JP2017221865A - Gravure coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gravure coating device capable of forming a thin and uniform coating layer.SOLUTION: In an outer peripheral surface of a plate cylinder 2, a large number of first diagonal line grooves 2a slantingly extending in a rotational direction toward one end side of the rotational axis C1 and a large number of second diagonal line grooves 2b slantingly extending in the rotational direction toward the other end side of the rotational axis C1 are formed. A tip-pointed conical projection 2c is provided in a surrounded part between a first diagonal line groove 2a and a neighboring adjacent second diagonal line groove 2b. The projection parts 2c each contact at a point with a doctor blade 4 when a coating liquid 10 is scratched off by the doctor blade 4.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a gravure coating apparatus that coats a web that is continuously conveyed with a coating liquid.

  Conventionally, when a coating layer is formed on a web surface using a gravure coating apparatus, it is generally known to use a plate cylinder having an oblique groove formed on the outer peripheral surface. The slanted groove portion has a shape extending in a spiral shape inclining in the rotational direction as it goes to one end side of the rotational axis of the plate cylinder, and the web is transferred to the outer periphery of the plate cylinder in a state where the coating liquid is supplied. The web is rotated by the direction opposite to the conveying direction and the web is contacted with the web while scraping off the excess coating liquid adhering to the outer peripheral surface of the plate cylinder with a doctor blade, and the web is filled with the coating liquid filled in the oblique groove portion. And a liquid pool portion called a bead straddling between the plate cylinder and the outer peripheral surface of the plate cylinder, the coating liquid of the liquid pool portion is transferred to the web.

  Incidentally, in recent years, when forming a coating layer on the web surface, it may be required to make the coating layer as thin and uniform as possible.

  However, when coating is performed with the plate cylinder having the oblique groove portion formed on the outer peripheral surface as described above, the coating liquid accumulated in the liquid reservoir due to the movement of the oblique groove portion due to the rotation operation of the plate cylinder is applied to one end side of the rotation axis. Move gradually toward. Therefore, since the liquid surface of the coating liquid collected in the liquid reservoir becomes higher on one end side than the other end side of the rotation axis, the thickness of the coating layer formed on the web surface becomes non-uniform. There was a problem that the thickness of the coating layer was thin and it was difficult to form it uniformly.

  In order to cope with this problem, not only the oblique groove portion extending obliquely in the rotational direction as the oblique groove portion formed on the outer peripheral surface of the plate cylinder extends toward one end side of the rotational axis of the plate cylinder, but also the rotational axis of the plate cylinder. It is conceivable to form a slanted groove portion extending in the rotational direction as it goes to the other end side so that the liquid surface of the coating liquid accumulated in the liquid reservoir portion becomes uniform along the rotation axis.

  For example, the outer peripheral surface of the plate cylinder of the gravure coating apparatus disclosed in Patent Document 1 is inclined in the rotational direction as it goes to one end side of the rotation axis of the plate cylinder as shown in a schematic enlarged view in FIG. A plurality of first oblique groove portions 12a extending in the direction of the rotation axis of the plate cylinder and a plurality of second oblique groove portions 12b extending in the rotational direction toward the other end side of the plate cylinder are formed, and each first oblique groove portion 12a is formed. And the second oblique groove portions 12b are arranged in parallel at equal intervals along the rotation axis. A plurality of protrusions 12c having a wide flat surface 12d at the tip are formed in a portion surrounded by two adjacent first oblique groove portions 12a and two adjacent second oblique groove portions 12b. When the coating layer is formed on the web surface, the doctor blade scrapes off the coating liquid adhering to the flat surface of each protrusion 12c.

JP2015-44135A

  However, each first oblique line groove portion 12a and each second oblique line groove portion 12b in Patent Document 1 have a symmetrical shape in the direction along the rotation axis, and the arrangement of each protrusion portion 12c on the outer peripheral surface of the plate cylinder is as follows. A large number of annular projection groups 12A each consisting of a large number of protrusions 12c arranged in a straight line along the rotation direction are arranged regularly at equal intervals along the rotation axis. Therefore, the portion corresponding to each annular protrusion group 12A of the liquid reservoir portion is a coating liquid that is stored by the flat surface 12d of each protrusion portion 12c as compared to the portion 12B not corresponding to each annular protrusion group of the liquid reservoir portion. The amount of the coating liquid is reduced, and the liquid level of the coating liquid that accumulates in the liquid reservoir portion becomes wavy along the rotation axis, so that the streaks extend in the web conveyance direction on the surface of the coating layer formed on the web surface. If the pattern is formed and the pattern becomes clearly visible, it may be determined that the coating is poor.

