JP2003182034A - Printing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of a non-printed part caused by the joint of a cylindrical cylinder in a printing unit and to make the tension of a web in the traveling direction uniform. <P>SOLUTION: The printing unit has a plate cylinder 12 in which both end parts 13a and 13b in the circumferential direction of a printing plate 13 are engaged with a gap 12a, and the printing plate 13 is wound on the circumferential surface and a blanket cylinder 4 fitted with a cylindrical blanket 1 in which a shaped-shaped elastic member 9 is wound/stuck on/to a cylindrical sleeve 8 and applies printing to the traveling web. In the cylindrical blanket 1, a clearance 40 extending in the axial direction is formed between both end parts in the circumferential direction of the elastic member 9, the width Wb of the clearance 40 is set to be smaller than the width Wa of the gap 12a, and the relative rotation phases of the plate cylinder 12 and the blanket cylinder 4 are set to make the clearance 40 and the gap 12a face at a nip. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing unit having a plate cylinder in which a printing plate is engaged in a gap and wound around a peripheral surface thereof, and a blanket cylinder in which a cylindrical blanket is fitted, the multicolor printing. The present invention relates to a printing unit suitable for use in a printing machine having a plurality of printing units such as a printing machine.

[0002]

2. Description of the Related Art An offset rotary press (printing machine) is provided with a plurality of printing units according to the colors to be printed. In each printing unit, the ink filled in the ink reservoir is sequentially transferred by a group of ink rollers arranged in parallel, and is appropriately kneaded in the process to form a thin ink film. Then, the formed ink film is transferred to the printing plate wound around the plate cylinder, further transferred to the outer peripheral surface of the blanket cylinder, and then printed on the traveling web by rolling contact with the blanket cylinder. ing.

By the way, since the outer peripheral surface of the blanket cylinder is made of an elastic member mainly made of rubber or the like, it is liable to be worn out or damaged and needs to be replaced. For this reason,
The outer peripheral surface of the blanket cylinder is conventionally configured to be removable. Here, FIGS. 6 to 8 are schematic views showing a typical configuration of a conventional blanket cylinder. here,
1 shows a printing unit capable of double-sided printing on a web by placing blanket cylinders on opposite sides of a sheet pass line.

FIG. 6 shows the construction of a blanket cylinder of the type in which a sheet-shaped blanket is wound around a base shaft roller. As shown in FIG. 6, the blanket cylinder 30 is provided with slit-shaped grooves 16 over the entire area of the outer peripheral surface of the base roller 24 in the axial direction, and the front and rear ends 15a and 15b of the sheet-shaped blanket 15 are provided in the grooves 16. It is configured to be inserted and gripped (fixed) via the tightening device 23.
The member indicated by reference numeral 12 in FIG. 6 is a plate cylinder, and the member indicated by reference numeral 13 is a printing plate. The plate 13 has a circumferential end 1
3a and 13b are respectively held by a gap 12a provided on the outer peripheral surface of the plate cylinder 12 and wound around the outer peripheral surface of the plate cylinder 12. The web 14 is designed to run while being sandwiched between the upper and lower blanket cylinders 30, 30.

By the way, in the sheet-like blanket 15 shown in FIG. 6, since the slit-like groove 16 is formed in the axial direction by opening on the body surface of the tightening device 23, the non-printed portion due to the slit-like groove 16 is eliminated. There is a need. By matching the rotational phase of the slit-shaped groove 16 with the rotational phase of the gap 12a of the plate cylinder 12, it is possible to suppress the generation of the non-printed portion associated with the slit-shaped groove 16.

[0006]

However, in the technique shown in FIG. 6, the circumferential width of the slit-shaped groove 16 of the sheet blanket 15 is larger than the circumferential width of the gap 12a of the plate cylinder 12. Will end up. That is, both the plate 13 and the blanket 15 are bent at both ends in the circumferential direction, and the bent ends are engaged with the gap 12a and the tightening device 23, respectively, and attached to the cylinders 12, 30. The printing plate 13 is made of a metal material (for example, aluminum material) and has a relatively small thickness (for example, 0.
3 mm), the sheet-like blanket 15 is made of an elastic member and has a thickness larger than that of the printing plate 13 (for example, 1.9 mm), so that the bending radius is larger than that of the printing plate 13.

