JP2014128925A - Gravure offset printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gravure offset printing method capable, even in a case where a convoluted printing pattern is targeted, of inhibiting expansion of a blanket and of forming a fine wire pattern in a favorable precision.SOLUTION: In this gravure offset printing method, a recessed portion 21 atop a gravure plate 11 corresponding to a fine wire pattern is configured obliquely to the printing direction, and the contact position of the gravure plate 11 and a blanket 6 is mobilized along the printing direction in a state where the oblique angle θ of the recessed portion 21 is being preserved. This method is capable, even in a case where the recessed portion 21 embodies a convoluted shape including a first fine line portion 22 extending along the printing direction and a second fine line portion 23 extending along a direction orthogonal to the printing direction, of inhibiting the buildup, on a printing occasion, of a printing paste P transferred onto the blanket 6 by mobilizing the contact position of the gravure plate 11 and blanket 6 along the printing direction. Even in a case where printing operations are repeatedly executed, therefore, the expansion of the blanket 6 due to the seepage therethrough of a solvent can be inhibited.

Description

  The present invention relates to a gravure offset printing method.

  For the formation of wiring patterns such as conductive circuits and electrodes used for various electronic parts such as touch panels, flexographic printing, screen printing, inkjet printing, gravure printing, gravure printing are performed according to the line width, thickness, production speed, etc. Various printing methods such as offset printing are used. Among these various printing methods, gravure offset printing has attracted attention for the formation of fine wiring patterns of, for example, several tens of μm.

  In the gravure offset printing, a gravure plate in which a concave portion corresponding to a desired printing pattern is formed and a blanket whose surface is made of silicone rubber are used (see, for example, Patent Document 1). The gravure offset printing process is broadly divided into a doctoring process for filling a gravure plate with a printing paste, an off process for transferring the printing paste filled in the depression to the surface of the blanket, and a printing paste transferred to the blanket. And a setting step for transferring the substrate to a substrate or the like. According to this printing method, the shape of the printed pattern can be freely set according to the shape of the recess, and the transfer rate of the printing paste from the blanket to the substrate is high, so that a fine wiring pattern can be accurately formed. ing.

JP 2011-240570 A JP 2005-138324 A

  By the way, in the gravure offset printing mentioned above, in order to suppress drying of printing paste, it is necessary to contain a high boiling point solvent in printing paste. Further, in order to transfer the printing paste from the blanket to the substrate with high accuracy, it is necessary that the solvent in the printing paste is sufficiently absorbed by the surface of the blanket. However, if printing is repeatedly performed and absorption of the solvent occurs at the same position on the surface of the blanket, it is considered that the blanket expands due to penetration of the solvent. When the blanket expands, the accuracy of transfer of the printing paste from the blanket to the substrate may be reduced.

  Therefore, for example, in the offset printing method described in Patent Document 2, the blanket is moved in the axial direction after the off process and the setting process are executed a predetermined number of times. In this conventional method, it is possible to prevent the solvent from being repeatedly absorbed at the same position on the blanket. However, this method is effective when the printing pattern forms a simple straight line along the printing direction. There is a demand for a method that can effectively suppress the expansion of the blanket even when the printing pattern becomes complicated as in the case of forming a pattern.

  The present invention has been made to solve the above problems, and provides a gravure offset printing method capable of suppressing the expansion of a blanket and forming a fine wiring pattern with high accuracy even when the printing pattern is complicated. For the purpose.

  In order to solve the above problems, a gravure offset printing method according to the present invention is a gravure offset printing method for printing a fine wiring pattern on a substrate, in a direction orthogonal to the first thin line portion extending in the printing direction and the printing direction. The concave portion on the gravure plate including the second thin line portion extending is arranged with an acute inclination angle with respect to the printing direction, and the inclination angle is maintained when the printing paste filled in the concave portion is transferred to the blanket. The contact position between the gravure plate and the blanket is moved in the printing direction.