  This invention is made | formed in view of such a point, The place made into the objective is providing the gravure coating apparatus which can form a thin coating thickness and uniform coating layer.

  In order to achieve the above object, the present invention is characterized in that the shape of each protrusion formed on the outer peripheral surface of the plate cylinder has been devised.

  Specifically, a plate cylinder that transfers to the web a coating liquid that adheres to the outer peripheral surface while rotating in the opposite direction with respect to the web that is continuously conveyed, and the outer peripheral surface in contact with the outer peripheral surface of the plate cylinder The following solution was taken for a gravure coating apparatus provided with a doctor blade that scrapes and removes excess coating liquid adhering to the plate cylinder by rotating the plate cylinder.

  That is, according to the first aspect of the invention, the outer periphery of the plate cylinder extends in an inclined direction in the rotation direction toward one end of the rotation axis, and is arranged in parallel at equal intervals along the rotation axis. A large number of first oblique groove portions filled with the working liquid, and extending in a rotational direction as it goes to the other end side of the rotation axis, and arranged in parallel at equal intervals along the rotation axis. A plurality of second oblique line grooves that are filled, and a plurality of protrusions formed between two adjacent first oblique line grooves and two adjacent second oblique line grooves, each of the protrusions being The tip has a sharp conical shape, and when the coating liquid is scraped off by the doctor blade, it is configured to hit the doctor blade.

  In a second invention, in the first invention, the thickness t1 of the doctor blade is such that the interval in the rotation direction of the plate cylinder in two adjacent projections of the projections is D1, and the rotation of the plate cylinder When the angle of the doctor blade with respect to the outer peripheral surface of the plate cylinder when viewed in the axial extension direction is θ, t1 ≧ D1 × sin θ is set.

  According to a third invention, in the first or second invention, the doctor blade has its tip end directed in the opposite direction to the rotation direction of the plate cylinder, and an extension of the rotation axis of the plate cylinder. The plate cylinder is in contact with the outer peripheral surface of the plate cylinder so as to have an acute posture with respect to the outer peripheral surface of the plate cylinder when viewed in the direction.

  According to a fourth invention, in any one of the first to third inventions, the protrusion on the downstream side in the rotational direction relative to the protrusion on the upstream side in the rotational direction of the two protrusions adjacent in the rotational direction of the plate cylinder. The position is set so as to be shifted by an angle of 0 ° <θ ≦ 1 ° toward one end of the rotation axis with respect to the rotation direction of the plate cylinder.

  According to a fifth invention, in any one of the first to fourth inventions, the total sum of the opening portions of the first oblique line groove portions and the second oblique line groove portions with respect to the total area of the outer peripheral surface of the plate cylinder. The area ratio is set to 90% or more.

  In the first invention, since the amount of the coating liquid adhering to each protrusion scraped off by the doctor blade is reduced, the amount of the coating liquid accumulated in the liquid reservoir portion in the direction along the rotation axis is uneven. The difference with no part becomes slight. Therefore, the liquid level of the coating liquid collected in the liquid reservoir becomes substantially uniform along the rotation axis, and the coating layer formed on the web surface can be made thin and uniform.

  In the second invention, when the doctor blade scrapes off the excess coating liquid adhering to the outer peripheral surface of the plate cylinder, the tip portion of the doctor blade does not fit into the first and second oblique groove portions. Therefore, when the distal end portion of the doctor blade is repeatedly fitted in the first and second oblique groove portions, the doctor blade vibrates, and the occurrence of abnormal noise during coating increases due to the vibration. In addition to preventing this, it is possible to reduce the number of maintenances by preventing the progress of wear of the tip of the doctor blade due to vibration from increasing.

  In the third aspect of the invention, the contact pressure of the doctor blade with respect to the outer periphery of the plate cylinder necessary for scraping off the excess coating liquid adhering to the outer periphery of the plate cylinder can be lowered. You can slow down and reduce the number of maintenance.

