number of cleanings performed by the cleaning unit 20, and holds the count value. Here, the number of printed sheets is reset every time cleaning is performed, and the number of cleanings is reset every time wet / dry cleaning is performed. The printing control unit 40g controls the screen printing operation by controlling the substrate positioning unit 1 and the screen printing unit 10.

  This screen printing apparatus is configured as described above, and the screen printing method will be described below with reference to the flowcharts of FIGS. In this screen printing method, the mask plate 12 provided with the pattern holes 12a is brought into contact with the substrate 8, and the squeegee 16 is slid on the mask plate 12, thereby printing the paste on the substrate 8 through the pattern holes 12a. In this method, the mask plate 12 is appropriately cleaned.

  At the start of the screen printing operation, there are preset cleaning execution patterns in the cleaning execution pattern storage unit 41a. However, as long as these existing data are optimal for the substrate to be newly printed, it is guaranteed. is not. For this reason, at the start of the printing work, a process for newly setting a cleaning execution pattern in accordance with the actual work situation is executed for an actual substrate. First, the cleaning execution pattern setting process will be described with reference to FIGS. 7, 8, and 9. FIG.

  At the start (ST1) of the cleaning execution pattern setting process, as shown in FIG. 7, the target print number: N1 is input as an initial value and stored in the cleaning execution pattern 41a. Here, the target print number is a target value (expected value) of the interval print number 42c, and it is unclear at this point whether it can be actually achieved. At this time, as a cleaning mode, the suction OFF mode is selected as a basic option and the dry mode is selected as an operation mode in accordance with the above-described cleaning guidelines.

  Next, an initial printing operation by the screen printing unit 10 is executed (ST2). This initial printing operation is executed on an actual board for a predetermined number of sheets determined by using the above-mentioned target printing number N1 as a guide. Then, after completion of printing the predetermined number of sheets, cleaning is executed in the initial setting mode, that is, in the suction OFF / dry mode (ST3).

  Thereafter, printing for interval measurement is executed. That is, similarly to the initial printing operation, printing is performed on an actual substrate (ST4), and the number of printed sheets is counted by the counting unit 40f every time printing is performed on one substrate (ST5). The count value of the number of sheets is updated. Next, the printed board 8 is imaged by the camera 17 and a solder inspection is performed (ST6). In other words, based on the recognition result obtained by recognizing the acquired image by the image processing unit 40e, the determination unit 40d determines the quality of the print state. If the determination result is OK, the process returns to (ST4) and the printing operation is repeatedly executed.

  If the determination result is NG, it is determined whether or not the count value of the number of printed sheets at that time is equal to or greater than the target number of printed sheets N1 (ST7). If the target print number is N1 or more, the current print number is stored as a new interval print number in the cleaning execution pattern storage unit 41a (ST8), the print number count is reset (ST9), and a tact described later is performed. The process proceeds to the up process (ST10). This tact-up process is performed for the purpose of reducing the time required for cleaning and improving the overall productivity.

  If the target print number N1 is not reached in (ST7), the current print number is stored as a new interval print number (ST11), the print number count is reset (ST12), and wet and dry combined cleaning, that is, Cleaning in the wet / dry combination mode is executed only once (ST13). This wet and dry combined cleaning is performed for the purpose of cleaning up the mask plate. As a result, the cream solder remaining in the lower surface of the mask plate 12 and the pattern hole 12a is almost completely removed, and subsequently executed. The influence on the evaluation of the cleaning result by the suction ON mode is wiped out.

  In this state, the mode is changed to the suction ON mode (ST14), the process proceeds to a cleaning trial in the suction ON mode (ST15), and it is verified whether or not the effect of increasing the number of interval prints can be obtained by the suction ON mode. That is, as shown in FIG. 8, the pre-printing operation is executed here as well (ST16), and then the cleaning in the suction ON mode is executed (ST17). Similarly, printing for interval measurement is executed.