  In this gravure offset printing method, the concave portion on the gravure plate corresponding to the fine wiring pattern is arranged to be inclined in the printing direction, and the contact position between the gravure plate and the blanket is moved in the printing direction while maintaining the inclination angle of the concave portion. . In this method, even when the concave portion has a complicated shape including a first thin line portion extending in the printing direction and a second thin line portion extending in a direction orthogonal to the printing direction, the contact between the gravure plate and the blanket is achieved. By moving the position in the printing direction, it is possible to prevent the printing paste transferred to the blanket from overlapping during printing. Therefore, even when printing is repeatedly executed, the expansion of the blanket due to the penetration of the solvent can be suppressed, and the fine wiring pattern can be formed with high accuracy.

  Further, it is more preferable that the electrode region portion connected to the first thin wire portion and the second thin wire portion is further included in the recess, and the contact position is moved in the printing direction so that the electrode region portions do not overlap each other. The electrode region portion tends to have a larger area than the first thin wire portion and the second thin wire portion, and the amount of the blanket that absorbs the solvent is larger than the other portions. Therefore, the expansion of the blanket due to the permeation of the solvent can be more effectively suppressed by moving the contact position in the printing direction so that the electrode region portions do not overlap each other.

  Moreover, it is preferable that the width | variety of the recessed part corresponding to a 1st fine wire part and a 2nd fine wire part is 10 micrometers-100 micrometers. This gravure offset printing method is particularly significant in that a fine wiring pattern having a width in the above range can be printed with high accuracy.

  Moreover, it is preferable that the movement amount of a contact position is 200 micrometers or more. Thereby, it can suppress more reliably that the printing paste which moves to a blanket overlaps for every printing.

  According to the gravure offset printing method according to the present invention, the expansion of the blanket can be suppressed even when the printing pattern is complicated, and the fine wiring pattern can be formed with high accuracy.

1 is a perspective view showing a main configuration of a printing apparatus to which an embodiment of a gravure offset printing method according to the present invention is applied. It is a top view which shows an example of the fine wiring pattern formed using the printing apparatus shown in FIG. It is a top view which shows an example of the recessed part arrange | positioned at the gravure plate shown in FIG. It is a perspective view which shows the doctoring process implemented using the printing apparatus shown in FIG. FIG. 5 is a perspective view showing an off process performed subsequent to the process of FIG. 4. FIG. 6 is a perspective view showing a setting process performed subsequent to the process of FIG. 5. It is a figure which shows the contact position of the gravure plate and blanket for every printing. It is a figure which shows the state of the printing paste on the blanket for every printing. It is a figure which shows the effect confirmation test result of this invention.

  Hereinafter, a preferred embodiment of a gravure offset printing method according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing a main configuration of a printing apparatus to which an embodiment of a gravure offset printing method according to the present invention is applied. As shown in FIG. 1, a printing apparatus 1 includes a first stage 2 on which a gravure plate 11 is placed, a second stage 3 on which a substrate 12 that is a printing object is placed, and a first stage 2. The second stage 3 is linearly reciprocated in a predetermined direction, the doctor blade 5 is provided so as to be press-contacted to the gravure plate 11, and is provided so as to be press-contactable to the gravure plate 11 and the substrate 12. And blanket 6.

  The printing apparatus 1 is configured as an apparatus that forms a fine wiring pattern by gravure offset printing on a substrate 12 such as a transparent conductive film used for a touch panel. As the fine wiring pattern formed on the substrate 12, for example, a so-called bezel pattern 13 having an electrode part and a wiring part and formed along the edge of the display area of the touch panel can be cited.

