JP2019093664A - Printing machine and print head - Google Patents

Abstract

To equip a printing pressure sensor S and a load reduction spring 71 while suppressing increase in size of a print head 6.SOLUTION: In a printing machine, a printing pressure sensor S is disposed inside (in other word 'insertion') of a spiral-shape load reduction spring 71, as such, the printing pressure sensor S is disposed while an inside space of the load reduction spring 71 is effectively utilized, thereby capable of equipping the printing pressure sensor S and the load reduction spring 71 while suppressing increase in size of a print head 6.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a printing technique in which printing is performed by sliding a squeegee on a mask while applying printing pressure to the squeegee.

  Conventionally, there is known a printing machine which prints a paste supplied on the upper surface of a mask on a print object by sliding a squeegee on the upper surface of the mask while making the print object face the lower surface of the mask. In order to perform such printing well, it is important to apply an appropriate printing pressure to the squeegee. Then, the printing machine described in patent document 1 is equipped with the strain gauge attached to the squeegee holder holding a squeegee, and performs printing, controlling the printing pressure given to the squeegee based on the output value of a strain gauge.

Japanese Patent Application Publication No. 09-174808

  By the way, in order to suppress an impact at the moment when the squeegee abuts on the mask, the print head provided with the squeegee as described above may be provided with a load reducing spring for urging the squeegee upward. However, the increase in the size of the print head has been a problem with an increase in the number of parts such as a pressure sensor such as a strain gauge and a load reducing spring.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a technology that enables the installation of a pressure sensor and a load reducing spring while suppressing an increase in size of a print head.

  The printing machine according to the present invention includes a pressure sensor for outputting a detected value according to the applied pressure, a squeegee disposed below the pressure sensor and connected to the pressure sensor, and the squeegee from above via the pressure sensor A print head having a printing pressure application part that applies printing pressure, a load reduction spring that has a spiral-shaped load reduction spring and that biases the squeegee upward by the load reduction spring, and a print object facing from above The printing object is printed by sliding a squeegee of the print head on the upper surface of the mask, and at least a part of the pressure sensor is an inner side of a load reducing spring. Is located in

  The print head according to the present invention includes a pressure sensor that outputs a detection value according to the applied pressure, a squeegee disposed below the pressure sensor and connected to the pressure sensor, and the squeegee from above via the pressure sensor The pressure sensor includes a printing pressure applying portion for applying a printing pressure, and a load reducing portion having a spiral load reducing spring and urging the squeegee upward by the load reducing spring, and at least a part of the pressure sensor is an inner side of the load reducing spring. Is located in

  In the present invention (printer, print head) configured as described above, the pressure sensor is disposed (in other words, inserted) inside the spiral load reducing spring. As described above, since the pressure sensor is disposed by effectively utilizing the space inside the load reducing spring, it becomes possible to equip the pressure sensor and the load reducing spring while suppressing an increase in size of the print head. ing.

  Also, the load reducing portion has a flange fixed to the pressure sensor above the load reducing spring, and the load reducing spring presses the flange upward to bias the squeegee upward via the pressure sensor. , And may constitute a printing press. In such a configuration, it is possible to accurately reflect the reduction of the load by the load reduction spring on the pressure sensor.

  The printing pressure application unit has a printing pressure spring disposed above the flange, and the printing press is configured to apply printing pressure to the squeegee by pressing the flange downward with the printing pressure spring. Also good. Such a configuration shares the flange provided for load reduction of the squeegee with the load reducing spring for applying the printing pressure of the squeegee with the printing pressure spring, and effectively contributes to suppressing the enlargement of the print head.

  In addition, the printing machine may be configured such that a plurality of units configured by the pressure sensor, the print application unit, and the load reduction unit are provided on the print head. That is, in the present invention, since the pressure sensor is disposed by effectively using the space inside the load reducing spring, the pressure sensor, the print application unit, and the load reducing unit are configured while suppressing an increase in size of the print head. It is possible to provide a plurality of units to be

  In addition, the printing press may be configured to further include a printing pressure information acquisition unit that acquires information on printing pressure given to the squeegee based on detection values of pressure sensors of each of the plurality of units. In such a configuration, it is possible to accurately acquire information related to printing based on detection values of a plurality of pressure sensors.

