JPH01141743A - Detection of appropriate amount of wafer in offset press - Google Patents

Abstract

PURPOSE:To adjust an appropriate amount of wafer early in start of printing and to enable variation of the amount of feed water to be controlled in operation, by establishing at least one piece of a water amount detection roller for detection of an amount of water going up to an ink roller group in the ink roller group. CONSTITUTION:When the amount of feed water to a plate surface of a plate cylinder PS increases and an amount of water going up to ink rollers A, B,... following that, ink stripping to water amount detection rollers a-c occurs, and ink becomes not to get on the water amount detection rollers a-c. Therefore, by comparing with a thickness of an ink film, the ink thin film on the water amount detection rollers a-c becomes thin, and the texture of the water amount detection rollers a-c comes to be finally exposed. By observing this variation, an water amount regulating scale of a water original roller is adjusted, and the amount of water going up to the ink rollers A, B,... and in its turn, the amount of feed water to the plate surface can be finely controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting an appropriate amount of water in an offset printing press.

[Conventional technology] Offset stamp! In the i1 machine, when the amount of water supplied to the printing plate is large, the amount of water flowing up to the ink roller also increases, causing floating stains, thickening halftone dots, and decreasing gradation reproducibility. A phenomenon occurs where the quality becomes unstable or the print quality deteriorates.

As a way to deal with this kind of deterioration in print quality,
The methods listed below are used.

(1) Observe the land stains and floating stains on the printed matter and adjust the water scale.

(2) Visually observe the printing plate and control the level by checking the lighting conditions on the printing plate.

(3) Half a glass of water! The thickness is measured using an optical device, and the amount of water is controlled so that the thickness of the water belly remains constant.

[Problems to be Solved by the Invention] However, the conventional method (1) of observing stains on printed matter has the problem that the response is slow, making it complicated to control the amount of water and resulting in a large amount of wasted paper. . Furthermore, the conventional method (2) requires skill and is subject to individual differences, so there is a problem of reliability. Furthermore, in method (3), the method of measuring the water film on the printing plate using a measuring device has a problem in that the measuring device is an isi.

The present invention has been made in view of the above points, and an object thereof is to provide a method for detecting an appropriate amount of water in an offset stamping machine that is inexpensive, simple, and has excellent responsiveness.

Means and operation for solving problem E] In an offset printing press, at least one water amount detection roller for detecting water blistering on the column to the ink roller group is installed in the ink roller group, thereby reducing the cost. This is a method for detecting an appropriate amount of water in an offset printing machine, which is simple and has excellent responsiveness.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the main parts of an offset printing press. In the figure, PS is the plate cylinder, P, Q, R.

S, U, T are dampening rollers, A, B, C, D, E.

G, H, L, M, N, W, X, Y, and Z are ink rollers. In an embodiment of the present invention, the water amount detection rollers are arranged at positions a, b, and C. First, in the first embodiment, the water amount detection roller is placed at position a, the material of the roller surface is Or plating, and the second
In the embodiment, the water amount detection roller is placed at position B, and the material of the roller surface is anodized to 2. In the third example, the water amount detection roller is placed at position C, and the material of the roller surface is Cr. '203 thermal spray material, in the fourth embodiment, the water amount detection roller is placed at the C position, and the roller surface material is Or plating, and in the fifth example, the water bladder detection roller is placed at the a position, and the The material of the roller surface is anodized Al.

In either embodiment, as the amount of water supplied to the plate surface of the plate cylinder PS increases, the ink rollers A, 8.・・・
・When the measured water ■ increases, the water amount detection rollers a-C
Ink stripping occurs, and ink no longer gets on the water amount detection rollers a-C. Therefore, the thin ink film on the water amount detection rollers a to C° becomes thinner than when the amount of water is at a proper level, and the background of the water detection roller is finally exposed.

This change can be used to control the water amount adjustment scale of the water base roller. Since this change is caused by a slight change, it is possible to perform minute I control of the amount of water flowing upward to the ink roller and, ultimately, the amount of water supplied to the printing plate.

By using the above-mentioned materials as the materials for the water amount detection rollers a-C, the hydrophilicity of the water amount detection controller is strengthened, so that it is easy to combine with dampening water, and the ink and dampening water on the water amount detection rollers are made to be strong. This makes it easier to replace the ink with water, and the water amount detection roller makes it easier to strip the ink.

By the way, if the water amount detection roller is set at the a position, it is in a position where it is easy for the operator of the printing press to take care of the water amount, so it is suitable for observing changes in the water amount detection roller. Further, if the water amount detection roller is set at position b, the film thickness is the same as that of the water film surface of the printing plate, so changes corresponding to changes in the water film of the printing plate can be observed.

Furthermore, if the water amount detection roller is set at the C position, changes in water temperature can be detected most sensitively.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to quickly adjust the appropriate amount of water at the beginning of printing, and to detect the appropriate amount of water in an offset printing machine that can detect changes in the amount of water supplied during operation. method can be provided.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an offset printing machine according to an embodiment of the present invention. PS... plate cylinder, P, Q, R, S, T... dampening 0-ra, a-C... water amount detection roller. Applicant's agent Patent attorney Takehiko Suzue

Claims (3)

[Claims] (1) A method for detecting an appropriate amount of water in an offset printing press, comprising installing at least one water amount detection roller in an ink roller group to detect the amount of water flowing upward to the ink roller group. (2) The surface material of the water amount detection roller is Cr plating, anodized Al, Cr_2O_3, Al_2O_3
2. A method for detecting an appropriate amount of water in an offset printing press according to claim 1, characterized in that an oxide ceramic such as ZrO_2 is used. (3) In the offset printing machine according to claim 1, wherein the lightening of the ink due to the decrease in ink transfer on the water amount detection roller is detected and the water amount adjustment memory of the water base roller is controlled. Appropriate water amount detection method.