Therefore, the circumferential width of the slit-shaped groove 16 for accommodating the bent portions of both ends of the blanket 15 is larger than the circumferential width of the gap 12a for accommodating the bent portions of both ends of the printing plate 13. It becomes. For this reason,
This technique has a problem in that it is not possible to completely prevent the generation of non-printed portions due to the slit-shaped grooves 16.

By the way, the blanket cylinder 30 of the type shown in FIG. 6 has a problem that the workability in exchanging the blanket 15 is poor and it takes a long working time. Further, a large tension is applied to the blanket 15 in the vicinity of the tightening device 23, but it is difficult to apply a tension to a portion apart from the tightening device 23. Therefore, there is also a problem that the thickness of the blanket 15 changes depending on the tension, and the initial cylinder accuracy is poor and the print quality varies.

FIGS. 7 and 8 show a blanket cylinder of a type in which a cylindrical (sleeve) blanket is fitted on a base roller. As shown in FIG. 7, the blanket cylinder 31 is provided on the outer peripheral surface of the base roller 3 to form the cylindrical blanket 1.
It is the one fitted with 0. The cylindrical blanket 10 is
It is configured by adhering a plate-shaped elastic body 17 formed of an elastic body such as rubber to the metal sleeve 8, and the cylindrical blanket 10 is formed by abutting the plate-shaped elastic body 17 at the circumferential side ends. Gap in the circumferential direction (slit groove)
There is no configuration. This prevents the occurrence of non-printed portions due to the slit-like grooves of the blanket cylinder.

As shown in FIG. 8, the cylindrical blanket 10 has a bush 7 between the frames 5a and 5b.
Bearings 6a and 6b fitted in a and 7b are rotatably supported. For this reason, when the cylindrical blanket 10 is inserted into or removed from the base shaft roller 3, one bearing 6a together with the bush 7a is once removed from the frame 5a to form a predetermined space, and the base shaft roller 3 is attached to the other bearing 6a.
It is designed to be supported in a cantilevered manner by b.

A plurality of air holes 18 are formed in the circumferential direction at the end of the outer peripheral surface of the base shaft roller 3 on which the cylindrical blanket 10 is fitted and removed. These air holes 18 are shown in FIG.
As shown in (a) and (b), it communicates with an air supply hole 19 formed inside the base roller 3, a pipe 20, a solenoid valve 21.
It is connected to the air compression source 22 via such as through, and it is possible to blow out the compressed air to the outside in the radial direction at an appropriate timing. When compressed air is fed toward the air holes 18, a compressed air layer is formed in the gap between the base shaft roller 3 and the cylindrical blanket 10. This compressed air layer enlarges the inner diameter of the cylindrical blanket 10 and facilitates fitting and removal with respect to the base shaft roller 3. The cylindrical blanket 10
Since the inner diameter of the cylinder is slightly smaller than the outer diameter of the base roller 3, the cylindrical blanket 10 is contracted by stopping the feeding of the compressed air during the operation after mounting, and It is designed to come into close contact.

Japanese Patent Laid-Open No. 2001-138477 discloses that
In such a cylindrical blanket cylinder, the plate cylinder 12 and the blanket cylinder 31 are arranged so that the gap 12a of the plate cylinder 12 and the abutting portion (seam) 17a at the circumferential end of the plate-like elastic body 17 face each other during rotation. There is disclosed a technique in which the relative rotation phase is set to prevent the occurrence of vibration due to the seam 17a.

However, since the web is supplied with ink and dampening water when sequentially passing through the printing unit, the water content gradually increases and the web easily extends along the running direction of the web. Therefore, in a rotary press that performs multicolor printing by arranging a plurality of printing units side by side, the above-mentioned amount of elongation is accumulated as it goes downstream, and the tension acting on the web (web tension) gradually increases. It tends to decrease.

In the above-described blanket cylinder 30 of the type shown in FIG. 6, even if the level of the web tension varies, the slit-like groove 16 formed on the outer peripheral surface causes the tension to escape every rotation, so that the web is loosened. Tension is easily averaged. However, in the blanket cylinder 31 as shown in FIG. 7, since there is no gap on the outer peripheral surface of the cylindrical blanket 10, it is not possible to expect the averaging of the web tension due to the tension loss unlike the blanket cylinder 30 described above.

The present invention was devised in view of such problems, and it is possible to prevent the generation of non-printed portions due to the gap of the cylindrical blanket and to make the web tension uniform in the running direction. It is an object of the present invention to provide a printing unit.

