Rotary screen printing apparatus

Abstract

To provide a rotary screen printing apparatus which can perform screen printing with high quality.SOLUTION: A rotary screen printing apparatus has: a screen printing plate which is rotatable in a first rotation direction around a first drawing axis; an impression cylinder which is so located as to contact the screen printing plate via a printed matter transported along a prescribed flow, and is rotatable in a second rotation direction opposite to the first rotation direction around a second drawing axis parallel to the first drawing axis; a squeegee which extrudes an ink onto the printed matter via the screen printing plate; and a roller which is located on a downstream side of flow of the printed matter with respect to the impression cylinder. The roller functions so as to delay separation of the printed matter from the screen printing plate.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a rotary screen printing apparatus that performs printing while rotating a cylindrical screen plate. [Background technology]

[0002] A rotary screen printing apparatus has been known as one type of screen printing apparatus (see Patent Documents 1 and 2). A rotary screen printing apparatus is a printing apparatus that performs printing by rotating a cylindrical screen plate and bringing it into contact with a printing object.

[0003] Rotary screen printing machines are capable of high-speed printing, and are therefore often used when a large number of printed materials need to be produced in a short period of time. They can also print a single design by rotating the screen multiple times, and are sometimes used to print long, continuous designs. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-183709 A [Patent Document 2] JP 2011-51316 A Summary of the Invention [Problem to be solved by the invention]

[0005] In printing methods using rotary screen printing machines, it is known that the action of the substrate separating from the screen, known as "plate separation," has a significant effect on print quality. For example, if the substrate remains in contact with the screen for a long period of time, problems such as bleeding of the ink transferred to the substrate or displacement of the image from the specified position are likely to occur.

[0006] Therefore, in the conventional rotary screen printing apparatus, it has been recommended to configure the printing medium so that "plate release" occurs immediately after the printing material comes into contact with the screen.

[0007] However, the inventors have found that even when using a rotary screen printing apparatus in which "plate release" is controlled, problems with print quality often occur.

[0008] The present invention has been made in view of the above background, and an object of the present invention is to provide a rotary screen printing apparatus that is capable of performing screen printing of higher quality. [Means for solving the problem]

[0009] In the present invention, 1. A rotary screen printing apparatus comprising: a screen plate rotatable in a first rotation direction about a first stretching axis; an impression cylinder arranged to come into contact with the screen plate via a printing medium transported along a predetermined flow, and rotatable in a second rotation direction opposite to the first rotation direction about a second stretching axis parallel to the first stretching axis; a squeegee that pushes ink onto the substrate through the screen; A roller disposed downstream of the flow of the printing medium from the impression cylinder; having A rotary screen printing apparatus is provided, wherein the roller functions to retard the release of the substrate from the screen. Effect of the Invention

[0010] The present invention can provide a rotary screen printing apparatus that enables higher quality screen printing. [Brief description of the drawings]

[0011] [Figure 1]FIG. 1 is a cross-sectional view showing a schematic configuration of a main part of a conventional rotary screen printing device. [Diagram 2] 1 is a cross-sectional view showing a schematic configuration of a main part of a rotary screen printing apparatus according to an embodiment of the present invention. [Diagram 3] FIG. 4 is a cross-sectional view showing a schematic configuration of a main part of a rotary screen printing apparatus according to another embodiment of the present invention. [Figure 4] FIG. 11 is a cross-sectional view showing a schematic configuration of a main part of a rotary screen printing apparatus according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] In order to better understand the features of the present invention, a brief description will first be given of the structure and operation of a conventional rotary screen printing apparatus.

[0014] (Conventional rotary screen printing device) FIG. 1 shows a schematic cross section of the main part of a conventional rotary screen printing apparatus.

[0015] As shown in FIG. 1, a conventional rotary screen printing apparatus 1 has a screen plate 10 and an impression cylinder 20.

[0016] The screen plate 10 has a generally cylindrical shape extending in the depth direction along an extension axis L1. That is, a cross section perpendicular to the extension axis L1 of the screen plate 10 is shown in FIG.

[0017] The screen plate 10 is rotatable in the direction of the arrow F1 about the extension axis L1. An ink supply nozzle (not shown) and a squeegee 15 are disposed inside the screen plate 10.

