Printing apparatus and printing method

Abstract

To determine whether a camera has gotten dirty or not.SOLUTION: A printing device, which prints a paste on a substrate using a mask having a predetermined opening formed, comprises: a substrate holding part that holds the substrate to align the substrate with the opening; a printing head that prints the paste on the substrate by filling the opening with the paste; a photographing part that photographs a back side of the mask in order to align the substrate; and a determining part that moves the photographing part to a stand-by position and determines whether the photographing part has gotten dirty, on the basis of an image photographed at the stand-by position.SELECTED DRAWING: Figure 2

Description

Technical Field

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[0001] The present disclosure relates to a printing apparatus and a printing method. <000000s>

Background Art

[0002] Patent Document 1 discloses a screen printing machine including a camera that images the back surface of a mask, an image processing determination unit that processes an image captured by the camera and determines solder contamination that has spread from the front surface of the mask to the back surface thereof, and a cleaning unit that cleans the back surface of the mask to remove the solder that has spread to the back surface of the mask when the solder contamination is greater than or equal to a predetermined value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As disclosed in Patent Document 1, solder may adhere to the back surface of the mask. Therefore, the solder adhering to the back surface of the mask may drip onto a camera located below the mask and stain the camera. When the camera is stained, the camera cannot correctly image the mask, and the alignment between the mask and the substrate cannot be correctly performed.

[0005] An object of the present disclosure is to provide a technique for determining whether a camera is stained.

Means for Solving the Problems

[0006] It should be noted that there may be some errors in the original text tags (such as <s and <00o0030>), and they are translated as they are. If these are incorrect in the original, they should be corrected before translation for a more accurate result.A printing apparatus according to one aspect of the present disclosure is a printing apparatus for printing paste onto a substrate using a mask having predetermined openings, comprising: a substrate holding unit for holding the substrate and aligning it with the openings; a print head for filling the openings with paste and printing the paste onto the substrate; an imaging unit for imaging the back surface of the mask for aligning the substrate; and a determination unit for moving the imaging unit to a standby position and determining whether the imaging unit is dirty based on the image captured at the standby position.

[0007] A printing method according to one aspect of the present disclosure is a printing method for printing paste onto a substrate using a mask having predetermined openings, wherein a substrate holding unit holds the substrate and aligns it with the openings, a print head fills the openings with paste and prints the paste onto the substrate, an imaging unit images the back surface of the mask for substrate alignment, and a determination unit moves the imaging unit to a standby position and determines whether the imaging unit is dirty based on the image captured at the standby position.

[0008] These comprehensive or specific embodiments may be implemented as systems, devices, methods, integrated circuits, computer programs, or recording media, or as any combination of systems, devices, methods, integrated circuits, computer programs, and recording media. [Effects of the Invention]

[0009] According to this disclosure, it is possible to determine whether or not the camera is dirty. [Brief explanation of the drawing]

[0010] [Figure 1] Plan view showing an example of the configuration of the printing apparatus according to this embodiment. [Figure 2] A side view showing an example of the printing apparatus according to this embodiment, where the camera unit is waiting in the camera standby position. [Figure 3] A side view showing an example of the printing apparatus according to this embodiment, where the camera unit is imaging the mask and the substrate. [Figure 4]Side view showing an example configuration of the camera unit according to this embodiment. [Figure 5] This figure shows a first example of an image captured at the camera standby position according to this embodiment. [Figure 6] A flowchart showing a first example of the camera dirt detection process according to this embodiment. [Figure 7] This figure shows a second example of an image captured at the camera standby position according to this embodiment. [Figure 8] A flowchart showing a second example of the camera dirt detection process according to this embodiment. [Figure 9] This figure shows an example of the configuration of the control system of the printing apparatus according to this embodiment. [Modes for carrying out the invention]

[0011] Embodiments of the present disclosure will be described in detail below, with appropriate reference to the drawings. However, unnecessary details may be omitted. For example, detailed explanations of already well-known matters and redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding by those skilled in the art. The accompanying drawings and the following explanation are provided to enable those skilled in the art to fully understand the present disclosure and are not intended to limit the subject matter of the claims.

[0012] (Embodiment) <Printing device configuration> First, an example of the configuration of the printing apparatus 1 according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a plan view showing an example of the configuration of the printing apparatus 1 according to this embodiment. Figure 2 is a side view showing an example of the printing apparatus 1 according to this embodiment when the camera unit 40 is waiting in the camera standby position. Figure 3 is a side view showing an example of the printing apparatus 1 according to this embodiment when the camera unit 40 is imaging the mask 3 and the substrate 2.

