JPS58124652A - Offset rotary press - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a rotary offset printing press having at least two printing mechanisms, each of which has one plate cylinder, one blanket cylinder, one inking mechanism and one dampening mechanism. These printing mechanisms are associated with at least one impression cylinder.

Offset rotary printing presses can produce high quality printing in almost all types of printing. However, this does not apply to printing using metal powder inks. That is, in this case, it is impossible to prevent the dampening liquid from entering the inking mechanism, and the duration of action of the dampening liquid on the metal powder ink becomes longer, so that the metal powder ink becomes unclear after printing. From the viewpoint of printing as clearly as possible with this metal powder ink, it is advantageous to print this metal powder ink by letterpress printing.

The object of the invention is to improve a rotary offset printing press of the type mentioned at the beginning so that one printing mechanism can be converted to letterpress printing without changing the path of the substrate and at a low cost. Our objective is to provide a rotary offset printing press that can.

According to the present invention, this problem has been solved by the structure described in claim 1.

By using the configuration of the present invention, it is not only possible to print metal powder ink in a printing mechanism that prints without using dampening liquid, but also the rubber cylinder of the downstream offset printing mechanism can be used during operation. This is avoided when using a pre-installed printing mechanism that performs letterpress printing by removing this letterpress ink and then transferring the letterpress ink to the printing substrate again in the correct register to even out the ink unevenness of the letterpress ink. It is also possible to avoid ink unevenness on the printing surface, which is impossible to prevent.

BACKGROUND OF THE INVENTION Web-fed rotary printing presses which can be operated selectively by offset printing or letterpress printing are well known (see German Patent Application No. 1,611,239, in particular FIG. 2). However, according to this type, if five printing cylinders are used, printing can only be done by either letterpress printing or offset printing. Moreover, this type has the disadvantage that the printing cylinder must be covered with either a letterpress printing plate or an offset printing plate, so that the path of the substrate must be varied depending on the respective printing type.

Two embodiments of the invention will now be described in detail with reference to the drawings.

In the embodiment shown in FIG. 1, there are two forme cylinders 1.2, associated inking units 3 and dampening units 5,
6 are provided one each. The plate cylinder 1 is constructed in such a way that it can optionally be covered with an offset printing plate or a rubber blanket.

Each form cylinder 1.2 cooperates with one blanket cylinder 7,8. The blanket cylinder 7 is constructed so that it can be covered with not only a rubber blanket but also a letterpress printing plate selectively. The plate cylinder 1, the inking mechanism 3, the dampening mechanism 5, the blanket cylinder 7 and the plate cylinder 2, the inking mechanism 4, the dampening mechanism 6, the blanket cylinder 8 together with a common impression cylinder 9 each form one printing mechanism 11. 12.

The impression cylinder 9 whose surface is made of metal is provided with a member for applying a rubber blanket.

During operation, sheets of printing material 13 are fed one after another to both printing mechanisms 11, 12 in the direction of arrow a. These sheets are then gripped by the glyph grooves of the impression cylinder 9 and guided from this dazzle until they are transferred to the glyph A of the conveyor chain 10. Conveyance chain device 1
0 is guided by a chain gear provided on the shaft of the blanket cylinder 8. This transport chain 10 transports the sheets to a downstream printing mechanism or to a sheet delivery device.

If both plate cylinders 1, 2 are covered with offset printing plates and both blanket cylinders 7.8 are covered with a rubber blanket, one side of the guided sheet is covered with the rubber blanket that is covered with both blanket cylinders. The blanket prints two different colors sequentially. In this case both inking mechanisms 3.4 and both dampening mechanisms 5, 6 are functional.

If letterpress printing is to be carried out in the first printing mechanism, the dampening mechanism 5 is brought into an inactive position, the plate cylinder 1 is covered with a rubber blanket, and the blanket cylinder 7 is covered with a letterpress printing plate. . Similarly, the impression cylinder 9 is also covered with a rubber blanket.

During operation, the ink supplied by the inking mechanism 3 is uniformly applied to a rubber blanket stretched over the plate cylinder 1 and transferred from this rubber blanket to the letterpress printing plate stretched over the blanket cylinder 7. Letterpress printing is carried out between the blanket cylinder 7 and the impression cylinder 9 using ink of the first color accordingly. Especially when printing thin sheets of paper, the metal surface of the impression cylinder 9 and the blanket cylinder 7
It is advantageous if the impression cylinder 9 is covered with a rubber plunger in order to avoid mutual damage to the relief printing plate covered with it.

