JP2002240236A - Auxiliary apparatus for registering plate cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an auxiliary apparatus for registering a plate cylinder by which registering of the plate cylinder can be supported and the position of the plate cylinder can be precisely adjusted without requiring experienced skill. SOLUTION: An eccentric sleeve 17 for freely rotatably supporting the shaft 14 of the plate cylinder 6 at an eccentric position and freely movably supporting in the shaft direction to a frame 15 and a slide member 31 for supporting the shaft 14 so as to freely adjust the position in the rotational direction are provided and the eccentric sleeve 17 is freely adjustably constituted by means of a shaft direction adjusting mechanism and is freely adjustably constituted by means of a peripheral direction adjusting mechanism and the shaft 14 is constituted so as to freely approach and separate from to a rubber blanket cylinder 8 by means of a plate pressure adjusting mechanism and a position detecting sensor SX for detecting amount of movement in the shaft 14 direction of a guide member 25 provided on the eccentric sleeve 17, a position detecting sensor SY for detecting displacement in the rotational direction of a guide member 25 and a position detecting sensor SZ for detecting displacement of a disc 30 provided on the slide member 31 are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a registration assisting device for a plate cylinder which facilitates registration when the plate cylinder is positioned with respect to a blanket of a blanket cylinder.

[0002]

2. Description of the Related Art A so-called two-piece can comprises a can lid and a cylindrical can body. The can body is subjected to DI (deep drawing, ironing) processing and washing, and thereafter the outer surface thereof is printed. . As shown in FIG. 7, the can printing apparatus A has an ink attaching mechanism B
And a can moving mechanism C. Ink adhesion mechanism B
Is composed of an inker unit 1 that supplies ink, and a blanket cylinder 8 that contacts the inker unit 1 to copy the ink and then contacts the can body 10 to print the ink.

The inker unit 1 includes an ink source 2, a ducting roll 3, an intermediate roller 4, and a rubber roller 5.
, And a plate cylinder (plate cylinder) 6, which are in contact with each other so as to sequentially receive ink from the ink source 2. On the outer peripheral surface of the blanket cylinder 8,
A plurality of blankets 7 are provided. The blanket 7 is configured to be in rolling contact with a plate (not shown) formed on the outer peripheral surface of the plate cylinder 6 and is also in rolling contact with the can body 10. The can moving mechanism C sequentially includes a can shooter 9 that takes in the can body 10, a mandrel 11 that rotatably holds the can body 10 supplied from the can shooter 9, and a can body 10 attached to the mandrel 11, in order. Mandrel turret 1 that rotates and moves in the direction of the ink attachment mechanism B
It consists of two.

In the can printing apparatus A, inks of different colors from the respective ink sources 2 are supplied via the ducting roll 3, the intermediate roller 4 and the rubber roller 5, respectively.
Each color ink adheres to the plate of each plate cylinder 6, and the ink of each color is applied as an image on the blanket 7, and the image is printed while contacting the can body 10 held on the mandrel 11. The mandrel turret 12 is provided with an application mechanism D for applying a transparent overburnish to the surface of the can 10 after the transfer.

Here, the plate cylinder 6 transfers an image to a blanket 7 of a blanket cylinder 8, and the transferred image is printed on a can 10 mounted on a mandrel 11 of a mandrel turret 12. Therefore, a position adjusting device 13 for the plate cylinder 6 as shown in FIG. Position adjustment device 13
6, as shown in FIG. 6, the axial direction of the plate cylinder 6 (in FIG.
And the direction in which the plate cylinder 6 is moved toward and away from the blanket cylinder 8 to adjust the plate pressure. For the sake of simplicity, the axial direction of the plate cylinder 6 will be referred to as "X direction", the circumferential direction of the plate cylinder 6 will be referred to as "Y direction", and the direction approaching or moving away from the blanket cylinder 8 will be referred to as "Z direction". I do. In addition, in the following figures, a symbol in which a cross is written in a circle is used to indicate the front and back sides of the paper.

