JP2004058579A - Plate cylinder structure of rotary printing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plate cylinder structure of a rotary printing machine which holds a uniform printing pressure on printing paper and maintains the precision of printing at a high level. <P>SOLUTION: The rotary printing machine wherein printing is conducted by passing the printing paper P between a plate cylinder 15 and an impression cylinder 16 has the plate cylinder structure wherein paired ring-shaped members 27 are disposed around a support shaft 25 of the plate cylinder 15, with a plate cylinder 20 held between. These ring-shaped members 27 are so provided as to have a diameter substantially equal to that of the plate cylinder 15 in a state wherein a press plate 26 is mounted thereon, and they prevent a phenomenon of bounding on the impression cylinder 16 due to a relief bias or others of the press plate 26. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plate cylinder structure of a rotary printing press, and more particularly, to a plate cylinder structure of a rotary printing press suitable for preventing undesired shading or the like from appearing on a printing surface due to a bouncing phenomenon of the plate cylinder.
[0002]
[Prior art]
In a rotary printing press such as a flexographic printing press, an ink pan is provided for each of a plurality of printing units, and a printing plate in which ink contained in the ink pan is mounted on an outer periphery of a plate cylinder via a fountain roll and an anilox roll. (Printing plate). Then, when a printing paper continuous in a band shape passes between the plate cylinder and the impression cylinder facing the printing cylinder, predetermined printing is performed on the printing paper.
[0003]
[Problems to be solved by the invention]
In a known printing unit, a printing plate is fixed to the outer periphery of a plate cylinder via a double-sided tape, and a printing pressure required for printing is applied to printing paper passing between the printing cylinder and the printing cylinder. . Since this printing pressure adjustment is performed on both sides of the plate cylinder in the axial direction, it is very difficult to maintain the printing pressure distribution on the printing cylinder evenly and to adjust the proper printing pressure of the printing plate. is there. In particular, a decrease in printing accuracy due to excessive application of printing pressure often appears remarkably. This is due to the fact that printing cannot be performed in the state where printing pressure is not applied, so it is easy for workers to visually recognize insufficient pressure, while excessive printing pressure cannot be grasped without being enlarged and confirmed with a loupe or the like. I do.
[0004]
In addition, since the contact distribution with the printing paper is usually not uniform due to variations or deviations in the relief distribution of the printing plate, seams of the printing plate, etc., the printing plate is in a direction orthogonal to the axial direction of the plate cylinder. Phenomena tend to occur, which leads to the inconvenience of appearing as intermittent and regular stripes on the printed surface.
[0005]
[Object of the invention]
The present invention has been made in view of such inconveniences, and an object thereof is to provide a printing press for a rotary printing press capable of maintaining printing pressure on printing paper uniformly and maintaining high printing accuracy. It is to provide a torso structure.
[0006]
Another object of the present invention is to provide a plate cylinder structure of a rotary printing press that can simplify initial setting work such as adjustment of printing pressure.
[0007]
Still another object of the present invention is to provide a plate cylinder structure of a rotary printing press that can easily cope with a proper printing pressure even when the thickness of printing paper is changed.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention relates to a plate cylinder structure of a rotary printing press that performs printing on a printing sheet by passing a printing sheet between a plate cylinder and an impression cylinder,
A configuration is adopted in which a bounce prevention means is provided on the outer peripheral side of the plate cylinder. According to such a configuration, it is possible to effectively prevent the printing plate from bouncing, that is, vibrating in a direction perpendicular to the axial direction of the plate cylinder, and there is a bias such as a relief of the printing plate. However, it is possible to maintain the printing pressure evenly along the axial direction of the plate cylinder, thereby enabling high-precision printing.
[0009]
Further, the bounce prevention means is constituted by a pair of ring-shaped members arranged around a support axis of the plate cylinder on both sides of the plate cylinder, and the ring-shaped member comes into contact with the impression cylinder side. I am taking it. With this configuration, the printing pressure can be maintained uniformly along the axial direction of the plate cylinder. For example, when a printing plate having a different relief for each printing unit is used, such as a flexographic printing press. However, it is possible to equalize the printing pressure for each unit.