  The bezel pattern 13 is an aggregate of thin lines connected to the transparent electrode. For example, as shown in FIG. 2, a first thin line pattern 14 extending in a predetermined direction and a direction substantially orthogonal to the first thin line pattern 14. A pair of substantially L-shaped wiring patterns 16, 16 including a second fine line pattern 15 extending from one end of the first fine line pattern 14. An electrode pattern 17 is formed by a plurality of fine lines extending on the opposite side of the first fine line pattern 14 at the tip of the second fine line pattern 15, and a pair of substantially L-shaped wiring patterns 16, 16 The electrode patterns 17 and 17 are arranged so as to oppose each other at a predetermined interval, and the first thin line patterns 14 and 14 are arranged substantially parallel to each other. The line widths of the first fine line pattern 14 and the second fine line pattern 15 are, for example, 10 μm to 100 μm. The electrode pattern 17 is formed in a substantially rectangular region having a width of about 200 μm and a length of about 2000 μm, for example.

  The printing paste P (see FIG. 4) used for forming the fine wiring pattern can be obtained, for example, by stirring a mixture of conductive powder, resin, solvent, etc. with a three roll or the like. For the conductive powder, for example, various metals such as Ag, Au, Pt, Cu, and Al are used. The metal may be a simple substance or an alloy. Moreover, you may use what coat | covered the different metal to the particle | grains of electroconductive powder. The shape of the particles may be various shapes such as a spherical shape, a dendrite shape, and a flake shape.

  As the resin, various resins such as a thermosetting resin, an ultraviolet curable resin, and a thermoplastic resin are used. Examples of the thermosetting resin include melamine resin, epoxy resin, phenol resin, polyimide resin, and acrylic resin. Examples of the ultraviolet curable resin include acrylic resins having a (meth) acryloyl group, epoxy resins, polyester resins, and mixtures of these with monomers. Examples of the thermoplastic resin include polyester resin, polyvinyl butyral resin, cellulose resin, and acrylic resin. These resins may be used alone or in combination of two or more.

  In order to prevent the printing paste P from being dried in the printing process, the solvent preferably contains, for example, a high boiling point solvent having a boiling point of 240 ° C. or higher. Examples of such high-boiling solvents include diamylbenzene, triamylbenzene, diethylene glycol, diethylene glycol monobutyl ether acetate, diethylene glycol dibutyl ether, diethylene glycol monoacetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene. Examples include glycol monobutyl ether, tetraethylene glycol, and tetraethylene glycol monobutyl ether.

  The gravure plate 11 is formed into a plate shape by using, for example, soda lime glass or non-alkali glass. In the gravure plate 11, a drawing recess 21 corresponding to the bezel pattern 13 is formed as shown in FIG. 3. The recesses 21 are formed by etching or the like, and are arranged on the gravure plate 11 in a matrix, for example. Each recess 21 includes a pair of substantially L-shaped thin wire portions 24 each including a first thin wire portion 22 corresponding to the first thin wire pattern 14 and a second thin wire portion 23 corresponding to the second thin wire pattern 15. , 24. An electrode region portion 25 corresponding to the electrode pattern 17 is formed at the tip of the second thin wire portion 23, and the pair of substantially L-shaped thin wire portions 24, 24 are connected to each other by the electrode region portions 25, 25. The first thin line portions 22 and 22 are arranged so as to face each other at a predetermined interval and to be substantially parallel to each other.

  The line widths of the first fine line portion 22 and the second fine line portion 23 substantially match the line widths of the first fine line pattern 14 and the second fine line pattern 15 and are, for example, 10 μm to 100 μm. In addition, the formation region of the electrode region portion 25 substantially coincides with the formation region of the electrode pattern 17 and is formed in a substantially rectangular region having a width of about 200 μm and a length of about 2000 μm, for example. In the recess 21 as described above, the first thin wire portion 22 extends in the transport direction of the transport portion 4 (hereinafter referred to as “MD (Machine Direction) direction”), and the second thin wire portion 23 transports the transport portion 4. It is formed so as to extend in a direction orthogonal to the direction (hereinafter referred to as “TD (Transverse Direction) direction”), and is further inclined with an acute inclination angle θ with respect to the MD direction.

  As shown in FIG. 1, the doctor blade 5 has the first stage 2 so that the blade portion at the tip is pressed against the surface of the gravure plate 11 when the first stage 2 passes the arrangement position of the doctor blade 5. It is arrange | positioned above the conveyance path. Thereby, the printing paste P applied to the entire surface of the gravure plate 11 is scraped off, and the printing paste P is filled into the concave portion 21 of the gravure plate 11.