  In the fourth aspect of the invention, the protrusions do not line up regularly along the rotation direction as in Patent Document 1, and therefore the uneven portions of the protrusions in the direction along the rotation axis of the outer peripheral surface of the plate cylinder are not uneven. And disappear. Therefore, when the doctor blade scrapes off the excess coating liquid adhering to the outer peripheral surface of the plate cylinder, each protrusion contacting the tip portion of the doctor blade is periodically dispersed in the direction along the rotation axis, It is possible to prevent the wear generated at the tip of the doctor blade from being biased.

  In the fifth invention, since the portion of the outer periphery of the plate cylinder that contacts the doctor blade is extremely small, for example, even in the case of coating using a coating liquid having the property of shear aggregation, The amount of the coating liquid that aggregates between the protrusions can be reduced, and defects in the coating layer that occur when the aggregated coating liquid adheres to the tip of the doctor blade can be suppressed.

It is the schematic which looked at the gravure coating device concerning the embodiment of the present invention from the side. It is a top view of the gravure coating device concerning the embodiment of the present invention. FIG. 3 is an enlarged view of III in FIG. 2. It is sectional drawing in the IV-IV line of FIG. FIG. 4 is a view taken in the direction of arrow V in FIG. 3. FIG. 6 is a view taken in the direction of arrow VI in FIG. 4. It is a figure which shows the determination result of the external appearance of the coating layer formed by coating, changing each parameter using the gravure coating apparatus which concerns on embodiment of this invention. 2 is a partially enlarged view of a plate cylinder outer peripheral surface of Patent Document 1. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiment is merely exemplary in nature.

  1 and 2 show a gravure coating apparatus 1 according to an embodiment of the present invention. The gravure coating apparatus 1 performs so-called kiss-reverse coating, and is guided upward by a plurality of guide rolls 11 (only two are shown in FIG. 1) (the transport direction Z1 in FIG. 1). ), The coating liquid 10 is transferred to the surface of the web W1 continuously conveyed to form a coating layer on the surface of the web W1.

  The gravure coating apparatus 1 includes a plate cylinder 2 that can rotate around a rotation axis C1, and the plate cylinder 2 contacts the surface of the web W1 while rotating in the opposite direction with respect to the web W1. Yes.

  On the outer peripheral surface of the plate cylinder 2, as shown in FIG. 3, there are a large number of first oblique groove portions 2a extending in an inclined direction in the rotational direction X1 toward the one end side of the rotational axis C1, and other rotational axes C1. A large number of second oblique groove portions 2b extending in the rotational direction X1 as it goes to the end side are provided.

  Each said 1st oblique line groove part 2a and each said 2nd oblique line groove part 2b are arranged in parallel along the said rotating shaft center C1, respectively, and the coating liquid 10 is satisfy | filled when performing coating. Yes.

  A protrusion 2c is formed in a portion surrounded by two adjacent first oblique groove portions 2a and two adjacent second oblique groove portions 2b.

  As shown in FIGS. 4 to 6, the protrusion 2 c has a conical shape with a sharp tip, and a large number of the protrusions 2 c are provided over the entire outer peripheral surface of the plate cylinder 2.

  Of the two protrusions 2c adjacent to the rotation direction X1 of the plate cylinder 2, the protrusion 2c on the downstream side in the rotation direction with respect to the protrusion 2c on the upstream side in the rotation direction rotates with respect to the rotation direction X1 of the plate cylinder 2. The angle is set so as to be shifted by 1 ° toward one end of the axis C1.

  In addition, the inclination with respect to the rotation direction X1 between each projection part 2c of FIG. 3 is exaggerated for convenience.

  The ratio of the total total area of the opening portions of the first oblique line groove portions 2a and the second oblique line groove portions 2b to the area of the entire outer peripheral surface of the plate cylinder 2 (hereinafter, this ratio is referred to as an opening ratio). Is set to 90%.

  As shown in FIGS. 1 and 2, a coating chamber 3 extending along the rotation axis C <b> 1 of the plate cylinder 2 is provided on one side in the radial direction of the plate cylinder 2.

  The coating chamber 3 includes a chamber body 3a having a substantially U-shaped cross section that opens to the plate cylinder 2 side, and the inside of the chamber body 3a serves as a liquid reservoir 3b that stores the coating liquid 10 therein. Yes.

