JPH04327941A - Quality stabilization device of printer - Google Patents

Abstract

PURPOSE:To ensure that an optimal impression between a plate cylinder and blanket cylinder is constantly maintained in accordance with printing materials. CONSTITUTION:A physical property value of a printing material is entered into an input device 6. In addition, an information calculation processing device 7 which calculates data from the input device 6 based on each physical property value and determines an optimal impression suitable for a physical property is provided. Further, an impression adjustment device 8 which sets an interaxial distance between a place cylinder 3 and a blanket cylinder 4 automatically based on the results of calculation by the information calculation processing device 7, is installed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing press quality stabilizing device which is applied to improving and stabilizing the printing quality of an offset printing press.

0002

[Prior Art] As an example of the offset printing machine shown in Fig. 3,
The color printing unit of a newspaper offset rotary press is shown. In an offset rotary press, ink 1i and dampening water 2w necessary for forming an image on a plate (not shown) mounted on a plate cylinder 3 are supplied to an ink supply roller group 1, a dampening device, and a dampening water supply roller group 2. supplied to the plate.

The formed image is transferred to a blanket (not shown) mounted on a blanket cylinder 4 provided close to the plate, and further transferred to paper 5. The printing pressure P settings for the plate cylinder 3 and blanket cylinder 4, which determine printing quality, are determined by the operator who inspects the printed sample and determines the quality (e.g. thickening of halftone dots, adhesion of ink, etc.) Then, the distance between the axes of the plate cylinder 3 and the blanket cylinder 4 is manually set to the optimum distance using a printing pressure adjusting device (not shown).

0004

[Problems to be Solved by the Invention] The most important aspect of printing quality is the reproducibility of halftone dots forming an image, and a good M/C can be said to be a good M/C. An important point that determines the quality of halftone dot reproduction is the printing pressure P (pressing force) between the plate cylinder 3 and the blanket cylinder 4. The current printing pressure setting is manually set by the operator to the optimum printing pressure, but it cannot be the same for all materials, and the physical properties of printing materials vary depending on the manufacturer (e.g. blankets: soft,
Each time the material changes (hard, ink: soft, hard, paper: thickness, degree of unevenness of the printing surface, etc.), the operator must check the printing quality and set the optimal printing pressure. If this is not done, there will be variations in the pressing force between the plate cylinder and the blanket cylinder because they are coaxial, resulting in unstable printing quality.

FIG. 2 shows the characteristics of dot gain (the amount of thickening of halftone dots) as an example of quality evaluation items depending on the printing material manufacturers (physical property values). Due to differences in printing materials,
It is clearly seen that there is a difference in the thickness of the halftone dots. The present invention was developed in order to solve this problem, and its object is to always keep the printing pressure setting between the plate cylinder and the blanket cylinder optimal depending on the printing material.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the configuration of the present invention will be explained using FIG. 1 corresponding to an embodiment. a human-powered device 6, an information processing device 7 that processes information from the human-powered device 6 from each physical property value and determines the optimum printing pressure for the physical property;
The present invention is characterized in that it includes a printing pressure adjustment device 8 that automatically sets the center-to-axis distance between the plate cylinder 3 and the blanket cylinder 4 based on the calculation result.

[0007]

[Operation] According to the present invention, physical property values of printing materials such as blankets, ink, and paper are input to a human-powered device by the above-mentioned means, information from the human-powered device is computed by an information processing device, and the computed results are The distance between the axes between the plate cylinder and the blanket cylinder is set to the optimum value using a printing adjustment device that is automatically set.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. 1. Reference numerals 1 to 5 in the figure refer to the same parts as those of the conventional example shown in FIG. In the present invention, there is a human-powered device 6 for inputting the physical properties of the printing material, such as the softness or hardness of the blanket, the softness or hardness of the ink, the thickness of the paper, the degree of unevenness of the printed surface, etc., and the information from the human-powered device 6. An information processing device 7 calculates the optimum printing pressure for each physical property by processing each physical property value, and automatically sets the distance between the axes between the plate cylinder 3 and blanket cylinder 4 based on the calculation results of the information processing device 7. A printing pressure adjusting device 8 is provided, and each of these devices 6, 7, 8 is connected to each signal cable 9a, 9.
They are connected by b and 9c.

[0009] Thus, the information processing unit 7 processes the information on the physical property values of the printing material from the human-powered device 6 into the optimum printing conditions for each printing material. Based on this information, the printing adjustment device 8 uses a drive device (not shown) to set the distance between the axes between the plate cylinder 3 and the blanket cylinder 4 to an optimum value.

0010

Effects of the Invention As described above, according to the present invention, there is a human-powered device that inputs the physical property values of printing materials, and an information calculation that calculates the optimum printing pressure for the physical property by processing the information from the human-powered device from each physical property value. It is equipped with a processing device and a printing pressure adjustment device that automatically sets the center distance between the plate cylinder and the blanket cylinder based on the calculation results of the information processing device. This makes it possible to automatically control the optimal printing condition settings for each physical property, which has the effect of improving printing quality, consistently producing stable printed matter, and eliminating the need for the operator to set printing pressure.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

FIG. 2 is a diagram of quality variation depending on printing materials.

FIG. 3 is a schematic diagram showing a conventional example.

[Explanation of symbols]

3 Plate cylinder 4 Blanket body 6 Input device 7 Information calculation processing device 8　　　Print pressure adjustment device

Claims (1)

[Claims] Claim 1: An input device for inputting physical property values of printing materials such as blankets, ink, paper, etc., and information calculation processing that calculates information from the human-powered device from each physical property value to determine the optimum printing pressure for the physical property. 1. A quality stabilization device for a printing press, comprising: a printing pressure adjustment device that automatically sets an interaxial distance between a plate cylinder and a blanket cylinder based on the calculation results of the information processing device.