  In addition, the printing pressure information acquisition unit may configure the printing press so as to acquire the difference between the detection values of the pressure sensors of each of the plurality of units as information indicating the bias of the printing pressure given to the squeegee. In this configuration, the bias of the printing pressure can be accurately obtained based on the detection values of the plurality of pressure sensors.

  In addition, the printing information acquisition unit may configure the printing machine so as to warn the operator if the difference between the maximum value and the minimum value of the detection values of the pressure sensors in each of the plurality of units is equal to or greater than a threshold. In this configuration, when the deviation of the printing pressure is large, the operator can be warned to urge the necessary work.

  The printing pressure information acquisition unit may configure the printing machine to measure the printing pressure applied to the squeegee based on the average value of the detection values of the pressure sensors of each of the plurality of units. In such a configuration, the printing pressure can be measured while suppressing the influence of external noise mixed in the detection value of the pressure sensor.

  There are various types of sensors that can be used as pressure sensors. Therefore, the pressure sensor may be a magnetostrictive sensor.

  According to the present invention, it is possible to equip a pressure sensor and a load reducing spring while suppressing an increase in size of the print head.

FIG. 1 is a front view schematically showing a printing machine to which the present invention is applied. FIG. 2 is a block diagram showing an electrical configuration of the printing press of FIG. 1. FIG. 2 is a perspective view partially showing the configuration of a print head. FIG. 2 is a front view partially showing the configuration of a print head. FIG. 2 is a side view partially showing the configuration of a print head. Sectional drawing on the AA line which shows the structure of a printing head partially. FIG. 3 is a cross-sectional view taken along the line A-A showing a configuration of a printing pressure sensor provided in the printing head.

  FIG. 1 is a front view schematically showing a printing machine to which the present invention is applied. FIG. 2 is a block diagram showing an electrical configuration of the printing machine shown in FIG. In FIG. 1 and the following drawings, XYZ orthogonal coordinate axes are shown where the Z direction is a vertical direction and the X direction and the Y direction are horizontal directions. The printing press 1 includes a mask holding unit 2 for holding a mask M, a substrate holding unit 4 disposed below the mask M, and a print head 6 disposed above the mask M. Furthermore, the printing press 1 includes a main control unit 10 including a central processing unit (CPU), a random access memory (RAM), and the like. Then, the main control unit 10 controls the substrate holding unit 4 and the print head 6 so that the substrate holding unit 4 causes the substrate B to face the mask M from below while the tip of the squeegee 61 of the squeegee unit 6 is the upper surface of the mask M Slide in the X direction. As a result, the paste (solder) supplied to the upper surface of the mask M is printed on the upper surface of the substrate B through the pattern holes penetrating the mask M. Furthermore, the printing press 1 includes a display unit 11 configured of, for example, a liquid crystal display. Therefore, the operator can confirm the operation status of the printing press 1 by confirming the display content of the display unit 11.

  The mask holding unit 2 has a clamp member 21 and the mask M is detachably attached to the clamp member 21 through a frame F provided at the peripheral edge thereof. Thus, the mask M having a flat plate shape is horizontally held by the mask holding unit 2. The mask M has a rectangular shape in a plan view, and has through holes (pattern holes) having a shape corresponding to the print pattern on the substrate B.

  The substrate holding unit 4 is disposed below the mask M held by the mask holding unit 2 and has a function of aligning the position of the substrate B with the mask M. The substrate holding unit 4 includes a pair of conveyors 41 for conveying the substrate B, a substrate holding unit 42 for holding the substrate B received from the conveyor 41, and a flat movable table 43 for supporting the conveyor 41 and the substrate holding unit 42. And.

  The pair of conveyors 41 are disposed in parallel to the Y direction with a space in the X direction, and support the both ends of the substrate B in the X direction from below at the respective upper surfaces. And each conveyor 41 conveys the board | substrate B to a Y direction, and performs loading or unloading of the board | substrate B with respect to the printing machine 1. FIG.

  The substrate holding unit 42 has a flat lift table 421 and a slide support 422 slidable in the Z direction with respect to the movable table 43. The lift table 421 is supported by the upper end of the slide support 422. Further, on the top surface of the lift table 421, a plurality of backup pins 423 erected in the Z direction are arranged at intervals in the X direction and the Y direction. Then, as the slide support 422 moves up and down, the backup pin 423 moves up and down together with the lift table 421. For example, when the substrate B of the conveyor 41 is carried in, the upper end of each backup pin 423 is located below the upper surface of the conveyor 41. Then, when the conveyor 41 carries the substrate B directly above the backup pins 423, the backup pins 423 ascend and the upper end of the backup pins 423 protrudes upward from the upper surface of the conveyor 41. As a result, the substrate B is delivered from the upper surface of the conveyor 41 to the upper end of each backup pin 423.