[0018] The impression cylinder 20 has a generally cylindrical shape extending in the depth direction along the stretching axis L2. The impression cylinder 20 is rotatable in the direction of the arrow F2 relative to the stretching axis L2. The impression cylinder 20 is disposed with respect to the screen plate 10 so that the stretching axis L2 is parallel to the stretching axis L1.

[0019] The impression cylinder 20 is disposed so as to face the screen plate 10 with the printing material W therebetween.

[0020] When printing on a substrate W using such a conventional rotary screen printing device 1, the substrate W is first pulled out from a feed roller (not shown) and transported along the transport direction Fs so as to be sandwiched between the screen plate 10 and the impression cylinder 20.

[0021] As described above, the screen plate 10 rotates in the direction of the arrow F1, and the impression cylinder 20 rotates in the direction of the arrow F2. That is, the screen plate 10 and the impression cylinder 20 rotate in opposite directions while sandwiching the printing material W therebetween.

[0022] The printing substrate W is first transported in the direction of the arrow Fs and pressed against the screen plate 10 and the impression cylinder 20. At this time, the squeegee 15 in the screen plate 10 pushes ink through the screen plate onto the printing substrate W. As a result, the pattern on the screen plate is transferred to the printing substrate W, and printing is performed.

[0023] Thereafter, the printing substrate W is transported in the direction of the arrow Fe, and after the ink has dried, is collected by a take-up roller (not shown).

[0024] Here, it is known that the action of the printing material W separating from the screen 10, so-called "plate separation," has a significant effect on printing quality. For example, if the printing material W remains in contact with the screen 10 for a long period of time, problems such as the ink transferred to the printing material W bleeding due to capillary action and the image being shifted from the specified position are likely to occur.

[0025] Therefore, in the conventional rotary screen printing device 1, ideally, the printing material W comes into contact with the screen plate only at the "contact point P" (the point where the printing material W is pressed by the squeegee 15) and is released from the screen plate immediately thereafter. This allows the printing material W to be quickly released from the screen.

[0026] However, the inventors of the present application have found that even when using a rotary screen printing device 1 having such a plate release mechanism, problems often occur in the print quality of the printing substrate W. In particular, such deterioration in print quality is likely to occur when a relatively highly viscous ink is applied thickly.

[0027] The present inventors have conducted extensive research to address these problems, and have discovered that by intentionally delaying the release of the printing substrate W from the screen 10, it is possible to achieve higher quality printing than in the past.

[0028] Thus, in one embodiment of the present invention, 1. A rotary screen printing apparatus comprising: a screen plate rotatable in a first rotation direction about a first stretching axis; an impression cylinder arranged to come into contact with the screen plate via a printing medium transported along a predetermined flow, and rotatable in a second rotation direction opposite to the first rotation direction about a second stretching axis parallel to the first stretching axis; a squeegee that pushes ink onto the substrate through the screen; A roller disposed downstream of the flow of the printing medium from the impression cylinder; having A rotary screen printing apparatus is provided, wherein the roller functions to retard the release of the substrate from the screen.

[0029] Here, the expression "an object A comes into contact with a second member C through a first member B" means that there is only a clearance between the object A and the second member C, which corresponds to the first member B or its thickness.

[0030] For example, the expression "object A contacts the screen plate through the substrate W" means that there is only a clearance corresponding to the substrate W, or its thickness, between object A and the screen plate.

[0031] In one embodiment of the present invention, a printing material W is placed between the screen plate and the impression cylinder. Therefore, a clearance corresponding to the thickness of the printing material W exists between the screen plate and the impression cylinder, and strictly speaking, there is no mathematical "point of contact" between the two.

[0032] However, in this application, to avoid complicating the explanation, the aforementioned contact point P, i.e., the point where the printing material W is pressed by the squeegee, is also referred to as the "contact point P" between the screen plate and the impression cylinder.

[0033] It should be noted that this "contact point P" more generally means a "tangent line" that also extends in the depth direction.

