JP3294162B2 - Shock mark prevention device for printing press - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock mark preventing device for a printing press for preventing a shock mark on printing paper which is generated during offset printing.

[0002]

2. Description of the Related Art In a printing cylinder such as a plate cylinder and a blanket cylinder in offset printing, a plate material of a flat metal plate or a rubber blanket is wrapped around its periphery. The ends of these rubber blankets and the like are clamped and fixed in clamp grooves formed along the axis of each body.
Therefore, these clamping grooves meet each other at one rotation at the contact between the plate cylinder and the blanket cylinder, or between the blanket cylinder and the blanket cylinder, which are in contact with each other.

[0003]

By the way, during the printing operation, the cylinders rotate while contacting each other with a constant pressure. Therefore, in the state where the clamp groove is not located at the contact between the cylinders during printing, the contact pressure acts between the cylinders in contact with each other, but when the clamp groove meets the contact at the contact, the contact pressure is released. . That is, the external force acting on the printing cylinder fluctuates periodically. This contact pressure drop occurs because the radius of the clamp groove of each cylinder is slightly reduced, and is inevitably generated in offset printing. Therefore, vibration occurs due to a shock when the grooves meet each other every rotation of the printing cylinder, and this vibration is transferred as a shock mark to the printed matter, causing "unevenness" in the printed pattern. Adversely affect print quality and cause poor printing, thereby deteriorating print quality.

Therefore, a printing machine (double cylinder) in which the diameter of the printing cylinder is increased to suppress the vibration is manufactured, but in this case, there is a problem that the manufacturing cost is increased. Although a method of reducing the vibration of each printing cylinder with an attenuation member or a damper has been proposed, it is difficult to always effectively attenuate the vibration at different printing speeds because the vibration includes many frequency components. It is. Furthermore, printing machines that use a seamless plate or a seamless blanket have been proposed to eliminate the clamping groove of the vibration source.However, the production cost of the plate or the blanket increases, and as the printing progresses, the blanket is attached to the printing cylinder. On the other hand, there is a problem that the printing quality is gradually degraded and the printing quality is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for preventing a shock mark of a printing press, which can reduce printing unevenness by suppressing the occurrence of periodic vibration of a printing cylinder and improve printing quality. is there.

[0006]

According to the present invention, there is provided a device for applying a force to the inside or outside of a printing cylinder, and a periodic release of contact pressure occurs between clamp grooves of the cylinder which is a vibration source of the printing cylinder. In accordance with the cycle, a force corresponding to the released contact pressure is applied to the printing cylinder to reduce vibration, thereby reducing printing unevenness and improving print quality.

Specifically, according to the first aspect of the present invention, there is provided a shock-mark preventing device for a printing press, wherein the device is provided on a surface of a plurality of printing cylinders which rotate in reverse contact with each other at a predetermined contact pressure. Clamp grooves for clamping a plate or a rubber blanket are formed in parallel with the axis, respectively. The shock of a printing press that suppresses the fluctuation of contact pressure generated when the clamp grooves meet with the rotation of these printing cylinders. A mark preventing device, characterized in that it has a pressing means for pressing these printing cylinders to the opposite side of the clamping grooves in accordance with the cycle at which the clamping grooves for rotation of the printing cylinders meet.

In the above, the printing cylinder refers to a plate cylinder, a blanket cylinder, or the like, and the pressing means may be of any type as long as it presses the printing cylinder to the opposite side of the groove. It is not limited to a pneumatic type, an electric type or the like. Further, the pressing force is the sum of the force by the reaction force bar in the clamp groove association state and the force by the contact pressure of the printing cylinder is almost equal to the force acting on the printing cylinder in the normal contact state other than the clamp groove association state. It is preferable that the strength be the same. Also,
It is preferable that the pressing means is on the opposite side of the clamp groove by 180 degrees with respect to the reaction force bar.