[0010]
Further, the diameter of the ring-shaped member is substantially equal to the diameter of the plate cylinder when a printing plate is mounted on the plate cylinder. Thus, the state in which the ring-shaped member is in contact with the impression cylinder can be set as the maximum contact pressure, so that the setting by visual inspection can be easily realized, and the initial setting operation of the printing apparatus can be performed easily and quickly.
[0011]
In the present invention, it is preferable that the ring-shaped member is detachably provided. With such a configuration, even when the thickness of the printing paper is changed, it is possible to cope with the problem simply by replacing the printing paper with a ring-shaped member having a different diameter, and versatility can be provided.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which a plate cylinder structure of a rotary printing press according to the present invention is applied to a printing unit of a flexographic printing press will be described.
[0013]
FIG. 1 is a schematic side view of a printing unit of a flexographic printing press according to the present embodiment. In this figure, a printing unit 10 includes a fountain roll 12 disposed so that an outer peripheral surface portion is immersed in an ink pan 11 containing ink I, an anilox roll 13 in contact with the outer peripheral surface of the fountain roll 12, and an anilox roll A printing cylinder P is formed of a plate cylinder 15 to which the ink I is transferred via the printing cylinder 13 and an impression cylinder 16 facing the plate cylinder 15, and the band-shaped printing paper P is passed between the impression cylinder 16 and the plate cylinder 15. Thus, predetermined printing can be performed.
[0014]
As shown in FIG. 2, the plate cylinder 15 includes a plate cylinder 20, stepped bearings 21 and 21 fixed to both axial ends of the plate cylinder 20, and inner circumferences of the stepped bearings 21 and 21. And a support shaft 25 fixed via bearings 23, 23, and a printing plate 26 is wound around the outer peripheral surface of the plate cylinder 20 via a double-sided tape T.
[0015]
In the stepped bearings 21 and 21, ring-shaped members 27 and 27 constituting a bounce prevention means are arranged on the outer periphery of each of the small diameter portions 21A and 21A. The shape members 27, 27 are in a state of being arranged in a pair on the left and right. The ring-shaped members 27, 27 are detachably fixed to the outer surfaces of the large-diameter portions 21B, 21B of the stepped bearing 21 by screws 28 disposed at intervals of approximately 120 degrees in the circumferential direction (FIG. 1). reference). The diameter D1 of the ring-shaped member is set to a size substantially equal to the diameter D2 of the plate cylinder 15 in a state where the printing plate 26 is wound around the plate cylinder 20.
[0016]
The impression cylinder 16 has cylinders 30, bearings 31, 31 located at both ends of the cylinder 30 and having diameter portions substantially equal to the diameter of the cylinder 30, and penetrates the cylinder 30 and the bearing 31. A support shaft 33 is provided so that the outer peripheral surface of the ring-shaped member 27 contacts the outer peripheral surface of the bearings 31.
[0017]
In the plate cylinder 15 and the impression cylinder 16, gears (not shown) are fixed to one ends of their support shafts, and these gears are incorporated into the printing unit 10 in a state of meshing with each other. I have.
[0018]
Next, the overall operation of the printing unit 10 will be described. Here, it is assumed that the ring-shaped member 27 corresponding to the thickness of the printing paper P is set to be in contact with the outer peripheral surface of the bearing 31 in the impression cylinder 16.
