LIGHTWEIGHT ROTOGRAVURE PRINTING CYLINDER

Abstract

Rotogravure cylinders used for printing on packaging materials based on the transfer of ink onto the packaging material from the printing cylinder surface with a printing technique. The lightweight rotogravure printing cylinders developed are not heavy which prevent the factors which pose an ergonomic risk in terms of occupational health and safety and also cause an increase in logistics costs. For this purpose, the wall thickness of the steel body of the cylinder is decreased.

Claims

1. A lightweight rotogravure printing cylinder comprising: at least one body which has a hollow cylindrical form and inlets at both ends of the lateral surface of the cylindrical form that are open so as to allow access to the inner volume, and wherein at least one cover which enables to close the open inlets of the cylindrical body and to form a closed cylindrical form, at least one shaft opening that allows grasping the shaft which enables the cylindrical body to be placed on the printing machine and rotational movement to be transferred therethrough, when it is passed through the center of the cylindrical body; and at least one rib in the form of a circular plate which is spaced apart along the length of the cylindrical body extending between the covers, and enables the middle section of the cylindrical body remaining between the at least one cover to be supported from its inner surface, and has a shaft opening of a size that allows the shaft to pass through the center thereof.

2. The lightweight rotogravure printing cylinder according to claim 1, wherein the wall thickness of the steel plate material used to form the body is 3.5-7.5 mm.

3. The lightweight rotogravure printing cylinder according to claim 1, wherein the distance (L) between two consecutive ribs is in the range of minimum 1 cylinder diameter (D) and maximum 2 cylinder diameters (D).

4. The lightweight rotogravure printing cylinder according to claim 1, wherein ribs are positioned such that there will be at least 2 of them for each 1 meter of length along the length of the cylindrical body.

5. The lightweight rotogravure printing cylinder according to claim 1, wherein at least 3 ribs are positioned at equal intervals inside the cylindrical body.

6. The lightweight rotogravure printing cylinder according to claim 1, wherein the wall thickness of the rib enabling the cylindrical body to be supported from its inner surface is a maximum of 5 mm.

7. The lightweight rotogravure printing cylinder according to claim 1, wherein ribs are welded to the inner walls of the cylindrical body with a circumferential welding method (Mig-Mag method).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0015] “Lightweight Rotogravure Printing Cylinder” developed in order to fulfill the objectives of the present invention is illustrated in the accompanying figures, in which:

[0016] FIG. 1 is the exploded view of the printing cylinder of the present invention.

[0017] FIG. 2 is the view of internal structure of the printing cylinder of the present invention.

[0018] FIG. 3 is the front view and sectional view of the parts of the printing cylinder of the present invention [0019] A. is the front view of the cover piece (flange) and the illustration of A-A cross-section in this front view. [0020] B. is the front view of the rib piece and the illustration of B-B cross-section in this front view. [0021] C. is the front view of the body piece and the illustration of C-C cross-section in this front view. [0022] D. is the front view of the whole structure of the printing cylinder of the present invention and the illustration of E-E cross-section in this front view.

[0023] FIG. 4 is a graphical representation of the difference between the weight of the lightweight printing cylinder of the present invention and a standard printing cylinder having similar circumferences.

[0024] FIG. 5 is a graphical representation of the comparison of the weight changes in similar circumferences of the lightweight printing cylinder of the present invention and a standard printing cylinder.

[0025] The components shown in the figures are each given reference numbers as follows: [0026] 100. Lightweight rotogravure printing cylinder [0027] 1. Body [0028] 1.1. Inlet [0029] 2. Cover [0030] 2.1. Shaft opening [0031] 3. Rib [0032] 3.1. Shaft opening

[0033] The lightweight rotogravure printing cylinder (100) of the present invention comprises [0034] at least one body (1) which has a hollow cylindrical form and inlets (1.1) at both ends of the lateral surface of the cylindrical form that are open so as to allow access to the inner volume, [0035] at least one cover (2) which enables to close the open inlets (1.1) of the cylindrical body (1) and to form a closed cylindrical form, and has at least one shaft opening (2.1) that allows grasping the shaft, which enables the cylindrical body (1) to be placed on the printing machine and rotational movement to be transferred therethrough, when it is passed through the center of the cylindrical body (1), [0036] at least one rib (3) in the form of a circular plate which is spaced apart along the length of the cylindrical body (1) extending between the covers, and enables the middle section of the cylindrical body (1) remaining between the covers (2) to be supported from its inner surface, and has a shaft opening (3.1) of a size that allows the shaft to pass through the center thereof.