  Further, the substrate holding unit 42 has a pair of clamp plates 424 arranged at intervals above the pair of conveyors 41 in the X direction, and at least one of the clamp plates 424 is movable in the X direction. The upper surface of each clamp plate 424 is a plane parallel to the X direction and the Y direction, and is located at the same height as each other. When the substrate B on the backup pins 423 ascends between the pair of clamp plates 424, the distance between the clamp plates 424 narrows, and the substrate B is clamped from the X direction (horizontal direction) by the clamp plates 424.

  Furthermore, the substrate holding unit 4 has a table drive mechanism 44 that drives the movable table 43. The table drive mechanism 44 includes an X-axis table 441, a Y-axis table 442 attached to the upper surface of the X-axis table 441, an R-axis table 443 attached to the upper surface of the Y-axis table 442, and an R-axis table 443. And a ball screw 444 for moving the movable table 43 up and down. Therefore, the table drive mechanism 44 positions the loaded substrate B with respect to the mask M by driving the conveyor 41 and the substrate holding unit 42 disposed on the movable table 43 in the X, Y, Z, R directions. be able to. Thereby, the upper surfaces of the clamp plate 424 and the substrate B are in contact with the lower surface of the mask M.

  Further, as shown in FIG. 2, the printing press 1 has a head drive unit 6D having an X-axis motor Mx for driving the print head 6 in the X direction and a Z-axis motor Mz for driving the print head 6 in the Z direction. Have. Then, the main control unit 10 drives the print head 6 in the X direction by the X-axis motor Mx while pressing the squeegee 61 of the print head 6 against the upper surface of the mask M with a predetermined printing pressure by the Z-axis motor Mz. , Squeegee 61 is trained on the upper surface of the mask M.

  Subsequently, the details of the print head 6 will be described with reference to FIGS. Here, FIG. 3 is a perspective view partially showing the configuration of the print head, FIG. 4 is a front view partially showing the configuration of the print head, and FIG. 5 is a side view partially showing the configuration of the print head FIG. 6 is a cross-sectional view taken along the line A-A partially showing the configuration of the print head, and FIG. 7 is a cross-sectional view taken along the line A-A showing the configuration of the printing pressure sensor included in the print head.

  The print head 6 has a support bracket 62 that rotatably supports the squeegee 61 about an axis parallel to the Y direction, and a rotation motor Mθ attached to the support bracket 62 (FIG. 1). The turning motor Mθ is connected to the turning shaft of the squeegee 61, and the angle (attack angle) at which the squeegee 61 contacts the upper surface of the mask M can be adjusted by turning the squeegee 61 with the turning motor Mθ. it can.

  The print head 6 also has a support frame 63 above the support bracket 62 for supporting the support bracket 62 to which the squeegee 61 is attached. That is, the print head 6 has two support rods 64 extending in parallel in the Z direction, and each support rod 64 is provided slidably in the Z direction with respect to the support frame 63. A rod guide 631 having an insertion hole 632 extending in the Z direction is attached to the support frame 63 correspondingly to each support rod 64, and the two support rods 64 are inserted from above into the insertion holes 632 of the corresponding rod guides 631. It is done. Each support rod 64 has a flange 641 having a larger diameter than the insertion hole 632 at its upper end, and the flange 641 is hooked on the rod guide 631 from above so that the support rod 64 does not fall off the rod guide 631 It is done. On the other hand, the lower ends of the two support rods 64 are attached to the upper surface of a plate 65 attached to the upper end of the support bracket 62.

  Furthermore, the print head 6 has a load reducing unit 7 that biases the squeegee 61 upward. In the present embodiment, the two load reducing portions 7 are provided between the two support rods 64, but the configuration of these load reducing portions 7 is the same except for the mechanism related to printing pressure detection described in detail later. is there. Therefore, here, the details of one load reducing unit 7 will be described, and the configuration common to the two load reducing units 7 will be denoted by the corresponding reference numerals, and the description thereof will be omitted.