[0034] Furthermore, "upstream" / "downstream" of the printing substrate W refers to the relative position (or temporal position) of the printing substrate W to an object along the flow as the printing substrate W is transported, with "upstream" meaning behind (or "earlier" in terms of time) such an object, and "downstream" meaning ahead (or "later" in terms of time) of such an object.

[0035] In one embodiment of the present invention, the rollers function to keep the substrate W in contact with the screen from the "contact point P" between the screen and the impression cylinder to a predetermined downstream position.

[0036] In this way, by using a mechanism that intentionally delays the separation of the printed material from the screen plate, the rotary screen printing device according to one embodiment of the present invention can perform higher quality screen printing even in printing methods such as thick film printing using highly viscous inks, where high quality printing has previously been difficult to achieve.

[0037] (Rotary screen printing apparatus according to one embodiment of the present invention) Next, with reference to FIG. 2, an example of a rotary screen printing apparatus according to one embodiment of the present invention will be described in more detail.

[0038] Fig. 2 shows an example of the configuration of a rotary screen printing apparatus (hereinafter referred to as a "first apparatus") according to an embodiment of the present invention. Fig. 2 shows a schematic cross section of the main part of the first apparatus.

[0039] 2 also shows a printing substrate W that is an object to be printed by the first device. In particular, in the example shown in Fig. 2, the printing substrate W has a sheet-like form that is transported roll-to-roll. However, the printing substrate W may have other forms.

[0040] As shown in FIG. 2, the first apparatus 100 has a screen plate 110 and an impression cylinder 120 .

[0041] The screen plate 110 has a generally cylindrical shape and is supported by a similarly generally cylindrical plate cylinder (not shown). The screen plate 110 is configured to be rotatable about a stretching axis L1. (Accordingly, the stretching axis L1 may be referred to as the "rotation axis" of the screen plate 110. The same applies to the other stretching axes.) For example, in the example shown in FIG. 2, the screen plate 110 is rotatable in the direction of the arrow F1 (counterclockwise).

[0042] An ink supply nozzle (not shown) and a squeegee 115 are disposed inside the screen plate 110 .

[0043] The impression cylinder 120 has a substantially cylindrical shape and is rotatable in the direction of the arrow F2 (clockwise) about the stretching axis L2. The impression cylinder 120 is disposed with respect to the screen plate 110 so that the stretching axis L2 is parallel to the stretching axis L1.

[0044] Moreover, the impression cylinder 120 is disposed so as to come into contact with the screen plate 110 via the printing material W.

[0045] As mentioned above, the point where the printing material W is pressed by the squeegee 115 corresponds to the “contact point P” between the screen plate 110 and the impression cylinder 120. Therefore, it is also said that the impression cylinder 120 comes into contact with the screen plate 110 at the contact point P.

[0046] The first apparatus further includes a first roller 150 .

[0047] The first roller 150 is generally cylindrical and has a third stretching axis L3. The third stretching axis L3 is parallel to the stretching axis L1 of the screen plate 110 and the stretching axis L2 of the impression cylinder 120.

[0048] The first roller 150 is configured to be rotatable around the stretching axis L3. For example, in the example shown in Fig. 2, the first roller 150 is rotatable in the direction of the arrow F3 (clockwise). The direction of the arrow F3 is the same as the direction of the arrow F2.

[0049] Here, the first roller 150 functions as described above to keep the printing material W in contact with the screen plate 110 from the contact point P between the screen plate 110 and the impression cylinder 120 to a predetermined position further downstream.

[0050] Specifically, the first roller 150 is disposed downstream of the flow of the printing material W relative to the impression cylinder 120, and comes into contact with the screen plate 110 via the printing material W at a "contact point Q."

[0051] Here, "contact Q" is used in the same manner as "contact P" described above.

[0052] That is, in the present application, a clearance corresponding to the thickness of the printing substrate W exists between the screen plate 110 and the first roller 150, and strictly speaking, there is no mathematical "contact point" between the two. However, in the present application, the point where the screen plate 110 contacts the first roller 150 via the printing substrate W is expressed as the "contact point Q" between the screen plate 110 and the first roller 150.

[0053] When printing is performed on a print medium W using the first apparatus 100 having such a configuration, first, the print medium W is transported in the direction of the arrow Fs and sandwiched between the screen plate 110 and the impression cylinder 120.