[0013] In this embodiment, for convenience of explanation, the conveyance direction of the substrate 2 is defined as the X direction, the direction orthogonal to the X direction in the horizontal plane is defined as the Y direction, and the direction perpendicular to the XY plane is defined as the Z direction. Also, for convenience of explanation, the positive direction of the X axis may be referred to as "right", the negative direction of the X axis as "left", the positive direction of the Y axis as "front", the negative direction of the Y axis as "rear", the positive direction of the Z axis as "up", and the negative direction of the Z axis as "down". Note that the expressions related to these directions are used for convenience of explanation and are not intended to limit the posture during actual use of the structure.

[0014] The printing apparatus 1 includes a mask frame 11, a substrate holding table 12, a substrate holding table moving mechanism 13, a printing unit 20, a printing unit moving mechanism 30, a camera unit 40, a camera unit moving mechanism 50, a mask cleaning unit 60, a mask cleaning unit moving mechanism 70, a blade cleaning unit 80, and a blade cleaning unit moving mechanism 100.

[0015] As shown in FIG. 1, the mask frame 11 is formed as a rectangular frame when viewed from above the printing apparatus 1. A flexible screen mask (hereinafter simply referred to as "mask") 3 is stretched on the mask frame 11. The mask 3 has a plurality of openings 4 corresponding to the shape and position of the electrodes to be printed on the substrate 2. Paste 5 is supplied onto the mask 3 by a paste supply mechanism (not shown). The paste 5 may be a solder paste containing solder particles. Alternatively, the paste 5 may be a conductive paste.

[0016] The substrate holding table 12 is located in the lower area of the mask 3 and holds (supports) the substrate 2 on its upper surface.

[0017] The substrate holding table moving mechanism 13 has a mechanism for freely moving the substrate holding table 12 in the X direction (refer to the arrow bx in FIG. 2), Y direction (refer to the arrow by in FIG. 2), Z direction (refer to the arrow bz in FIG. 2), and the rotational direction of the Z axis (refer to the arrow bθ in FIG. 2). The substrate holding table moving mechanism 13 moves the substrate holding table 12 in the XY direction so that the position of the electrode to be printed on the substrate 2 coincides with the position of the opening 4 of the mask 3. Then, the substrate holding table moving mechanism 13 moves (raises) the substrate holding table 12 in the Z direction to bring the upper surface (front surface) of the substrate 2 into contact with the lower surface (back surface) of the mask 3. Note that the substrate holding table 12 and the substrate holding table moving mechanism 13 may be collectively referred to as a substrate holding unit.

[0018] The printing unit 20 includes a squeegee 21 and a printing head 22. The squeegee 21 is a rectangular flat plate extending in the X direction, and the short side direction is inclined by a predetermined angle with respect to the surface of the mask 3. Two squeegees 21 are connected to the lower surface of the printing head 22. The printing head 22 has a function of raising and lowering the two squeegees 21 respectively (refer to the arrows a1, a2 in FIG. 2).

[0019] The printing unit moving mechanism 30 is connected to the printing head 22. The printing unit moving mechanism 30 has a mechanism for moving the printing head 22 in the Y direction (refer to the arrow ay in FIG. 1). For example, the printing unit moving mechanism 30 includes a Y-axis beam (not shown) for moving the printing head 22 in the Y direction.

[0020] The camera unit 40 includes an image sensor 41 and a prism 42. The camera unit 40 may be read as a camera or imaging unit. When the camera unit 40 is not imaging the substrate 2 and the mask 3, it waits in a predetermined camera standby position where the mask 3 is not above it, as shown in Figures 1 and 2. When the camera unit 40 is imaging the substrate 2 and the mask 3, it moves below the mask 3 (and / or above the substrate 2), as shown in Figure 3. The image sensor 41 images the top surface (front) of the substrate 2 and the bottom surface (back) of the mask 3 via the prism 42 and generates an image. The generated image is used to align the aperture 4 of the mask 3 with the electrodes to be printed on the substrate 2. Details of the configuration of the camera unit 40 will be described later (see Figure 4).