  A bulging portion 3c having a trapezoidal cross section that bulges toward the plate cylinder 2 is formed at the center of the inner surface forming the liquid reservoir 3b of the chamber body 3a.

  An inflow hole 3d having a substantially S-shaped cross section for allowing the coating liquid 10 to flow into the liquid reservoir 3b is formed at the lower center of the chamber body 3a in the longitudinal direction. Are formed with a pair of outflow holes 3e having a substantially S-shaped cross section through which the coating liquid 10 flows out from the liquid reservoir 3b.

  A plate-shaped resin doctor blade 4 having flexibility extending along the rotation axis C1 of the plate cylinder 2 is provided on the plate cylinder 2 side above the chamber body 3a by a fixed block 5 in a posture that extends downward. The front end of the plate cylinder 2 is fixed to the outer circumferential surface of the plate cylinder 2 so as to face in the opposite direction to the rotation direction X1 of the plate cylinder 2 and in the extending direction of the rotation axis C1 of the plate cylinder 2. The plate cylinder 2 is in contact with the outer peripheral surface so as to have an acute posture.

  As shown in FIG. 5, the doctor blade 4 has a thickness t <b> 1 such that an interval in the rotation direction X <b> 1 of the plate cylinder 2 between two adjacent projections 2 c of the projections 2 c is D <b> 1. When the angle of the doctor blade 4 with respect to the extending direction of the rotation axis C1 is θ, t1 ≧ D1 × sin θ is set.

  On the other hand, on the side of the plate cylinder 2 below the chamber body 3a and at a position facing the doctor blade 4, the flexibility extending along the rotation axis C1 of the plate cylinder 2 is shown in FIG. A resin sealing plate 6 having a straight line is fixed by a fixing block 7 in a posture that extends straight upward, and its tip contacts the outer peripheral surface of the plate cylinder 2 to the upstream side in the rotational direction of the plate cylinder 2 of the liquid reservoir 3b. Is sealed.

  As shown in FIG. 2, a pair of resin side seals 8 are attached to both ends of the coating chamber 3 in the longitudinal direction, and the doctor blade 4, the seal plate 6 and the side seals 8 The reservoir 3b is sealed.

  At the tip of the doctor blade 4, the plate cylinder 2 is circulated while circulating the coating liquid 10 accumulated in the liquid reservoir 3b through the inflow hole 3d and the outflow hole 3e by a coating liquid circulation device (not shown). When rotated, the excess coating liquid 10 adhering to the outer peripheral surface of the plate cylinder 2 is scraped off and measured.

  When the excess coating liquid 10 adhering to the outer peripheral surface of the plate cylinder 2 is scraped off by the doctor blade 4, the tip of each projection 2 c hits the doctor blade 4. The coating liquid 10 adhering to the tip of each protrusion 2c is scraped off by the doctor blade 4 and removed.

  The gravure coating apparatus 1 is filled with each of the first oblique groove portions 2a and each of the second oblique groove portions 2b when the plate cylinder 2 contacts the web W1 continuously conveyed while rotating. The coating liquid 10 in the liquid reservoir 9 is transferred to the web W1 while forming the liquid reservoir 9 straddling the web W1 and the outer peripheral surface of the plate cylinder 2 with the coating liquid 10. It has become.

  Next, the determination result of the appearance of the coating layer formed on the web W1 while changing each parameter using the gravure coating apparatus 1 according to the embodiment of the present invention will be described.

  In FIG. 7, a streak pattern appears on the surface of the coating layer formed on the web W1 while changing the number of first oblique groove portions 2a and the second oblique groove portions 2b (hereinafter referred to as the number of lines) and the aperture ratio. The result of evaluating whether or not. If the surface of the coating layer does not appear to have a streak pattern, ◎, if the surface of the coating layer shows a streak pattern but does not cause problems when used as a product, ○ When a streak pattern appeared and became a product, it was marked as x.

  From this result, it was found that in the plate cylinder 2 of the present invention, when the aperture ratio is 90%, a coating layer that does not cause a problem as a product can be formed regardless of the number of lines.