  The load reducing portion 7 has a load reducing spring 71 which has a helical shape and can be expanded and contracted in the Z direction, and a support ring 72 which supports the load reducing spring 71. The load reducing spring 71 is inserted from above into the through hole 633 penetrating the support frame 63 in the Z direction, and the upper end of the load reducing spring 71 protrudes upward from the upper surface of the support frame 63. The support ring 72 faces the through hole 633 from the lower side, and is fixed to the lower surface of the support frame 63 by screws. The support ring 72 supports the load reducing spring 71 from below with respect to the support frame 63.

  Further, the load reducing portion 7 has a rod 73 inserted from the lower side inside the load reducing spring 71 through the hole of the support ring 72 and a flange 74 disposed above the load reducing spring 71. The lower end of the rod 73 is fixed to the upper surface of the plate 65, and the rod 73 is erected from the plate 65 upward in parallel in the Z direction. The flange 74 is fixed to the upper end of a rod 73 protruding upward from the load reducing spring 71 and protrudes laterally (horizontally) from the rod 73. The lower end of the load reducing spring 71 is in contact with the support ring 72, and the upper end of the load reducing spring 71 is in contact with the flange 74. The load reducing spring 71 is sandwiched by the support ring 72 and the flange 74 in the Z direction. Is compressed. Therefore, the elastic force of the load relief spring 71 pressing the flange 74 upward is transmitted to the plate 65 via the rod 73 to bias the squeegee 6 attached to the plate 65 upward.

  The print head 6 also has a printing pressure application unit 8 that applies printing pressure to the squeegee 61 by pressing the squeegee 61 downward. In the present embodiment, two printing pressure application units 8 are provided, but the configuration of these printing pressure application units 8 is the same. Therefore, the details of one printing pressure application unit 8 will be described here, and the configuration common to the two printing pressure application units 8 will be denoted by the corresponding reference numerals, and the description thereof will be omitted.

  The impression pressure applying portion 8 has an impression spring 81 which has a helical shape and can be expanded and contracted in the Z direction, and a cover member 82 having a cylindrical shape. The pressure spring 81 is disposed above the flange 74 of the load reducing unit 7 and is provided coaxially with the load reducing spring 71. The cover member 82 has a hollow portion 821 which opens downward and has a cylindrical shape inside, and is externally fitted from above onto the impression pressure spring 81 and the flange 74 and fixed to the support frame 63. Thus, the impression spring 81 and the flange 74 are inserted into the hollow portion 821 of the cover member 82 from below. The lower end of the impression spring 81 contacts the flange 74, the upper end of the impression spring 81 contacts the inner wall of the upper end of the cover member 82, and the impression spring 81 is sandwiched by the flange 74 and the cover member 82 in the Z direction. Is compressed. Therefore, the elastic force of the impression spring 81 pressing the flange 74 downward is transmitted to the plate 65 via the rod 73 to press the squeegee 61 attached to the plate 65 against the mask M.

  The support frame 63 is driven in the Z direction by the Z-axis motor Mz. Therefore, when the support frame 63 is driven downward from the state where the squeegee 61 contacts the mask M, the cover member 82 is also moved downward along with the support frame 63, and the printing spring 81 is shortened. As a result, the elastic force of the printing pressure spring 81 is increased, and the printing pressure generated between the squeegee 61 and the mask M is also increased. That is, the printing pressure spring 81 applies a printing pressure corresponding to the height of the support frame 63 to the squeegee 61.

  Furthermore, the print head 6 has a mechanism for measuring the printing pressure applied to the squeegee 61. That is, one of the two rods 73 (the rod 73 in FIG. 3 and the right in FIG. 6) is a sensor rod Sr formed of a magnetostrictive body, and the permeability changes in accordance with the applied pressure Have physical properties. The sensor rod Sr may be formed by forming the entire sensor rod Sr with a magnetostrictive body, or, for example, by forming a thin film of a magnetostrictive body by plating on the entire peripheral surface of a metal core. It may be done.

  A coil Sc is wound around the outer periphery of the sensor rod Sr. As shown in detail in FIG. 7, the printing pressure sensor S has a resin bobbin Sb fitted on the outside of the sensor rod Sr, and the coil Sc is wound in a recess provided on the outer periphery of the bobbin Sb. . Furthermore, the printing pressure sensor S has a metal shield Ss fitted to the outside of the bobbin Sb, and shields external noise by the shield Ss. In the Z direction, the sensor rod Sr (in other words, the arrangement range of the magnetostrictive body) is longer than the coil Sc, and both ends of the sensor rod Sr protrude from both ends of the coil Sc.