[0021] The camera unit movement mechanism 50 has a mechanism for freely moving the camera unit 40 in the X direction (see cx in Figures 1 and 2) and the Y direction (see cy in Figures 1 and 2). For example, as shown in Figure 1, the camera unit movement mechanism 50 is composed of an X-axis beam 51 and a Y-axis beam 52. The camera unit 40 is connected to the X-axis beam 51. The X-axis beam 51 is connected to the Y-axis beam 52. The control unit 200 (see Figure 9) controls the movement of the X-axis beam 51 along the Y-axis beam 52 and controls the movement of the camera unit 40 along the X-axis beam 51, thereby allowing the camera unit 40 to move freely in the XY direction. As shown in Figure 1, the printing apparatus 1 may have two rails 53 extending in the Y-axis direction at left and right positions on either side of the mask frame 11. The X-axis beam 51 may have two sliders 54 that can slide on the two rails 53. This allows the X-axis beam 51 to move smoothly in the Y direction along the two rails 53.

[0022] The mask cleaning unit 60 includes a blade 61, a blade holder 62, and a movable base 63. The blade 61 is a rectangular, flexible metal plate extending in the X direction, with its shorter side inclined at a predetermined angle to the surface of the mask 3. The blade 61 may be formed from an elastic material such as urethane rubber. The blade holder 62 holds multiple blades 61. The movable base 63 supports the blade holder 62. When the mask cleaning unit 60 is not performing mask cleaning, it waits in a predetermined waiting area located further forward than the front edge of the mask frame 11, as shown in Figure 2.

[0023] The mask cleaning unit 60 is connected to the mask cleaning unit moving mechanism 70. The mask cleaning unit moving mechanism 70 has a mechanism for moving the mask cleaning unit 60 in the Z direction (see arrow d1 in Figure 2) and the Y direction (see arrow dy in Figures 1 and 2).

[0024] The blade cleaning unit 80 is a unit for cleaning the blade 61.

[0025] The blade cleaning unit 80 is connected to the blade cleaning unit moving mechanism 100. The blade cleaning unit moving mechanism 100 includes an X-axis beam 105 that moves the blade cleaning unit 80 in the X direction (see arrow ex in Figure 1). When the blade cleaning unit 80 is not performing blade cleaning, it waits at a predetermined waiting location located at the right end of the waiting area for the mask cleaning unit 60, as shown in Figure 1. In other words, the blade cleaning unit moving mechanism 100 can move the blade cleaning unit 80 to a waiting position away from above the mask cleaning unit 60.

[0026] <Camera Unit Configuration> Next, the configuration of the camera unit 40 will be described with reference to Figure 4. Figure 4 is a side view showing an example of the configuration of the camera unit 40 according to this embodiment.

[0027] The camera unit 40 includes an image sensor 41, a prism 42, a lens 43, illumination 44, and a cover 45.

[0028] The image sensor 41 is, for example, a CMOS sensor or a CCD sensor. In this embodiment, the optical axis of the image sensor 41 is oriented in the positive direction of the Y-axis. The lens 43 is positioned on the optical axis (Y-axis) of the image sensor 41. The prism 42 is positioned on the optical axis (Y-axis) of the image sensor 41 and the lens 43.

[0029] When imaging the back surface of the mask 3, the prism 42 refracts light arriving from above (positive Z-axis direction) towards the lens 43 and image sensor 41 (negative Y-axis direction). This allows the image sensor 41 to image the back surface of the mask 3. When imaging the front surface of the substrate 2, the prism 42 refracts light arriving from below (negative Z-axis direction) towards the lens 43 and image sensor 41 (negative Y-axis direction). This allows the image sensor 41 to image the front surface of the substrate 2.

[0030] The illumination 44 includes an upper illumination 44A positioned above the prism 42 to illuminate the back surface of the mask 3, and a lower illumination 44B positioned below the prism 42 to illuminate the front surface of the substrate 2. The upper illumination 44A and the lower illumination 44B may each be composed of multiple LEDs.

[0031] The cover 45 is a light-transmitting plate and is positioned above the prism 42 and the upper illumination 44A. The cover 45 prevents paste that drips from the mask 3 from adhering to the upper illumination 44A and the prism 42.