  As described above, according to the embodiment of the present invention, since the amount of the coating liquid adhering to each protrusion 2c scraped off by the doctor blade 4 is reduced, the coating accumulated in the liquid reservoir 9 in the direction along the rotation axis C1. The difference between the portion where the amount of the working liquid 10 is uneven and the portion where the amount is not uneven becomes small. Therefore, the liquid level of the coating liquid 10 collected in the liquid reservoir 9 becomes substantially uniform along the rotation axis C1, and the coating layer formed on the surface of the web W1 is made thin and uniform. it can.

  Further, the thickness t1 of the doctor blade 4 is such that the interval in the rotation direction X1 of the plate cylinder 2 between two adjacent projections 2c of the projections 2c is D1 and the extension direction of the rotation axis C1 of the plate cylinder 2 is seen. If the angle of the doctor blade 4 with respect to the outer peripheral surface of the plate cylinder 2 is θ, t1 ≧ D1 × sin θ is set so that the doctor blade 4 adheres to the outer peripheral surface of the plate cylinder 2. When the working liquid 10 is scraped off, the distal end portion of the doctor blade 4 does not fit into the first oblique groove portion 2a and the second oblique groove portion 2b. Accordingly, the doctor blade 4 is vibrated by repeatedly fitting the distal end portion of the doctor blade 4 into the first oblique groove portion 2a and the second oblique groove portion 2b, and the vibration causes significant noise during coating. It is possible to prevent such a situation from occurring, and it is possible to reduce the number of maintenances by preventing the progress of wear of the tip of the doctor blade 4 due to vibration from being accelerated.

  Further, the doctor blade 4 is arranged on the outer peripheral surface of the plate cylinder 2 so that the tip of the doctor blade 4 is directed in the direction opposite to the rotation direction X1 of the plate cylinder 2 and viewed in the extending direction of the rotation axis C1 of the plate cylinder 2. The plate cylinder 2 of the doctor blade 4 required for scraping off the excess coating liquid 10 adhering to the outer peripheral surface of the plate cylinder 2 is in contact with the outer peripheral surface of the plate cylinder 2 so as to have an acute posture. The contact pressure with respect to the outer peripheral surface of the doctor blade 4 can be lowered, the degree of wear of the tip of the doctor blade 4 can be slowed down, and the number of maintenance can be reduced.

  Of the two protrusions 2c adjacent to the rotation direction X1 of the plate cylinder 2, the protrusion 2c on the downstream side in the rotation direction X1 of the plate cylinder 2 rotates the rotation direction of the plate cylinder 2 with respect to the protrusion 2c on the upstream side. Since the position is shifted to one end side of the rotation axis C1 with respect to X1, the protrusions 2c are not arranged in a straight line along the rotation direction X1 as in Patent Document 1, and the outer peripheral surface of the plate cylinder 2 The portions where the projections 2c are uneven and the portions where they are not uneven in the direction along the rotational axis C1 are eliminated. Therefore, when the doctor blade 4 scrapes off the excess coating liquid 10 adhering to the outer peripheral surface of the plate cylinder 2, each protrusion 2c that contacts the tip portion of the doctor blade 4 is periodically in the direction along the rotation axis C1. It is possible to prevent the wear generated at the tip of the doctor blade 4 from being biased.

  In addition, since the aperture ratio on the outer peripheral surface of the plate cylinder 2 is set to 90%, the portion of the outer peripheral surface of the plate cylinder 2 that contacts the doctor blade 4 becomes very small, for example, a coating having a characteristic of shear aggregation. Even in the case of coating using the working liquid 10, the amount of the coating liquid 10 that aggregates between the tip of the doctor blade 4 and each protrusion 2 c can be reduced, and the aggregated coating liquid 10 becomes the doctor blade. The defect of the coating layer which generate | occur | produces by adhering to the front-end | tip of 4 can be suppressed.

  In the embodiment of the present invention, the aperture ratio on the outer peripheral surface of the plate cylinder 2 is set to 90%. However, if the aperture ratio is set to 90% or more in the plate cylinder 2 of the embodiment of the present invention. Similar effects can be obtained.

  Further, in the embodiment of the present invention, the position of the protrusion 2 c on the downstream side in the rotation direction with respect to the protrusion 2 c on the upstream side in the rotation direction of the two protrusions 2 c adjacent in the rotation direction X 1 of the plate cylinder 2 is the plate cylinder 2. The angle θ is set to be shifted by 1 ° toward the one end side of the rotation axis C1 with respect to the rotation direction X1, but the deviation angle θ may be 0 ° <θ ≦ 1 °.