[0054] At this time, the printing material W is slightly pressed against the impression cylinder 120 by the screen plate 110 .

[0055] Moreover, the screen plate 110 rotates in the direction of the arrow F1, and the impression cylinder 120 rotates in the direction of the arrow F2. That is, the screen plate 110 and the impression cylinder 120 rotate in opposite directions while sandwiching the printing material W. The printing material W is transported in the direction of the arrow Fs while being pressed against the impression cylinder 120.

[0056] At this time, the squeegee 115 in the screen plate 110 pushes the ink through the screen plate 110 onto the printing material W. As a result, the pattern of the screen plate 110 is transferred to the printing material W, and printing is performed.

[0057] Thereafter, the printing material W is transported to the contact point Q while being adhered to the screen plate 110. In other words, the printing material W continues to be in contact with the screen plate 110 from the contact point P to the contact point Q, and does not separate from the screen during that time.

[0058] This is possible because the first roller 150 presses the printing material W against the screen plate 110 at the contact point Q.

[0059] In particular, in order to ensure that this function is performed reliably, the installation position of the first roller 150 may be determined so that the movement distance from the contact point P to the contact point Q of the printing substrate W falls within a predetermined range.

[0060] For example, when viewed from a direction perpendicular to the stretching axis L1 of the screen plate 110, the angle θ (where θ is from 0 to 180°) formed by a line segment connecting the center of the screen plate 110 to the center of the impression cylinder 120 and a line segment connecting the center of the screen plate 110 to the center of the first roller 150 may be in the range of 5°≦θ≦70°. For example, the angle θ may satisfy 15°≦θ≦60°.

[0061] By arranging the first roller 150 so as to obtain such an angle θ, the printing material W can be more reliably brought into close contact with the screen plate 110 from the point of contact P to the point of contact Q.

[0062] 2 again, the printing material W is detached from the screen plate 110 immediately after passing the contact point Q. The printing material W is then transported in the direction of the arrow Fe, and after the ink has dried, is collected by a take-up roller (not shown).

[0063] In the first device 100, by intentionally delaying the release of the printing substrate W from the plate in this manner, it is possible to achieve high-quality printing even when using highly viscous ink or performing thick-film printing.

[0064] (Rotary screen printing apparatus according to another embodiment of the present invention) Next, with reference to FIG. 3, a rotary screen printing apparatus according to another embodiment of the present invention will be described.

[0065] Fig. 3 shows an example of the configuration of a rotary screen printing apparatus according to another embodiment of the present invention (hereinafter, referred to as the "second apparatus"), in which a schematic cross section of the main part of the second apparatus is shown.

[0066] As shown in Fig. 3, the second apparatus 200 has a similar configuration to the first apparatus 100 shown in Fig. 2. Therefore, in the second apparatus 200, for components similar to those included in the first apparatus 100, reference numerals that are 100 larger than the reference numerals of the components included in the first apparatus 100 are used.

[0067] For example, the second apparatus 200 includes a screen plate 210, an impression cylinder 220, and a first roller 250, etc.

[0068] However, the second apparatus 200 differs from the first apparatus 100 in that the second apparatus 200 further includes a second roller 260 .

[0069] The second roller 260 is disposed inside the screen plate 210. The second roller 160 is disposed so as to come into contact with the first roller 150 via the screen plate 210 and the printing material W.

[0070] In the above-described first device 100, in order to perform high-quality printing, it is necessary to bring the first roller 250 into contact with the printing substrate W and further the screen plate 210 with an appropriate pressing force. However, if the pressure with which the first roller 250 is pressed against the printing substrate W becomes too high, there is a possibility that the screen plate 210 will be deformed or the printing substrate W will be scratched.

[0071] In contrast, when the second roller 260 is provided to face the first roller 250 as in the second device 200, the pressure from the side of the first roller 250 is balanced and offset by the second roller 260. Therefore, deformation of the screen plate 210 and / or damage to the printing material W is significantly suppressed.

[0072] It will be apparent to those skilled in the art that the second apparatus 200 having such a configuration can also provide the same effects as those of the first apparatus 100 described above.

