JP7754192B2 - Gravure printing equipment - Google Patents

Description

The present invention relates to a gravure printing apparatus.

For example, when manufacturing a multilayer ceramic capacitor, an internal electrode pattern is printed on a ceramic green sheet. Then, a mother block is manufactured by stacking the ceramic green sheets with the printed internal electrode pattern, and the mother block is then divided to manufacture individual laminate chips. Furthermore, external electrodes are formed on the end faces of the laminate chips to manufacture a multilayer ceramic capacitor. Here, the internal electrode pattern is printed by gravure printing, by transporting the ceramic green sheet at a predetermined speed between a rotating gravure roll and a pressure roll (see Patent Document 1).

Japanese Patent Application Laid-Open No. 2003-297667

However, when using gravure printing to print patterns such as internal electrode patterns on long sheet materials such as ceramic green sheets, the condition of the sheet material varies depending on temperature, humidity, and tension, making it difficult to print the pattern shapes accurately.

The present invention aims to provide a gravure printing device that can print ink in a pattern on a long sheet material with high precision.

To solve the above problem, we provide a gravure printing device that includes a gravure roll having a cylindrical outer surface on which multiple ink retaining portions are formed in a pattern, and that rotates around its axis and brings the outer surface into contact with one side of a long sheet material being transported at a predetermined speed, thereby transferring the ink held in the ink retaining portions to the sheet material and printing the ink in a pattern on the one side of the sheet material, and a speed change unit that can change the relative speed between the transport speed of the sheet material and the peripheral speed of the gravure roll at the contact point between the sheet material and the gravure roll.

The present invention provides a gravure printing device that can print ink in a pattern on a long sheet material with high precision.

1 is a cross-sectional view of a multilayer ceramic capacitor 100 manufactured by a gravure printing apparatus 1A. FIG. 1 is a perspective view of a multilayer ceramic capacitor 100. 1A is a diagram illustrating a gravure printing apparatus 1A of a first embodiment for printing an internal electrode pattern 21 on a ceramic green sheet 2. FIG. 1 shows an example of an internal electrode pattern 21 printed on a ceramic green sheet 2. FIG. 10 is a diagram illustrating a gravure printing apparatus 1B according to a second embodiment.

(First embodiment)
A gravure printing apparatus 1A according to a first embodiment of the present invention will now be described. The gravure printing apparatus 1A is used, for example, when manufacturing a multilayer ceramic capacitor 100 as shown in FIGS.

Figure 1 is a cross-sectional view of a multilayer ceramic capacitor 100 manufactured by a gravure printing apparatus 1A according to an embodiment. Figure 2 is a perspective view of the multilayer ceramic capacitor 100. The multilayer ceramic capacitor 100 comprises a laminate 110 including a dielectric layer 111 made of a ceramic dielectric material and a plurality of internal electrodes 112 laminated via the dielectric layer 111, and a pair of external electrodes 113 arranged to be conductive with the internal electrodes 112 alternately drawn out to a pair of opposing end faces 110a of the laminate 110.

The multilayer ceramic capacitor 100 is typically manufactured by stacking ceramic green sheets 2 printed with the internal electrode pattern 21 described below to create a mother block, dividing the mother block into individual laminate chips, and then performing processes such as forming external electrodes 113 and plating the external electrodes 113.

(Gravure printing device 1A)
FIG. 3 is a diagram illustrating a gravure printing apparatus 1A of the first embodiment for printing an internal electrode pattern 21 on a ceramic green sheet 2. As shown in FIG.

(Ceramic green sheet 2)
The ceramic green sheet 2 is a long sheet member formed by forming a ceramic slurry containing ceramic powder, a binder, and a solvent onto a carrier film using a die coater, gravure coater, microgravure coater, or the like.

(Gravure printing device 1A)
The gravure printing apparatus 1A includes a supply roll 3 disposed upstream in the conveying direction of the ceramic green sheet 2, and a take-up roll 4 disposed downstream. Between the supply roll 3 and the take-up roll 4, there are disposed a tension adjusting unit 5, a tension measuring unit 6, a gravure printing machine 7, a drying oven 8, and a pitch detecting unit 9, as well as a control unit 10 that controls the entire gravure printing apparatus 1A.

(Supply roll 3)
The supply roll 3 is disposed at the upstream end of the gravure printing apparatus 1A, and has the ceramic green sheet 2 wound thereon without the internal electrode pattern 21 printed thereon.

