JP5723404B2 - Printing device - Google Patents

Description

  The present invention relates to a printing apparatus for printing paste such as cream solder on a printed circuit board or the like.

  Conventionally, a paste such as cream solder or conductive paste supplied on a mask sheet (screen) is moved by a squeegee that moves along the mask sheet, and the printed circuit board (Printed Circuit Circuit) is superimposed on the mask sheet. There is known a screen printing apparatus for printing on a board such as “Board”.

  As one example of this type of screen printing apparatus, Patent Document 1, for example, includes a pair of squeegees that move along a mask sheet. Both squeegees are brought into contact with the area, and the squeegee is repeatedly reciprocated within the run-up area to knead (roll) the paste between the squeegees. By constantly kneading the paste in this way, the state of the paste (such as viscosity) is prevented from changing during standby.

Japanese Patent No. 3298395

  According to the conventional screen printing apparatus described in Patent Document 1, it is considered effective in maintaining a good paste state during printing. However, it is useless to always move the squeegee during standby, especially when the standby time is prolonged or when the standby time occurs frequently, such as in small-lot, high-mix production. This is disadvantageous in reducing running costs. Therefore, there is room for improvement in this respect.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a printing apparatus capable of suppressing running costs while maintaining a good paste state during printing.

In order to solve the above-described problems, the present invention provides a printing apparatus that prints a predetermined paste on a substrate, and includes a mask sheet that includes an opening for printing and is stacked on the substrate, and the mask sheet. The squeegee that prints the paste on the substrate through the opening by moving the paste in a specific direction, and the mask sheet, outside the predetermined printing area including the opening, and in the specific direction A control device that controls the operation of the squeegee so that the paste reciprocates between reference points set in both outer regions, and the control device generates a predetermined interruption period. In the previous printing operation, the squeegee is controlled so that the paste is located at a predetermined extension point outside the reference point at the end of the printing operation. During said interruption period, the squeegee is stopped, in the first printing operation after the interruption period, before Kinobe length point moves the paste toward the printing area the paste directly to the print region The squeegee is controlled to enter and print on the substrate .

  According to this printing apparatus, when an interruption period occurs in the printing operation, the squeegee is stopped, so that power consumption is suppressed. Moreover, after the lapse of the interruption period, the paste starts to move from an extension point outside the reference point, so that the paste moves more than usual. That is, by kneading (rolling) the paste more than usual, it is possible to recover the state such as the viscosity changed during the interruption period. Therefore, the state of the paste at the time of printing, that is, the state of the paste when moving the printing area can be kept good.

  Note that the viscosity and the like of the paste change remarkably as the standing time increases. Therefore, according to the length of the interruption period, the control device sets the extension point at a position farther from the reference point as the interruption period is longer, and controls the squeegee based on the extension point. Is preferred.

  According to this configuration, the longer the interruption period is, the more paste is kneaded, which is effective in maintaining the state of the paste during printing appropriately.

  In this case, for example, the printing apparatus further includes a storage device that stores table data that defines the suspension period or information about the suspension period and the extension point, and the control device includes the suspension period or the According to the information, it is preferable to specify an extension point corresponding to the information from the table data.

  According to this configuration, it is possible to appropriately switch the extension point according to the interruption period.

  The interruption period is, for example, a mask sheet cleaning period or a waiting period for loading a substrate to be processed.

  According to this configuration, it is possible to satisfactorily perform the first printing after cleaning and the subsequent substrate printing.

  As described above, according to the printing apparatus of the present invention, when a printing operation is interrupted, the squeegee is stopped, so that power consumption is suppressed. In addition, after the interruption period has elapsed, the paste is moved from the extension point, so that the paste is suitably kneaded (rolled), whereby the state of the paste changed during the interruption period is recovered. Therefore, it is possible to reduce running costs while maintaining a good paste state during printing.

It is a side view which shows the printing apparatus which concerns on this invention. It is a front view which shows a printing apparatus. It is explanatory drawing explaining operation | movement of a squeegee. 6 is a flowchart illustrating an example of printing operation control by the control device. It is a schematic diagram explaining operation | movement (normal printing operation | movement) of a squeegee. It is a schematic diagram explaining operation | movement (printing operation before and behind cleaning) of a squeegee. 10 is a flowchart illustrating another example of printing operation control by the control device. It is a schematic diagram explaining operation | movement of a squeegee.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
1 and 2 schematically show a printing apparatus according to the present invention. FIG. 1 is a side view (a side view as seen from the side where a printed substrate is carried out), and FIG. 2 is a front view. Each shows a printing device. In each figure, XYZ rectangular coordinate axes are shown to clarify the directional relationship.