[0032] The camera unit 40 captures images of the mask 3 and the substrate 2 with the image sensor 41 and generates an image. Based on the generated image, the control unit 200 (see Figure 9) calculates the amount of movement of the substrate holding table 12 so that the positions of the electrodes to be printed on the substrate 2 coincide with the positions of the openings 4 in the mask 3. Based on the calculated amount of movement, the control unit 200 controls the substrate holding table movement mechanism 13 to move the substrate holding table 12 in the XY direction. This ensures that the mask 3 and the substrate 2 are correctly aligned and that the paste 5 is applied to the correct electrode positions on the substrate 2.

[0033] However, as shown in Figure 3, when the camera unit 40 is positioned below the mask 3, paste 5 that has dripped from the mask 3 may adhere to the cover 45 or upper illumination 44A of the camera unit 40. In this case, the image sensor 41 cannot properly image the mask 3, and therefore the control unit 200 cannot correctly align the mask 3 and the substrate 2 using the image sensor 41. In this embodiment, a printing device 1 will be described that determines whether or not paste 5 is adhering to the cover 45 or upper illumination 44A of the camera unit 40, and if it is determined that paste 5 is adhering, displays information prompting cleaning of the camera unit 40. In the following description, the presence of paste 5 on the cover 45 or upper illumination 44A of the camera unit 40 may be expressed as "the camera is dirty." Also, the absence of paste 5 adhering to the cover 45 or upper illumination 44A of the camera unit 40 may be expressed as "the camera is not dirty."

[0034] <Example 1 of a method for detecting camera dirt> Figure 5 is a diagram showing a first example of an image captured at the camera standby position according to this embodiment. Figure 5(a) shows an example of an image captured when the camera is not dirty, and Figure 5(b) shows an example of an image captured when the camera is dirty. Figure 6 is a flowchart showing a first example of the camera dirt detection process according to this embodiment. Next, a first example of a camera dirt detection method for determining whether or not the camera is dirty will be described with reference to Figures 5 and 6.

[0035] When the control unit 200 determines whether the camera is dirty, it moves the camera unit 40 to the camera standby position shown in Figure 2 (S11). The determination of whether the camera is dirty may be performed at the start of production of a particular model or when a model is switched over. Alternatively, the determination of whether the camera is dirty may be performed when the circuit board 2 has been printed a predetermined number of times or more.

[0036] The camera dirt detection unit 204 (see Figure 9) increases the light intensity of the upper illumination 44A compared to when imaging the back surface of the mask 3 (for example, by setting the light intensity of the upper illumination 44A to maximum), and controls the image sensor 41 to capture an image (S12). The image thus captured is called a dirt detection image. As shown in Figure 2, the top plate 120 of the printing device is located above the camera unit 40, so if the camera is not dirty, the dirt detection image captured at the camera standby position will have many pixels that are darker and have lower brightness, as shown in Figure 5(a). On the other hand, if the camera is dirty, the dirt detection image captured at the camera standby position will have more pixels that are lighter and have higher brightness, as shown in Figure 5(b), compared to Figure 5(a).

[0037] The camera dirt detection unit 204 performs black and white binarization of the dirt detection image based on a predetermined threshold and generates a binarized image (S13). The threshold may be changed by the operator.

[0038] The camera dirt detection unit 204 calculates the proportion of white pixels in the binarized image (hereinafter referred to as the white pixel proportion) (S14).

[0039] The camera dirt detection unit 204 determines whether the percentage of white pixels is above a predetermined threshold (for example, 30%) (S15). This threshold may be changeable by the operator.

[0040] If the proportion of white pixels is below a predetermined threshold (S15: NO), the camera dirt detection unit 204 determines that the camera is not dirty (S16). As described above, the dirt detection image captured when the camera is not dirty has many dark pixels with low brightness. Therefore, if the proportion of white pixels in the binarized image is below the threshold, it is highly likely that the camera is not dirty. The process then ends.

[0041] If the proportion of white pixels is above a predetermined threshold (S15: YES), the camera dirt detection unit 204 determines that the camera is dirty and displays information prompting the camera unit 40 to be cleaned on the display unit 130 (see Figure 9) (S17). As described above, the dirt detection image taken when the camera is dirty has many bright, white pixels. Therefore, if the proportion of white pixels in the binarized image is above the threshold, there is a high possibility that the camera is dirty. The camera dirt detection unit 204 may, in addition to displaying information prompting the camera unit 40 to be cleaned on the display unit 130, output an audio prompting the camera unit 40 to be cleaned from a speaker (not shown) instead of displaying information prompting the camera unit 40 to be cleaned on the display unit 130.

