JPH029635A - Flexographic rotary press - Google Patents

Abstract

PURPOSE:To enhance printing quality and the printing durability of a printing plate by detecting the printing density and line width of a printing surface and holding the printing pressure between a plate cylinder and an impression cylinder as well as that between the plate cylinder and an anilox roller to proper values. CONSTITUTION:The aqueous ink on an anilox roller 3 is transferred to the printing plate on the adjacent plat cylinder 1 and further transferred to the printing paper 6 running between the plate cylinder 1 and an impression cylinder 2 to be printed on the printing paper 6. At this time, a printing density/line width detection apparatus 10 detects the printing density and line width of a printing surface and the obtained detection signal is sent to a printing pressure control apparatus 11 and processed to be sent to the printing pressure control motor 16a of the printing pressure control apparatus 12 to drive said motor in a forward or reverse direction. The rotation thereof is transmitted to an eccentric bearing 14 to control not only the shaft-to-shaft distance between the plate cylinder 1 and the impression cylinder 2 but also that between the plate cylinder 1 and the anilox roller 3, and the printing pressure between the plate cylinder 1 and the impression cylinder 2 as well as that between the plate cylinder 1 and the anilox roller 3 are held to proper values.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a flexographic rotary press applied to a flexographic letterpress newspaper rotary press that prints using water-based ink.

(Prior art) A conventional flexographic rotary press is explained using Fig. 3.
) is the plate cylinder, and (2) is the impression cylinder (3) adjacent to the plate cylinder (1).
is an anilox roller (4) adjacent to the plate cylinder (1);
) is the ink holder, (5) is the same ink holder (4)
2 doctor blades installed in the , (6) is the printing paper,
(7) is an ink pan disposed below the plate cylinder (1);
(8a) is the ink return pipe from the ink pan (7), (8b) is the ink return pipe from the ink holder (4), and (9) is the ink supply pipe to the ink holder (4). 1 Ink management The water-based ink pumped from the system (not shown) flows through the ink supply piping (
9) and is supplied to the ink holder (4). The same ink holder (4) has two doctor blades (5).
There is. These two doctor blades (5) are in contact with each other due to the contact pressure created by the anilox roller (3), and the water-based ink supplied from the ink supply pipe (9) to the ink holder (4) is transferred to each of the doctor blades (5). 5) Only the amount of water-based ink required for printing (the cell capacity of the anilox roller (3)) is scraped off by the anilox roller (3).
). On the other hand, the excess water-based ink scraped off by the doctor blade (5) is returned to the ink management system via the ink pan (7)-ink return pipe (8a) and is recirculated. Also, ink holder (4)
The water-based ink supplied to the anilox roller (3) is transferred to the printing plate on the adjacent plate cylinder (1), and then the printing paper (6) running between the plate cylinder (1) and the impression cylinder (2) ), and pictures and characters corresponding to the pattern on the printing plate are printed on printing paper (6).

(Problems to be Solved by the Invention) In the conventional flexo rotary press shown in FIG. and plate cylinder (1) and anilox roller (3)
) It is extremely important to set and manage the printing pressure (referred to as ani pressure) between the To set the printing pressure, press the printing pressure adjustment axis (plate cylinder (
1) Adjust the length of the printing pressure adjustment shaft (connected to the eccentric bearing that rotatably supports the printing pressure adjustment shaft) and rotate the eccentric bearing. After setting the printing pressure, adjust the printing pressure so that the printing pressure does not change. Fix the adjustment system to the frame. Kiss press is said to be the best printing pressure between the plate cylinder (1) and impression cylinder (2) for the printing plate, but in reality, the printing pressure between the first plate cylinder (1) and the anilox roller (
3) Accuracy Due to variations in the thickness accuracy of the one-plate construction, or due to heat generation in the bearings, etc. due to long-term (usually 4 to 5 hours) high-speed operation, printing pressure loss (see the arrow in Figure 5 (n)) may occur. So, the printing pressure is.

The actual printing pressure is set to a value that includes these.

The printing pressure is set to be as high as about 200 μm (see FIG. 5(II)), which is higher than the appropriate printing pressure (see FIG. 5(I)). However, when the printing paper (6) is printed with high printing pressure, the printing quality deteriorates. Furthermore, there are problems in that the stiffness of the printing plate is reduced, printing pressure is lost, and printing quality becomes unstable. Note that (1) and (II) in FIG. 4 show the relationship between the three appropriate printing pressure ranges and printing quality.