[0016]

In order to achieve the above object, in a printing unit of the present invention, both circumferential ends of a printing plate are engaged with a gap formed in the circumferential surface in the axial direction. A web cylinder having a plate cylinder wound around the peripheral surface and a blanket cylinder having a cylindrical blanket fitted by winding and pasting a plate-like elastic member around the outer peripheral surface of a cylindrical sleeve. In a printing unit for performing printing on a cylindrical blanket, a gap extending in the axial direction is formed between both ends of the plate-shaped elastic member in the cylindrical blanket in the circumferential direction, and the circumferential width of the gap is smaller than the circumferential width of the gap. Is also set smaller,
Further, the relative rotation phase of the plate cylinder and the blanket cylinder is set so that the gap and the gap face each other at the nip.

When the blanket cylinders are arranged in pairs with the web running line interposed therebetween, the gaps formed on the outer peripheral surfaces of the pair of blanket cylinders face each other on the web running line. Thus, it is preferable that the relative rotation phase of each blanket cylinder is set (claim 2).

[0018]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show a printing unit as an embodiment of the present invention.
3 is a schematic cross-sectional view of a main part of the configuration, and FIG. 2 is a diagram illustrating a relative rotation phase of the blanket cylinders arranged to face each other.
Is a schematic side view showing the configuration of the printing unit, FIG.
Is a diagram showing the configuration of the blanket cylinder, (a) is a front view of the blanket cylinder seen in the traveling direction of the web (front direction) (partially cut away), (b) is (a) )
5 is a cross-sectional view taken along line I-I of FIG.
(A)-(c) is a principal part sectional drawing by side view which shows the structure of the modification of the cylindrical blanket.

As shown in FIG. 3, the printing unit of this embodiment is configured to print on both sides of the web 14, and the plate cylinder (printing cylinder) 12 and the blanket cylinder (transfer cylinder) are arranged above and below the web 14, respectively. ) 4 is provided. In the case of a printing machine that performs multicolor printing, a plurality of such printing units are provided along the traveling path of the web 14.

As shown in FIG. 4A, the blanket cylinder 4 according to the present embodiment is composed of a base roller 3 forming an inner cylinder and a cylindrical blanket 1 forming an outer cylinder. The base roller 3 and the cylindrical blanket 1 are separate bodies, and the cylindrical blanket 1 can be attached and detached by sliding the base roller 3 in the axial direction. A flange 11 is formed at one axial end of the outer peripheral surface of the base shaft roller 3, and the flange 11 serves as a stopper to define the axial position of the cylindrical blanket 1. Although not shown, a plurality of air holes are formed in the outer peripheral surface of the base roller 3 on the side where the flange 11 is not formed as in the conventional case. When the cylindrical blanket 1 is attached or detached, compressed air is ejected from this air hole as in the conventional case, and the inner diameter of the cylindrical blanket 1 is expanded so that the cylindrical blanket 1 can be easily inserted into or removed from the base shaft roller 3.

Cylindrical blanket 1 according to this embodiment
As shown in FIGS. 4A and 4B, is composed of a metal sleeve 8 forming an inner cylinder and a plate-like elastic body 9 forming an outer peripheral surface. As in the conventional case, the metal sleeve 8 is formed so that the inner diameter is slightly smaller than the outer diameter of the base shaft roller 3, and after the fitting to the base shaft roller 3, the base shaft roller 3 is tightened from the surroundings. There is no deviation in the rotation direction and the axial direction. The plate-like elastic body 9 is a plate-like elastic member having a multi-layered structure such as a surface rubber layer, a base cloth layer, a foam layer, and the like. It is wound around the outer peripheral surface of the sleeve 8 and attached with an adhesive or the like so as to be integrated with the metal sleeve 8. Further, the outer peripheral surface of the plate-like elastic body 9 is polished so as to have a predetermined diameter after being integrated with the metal sleeve 8.

The circumferential length of the plate-like elastic body 9 is set to be slightly shorter than the circumferential length of the outer peripheral surface of the metal sleeve 8. For this reason, when it is mounted on the outer peripheral surface of the metal sleeve 8, a gap 40 is formed between both ends in the circumferential direction. With the above structure, the replacement work of the cylindrical blanket 1 with respect to the base shaft roller 3 can be performed in the blanket cylinder 4 in the same manner as in the conventional case. That is, referring to FIG. 8, first, the bush 7a fitted with the one bearing 6a that pivotally supports the base roller 3 is first removed from the frame 5a, and the cylindrical blanket 1 can be inserted and removed in the axial direction of the base roller 3 only. To form a predetermined space. Then, the old cylindrical blanket 1 is axially extracted from the base roller 3 while the base roller 3 is cantilevered by the other bearing 6b, and a new cylindrical blanket 1 is fitted on the base roller 3. Then, the removed bush 7a is fitted into the frame 5a to assemble into the original shape, whereby the replacement work is completed.