[0073] In other words, in the second device 200 as well, the separation of the printing substrate W from contact point P to contact point Q can be delayed, making it possible to achieve high-quality printing even when using highly viscous ink or performing thick-film printing.

[0074] (Rotary screen printing apparatus according to yet another embodiment of the present invention) Next, with reference to FIG. 4, a rotary screen printing apparatus according to yet another embodiment of the present invention will be described.

[0075] Fig. 4 shows an example of the configuration of a rotary screen printing apparatus according to yet another embodiment of the present invention (hereinafter referred to as the "third apparatus"), in which a schematic cross section of the main parts of the third apparatus is shown.

[0076] As shown in Fig. 4, the third apparatus 300 has a similar configuration to the first apparatus 100 shown in Fig. 2. Therefore, in the third apparatus 300, for components similar to those included in the first apparatus 100, reference numerals that are 200 larger than the reference numerals of the components included in the first apparatus 100 are used.

[0077] For example, the third apparatus 300 includes a screen plate 310, an impression cylinder 320, and a first roller 350, etc.

[0078] However, in the third apparatus 300, the arrangement of the first rollers 350 is different from that in the first apparatus 100.

[0079] That is, in the third device 300, the first roller 350 is disposed away from the screen plate 310. In other words, the first roller 350 is disposed at a position where it does not come into contact with the screen plate 310 even through the printing material W.

[0080] In the case of the third apparatus 300, the substrate W ideally contacts the screen plate 310 at a contact point P and is released from the screen plate 310 at a position X.

[0081] Here, position X is located at a predetermined position on the screen plate 310 between the position where the screen plate 310 and the impression cylinder 320 contact each other (i.e., contact point P) and the position where the printing substrate W and the first roller 350 contact each other.

[0082] For example, when the angle between a line segment connecting the center of the screen plate 310 and the center of the impression cylinder 320 and a line segment connecting the center of the screen plate 310 and position X is φ (°), the position X may be in the range of 5°≦φ≦70°. In particular, the range of 15°≦φ≦30° is preferable.

[0083] In the third apparatus 300, the plate separation of the printing substrate W can be delayed, and the same effect as in the first apparatus 100 and the second apparatus 200 can be obtained. That is, in the third apparatus 300, it is possible to perform high-quality printing even when using highly viscous ink or performing thick-film printing.

[0084] The features of the rotary screen printing apparatus according to one embodiment of the present invention have been described above with reference to the first apparatus 100 to the third apparatus 300. However, it will be apparent to those skilled in the art that the rotary screen printing apparatus according to one embodiment of the present invention is not limited to these aspects and can be modified in various ways.

[0085] For example, in the first device 100 to the third device 300, the printing material W is supplied from the bottom to the top of each drawing, and after passing through the first roller, is transported toward the right of the drawing. However, the direction of transport of the printing material W is not particularly limited, and the printing material W may be supplied, for example, from left to right along the horizontal direction, and after passing through the first roller, be transported downward or upward. Alternatively, the printing material W may be transported in another direction.

[0086] In addition to the above, various modifications may be envisaged.

[0087] (Embodiments of the present invention) The present invention has the following aspects.

[0088] (Aspect 1) 1. A rotary screen printing apparatus comprising: a screen plate rotatable in a first rotation direction about a first stretching axis; an impression cylinder arranged to come into contact with the screen plate via a printing medium transported along a predetermined flow, and rotatable in a second rotation direction opposite to the first rotation direction about a second stretching axis parallel to the first stretching axis; a squeegee that pushes ink onto the substrate through the screen; A roller disposed downstream of the flow of the printing medium from the impression cylinder; having A rotary screen printing apparatus, wherein the roller functions to retard the separation of the substrate from the screen.

[0089] (Aspect 2) 2. The rotary screen printing apparatus of claim 1, wherein the roller keeps the substrate in contact with the screen plate from the contact point between the screen plate and the impression cylinder to a predetermined position downstream.

[0090] (Aspect 3) 3. The rotary screen printing apparatus according to claim 1 or 2, wherein the roller is positioned so as to contact the screen plate via the substrate.