In the present invention, since each printing cylinder presses the opposite side of the clamp groove by the pressing means when the respective clamp grooves meet, the contact pressure reduced at the contact point between the clamp grooves is compensated. The sum of the force from the reaction bar and the force due to the contact pressure of the printing cylinder in the clamp groove association state is the same as the force acting on the printing cylinder in the normal contact state other than the clamp groove association state. can do. Therefore, the fluctuation of the contact pressure of the printing cylinder is eliminated, the occurrence of vibration is suppressed, and the printing unevenness is reduced, so that the printing quality can be improved.

According to a second aspect of the present invention, there is provided an apparatus for preventing a shock mark of a printing press, wherein each of the printing cylinders according to the first aspect is rotatably supported by a bearing and is provided at both ends of the cylinder. A trunk body comprising a journal formed with a diameter smaller than the trunk portion, bearers mounted on both ends of the trunk portion of the trunk body, and a reaction bar mounted on an axis of the trunk body. The pressing means is characterized by being a fluid actuator including a cylinder and a piston mounted inside the trunk body and pressing the trunk body outward against the reaction bar. In the present invention, since the fluid actuator accurately and easily controls and presses the opposite side of the clamp groove when the clamp groove meets, vibration of the printing cylinder is suppressed, and printing unevenness is reduced. As a result, the print quality can be improved.

According to a third aspect of the present invention, there is provided an apparatus for preventing a shock mark of a printing press, comprising: a hydraulic pump provided outside a printing cylinder;
One end is opened along the axis line inside the shaft body via a rotary joint and connected to a hydraulic hole communicating with the cylinder, and the other end is connected to a hydraulic pump, and is provided in the middle of the hydraulic piping. A servo valve that sends the pressure oil of the hydraulic pump to the cylinder, a detector that is provided outside each printing cylinder, detects the position of the clamp groove of the printing cylinder, and transmits the signal, and a signal from this detector. And a control device for issuing a command to the servo valve so that the pressure oil from the hydraulic pump becomes equal to a preset pressing force. According to the present invention, since the fluid actuator accurately and easily controls the cylinder body and presses the cylinder body against the opposite side of the clamp groove when the clamp groove meets, fluctuations in the vibration of the printing cylinder are suppressed and printing unevenness is suppressed. , Thereby improving the print quality.

According to a fourth aspect of the present invention, there is provided an apparatus for preventing a shock mark of a printing press, comprising the steps of:
A torso body rotatably supported by a bearing, bearers attached to both ends of the torso of the torso body, and a reaction force bar attached to the shaft center of the torso body are formed to have a pressing means. ,
It is an electromagnetic force actuator including a magnetic pole attached to the inside of the trunk body and attracting the trunk body to the axial center side with respect to the reaction force bar. According to the present invention, since the cylinder body is suctioned in the opposite direction of the clamp groove when the clamp groove meets with accurate and easy control by the electromagnetic force actuator, vibration of the printing cylinder is suppressed, and printing unevenness is suppressed. As a result, the print quality can be improved with a simple configuration.

According to a fifth aspect of the present invention, there is provided an apparatus for preventing a shock mark of a printing press according to the fourth aspect, wherein the electromagnetic force actuator according to the fourth aspect includes a coil provided around a magnetic pole and one end connected to the coil. On the other end side, the wires extending from the wiring hole formed along the axis line inside the shaft body to the outside of the shaft body via the slip ring, and the positions of the clamp grooves of the printing cylinder provided outside each printing cylinder are described. It is characterized by comprising a detector for detecting and transmitting the signal, and a control device for generating an electromagnetic force based on a signal from the detector, the electromagnetic force being equal to a preset attractive force for the coil. It is assumed that. According to the present invention, since the cylinder body is suctioned in the opposite direction of the clamp groove when the clamp groove meets with accurate and easy control by the electromagnetic force actuator, vibration of the printing cylinder is suppressed, and printing unevenness is suppressed. As a result, the print quality can be improved with a simple configuration.