  Thus, the printing pressure sensor S is configured by the sensor rod Sr, the coil Sc, and the like, and the upper end portion of the printing pressure sensor S is inserted inside the load reducing spring 71. In the printing pressure sensor S, an impedance corresponding to the pressure applied to the sensor rod Sr is generated in the coil Sc.

  The print head 6 further includes a circuit board C and a wire W electrically connecting the circuit board C and the printing pressure sensor S, and the circuit board C has a coil Sc of the printing pressure sensor S via the wire W. When the current is supplied to the printing pressure sensor S, the printing pressure sensor S outputs a voltage according to the impedance of the coil Sc. Then, the circuit board C transmits the voltage output from the printing pressure sensor S to the main control unit 10 as a detection value of the printing pressure sensor S. Therefore, the main control unit 10 can measure the printing pressure applied to the squeegee 61 based on the detection value of the printing pressure sensor S received from the circuit board C. The circuit board C is attached to one of the two support rods 64 that is closer to the printing pressure sensor S.

  In the embodiment configured as described above, the printing pressure sensor S is disposed (in other words, inserted) inside the load reducing spring 71 having a spiral shape. As described above, since the printing pressure sensor S is disposed by effectively utilizing the space inside the load reducing spring 71, the printing pressure sensor S and the load reducing spring 71 can be used while suppressing an increase in size of the print head 6. It is possible to equip it.

  Further, the load reducing unit 7 has a flange 74 fixed to the sensor rod Sr of the printing pressure sensor S above the load reducing spring 71, and the printing pressure sensor is pressed by the load reducing spring 71 pressing the flange 74 upward. The squeegee 61 is urged upward through the sensor rod Sr of S. In such a configuration, the reduction of the load by the load reduction spring 71 can be accurately reflected on the printing pressure sensor S.

  Further, the printing pressure application unit 8 has a printing pressure spring 81 disposed above the flange 74, and presses the flange 74 downward by the printing pressure spring 81 to apply printing pressure to the squeegee 61. In this configuration, the flange 74 provided for reducing the load of the squeegee 61 by the load reducing spring 71 is shared with the application of the printing pressure of the squeegee 61 by the printing pressure spring 81, and the enlargement of the print head 6 is suppressed. Contributing effectively.

  As described above, in the present embodiment, the printing press 1 corresponds to an example of the “printing press” of the present invention, the print head 6 corresponds to an example of the “print head” of the present invention, and the printing pressure sensor S corresponds to the example of the present invention. The squeegee 61 corresponds to an example of the “squeegee” of the present invention, and the printing pressure applying unit 8 corresponds to an example of the “printing pressure applying unit” of the present invention. The load reducing portion 7 corresponds to an example of the “load reducing portion” of the present invention, the load reducing spring 71 corresponds to an example of the “load reducing spring” of the present invention, and the mask holding unit 2 corresponds to the “mask holding of the present invention The flange 74 corresponds to an example of the “flange” of the present invention, the impression spring 81 corresponds to an example of the “impression spring” of the present invention, and the impression pressure sensor S is applied with impression pressure The sensor unit U (FIG. 6) composed of the portion 8 and the load reducing portion 7 is the present invention It corresponds to an example of "units".

  The present invention is not limited to the above-described embodiment, and various modifications can be made to the above-described one without departing from the scope of the invention. For example, the number of sensor units U is not limited to one, and a plurality of sensor units U can be provided on the print head 6. That is, in the present invention, since the printing pressure sensor S is disposed by effectively utilizing the space inside the load reducing spring 71, a plurality of sensor units U can be provided while suppressing an increase in size of the print head 6. It is possible.

  Further, when the plurality of sensor units U are provided in the print head 6 as described above, the main control unit 10 (printing pressure information acquisition unit) determines the squeegee based on the detection value of the printing pressure sensor S of each of the plurality of sensor units U Information on printing pressure given to 61 can be obtained. That is, based on the detection values of the plurality of printing pressure sensors S, the information can be accurately acquired. Specifically, the main control unit 10 can execute the control shown in each of the following control examples.

