JPH11227151A - Flexographic printing machine - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To realize flexographic printing with excellent appearance over a large area. A plate (5) for transferring ink to a printing substrate (6) is provided with a plate (2).
The plate cylinders 1A and 1B are held in a belt-like manner and rotated. As a result, the separation angle 7 between the plate 5 and the printing material 6 can be kept large, and the time from when the ink is transferred from the anilox roll 3 to when the printing is performed can be shortened, and high quality printing can be performed. Becomes

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexographic printing machine capable of printing a large area.

[0002]

2. Description of the Related Art As shown in FIG. 2, a conventional flexographic printing press mainly comprises three rolls: a doctor roll 2, an anilox roll 3, and a plate cylinder 1. First, ink is supplied from the upper part of the doctor roll 2 to form an ink reservoir 4 with the anilox roll 3, and the ink is uniformly and thinly spread on the anilox roll 3. Next, the ink on the anilox roll 3 is transferred to the plate 5 on the surface of the plate cylinder 1, and the plate cylinder 1 is rotated on the printing material 6, whereby the plate 5 is rotated.
Is transferred.

[0003]

When printing on a large area with such a flexographic printing press, the diameter of the doctor roll 2 and the anilox roll 3 can be reduced without any problem.
The plate cylinder 1 necessarily has a large diameter in order to secure a circumference corresponding to a large-area printing portion. However, as the diameter of the plate cylinder 1 increases, the separation angle 7 between the printing material 6 and the plate 5 decreases, and depending on the viscosity and printing speed of the ink, a trailing unevenness (referred to as une. .1 to 1.0
mm, a peak-to-valley difference of about 50 to 500 °) became noticeable, which was a problem in appearance.

Further, the center position of the anilox roll 3 and the doctor roll 2 for supplying ink to the plate 5 must be set at the same or higher position as the center of the plate cylinder 5 in order to prevent ink dripping. When the diameter of the plate cylinder 1 is increased, it takes a long time until the ink transferred from the anilox roll 3 to the plate 5 is transferred to the printing material 6, and the surface of the ink on the plate is dried. It was also a factor.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a plate for transferring ink to a print substrate is held on a plurality of rolls in a belt shape and rotated. Accordingly, a flexographic printing press capable of large-area printing is provided.

[0006]

FIG. 1 is a sectional view of an example of a flexographic printing press according to the present invention. Instead of the conventional large-diameter plate cylinder 1,
By providing the plate cylinders 1A and 1B having small diameters, holding the plate 5 over these rolls in a belt shape, and rotating the plate 5, printing on a large area was enabled. Further, it is preferable that the plate 5 is prevented from sagging by the tension roll 8.

[0007] By providing a plurality of small-diameter plate cylinders in this manner, the separation angle 7 between the printing material 6 and the plate 5 can be increased, and the drip after printing is prevented. When one conventional large-diameter plate cylinder is used, the diameter of the plate cylinder is 500 m.
m is the limit, but as in the present invention, by providing a plurality of small-diameter plate cylinders, a large area can be easily obtained by increasing the distance between the plate cylinders while maintaining a large separation angle from the printing material. Printing (for example, about several meters in the printing direction) becomes possible.

When one conventional large-diameter plate cylinder 1 is used, it takes a lot of time for the ink transferred from the anilox roll 3 to the plate 5 to be transferred to the printing material 6, and a large amount of time is required on the plate. However, as in the present invention, by providing a plurality of small-diameter plate cylinders, the ink transferred from the anilox roll 3 to the plate
The time required for the transfer to the toner is reduced, and the drip after printing is prevented.

[0009]

EXAMPLE Printing was performed by a flexographic printing machine as shown in FIG. As the plate 5, a PET film serving as a base having a thickness of 0.5 mm, a circumference of 3 m, and a convex portion (printed portion) having a length of 2 m was used. The joint of version 5 is
The base PET film was thermocompression bonded.

[0010] The two plate cylinders 1A having a diameter of 200 mm
And 1B, the ink was supplied via an anilox roll 3 having a diameter of 100 mm and a doctor roll 2 having a diameter of 50 mm, and printing was performed on a glass plate as a printing material 6. The printing width was 50 cm. The plate 5 was tensioned by a tension roll 8 using an air cylinder to prevent slack. The appearance after printing was extremely excellent, equivalent to printing using a single plate cylinder having a diameter of 200 mm in the related art.

[0011]

According to the present invention, it is possible to maintain a large separation angle between the plate and the printing material and to shorten the time from when the ink is transferred from the anilox roll to when the printing is performed. It is possible to perform high-quality printing over a large area equivalent to using one small-diameter plate cylinder.

[Brief description of the drawings]

FIG. 1 is a sectional view of an example of a flexographic printing press according to the present invention.

FIG. 2 is a cross-sectional view of an example of a conventional flexographic printing press.

[Explanation of symbols]

 1, 1A, 1B: Plate cylinder 2: Doctor roll 3: Anilox roll 4: Ink pool 5: Plate 6: Printed material 7: Separation angle 8: Tension roll

Claims (1)

[Claims] 1. A flexographic printing machine capable of printing a large area by holding and rotating a plate for transferring ink onto a printing material in a belt shape over a plurality of rolls.