JP2808025B2 - Rubber roll for gravure printing - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impression cylinder rubber roll for electrostatic deposition gravure printing.

[Prior Art] In gravure printing, a printing paper is pressed by an impression cylinder roll and pressed against a plate surface of a plate cylinder. The plate surface is composed of extremely fine ink cells in each part of the image, and the depth of each ink cell has a depth difference corresponding to the density of the image. When the printing pressure is applied, the ink in the ink cells on the plate is transferred to the paper and printing is performed. At this time, electrostatic gravure printing has been developed as a technique for promoting the transfer of the ink to the paper surface. In electrostatic gravure printing, the surface of the impression cylinder is made of conductive rubber, and when a voltage is applied across the printing paper between the impression cylinder and the plate cylinder, the ink in the cells has an induced charge, The electric field and the resulting electric charge on the printing paper surface transfer to the printing paper.

2. Description of the Related Art Conventionally, an impression cylinder rubber roll used in electrostatic gravure printing has an ebonite layer functioning as an insulating material formed on the surface of an iron core, and a conductive rubber layer formed thereon. In some cases, ceramic is used instead of ebonite.

[Problems to be Solved by the Invention] However, in such a conventional impression cylinder rubber roll, the adhesive force between the insulating material and the conductive rubber material is insufficient, and peeling may occur due to strong pressure during printing. . In particular, when ebonite is used as the insulating material, the insulating property may be insufficient.

For this reason, development of a rubber roll for gravure printing having a large adhesive force between the insulating material and the conductive rubber material and having sufficient insulating properties is desired.

The present invention has been made in view of the above circumstances, the adhesive force between the insulating material and the conductive rubber material is large,
Further, it is an object of the present invention to provide a rubber roll for gravure printing having a sufficient insulating property.

[Means for Solving the Problems] In response to this object, a rubber roll for gravure printing of the present invention is provided with an insulating layer made of sprayed ceramic, a sprayed iron layer, and a conductive rubber layer sequentially laminated on the surface of an iron core. It is characterized by:

[Operation] Good insulation from the iron core is obtained by the sprayed ceramic layer formed on the surface of the iron core.

Further, since the rubber has good adhesiveness to the sprayed iron layer formed on the surface of the ceramic layer, the conductive rubber can be satisfactorily attached.

As a result, the transfer of the ink from the cells on the plate surface to the printing paper is favorably performed, and the durability of the conductive rubber roll is improved.

[Embodiment] Hereinafter, details of the present invention will be described with reference to the drawings showing one embodiment.

In FIG. 1, reference numeral 1 denotes an impression cylinder rubber roll. The impression cylinder rubber roll 1 has an iron core 2. The iron core 2 is made of steel. An insulating layer 3 is formed on the surface of the iron core 2. The insulating layer 3 is formed of a ceramic base material by thermal spraying, for example, plasma spraying. The thickness of the insulating layer 3 is selected to have an insulating property with respect to an applied voltage (for example, -20 KV) described later. The thickness of the insulating layer 3 varies depending on the composition of the ceramic and the applied voltage, but is usually preferably 3 mm to 10 mm. As the composition of the ceramic, for example, alumina, titania, and white alumina can be used.

A sprayed iron layer 4 is formed to cover the surface of the insulating layer 3. The sprayed iron layer 4 is formed by spraying iron on the insulating layer 3. All of the sprayed layers are made up of flat small metal particles. Therefore, fine irregularities are present on the surface of the sprayed iron layer 4. The thickness of the sprayed iron layer 4 is 0.1mm-1mm
It is.

A conductive rubber layer 5 is formed covering the surface of the sprayed iron layer 4. The conductive rubber layer 5 has a surface resistance of 0.5 to 5 MΩ and a thickness of 10 mm to 50 mm. As such a conductive rubber, for example, carbon-filled NBR can be used.

The conductive rubber layer 5 is formed by applying a conductive rubber on the sprayed iron layer 3 and then volatilizing and removing the solvent.

The impression cylinder rubber roll 1 configured as described above is used as follows.

As shown in FIG. 2, the impression cylinder rubber roll 1 is disposed to face the plate cylinder 11, and the printing paper 12 passes between the impression cylinder rubber roll 1 and the plate cylinder 11, and is pressed by the impression cylinder rubber roll 1. To press against the plate cylinder 11.

DC 20 between the impression rubber roll 1 and the conductive rubber layer 5
The conductive rubber layer 5 is charged by applying a potential difference of KV.
The ink 15 in the cells 14 of the plate surface 13 of the plate cylinder 11 is supplied to the printing paper 12 by the printing pressure provided by the impression cylinder rubber roll 1.
At this time, the ink 15 in the ink cell 14 has an induced charge, and is transferred to the printing paper 12 surface by the electric field of the impression rubber roll and the resulting electric charge on the printing paper 12 surface.
Thereby, the transfer of the ink is performed favorably.

[Effect of the Invention] In the present invention, since the ceramic sprayed layer is used as the insulating layer in the impression cylinder rubber roll, the insulating property is extremely good.

Further, the conductive rubber is not formed directly on the insulating layer, but a sprayed iron layer is formed on the insulating layer, and a conductive rubber layer is further formed thereon. Rubber has excellent conformability to iron, and the surface of the sprayed iron layer has minute irregularities, so that the adhesion of the rubber to the sprayed iron layer is extremely good. Also, there is no occurrence of peeling even under high pressure during printing.

From this, in the present invention, it is possible to obtain a rubber roll for gravure printing having a large adhesive force between the insulating material and the conductive rubber material, high durability, and sufficient insulating properties.

[Brief description of the drawings]

FIG. 1 is an explanatory view in vertical section of an impression cylinder rubber roll according to an embodiment of the present invention, and FIG. 2 is an explanatory view showing a use state of the impression cylinder rubber roll. DESCRIPTION OF SYMBOLS 1 ... Rubber roll of impression cylinder, 2 ... Iron core, 3 ... Insulation layer, 4 ... Sprayed iron layer, 5 ... Conductive rubber layer, 11 ... Plate cylinder cylinder, 12 ... Printing paper, 13 ... Plate surface , 14 …… cell, 15 …… ink

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41F 9/00 B41N 10/00-10/04

Claims (1)

(57) [Claims] 1. A rubber roll for gravure printing, comprising an insulating layer made of sprayed ceramic, a sprayed iron layer and a conductive rubber layer sequentially laminated on the surface of an iron core.