The present invention has been proposed in view of the above-mentioned problems, and its object is to provide a flexo rotary press that can improve printing quality and stiffness of printing plates.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an eccentric bearing that rotatably supports a first plate cylinder in a flexo rotary press that prints using water-based ink, and an eccentric bearing that rotatably supports the first plate cylinder. a printing pressure adjustment device having a rotational drive mechanism;

Printing density of the printing surface after the ink is transferred from the printing plate on the printing cylinder to the printing paper 1. A printing density/line width detection device detects line width, etc., and a detection signal from the printing density/line width detection device drives the printing pressure adjustment device to adjust the center distance between the plate cylinder and the impression cylinder. It is equipped with a printing pressure control device that adjusts the distance between the axes of the plate cylinder and the anilox roller.

(Function) The flexographic rotary press of the present invention is configured as described above, and supplies the water-based ink in the ink supply tank to the ink supply pump ink supply piping - ink holder - anilox roller, and also supplies the water-based ink supplied to the anilox roller. The excess water-based ink is scraped off with a doctor blade installed in the ink holder, leaving only the amount of water-based ink necessary for printing on the anilox roller, and the excess water-based ink scraped off with the doctor blade is returned to the ink pan. Printing in which water-based ink is returned to the ink supply tank via piping and recirculated, and the water-based ink supplied from the ink holder to the anilox roller is transferred to the printing plate on the plate cylinder, and then travels between the plate cylinder and the impression cylinder. When a picture or text corresponding to the pattern of the printing plate is printed on the printing paper by transferring it to the paper, the printing density/line width detection device detects the printing density, line width, etc. of the printing surface, i.e., the water-based ink. The print density of the printed surface after it has been transferred from the printing plate on the plate cylinder to the printing paper.

The detection signal obtained by the printing density/line width detection device is sent to the printing pressure control device, and the control signal obtained by processing by the printing pressure control device is sent to the printing pressure adjustment device. The printing pressure adjustment device is driven according to the printing density, line width, etc. of the printing surface, and the eccentric bearing is rotated in the forward or reverse direction to adjust the center distance between the first plate cylinder and the impression cylinder, and By adjusting the distance between the axes between the plate cylinder and the anilox roller, the printing pressure between the plate cylinder and the impression cylinder can be adjusted.
And the printing pressure between the plate cylinder and the anilox roller is maintained at an appropriate printing pressure.

(Example) Next, the flexo rotary press of the present invention will be explained using an example shown in Figs. 1 and 2. In Fig. 1, (1) is a plate cylinder, and (2) is adjacent to the plate cylinder (1). The impression cylinder (3) is the plate cylinder (1)
Anilox roller adjacent to (6) is the printing paper,
(10) is a printing density/line width detection device, and the printing density/line width detection device (10) detects the ink on the printing plate (
The printing density, line width, etc. of the printed surface after being transferred from la) to printing paper (6) are detected. Also (11
) is the printing pressure control device, (12) is the printing pressure adjustment device, (1
3a) is a signal cable connecting the printing density/line width detection device (10) and the printing pressure adjustment device (12).

(13b) is a signal cable connecting the printing pressure adjustment device (12) and the printing pressure adjustment device (12). Also, in FIG. 2 showing details of the printing pressure adjustment device (12).

(1a) is a printing plate attached to the outer peripheral surface of the plate cylinder (1).

(lb) is the plate cylinder shaft provided at both ends of the plate cylinder (1), (1
4) is an eccentric bearing, (14a) is an eccentric bearing gear provided on the outer peripheral surface of the eccentric bearing (14), and (15) is an eccentric bearing interposed between the eccentric bearing (14) and the plate cylinder shaft (lb). (16a) is the printing pressure adjustment motor, (16b) is the printing pressure adjustment gear attached to the output shaft of the printing pressure adjustment motor (16a), and the printing pressure adjustment gear (16b) is connected to the eccentric bearing gear (16a). 14a). Further, (17) is a frame that rotatably supports the eccentric bearing (I4).

Next, the operation of the flexo rotary press shown in FIG. 1.2 will be explained in detail. The water-based ink in the ink supply tank (not shown) passes through the ink supply pump (not shown) and the ink supply piping (see (9) in Fig. 3) and the ink holder (see (4) in Fig. 3). supplied to Also, the water-based ink supplied to the same ink holder is transferred to the anilox roller (3).
The excess water-based ink that exceeds the cell capacity of the anilox roller (3) is transferred to the doctor blade ((5) in Figure 3).
), leaving only the amount of water-based ink required for printing on the anilox roller (3).

On the other hand, the excess water-based ink scraped off by the doctor blade is returned to the ink supply tank via the ink pan (see (7) in Figure 3) and the ink return pipe (see (8a) in Figure 3), and is recycled again. It is circulated. Further, the water-based ink on the anilox roller (3) is transferred to the printing plate (1a) on the adjacent plate cylinder (1), and then the plate cylinder (1) and the impression cylinder (2) are transferred to the printing plate (1a) on the adjacent plate cylinder (1).
It is transferred to the printing paper (6) running between the printing plate (
Pictures and characters corresponding to the pattern 1a) are printed on the printing paper (6). At this time.