By the way, as described above, the gap 40 extending in the axial direction is formed on the outer peripheral surface of the cylindrical blanket 1. In order to prevent the gap 40 from being applied to the printing pattern surface of the printing plate, in this printing unit, as shown in FIG. 1, the width dimension Wa (in the circumferential direction) of the gap 12a formed on the outer peripheral surface of the plate cylinder 12 is For example, the width dimension Wb (for example, 1 m) in the circumferential direction of the gap 40 is larger than 1.5 mm to 3.5 mm.
m) is set small, and the gap 40 coincides with the gap 12a of the plate cylinder 12 during rotation (faces at the nip).
As described above, the relative phase between the plate cylinder 12 and the blanket cylinder 4 is adjusted.

The matching of the gap 40 with the gap 12a during rotation means that the gap 40 does not face the plate cylinder 12 through the printing plate 13 at a position (= print pattern) other than the gap 12a during rotation. And, for example, as shown in FIG. 1, the circumferential centerline C1 of the gap 40 and the gap 12a.
This can be realized by adjusting the relative rotational phases of the blanket cylinder 4 and the plate cylinder 12 so that the center line C2 in the circumferential direction of (1) coincides with the nip. Of course, if the gap 40 does not face the plate cylinder 12 at a position (= printed pattern) other than the gap 12a, the center lines C1 and C2 may not be exactly aligned in this way.

Here, as shown in FIG. 4, a marking line 41 as a mounting reference line is provided on the outer peripheral surface of the flange 11 of the base roller 3, and the cylindrical blanket is arranged so that the gap 40 matches the marking line 41. 1 is mounted so that the relative phase between the gap 40 of the cylindrical blanket 1 and the edge of the printing plate is at the correct phase position.

Further, as shown in FIG. 2, in the blanket cylinders 4 and 4 arranged in pairs with the running line of the web 14 sandwiched therebetween, a gap 40 formed on the outer peripheral surface of each blanket cylinder 4 and 4. , 40 face each other on the running line of the web 14, and the rotational phases of the blanket cylinders 4, 4 are set respectively. Since the printing unit as one embodiment of the present invention is configured as described above, the following actions and effects can be obtained.

That is, the gap 40 of the cylindrical blanket 1
There is an advantage that it is possible to prevent the printing pattern surface of the printing plate 12 from being affected, and to prevent a non-printing portion due to the gap 40 from being generated. Further, as described above, when performing multicolor printing, dampening water is supplied to the web 14 together with the ink each time printing is performed through a plurality of printing units, so that the physical properties of the web 14 change gradually. It becomes easier to grow.
The blanket cylinder 4 of the present embodiment has a gap 40 formed in the circumferential surface thereof and extending in the axial direction. Since the gap 40 is recessed inward from the other outer peripheral surface of the blanket cylinder 4, the blanket cylinder 4 rotates and the gap 40 causes the web 14 to move.
When hit, the engagement between the blanket cylinder 4 and the web 14 weakens for a moment. Therefore, when there is a difference in the tension of the web 14 between the upstream side and the downstream side of the blanket cylinder 4, the tension loss occurs in the gap 40, and the tension acting on the web 14 is made uniform between the upstream side and the downstream side. There are advantages.

Particularly, since the gaps 40, 40 formed on the outer peripheral surfaces of the blanket cylinders 4, 4 arranged so as to sandwich the web 14 come to face each other on the running line of the web 14, the above tension loss is eliminated. It can be more effective. Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the gap 40 of the cylindrical blanket 1, the ink and the cleaning liquid enter between the layers forming the plate-shaped elastic body 9 from both circumferential ends of the plate-shaped elastic body 9.
In order to prevent the plate-like elastic body 9 from peeling off from the metal sleeve 8 and the layers from peeling from each other, the both circumferential ends are not exposed to ink or a cleaning liquid for cleaning the ink. It may be configured to be transparent.

