JPH0156672B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sheet-fed offset printing machine that overprints the same image multiple times on the same substrate, and provides a sheet-fed offset printing machine that can obtain high-density printed images and high-accuracy resolution. The purpose is to

The known methods of overprinting the same image on the same printed matter are by repeatedly using a well-known single-color press, or by attaching plates of the same image to a multi-color printing press and performing overprinting. However, the printing machines used in these methods originally had a mechanism for printing in multiple colors using plates for each color created by color separation. The cylinder and printing cylinder are independent for each printing unit, and the printing material is transferred between each unit using a delivery cylinder or the like. For this reason, it is extremely difficult to maintain and adjust the diameter, accuracy, printing conditions, transfer and delivery accuracy, etc. of the plate cylinder, blanket cylinder, and printing cylinder in perfect condition, and it is extremely difficult to maintain and adjust the diameter, accuracy, printing conditions, transfer and delivery accuracy, etc. of the plate cylinder, blanket cylinder, and printing cylinder in perfect condition. Although this was sufficient, it was not suitable for overprinting using the same plate.

Conventionally, other known overprinting methods used a flatbed type proofing machine, but the printing speed was extremely slow and it was only applicable to limited applications.

The sheet-fed offset printing machine according to the present invention was developed in view of the above points, and is capable of high-speed and highly accurate overprinting. The sheet-fed offset printing machine of the present invention can perform overprinting on paper, film, various flexible sheets, etc., and the case of paper will be described below.

The sheet-fed offset printing press of the present invention has a printing unit equipped with one cylinder, a plurality of blanket cylinders provided around the cylinder, and an inking device corresponding to the number of blanket cylinders, or an inking device and a dampening water supply device. In a sheet-fed offset printing machine having one or more cylinders, the diameter of the cylinder is an integer multiple of the blanket cylinder, and the surface of the cylinder is provided with a printing unit having a plate mounting part and a gripper that grips the substrate, and the cylinder It is characterized in that images of the same plate can be overprinted multiple times on the same substrate during one rotation without causing any misalignment.

Furthermore, by appropriately connecting printing units having the above-mentioned characteristics, it is possible to overprint the same image on the front and bottom surfaces of the substrate, that is, both sides, or to overprint one color or multiple colors using multiple plates on one or both sides. do. When printing on both sides, it is common to use plates with different images for the front and back sides, but it is also possible to use plates with the same image.

The printing press according to the present invention is extremely suitable for printing circuits, nameplate printing, etc.

FIG. 1 shows a basic type of printing press according to the present invention,
It is capable of overprinting the same image twice with one plate, and includes a cylinder having a paper feeding device, a delivery cylinder, a plate mounting section, and a printing section, and two sets of dampening water supply devices and inking devices. It consists of a paper discharge device including two blanket cylinders and a paper discharge cylinder, an ink drying device, etc.

The cylinder S has two blanket bodies B ₁ and B ₂
The plate 2 is attached to the plate mounting portion 1 of the cylinder S by a plate fixing member 3 provided in the undercut portion. Adjacent to the plate mounting section 1, a printing section 4 is provided at the circumferential pitch of the blanket cylinders _B1 and _B2 . A plate mounting member 3 is attached to the front edge of the printing section 4.
A gripper 5 for gripping the printing paper is provided in the undercut portion shared with the gripper 5. Note that the blanket cylinders B ₁ and B ₂ are determined by the maximum dimension of the plate 2. Once the maximum size of the plate to be used has been determined and the blanket cylinders B ₁ and B ₂ have been determined, the cylinders should be designed taking into account the installation conditions of the dampening water supply device, inking device, space for plate cleaning work, ink drying device, etc. The diameter of S is determined. However, the cylinder diameter must be an integral multiple of the diameters of the blanket cylinders B ₁ and B ₂ . The reason why it must be an integer multiple is that, as is easily understood, the relative positions between the plate and the blanket cylinder, and between the printing section and the blanket cylinder must always be constant. The possible value of this integer multiple is twice or more, but realistically it is three times or more. but,
If a dry offset method without a dampening water supply device is used, it is possible to double the amount. If the printing size is further increased to 4 or 5 times, additional blanket cylinders and inking devices are added, making it possible to perform three or four overprints.

Overprinting by the printing machine shown in FIG. 1 is performed according to the following flow. The printing paper P sequentially fed from the paper feeder F is registered at the tip of the feeder board 16, and then transferred to the swing gripper 1.
Gripper 19 of transfer drum 18 by 7
and then to the gripper 5 of the printing section 4 of the cylinder S, which rotates at the same circumferential speed. Prior to this, the plate 2 is fixed to the plate attachment part 1 of the cylinder S by plate attachment members 3, 3.
After receiving water supply from the first dampening water supply device 7, ink is transferred to the printing area by the first inking device 8, and then the ink in the printing area is transferred to the first blanket cylinder _B1 . Ru. Due to the rotation of the cylinder, the gripping side of the plate 2 is transferred to the next second dampening water supply device 1.
0 and the second inking device 11 area.

On the other hand, the printing paper P in the printing section 4 is supplied to the dampening water supply device 7.
and inking device 8, contact with these devices must be broken. As a means for this purpose, dampening water supply device and ink supply device release cams 6 are provided at both ends of the printing section of the cylinder S, and the cams are pressed into contact with cam followers provided on the device side (not shown). , whereby the device is retracted outwardly from contact with the printing paper. When the printing section 4 comes to the first blanket cylinder _B1 position, the blanket cylinder rolls into contact with the printing paper P, and the first blanket cylinder
The ink forming the image on _B1 is transferred to the image on plate 2.