  Further, in the embodiment of the present invention, the plate cylinder is seen so that the tip of the doctor blade 4 is directed in the opposite direction to the rotation direction X1 of the plate cylinder 2 and viewed in the extending direction of the rotation axis C1 of the plate cylinder 2. 2 is in contact with the outer peripheral surface of the plate cylinder 2 so as to have an acute posture with respect to the outer peripheral surface of the plate cylinder 2, so that the tip of the doctor blade 4 is along the rotation direction X <b> 1 of the plate cylinder 2. A configuration in which the outer peripheral surface of the plate cylinder 2 is brought into contact with the outer peripheral surface of the plate cylinder 2 when viewed in the extending direction of the rotation axis C1 may be employed.

  Further, the distal end of the doctor blade 4 in the embodiment of the present invention is in contact with a large number of the projecting portions 2c among the projecting portions 2c in a state of contacting the outer peripheral surface of the plate cylinder 2 in a stationary state. By setting the thickness t1, it is possible to reliably prevent the generation of abnormal noise due to the vibration of the doctor blade 4 at the time of coating and the uneven bias of the tip of the doctor blade 4.

  The present invention is suitable for a gravure coating apparatus that coats a web that is continuously conveyed.

DESCRIPTION OF SYMBOLS 1 Gravure coating apparatus 2 Plate cylinder 2a 1st oblique line groove part 2b 2nd oblique line groove part 2c Protrusion part 4 Doctor blade t1 Doctor blade thickness C1 Rotation center W1 Web

Claims (5)

A plate cylinder for transferring the coating liquid adhering to the outer peripheral surface to the web while rotating in the opposite direction with respect to the continuously conveyed web;
A gravure coating apparatus comprising a doctor blade that contacts an outer peripheral surface of the plate cylinder and adheres to the outer peripheral surface by scraping and removing the excess coating liquid by the rotational operation of the plate cylinder,
On the outer peripheral surface of the plate cylinder, a plurality of first plates that extend obliquely in the rotation direction toward one end side of the rotation axis and are arranged in parallel at equal intervals along the rotation axis are filled with the coating liquid. 1 oblique line groove part and many 2nd oblique line groove parts which are inclined and extended in the rotation direction as going to the other end side of the rotation axis, and are arranged in parallel at equal intervals along the rotation axis. And a plurality of protrusions formed between two adjacent first oblique groove portions and two adjacent second oblique groove portions,
Each of the protrusions has a conical shape with a sharp tip, and is configured to hit the doctor blade when the coating liquid is scraped off by the doctor blade. In the gravure coating apparatus according to claim 1,
The thickness t1 of the doctor blade is such that the interval in the rotation direction of the plate cylinder at two adjacent projections among the projections is D1, the extension direction of the rotation axis of the plate cylinder is the extension direction of the plate cylinder. A gravure coating apparatus, wherein t1 ≧ D1 × sin θ is set so that the angle of the doctor blade with respect to the outer peripheral surface is θ. In the gravure coating apparatus according to claim 1 or 2,
The doctor blade has an acute angle with respect to the outer peripheral surface of the plate cylinder as viewed from the extension direction of the rotation axis of the plate cylinder so that the tip thereof is directed in the opposite direction to the rotation direction of the plate cylinder. A gravure coating apparatus, wherein the gravure coating apparatus is in contact with the outer peripheral surface of the plate cylinder so as to be in a posture. In the gravure coating device according to any one of claims 1 to 3,
Of the two protrusions adjacent to each other in the rotation direction of the plate cylinder, the position of the protrusion on the downstream side in the rotation direction with respect to the protrusion on the upstream side in the rotation direction is one end side of the rotation axis with respect to the rotation direction of the plate cylinder. The gravure coating apparatus is set so that the angle is shifted by 0 ° <θ ≦ 1 °. In the gravure coating device according to any one of claims 1 to 4,
The gravure coating is characterized in that the ratio of the total total area of the opening portions of the first oblique line groove portions and the second oblique line groove portions to the total area of the outer peripheral surface of the plate cylinder is set to 90% or more. Engineering equipment.

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