As a concrete method, as shown in FIG. 5A, a seal member impermeable to ink or a cleaning liquid for cleaning the ink is provided at both circumferential ends of the plate-like elastic body 9. 2 may be attached, or a coating agent impermeable to the ink and the cleaning liquid may be applied in a range indicated by a thick line in FIGS. 5B and 5C. Further, in the above-described embodiment, the relative rotation phase of each blanket cylinder 4, 4 is such that the gaps 40, 40 formed on the outer peripheral surfaces of each blanket cylinder 4, 4 face each other on the traveling line of the web 14. Although set, even if the gaps 40, 40 do not face each other on the running line of the web 14, the gap 40 is not covered by the blanket cylinder 4
Since it is recessed more inward than the other outer peripheral surface, tension loss occurs in the gap 40, and the tension acting on the web 14 can be made uniform on the upstream side and the downstream side.

[0030]

As described in detail above, according to the printing unit (Claim 1) of the present invention, a gap extending in the axial direction is formed between the circumferential ends of the plate-like elastic member in the cylindrical blanket. At the same time, the circumferential width of the gap is set smaller than the circumferential width of the gap of the plate cylinder, and the relative rotation phase of the plate cylinder and the blanket cylinder is set so that these gaps and the gap face each other at the nip. Since it is set, it is possible to prevent the gap of the cylindrical blanket from contacting the printing pattern surface of the printing plate, prevent the occurrence of non-printed parts due to this gap, and the web tension is released from the gap. When installed in a color printing machine, there is an advantage that the tension of the web in the running direction can be made uniform.

In the case where the blanket cylinders are arranged in pairs across the web running line, the above-mentioned gap formed on the outer peripheral surface of each pair of blanket cylinders is on the running line of the web. By setting the relative rotation phase of each blanket cylinder so as to face each other at 1, there is an advantage that the tension of the web can be made more effective (claim 2).

[Brief description of drawings]

FIG. 1 is a diagram illustrating a configuration of a printing unit according to an embodiment of the present invention with a base roller omitted, and is a schematic cross-sectional view of a main part in a side view.

FIG. 2 is a diagram showing a relative rotation phase of the blanket cylinders arranged to face each other according to the embodiment of the present invention, and a schematic cross-sectional view of a main part in a side view.

FIG. 3 is a schematic side view showing a configuration of a printing unit as an embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a blanket cylinder according to an embodiment of the present invention, in which (a) is a front view of the blanket cylinder seen in the traveling direction (front direction) of the web (partially broken and shown. (A) and (b) are views showing a cross section taken along the line I-I of (a) with the base shaft roller omitted.

5 (a) to 5 (c) are cross-sectional views of a main part in a side view showing a configuration of a modified example of the cylindrical blanket according to the embodiment of the present invention.

6A and 6B are schematic diagrams showing a typical configuration of a conventional blanket cylinder, in which FIG. 6A is an axial sectional view, and FIG. 6B is an external view seen from the front direction (part of which is a sectional view).

FIG. 7 is a schematic view showing a typical configuration of a conventional blanket cylinder, (a) is an axial sectional view and (b) is a front sectional view.

8 is an explanatory diagram for explaining a method of replacing a cylindrical blanket in the blanket cylinder shown in FIG.

[Explanation of symbols]

1 Cylindrical blanket 2 Seal member 3 spindle rollers 4 blanket body 5a, 5b frame 6a, 6b bearing 7a, 7b bush 8 metal sleeve 9 Plate-shaped elastic body (plate-shaped elastic member) 11 flange 12 plate cylinder 12a gap 13 printing plates 14 Web 40 Gap between elastic sheets 41 scribe line

Claims (2)

[Claims] 1. A plate cylinder in which both circumferential end portions of a printing plate are engaged with a gap formed in the circumferential surface in the axial direction, and the printing plate is wound around the circumferential surface, and an outer peripheral surface of a cylindrical sleeve. A blanket cylinder in which a cylindrical blanket formed by winding and adhering a plate-like elastic member on the blanket cylinder is fitted, and a printing unit for printing on a running web is provided. A gap extending in the axial direction is formed between both ends in the circumferential direction, the circumferential width of the gap is set to be smaller than the circumferential width of the gap, and the gap and the gap face each other at the nip. A printing unit, wherein a relative rotation phase of the plate cylinder and the blanket cylinder is set. 2. The blanket cylinders are arranged in pairs with the web running line interposed therebetween, and the gaps formed on the outer peripheral surfaces of the pair of blanket cylinders face each other on the web running line. The printing unit according to claim 1, wherein the relative rotation phase of each blanket cylinder is set as described above.