  The blanket 6 is configured by, for example, winding rubber or the like around the surface of a cylindrical cylinder, and is rotatable around an axis. The blanket 6 is arranged above the transport unit 4 and can be brought into pressure contact with the gravure plate 11 on the first stage 2 or the substrate 12 on the second stage 3 by driving means such as a linear servo motor. It is driven between the position and a retracted position separated from the gravure plate 11 and the substrate 12.

  The rubber on the surface 6a of the blanket 6 is preferably selected in consideration of the releasability and transferability of the printing paste P. For example, silicone rubber is used. Thereby, the hardness of the surface 6a of the blanket 6 becomes suitable, and the surface 6a of the blanket 6 when the printing paste P is transferred from the gravure plate 11 to the blanket 6 and when the printing paste P is transferred from the blanket 6 to the substrate 12 is obtained. Deformation can be optimized.

  Then, the printing process of the gravure offset printing using the printing apparatus 1 mentioned above is demonstrated.

  In this printing apparatus 1, a printing process for printing a fine wiring pattern on the substrate 12 is roughly divided into a doctoring process for filling the concave portion 21 of the gravure plate 11 with the printing paste P, and a filling for the concave portion 21. An off process of transferring the printed paste P to the surface 6 a of the blanket 6 and a setting process of transferring the print paste P transferred to the blanket 6 to the substrate 12 are executed. At the start of the printing process, the gravure plate 11 is placed on the first stage 2 and the substrate 12 is placed on the second stage 3 while performing alignment using a camera or the like. Further, the printing paste P is applied in advance to the entire surface of the gravure plate 11.

  In the doctoring process, as shown in FIG. 4, the first stage 2 on which the gravure plate 11 is placed is transported to the blanket 6 side at a predetermined speed and passes under the doctor blade 5. As a result, the doctor blade 5 is pressed against the surface of the gravure plate 11 and the printing paste P on the surface of the gravure plate 11 is scraped off by the blade portion. When the first stage 2 finishes passing the doctor blade 5, the printing paste P is filled in the concave portion 21 of the gravure plate 11.

  In the off process, the blanket 6 advances to the pressure contact position, and the first stage 2 passes below the blanket 6 as shown in FIG. Thereby, the printing paste P in the recess 21 in the gravure plate 11 is transferred to the surface 6 a of the blanket 6, and the bezel pattern 13 is drawn on the surface 6 a of the blanket 6 by the printing paste P released from the recess 21. In this off process, it is preferable that the solvent in the printing paste P is sufficiently absorbed by the surface 6 a of the blanket 6 when the printing paste P is transferred to the surface 6 a of the blanket 6. Thereby, in the subsequent setting process, the transfer accuracy of the printing paste P from the blanket 6 to the substrate 12 can be ensured.

  In the setting process, the blanket 6 moves to the retracted position, the first stage 2 returns to the initial position, and the second stage 3 is conveyed to the doctor blade 5 side than the blanket 6. Next, the blanket 6 again advances to the pressure contact position, and the second stage 3 passes below the blanket 6 as shown in FIG. Thereby, the bezel pattern 13 on the surface 6a of the blanket 6 is transferred to the substrate 12, and the printing process is completed.

  When the printing process is continuously performed, the placement of the substrate 12 on the second stage 3, the application of the printing paste P to the surface 6a of the gravure plate 11, the doctoring process, the off process, and the setting process are sequentially performed. Run. At this time, in the repeated printing process, the position of the gravure plate 11 is not changed, and the inclination angle θ (see FIG. 3) of the recess 21 with respect to the printing direction (MD direction) is maintained.