  The printing apparatus shown in these drawings is a so-called screen printing apparatus. The printing apparatus has a base 1. On the base 1, a carry-in conveyor 2a, a carry-out conveyor 2b, and a printing stage 3 positioned between the two conveyors 2a and 2b are arranged in the Y direction. The board | substrate P is carried in to the printing stage 3 by the carrying-in conveyor 2a, and after a printing process is given here, it is carried out by the carrying-out conveyor 2b.

  A four-axis unit 10 is disposed on the printing stage 3. The 4-axis unit 10 is for supporting the substrate P and stacking the substrate P on the mask sheet 4 to be described later from the lower side thereof. The substrate P that has been loaded by the loading conveyor 2a is horizontally disposed. It is supported so as to be displaceable in the X direction, the Y direction, the Z direction, and the R (around the Z axis) direction.

  More specifically, the four-axis unit 10 includes a fixed table 11 fixed on the base 1 and an X-axis table 12 movable in the X direction relative to the fixed table 11 in order from the lower side. A Y-axis table 13 movable in the Y direction relative to the X table 12, an R-axis table 14 rotatable about the Z-axis with respect to the Y-axis table 13, and the R-axis table 14 And a lift table 15 that can be lifted up and down. A support unit 16 is provided on the lifting table 15, and the substrate P is supported by the support unit 16, so that the substrate P is driven in the X direction and Y by driving the tables 12, 13, 14, and 15. Move in direction, Z direction and R direction.

  The support unit 16 includes a conveyor 19 that supports the substrate P so that the substrate P can be conveyed in the Y direction, a support mechanism 17 for supporting the substrate P, and a clamp mechanism 18 for clamping the substrate P. That is, the support unit 16 receives the substrate P from the carry-in conveyor 2a onto the conveyor 19, lifts the substrate P from the conveyor 19 by supporting the substrate P from the lower side (back surface side) by the support mechanism 17, and holds the substrate P. The clamp mechanism 18 clamps (clamps) from both sides in the X direction. As a result, the substrate P is positioned and fixed at a predetermined position on the lifting table 15.

  A mask sheet (screen) 4 is arranged substantially horizontally above the printing stage 3. A printing head 6 for moving a paste (a conductive binder such as cream solder or conductive paste) along the mask sheet 4 is disposed above the mask sheet 4.

  The mask sheet 4 is a plate-like member made of, for example, stainless steel in which an opening for printing is formed. The mask sheet 4 is stretched on a predetermined frame and is exchangeably incorporated into the printing apparatus via the frame. Yes. A movable cleaning device 9 is arranged immediately below the mask sheet 4. When the printing operation proceeds, the cleaning device 9 slides along the lower surface of the mask sheet 4 at a certain timing. The paste adhering to the lower surface and the opening of the mask sheet 4 is removed. The cleaning device 9 is arranged at a predetermined retracted position (position shown in FIG. 1) outside the mask sheet during the printing operation.

  The print head 6 (hereinafter simply referred to as the head 6) is supported so as to be movable in the X direction and the Z direction, and is driven by a servo motor or the like. Specifically, at a position above the mask sheet 4, a pair of fixed rails 7 extending in the X direction, a head support member 5 extending in the Y direction and supported movably on each fixed rail 7, and a servo motor 8 are provided. A drive mechanism such as a screw feed mechanism for driving the head support member 5 is provided as a drive source. A fixed rail 22 extending in the Z direction is fixed to the head support member 5, and the head 6 is movably mounted on the fixed rail 22, and screw feed for driving the head 6 using a servo motor 23 as a drive source. It is connected to a drive mechanism such as a mechanism. With this configuration, the print head 6 moves in the X direction integrally with the head support member 5 by driving the servo motor 8, and the head 6 moves in the Z direction with respect to the head support member 5 by driving the servo motor 23. .

  The head 6 is equipped with a squeegee 6a. The squeegee 6a expands the paste on the mask sheet 4 and moves the squeegee 6a along the mask sheet 4. The squeegee 6a is made of, for example, a hard urethane elongated in the Y direction or a plate member made of stainless steel. The squeegee 6a is pressed onto the mask sheet 4 when the head 6 moves in the Z direction with respect to the head support member 5. In this state, the head 6 moves in the X direction integrally with the head support member 5. It slides along the mask sheet 4. In this manner, the paste supplied onto the mask sheet 4 is moved in the X direction while the squeegee 6 a slides along the mask sheet 4, so that the paste is formed on the substrate P through the opening of the mask sheet 4. Printed.