[0019]
When the fountain roll 12 is rotated by a predetermined power supply, the ink I is transferred to the plate cylinder 15 via the anilox roll 13, and the printing paper P passing between the plate cylinder 15 and the impression cylinder 16 is printed on a printing plate 26. Will be printed in accordance with the relief. At this time, the reliefs of the printing plate 26 are not usually in the same distribution state, and the plate 26 itself tends to bounce in a direction perpendicular to the axial direction due to the elasticity of the printing plate 26 or the bias of the relief. However, in the present embodiment, as described above, the diameter D1 of the ring-shaped member 27 is substantially equal to the diameter D2 of the plate cylinder 20 including the printing plate 26, and the outer peripheral surface of the ring-shaped member 27 is Because it is in contact with the outer peripheral surface of the bearing 31, the vibration in the direction to be bound can be physically restricted. Accordingly, the printing plate 26 comes into contact with the impression cylinder 16 with substantially equal printing pressure over the entire circumference thereof, and the printing paper P passing between the printing plate 26 and the impression cylinder 16 has shading caused by a change in printing pressure. No bound phenomenon occurs.
[0020]
Therefore, according to such an embodiment, by simply providing the ring-shaped member 27 in the existing equipment, it is possible to prevent the plate from bouncing, and to perform extremely accurate printing without a cost burden. It becomes possible.
[0021]
In the above embodiment, the case where the ring-shaped member 27 is arranged so as to be in contact with the outer peripheral surface of the bearing 31 of the impression cylinder 16 has been described, but the present invention is not limited to this. For example, the impression cylinder 16 may be provided with a similar ring-shaped member that is detachable, and may be configured to be in mutual contact with the ring-shaped member 27 on the plate cylinder 20 side. In short, the present invention does not prevent various design changes as long as the plate 26 can suppress the bouncing phenomenon of vibrating in the direction substantially perpendicular to the axis of the plate cylinder 20.
[0022]
【The invention's effect】
As described above, according to the present invention, the bounce prevention means is provided on the outer peripheral side of the plate cylinder, so that the plate is effectively prevented from bouncing even if there is unevenness in the relief of the printing plate or elastic deformation. As a result, the printing pressure can be maintained uniformly along the axial direction of the plate cylinder, and printing on printing paper can be performed with high accuracy.
[0023]
Further, since a pair of ring-shaped members are arranged around the support shaft of the printing plate at both sides of the plate cylinder to constitute the bounce prevention means, a uniform printing pressure along the axial direction of the plate cylinder is maintained. be able to.
[0024]
Further, by making the diameter of the ring-shaped member constituting the bounce prevention means substantially equal to the diameter of the plate cylinder in a state where the printing plate is mounted on the plate cylinder, it is possible to avoid the difficulty of the conventional printing pressure adjustment, The visual setting and the initial setting of the printing apparatus can be easily performed.
[0025]
In addition, according to the configuration in which the ring-shaped member is detachably provided, even when the thickness of the printing paper is changed, it is possible to easily cope with the change by simply replacing the ring-shaped member with a different diameter. Versatility can be imparted, such as being applicable to an apparatus.
[Brief description of the drawings]
FIG. 1 is a schematic side view showing a printing unit of a flexographic printing press to which the present invention is applied.
FIG. 2 is an enlarged partial cross-sectional plan view showing a plate cylinder and an impression cylinder.
[Explanation of symbols]
Reference Signs List 10 printing unit 15 plate cylinder 16 impression cylinder 20 plate cylinder 25 support shaft 26 plate 27 ring-shaped member (bound prevention means)
D1 Diameter D2 Diameter P Printing paper T Double-sided tape

Claims (4)

In a plate cylinder structure of a rotary printing press that performs printing on the printing paper by passing the printing paper between the plate cylinder and the impression cylinder,
A plate cylinder structure for a rotary printing press, characterized in that said plate cylinder is provided with a bounce prevention means. The said bounce prevention means is comprised by a pair of ring-shaped members arrange | positioned around the support axis of the said plate cylinder on both sides of the said plate cylinder, The said ring-shaped member contacts the said impression cylinder side, The Claims characterized by the above-mentioned. Item 2. A plate cylinder structure of a rotary printing press according to Item 1. The plate cylinder structure of a rotary printing press according to claim 2, wherein a diameter of the ring-shaped member is substantially equal to a diameter of the plate cylinder when a printing plate is mounted on the plate cylinder. The plate cylinder structure of a rotary printing press according to claim 2, wherein the ring-shaped member is provided detachably.

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