JPH0729410B2 - Gravure printing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a gravure printing method, and is particularly suitable for partially printing on a printing sheet wider than the width of the plate cylinder. Regarding a gravure printing method.

(Prior Art) Conventionally, as a method for performing gravure printing on a printing sheet such as a synthetic resin film, a plate cylinder is provided below the impression cylinder,
It has been common to rotate the plate cylinder to supply ink from an ink vat, scrape off excess ink with a doctor blade, and print by passing a synthetic resin film between the impression cylinder and the plate cylinder.

(Problems to be Solved by the Invention) However, in the conventional gravure printing method described above, even if excess ink is scraped off with a doctor blade, the ink rises due to centrifugal force and surface tension on both edges of the plate cylinder, and the synthetic resin Since it adheres to the surface of the film, it can be printed only on a synthetic resin film that is narrower than the plate cylinder. Therefore, even when performing narrow printing on a wide synthetic resin film, a plate cylinder having a width larger than the film width is required, which requires a large equipment cost.
Therefore, there is a problem that the printing cost is high.

(Means for Solving Problems) In the gravure printing method of the present invention, a plate knife is immersed in an ink vat, and excess ink is supplied from the ink vat onto the plate cylinder by rotation of the plate cylinder to remove excess ink from a doctor knife. It is a gravure printing method which is performed while pressing the impression cylinder through a printing sheet on the plate cylinder while scraping with a plate, in which the width dimension difference between the plate cylinder and the impression cylinder is relatively large, and both ends of the plate cylinder are The printing sheet in the vicinity of the edge is configured to be able to pass above the plate cylinder at a distance.

The distance between the printing sheet and the printing drum in the vicinity of both ends of the printing drum in the present invention cannot be unequivocally determined depending on the material of the printing sheet, but if it is too large, the printing sheet is stretched and causes wrinkles, which is small. If it is too high, the ink on the plate cylinder may adhere to the surface of the printing sheet, and it is preferable to set the interval to about 10 mm.

By the way, in order to allow the printed sheets near the both edges of the plate cylinder to pass above the plate cylinder with a space,
The feeding position of the printing sheet before and after the plate cylinder and the take-up position of the printed sheet so that the printing sheet continuously transferred on the plate cylinder passes at a predetermined interval from the horizontal tangent line of the plate cylinder. Is the simplest method, and can be set, for example, by arranging a guide roller, a guide rod, etc. at positions separated from each other in the front and rear of the plate cylinder.

Further, conventionally, the width dimension of the impression cylinder is slightly shorter than the width dimension of the plate cylinder for the reason as described above. Even if it is set to pass with a space near the edge, the rising ink may still adhere to both edges of the plate cylinder. Therefore, in the method of the present invention, the width between the plate cylinder and the impression cylinder is increased. It is necessary to make the dimensional difference relatively larger than in the past. The degree depends largely on the distance between the printing sheets near the edges of the plate cylinder, the material of the printing sheet, the amount of ink deposited, and other factors, and although it cannot be generally stated, it usually takes around 10 cm on one side. Is preferred.

(Operation) In the gravure printing method of the present invention, the width dimension difference between the plate cylinder and the impression cylinder is made relatively large, and the printing sheet near both end edges of the plate cylinder passes above the plate cylinder with a gap. Since it is obtained, the ink that rises on both edges of the plate cylinder does not adhere to the surface of the printing sheet.

(Example) Next, an example of the gravure printing method of the present invention will be described with reference to the drawings.

In the drawings, reference numeral 1 is a rotating metal plate cylinder having a diameter of 127 mm and a width of 200 mm, in which the lower end of the ink vat 2 is immersed, and a doctor knife 3 is abutted on the outer peripheral surface of the plate cylinder 1. Thus, the excess amount of ink adhering to the outer peripheral surface of the plate cylinder 1 is scraped off by the rotation of the plate cylinder 1. Above the plate cylinder 1, the feeding position of the film and the take-up position of the printed film are set in advance so that the low-density polyethylene film 5 having a thickness of 100 μ and a width of 2,000 mm is continuously transferred at intervals of 10 mm. At the time of printing, a rubber impression cylinder 4 having a diameter of 100 mm and a width of 80 mm was used, and only a part of the widthwise center of the film 5 was applied to the plate cylinder 1 at 2 kg / cm ^2.
Printing was performed by pressing with the pressure of.

Reference numeral 6 denotes an ink cover made of copper, which is softer than the surface of the plate cylinder 1, so that it may contact the plate cylinder 1 but not the film 5 in a gap between the film 5 and both edges of the plate cylinder 1. The fishing rod is attached to the holding portion of the doctor knife 3 at one end.

(Effect of the invention) The gravure printing method of the present invention involves immersing a plate cylinder in an ink vat and scraping excess ink with a doctor knife while supplying ink from the ink vat onto the plate cylinder by rotation of the plate cylinder, A gravure printing method performed while pressing an impression cylinder via a printing sheet on the plate cylinder, in which a width dimension difference between the plate cylinder and the impression cylinder is relatively large, and the plate cylinders are provided near both end edges. Since the printing sheet is configured so as to be able to pass above the plate cylinder with a gap, it is possible to perform narrow printing on a printing sheet wider than the width of the plate cylinder. The ink that has risen up does not adhere to the printing sheet, so printing can be performed inexpensively with a small printing device.

When an ink cover is provided in the gap between the film and both edges of the plate cylinder as in the embodiment, high-speed rotation of the plate cylinder causes ink droplets rising on both edges of the plate cylinder to go outward. Even if the ink is scattered, the ink does not adhere to the surface of the printing sheet, so high-speed printing can be performed.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an example of the gravure printing method of the present invention, and FIG. 2 is a longitudinal sectional view of the essential part at the center of FIG. 1 ... plate cylinder, 2 ... ink vat, 3 ... doctor knife, 4 ... impression cylinder, 5 ... printing sheet, 6 ... ink cover,

Claims (2)

[Claims] 1. A plate cylinder is dipped in an ink vat, and while the plate cylinder is rotated to supply the ink from the ink vat onto the plate cylinder, excess ink is scraped off with a doctor knife, and a printing sheet is printed on the plate cylinder. A gravure printing method performed while pressing the impression cylinder through the printing cylinder, in which the width dimension difference between the plate cylinder and the impression cylinder is relatively large, and the printing sheet near both end edges of the plate cylinder is A gravure printing method, characterized in that it can pass above with a space. 2. The gravure printing method according to claim 1, wherein an ink cover, one end of which is held by a printing device, is arranged between both end edges of the plate cylinder and the printing sheet.