  That is, a printing operation for interval measurement is performed on an actual substrate (ST18), and the number of printed sheets is counted each time printing is performed on one substrate (ST19). Next, similarly, a solder inspection is performed by the determination unit 40d to determine whether the print state is good (ST20). Here, if the inspection result is OK, the process returns to ST18 and the printing operation is repeatedly executed.

  If the inspection result is NG, it is determined whether or not the number of printed sheets at that time is greater than the number of interval printed sheets in the suction OFF mode shown in FIG. 7 (ST21). If “YES” here, the current print number is stored in the cleaning execution pattern storage unit 41a as the interval print number in the suction ON mode (ST22). The count of the number of printed sheets is reset (ST23), and the process proceeds to a tact-up process described later (ST24). This tact-up process is also performed for the purpose of improving the overall productivity by shortening the time required for cleaning.

  If (NO) in (ST20), the count of the number of printed sheets is reset (ST25), and the cleaning in the wet / dry combined mode is executed only once for cleaning up the mask plate 12 (ST26). Then, the mode is changed to the suction OFF mode (ST27), and the interval print sheet number for dry cleaning is determined based on the interval print sheet number in the suction OFF mode (the interval print sheet number set in (ST11) in FIG. 7) ( ST28). The determined interval print number is stored in the cleaning execution pattern storage unit 41a. Thereafter, the process proceeds to an interval setting process for wet and dry combined cleaning (ST29).

  Next, with reference to FIG. 9, the cleaning interval setting process in the wet / dry combined mode will be described. Here, every time the dry mode cleaning is repeated a predetermined number of times, the interval for executing the wet / dry combined mode cleaning executed to clean up the remaining cream solder is set in the same manner as described above. Is.

  In FIG. 9, a printing operation is first performed by the screen printing unit 10 (ST30), and the number of printed sheets is counted each time printing is performed on one substrate (ST31). Here, it is determined whether or not the current print number is the same as the preset interval print number, that is, the interval print number determined in (ST28). If YES, it is determined that the time for performing cleaning has been reached. Then, cleaning in the dry mode is executed (ST33). Then, the number of cleanings is counted (ST34), the count of the number of printed sheets is reset (ST35), and the process returns to (ST30) to repeat printing.

  If it is NO in (ST32), that is, if it is determined that the time for performing cleaning has not yet been reached, a solder inspection is performed to determine whether the printing state is good (ST36). If the inspection result is OK, the process returns to (ST30) and the printing operation is repeatedly executed. If the inspection result is NG, the current number of cleanings is determined as the number of interval cleanings in the wet / dry combination cleaning (ST37), and stored in the cleaning execution pattern storage unit 41a. It should be noted that the wet / dry combined cleaning interval may be stored not in the form of the number of cleanings but in the form of the number of interval prints.

  Thereby, items other than the cleaning speed are determined among the items constituting the cleaning execution pattern. Then, the process proceeds to automatic printing processing (ST38), and in the course of executing automatic printing processing, the above-described tact-up processing (see ST10 and ST24) is executed, whereby the optimum cleaning speed is determined. An optimum cleaning execution pattern in the screen printing for the substrate is determined.

  Here, the automatic printing process will be described with reference to FIG. This automatic printing process is mainly performed in a dry mode cleaning in an actual printing operation in which a large number of substrates are continuously printed, and a wet-dry combined type for the purpose of cleaning up the mask plate 12 every predetermined number of times. The process of intermittently executing the cleaning is automatically performed by controlling the cleaning unit 20 by the cleaning control unit 40b.

  When the automatic printing process is started and the printing operation is executed (ST40), the number of printed sheets is counted (ST41). Then, it is determined whether or not the cleaning to be performed this time is dry cleaning (ST42). If “YES” here, it is determined whether or not the counted number of printed sheets is equal to the interval number of printed sheets for dry cleaning (ST43). If “NO” here, the process returns to the printing operation (ST40) (ST44). If YES, dry cleaning is executed under the set conditions (ST45). Next, the number of printed sheets is reset (ST46), and then the number of cleanings is counted (ST47).