Next, a procedure for registering (adjusting) the initial position of the plate cylinder 6 by the position adjusting device 13 will be described. When the X-direction adjustment handle 19 is rotated in the direction of the dashed arrow, the X-direction adjustment shaft 19a rotates, and the X-direction block 22 screwed thereto slides as shown by the dashed arrow. Thus, the position of the eccentric sleeve 17, that is, the plate cylinder 6, is adjusted in the X direction via the guide member 25. When the Y-direction adjustment handle 20 is rotated in the direction indicated by the solid arrow, the Y-direction adjustment shaft 20a rotates within the X-direction adjustment shaft 19a, and the Y-direction block 28 screwed thereto slides as indicated by the solid arrow. Thus, when the slide member 31 slides through the disk 30, the gear 32 and the fixed bull gear 33 rotate the slide member 31 as shown by the solid line arrow to adjust the position of the shaft 14, that is, the plate cylinder 6 in the Y direction. Is done. The pressing piece 35 of the Z-direction adjusting ring 34 is rotated in the front and back directions on the paper surface, and the eccentric sleeve 17 is
By rotating the plate cylinder 6, the plate cylinder 6 is moved in the Z direction. Therefore, after printing on the can 10 and checking the printing state of the can 10, the X-direction adjustment handle 19, the Y-direction adjustment handle 20, and the Z-direction adjustment ring 34 are aligned and operated. The plate cylinder 6 is adjusted to an appropriate position.

[0007]

However, in the above prior art, the X-direction adjustment handle 19, the Y-direction adjustment handle 20 or the Z-direction adjustment ring 34 is rotated to eliminate the displacement of the printing position with respect to the can body 10. When registering the plate cylinder 6 by moving it, there is a problem that it is difficult to adjust the X-direction adjustment handle 19, the Y-direction adjustment handle 20, and the Z-direction adjustment ring 34 to appropriate positions. For example, when the X-direction adjustment handle 19 is adjusted, the result may be directly reflected on the printing position of the can 10, but actually, the X-direction adjustment shaft 19
a, to move the eccentric sleeve 17 via the X-direction block 22 and the guide member 25,
The adjustment corresponding to the rotation amount of No. 9 cannot be performed. Therefore, in order to perform registration, it is necessary to know the amount of movement of the plate cylinder 6 corresponding to the amount of rotation of the X-direction adjustment handle 19 as a prerequisite, and there is a problem that the operation requires skill. Such operations requiring skill must be performed in the other Y and Z directions in the same manner. If the operator is not skilled, it takes a lot of work time to register and the production time is increased. There is a problem that efficiency is reduced. SUMMARY OF THE INVENTION The present invention provides a plate cylinder registration assisting device that can accurately adjust the position of a plate cylinder by assisting the registration of the plate cylinder without requiring skill.

[0008]

In order to solve the above-mentioned problems, the invention described in claim 1 is directed to a blanket (for example, blanket 7 in the embodiment) of a blanket cylinder (for example, blanket cylinder 8 in the embodiment). A registration assisting device for a plate cylinder for adjusting the initial position of a plate cylinder (for example, the plate cylinder 6 in the embodiment) to be in contact with a blanket, the shaft of the plate cylinder (for example, the shaft 14 in the embodiment). The first holding member (for example, the eccentric sleeve 1 according to the embodiment) rotatably supports at an eccentric position and is axially movable with respect to a frame (for example, the frame 15 in the embodiment).
7) and a second holding member (for example, a slide member 31 in the embodiment) that supports the shaft so that the position can be adjusted in the rotating direction, and adjusts the first holding member so as to be movable in the axial direction of the shaft. A plate cylinder axial direction adjusting mechanism, a plate cylinder plate pressure adjusting mechanism for rotating the first holding member to eccentrically rotate the shaft to adjust the plate cylinder so that it can approach and separate from the blanket cylinder, and a second holding member. A rotation adjusting mechanism for rotating the shaft to rotate the plate cylinder in the circumferential direction; and a first holding member provided with a first detection unit (for example, the guide member 25 in the embodiment). A second detection unit (for example, the disk 30 in the embodiment) is provided on the second holding member, and a position detection sensor (for example, the position detection sensor SX in the embodiment) for detecting the axial movement amount of the shaft of the first detection unit. )When, Position detecting sensor for detecting the displacement in the rotational direction of the first detecting section (e.g., the position detecting sensor SY in the embodiment) and a position sensor for detecting the displacement of the second detection section (e.g., a position detection sensor S in the embodiment
Z). With this configuration, registration by the axial adjustment mechanism of the plate cylinder can be easily performed by the position detection sensor that detects the axial movement amount of the shaft of the first detection unit, using the detection value of the position detection sensor as a guide. Can be done. Further, the registration of the distance between the plate cylinder and the blanket cylinder by the plate pressure adjusting mechanism is performed by the position detection sensor that detects the displacement of the first detection unit in the rotation direction.
The detection value of the position detection sensor can be easily obtained as a guide. In addition, the position detection sensor that detects the displacement of the second detection unit can easily register the amount of movement of the plate cylinder in the circumferential direction by the circumferential direction adjusting mechanism with reference to the detection value of the position detection sensor.