[0042] Next, the control unit 200 stops the printing operation of the print head 22 (S18). Then, this process is completed. The control unit 200 does not need to restart the printing operation of the print head 22 until the operator cleans the camera unit 40. This is because, as described above, if dirt is attached to the camera unit 40, the alignment of the mask 3 and the substrate 2 cannot be performed correctly, resulting in the production of defective products.

[0043] In step S14, the camera dirt detection unit 204 may calculate the number of white pixels in the binarized image (hereinafter referred to as the number of white pixels). In this case, the camera dirt detection unit 204 may determine in step S15 whether the number of white pixels is above a predetermined threshold. If the number of white pixels is below the predetermined threshold (S15: NO), the camera dirt detection unit 204 may determine in step S16 that the camera is not dirty, and if the number of white pixels is above the predetermined threshold (S15: YES), the camera may determine in step S17 that the camera is dirty.

[0044] <Second example of a method for detecting camera dirt> Figure 7 shows a second example of an image captured at the camera standby position according to this embodiment. Figure 7(a) shows an example of a reference image, Figure 7(b) shows an example of an image captured when the camera is not dirty, and Figure 7(c) shows an example of an image captured when the camera is dirty. Figure 8 is a flowchart of a second example of the camera dirt detection process according to this embodiment. Next, a second example of a camera dirt detection method for determining whether or not the camera is dirty will be described with reference to Figures 7 and 8.

[0045] The image sensor 41 of the camera unit 40, in the camera standby position shown in Figure 2, and with the camera clean, pre-images a reference image as shown in Figure 7(a) and stores it in the storage unit 201 (see Figure 9). Since the camera is clean, the reference image has many pixels that are darker and have low brightness, as shown in Figure 7(a). The reference image may be pre-imaged before the printing device 1 is shipped and stored in the storage unit 201.

[0046] The control unit 200 then performs the same processing as in steps S11 to S12 in Figure 6 (S31 to S32). As a result, if the camera is not dirty, the dirt detection image captured at the camera standby position will have many pixels that are darker and have lower brightness, as shown in Figure 8(b). On the other hand, if the camera is dirty, the dirt detection image captured at the camera standby position will have many pixels that are lighter and have higher brightness, as shown in Figure 8(c), compared to Figure 8(b).

[0047] The camera dirt detection unit 204 compares the brightness of the reference image with the brightness of the dirt detection image. For example, the camera dirt detection unit 204 calculates the difference (hereinafter referred to as the brightness difference) between the average brightness of each pixel in the reference image and the average brightness of each pixel in the dirt detection image (S33).

[0048] The camera dirt detection unit 204 determines whether the difference in brightness is above a predetermined threshold (S34). This threshold may be changeable by the operator.

[0049] If the difference in brightness is less than a predetermined threshold (S34: NO), the camera dirt detection unit 204 determines that the camera is not dirty (S35). As described above, the dirt detection image captured when the camera is not dirty has many dark pixels with low brightness, as shown in Figure 7(b). Therefore, if the difference in brightness is less than the threshold, the brightness of the dirt detection image is close to the brightness of the reference image, and there is a high possibility that the camera is not dirty. Then the process returns to step S31.

[0050] If the difference in brightness is greater than or equal to a predetermined threshold (S34: YES), the camera dirt detection unit 204 determines that the camera is dirty and displays information prompting the camera unit 40 to be cleaned on the display unit 130 (see Figure 9) (S36). As described above, the dirt detection image captured when the camera is dirty has many bright, white pixels, as shown in Figure 7(c). Therefore, if the difference in brightness is greater than or equal to a threshold, the brightness of the dirt detection image deviates significantly from the brightness of the reference image, and there is a high possibility that the camera is dirty.

[0051] Next, the control unit 200 stops the printing operation of the print head 22 (S37). Then, this process ends. The control unit 200 does not need to restart the printing operation of the print head 22 until the operator cleans the camera unit 40.

[0052] <Control system configuration> Next, with reference to Figure 9, the configuration of the control system of the printing apparatus 1 according to this embodiment will be described. Figure 9 is a diagram showing an example of the configuration of the control system of the printing apparatus 1 according to this embodiment.

[0053] The control unit 200 of the printing device 1 is composed of a storage unit 201, a mechanism drive unit 202, a recognition processing unit 203, and a camera dirt detection unit 204.