According to a sixth aspect of the present invention, there is provided an apparatus for preventing a shock mark of a printing press according to the first aspect, wherein the pressing means applies external pressure to each printing cylinder. An external pressure applying device is characterized. In the above, as the external pressure applying device, a device that does not affect the printing pattern on the surface of the printing cylinder by a non-contact actuator such as an air blowing device or an electromagnet is preferable. If it is not possible to press the side, it may be pressed in a slightly displaced direction to prevent fluctuations in the force acting on the body and suppress vibration. In the present invention, since a force is externally applied to the printing cylinder,
It is not necessary to provide a cylinder or the like inside the printing cylinder, and the structure is simplified.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 3, a shock mark preventing device 1 for a printing press according to a first embodiment of the present invention includes:
The printing cylinder is pressed against the opposite side of the clamp groove 12A by the pressing means 2 using a fluid actuator.

First, the printing cylinder 10 of the present embodiment will be described. The printing cylinder 10 includes a cylinder main body 12 including a cylinder and journal portions formed at both ends of the cylinder with smaller diameters than the cylinder.
And bearers 9 attached to both ends of the body of the body 12
And a reaction bar 11 inserted at the center of the cylinder main body 12. The blanket 14 or the print 44 is wound around the outer periphery of the barrel of the printing cylinder 10. The journal portion is formed in a stepped shape with a small diameter, and a portion of the journal portion having a minimum diameter is supported by the bearing 13. Therefore, the printing cylinder 10 is freely rotatable.

A hole 12B having an inner diameter larger than the outer dimensions of the reaction force bar 11 is formed between the inside of the trunk main body 12 and a portion inside the end from the predetermined dimension.
As a result, a gap C having a predetermined dimension is provided between the reaction force bar 11 and the inner diameter of the body 12. A single clamp groove 12A is formed on the outer periphery of the body 12 along the axis thereof, and the end of the rubber blanket 14 or the print 44 is clamped and fixed to the clamp groove 12A. I have.

A hydraulic hole 15 is formed at the axial center of the reaction bar 11 over the entire length of the reaction bar 11. A cylinder 16 is provided inside the reaction bar 11 at right angles to the axis of the reaction bar 11 and substantially 180 degrees opposite to the clamp groove 12A.
It has a piston 17 that can move in and out in a direction perpendicular to the axis. In addition, a plurality of reaction force bars 11 are arranged at predetermined intervals in the length direction. And these cylinders 16
And the hydraulic hole 15 are connected by a connection hole 15A. Here, when the piston 17 of the cylinder 16 comes out, its tip comes into contact with the inner diameter 12B of the body 12, and the body 12 is clamped against the reaction force bar 11 by the clamp groove 12B.
A can be pressed 180 degrees outward of A.

A rotary joint 18 is attached to an end face of the reaction force bar 11, and one end of a hydraulic pipe 20 whose other end is connected to a hydraulic pump 19 is connected to the rotary joint 18. A servo valve 21 that supplies pressure oil from a hydraulic pump 19 to the cylinder 16 is disposed in the middle of the hydraulic pipe 20. The dog 2 is fixed to the outer periphery of the trunk body 12 on the side opposite to the clamp groove 12A by, for example, 180 degrees.
2, a frame 23 (not shown) is provided with a detector 23 for detecting the position of the dog 22.
As shown in FIG. 3, the detector 23 includes a printing cylinder (rubber cylinder on which a rubber blanket 14 is mounted) 10A, 10A, or a printing cylinder 10A and 10B (a printing cylinder on which a print 44 is mounted) which are in contact with each other. ) Output a signal at a timing at which the clamp grooves 12A meet at the contact point.

A control device 24 is provided outside the printing cylinder 10.
When the controller 24 receives the signal of the clamping groove association from the detector 23, the controller 24 issues a command to the servo valve 21 to supply the cylinder 16 with pressure oil for compensating for the loss of the contact pressure. It has become. In addition, the force for the release of the contact pressure obtained by a means such as an actual measurement is set in advance. Here, the fluid actuator 2 is configured to include each member represented by a series of consecutive reference numerals from the hydraulic pressure hole 15 to the control device 24, and the fluid actuator 2 serves as the pressing means.