The invention described in claim 2 is characterized in that each of the detection sensors is connected to a display device (for example, the display device H in the embodiment) for displaying each detected value. With this configuration, it is possible to perform registration of the plate cylinder while watching the indicated value of the display device.

In the invention described in claim 3, the axial adjustment mechanism is connected to an axial adjustment handle (for example, the X-direction adjustment handle 19 in the embodiment), and the circumferential adjustment mechanism is connected to a circumferential adjustment handle (for example, The plate pressure adjusting mechanism is connected to a plate pressure direction adjusting ring (for example, a Z direction adjusting ring 34 in the embodiment) for rotating an eccentric sleeve as a first holding member. It is characterized by having been done. With this configuration, it is possible to register the plate cylinder simply by performing the conventional operation of operating the axial adjustment handle, the circumferential adjustment handle, and the plate pressure direction adjustment ring.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. Note that the same parts as those of the conventional configuration are denoted by the same reference numerals and described. As shown in FIG. 2, the plate cylinder (plate cylinder) 6 is detachably attached to the tip of a shaft 14 having a tapered tip, and the plate cylinder 6, that is, the shaft 14 is attached to the position adjusting device 1.
3, the position can be adjusted in the X, Y, and Z directions. A cylindrical casing 16 is supported by the frame 15. An eccentric sleeve (first holding member) 17 is supported in the casing 16 so as to be slidable and rotatable in the axial direction of the shaft 14, and the shaft 14 supports the bearing 18 in the eccentric sleeve 17. It is rotatably supported via Here, the position adjusting device 13 includes an axial adjusting mechanism, a circumferential adjusting mechanism, and a plate pressure adjusting mechanism which will be described later.

An X-direction adjustment handle (axial adjustment handle) 19 and a Y-direction adjustment handle (circumferential adjustment handle) 20 are coaxially and rotatably provided on the frame 15. The X-direction adjustment handle 19 is fixed to a pipe-shaped X-direction adjustment shaft 19a.
Is the Y-direction adjustment shaft 2 in the X-direction adjustment shaft 19a.
0a. In addition, both handles are provided with indices (not shown), and the positions can be fixed at arbitrary locations by fixing screws 21.

A thread 19b is formed at the tip of the X-direction adjusting shaft 19a. The thread 19b is screwed to the X-direction block 22. The X-direction block 22 is movably supported along a guide 23 supported by the frame 15. A bracket 24 is attached to the X-direction block 22 on the shaft 14 side.
Is formed with an engaging portion 24a. Then, an L-shaped guide member as shown in FIG.
The tip of the long piece 25a of the detection unit 25 is locked. Here, the guide member 25 is a member attached to the outer periphery of the eccentric sleeve 17 by bolts 26. The tip of the short piece 25b extends in the diameter direction of the eccentric sleeve 17, and the spring 2
7.

Therefore, as shown in FIG. 2, when the X-direction adjusting handle 19 is rotated as shown by the dashed arrow, X
The direction adjustment shaft 19a rotates, and the X-direction block 22
Slides as shown by the dashed arrow in FIG. Thus, the position of the eccentric sleeve 17, that is, the plate cylinder 6, is adjusted in the X direction via the guide member 25 which is locked to the engaging portion 24a of the bracket 24. The X-direction adjustment handle 19, X-direction adjustment shaft 19a, eccentric sleeve 17, X-direction block 22, and guide member 25 constitute an axial adjustment mechanism.