[0054] The memory unit 201 stores data such as printing operation data used to print paste 5 onto the substrate 2, mask cleaning operation data used to clean the underside of the mask 3, and blade cleaning operation data used to clean the edges of the blade 61. If the second example of the dirt detection method described above is adopted, the memory unit 201 may also store a reference image.

[0055] The mechanism drive unit 202 is controlled by the control unit 200 to drive the substrate holding table moving mechanism 13, the printing unit moving mechanism 30, the print head 22, the camera unit moving mechanism 50, the mask cleaning unit moving mechanism 70, and the blade cleaning unit moving mechanism 100.

[0056] The recognition processing unit 203 analyzes the image captured by the image sensor 41 to recognize the position of the substrate 2 and the position of the mask 3, etc.

[0057] As described above, the camera dirt detection unit 204 determines whether or not the camera is dirty based on the dirt detection image (and reference image).

[0058] The display unit 130 is configured, for example, as a liquid crystal display and displays various information to inform the operator. For example, as described above, the display unit 130 displays information prompting the operator to clean the camera unit 40.

[0059] (Summary of this disclosure) The contents of this disclosure can be expressed as follows:

[0060] <Item 1> A printing apparatus (1) that prints paste (5) onto a substrate (2) using a mask (3) having predetermined openings formed therein comprises a substrate holding unit (e.g., a substrate holding table 12 and a substrate holding table moving mechanism 13), a printing head (22), an imaging unit (e.g., a camera unit 40), and a determination unit (e.g., a camera contamination determination unit 204). The substrate holder part holds the substrate and aligns it with the opening (4). The print head fills the opening with paste and prints the paste onto the substrate. The imaging unit images the back surface of the mask for substrate alignment. The determination unit moves the imaging unit to a standby position and determines whether the imaging unit is dirty based on the image captured in the standby position. This allows the printing device to determine whether or not the imaging unit is dirty based on the image captured in the standby position.

[0061] <Item 2> In the printing apparatus described in item 1, the imaging unit and the determination unit perform the following operations. The imaging unit captures a reference image in a standby position before the print head begins printing. The determination unit compares the image with a reference image to determine if there is any dirt on the imaging unit. This allows the printing device to determine whether or not the imaging unit is dirty by comparing the image captured in the standby position with a reference image.

[0062] <Item 3> In the printing apparatus described in item 2, the determination unit determines that there is dirt on the imaging unit if the difference in brightness between the reference image and the image captured is greater than or equal to a predetermined threshold. This allows the printing device to determine whether the imaging unit is dirty or not based on the difference in brightness between the image captured in the standby position and the reference image.

[0063] <Item 4> In the printing apparatus described in item 1, the determination unit determines whether each pixel of the image is being converted to black and white, and determines that there is dirt in the imaging unit if the number of pixels determined to be white is equal to or greater than a predetermined threshold. This allows the printing device to determine whether the imaging unit is dirty or not based on the number of white pixels in the binarized image obtained from the image captured in the standby position.

[0064] <Item 5> In the printing apparatus described in any one of items 1 to 4, the imaging unit has illumination (44). When the control unit 200 determines that the detection unit (for example, the camera dirt detection unit 204) is dirty on the imaging unit, it increases the light intensity of the illumination (44) compared to when imaging the back surface of the mask. As a result, dirt is captured as pixels that appear lighter in color, improving the accuracy of determining whether or not the imaging area is dirty.

[0065] <Item 6> The printing apparatus described in any one of items 1 to 5 further comprises a control unit (200). If the determination unit determines that there is dirt on the imaging unit, the control unit stops the printing operation of the print head (22). This prevents the printing process from being performed and resulting in defective products when there is dirt in the imaging area and the mask and substrate cannot be properly aligned.

[0066] <Item 7> The printing apparatus described in any one of items 1 to 6 further comprises a display unit (130). The display unit will display information regarding the contamination in the imaging unit if the determination unit determines that there is contamination in the imaging unit. This allows the operator to see information about the dirt on the imaging unit displayed on the screen and know that the imaging unit needs to be cleaned.

[0067] Furthermore, the contents described in items 1 to 7 above may also be expressed as printing methods.