(Winding roll 4)
The take-up roll 4 is disposed at the downstream end of the gravure printing apparatus 1A, and takes up the ceramic green sheet 2 that has been supplied from the supply roll 3 and has been printed with the internal electrode pattern 21. The take-up roll 4 is connected to a take-up roll drive unit 41 that drives the take-up roll 4 to rotate.

In this embodiment, the winding roll drive unit 41 is also a speed change unit that can change the conveying speed of the ceramic green sheet 2. However, changing the conveying speed of the ceramic green sheet 2 is not limited to the winding roll drive unit 41, and a separate conveying roller or the like may be provided in the conveying path of the ceramic green sheet 2.

(Tension adjustment unit 5)
The tension adjustment unit 5 is disposed downstream of the supply roll 3. The tension adjustment unit 5 includes guide rolls 51 and 52 that change the conveying direction of the ceramic green sheet 2, and a dancer roll 53 that is disposed between the guide rolls 51 and 52 and that, in this embodiment, adjusts the tension of the ceramic green sheet 2 by displacing in the vertical direction. The tension adjustment unit 5 further includes a dancer roll drive unit 54 that drives the dancer roll 53 in the vertical direction. The tension adjustment unit 5 may be a pendulum-type dancer roll that adjusts the tension of the ceramic green sheet 2 by displacing in the horizontal direction, or a linear-acting lateral dancer roll that displaces linearly in the horizontal direction.

(Tension measuring unit 6)
A tension measuring unit 6 for measuring the tension of the ceramic green sheet 2 is disposed downstream of the tension adjusting unit 5 .

(Gravure printing machine 7)
A gravure printing machine 7 is disposed downstream of the tension measuring unit 6. The gravure printing machine 7 includes a gravure roll 71, a paste supply unit 75, a doctor blade 76, a gravure roll driving unit 77, a first pressing roll 72A, a second pressing roll 72B, and a pressing roll driving unit 78.

(Gravure Roll 71)
The gravure roll 71 is a cylindrical or columnar member that can rotate around a horizontally extending axis. The gravure roll 71 has a plurality of recesses 73 formed on its outer circumferential surface as ink retaining portions that correspond to the shapes of the internal electrode patterns 21 to be transferred to the ceramic green sheet 2. The recesses 73 are aligned in the axial and circumferential directions on the outer circumferential surface of the gravure roll 71.

(Paste supply unit 75)
Conductive paste 74 as ink is stored in paste supply unit 75. The lower portion of gravure roll 71 is immersed in conductive paste 74. When gravure roll 71 rotates and recesses 73 on the outer circumferential surface are immersed in conductive paste 74 in paste supply unit 75, conductive paste 74 is held in recesses 73.

(Doctor Blade 76)
The doctor blade 76 is arranged to contact the outer peripheral surface of the gravure roll 71 after the conductive paste 74 is held in the recesses 73. The doctor blade 76 is pressed against the outer peripheral surface of the gravure roll 71 to scrape off excess conductive paste 74 adhering to portions of the outer peripheral surface of the gravure roll 71 other than the recesses 73.

(Gravure roll driving unit 77)
The gravure roll driving unit 77 can change the peripheral speed of the outer circumferential surface of the gravure roll 71 by changing the rotation speed of the gravure roll 71. The gravure roll driving unit 77, together with the above-mentioned take-up roll driving unit 41, is a speed changing unit that can change the relative speed between the conveying speed of the ceramic green sheet 2 and the peripheral speed of the gravure roll 71 at the contact portion between the ceramic green sheet 2 and the gravure roll 71.

(First pressing roll 72A and second pressing roll 72B)
The first pressing roll 72A and the second pressing roll 72B are disposed on the upstream side and the downstream side, respectively, of the gravure roll 71 in the conveying direction of the ceramic green sheet 2. The first pressing roll 72A and the second pressing roll 72B press the ceramic green sheet 2 from the other side to wrap it around the outer peripheral surface of the gravure roll 71.
The first pressing roll 72A and the second pressing roll 72B are cylindrical or columnar members that rotate about an axis that is approximately parallel to the axis of the gravure roll 71. The outer circumferential surfaces of the first pressing roll 72A and the second pressing roll 72B may or may not be covered with an elastic member. The elastic member is made of a rubber material such as nitrile rubber, urethane rubber, silicone rubber, styrene rubber, ethylene rubber, or a resin material, but is not limited to these and may be made of other elastic materials.