A thread 20b is formed at the tip of the Y-direction adjusting shaft 20a. The thread 20b is screwed to the Y-direction block 28. The Y-direction block 28 is movably supported along the guide 23. A bracket 29 is attached to the Y-direction block 28 on the shaft 14 side, and the bracket 29 has an engaging portion 29a. The disk (second detecting unit) 30 is locked to the engaging portion 29a.

The disk 30 is fixed to a periphery of a slide member (second holding member) 31 that is rotatably regulated by a key at the base end of the shaft 14 and is slidably supported in the axial direction. A gear 32 is attached around the slide member 31, and the gear 32 meshes with the bull gear 33. The bull gear 33 is a fixed gear, and as shown in FIG. 5, meshes with each of the gears 32 provided on the shaft 14 of each of the plate cylinders 6, at least one of which is formed as a helical tooth. Therefore, when the disk 30 moves and the slide member 31 slides, the gear 32 and the bull gear 33 mesh with each other, and the gear 32, that is, the slide member 31 rotates to rotate the shaft 14.

Therefore, when the Y-direction adjusting handle 20 is rotated as shown by a solid line arrow, the Y-direction adjusting shaft 2 is rotated.
0a rotates, and the Y-direction block 28 slides as shown by a solid arrow in FIG. As a result, the slide member 31 slides via the disk 30 locked to the engaging portion 29a of the bracket 29, and the gear 32
As a result, the slide member 31 rotates, and the position of the shaft 14, that is, the plate cylinder 6 is adjusted in the Y direction. The Y-direction adjustment handle 20, Y-direction adjustment shaft 20a, Y-direction block 28, disk 30, slide member 31, gear 32, and bull gear 33 constitute a circumferential adjustment mechanism.

In front of the eccentric sleeve 17 (left in FIG. 2)
A Z-direction adjustment ring (plate pressure direction adjustment ring) 34 for adjusting the position of the eccentric sleeve 17 so as to be freely fixed at an arbitrary position in the rotation direction is attached to the end face. As shown in FIG. 4, the Z-direction adjusting ring 34 is a ring-shaped member that rotatably supports the shaft 14 and includes a pressing piece 35. Adjustment bolt 36 supported on frame 15
By pressing the pressing piece 35 and rotating it as shown by the dashed arrow, the shaft 14,
That is, the position of the plate cylinder 6 is adjusted in the Z direction.
Here, when the eccentric sleeve 17 rotates, the short piece 25b of the guide member 25 is pressed via the spring 27 as shown in FIG. The sleeve 17 is securely fixed. Eccentric sleeve 17, Z-direction adjusting ring 3
Reference numeral 4 denotes a plate pressure adjusting mechanism.

Here, as shown in FIGS. 1 and 2, the register cylinder assisting device of the plate cylinder 6 for adjusting the initial position of the plate cylinder 6 which comes into contact with the blanket 7 of the blanket cylinder 8 with respect to the blanket 7 is used. The main part will be described. On the right side of the guide member 25 in FIG. 2, there is provided a position detection sensor SX for detecting the amount of movement of the eccentric sleeve 17 in the axial direction (dotted line arrow).
Therefore, the amount of movement of the plate cylinder 6 in the X direction can be detected by the position detection sensor SX.

On the left side of the disk 30 in FIG. 2, there is provided a position detecting sensor SY for detecting the amount of movement of the shaft 14 of the slide member 31 in the axial direction (solid line direction). Therefore, the position detection sensor SY can detect the amount of movement of the slide member 31, that is, the amount of displacement of the slide member 31, which rotates through the bull gear 33, and the shaft 14, that is, the amount of displacement of the plate cylinder 6 in the rotation direction. A position detection sensor SZ for detecting the amount of displacement of the guide member 25, that is, the eccentric sleeve 17 in the rotation direction is provided on the back side of the guide member 25 in FIG.
Therefore, the position of the shaft 14,
That is, the displacement of the distance of the plate cylinder 6 in the approaching / separating direction with respect to the blanket cylinder 8 can be detected.

As shown in FIG. 1, each position detection sensor SX,
SY and SZ are provided on the frame 15 shown in FIG.
7 attached to an arm member 38 fixed by the arm member 7. The harness 39 of each of the position detection sensors SX, SY, SZ is connected to the display device H. Display device H
Indicates the indicated value of each position detection sensor SX, SY, SZ. The arm member 38 is not shown in FIG. 2 for convenience of illustration.