  As schematically shown in FIG. 3, the squeegee 6a is supported by the head 6 so as to be swingable via a holder 6b, and is used as a drive mechanism using a servo motor 24 (shown in FIG. 2) as a drive source. It is connected. With this configuration, the posture of the squeegee 6a is switched between a state where the pressing surface of the paste faces one side in the X direction and a state facing the other side, and an angle (attack angle) formed between the pressing surface and the mask sheet 4 Can be changed. That is, while the head 6 reciprocates in the X direction, the posture of the squeegee 6a is switched so that the pressing surface faces the traveling direction at the time of forward movement and backward movement, so that the printing and the head at the time of head forward movement are performed. Printing at the time of returning is performed by one squeegee 6a.

  The printing apparatus includes a control device 30 that controls the printing operation, and the operations of the 4-axis unit 10 and the head 6 are controlled by the control device 30 in an integrated manner. The control device 30 is a control device based on a well-known microcomputer, and includes a central processing unit (CPU) that executes a program, a memory that stores a program and various data, such as a ROM and a RAM, and an electric An input / output (I / O) bus for inputting and outputting signals is provided, and the servo motor 23 and the like are all electrically connected to the control device 30.

  Next, control of the printing operation by the control device 30 will be described with reference to FIGS. 4 and 5. FIG. 4 is a flowchart showing the operation control of the head 6, and FIG. 5 is a schematic diagram for explaining the operation of the head 6 based on the control.

  First, prior to the control shown in FIG. 4, the control device 30 executes the following print preparation. That is, the control device 30 controls the 4-axis unit 10 so that the trial substrate received by the 4-axis unit 10 is placed at a predetermined position on the mask sheet 4. Then, the head 6 is disposed at a predetermined position on one end side in the X direction, and the squeegee 6a is brought into contact with or close to the mask sheet 4 at a predetermined attack angle. Then, while the head 6 is reciprocated in the X direction, the posture of the squeegee 6a is switched so that the pressing surface faces the traveling direction at the time of forward movement and backward movement, so that the paste is applied on the mask sheet 4 a plurality of times. Kneading (rolling) while reciprocating. After that, as shown by the solid line in FIG. 5A, the paste S (squeegee 6a) is placed at a predetermined reference point P1, and after the trial substrate is unloaded, the production substrate P is transferred to the four-axis unit 10. The mask sheet 4 is overlaid by the above.

  When the above preparation operation is completed, the control device 30 starts printing according to the flowchart of FIG. 4 (step S1). Specifically, the paste S (squeegee 6a) is moved along the mask sheet 4 from the reference point P1 by moving the head 6 in the X direction. Here, as shown in FIG. 5A, the reference point P1 is outside the predetermined printing area E including the printing opening (all openings) in the mask sheet 4, and the printing area. They are set at symmetrical positions on both outer sides in the X direction across E. The section from the reference point P1 to the printing area E is a run-up section Er of the paste S, and the paste S moves onto the print area E while being kneaded (rolled) in the run-up section Er.

  When printing is started, the control device 30 determines whether or not the current printing is printing immediately before the cleaning of the mask sheet 4 by the cleaning device 9 (step S3). If it is determined that it is not immediately before cleaning (NO in step S3), the control device 30 moves the paste S (squeegee 6a) to the reference point P1 on the opposite side across the printing area E (step S5). ). Then, in order to start the next printing operation from this reference point P1, as shown by the solid line in FIG. 5 (b), after the squeegee 6a is reversed, the squeegee 6a comes into contact with or approaches the mask sheet 4. (Step S9), thereby ending this flowchart.

  On the other hand, if it is determined in step S3 that it is immediately before cleaning (YES in step S3), the control device 30 pastes the paste S up to the extension point P2 outside the reference point P1, as shown in FIG. (Squeegee 6a) is moved (step S7), and the process proceeds to step S9. As a result, as shown by the solid line in FIG. 6B, the squeegee 6 a is brought into contact with or approached to the mask sheet 4 with the posture of the squeegee 6 a reversed. The extension point P2 is set at a position on the mask sheet 4 that is further outside the reference points P1 in the X direction and symmetrical with respect to the print region E.