(Pressing roll driving unit 78)
The pressing roll driving unit 78 can change the peripheral speeds of the outer circumferential surfaces of the first pressing roll 72A and the second pressing roll 72B by changing the rotation speeds of the first pressing roll 72A and the second pressing roll 72B. The gravure roll driving unit 77 and the pressing roll driving unit 78 can be driven separately. That is, the first pressing roll 72A and the second pressing roll 72B can be rotated at different peripheral speeds without following the rotation of the gravure roll 71.

(Drying oven 8)
A drying oven 8 for drying the printed internal electrode pattern 21 is provided downstream of the gravure printing machine 7 .

(Pitch detection unit 9)
At the outlet side of the drying furnace 8, a pitch detection unit 9 is arranged to detect the pitch of the internal electrode patterns 21 printed on the ceramic green sheets 2.

(Control unit 10)
The dancer roll driving unit 54 , tension measuring unit 6 , gravure roll driving unit 77 , pressure roll driving unit 78 , pitch detecting unit 9 , and take-up roll driving unit 41 are connected to the control unit 10 .

The control unit 10 operates the winding roll drive unit 41 in conjunction with the operation of the gravure roll drive unit 77 to rotate the winding roll 4. This causes the ceramic green sheet 2 to begin to be unwound from the supply roll 3. Note that a drive unit may also be provided on the supply roll 3 to unwind the ceramic green sheet 2. By minimizing the generation of tension between the winding roll 4, supply roll 3, and gravure plate 71 as much as possible, distortion of the printed pattern can be prevented.

The tension measuring unit 6 measures the tension of the unwound ceramic green sheet 2. The measured tension value is sent to the control unit 10.

After the tension of the ceramic green sheet 2 is measured by the tension measuring unit 6, it is transported to the gravure printing machine 7. The control unit 10 drives the gravure roll 71, first pressure roll 72A, and second pressure roll 72B via the gravure roll drive unit 77 and pressure roll drive unit 78 of the gravure printing machine 7. In the gravure printing machine 7, the ceramic green sheet 2 is pressed against the gravure roll 71 by the first pressure roll 72A and second pressure roll 72B.

When the gravure roll 71 rotates, the conductive paste 74 stored in the paste supply section 75 is held in the recess 73 of the gravure roll 71 and transported to the contact point with the ceramic green sheet 2.

During this process, a doctor blade 76 is pressed against the surface of the gravure roll 71, and the doctor blade 76 scrapes off the conductive paste 74 that has adhered to the surface of the gravure roll 71 other than the recesses 73.

As the ceramic green sheet 2 is transported, it passes over the gravure roll 71. At this time, the ceramic green sheet 2 is pressed against the outer surface of the gravure roll 71 by the first pressure roll 72A and the second pressure roll 72B, and the conductive paste 74 filled in the recesses 73 of the gravure roll 71 is transferred to the ceramic green sheet 2, printing the internal electrode pattern 21 on the ceramic green sheet 2.

The internal electrode pattern 21 printed on the ceramic green sheet 2 is dried in a drying furnace 8.

Then, the pitch detection unit 9 detects the pitch PX in the transport direction and the pitch PY in the width direction of the internal electrode pattern 21 formed on the ceramic green sheet 2. Figure 4 shows an example of an internal electrode pattern 21 printed on a ceramic green sheet 2. The arrows in the figure indicate the transport direction of the ceramic green sheet 2. Figure 4 also shows the pitch PX in the transport direction and the pitch PY in the width direction of the internal electrode pattern 21. Note that multiple positioning marks printed in the transport direction and the width direction may be arranged near the internal electrode pattern, and the positioning marks may represent the pitches PX and PY.

The values of the pitch PX in the transport direction and the pitch PY in the width direction of the internal electrode patterns 21 detected by the pitch detection unit 9 are sent to the control unit 10. A monitor or the like may be installed in the control unit 10 so that an operator can measure the pitch PX and the pitch PY in the width direction using an image.

The ceramic green sheet 2 is then wound onto the winding roll 55.

The control unit 10 compares the tension value of the fed ceramic green sheet 2 and the pitch PX in the transport direction and pitch PY in the width direction of the internal electrode pattern 21 with target values. If the pitch PX and pitch PY differ from the target values, the control unit 10 feeds back the results and operates the dancer roll drive unit 54, gravure roll drive unit 77, pressure roll drive unit 78, and winding roll drive unit 41.

(1) For example, when the pitch PX differs from the target value, the control unit 10 can change the rotation speed of the gravure roll 71, i.e., the peripheral speed of the outer surface of the gravure roll 71, relative to the conveying speed of the ceramic green sheet 2 via the gravure roll drive unit 77.