Next, based on FIG. 3, two such printing cylinders 10 are arranged above and below each other across a web W which is a continuous printing paper, and are used for duplex printing. The relationship of the forces acting on is described. The blanket cylinders 10A and 10A of the printing cylinder are arranged above and below the web W in contact with each other with a predetermined contact pressure, and the plate cylinders 10B and 10B contact with the respective blanket cylinders 10A and 10A with a predetermined contact pressure. It is arranged. Therefore, the printing cylinders 10 that are in contact with each other
Between A and 10A and between 10A and 10B, a contact pressure acts at a contact point in a direction for separating one body from the other body.

That is, when the two printing cylinders 10A, 10A, etc. are rotating while pressing against each other, the respective cylinders 10A are pushed from the other side and are bent by receiving a load over the entire length of the cylinder. . The amount of deflection is determined by the trunk diameter, the length of the trunk, the diameter of the journal part of the trunk, and the trunk pressure (the pressing pressure between the trunks), but is approximately several mm / 100.

At the rotation angle at which the clamp grooves 12A associate with each other at the contact point, the radius of the clamp groove 12A is slightly reduced, so that the contact pressure is released and the contact pressure is reduced. The amount of flexure fluctuates (decreases) at the time of groove association. However, at this time, the piston 17 of the cylinder 16 provided on the reaction force bar 11 presses the body 12 to the side opposite to the clamp groove 12A by 180 degrees by the clamp groove association signal from the detector 23, and the contact pressure is reduced. The applied force is applied to each of the printing cylinders 10A and 10A, so that the sum of the forces acting on the printing cylinders 10A and 10A is in the other state even in the clamp groove association state, that is, the clamp grooves 12A are associated with each other. So that it is the same as when it is not. Therefore, the force acting on the printing cylinders 10A and 10A does not fluctuate periodically, whereby fluctuations in vibration can be suppressed and printing unevenness due to vibration can be prevented.

A plate 44 is mounted on the body 42 of the plate cylinder 10B of the printing cylinder, and an end of the plate 44 is clamped and fixed in a clamp groove 42A. Further, pressing means including a cylinder and the like may be provided on the plate cylinder 10B.

According to this embodiment, the following effects can be obtained. When the clamp groove 12A is in the associated state, the reaction bar 1
1 and the force due to the contact pressure between the printing cylinders 10 are the same as the force acting on the printing cylinder 10 in a normal contact state other than the associated state of the grooves 12A. Will not always fluctuate.
Therefore, the fluctuation of the vibration of the printing cylinder 10 is suppressed, and the printing unevenness is eliminated, so that the occurrence of the shock mark can be prevented, and the printing quality can be improved.

A dog 22 is provided on the outer periphery of the journal portion of the cylinder main body 12, while a detector 23 for detecting the position of the dog 22 is provided on the frame of the printing press, and a clamp groove from the detector 23 is provided. Since a suitable amount of pressure oil is supplied to the cylinder 16 by the control device 24 in response to the detection signal, the force can be applied to the body 12 accurately. Since there are a plurality of cylinders 16 provided inside the body 12 at predetermined intervals in the longitudinal direction of the body 12,
2 can be evenly pressed against the reaction bar 11, whereby the force acting on the printing cylinder 10 does not fluctuate, thereby preventing vibration and eliminating printing unevenness, thereby improving print quality. .

FIGS. 4 to 6 show a second embodiment of the present invention. In the shock mark preventing device 1 'for a printing press according to this embodiment, the pressing means 2 of the first embodiment uses a fluid actuator. On the other hand, the body 12 is pressed (sucked) to the opposite side of the clamp groove 12A with respect to the reaction force bar 11 by a pressing means 2 'using an electromagnetic force actuator. Therefore, in this embodiment, only the portions different from the first embodiment will be described, and the first embodiment will be described.
The same reference numerals are given to the same structures, members, and the like as those in the embodiment, and the detailed description is omitted or simplified.