  On the other hand, as shown in FIG. 7, the initial rotation angle of the blanket 6 in the off process is shifted in the printing direction with respect to the initial rotation angle of the blanket 6 in the previous off process. Thus, as shown in FIG. 7A, when the initial contact position between the gravure plate 11 and the blanket 6 in the previous off process is S1, as shown in FIG. 7B, in the next off process. The initial contact position between the gravure plate 11 and the blanket 6 is S2 advanced in the printing direction with respect to S1. Therefore, in each off process, the contact position between the gravure plate 11 and the blanket 6 is moved in the printing direction as a whole according to the shift amount from S1 to S2, and as shown in FIG. The position of the bezel pattern 13 drawn on 6a moves in the printing direction (MD direction).

  The amount of movement of the contact position between the gravure plate 11 and the blanket 6 in each off process is not particularly limited as long as the second thin line portions 23, 23 of the recess 21 do not overlap each other, but as in the above example, When the line width of the first thin line portion 22 and the line width of the second thin line portion 23 are about 10 μm to 100 μm, for example, it is preferable to move by 200 μm or more. Moreover, when the recessed part 21 has the electrode area | region part 25, it is preferable to move the contact position of the gravure plate 11 and the blanket 6 so that electrode area | region parts 25 and 25 may not overlap. Note that the amount of movement of the contact position may be equal for each printing, but may be different for each printing.

  As described above, in this gravure offset printing method, the concave portion 21 of the gravure plate 11 corresponding to the fine wiring pattern is formed to be inclined in the printing direction, and the gravure is printed at each printing while maintaining the inclination angle θ of the concave portion 21. The contact position between the plate 11 and the blanket 6 is moved in the printing direction. In this method, even when the concave portion 21 has a complicated shape including the first thin line portion 22 extending in the printing direction and the second thin line portion 23 extending in the direction orthogonal to the printing direction, By moving the contact position with the blanket 6 in the printing direction, it is possible to prevent the printing paste P transferred to the blanket 6 from being overlapped for each printing. Therefore, even when printing is repeatedly performed, the expansion of the blanket 6 due to the permeation of the solvent can be suppressed, and a fine wiring pattern can be formed with high accuracy.

  In the present embodiment, as the concave portion of the gravure plate 11, as shown in FIG. 3, the concave portion 21 in which the substantially L-shaped thin wire portions 24 and 24 are opposed to each other is illustrated. In the concave portion 21, a wide rectangular space exists in an inner portion surrounded by the first fine wire portion 22 and the second fine wire portion 23. Therefore, the printing paste P transferred to the blanket 6 is overlapped for each printing only by moving the contact position between the gravure plate 11 and the blanket 6 in the printing direction to the extent that the second thin line portions 23, 23 of the recess 21 do not overlap each other. It can be suppressed. In this example, when the contact position between the gravure plate 11 and the blanket 6 is moved in the printing direction, the first thin line portions 22 and 22 on one side intersect with each other. The area is sufficiently small and does not affect the above effect.

  This gravure offset printing method is particularly significant in that a fine wiring pattern can be printed with high accuracy when the line width of the first thin line portion 22 and the line width of the second thin line portion 23 are about 10 μm to 100 μm. It is. In this case, when the movement amount of the contact position between the gravure plate 11 and the blanket 6 is 200 μm or more, it is possible to more reliably suppress the printing paste transferred to the blanket 6 from overlapping every printing.

  Moreover, in this embodiment, the electrode area | region part 25 connected to the 1st fine wire part 22 and the 2nd fine wire part 23 is further formed in a recessed part, and a contact position is set so that electrode area parts 25 and 25 may not overlap. It is moved in the printing direction. The electrode region portion 25 tends to have a larger area than the first thin wire portion 22 and the second thin wire portion 23, and the amount of the blanket 6 that absorbs the solvent is larger than that of the other portions. Therefore, the expansion of the blanket 6 due to the permeation of the solvent can be more effectively suppressed by moving the contact position in the printing direction so that the electrode region portions 25 do not overlap each other.

  The effect confirmation test of the present invention will be described. In this test, when printing was repeated without changing the contact position between the gravure plate and the blanket (Comparative Example), and when printing was repeated while moving the contact position between the gravure plate and the blanket in the printing direction ( In Example), the increase rate of the line width with respect to the number of printed fine wiring patterns printed on the substrate was measured.