First Control Example In the first control example, the main control unit 10 obtains the difference between the detection values of the plurality of printing pressure sensors S as information indicating the bias of the printing pressure given to the squeegee 61, in other words, the information indicating the biased load Do. Specifically, the main control unit 10 determines whether the difference between the maximum value and the minimum value of the detection values of the plurality of printing pressure sensors S is equal to or more than a threshold. Then, when the difference is equal to or more than the threshold value, the main control unit 10 displays on the display unit 11 a warning to the operator that the unbalanced load is excessive. In this control example, when the deviation of the printing pressure is large, the operator can be warned to prompt the necessary work.

Second Control Example In the second control example, the main control unit 10 calculates an average value of detection values of a plurality of printing pressure sensors S as printing pressure given to the squeegee 61. In such a configuration, the printing pressure can be calculated (measured) while suppressing the influence of external noise mixed in the detection value of the printing pressure sensor S.

Besides, it is of course possible to add a modification different from the control example mentioned here to the above embodiment. For example, based on the result of acquiring the information indicating the bias of the printing pressure given to the squeegee 61, feedback control may be performed on the printing pressure applied to the squeegee 61 so as to eliminate the bias.

  Further, the type of sensor that can be used as the printing pressure sensor S is not limited to the magnetostrictive sensor. That is, the sensor rod Sr made of a material (for example, a piezoelectric body) whose physical property changes with respect to the applied pressure, and the detection element (the coil Sc in the above example) which detects the change of the physical property of the sensor rod Sr. The printing pressure sensor S can be configured.

1 ... printing machine 2 ... mask holding unit (mask holding unit)
Reference Signs List 6 print head 61 squeegee 7 load reducing portion 71 load reducing spring 74 flange 8 impression pressure applying portion 81 impression pressure spring S impression pressure sensor (pressure sensor, magnetostrictive sensor)
U: Sensor unit (unit)

Claims (10)

A pressure sensor for outputting a detected value corresponding to the applied pressure, a squeegee disposed below the pressure sensor and connected to the pressure sensor, and applying a pressure from above to the squeegee via the pressure sensor A print head having a printing pressure applying portion, and a load reducing portion having a helical load reducing spring and urging the squeegee upward by the load reducing spring;
And a mask holding unit that holds the mask by facing the print object from above.
Printing is performed on the print target by sliding the squeegee of the print head on the upper surface of the mask;
In the printing head, at least a part of the pressure sensor is disposed inside the load reducing spring.   The load reducing portion has a flange fixed to the pressure sensor above the load reducing spring, and the load reducing spring presses the flange upward to move the squeegee upward via the pressure sensor. The printing press according to claim 1, wherein the printing press is biased.   The printing pressure application unit includes a printing pressure spring disposed above the flange, and applies a printing pressure to the squeegee by pressing the flange downward by the printing pressure spring. Printer.   The printing machine according to any one of claims 1 to 3, wherein a plurality of units configured by the pressure sensor, the printing application unit, and the load reducing unit are provided on the printing head.   The printing press according to claim 4, further comprising a printing pressure information acquisition unit that acquires information related to printing pressure given to the squeegee based on detection values of the pressure sensor of each of the plurality of units.   The printing press according to claim 5, wherein the printing pressure information acquisition unit acquires a difference between detection values of the pressure sensors of the plurality of units as information indicating deviation of printing pressure applied to the squeegee.   The printing machine according to claim 6, wherein the print information acquisition unit determines to warn an operator when the difference between the maximum value and the minimum value of the detection values of the pressure sensors of the plurality of units is equal to or greater than a threshold. .   The printing according to any one of claims 5 to 7, wherein the printing pressure information acquisition unit measures the printing pressure applied to the squeegee based on an average value of detection values of the pressure sensor of each of the plurality of units. Machine.   The printing press according to any one of claims 1 to 8, wherein the pressure sensor is a magnetostrictive sensor. A pressure sensor that outputs a detected value according to the applied pressure;
A squeegee disposed below the pressure sensor and connected to the pressure sensor;
A printing pressure application unit that applies a printing pressure to the squeegee from above via the pressure sensor;
A load relief spring having a spiral shape and having a load relief portion for urging the squeegee upward by the load relief spring;
A print head in which at least a portion of the pressure sensor is disposed inside the load relief spring.

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