When the control unit 10 controls the gravure roll driving unit 77 to slow the peripheral speed of the gravure roll 71 relative to the transport speed of the ceramic green sheet 2, the pitch PX of the internal electrode patterns 21 in the transport direction becomes longer.
Conversely, when the control unit 10 controls the gravure roll driving unit 77 to increase the peripheral speed of the gravure roll 71 relative to the conveying speed of the ceramic green sheet 2, the pitch PX of the internal electrode patterns 21 in the conveying direction becomes shorter.

In this way, by changing the peripheral speed of the gravure roll 71 relative to the conveying speed of the ceramic green sheet 2, the pitch PX of the internal electrode pattern 21 in the conveying direction can be adjusted.

(2) Furthermore, the control unit 10 can change the conveying speed of the ceramic green sheet 2 by operating the winding roll drive unit 41 to change the rotational speed of the winding roll 4 in accordance with the operation of the gravure roll drive unit 77 while keeping the peripheral speed of the gravure roll 71 constant.
For example, if the conveying speed of the ceramic green sheet 2 is made faster than the circumferential speed of the gravure roll 71, the pitch PX in the conveying direction of the internal electrode patterns 21 becomes longer. Conversely, if the conveying speed of the ceramic green sheet 2 is made slower than the circumferential speed of the gravure roll 71, the pitch PX in the conveying direction of the internal electrode patterns 21 becomes shorter.

In this way, by changing the conveying speed of the ceramic green sheet 2 relative to the peripheral speed of the gravure roll 71, the pitch PX of the internal electrode pattern 21 in the conveying direction can be adjusted.

The gravure roll 71, the first pressure roll 72A, and the second pressure roll 72B can be driven individually. The first pressure roll 72A, the second pressure roll 72B, the take-up roll 4, and the supply roll 3 basically rotate at the same speed to prevent distortion of the image due to tension.

(3) Furthermore, the control unit 10 can change the tension of the ceramic green sheet 2 by moving the dancer roll 53 up and down via the dancer roll drive unit 54 of the tension adjustment unit 5.

For example, when the dancer roll 53 is moved downward by the dancer roll drive unit 54, the tension on the ceramic green sheet 2 increases. This causes the ceramic green sheet 2 to stretch in the transport direction and narrow in width. When ink is transferred from the recesses 73 to the ceramic green sheet 2 that has stretched in the transport direction and narrowed in width, when the tension is released, the pitch PX of the transferred ink in the transport direction shrinks and the pitch PY in the width direction becomes wider compared to when printing was performed under low tension.

Conversely, when the dancer roll 53 is moved upward by the dancer roll drive unit 54, the tension on the ceramic green sheet 2 decreases. This causes the ceramic green sheet 2 to shrink in the conveyance direction and increase in width. When ink is transferred from the recesses 73 to the ceramic green sheet 2 that has shrunk and increased in width in the conveyance direction, when the tension is released, the pitch PX of the transferred ink in the conveyance direction increases and the pitch PY in the width direction decreases compared to when printing was performed under high tension.

As described above, according to this embodiment, a speed change unit (gravure roll drive unit 77 and winding roll drive unit 41) is provided that can change the relative speed between the conveying speed of the ceramic green sheet 2, which is a sheet member, and the peripheral speed of the gravure roll 71 at the contact portion between the ceramic green sheet 2 and the gravure roll 71.

Therefore, the speed change unit (gravure roll drive unit 77 and winding roll drive unit 41) can change the relative speed between the conveying speed of the ceramic green sheet 2 and the peripheral speed of the gravure roll 71, making it possible to fine-tune the pitch of the internal electrode pattern 21 and print the internal electrode pattern 21 with high precision.

In addition, according to this embodiment, a tension adjustment unit 5 is provided that can adjust the tension of the ceramic green sheet 2, which is a sheet member.

The tension of the ceramic green sheet 2 can be changed by moving the dancer roll 53 up and down via the dancer roll drive unit 54 of the tension adjustment unit 5, so the pitch of the internal electrode pattern 21 can be finely adjusted and the internal electrode pattern 21 can be printed with high precision.

Furthermore, in the first embodiment, by changing the rotation speed of the first pressing roll 72A and the second pressing roll 72B, the tension when the ceramic green sheet 2 comes into contact with the gravure roll 71 can be adjusted, and the first pressing roll 72A and the second pressing roll 72B can also function as tension adjustment units. Note that the first pressing roll 72A and the second pressing roll 72B do not need to be connected to a drive mechanism, and may simply rotate in accordance with the transport speed of the winding roll.

