JPS61202847A - Damping arrangement for offset press - Google Patents

Abstract

PURPOSE:To enable stable high-quality printing without using any high- concentration alcohol, by a construction wherein a damping roller group provided with a transfer roller between it and a form damping roller is combined with an in roller group, in a brush-type water supply device having the function of regulating water quantity in the longitudinal direction of rollers by a shutter. CONSTITUTION:A water feed roller 3 is rotated in synchronism with the form cylinder 7, and is oscillated in the axial direction. The transfer roller 5 is rotated by mechanical drive or drag, and is fixed or oscillated in the axial direction. Since an ink built up on the ink roller 6 has a flowing property similar to that of an ink in the ink roller system and an ink built up on a form damping roller 4 is replaced by a fresh ink supplied from the transfer roller 5, emulsification of the ink by water reaches an equilibrium condition at a fixed level, thereby stopping the progress of the build-up, the fact having been actually provided with a continuous water supply type damping arrangement using alcohol. When the water supply device is replaced by a brush roller type one, damping water not containing any alcohol can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an offset printing press with a plan roller dampening device.

Conventional technology The main methods of supplying dampening water to offset printing machines are: fist type, splash type using a brush roller, continuous water supply type using a roller nip, and Φ spray type. In addition, the place where water is supplied can be divided into those that are supplied to the φ plate surface and those that are supplied to the ink roller row.

Among these methods, the method of supplying water to the printing plate using a plan roller (see FIG. 2) is one of the methods currently in common use.

In FIG. 2, 01 is a copper plating roller, 02 is an ink forming roller, 03 is a water forming roller, 04 is a chrome plating roller, 05 is a shutter, and 06 is a brush type water supply device.

In such an apparatus, ink is supplied from an inking roller (not shown) to a copper plating roller 01, and from an inking roller 02 to a plate cylinder 07.

Dampening water is supplied from a brush roller dampening device 06 to a chrome plating roller 04, and from a dampening roller 03 to a plate cylinder M.

Problems to be Solved by the Invention In the brush roller type dampening device, ink tends to accumulate on the dampening roller through the plate surface (lack of quality stability).

In addition, to reduce this effect, the surface of the water-forming roller is wrapped with a highly water-retentive material such as Molton or Sleeve (this is common practice, but this hinders the improvement of printing quality and increases the effort required for maintenance). is inviting.

It has been confirmed in the case of a continuous water supply type dampening device that the accumulation of ink on the dampening roller can be improved by passing the roller between the dampening roller and the ink roller group. A drawback of the method of metering water in the nip between the rollers is that it is impossible to finely adjust the amount of water supplied in the axial direction of the plate cylinder in accordance with the pattern on the plate. In addition, highly concentrated aqueous alcohol solutions are generally required for operation of this type of equipment.

Means for solving the problem By combining a brush type water supply device with a shutter-based water flow adjustment function in the longitudinal direction of the rollers with a dampening roller group having a passing roller between the inking roller group and the dampening roller. Stable, high-quality printing is possible without using high-concentration alcohol.

The ink deposited on the active applicator roller is replaced by fresh ink supplied from the transfer roller, and the emulsification of the ink with water is brought into equilibrium.

Embodiment In FIG. 1, 1 is a brush roller dampening device that uses a brush 7 to scatter water droplets, 2 is a split shutter device for adjusting the amount of water supplied in the longitudinal direction of the roller, and 3 is a dampening device for receiving water droplets. Water reciprocating roller, 4 is the water that passes between roller 3 and the plate cylinder! l roller, 5 is the water forming roller 4, and the ink layer is the roller 6.
A passing roller 7'' is provided between the two, 7 is a plate cylinder, and 8 is a blanket cylinder.

In such a device, the water reciprocating roller 3 rotates in synchronization with the plate cylinder 7 and swings in the axial direction.

The transfer roller 5 rotates by mechanical drive or co-rotation, and is fixed or swingable in the axial direction.

In the ink layer, the ink deposited on the roller 6 flows like the ink in the ink roller system by providing the transfer roller 5, and the ink deposited on the water forming roller 4 flows on the transfer roller 5. At a certain level, the emulsification of ink with water reaches an equilibrium state, and no further deposition occurs.
Proven in continuous water dampening equipment that uses alcohol.

Here, if the water supply device is replaced with a brush roller type as in the present invention, dampening water that does not contain alcohol can be used.

Effects of the invention (1) Since there is no need for a moult or sleeve on the surface of the water-forming roller, the printing quality is improved compared to the conventional brush roller method, and maintenance is easier.

Since the balance between ink and water is stable, there is no need to readjust Z even after long hours of operation.

C. You can use dampening water that does not contain alcohol.

Second, by using a shutter, it is possible to adjust the amount of water supplied depending on the pattern on the plate.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of a dampening device for an offset printing press according to the present invention, and FIG. 2 is a schematic diagram of a conventional device. 1... Brush roller dampening device 1. 4...Water Make roller, Death...Transfer roller, 6.
...The ink layer is on the roller, and 7...the plate cylinder. Sub-agent: Patent attorney: Shige Okamoto, 2 other people

Claims (1)

[Claims] A dampening device for an offset printing press, characterized in that a transfer roller is provided between a dampening roller and an ink forming roller of a brush roller type dampening device.