  FIG. 9 is a diagram showing the test results. The graph A shown in the figure shows the result of the comparative example, and the graph B shows the result of the example. In the comparative example, the line width of the fine wiring pattern increases at a constant rate as the number of printed sheets increases. Thereafter, when the number of printed sheets reaches about 100, the absorption of the blanket solvent is saturated and no increase in the line width is observed. However, the increase rate of the line width when the number of printed sheets is 100 to 200 is approximately It has reached 120% to 140%. On the other hand, in the example, the line width of the fine wiring pattern is almost flat with respect to the increase in the number of printed sheets, and the increase rate of the line width over the entire range of 1 to 200 printed sheets is about −20% to 20%. It is in the range of%. From the above results, printing while moving the contact position between the gravure plate and the blanket in the printing direction as in the present invention suppresses the expansion of the blanket due to the penetration of the solvent and contributes to the improvement of the precision of the fine wiring pattern. Was confirmed.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the initial rotational angle of the blanket 6 when starting the off process is shifted to move the contact position between the gravure plate 11 and the blanket 6, but the position of the gravure plate 11 is shifted in the printing direction. In this case, the contact position between the gravure plate 11 and the blanket 6 may be moved. Moreover, in the said embodiment, although the recessed part 21 on the gravure plate 11 is formed in the state inclined with acute inclination | tilt angle (theta) with respect to MD direction, instead of making the recessed part 21 incline with respect to the gravure plate 11, The gravure plate 11 may be placed inclined with respect to the first stage 2 so that the concave portion 21 has an acute inclination angle θ with respect to the MD direction. Furthermore, in the above-described embodiment, the contact position between the gravure plate 11 and the blanket 6 is moved for each printing. However, the contact position between the gravure plate 11 and the blanket 6 is not used for each printing but after a predetermined number of times of printing. You may make it move.

  The shape of the concave portion of the gravure plate can be applied to other shapes as long as it includes a first thin line portion extending in the printing direction and a second thin line portion extending in a direction orthogonal to the printing direction. The fine wiring pattern is not limited to that for a touch panel, and can be applied to the formation of conductive circuits, electrodes, and insulating layers of electronic components such as electronic paper and solar cells. In addition, in the above embodiment, a single-wafer method using a lithographic gravure plate and a flat substrate is illustrated, but in the present invention, a roll gravure plate may be used instead of the lithographic gravure plate, Alternatively, a long sheet substrate may be used instead of the flat substrate. From the viewpoint of productivity, it is preferable to use a continuous method using a gravure plate of a roll plate and a flat substrate or a long sheet substrate.

  6 ... Blanket, 11 ... Gravure plate, 12 ... Substrate, 13 ... Bezel pattern (fine wiring pattern), 21 ... Recess, 22 ... First fine wire portion, 23 ... Second fine wire portion, 25 ... Electrode region portion, P ... print paste, θ ... tilt angle.

Claims (4)

A gravure offset printing method for printing a fine wiring pattern on a substrate,
A concave portion on the gravure plate including a first thin line portion extending in the printing direction and a second thin line portion extending in a direction orthogonal to the printing direction is disposed with an acute inclination angle with respect to the printing direction;
A gravure offset printing method, wherein when the printing paste filled in the concave portion is transferred to a blanket, the contact position between the gravure plate and the blanket is moved in the printing direction while maintaining the inclination angle. An electrode region connected to the first thin wire portion and the second thin wire portion is further included in the recess,
The gravure offset printing method according to claim 1, wherein the contact position is moved in the printing direction so that the electrode region portions do not overlap each other.   3. The gravure offset printing method according to claim 1, wherein a width of the concave portion corresponding to the first thin line portion and the second thin line portion is 10 μm to 100 μm.   The gravure offset printing method according to any one of claims 1 to 3, wherein an amount of movement of the contact position is 200 µm or more.