This allows the tension of the ceramic green sheet 2 to be changed and the pitch of the internal electrode pattern 21 to be fine-tuned, allowing the internal electrode pattern 21 to be printed with high precision.

Second Embodiment
Next, a gravure printing apparatus 1B according to a second embodiment of the present invention will be described. Fig. 5 is a diagram illustrating a gravure printing apparatus 1B according to the second embodiment of the present invention.

The gravure printing apparatus 1B of the second embodiment has a single pressure roll 72 instead of the first pressure roll 72A and second pressure roll 72B of the first embodiment. The pressure roll 72 is arranged opposite the gravure roll 71 and sandwiches the ceramic green sheet 2 between it and the gravure roll 71. The pressure roll 72 is a cylindrical or columnar member that rotates about an axis approximately parallel to the axis of the gravure roll 71. The outer peripheral surface of the pressure roll 72 is covered with an elastic member, similar to the first pressure roll 72A and second pressure roll 72B.

The second embodiment also includes a speed change unit (gravure roll drive unit 77 and winding roll drive unit 41) that can change the relative speed between the conveying speed of the ceramic green sheet 2, which is a sheet member, and the peripheral speed of the gravure roll 71 at the contact point between the ceramic green sheet 2 and the gravure roll 71.

Therefore, the speed change unit (gravure roll drive unit 77 and take-up roll drive unit 41) can change the relative speed between the conveying speed of the ceramic green sheet 2 and the peripheral speed of the gravure roll 71. This makes it possible to finely adjust the pitch of the internal electrode pattern 21, enabling the internal electrode pattern 21 to be printed with high precision.

It also has a tension adjustment unit 5 that can adjust the tension of the ceramic green sheet 2, which is a sheet member.

The tension of the ceramic green sheet 2 can be changed by moving the dancer roll 53 up and down via the dancer roll drive unit 54 of the tension adjustment unit 5. This allows fine adjustment of the pitch of the internal electrode pattern 21, enabling the internal electrode pattern 21 to be printed with high precision.

The above describes embodiments of the present invention, but the present invention is not limited to these embodiments and various applications and modifications can be made within the scope of the invention.

1A, 1B Gravure printing device 2 Ceramic green sheet (sheet member)
3 Supply roll 4 Winding roll 5 Tension adjustment unit 6 Tension measurement unit 7 Gravure printing machine 9 Pitch detection unit 10 Control unit 21 Internal electrode pattern 41 Winding roll driving unit (speed change unit)
51 Guide roll 52 Guide roll 53 Dancer roll 54 Dancer roll drive unit 55 Winding roll 71 Gravure roll 72 Pressing roll 72A First pressing roll 72B Second pressing roll 73 Recessed portion (ink holding portion)
74 Conductive paste 77 Gravure roll driving unit (speed changing unit)
78 Pressing roll drive unit

Claims (6)

A gravure printing apparatus for printing a pattern used in a multilayer ceramic capacitor,
a gravure roll having a cylindrical outer peripheral surface on which a plurality of ink retaining portions are formed in a pattern, the gravure roll rotating about an axis and bringing the outer peripheral surface into contact with one surface of a long sheet member being transported at a predetermined speed, thereby transferring the ink retained in the ink retaining portions to the sheet member and printing the ink in a pattern on the one surface of the sheet member;
a speed change unit that can change the relative speed between a conveying speed of the sheet member and a peripheral speed of the gravure roll at a contact portion between the sheet member and the gravure roll;
a control unit that compares the pitch of the ink printed in a pattern with a target value, and if the pitch differs from the target value, feeds back the result to the speed change unit;
Gravure printing equipment. The speed change unit
The peripheral speed of the gravure roll is changeable.
The gravure printing apparatus according to claim 1 . A tension adjusting unit is provided that can adjust the tension of the sheet member.
The gravure printing apparatus according to claim 1 or 2. The tension adjusting unit includes a dancer roll.
The gravure printing apparatus according to claim 3. a gravure roll driving unit that drives the gravure roll to rotate;
a pressing roll that sandwiches the sheet member between itself and the gravure roll and presses the sheet member toward the gravure roll;
a pressing roll driving unit that can rotate the pressing roll at a peripheral speed different from that of the gravure roll;
The gravure printing apparatus according to claim 1 . a first pressing roll and a second pressing roll, which are respectively arranged on the upstream side and the downstream side of the gravure roll in the conveying direction of the sheet member, and which press the sheet member from the other side to wind it around the outer peripheral surface of the gravure roll,
The gravure printing apparatus according to claim 1 .