  Thereafter, it is determined whether or not the number of prints obtained by converting the counted number of times of cleaning into the number of times of printing is the same as the interval cleaning number of times 42d of the wet and dry combined cleaning (ST48). Return to (ST49). If YES, the wet and dry combined cleaning is executed (ST50), the number of printed sheets and the number of cleanings are reset (ST51), and the process returns to the printing operation (ST52). If (NO) in (ST42), the process proceeds directly to (ST48), and the current number of cleanings is compared with the number of interval cleanings 42d of the wet / dry combined cleaning.

  Next, tact-up processing (cleaning speed increase processing) will be described with reference to FIG. First, wet / dry cleaning is performed (ST60), and the cleaning speed is increased by a preset speed increment (ST61). Then, the automatic printing process shown in FIG. 10 is executed (ST62). Then, it is determined whether or not cleaning has been performed a predetermined number of times or more without inspection NG (ST63). If YES, the process returns to (ST60), and after performing wet and dry combined cleaning, the cleaning speed is further increased, and so on. Repeat steps.

  If NO is determined in (ST63), the cleaning speed immediately before the inspection NG is output is set as the optimum cleaning speed (ST64) and stored in the cleaning execution pattern storage unit 41a. As a result, the cleaning speed 42b can be set as high as possible without causing NG in the solder inspection, and the tact time required for the cleaning operation can be shortened.

  In the above-described embodiment, an example in which a cleaning execution pattern is newly determined at the start of the printing operation is shown. However, in the process of continuously performing the printing operation on a large number of substrates, FIGS. The cleaning execution pattern determination process shown in FIG. 11 and the tact-up process shown in FIG. 11 may be executed as needed. When it is executed during work, the initial printing operation shown in (ST2) and (ST16) is not necessary, and interval measurement is started after execution of cleaning at an arbitrary time.

  That is, in the above-described screen printing method, in the process of executing the printing operation and the cleaning operation, a determination step of observing the surface of the substrate 8 after printing and determining the printing state by the printing state determination unit, and a predetermined cleaning And a cleaning execution pattern update step of updating the cleaning execution pattern based on the pointer and the determination result of the printing state determination means.

  In the cleaning execution pattern update step, the dry mode is preferentially selected based on the cleaning guideline, and the cleaning execution pattern is set so that the wet / dry combination mode is executed at predetermined intervals when cleaning is executed. Further, the cleaning execution pattern includes the moving speed of the cleaning head 21, and the cleaning execution pattern setting means sets the moving speed of the cleaning head 21 to a more suitable, preferably optimum speed, based on the determination result of the printing state determining means. I am trying to set it.

  As a result, in the process of repeatedly performing the printing operation on the substrate, even when the degree of contamination of the mask plate varies, the mask cleaning can always be performed with an appropriate cleaning execution pattern. It is possible to eliminate the work of adjusting the cleaning conditions while observing the dirty state of the mask plate.

  The screen printing apparatus and the screen printing method of the present invention have the advantage that mask cleaning can always be executed with an appropriate cleaning execution pattern, and screen printing for printing paste such as cream solder or conductive paste on a substrate is possible. Useful in the field.

The side view of the screen printing apparatus of one embodiment of this invention Structure explanatory drawing of the cleaning unit of the screen printing apparatus of one embodiment of the present invention Operation explanatory diagram of a screen printing apparatus according to an embodiment of the present invention Operation explanatory diagram of a screen printing apparatus according to an embodiment of the present invention The block diagram which shows the structure of the control system of the screen printing apparatus of one embodiment of this invention The figure which shows the cleaning execution pattern of the screen printing apparatus of one embodiment of this invention Flowchart of mask cleaning execution pattern setting process in screen printing method of one embodiment of the present invention Flowchart of mask cleaning execution pattern setting process in screen printing method of one embodiment of the present invention Flowchart of mask cleaning execution pattern setting process in screen printing method of one embodiment of the present invention Flow chart of automatic printing process in screen printing method of one embodiment of the present invention Flow chart of tact-up processing in the screen printing method of one embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate positioning part 8 Board | substrate 10 Screen printing part 12 Mask plate 12a Pattern hole 13 Squeegee head 20 Cleaning unit 21 Cleaning head 21a Sliding surface 40b Cleaning control part 40c Cleaning condition setting part 40d Judgment part 41a Cleaning execution pattern memory | storage part