Next, as the cylinder S rotates, the plate 2 to which ink has been resupplied by the second inking device 11 comes into contact with the second blanket cylinder _B2 , and the ink on the plate is transferred to the second blanket cylinder _B2. Ru. Then, the ink from the second blanket cylinder B2 is transferred so as to be correctly superimposed on the image already printed for the first time by the first blanket cylinder _B1 on the subsequently arriving printing paper P of the printing section ₄ . The images of the same plate 2 are printed on the printing paper P in a superimposed manner. Note that the relative position between the plate 2 and the printing paper P is fixed, and the rotation of the blanket cylinder is driven by gears from the cylinder drive system, so once adjusted to ensure accurate overprinting, the There is no need for misaligned printing to occur. In addition, the first
The positions of the blanket cylinder _B1 and the second blanket cylinder _B2 are independent of the exact overprinting conditions, and can be placed at any position within a design-permissible range.

The ink drying devices 9 and 13 using infrared rays or ultraviolet rays act only to dry the ink on the printing paper P, and do not act when the plate 2 passes.

The printed paper P, which has been printed for the second time by the second blanket cylinder _B2 , is passed to the paper discharge cylinder 14 of the paper discharge device and is discharged and stacked.

Furthermore, an undercut portion 12 is formed in the portion other than the plate mounting portion 1 and the printing portion 4 to prevent dampening water and ink from adhering.

Furthermore, although the embodiment shown in FIG. 1 is equipped with a dampening water supply device, the dampening water supply device can be omitted if dry offset ink and a waterless plate are used. . Of course, even if the printing press is equipped with a dampening water supply device, dry offset printing can be performed if the device is always set in an inactive position.

FIG. 2 shows another embodiment, which is of a type that allows overprinting on the front and back sides of the printing paper P, respectively. Note that the dampening water supply device, inking device, ink drying device, etc. are omitted in the figure. These devices are provided according to the embodiment shown in FIG.

In this type of printing press, a well-known reversal transfer method is used, and the printed paper P overprinted by the first printing unit U ₁ centered on the cylinder S ₁ is transferred to the gripper on the first transfer cylinder 20. 2
1 and then taken over by the reversing cylinder gripper 31 of the reversing cylinder 30 located adjacent to the first transfer cylinder. The back end of the printing paper P delivered to the reversing cylinder 30 is attracted by the vacuum head 32. Next, the gripper 41 of the second transfer cylinder 40 grips the printing paper at its end, follows a path as shown by the dotted line, and delivers it to the gripper 50 of the cylinder _{S 2} of the second printing unit U 2 . Note that the gripper 41 of the second transfer cylinder 40 is adapted to rotate in a direction opposite to the rotational direction of the transfer cylinder while revolving with the rotation of the transfer cylinder 40 from the illustrated state.

FIG. 3 shows yet another embodiment, in which different images are printed on the front side of the printing paper, and each image has two
This shows a type that can be overprinted several times.
In the figure, a dampening water supply device, an inking device, etc. are omitted. In this model, the first printing unit U ₁
1 to pass from the printing unit U2 to the second printing unit _U2 .
Two delivery cylinders 20 are provided so that overprinting can be performed twice on the same side, and overprinting of two colors is possible.

FIG. 4 shows still another embodiment, in which two sets of single-sided, two-color overprinting type printing machines shown in FIG. This is a printing machine that uses two plates for the front and back sides, and overprints each plate twice.

FIG. 5 shows another example for overprinting on the front and back sides of the printing paper, similar to the embodiment shown in FIG. 2, in which a first printing unit U ₁ and a second printing unit U ₂ are used.
This is a type of printing machine that has two transfer cylinders between them, and in this case the paper ejecting device is higher than in other examples.

[Brief explanation of drawings]

Figure 1 shows the mechanism of a printing press that overprints on one side, Figure 2 shows the mechanism of a printer that overprints on both sides, and Figure 3 shows the mechanism of a printing press that overprints two colors on one side. Fig. 4 is a mechanical diagram of a printing press that performs two-color overprinting on both sides, and Fig. 5 is a mechanical diagram of a double-sided overprinting printing machine that has another reversal transfer mechanism.
B ₁ , B ₂ ...B ₈ is the blanket cylinder, F is the paper feeder,
P is printing paper, S ₁ , S ₂ , S ₃ , S ₄ are cylinders, U ₁ ,
U ₂ , U ₃ , U ₄ are printing units, 1 is a plate mounting part,
2 is a plate, 4 is a printing unit, 5 is a gripper, 6 is a cam, 7, 10 is a dampening water supply device, 8, 11 is an inking device, 9, 13 is an ink drying device, 20,
40 represents a transfer cylinder, and 30 represents a reversal cylinder.

Claims (1)

[Claims] 1. A printing unit comprising one cylinder, a plurality of blanket cylinders provided around the cylinder, and an inking device/or an inking device and a dampening water supply device corresponding to the number of blanket cylinders. 1
In a sheet-fed offset printing machine having one or more cylinders, the diameter of the cylinder is an integral multiple of the diameter of the blanket cylinder, and the surface of the cylinder is provided with a printing unit having a plate mounting part and a gripper that grips the substrate, and the cylinder 1. A sheet-fed offset printing machine that is capable of overprinting images of the same plate multiple times on the same printing material without causing any deviation during one rotation of the press. 2. When there are two printing units, the printed material that has finished overprinting the same image on the front side in the first printing unit is transferred to the second printing unit via a transfer cylinder/or a transfer cylinder and a reversing cylinder, or without them. 2. A sheet-fed offset printing machine according to claim 1, wherein the second printing unit overprints the same image on the back side using another plate. 3. At least two or more identical image overprinting printing units are connected to each other so that multiple images of one color or multiple colors are overprinted on the front side/or the front side and the back side of the substrate using multiple plates. A sheet-fed offset printing machine according to claim 1.