[0037] In one embodiment of the invention, the wall thickness of the steel plate material used to form the body (1) is 3.5-7.5 mm. The body (1) can be steel or its derivatives, as well as it can be composite-based materials, rigid polymer structures.

[0038] In one embodiment of the invention, the distance (L) between two consecutive ribs (3) is adjusted such that it will be in the range of minimum 1 cylinder diameter (D) and maximum 2 cylinder diameters (D):

D≤L≤2D

[0039] In one embodiment of the invention, the ribs (3) are positioned such that there will be at least 2 of them for each 1 meter of length along the length of the cylindrical body (1).

[0040] In one embodiment of the present invention, at least 3 ribs (3) are positioned at equal intervals inside the cylindrical body (1).

[0041] In one embodiment of the invention, the wall thickness of the rib (3) enabling the cylindrical body (1) to be supported from its inner surface is maximum 5 mm.

[0042] In one embodiment of the invention, the ribs (3) are welded to the inner walls of the cylindrical body (1) by circumferential welding method (Mig-Mag method). Metal Inert Gas (MIG) welding method is a metal arc welding carried out under the shielding effect of helium, argon gases and gases formed upon mixture of these gases. In this type of welding, melting occurs when the arc is formed between the workpiece and the electrode. The electrode is fed to the welding area in the form of a coil wire with controlled feeding speed. The shielding gas is blown through the torch, creating a gas layer between the molten bath and the air. There are two reasons for preferring the said welding method: It is easy to apply and advantageous in terms of cost.

[0043] The present invention relates to rotogravure cylinders used for printing on packaging materials, and it is based on the transfer of ink onto the packaging material from the printing cylinder surface with a printing technique. Thanks to the fact that the lightweight rotogravure printing cylinders (100) developed within the scope of the invention are not heavy, it is aimed to prevent the factors which pose an ergonomic risk in terms of occupational health and safety and also cause an increase in logistics costs. For this purpose, the wall thickness of the steel body (1) of the cylinder is decreased.

[0044] It is ensured that the lightweight rotogravure printing cylinders (100) of the invention, which provide a similar result in terms of printing quality, are lighter 1-75% by weight (preferably in the range of 50-60%) compared to the state of the art applications. In addition, the production of cylindrical body (1) with low wall thickness, which is carried out for the purpose of achieving light weight, enables to use less material.

[0045] Within the scope of the invention, the wall thickness of the steel plate material used to form the cylindrical body (1), the cylindrical tube-shaped structure, is selected to be 3.5-7.5 mm. This thin wall thickness provides a significant advantage compared to the current applications at the purchasing stage, as it allows the product of the present invention to be obtained by supplying the steel-containing and scrapped raw material in the closest related circumference. In the current situation, although the type of cylinder varies according to the circumference/length and technical drawing of the customer, steel pipes with an average wall thickness of 24-30 mm are used. In this context, the amount of rough cut is less and at the same time, the time of the raw material external turning process and turning cutting insert quantities are improved. In order that the lightweight rotogravure printing cylinders (100) developed within the scope of the invention can print with the same printing quality as the current cylinders with a high wall thickness, ribs (3), which are supporting parts, are placed inside the seamless tube so as to contact the inner surface of the cylindrical body (1) and are spaced apart along the length of the cylindrical body (1), thereby making the cylinders rigid. These ribs (3), which are placed or mounted therein, ensure that the lightweight rotogravure printing cylinders (100) are prevented from being deformed during their mounting to the printing machine bench by means of the shaft passed through the center of the cylindrical body (1).

[0046] Within the scope of the invention, the ribs (3), which are used to support the cylindrical form of the cylindrical body (1), are in circular form ensuring 360° contact with the inner walls of the cylindrical body (1) in the area they are placed. Therefore, possible vibrations, mechanical difficulties and surface defects that could not be eliminated in the state of the art and that may occur in production processes are avoided and it is enabled that the cylindrical body (1) is produced in a low wall thickness range. The lightweight rotogravure printing cylinders (100) of the present invention, which are produced with ribs (3), provide advantageous and faster printing with technical superiority without any problems under the working conditions they are exposed to during printing, as well as reduction in maintenance costs is achieved.