Claims (8)

  A screen printing apparatus for printing a paste on a substrate through the pattern hole by bringing a mask plate provided with a pattern hole into contact with the substrate and sliding a squeegee on the mask plate. A printing state determination means for determining a printing state by observing the surface of the mask, a cleaning mechanism for cleaning the mask plate from the lower surface side by sliding a cleaning head against the lower surface of the mask plate, and the cleaning A cleaning execution pattern storage unit that stores a cleaning execution pattern including a cleaning mode and a cleaning execution interval by a mechanism, and a cleaning execution pattern that is set based on a predetermined cleaning guideline and a determination result of the printing state determination unit. And training execution pattern setting means, the screen printing apparatus characterized by comprising a cleaning control means for controlling the cleaning mechanism in accordance cleaning execution patterns set.   The cleaning mode is based on the presence or absence of suction from the cleaning head, the dry mode in which no cleaning liquid is supplied to the sliding surface of the cleaning head, the wet mode in which the cleaning liquid is supplied to the sliding surface, the dry mode in the same cleaning operation, The operation mode is configured by combining the basic options with the three operation modes of the wet and dry combined mode in which the cleaning in the wet mode is performed together, and the cleaning execution pattern setting unit gives priority to the basic option without suction based on the cleaning guideline. The screen printing apparatus according to claim 1, wherein the screen printing apparatus is selected.   The cleaning execution pattern setting means preferentially selects the dry mode as an operation mode based on the cleaning guideline, and sets the cleaning execution pattern so that the wet / dry combined mode is executed at predetermined intervals when performing cleaning. The screen printing apparatus according to claim 2.   The cleaning execution pattern includes a moving speed of the cleaning head, and the cleaning execution pattern setting unit sets the moving speed to a more suitable speed based on a determination result of the printing state determination unit. Item 4. A screen printing apparatus according to Item 1.   A mask plate provided with a pattern hole is brought into contact with the substrate, and a squeegee is slid on the mask plate to print a paste on the substrate through the pattern hole, and a cleaning mechanism cleans the lower surface of the mask plate. A screen printing method in which the mask plate is cleaned from the lower surface side by abutting and sliding the head, and the surface of the printed substrate is observed in the process of performing the printing operation and cleaning, and the printing state determining means A cleaning process for determining a printing state, and a cleaning execution pattern including a cleaning mode and a cleaning execution interval by the cleaning mechanism are updated based on a predetermined cleaning guideline and a determination result of the printing state determination unit. Screen printing method characterized by comprising a pattern updating step.   The cleaning mode is based on whether or not suction from the cleaning head is a basic option, a dry mode in which cleaning liquid is not supplied to the sliding surface of the cleaning head, a wet mode in which cleaning liquid is supplied to the sliding surface, and wet and Combining the basic options with the three operation modes of the wet and dry combined mode, which also performs cleaning in the dry mode, and prioritizing the basic options without suction based on the cleaning guidelines in the cleaning execution pattern update process 6. The screen printing method according to claim 5, wherein the screen printing method is selected.   In the cleaning execution pattern update step, the dry mode is preferentially selected as the operation mode based on the cleaning guideline, and the cleaning execution pattern is set so that the wet / dry combination mode is executed at predetermined intervals when performing cleaning. The screen printing method according to claim 6. The cleaning execution pattern includes a moving speed of the cleaning head, and in the cleaning execution pattern update step, the moving speed is set to a more suitable speed based on a determination result of the printing state determination unit. Item 6. The screen printing method according to Item 5.

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