  Here, the operations of the head 6 and the like based on the operation control by the control device 30 are summarized as follows. That is, in this printing apparatus, normally, as shown in FIGS. 5A and 5B, the head 6 moves with reference to the reference point P1 set outside the printing area E, so that the paste S ( The squeegee 6a) reciprocates along the mask sheet 4 between these reference points P1. Thereby, the paste S is printed on the substrate P through the opening of the mask sheet 4 when the head 6 moves forward and backward.

  When the printing operation is interrupted due to the cleaning of the mask sheet 4, the paste S (squeegee 6 a) passes over the reference point P 1 and passes through the printing operation immediately before the cleaning, as shown in FIG. It is moved to the outer extension point P2 (step S7). During cleaning (during the interruption of printing), the squeegee 6a is stopped. When the cleaning is completed, the paste S (squeegee 6a) is extended at the extension point P2 as shown in FIG. Moved from.

  According to the printing apparatus as described above, when the printing job is interrupted due to the cleaning of the mask sheet 4, the squeegee 6a is stopped as described above, so that power consumption is suppressed. Moreover, after the lapse of the interruption period, the paste S starts to move from the extension point P2 outside the reference point P1, so that the paste S is kneaded (rolled) more than usual. As a result, the state of the paste S in the printing region E is ensured satisfactorily. That is, in the normal printing operation, the paste S is moved on the printing region E while being kneaded (rolled) in the run-up section Er between the reference point P1 and the printing region E, but the first printing operation after cleaning is performed. Then, by starting the movement of the paste S (squeegee 6a) from the extension point P2 outside the reference point P1, the run-up section Er is expanded by that amount (distance δ shown in FIG. 6B). A large amount of paste S is kneaded by the distance δ. Therefore, the state such as the viscosity of the paste S changed during the cleaning can be sufficiently recovered and moved to the printing region E.

  Therefore, according to this printing apparatus, while maintaining the state of the paste S at the time of printing, the squeegee can be stopped and the power consumption can be suppressed during the interruption period of the printing work. There is an advantage that the running cost can be suppressed as compared with Patent Document 1) of the background art.

(Second Embodiment)
The printing apparatus according to the second embodiment has the same basic configuration as that of the printing apparatus according to the first embodiment, except for the following points.

  In this printing apparatus, instead of the flowchart of FIG. 4, after the printing is completed, the control device 30 controls the head 6 and the like according to the flowchart shown in FIG. 7.

  First, the control device 30 determines whether or not the time until the substrate P is carried into the printing device after completion of the previous printing has exceeded a preset time (step S11). That is, it is determined whether or not a waiting time of a certain time or more has occurred due to the above-described cleaning of the mask sheet 4, waiting for the subsequent substrate P to be carried in, or the like. If it is determined that the set time has not been exceeded (NO in step S11), the control device 30 moves the head 6 in the X direction as shown in FIG. (Squeegee 6a) is moved to a reference point P1 on the opposite side across the print area E (step S13). Then, in order to start the next printing operation from this reference point P1, as shown by the solid line in FIG. 5B, the posture of the squeegee 6a is reversed (step S19), and then this flowchart is ended.

  On the other hand, if it is determined in step S11 that the set time has been exceeded (YES in step S11), the control device 30 changes the posture of the squeegee 6a as shown in FIGS. 8 (a) and 8 (b). The paste S (squeegee 6a) is temporarily moved from the reference point P1 to the outer extension point P2 by moving the head 6 in the direction opposite to the printing area E (step S15). Then, as shown in FIG. 8C, after the posture of the squeegee 6a is reversed again, the head 6 is moved in the X direction, whereby the paste S (squeegee 6a) is extended along the mask sheet 4 at the extension point P2. To a reference point P1 on the opposite side across the printing area E (step S17), and then the process proceeds to step S19.

  That is, in the printing apparatus of the first embodiment, the paste S (squeegee 6a) is disposed in advance at the extension point P2 before the standby time for cleaning the mask sheet 4 occurs, and this extension is performed after the standby time has elapsed. The paste S (squeegee 6a) is moved from the point P2. On the other hand, in the printing apparatus according to the second embodiment, after the standby time has occurred, the paste S (squeegee 6a) is once moved from the reference point P1 to the extension point P2, and then from the extension point P2 to the printing region E. The paste S (squeegee 6a) is moved toward the front.