Then, in the second printing mechanism 12, the plate cylinder 2
and blanket cylinder 8, offset printing is carried out on the sheets using ink of a second color. The ink printed on the sheet by the letterpress printing plate on the blanket cylinder 7 is brought into contact with the blanket cylinder 8 immediately after printing, so that the sheet has a small amount of the ink printed by the letterpress printing method on the blanket cylinder 8. Hand over to the surface. However, during operation of the printing press, the sheets pick up this ink from blanket cylinder 8 again. Therefore, the rubber cylinder 8 and the impression cylinder 9
Along the printing line, there is not only offset printing using ink supplied through the inking mechanism, but also dubbing printing using ink supplied through the letterpress printing plate. is also carried out.

By this means, the image printed with the ink supplied by the inking mechanism 3 can have the sharpness of offset printing even if it is printed by letterpress printing.

Therefore, this arrangement is applicable not only to printing with metallic powder ink, but also when printing is to be carried out without any color variations. Such color variations cannot always be completely avoided in the offset printing method due to the strong action of dampening water.

The embodiment shown in FIG. 2 is provided with two printing mechanisms 21, 22 which are separated from each other.

These printing mechanisms 21, 22 each have one impression cylinder 23 or 24, one blanket cylinder 25 or 26, one plate cylinder 27 or 28, one inking mechanism 29 or 30, and one dampening mechanism 31 or 32. The strip-shaped printing material 33 is guided in the direction of arrow a between the blanket cylinder 25 and the impression cylinder 23 and between the blanket cylinder 26 and the impression cylinder 24, and is passed through the printing mechanisms 21 and 22. Of course, if it is desired to print using three or more colors of ink with this printing machine, more printing mechanisms can be provided.

When performing two-color offset printing, the plate cylinder 27.2
8 is covered with an offset printing plate, and blanket cylinders 25 and 26 are covered with a rubber blanket. In this case both inking mechanisms 29.30 and both dampening mechanisms 31.32 function.

On the other hand, if printing is to be performed using the letterpress printing method in the printing mechanism 21, the dampening mechanism 31 is brought to the inactive position, and the rubber blanket is placed on the plate cylinder 27.
A letterpress printing plate is pasted on 5. The impression cylinder 23 is also covered with a rubber blanket.

Also in the arrangement of this embodiment, the ink printed by the printing mechanism 21 is transferred to the printing mechanism 22 by the strip-shaped printing material 33.
is brought to the rubber cylinder 26. Therefore, along the printing line between the impression cylinder 24 and the blanket cylinder 26, not only pure offset printing with ink supplied by the inking mechanism 30 takes place, as in the embodiment of FIG. Since dubbing printing is also performed using ink supplied via the letterpress printing plate stretched on the blanket cylinder 25, the sharpness of offset printing can be obtained with respect to both the ink printed by the offset printing method and the letterpress printing method. I can do it.

[Brief explanation of drawings]

FIG. 1 shows a sheet-fed printing press according to the invention, and FIG. 2 shows a web printing press. 1... Plate cylinder, 2... Plate cylinder, 3... Ink mechanism, Cow... Ink mechanism, 5... Dampening mechanism, 6... Dampening mechanism, 7... Rubber cylinder , 8...Rubber cylinder, 9...Impression cylinder,
10... Conveyance chain device, 11... Printing mechanism, 1
2... Printing mechanism, 13... Printing material, 21... Printing mechanism, 22... Printing mechanism, 23... Impression cylinder, 24
...Impression cylinder, 25...Rubber cylinder, 26...Rubber cylinder, 2
7... Plate cylinder, 28... Plate cylinder, 29... Ink mechanism, 30... Ink mechanism, 31... Dampening mechanism, 32...
...Moistening mechanism, 33...Band-shaped printing material.

Claims (1)

[Claims] 1. An offset rotary printing press having at least two printing mechanisms, each of which has one plate cylinder, one blanket cylinder, one inking mechanism, and one dampening mechanism,
In those types in which at least one impression cylinder is assigned to these printing mechanisms, the printing mechanism (11, 21) located upstream in the direction of passage of the printing material (13, 33) is used for letterpress printing. A plate cylinder (1, 27) configured to be able to be covered with a rubber blanket, a blanket cylinder (7, 25) configured to be able to be covered with a letterpress printing plate and brought into an inactive position during the printing operation. An offset rotary printing press, characterized in that it is equipped with a dampening mechanism (5, 31) configured to allow. 2. The pressure of the printing mechanism is configured so that a letterpress printing plate can be stretched on the rubber cylinder (7, 25), and the cylinder (9, 23) is provided with a member for stretching a rubber blanket, a patent. An offset rotary printing press according to claim 1.