[0068] While embodiments have been described above with reference to the attached drawings, this disclosure is not limited to such examples. It is clear to those skilled in the art that various modifications, alterations, substitutions, additions, deletions, and equivalents can be conceived within the scope of the claims, and these are also understood to fall within the technical scope of this disclosure. Furthermore, the components of the embodiments described above can be combined in any way without departing from the spirit of the invention. [Industrial applicability]

[0069] The technology disclosed herein is useful in the field of packaging, where paste is printed onto a substrate. [Explanation of Symbols]

[0070] 1 Printing device 2 circuit boards 3 Masks 4 aperture 5 Paste 11 Mask Frame 12. PCB holding table 13. Substrate holding table moving mechanism 20 printing units 21 Squeegee 22 print heads 30 Printing unit movement mechanism 40 Camera Units 41 Image sensor 42 Prisms 43 lenses 44 Lighting 44A upper lighting 44B Lower lighting 45 Cover 50 Camera unit movement mechanism 51 X-axis beam 52 Y-axis beam 53 rails 54 Sliders 60 Mask Cleaning Units 61 Blades 62 Blade holder 63 Mobile Base 70 Mask cleaning unit moving mechanism 80 Blade Cleaning Unit 100 Blade cleaning unit moving mechanism 105 X-axis beam 120 Top plate 130 Display section 200 Control Unit 201 Storage section 202 Mechanism Drive Unit 203 Recognition Processing Unit 204 Camera dirt detection section

Claims

1. A printing apparatus for printing paste onto a substrate using a mask in which predetermined openings are formed, A substrate holding portion that holds the substrate and aligns it with the opening, A print head that fills the opening with paste and prints the paste onto the substrate, For the purpose of aligning the substrate, an imaging unit is provided to image the back surface of the mask, The system includes a determination unit that moves the imaging unit to a standby position and determines whether the imaging unit is dirty based on the image captured in the standby position. Printing device.

2. A printing apparatus according to claim 1, The imaging unit captures a reference image at the standby position before the print head performs printing. The determination unit compares the reference image with the image to determine whether the imaging unit is dirty. Printing device.

3. A printing apparatus according to claim 2, The determination unit determines that there is dirt in the imaging unit if the difference in brightness between the reference image and the image is greater than or equal to a predetermined threshold. Printing device.

4. A printing apparatus according to claim 1, The determination unit performs a black and white binarization determination for each pixel of the image, and determines that there is dirt in the imaging unit if the number of pixels determined to be white is equal to or greater than a predetermined threshold. Printing device.

5. A printing apparatus according to any one of claims 1 to 4, The imaging unit has illumination, and when the determination unit determines that the imaging unit is dirty, the amount of light from the illumination is increased compared to when imaging the back surface of the mask. Printing device.

6. A printing apparatus according to any one of claims 1 to 4, The control unit has a mechanism that stops the printing operation of the print head when the determination unit determines that there is dirt on the imaging unit. Printing device.

7. A printing apparatus according to any one of claims 1 to 4, If the determination unit determines that there is dirt on the imaging unit, the system has a display unit that displays information regarding the dirt on the imaging unit. Printing device.

8. A printing method for printing paste onto a substrate using a mask in which predetermined openings are formed, The substrate holding part holds the substrate and aligns it with the opening. The print head fills the opening with paste and prints the paste onto the substrate. The imaging unit images the back surface of the mask in order to align the substrate. The determination unit moves the imaging unit to a standby position and determines whether the imaging unit is dirty based on the image captured at the standby position. Printing method.

9. The printing method according to claim 8, The imaging unit captures a reference image at the standby position before the print head performs printing. The determination unit compares the reference image with the image to determine whether the imaging unit is dirty. Printing method.

10. The printing method according to claim 9, The determination unit determines that there is dirt in the imaging unit if the difference in brightness between the reference image and the image is greater than or equal to a predetermined threshold. Printing method.

11. The printing method according to claim 8, The determination unit performs a black and white binarization determination for each pixel of the image, and determines that there is dirt in the imaging unit if the number of pixels determined to be white is equal to or greater than a predetermined threshold. Printing method.

12. A printing method according to any one of claims 8 to 11, The imaging unit has illumination, and when the determination unit determines that the imaging unit is dirty, the amount of light from the illumination is increased compared to when imaging the back surface of the mask. Printing method.

13. A printing method according to any one of claims 8 to 11, If the determination unit determines that there is dirt on the imaging unit, the control unit stops the printing operation of the print head. Printing method.

14. A printing method according to any one of claims 8 to 11, The display unit displays information regarding the contamination of the imaging unit when the determination unit determines that there is contamination in the imaging unit. Printing method.

Images