Inside the reaction bar 11, a wiring hole 15 'is formed along its axis, and a magnetic pole 30 and a coil 31 are provided in place of the cylinder 16. The magnetic pole 30 and the coil 31 are arranged orthogonal to the wiring hole 15 ′ and on the same side as the clamp groove 12A, and the magnetic pole 30 faces the inner diameter 12B of the body 12 with a gap.

One end of the coil 3 is inserted into the wiring hole 15 '.
1 and the other end of the electric wire 32 connected to the control device 24 'are inserted.
Are connected by A slip ring 33 is provided at an end of the reaction bar 11. The control device 24 ′ is configured to output a current for generating an electromagnetic force having a preset contact pressure compensation pattern to the coil 31 when receiving the signal of the clamp groove association from the detector 23. Accordingly, by outputting a current to the coil 31, the magnetic pole 30 operates to attract the clamp groove 12A of the body 12 to the reaction force bar 11, thereby reducing the contact pressure when the clamp grooves 12A are associated with each other. By compensating for the amount of force applied, the fluctuation of the force acting on the printing cylinder is prevented, and the occurrence of vibration is suppressed.

When the printing cylinder 10 with the shock mark prevention device 1 'using such an electromagnetic force actuator is arranged as shown in FIG. 6, the same force action as in the first embodiment is applied to each cylinder 10A. Work between 10A etc. However,
In the first embodiment, the trunk body 12 is pressed against the reaction bar 11, and in the second embodiment, there is a difference in that the trunk body 12 is sucked toward the reaction bar 11, but as a result, The force acts on the opposite side of the clamp groove 12A, and the effect is the same. In this embodiment, the same operation and effect as described above can be obtained.

The present invention is not limited to the above embodiments, and includes the following modifications as long as the objects of the present invention can be achieved. That is,
In each of the above embodiments, the pressing means 2, 2 ′ is
Of the printing cylinder 10 as shown in FIG.
A, a force may be applied from the outside of 10A by a non-contact type actuator.

In the example of FIG. 7, two printing cylinders 10A, 10A
When A and 10A and 10B are in contact with each other, a printing cylinder 10B without a clamp groove and a printing cylinder 1 with a clamp groove 12A
0A are always in contact with a constant pressure, and the printing cylinder 10
Variations in the forces acting on A, 10A are caused by the clamping groove 12A in the trunk with the bearer. Accordingly, a force substantially equivalent to the variation (decrease) of the pressing force at the time of the groove association is applied to the cylinder body 12.
In this case , the deflection amount of the body is not changed as a result.

More specifically, if the cylinder main body 12 cannot be pressed 180 degrees opposite to the clamp groove 12A due to the arrangement of the printing cylinders, for example, an air blowing device or an electromagnet And the like, so that the direction of the resultant force F of the two is 180 degrees opposite to the clamp groove 12A. In this embodiment, in addition to the same effects as those of the above-described embodiments,
Since a force can be applied from the outside of the printing cylinder 10A, there is no need to provide a reaction force bar or the like inside the cylinder main body 12, and
This has the effect of simplifying the structure and facilitating manufacture.

Further, in each of the above embodiments, the shock marks are prevented between the printing cylinders 10A and 10A which are in contact with each other. However, the present invention is not limited to this, and the present invention can be applied between the printing cylinders 10A and 10B. is there. In this case, the printing cylinder 1
0B is provided with the same pressing means or the like as the pressing means 2 or 2 'to have the same structure as the printing cylinder 10A, and the pressing means of the printing cylinder 10A is such that the grooves of both printing cylinders 10A and 10B meet. At this time, it may be configured such that the opposite side of the clamp groove can be pressed.

[0035]

As described above, according to the apparatus for preventing a shock mark of a printing press according to the present invention, the press cylinder presses the opposite side of the clamp groove by the pressing means when the clamp grooves meet. Compensating for the decrease in the force on the printing cylinder due to the reduction of the contact pressure at the contact between the clamp grooves, the sum of the force from the reaction bar and the force due to the contact pressure of the printing cylinder when the clamp groove is in association, In the case of a normal contact state other than the groove association state, the force acting on the printing cylinder can be the same. Accordingly, since the force acting on the printing cylinder does not fluctuate periodically, vibration can be prevented, and printing unevenness due to vibration can be prevented, thereby improving print quality.