Next, the operation will be described. When the X-direction adjustment handle 19 is rotated, the X-direction adjustment shaft 19a is rotated.
Rotate, and the X-direction block 22 slides as shown by the dashed arrow in FIG. This allows the bracket 24
The position of the eccentric sleeve 17, that is, the plate cylinder 6, is adjusted in the X direction via the guide member 25 which is locked to the engaging portion 24a.

At this time, the amount of movement of the plate cylinder 6 is the same as the amount of movement of the eccentric sleeve 17 which supports the plate cylinder 6 via the shaft 14. Therefore, the value measured by the position detection sensor SX and shown on the display device H is: This accurately indicates the amount of movement of the plate cylinder 6 in the X direction. Therefore, the operator only has to operate the X-direction adjustment handle 19 while checking the indicated value of the display device H without worrying about the amount of rotation of the X-direction adjustment handle 19. As a result, the operator can perform the adjustment work in the X direction without any skill.

When the Y-direction adjustment handle 20 is rotated, the Y-direction adjustment shaft 20a rotates, and the Y-direction block 28 slides as shown by the solid arrow in FIG. As a result, the slide member 31 slides via the disk 30 engaged with the engagement portion 29a of the bracket 29, the gear 32 is rotated by the bull gear 33, and the slide member 31 is rotated. 6 is rotated in the Y direction to adjust the position.

At this time, the amount of rotation of the plate cylinder 6 corresponds to the amount of rotation of the slide member 31 which rotates when the gear 32 meshes with the bull gear 33 in accordance with the amount of movement. The value measured by the detection sensor SY and shown on the display device H is exactly
In the Y direction (the amount of rotation). Therefore, the operator only needs to operate the Y-direction adjustment handle 20 while checking the indicated value of the display device H without worrying about the amount of rotation of the Y-direction adjustment handle 20. As a result, the operator can perform the adjustment work in the Y direction without any skill.

The plate cylinder 6 is moved in the Z direction by rotating the pressing piece 35 of the Z direction adjusting ring 34 in the front and back directions on the paper surface and rotating the eccentric sleeve 17 in the casing 16. Thereby, the plate pressure of the plate cylinder 6 against the blanket cylinder 8 can be properly adjusted. At this time, the amount of rotation of the eccentric sleeve 17 is
4 corresponds to a change in the distance (surface pressure) between the blanket cylinder 8 and the plate cylinder 6 caused by the eccentric movement of the plate cylinder 4, the value measured by the position detection sensor SZ and shown on the display device H is accurately calculated. In the Z direction. Therefore, the operator only has to operate the Z-direction adjustment ring 34 while checking the indicated value of the display device H without worrying about the amount of rotation of the Z-direction adjustment ring 34. As a result, the operator can perform the adjustment operation in the Z direction without any skill.

Therefore, the X-direction adjustment handle 19, the Y-direction adjustment handle 20, and the Z-direction adjustment ring 34 are operated while watching the indicated values of the display device H while sampling the printing state of the can body 10. In addition, since the registration of the plate cylinder 6 can be performed, printing can be quickly performed at an appropriate position of the can body 10 without requiring any skill in the operation. Here, since the adjustment of the plate cylinder 6 in the Z direction by the Z direction adjustment ring 34 involves the movement in the Y direction at the same time, it is desirable to perform the adjustment in the Y direction after the adjustment in the Z direction.

The present invention is not limited to the above embodiment. For example, if the amount of movement of the plate cylinder in the X, Y, and Z directions can be detected without error, the detection location is limited to the guide member 25 and the disk 30. Absent. Also, the display device H has been described by taking one plate cylinder 6 as an example,
All the sensors of each plate cylinder 6 are connected to one display device H so that each plate cylinder 6 can be switched.
Can be displayed.

[0029]

As described above, according to the first aspect of the invention, the position detecting sensor for detecting the amount of movement of the shaft of the first detecting portion in the axial direction allows the mechanism for adjusting the axial direction of the plate cylinder. Can be easily performed using the detection value of the position detection sensor as a guide. Further, the position of the plate cylinder with respect to the blanket cylinder by the plate pressure adjusting mechanism can be easily registered by using the position detection sensor for detecting the displacement of the first detection unit in the rotation direction, using the detection value of the position detection sensor as a guide. it can. In addition, the position detection sensor that detects the displacement of the second detection unit can easily register the amount of movement of the plate cylinder in the circumferential direction by the circumferential direction adjusting mechanism with reference to the detection value of the position detection sensor. Therefore, there is an effect that registration of the plate cylinder can be easily performed without requiring skill in the operation.