  Thus, also in the printing apparatus of the second embodiment, after the standby time has elapsed, the movement of the paste S is started from the extension point P2 outside the reference point P1, so that the running section Er is more than the normal printing operation. As a result, more paste S is kneaded. Accordingly, also in the second embodiment, as in the first embodiment, after the state of the viscosity of the paste S changed during standby (during the interruption period of the printing operation) is sufficiently recovered, the printing area E is recovered. Can be moved to. In particular, according to the printing apparatus of the second embodiment, as described above, since the paste S at the reference point P1 is once moved from the reference point P1 to the extension point P2, the paste S is kneaded during this time. Therefore, there is an advantage that the paste S can be kneaded more than the printing apparatus of the first embodiment.

  By the way, the printing apparatus demonstrated above is an illustration of preferable embodiment of the printing apparatus concerning this invention, The specific structure can be suitably changed in the range which does not deviate from the summary of this invention.

  For example, in each of the above-described embodiments, only one extension point P2 is set in the region on one side (the right side or the left side in FIG. 5 or the like) of the print region E, but a plurality of distances from the print region E are different from each other. The extension point P2 is set, and in the processing of steps S7 and S15, the longer the interruption period, the farther the paste S (squeegee 6a) is from the printing region E, according to the length of the interruption period of the printing work. You may make it move to the extension point P2. According to this configuration, as the interruption period is longer, the run-up section Er is expanded and the amount of paste S is kneaded, so that it is possible to suppress a difference in the state of the paste S depending on the length of the interruption period. It becomes.

  In this case, for example, the relationship between the suspension period (time) of the printing work or information about the period (for example, information that causes a suspension period such as “cleaning” or “waiting for board loading”) and the extension point P2 is as follows. A storage device that stores the determined table data is provided, and the control device 30 specifies the extension point P2 from the table data according to the interruption period (time) of the printing work, and paste S (squeegee 6a) at the extension point P2. ) May be moved. In particular, in the case of the second embodiment, a timing device such as a count-up timer that counts the elapsed time from the end of the previous printing operation is provided, and in the process of step S15, the control device 30 causes the timing device to After calculating the extension point P2 corresponding to the time measurement result each time, the paste S (squeegee 6a) may be moved to the extension point P2.

  Further, in the above-described embodiment, the case where the interruption period occurs in the printing operation due to the cleaning of the mask sheet 4 or the waiting of the subsequent substrate P is described. However, the cause of the interruption period is not limited thereto. .

  In each of the above embodiments, the present invention is applied to a type of printing apparatus that performs printing when the head 6 moves forward and when the head 6 moves backward by switching the posture of the squeegee 6a. However, according to the present invention, as described in a printing apparatus other than this type, for example, Patent Document 1 described in the background art, a pair of squeegees are reciprocated integrally along a mask sheet while moving forward. The present invention can also be applied to a type of printing apparatus that uses different squeegees at the time of return and return.

4 Mask sheet 6 Head 6a Squeegee 30 Controller E Printing area Er Run-up section P1 Reference point P2 Extension point

Claims (4)

A printing apparatus for printing a predetermined paste on a substrate,
A mask sheet provided with an opening for printing and overlaid on the substrate;
A squeegee for printing the paste on the substrate through the opening by moving the paste in a specific direction on the mask sheet;
The operation of the squeegee is performed so that the paste reciprocates between reference points set in areas outside the predetermined print area including the opening and outside the specific direction in the mask sheet. A control device for controlling,
The control device controls the squeegee so that the paste is located at a predetermined extension point outside the reference point at the end of the printing operation in a printing operation immediately before a predetermined interruption period occurs. together with the suspended period, the squeegee is stopped, in the first printing operation after the interruption period, before Kinobe length point moves the paste toward the printing region as the printing the paste A printing apparatus, wherein the squeegee is controlled to enter a region and perform printing on a substrate . The printing apparatus according to claim 1 ,
The control device sets the extension point at a position farther from the reference point and controls the squeegee based on the extension point as the interruption period is longer according to the length of the interruption period. Characteristic printing device. The printing apparatus according to claim 2 ,
A storage device for storing table data defining a relationship between the suspension period or information on the suspension period and the extension point;
The said control apparatus specifies the extension point corresponding to this from the said table data according to the said interruption period or the said information, The printing apparatus characterized by the above-mentioned. The printing apparatus according to any one of claims 1 to 3 ,
The printing apparatus according to claim 1, wherein the interruption period is a cleaning period of the mask sheet or a waiting period for loading a substrate to be processed.

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