[Brief description of the drawings]

FIG. 1 is an overall view showing a shock mark preventing device for a printing press according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a diagram illustrating a contact state between grooves of a printing cylinder according to the first embodiment.

FIG. 4 is an overall view showing a shock mark prevention device for a printing press according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line VV in FIG. 4;

FIG. 6 is a diagram illustrating a contact state between grooves of a printing cylinder according to the second embodiment.

FIG. 7 is a view showing a shock mark preventing device for a printing press according to a modified embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1 'Shock mark prevention device of printing press 2, 2' Pressing means 9 Bearer 10 Printing cylinder 11 Reaction force bar 12 Body 12A Clamp groove 16 Cylinder 19 Hydraulic pump 21 Servo valve 24, 24 'Control device 30 Magnetic pole 31 Coil 32 electric wires

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41F 13/20 B41F 7/02 B41F 33/08

Claims (6)

(57) [Claims] 1. A printing machine comprising: a plurality of printing cylinders which are rotated in contact with each other at a predetermined contact pressure to form a clamping groove for clamping a printing plate or a rubber blanket in parallel with an axis of the printing cylinder; A shock mark preventing device for a printing press, which suppresses a variation in contact pressure generated when the clamp grooves meet with the rotation of the printing cylinder, wherein the clamp grooves of the rotation of the printing cylinders associate with each other. And a press means for pressing these printing cylinders to the opposite side of said clamp groove. 2. The apparatus according to claim 1, wherein each of the printing cylinders is rotatably supported by a bearing and is formed at both ends of the drum with smaller diameters than the drum. A torso body consisting of a journal part
Bearers attached to both ends of the trunk of the trunk body,
And a reaction force bar mounted on an axis of the trunk body, wherein the pressing means is mounted inside the trunk body and presses the trunk body outward against the reaction force bar; and A shock mark preventing device for a printing press, characterized by being a fluid actuator including a piston. 3. The shock mark prevention device for a printing press according to claim 2, wherein the fluid actuator includes a hydraulic pump provided outside the printing cylinder and one end inside the shaft main body via a rotary joint. A hydraulic pipe opened along an axis and connected to a hydraulic hole communicating with the cylinder, and having the other end connected to the hydraulic pump; A servo valve which is provided outside each of the printing cylinders, detects a position of a clamp groove of the printing cylinder, and transmits a signal indicating the position of the clamp groove. A control device for issuing a command to the servo valve so as to make the pressure oil equal to a preset pressing force. Mark prevention device. 4. A shock mark preventing device for a printing press according to claim 1, wherein each of said printing cylinders is mounted on both ends of a cylinder main body rotatably supported by a bearing and a body of said cylinder main body. Bearing body, and a reaction bar mounted on the axis of the trunk body, wherein the pressing means is mounted in the trunk body and moves the trunk body with respect to the reaction bar. A shock mark preventing device for a printing press, characterized in that the device is an electromagnetic force actuator including a magnetic pole attracting to a side. 5. The shock mark preventing device for a printing press according to claim 4, wherein the electromagnetic force actuator comprises:
A coil provided around the magnetic pole, one end of which is connected to the coil and the other end of which extends from a wiring hole formed inside the shaft main body along the axis thereof to the outside of the shaft main body via a slip ring. An output wire, a detector provided outside each of the printing cylinders for detecting a position of a clamp groove of the printing cylinder and transmitting the signal, and a coil which is set in advance in the coil based on a signal from the detector. And a control device for generating an electromagnetic force that is equal to the suction force of the printing press. 6. A shock mark for a printing press according to claim 1, wherein said pressing means is an external pressure applying device for applying pressure to said printing cylinders from outside. Prevention device.