According to the second aspect of the present invention, since it is possible to register the plate cylinder while watching the indicated value on the display device, the operation is simplified, and accurate registration can be performed without skill. There is an effect that matching can be performed.

According to the third aspect of the present invention, it is possible to register the plate cylinder simply by performing the conventional operation of operating the axial adjustment handle, the circumferential adjustment handle, and the plate pressure direction adjustment ring. Therefore, there is an effect that the operation can be easily performed without requiring any new operation.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line AA of FIG. 3 of the embodiment of the present invention.

FIG. 3 is a side view of the embodiment of the present invention.

FIG. 4 is a cross-sectional view of the embodiment of the present invention, taken along line BB of FIG. 2;

FIG. 5 is a diagram showing an engaged state between a gear and a bull gear.

FIG. 6 is a cross-sectional view corresponding to FIG. 2 of the related art.

FIG. 7 is an overall configuration diagram of a can printing apparatus.

[Explanation of symbols]

6 Plate cylinder (plate cylinder) 7 Blanket 8 Blanket cylinder 14 Shaft 15 Frame 17 Eccentric sleeve (first holding member, axial adjustment mechanism,
Plate pressure adjusting mechanism) 19 X direction adjusting handle (axial adjusting handle, axial adjusting mechanism) 19a X direction adjusting shaft (axial adjusting mechanism) 20 Y direction adjusting handle (circumferential adjusting handle, circumferential adjusting mechanism) 20a Y Direction adjusting shaft (circumferential adjusting mechanism) 22 X-directional block (axial adjusting mechanism) 25 Guide member (first detecting unit, axial adjusting mechanism) 28 Y-directional block (circular adjusting mechanism) 30 Disk (second detecting unit) , Circumferential direction adjusting mechanism 31 slide member (second holding member, circumferential direction adjusting mechanism) 32 gear (circumferential direction adjusting mechanism) 33 bull gear (circumferential direction adjusting mechanism) 34 Z direction adjusting ring (plate pressure direction adjusting ring, plate pressure) Adjustment mechanism) SX Position detection sensor SY Position detection sensor SZ Position detection sensor H Display

Claims (3)

[Claims] A registration assisting device for a plate cylinder for adjusting an initial position of a plate cylinder which is in contact with a blanket of a blanket cylinder with respect to a blanket, wherein the frame is rotatable at a position where a shaft of the plate cylinder is eccentric and a frame. A first holding member that supports the shaft so as to be movable in the axial direction, and a second holding member that supports the shaft so that the position can be adjusted in the rotation direction thereof, and the first holding member is movable in the axial direction of the shaft. A plate cylinder axial direction adjusting mechanism for adjusting the plate cylinder, a plate cylinder plate pressure adjusting mechanism for rotating the first holding member to eccentrically rotate the shaft so as to be able to approach and separate from the blanket cylinder, and a second holding mechanism A plate cylinder circumferential direction adjusting mechanism for rotating the shaft by a member so that the plate cylinder is rotatable in a circumferential direction; a first holding member provided with a first detection section; and a second holding member provided with a second detection member. A detecting unit, and the first detecting unit A position detection sensor for detecting the amount of movement of the shaft in the axial direction, a position detection sensor for detecting a displacement of the first detection unit in a rotation direction, and a position detection sensor for detecting a displacement of the second detection unit. A registration assist device for plate cylinders characterized by the following. 2. A registration assist device for a plate cylinder according to claim 1, wherein each of said detection sensors is connected to a display device for displaying each detection value. 3. The axial direction adjusting mechanism is connected to an axial direction adjusting handle, the circumferential direction adjusting mechanism is connected to a circumferential direction adjusting handle, and the plate pressure adjusting mechanism rotates an eccentric sleeve which is the first holding member. 3. A registration assisting device for a plate cylinder according to claim 1, wherein the registration assisting device is connected to a plate pressure adjusting ring.