The print density/line width detection device (10) measures the print density of the print surface.

The line width ring, that is, the water-based ink is applied to the printing plate (1a) on the plate cylinder (1).
) to the printing paper (6) is detected, and the detection signal obtained by the detection device (10) is transmitted to the printing pressure via the signal cable (13a). The control signal obtained by being sent to the control device (11) and processed by the same printing pressure control device (11) is sent to the printing pressure adjustment motor (16a) of the printing pressure adjustment device (12) via the signal cable (13b). The printing pressure adjustment motor (16a) is driven in the forward or reverse direction depending on the printing density, line width, etc. of the printing surface, and its rotation is driven by the printing pressure adjustment gear (16b) and the eccentric bearing gear (14).
a) to the eccentric bearing (14), the eccentric bearing (14) rotates in the forward or reverse direction, and the distance between the axes between the first plate cylinder (1) and the impression cylinder (2), and The distance between the axes between the plate cylinder (1) and the anilox roller (3) is adjusted to reduce the printing pressure between the plate cylinder (1) and the impression cylinder (2), and the printing pressure between the plate cylinder (1) and the anilox roller. (3) The printing pressure between the two is maintained at an appropriate printing pressure.

(Effects of the Invention) As described above, the flexographic rotary press of the present invention supplies the water-based ink in the ink supply tank to the ink supply bomb ink supply piping → ink holder → anilox roller, and also supplies the water-based ink that is supplied to the anilox roller to the anilox roller. The excess water-based ink is scraped off with a doctor blade installed on the ink holder, leaving only the amount of water-based ink necessary for printing on the anilox roller, and the excess water-based ink scraped off with the doctor blade is passed through the ink pan and ink return piping. Return it to the ink supply tank.

The water-based ink that is recirculated and supplied from the ink holder to the anilox roller is transferred to the printing plate on the plate cylinder, and further transferred to the printing paper running between the plate cylinder and the impression cylinder.
When a picture or text corresponding to the pattern on the printing plate is printed on printing paper, the printing density/line width detection device detects the printing density, line width, etc. on the printing surface, in other words, when the water-based ink is It detects the print density, line width, etc. of the printed surface after it has been transferred from the plate to the printing paper, and the detection signal obtained by the printing device is sent to the printing pressure control device and processed by the same printing pressure control device. The obtained control signal is sent to the printing pressure adjustment device, and the printing pressure adjustment device is driven according to the character density of the printing surface, i width, etc., and the eccentric bearing is rotated in the forward or reverse direction to rotate the first plate cylinder. and the impression cylinder, and the axis distance between the plate cylinder and the anilox roller.
Since the printing pressure between the plate cylinder and the impression cylinder and the printing pressure between the plate cylinder and the anilox roller are maintained at appropriate printing pressures, the printing quality and the stiffness resistance of the printing plate can be improved.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of a flexo rotary press according to the present invention, FIG. 2 is a longitudinal sectional front view showing details of a printing pressure adjustment device, and FIG. 3 is a side view showing a conventional flexo rotary press. Fourth
Figures (1) and (II) are explanatory diagrams showing the relationship between the appropriate printing pressure range and printing quality, Figure 5 (1) is an explanatory diagram showing the state of appropriate printing pressure, and Figure 5 (■) is an explanatory diagram showing the relationship between the appropriate printing pressure range and printing quality. It is an explanatory view showing a state. (1)...Print cylinder, (la)...Printing plate, (2)
...Impression cylinder. (3)... Anilox roller, (6)... Printing paper, (10)... Detection device, (11) ・
...Print pressure control device, (12) ...Print pressure adjustment device, (14) ...Eccentric bearing, (16a) (1
6b) ... Rotation drive mechanism of eccentric bearing (14).

Claims (1)

[Claims] A flexo rotary press that prints using water-based ink includes a printing pressure adjustment device that has an eccentric bearing that rotatably supports a plate cylinder and a rotational drive mechanism for the eccentric bearing, and a printing pressure adjustment device that allows ink to flow from the printing plate on the plate cylinder. A printing density/line width detection device detects the printing density, line width, etc. of the printed surface after being transferred to the printing paper, and the printing pressure adjustment device is driven by the detection signal from the printing density/line width detection device. A flexographic rotary press characterized by comprising a printing pressure control device that adjusts the distance between the axes between the plate cylinder and the impression cylinder and the distance between the axes between the plate cylinder and the anilox roller.