JPS61202846A - Damping arrangement for offset press - Google Patents

Abstract

PURPOSE:To enable rotation of a ink roller to be stabilized, by a construction wherein two reciprocating rollers rotated in contact with an ink roller at a circumferential velocity equal to that of a form cylinder are provided, and an ink is supplied from one of the reciprocating rollers, while water is supplied form the other. CONSTITUTION:A reciprocating water roller 3 driven at a circumferential velocity equal to that of the form cylinder 7 is treated to be hydrophilic, and is oscillated in the axial direction. The reciprocating water roller 4 driven at a circumferential velocity equal to that of the cylinder 7 is oscillated in the axial direction. The ink roller 5 is maintained in contact with the cylinder 7 and the rollers 3, 4. The roller 5 is supplied with an appropriate uniform water film from the roller 3 after an ink is supplied from the roller 5. The thickness of the water film on the roller 3 can be controlled by regulating the nip pressures between the rollers 1, 2 and between the rollers 2, 3 and the circumferential velocities. With the roller 3 oscillated in the axial direction, uniformity of the water film in the axial direction is enhanced. The rotating velocity of the roller 5 is made to be extremely stable through contact with the rollers 3, 4 which are rotated at the same circumferential velocity as that of the form cylinder 7 and capable of being oscillated in the axial direction.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a dampening device for an offset printing press.

Conventional technology In Fig. 2, 01 is a water tray, 02 is a rubber roller, and 03 is a water tray.
is a chrome roller, 04 is an ink forming roller, 05 is an ink roller, 06 is a plate cylinder, and 07 is a blanket cylinder.

In such an apparatus, ink is supplied from an ink supply device (not shown) to an ink roller 05 via an ink mixing roller, and from the ink roller 05 via an ink forming roller 04 to a plate cylinder 06. Dampening water is drawn up from a water tray 01 by a rubber roller 02, passed through a chrome roller 03 and an ink forming roller 04, and then supplied to a plate cylinder 06. This is a so-called continuous water supply type in which the amount of water is adjusted by the nip between the chrome roller 03 and the ink inlet 204 and the difference in circumferential speed.

Problems to be Solved by the Invention The above-described system is excellent because the ink deposition roller 04 also serves as a roller, so there is less concern about ink deposition on the roller.

However, among the three nips on the ink form roller, the ink roller 051 has the same circumferential speed as the plate cylinder %, but the chrome roller 0
Since there is a difference in circumferential speed between No. 3 and No. 3, the per circumferential speed tends to become unstable, which may cause printing problems.

Means for Solving Problems In a continuous water supply type dampening device, the rotation of the ink forming roller is stabilized by driving the roller that supplies water to the ink forming roller at the same circumferential speed as the plate cylinder.

After the ink has been supplied to the inking roller by the working inking roller, the inking roller is supplied with an appropriate amount of a uniform water film by the roller of the water supply device.

Embodiment In FIG. 1, 1 is a roller that draws water from a water tray 6, 2 is a rubber roller driven by a motor together with roller 1, and a water film on rubber roller 2 is created by the difference in circumferential speed and nip pressure between rollers 1 and 2. The film thickness is adjusted.

3 is a water reciprocating roller driven at the same circumferential speed as the plate cylinder 7, which is treated to be hydrophilic and swings in the axial direction.

Reference numeral 4 denotes an ink reciprocating roller that is driven at the same circumferential speed as the plate cylinder 7 and swings in the axial direction. 5 is an ink forming roller which is in contact with the plate cylinder 7 and the roller 3.4, and 8 is a blanket cylinder. In such an apparatus, a suitably uniform water film is supplied from the roller 3 to the ink forming roller 5 in waves in which ink is supplied from the ink roller 5 . The thickness of the water film on roller 3 is that of roller 1.
, 2 and the rollers 2 and 3 and the circumferential speed ratio. By swinging the roller 3 in the axial direction, non-uniformity of the water film in the axial direction is alleviated.

By contacting the two axially swingable rollers 3 and 4 that have the same circumferential speed as the effect plate cylinder of the invention, the rotational speed of the ink inlet 25 becomes extremely stable, so printing problems are less likely to occur. At the same time, uneven conditions such as groove marks occurring in the axial direction are alleviated by the rocking.

[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. l...Water pumping roller 2...Rubber roller 3...
・Water reciprocating roller 4...Ink reciprocating roller 5...
・Ink deposition roller 7...Plate cylinder sub-agent Patent attorney
Shige Okamoto (2 people)

Claims (1)

[Claims] It is a continuous water supply type dampening device that controls the nip pressure and relative slip between the rollers to control the water film and adjust the amount of water supplied.It rotates at the same circumferential speed as the plate cylinder and contacts the ink forming roller2. A dampening device for an offset printing press, characterized in that a reciprocating book roller is provided, ink is supplied from one of the two reciprocating rollers, and water is supplied from the other.