[0091] (Aspect 4) A rotary screen printing apparatus according to any one of aspects 1 to 3, wherein the substrate continues to be in contact with the screen from the contact point to the contact position with the roller.

[0092] (Aspect 5) When viewed from a direction perpendicular to the first stretching axis of the screen plate, A rotary screen printing device according to any one of aspects 1 to 4, wherein an angle θ (where θ is from 0 to 180°) between a line segment connecting the center of the screen plate to the center of the impression cylinder and a line segment connecting the center of the screen plate to the center of the roller is in the range of 5°≦θ≦70°.

[0093] (Aspect 6) A rotary screen printing apparatus according to any one of aspects 1 to 5, further comprising a second roller arranged to contact the roller via the screen plate and the substrate.

[0094] (Aspect 7) 3. The rotary screen printing apparatus according to claim 1, wherein the roller is positioned in a position not in contact with the screen even through the substrate.

[0095] (Aspect 8) 8. The rotary screen printing apparatus of claim 7, wherein the substrate separates from the screen at a predetermined position downstream of the contact point and upstream of the roller.

[0096] (Aspect 9) When viewed from a direction perpendicular to the first stretching axis of the screen plate, A rotary screen printing device according to aspect 7 or 8, wherein the angle φ (where φ is from 0 to 180°) between the line segment connecting the center of the screen plate to the center of the impression cylinder and the line segment connecting the center of the screen plate to the specified position is in the range of 5°≦θ≦70°. [Explanation of symbols]

[0097] 1. Conventional rotary screen printing equipment 10 Screen Version 15 Squeegee 20 Impression cylinder 100 Rotary screen printing device (first device) 110 Screen Edition 115 Squeegee 120 impression cylinder 150 First Roller 200 Rotary screen printing device (second device) 210 Screen Edition 215 Squeegee 220 impression cylinder 250 First Roller 260 Second Roller 300 Rotary screen printing device (third device) 310 Screen Edition 315 Squeegee 320 impression cylinder 350 First Roller P contact Q Contact L1 Screen extension axis L2: Stretching shaft of impression cylinder L3 Roller extension shaft W Printing material

Claims

1. 1. A rotary screen printing apparatus comprising: a screen plate rotatable in a first rotation direction about a first stretching axis; an impression cylinder arranged to come into contact with the screen plate via a printing medium transported along a predetermined flow, and rotatable in a second rotation direction opposite to the first rotation direction about a second stretching axis parallel to the first stretching axis; a squeegee that pushes ink onto the substrate through the screen; A roller disposed downstream of the flow of the printing medium from the impression cylinder; having A rotary screen printing apparatus, wherein the roller functions to retard the separation of the substrate from the screen.

2. The rotary screen printing apparatus according to claim 1 , wherein the rollers keep the substrate in contact with the screen plate from the contact point between the screen plate and the impression cylinder to a predetermined position downstream.

3. The rotary screen printing apparatus according to claim 2 , wherein the roller is arranged to contact the screen plate via the substrate.

4. The rotary screen printing apparatus of claim 3 , wherein the substrate continues to contact the screen from the point of contact to the position of contact with the roller.

5. When viewed from a direction perpendicular to the first stretching axis of the screen plate, 3. A rotary screen printing device according to claim 1, wherein an angle θ (where θ is from 0 to 180°) between a line segment connecting the center of the screen plate to the center of the impression cylinder and a line segment connecting the center of the screen plate to the center of the roller is in the range of 5°≦θ≦70°.

6. 4. The rotary screen printing apparatus according to claim 3, further comprising a second roller arranged to contact the roller through the screen plate and the substrate.

7. The rotary screen printing apparatus according to claim 2 , wherein the roller is disposed at a position not in contact with the screen plate even through the printing material.

8. 8. The rotary screen printing apparatus of claim 7, wherein the substrate separates from the screen at a predetermined location downstream of the contact point and upstream of the roller.

9. When viewed from a direction perpendicular to the first stretching axis of the screen plate, 9. A rotary screen printing device according to claim 8, wherein an angle φ (where φ is from 0 to 180°) between a line segment connecting the center of the screen plate to the center of the impression cylinder and a line segment connecting the center of the screen plate to the specified position is in the range of 5°≦θ≦70°.

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